MST-Plant and Microbial Sciences

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Abundance and Conservation Status of Prunus Africana in Western Mau Forest, Kenya
(Kenyatta University, 2020-03) Chebet, Gladys
Prunus africana (Hook. f) Kalkman, 1965 (formerly Pygeum africanum Hook.f) is a geographically widespread tree restricted to highland forest of main land Africa and outlying islands. The species is commercially important for its bark, which is used in the treatment of prostate gland disorders. It also produces high quality timber used locally for building poles and furniture as well as fuel wood. The high demand for the bark has led to notable destruction of the species in natural forests, leading to concerns on the long term sustainability of harvesting and the conservation of the species. Despite the fact that Mau forest is a protected area, the region experiences illegal exploitation with P. africana being one of the main targets. The tree is of great demand for its strong timber and highly medicinal bark making its population to be under threat. As a result P. africana is listed as vulnerable species under Appendix II of CITES. In this study, information on P. africana was obtained mainly from literature survey while population data was obtained by sampling methods. The study was conducted in Western Mau forest (longitude E35027.05’ to E35039.42’ and latitude 0010’46’’S to 0017’42’’S) which is found in the South Rift region, Kericho county. Transects were laid across four blocks in Western Mau forest and diameter at breast height (dbh) and height of mature trees measured. The level and causes of disturbances were collected using questionaires and through observation and recorded for each of the plots. Saplings were counted and recorded in subplots and seedlings counted in micro plots. Densities of seedlings, saplings and mature P. africana trees were examined across the Western blocks of Mau forest. A socio-economic survey was further conducted to determine community perceptions on the status of the tree under study. The data generated were analyzed using both descriptive and inferential statistics. Data on height and dbh were summarized as mean ± SE and variations tested using one way ANOVA. Socio-economic data were mainly analyzed in form of proportions and variations between sites tested using chi-square statisctics.Data was presented in histograms, tables and graphs. Inferential statistics revealed significant variation in the density of saplings (p<0.05). Majority of the mature trees were of height between 20m and 40m though this height varied significantly between the blocks. As concerns dbh, most of the trees ranged between 40cm and 50cm with a signigficant variation between the blocks. The seedling numbers exceeded saplings and trees, suggesting potential for regeneration and population increase even though the population is not increasing. Observations showed that human activities, herbivory and diseases pose serious threats to P. africana tree. The local community was of the opinion that the main anthropogenic activities affecting the tree are unsustainable de-barking, logging, and animal grazing. It was recommended that awareness creation be organized regularly for all stakeholders on sustainable de-barking and logging be greatly regulated to save this tree of great value to mankind. The local community and more so those who rely on the tree for herbal medicine should be encouraged to grow the tree in their homestead gardens to reduce the pressure on wild trees thereby enhancing its conservation.
Agronomic evaluation and molecular genotyping of selected soybean (glycine max (l) merril) varieties grown in different environmental regions of East Africa
(2013-09-06) Okwany, Zedekiah W. Agina
Soybean (Glycine max. (L)Merril) is one of the most popular pulses in the world. It has been known to man for a long time since its first record goes as far as 2500 BC in China and Manchuria. Glycine max belongs to the subgenus soja, which also contains G. soja and G. gracilis. Soybean is grown primarily for the production of seed, has a multitude of uses in the food and industrial sectors, and represents one of the major sources of edible vegetable oil and of proteins for livestock feed use. Genes greatly determine morphological characteristics of living organisms. Environmental conditions may also determine these characteristics, some of which are important in agronomy. This study aimed at investigating the relationship that exists between agronomic and molecular characteristics of selected soybean cultivars grown in different regions of East Africa. The results will be used to advice both the farmers and researchers on the cultivar they cultivate/study and their relationship to agronomic value respectively. This information will also be used in breeding programmes. In this research, different soybean cultivars from different regions of East Africa (Kenya, Uganda and Tanzania) were grown in different blocks within one region (Mbita point in Kenya). Agronomic characteristics were observed and recorded from germination to post harvest time. For molecular analysis, genomic DNA was extracted according to Phenol Chloroform method. This was followed with PCR process using custom ordered pair of primers that corresponded to the flanking ends of the targeted gene fragment (5S ribosomal genes). Restriction Fragment Length Polymorphism (RFLP) was then performed on the isolated PCR fragments by digesting DNA using various restriction enzymes determined by computer based simulation of already sequenced genes of known Glycine species. Gene clean was performed on PCR materials. The elute was confirmed on agarose gel then sent for automated sequencing ABI prism (AppliedBiosystems) at (ILRI). The resulting gene sequences were compared with gene sequences of known Glycine species using various enzymes in computer based simulations. This enabled get a marker (Sac II) for the 5S ribosomal genes in Glycine max. The gene sequences were then subjected to gene blast using MEGA 4 and resulted with a phylogenetic tree for the East African soybean. The studied cultivars were found to be closely related to Glycine max. RFLP results were compared with agronomic performance. There was significant difference in plant height (F= 106.131, df = 12, p<0.05); number of branches (F=25.227, df =12, p<0.05); weight of the whole plant (F = 6.634, df = 12, p<0.05); total number of seeds per plant from the various cultivars (F = 13.330, df = 12, p<0.05); weights of total seeds per plant from various cultivars (F = 5.124, df =12, p<0.05). Significance differences observed in various parameters analysed in this study were not reflected in the cultivars’ genetic characteristics. The marker (sac II) identified in this research will be useful in further research in soybeans. The best performing cultivars (TGX-1876-2E, Namsoy 4M, Nam II and Nyala) will also be recommended for soybean farmers around Lake Victoria region. These results will also assist plant breeders to produce hybrids from the best performing cultivars.
Analyses of microbial hazards of lake Victorial Nile Perch (lates niloticus) processing at industrial level in Kenya
(2012-04-05) Mungai, Daniel N.; Mwatha, W. E.; Okemo, P. O.
The quality of processed seafood produced for international market should conform to international standards. Over the last few decades, major seafood importing countries have introduced hygiene regulations and legislation, including definitive standards for fishery products. In 1991, European Union (EU), which is the largest single market for Kenya's Nile perch products established regulations laying down health conditions for production and the placing on the market of fishery products. The kenyan Nile perch industry has been caught unaware and is not geared to meet such requirements. This led to a subsantial rejection of consignments and subsequent economic losses. Decomposition and the presence of pathogenic organisms have been indicated as the main reasons for most of these rejections. To meet the EU requirements, Nile perch processing establishments have to implement a quality control system based on the principles of Hazard Analysis Critical Control point (HACCP). Implementation of such a system requires an assessment of microbial hazards likely to occur during the processing of processing of Nile perch. To address this requirement, analyses of microbial hazards during the processing of Nile perch were conducted in two establishments over a period of eight months. The analyses consisted of observating all operations of fish processing, measuring temperature of fish throughout the processing line and collecting samples and testing them for common fish-borne pathogens and indicator microorganisms. Among the procedures followed for microviological examination of samples are those recommended by the International Commission on Microbiological Specifications for Foods (ICMSF). Results showed that the fish received at the processing establishments had aerobic mesophilic colony count (AMCC) of less than 10(6) CFU/g with hydrogen sulphide (H2S) producing bacteria accounting for less than 3 percent of AMCC. Enterobacteriaceae, coliforms, faecal coliforms and Sataphylococcus aureus counts of raw fish were within the limits recommended by ICMSF. vibrio cholerae and Clostridium perfringens were isolated only from the incoming whole fish and their incidences in both establishments were 1.4 percent and 0.5 percent respectively. Salmonella was present in 5 percent of incoming whole fish and in 16.7 percent fo fish samples collected after the fish was filleted in one establishment. Shigella spp. was not recovered from any fish sample. The processing operations in both establishments resulted in significant reduction of all the microbial parameters tested. However, it was observed that certain microbial hazards existed during the fish processing operations in both establishments, particularly under circumstances of poor handling of fish. Whole fish washing, filleting, beheading and gutting, fillet skinning, control of fish temperature and sanitation and establishment hygiene were identified as Critical Control Points (CCPs) at or by which the identified microbial hazards could be controlled. The study recommended that Nile perch processing establishments should put in place control measures aimed at eliminating, preventing or minimising the microbial hazards.
Analysis of biological science course in diploma colleges: a case study of Kenya Science Teachers Colelge
(2012-05-17) Ngano, Electina Nafula
This research was carried out to find out the suitability of the biological science course offered in Diploma Colleges to the teaching of the 8.4.4. biological science syllabus of secondary school education. The survey was a case study of Kenya Science Teachers College. The sample was drawn from second year biological science students, the tutors of biological science at K.S.T.C and biological science graduate teachers of K.S.T.C from some few schools in Bungoma, Tranzoia and Kakamega districts. The instrument of the research was the questionnaire designed to find out, the course schedule as well as the opinions of the subjects on the course. The 8.4.4. being a new educational programme, its eventual success depends very much on the teachers who are to teach at all levels of learning. This research was therefore very timely, and the purpose of the research was to find out if there are any inadequacies in the training programme of biological science teachers at K.S.T.C make recommendations for possible improvement. The ideal of a suitable teacher-training programme were elicited in the review of the literature related to this study. This also more clearly exposed the objectives of this research. The results of this study are limited to Kenya Science Teachers College situation. However the recommendations would apply to other similar institutions.
Anti-mycobacterial efficacy of selected medicinal plants used by herbal practitioners in Kisii to treat tuberculosis.
(2014-05-05) Amboga, Enock Bichang'a; Okemo, P. O.; Mbugua, P. K.
Tuberculosis (TB) is a global problem of staggering proportions. It is known to be a poverty related disease affecting millions of people in the world's poorest countries. Tuberculosis is difficult and expensive to control. Due to emerging resistance or the bacterium to available drugs, there is need 10r renewed strategies 011 treatment and prevention, hence development of new antimicrobials. The search for effective drugs lor Mycobacterium is paramount. Mycobacterium infections especially those caused by Mycobacterium fortuitum, M. avium complex, M. clielonae and M. tuberculosis have increased in patients with Acquired Immunodeficiency Syndrome (AIDS). Infections caused by these bacteria, especially Mycobacterium avium complex are difficult to treat because the bacteria are resistant to multiple drugs. It is however, noted that a large proportion of the Kenyan population is using herbal medicine to combat several ailments including tuberculosis. Unfortunately scientific data to support the efficacy of herbal preparations is insufficient. This study surveyed plants used by Abagusii traditional medical Pl\~ctitioners to treat TB. Six plants from the survey reputed tobe WidelY.used in the treatm nt of TB were selected, botanically identi fied as Spermacoce princeae, Warburgia gandensis, Solanum aculeastrum, Carissa edulis, Synadenium glaucescens and Toddalia asiatica and were tested for anti-mycobacterial activities. The various plant parts (roots, stems, leaves and flowers) were dried in the shade and ground to powder, which was stored in sterilized sample bottles. Extraction in Erlen Meyer flasks was done using cold water, hexane, chloroform and methanol. The extracts were tested against Mycobacterium tuberculosis strain provided by the Nairobi Hospital, known to be resistant 10 rifampicin, streptomycin and isoniazid. The plants found to have active antimycobactrial agents, were assayed further for identification of compounds to be used in treatment of tuberculosis. The Growth Index (G.!) of Mycobacterium tuberculosis ill the various extracts were determined and used as a measure or efficacy. The plants with active antimycobacterial extracts were screened for phytochemical compounds with medicinal values used for treatment of TB. Extracts of Synadeuium glaucesccus, Warburgia ugandensis, Carissa edulis and Toddalia asiatica registered activity at 2 mg/ml. Methanolic extracts had a p value of 0.048 hence more effective in extracting the antimycobacterial compounds from plant materials. Toddalia asiatica methanolic crude extract was the most active extract against Mycobacterium tuberculosis. Since Toddalia asiatica registered impressive activity further research on cytotoxicity and in vivo activity should be carried out. It is also important to formulate capsules of tablets from the extracts. This type of identification of secondary metabolites produced by plants with antimycobacterial activities will enhance the search Ior efficacious anti – tuberculosis agents.
Antibiogram, Metal Tolerance and Plasmid Profiles of Pathogens Isolated from Wastewaters and Sludge of Abattoirs in Nairobi, Kenya
(2014-02-24) Nyamboya, Rosemary Atieno; Okemo, P. O.; Ombori, O.
Because of the prevalence of antibiotic resistant pathogenic bacteria, infectious diseases are becoming more difficult and expensive to treat. In Kenya, high levels of flouroquinone resistance of a bacterium, Neisseria gonorrhea have been widely reported. Antimicrobial resistance may be coded on plasmids, mutational events or on transposons. A growing body of evidence indicates that metal tolerance and antibiotic resistance are often found together in many clinical isolates and that metal and antibiotic resistance is closely associated. Besides having clinical consequences, resistant bacteria of animal origin may be the source of determinants of resistance for the possible transfer to human strains. Most of the previous studies have concentrated on clinical isolates from human and animal stools while studies targeting environmental isolates are limited. This study aimed at identifying fecal indicators and pathogens recovered from wastewaters used to clean animal carcass and sludge used as manure, from cattle slaughterhouse in Kayole and the separate sheep and goat slaughterhouses both in Kiamaiko, Nairobi and to determine susceptibility of isolated bacteria against 13 antibiotics and 6 heavy metals, in addition to studying plasmid profiles. Isolation of fecal indicators and pathogens was carried out using standard laboratory methods. Sensitivity to antibiotics was determined by the agar diffusion technique on Mueller-Hinton agar. Heavy metals tolerance was determined by well diffusion and tube dilution methods. Plasmid DNA was isolated using the alkaline lysis method. The fecal bacteria load was found to be 6.2 x 106, 5.3 x 105, 2.5 x 104, 2.9 x 104 and 5.0 x 106 CFU/100 mL for fecal streptococci and 3.4 x 105, 4.1 x 103, 3.0 x 104, 2.7 x 103 and 3.9 x 105 MPN/100 mL for fecal coliforms in cattle wastewater, cattle sludge, goat wastewater, sheep wastewater and a mixture of goat and sheep sludge, respectively. Pearson correlation analysis showed positive correlation between prevalence of fecal streptococci and fecal coliforms (r=0.931 at 0.01 level). Vibrio and Salmonella species were more frequently detected in samples which also showed high incidence of indicator organisms. There was high resistance to lincomycin (90 %), ampicillin (80 %) and methicillin (72.5 %) and low resistance to chloramphenicol (22.5 %). Another potential environmental threat noticed was heavy metal tolerance of the indicator organisms and pathogens to nickel, mercury, copper, zinc, lead and cobalt. Results of the test of toxicity in solid media agreed with those in liquid, however, inhibitory concentrations in solid media were much higher compared to those in liquid. Lead and nickel were the least toxic metals. Mercury was the most toxic component for all bacteria, followed by cobalt and then copper. Among the 40 bacterial isolates studied only 18 (45%) harbored between 1 - 2 kb plasmid DNA bands which ranged in size from 4kb to 10kb. The results showed the dynamics of resistance development in warm blooded animals usually used or consumed by humans. This study provided data on the level and risks of microbiological contamination as well as baseline data for the future assessment and monitoring of pollution levels of wastewaters. With regard to the high contamination level of the wastewaters and sludge with resistant bacteria as revealed in this study, treating of wastewaters and sludge is recommended, before using or discharging them into the environment and also proper use and disposal of antimicrobial agents. The metal-antibiotic double resistance detected in this study call for intervention measures to curb the potential health hazard that heavy metal pollution pose in the environment.
Antibiotic susceptibility and genotypes of escherichia coli isolated from HIV Sero-positive adults at Mbagathi district hospital, Nairobi
(2013-08-14) Emacar, Jacinta
Persons living with HIV may succumb to acquired immunodefiency syndrome (HIV/AIDS), which renders them susceptible to opportunistic infections. Several antibiotics are recommended for prophylaxis and treatment of the infections. These usage of antibiotics has lead to the development of multi drug resistant strains of Escherichia coli isolated from the gut of persons living with HIV/AIDS (PLWHA). Such resistance is of great concern as the organisms may become infectious and also serve as an important reservoir for resistant genes which can be transferred to potential pathogens. Available antibiotics would be rendered ineffective thus plugging the country into a possible post antibiotic resistance era. This study was carried out to determine the antibiotic susceptibility and genotypes among fecal E. coli isolates from PLWHA who were reporting at Mbagathi District hospital. E. coli were obtained by culturing stool samples from the study population on MacConkey agar and the isolates biochemically identified. The isolates were tested for antimicrobial susceptibility to commonly used antimicrobials using Kirby Bauer disk diffusion method and the E-test. Out of the 216 (81.81%) isolates from PLWHA and taking antibiotics (HIV+A+), 209 (96.76%), 198 (91.67%) and 188 (87.04%) isolates were resistant to trimethoprim-sulphamethazole, tetracycline and ampicillin respectively. The results also indicated that isolates from this group were highly resistant to cefuroxime and augmentin (51.39% and 58.33%).
Antimicrobial activity of selected plants used by traditional medical practitioners in Keiyo district, Kenya
(2011-12-05) Ruttoh, Ernest Kiprono
Human health is faced with many challenges caused by microbial infections. The situation has been worsening over time due to several factors which include emergence of new infectious diseases. The Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome and development of drug resistance by microorganisms has also contributed a lot to the problem facing human health. In Kenya, use of medicinal plants to treat various ailments, including infectious diseases, has been going on from time immemorial. Scientific data on the efficacy and safety of these plants are insufficient. Screening of plant extracts for pharmacologically active agents has also lead to the discovery of many clinically useful drugs. These spur the need to continuously carry out research with the aim of finding alternative antimicrobials. The current study was aimed at assaying extracts from selected medicinal plants used to treat infectious diseases by Keiyo community against some selected microorganisms. Methanol extraction of all the plants studied was done and sequential (hexane, dichloromethane, ethyl acetate and methanol) and alkaloid rich portions of Tabernaemontana stapfiana was carried out. The extracts of stem bark, leaves and root bark were screened against reference strains and local clinical isolates including bacterial strains of Salmonella typhi, Pseudomonas aeruginosa, Klebsiella pneumoniae, Enterococcus faecalis, Bacillus subtilis and Staphylococcus aureus. Fungi were also sreened, including yeast strains of Candida albicans and Cryptococcus neoformans and filamentous fungal strains of Trichophyton mentagrophytes and Microsporum gypseum. Multiple-drug resistant strains (MDRS) of Staphylococcus aureaus and Klebsiella pneumoniae were included. Minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC) of the active extracts were determined. The methanol extracts showed good antimicrobial activity against both bacterial and fungal strains used including the multiple drug resistant Staphylococcus aureus strain with minimum inhibitory concentrations ranging from 15.6 to 8000 µ/ml and minimum bactericidal/fungicidal concentrations ranging from 31.25 to 8000 µg/ml. The sequential extracts of T. stapfiana had a better antimicrobial activity with minimum inhibitory concentrations (MICs) ranging between 3.9 and 500 erg/ml and minimum bactericidal/fungicidal concentrations (MBCs/MFCs) between 7.8 and 2000 µg/ml against the tested microorganisms. However, the alkaloid rich fractions exhibited reduced antimicrobial activities as compared to methanol and sequential extracts with MICs and MBCs values ranging between 15.6 and 2000 µg/ml and 31.25 and 2000 µg/ml, respectively. The phytochemical screening showed the presence of various classes of compounds. There was presence of alkaloids and saponins in T. stapfiana methanol and sequential extracts. The alkaloid rich fraction did not have saponins, and therefore the lowered activity indicates a possible additive or synergistic activities of saponins and alkaloids when they are combined. Extracts from T. stapfiana and Indigofera homblei have activity against multiple drug resistant Staphylococcus aureus. Medicinal plants have a wide range of antibacterial and antifungal activities and therefore justify their usage as medicine by the local population.
The antimicrobial susceptibility pattern of campylobacter isolates from Nairobi, Kenya.
(2014-05-14) Kabiru, Pamela Pity Nyawira
Campylobacteriosis is a group of infections caused by Gram )legative rods of genus Campylobacter. It is among the most common bacterial infections of humans worldwide. Campylobacteriosis in Kenya is managed and treated presumptively according to its clinical features and manifestation. The common antimicrobial drugs used are: fluoroquinolones, macrolides and quinolones. Indiscriminate use of these drugs may lead to development of antimicrobial resistance. The main objective of this study was to investigate the antimicrobial susceptibility pattern of Campylobacter in Aga Khan University Hospital, Nairobi, Kenya. Four hundred and forty seven (447) diarrheic stool samples were obtained from in and out-patients seeking treatment in the Hospital. For isolation of Campylobacter, stool samples were cultured onto blood-free selective Campylobacter medium. The isolation rates of bacterial pathogens were 29 (6.5%) for Campylobacter species. Other bacteria isolated were Shigella, Salmonella and Enteropathogenic Escherichia coli. The Campylobacter isolates were characterized to species and sub-species by colonial morphology, staining, motility and Analytical Profile Index (API) Campy strip tests. Out of 29 Campylobacter isolates 28 (96.6%) were C. jejuni and one (3.4%) was C. colLThe proportional distribution of C. jejuni bio-type 1 accounted for six (20.7%) while bio-type 2 accounted for 23 (79.3%). There was significant difference between isolation rates of Campylobacter across the age groups (X2 = 8.825, p = 0.032. There was no significant difference in isolation of Campylobacter between males and females (X2 = 0.534, p = 0.465). Out of the 300 samples that had invasive infection 15 (5%) were due to Campylobacter. Antimicrobial susceptibility testing was performed by disk diffusion method and by E-test system according to Clinical and Laboratory Standards Institute (CLST). The study fmdings showed that there was no resistance to azithromycin, chloramphenicol, gentamicin and doxycycline. Resistance to ciprofloxacin was detected in four (13.8 %), ampicillin two (7.1 %), nalidixic acid three (10.3 %), cotrimoxazole 23 (79.3 %). Cross-resistance was detected between ciprofloxacin and nalidixic acid and between cotrimoxazole and ampicillin. Beta-lactamase production was detected in 75.5% of the isolates. The results of this study showed that the prevalence of Campylobacter in the patients from Aga Khan University Hospital was 6.5%. There was detection of resistance of the Campylobacter isolates to some antimicrobial drugs commonly used. Beta-lactamase production occurred in many isolates. It is therefore important for the treatment of Campylobacter to be instituted only after susceptibility testing has been done.
Aspergillus flavus and aflatoxin levels in stored maize in Eastern Kenya and Antifungal activity of some plant extracts
(2011-05-09) Kiswii, Muange Theddeus
Maize is the staple crop in Eastern Province of Kenya especially in Makueni, Kangundo, Kibwezi, Machakos and Kitui South Districts. It has been noted that the abiotic and biotic stresses associated with these Districts promote growth of toxigenic fungi that produce mycotoxins in maize in storage. The aflatoxin producing species of Aspergillus are a common phenomenon in maize contamination that has led to frequent outbreaks of aflatoxicoses in these regions. To address this problem, this study w as carried out between September 2007 and June 2008 to evaluate the incidences of A. flavus, determine the aflatoxin levels in stored maize from 5 Districts and evaluate the efficacy of 15 selected medicinal plants collected from Mwingi District. Four Aspergillus sp. that included A. flavus, A. niger, A. ochraceous and A. tamarii were isolated from maize collected from the 10 Divisions in the 5 Districts. Machakos (mean 58 80%), Kangundo (mean 58.4%), and Kitui South (mean 54.80%) Districts had significantly (P < 0.05) high incidences of total Aspergdlu.s sp. than Makuem (mean 45%) and Kibwezi (mean 24.20%). The incidences of A. flavus from the 5 Districts and the 10 Dix isions indicated a significant difference (P < 0.05). Kangundo District (mean 31.71%) liad the highest incidence of A. flavus while Machakos District (mean 12.92%) had the lowest. Among the 10 Divisions, high incidences of A. flavus were found in Matunguht (mean 33.18%), Kaiti (mean 32.6%) and Kangundo (mean 30.25%) Divisions. The love cst incidence was detected in Kathiani Division (mean 10.82%). Out of the 10 samples analyzed, 2 samples had > 50 ppb, 5 had > 20 ppb and the remaining 3 had < 20ppb of aflatoxin (AF) levels. The highest AF levels were recorded in samples from Kibwezi (60.35 ppb) and Kathiani (50 ppb) Divisions while the lowest was found in Kangundo (Oppb). I 'lie methanol leaf extracts of the 15 plants were evaluated for antifungal activity against A. flavus at different concentrations of 1000mg/ml, 750mg/ml and 400mg/ml rising Agar Well Diffusion Method. Plants found to have inhibition zones of more than 1Omm at 400mg/ml had their bark assayed for antifungal activity. Both the mcthanolic leaf and bark extracts of the fifteen plants assayed displayed concentration depended antifungal activities that were comparable to that of the reference drug Miconazolc at IOmg/ml. The leaf extracts showed better antimicrobial activities than the bark extracts. For the leaf extracts, Boscia coriacea (mean 17.40mm) had the highest zone of inhibition followed by Zanthoxvlem chalybeum (mean 17.20mm). For the bark extracts, Crown megalocarpus (mean 15.Omm) recorded significantly high antifungal activity while 77thonia diversfolia (mean 13.Omm) had the lowest at 400mg/ml. Both the leaf and bark extracts that were found to be effective were assayed for minimum inhibition concentrations (MIC) and minimum fungicidal concentrations (MFC) using broth (SDB) microdilution method. Senna stamea had the lowest MIC and MFC of 6.25mg/ml and 12.51ng/ml respectively. The preliminary phytochemical analysis of the effective plants revealed the presence of bioactive compounds that included tannins, saponins, flavonoids, terpenoids, cardiac glycosides and alkaloids. The results obtained from the study could be used as a viable management strategy against A. flavus.
Assesment of Carbon Sequestration and Biomass Accumulation of Managed and Natural Mangrove Plantations of Mida Creek, Kilifi County Kenya
(Kenyatta University, 2021) Omollo, Kevin, Ogolla; Najma Dharani; Benards Okeyo
Mangrove forests play a significant role along the coastal environment throughout the tropical coast. They provide ecosystem services that are able to sustain both flora and faunal organisms found in such ecosystems. They are stores of large quantities of carbon in their biomass hence referred to as carbon sinks. This carbon can be emitted into the atmosphere when mangrove forests are degraded through unsustainable utilization. With accurate quantification of carbon stocks in these forests, it will be easy to define their potential role in global climate regulation through their carbon sequestration ability. Since the sequestration potential of the replanted managed mangrove species of Mida Creek is unknown, this indicates an information gap which calls for bridging to help develop a baseline inventory data for effective forest conservation and management. The main objective of this study is to quantify the amount of carbon sequestered by the managed mangrove forest of the Mida Creek, Kenya. Three sites were selected for this study; 15 year-old Kibusa Plantation, 20 year-old Green Island Plantation, and a Natural Stand. Fifty Plots in the plantations and sixty plots in the natural stand of (10 x10) m2 were selected in each study site. Three carbon pools were investigated; aboveground carbon, belowground carbon, and soil organic carbon. Biomass for carbon determination in Kibusa and Natural Stands was estimated using a general allometric equation. Aboveground carbon was determined by measuring the diameter at breast height using a DBH meter. Belowground biomass and soil organic carbon was determined through root coring method using a soil corer at different depth profiles. Mean total carbon stocks in Kibusa and Green Island Plantations was 424.52±11.68 Mg C/ha and 958.57±50.01 Mg C/ha while the natural stand contained significantly higher total Carbon stocks of 2159.77±31.09Mg C/ha. There was no significant difference in the amount of soil organic carbon among the three different sites (F0.05(1)2,15=0.35, p>0.05). This study indicates that reforestation enhances structural development of replanted mangroves and that replanted mangroves are significant carbon stores. Rhizophora mucronata species was found to be the most abundant species compared to all the other species in all the three study sites, with an Importance Value Index of 117.1. In addition, Ammonium, Phosphates and Nitrates from the soil were also determined. Ammonium was the most abundant nutrient in all the three study sites. High Ammonium concentration in the mangrove sediment led to high amount of carbon sequestered in the root biomass. Therefore high ammonium concentration in the soil leads to increase in amount of carbon sequestered in the root biomass. From these results, we can deduce that awareness should be raised among the community members on the need for conservation and reforestation that will increase the amount of carbon sequestered since more mangroves increase the amount of carbon (IV) oxide capture. This will help in mitigating the issue of global warming at local levels.
Assessing photovoltaic solar energy financing models and Sustainable energy transition in Ngaciuma-Kinyaritha subcatchment, Kenya
(2013-08-14) Nkpeebo, Amos
Solar energy is deemed the single energy resource that is continuously decreasing in price (by 75%), increasing in utility and could effectively contribute to sustainable watershed management. In Kenya, there is an observed acceptance of Photovoltaic (PV) Solar Home Systems (SHS) as the best-fit form of energy to meet rural energy demand. This could potentially displace rural predisposition to woodfuels and paraffin and cumulatively, reduce environmental vulnerability. Photovoltaic SHS are nonetheless challenged mainly by the initial capital cost disbursement, globally and in Ngaciuma- Kinyaritha sub-catchment, Kenya. The focus of this study was to evaluate the economic and environmental significance of different solar energy financing models. It also aimed to analyse different scenarios in order to determine the most cost effective, most sustainable and best-fit financing models that together overcome the capital up-front of solar energy accessing in Ngaciuma-Kinyaritha sub-catchment. In achieving the stated objective, the study adopted and adapted interplay of quantitative and qualitative tools of data collection and methods of data analysis to establish the relationship between energy use and environmental degradation and the ability of households to transition into solar energy use. The study made use of empirical survey instruments including: structured questionnaires (100 cases - using households as a sampling unit), Focused Group Discussions (in the upper, middle and lower zones of the sub-catchment) and interview guides for three selected institutions. The analysis of data followed an objective-based approach in order to emphasize the field observation under each key objective. In analysing the field data, the study made use of simple analytical tools comprising: descriptive statistics (frequencies, percentages and means), chi square analysis, cost benefit analysis, PESTELI analysis, scenario analysis and data triangulation. Using cost benefit analysis, the study perceived a payback period of 6years for SHS that are 50watts and a life payback of 8,685Ksh. It also recorded a payback period of 8years for systems that range between 200wats and 1kilowatts and a life payback of about 100,000Ksh. On the average, the ability to pay for SHS under the cash sale financing model, third party credits model and the solar developer model was observed to be 200Ksh. Using scenario analysis, the study indicates that willingness and ability to pay for multiple utility SHS under the solar developer model is relatively higher than the cash sale model which is the observed status quo in the study area. In a PESTELI analysis, the study perceived a tenable potential in rural energy supply and recommended that an energy user remodelling should be undertaken by the Kenya’s energy ministry to foster energy transformation in Ngaciuma-Kinyaritha sub-catchment. It also recommended that the Ministry of energy (MOE) in collaboration with Global Village Energy Partnership (GVEP) could pilot alternative capacity building scenarios in rural energy use. Finally it gives specific strategies which could be used to improve upon sustainable energy use in Ngaciuma-Kinyaritha Sub-catchment and across the developing world.
Assessment of Germination Potential and Population Status of Melia Volkensii Gürke in Kitui County, Kenya
(Kenyatta University, 2022) Njehu, Jane Mukami; Emily Wabuyele; Adelaide Mutune
Melia volkensii Gürke is a native tree species that grows in the arid and semi-arid areas of East Africa. There has been overutilization of this tree which may lead to risk of rapid decrease in its community and genetic diversity. Additionally, planning and implementing planting programmes and conservation plans of M. volkensii have been hindered by insufficient knowledge on its seed storage behavior. This study sought to develop optimal protocols for seed germination and assess population status of Melia volkensii to enhance conservation and supply chain management in Kitui County. Melia volkensii fruits were collected from Tiva Forest and the germination experiment was carried out in KEFRI Kitui within nursery conditions. Seed germination experiments were arranged in a completely randomized design with three factors – extraction state, storage container and storage temperature. For extraction, seeds were divided into two lots – extracted seeds and unextracted seed (nut). Two types of storage containers were used namely sealed and unsealed. The storage temperatures were room temperature (30oC) and cold storage (-20oC). Germination tests were done before storage, and later after 2, 4 and 6 months in storage from each of the storage conditions. A hundred seeds and nuts each were sown for each experimental unit. The rate of seedling sprouting was recorded for a duration of 10 days as a percentage of seeds sown. Variation in germination percentages “was tested using two-way analysis of variance (ANOVA) at 95 % confidence interval and means separated using fisher’s protected least significant difference” in R and SAS statistical software. The highest percentage (89 %) was scored in nuts kept in unsealed containers at 30oC at 6 months and the lowest (14 %) in seeds stored in similar conditions for 2 months.The differences were significant. These results indicate that the germination rates of M. volkensii seeds increased with increase in period of storage. Additionally, plant population was determined in situ across seven transect lines measuring 1050 meters in length. Sampling was carried out in five plots measuring 50 x 50 m established at intervals of 200 meters. Transect 1 and 7 were laid in farmland while the transects between these two were laid in bushland. All tree species represented in each plot were counted. “Height and diameter at breast height (DBH) were measured for all M. volkensii trees within the plots. Melia volkensii seedlings and coppices were counted in 5 x 5 m nested plots within the larger plots. One-way analysis of variance (ANOVA) at 95 % confidence interval was used to test for variance in parameters measured and means separated using Tukey’s HSD. There were significant differences in height and DBH” means of M. volkensii among transects. Transect 2 had the lowest mean height and DBH while the tallest trees were in transects 1, 3, 4, and 6. Transect 1 had highest mean DBH. Means of seedlings were not significantly different among transects. Coppicing was significantly highest in transects 1 and 4. Moreover, relative abundance, species richness and diversity of plant species observed were analyzed “using Simpson’s index of biodiversity and Shannon-Wiener species diversity index. Melia volkensii was the most frequently occurring species with 12.2% (n=67) followed by Acacia tortilis10.0 % (n=55). Calotropis strophela, Commiphora capensis, Maerua crassifolia were the least represented relative abundance of 0.18 %. Values of indices used varied among transects and did not follow the location of transect implying that diversity was not determined by land disturbance. In conclusion, nuts stored unsealed at room temperature have the highest longevity. Based on diversity and relative abundance of M. volkensii and associated tree species in the study area, tree exploitation in Kasaala Location does not cause depletion of M. volkensii.
Assessment of Satisfaction with Postnatal Care Services Among Women Who Delivered In Embu Hospital, Embu County, Kenya
(Kenyatta University, 2021) Wachira, Joyce W.; Harun Kimani; George Otieno
Satisfaction among patients has progressively been acknowledged as a salient outcome within the delivery system of health care and there are numerous studies being done among developing countries. Majority of the women report low satisfaction with the postnatal care services compared to the other maternity care phases. The World Health Organization advocates that the women‟s satisfaction should be surveyed as a tool geared towards improvement of effectiveness and quality of maternal health care. The purpose of the study was assessment of satisfaction with the postnatal services offered in Embu Hospital among women who delivered in this facility. This study was directed by the following specific objectives; determining women‟s satisfaction with postnatal care services, determining influence of socio-demographic factors on women‟s satisfaction with postnatal care, establishing health system factors influencing satisfaction of postnatal women and establishing the influence of perceived quality of care on women‟s satisfaction. Research design used was descriptive cross-sectional. The population studied were postnatal women 15-49 years who had delivered in Embu hospital. The study applied systematic random sampling method and the sample size was 225 respondents. A structured client exit questionnaire, interviews with key informants and focused group discussion guide were used to collect data. Pretesting was done in Chuka hospital to ensure validity of the instruments. Reliability of research tools was decided through test-retest strategy. Authority to conduct this research was obtained from the Kenyatta University Ethical Review Committee and approval acquired from the National Commission for Science, Technology and Innovation. The study generated both quantitative and qualitative data. The statistical package for social scientists (SPSS version 20) was used for data coding and entry and analysis through descriptive and inferential statistics. Percentages, frequencies and cross tabulations were adopted to present data. The study outcomes uncovered that most women 54.6% were satisfied with postnatal care services provided with only 45.4% being dissatisfied. Findings from this study also showed that socio-demographic factors like age (P=0.759), marital status (P=0.667), education level (P=0.717), occupation (P=0.194) and monthly income (P=0.385) did not have a significant relationship with women‟s satisfaction with postnatal care. The study noted that the health system factor that influenced postnatal women‟s satisfaction was comfort and care (P= 0.008). Pertaining influence of perceived quality on satisfaction, it was noted that women from the FGD‟s associated quality with tangibles like clean hospital environment, availability of resources and staff. Majority of the key informants ranked the quality of postnatal services as good. The study concluded that some women 45.4% were still dissatisfied with the postnatal care services provided in this facility. The study recommends that the county government in liaison with the hospital administration should have frequent patient satisfaction surveys which can help to provide feedback to customers hence improving the satisfaction of the clients. Recruitment and employment of more qualified staff by the county government to enhance the quality of postnatal care provided.
Assessment of the role and impact of agroecosystem diversification on maize stemborer, leucaena psyllid and their natural enemies at the Kenyan Coast
(2013-01-24) Midega, C. A.O.
Lepidopteran stemborers are a major constraint to the production of cereals in the tropics with Chilo partellus (Lepidoptera: Crambidae) being the most serious species. The pest is an exotic species that originated from Asia. Chemical control of the pest is unpractical and can only be effective during a limited period when the first and second larval instars are feeding on the leaf tissues after which they bore into the stem. Classical biological control using parasitoids and predators in an agroecosystem was considered to provide prospects of additional protection to cereals. Leucaena is an essential leguminous agroforestry tree species with several used besides alley cropping. Leucaena psyllid is threatening the future use of leucaena as an agroforestry tree. Classical biological control using exotic parasitoids has been tried but their establishment and efficacy had not been determined. The current study assessed the role of agroecosystem diversification as a way of promoting the numerical and functional levels of the pests' natural enemies. Studies were conducted at Mtwapa in Coastal Kenya and spanned over a period of 4 cropping seasons. Treatments consisted of hedgerows of leucaena only, gliricidia only, alternating rows of leucaena and gliricidia, and four plots without trees. During the cropping seasons, maize was planted between the hedgerows while a row of cowpea was planted between the rows of maize. Foliar sprays of malathion to control the psyllid were applied on one of the leucaena only hedgerow. One of the plots without trees was planted with an intercrop of maize and cowpea. The remaining three plots without trees were planted with maize alone and one of them procted from attack by stemborers by use of Bulllock (betacyfluthrin) granules. The treatments were laid out in a randomised complete block design and replicated four times. Mean rates of egg parasitism were found to be high (>70%) while larval and pupal parasitism rates were low (10%) for all the treatments. These rates however did not support the enemies hypothesis (neutral response), indicating that the vegetation structures and cultural treatments established in the study did not of enhance the activity of the egg, larval and pupal parasitoids. Predation rates were generally low in all the treatments (6.13%) with no significant difference among the treatments to support the natural enemies hypothesis. Thus, immigration into, retention and efficacy of predators were not influenced by the vegetation structure. Mean larval and pupal mortality rates were low in all the treatments, ranging from 4.8 to 9.6%. Some of the larvae and pupae under this category had a characteristic common dark coloration on the entire body, Suggesting that the mortality factor in this case was associated with microbial agents. These rates however had no significant difference pattern to support the notion that agroecosystem diversification leads to higher natural enemy levels and efficacy. Life table analyses results show no conspicuous natural enemy activity in the more diverse cropping systems as there were no marked variation in intergeneration and mean real generation maortalities among treatments. The main mortality factor was 'disappearance', which represented mortality caused by factors other than parasitoids. Both Tamarixia leucaenae and Psyllaephagus yaseeni were recovered at every sampling occasion parasitising the leucaena psyllid, indicating their successful establishment since they are present in the field. The parasitism indices obtained showed that the parasitoids had a significant impact on the pest, though not offering effective control. In spite of this, they certainly contribute towards the overall aim of reducing and keeping under check the pest levels.
Association of heavy metal tolerance with multiple antibiotic resistance in bacterial isolated from wetlands of lake Victoria basin Kenya
(2011-05-09) Sikuku, Mutuku Christopher
A study was carried out to determine the heavy metal concentrations in the wetlands of Lake Victoria basin and their effect on bacterial resistance to ten commonly used antibiotics. Water and sediment samples for heavy metal analysis and microbiological assays were randomly collected from sewage outfalls and points bordering heavy metal activity settlements. Heavy metal analysis was done using flame Atomic Absorption Spectrometer (F-AAS). The microbiological assays targeted heterotrophic bacteria, coliforms and enteric pathogens. The isolates were subjected to heavy metals;- mercury, nickel, chromium and copper in the laboratory to assess their levels of tolerance. Antibiotic susceptibility testing was carried out to check for antibiotic resistance. Sediment samples recorded a higher level of heavy metals with a mean range of 31.97109.9, lead; 3.48-183.66, zinc; 3.01-17.03, nickel; 1.93-214.61. copper; 17.01-65.91, cobalt; and 2.08-25.89 mg/g chromium compared to water samples whose mean range was as follows;- lead; 0.77-0.94, manganese; 0.10-3.10, zinc; 0.23-1.16, cadmium 0.020.04, and copper 0.51-0.57 mg/1. There was a significant relationship in the amounts of heavy metals in water samples and the bacterial counts, r = 0.637, p < 0.05. The study showed a significant difference in percentage tolerance to the four, heavy metals tested. (f = 4.25, P = 0.011, P < 0.05). Mercury recorded the highest toxicity followed by chromium and nickel. Copper was the least toxic to the microorganisms. 53.8% of the total isolates showed multidrug resistance. They were significantly resistant (p < 0.05) to cefuroxime (67.7%), cotrimoxazole (65%), tetracycline (62.4%) and ampicillin (53%). They were however highly sensitive to, gentamycin (98.9%), kanamycin (83.9%) and norfloxacin (79.6%). The study showed no significant difference in multidrug resistance in the three bacteria groups (F =1.75 P = 0.191 P > 0.05). however er, multidrug resistance in the enteric pathogenic bacteria (mean % multi drug resistance 65.15%) was higher than in heterotrophs (mean 46.52%) and coliform bacteria (mean 6.36%). There was a significant relationship between chromium tolerance with resistance to cefuroxime (p < 0.000), Nickel tolerance with resistance to cefuroxime (p < 0.05) and mercury tolerance with resistance to ampicillin (p < 0.05). Plasmid DNA finger printing of the metal tolerant and antibiotic resistant isolates showed a positive relationship in number of isolates carrying plasmids and the number having multiple drug resistance (r = 0.372, P = 0.261) suggesting that heavy metal pollution in wetlands induces multidrug resistance. The high degree of resistance to common antibiotics like ampicillin, cotrimoxazole and cefuroxime can therefore be attributed to the inflow of heavy metal rich effluent into the wetlands of the Lake basin resulting to co-selection of both metal tolerant and antibiotic resistant microbial species. This requires intervention measure s to curb the potential health hazard posed by heavy metal pollution in the aquatic ecosystems.
Bacteriological and physico-chemical quality of water from various sources in Samburu District and efficacy of selected plant products in water purification
(2012-04-17) Kipkemboi, Cheluget
Limited access to safe drinking water and information on water quality in sparsely populated arid and semi-arid regions has contributed to frequent outbreaks of diarheal disease. There is therefore urgent need to determine the bacteriological and physico-chemical quality of water in various sources in these regions. This study was undertaken in order to determine water quality in Wamba Division of Samburu District and to asses the efficacy of plant extracts in purifying water. Bacteriological analyses was carried out using multiple tube fermentation technique and heterotrophic plate counts technique, while physicochemical analyses were carried out using standard methods. Qualitative bacterial determination confirmed the presence of thermotolerant eoliforms, Shigella and Salmonella spp. in most water samples examined. The same samples frequently recorded high levels of turbidity (range,S to 6100 NTU), alkalinity (range, 20 to 1577 mg L-! CaC03) and low salinity (range, 0 to 0.2 ppt). Faecal coliform load in dry river bed wells (mean 471.63) was higher than in the other categories of water sources (dams, rivers, springs and tap water). This study also found that the boreholes had the highest mean conductivity (830.8 )lS em") while wells had the widest range (4.6 to 5940.0). High levels of conductivity in water from groundwater sources can be attributed to the long period of contact between the water and mineral sources. Water treatment with alum, sodium hypochlorite and extracts from Boscia coriacea Pax. Maerua decumbens (Brogn.) Dewolf roots and Moringa oleifera Lam. seeds resulted in a varied reduction of bacterial and sediment loads of the water samples. Overall, all the treatments were found to be effective in reducing bacteria and sediment load in water samples collected from various sources, except for some unidentified residual bacteria that resisted the disinfection properties of plant extracts. Changes in the percentage load of heterotrophic plate counts (HPC) among the treatments used differed significantly (P < 0.05, DF = 5). Overall mean percentage change in HPC were 26.51, 46.00, 30.20 and 14.50 for M Oleifera Lam., M decumbens, B. coriacea and the control respectively compared to 74.76 and 90.95 in the case of alum and sodium hypochlorite in the same order. These values indicate that changes in bacterial density during water treatment may be due to loss of viability or alteration in eulturability. Results obtained in this study further indicated that there was no significant difference in water turbidity reduction (P < 0.05) by M oleifera, M decumbens and B. coriacea. Both B. coriacea and M decumbens chelants resulted in a high removal of the initial turbidity by 50.36 % and 43.87 % respectively during 30 minute treatment period while M oleifera were 40.53 %. As such the three species can be considered potentially useful chelants, and should be subjected to further study. During this study, it was noted that, plant extracts changed the water pH. This observation suggests that pH change possibly plays a vital role in inactivating bacteria in water. Bacteriological water quality analyses revealed that water from most sources had bacterial loads that exceeded the WHO value/guidelines for drinking water. Isolated species of E. coli, Salmonella and Shigella spp from water samples also showed varied antibacterial sensitivity to crude plant water extracts. This study therefore concludes that water from most sources is contaminated and must therefore be treated before consumption. It is recommended that further studies be conducted to identify the mechanism and active ingredients present in the plant extracts responsible for reducing sediment and bacterial load in water and how their efficacy is affected by the physico-chemical properties of water.
A biological control approach of armillaria root rot of tea
(2012-06-14) Onsando, James Micah
Field, greenhouse and laboratory experiments were conducted between June 1987 and September 1991 to investigate: (i) effects of soils amended with locally available organic agricultural wastes (ii) effects of sub-lethal doses of basamid (iii) effects of commonly used inorganic fertilizers in tea (iv) effects of age and surface area of coffee pulp (v) effects of soil moisture in coffee pulp amended soil on the proliferation of Trichoderma spp. in Kenya tea soils (vi) antibiotic activities of Trichoderma spp. in Kenya tea soils on Armillaria mellea and (vii) the potential of coffee pulp in the management of Armillaria root rot of tea. The organic amendments, saw dust, coffee pulp and husks in a 10:1 ratio, filter press cake, cow manure, sheep manure and goat manure in this study influenced the population dynamics of soil microorganisms differently both in the greenhouse and field. Coffee pulp and husks significantly (p=0.05) enhanced Trichoderma proliferation more than the other organic amendments. The enhanced proliferation of Trichoderma spp. (T. koningii, T. harzianum and T. longibrachiatum by coffee pulp was rate dependant with 16 and 22 grams carbon giving the highest populations without significant (p=0.01) differences between them. The peak Trichoderma proliferation was on the fifth month after treatment application, implying that for sustenance of high Trichoderma populations in the soil for biological control of Armillaria root rot of tea, a second or even third application would be necessary. The coffee pulp had the added advantage of significantly (p=0.05) enhancing high proliferation of non-Trichoderma fungi and bacteria, which in turn could make synergistic antagonism against A. mellea possible. The coffee pulp and husks in a 10:1 ratio was as effective as basamid in the management of Armillaria root rot of tea in the field. Unlike basamid, coffee pulp significantly (p=0.05) enhanced tea yields. The usage of basamid at different rates, some of them sub-lethal to Trichoderma and inorganic fertilizers NPKS 25:5:5:5, NPK 20:10:10, S/A and DAP at 150kg N/ha was significantly inferior to coffee pulp in the enhancement of microbial proliferation including that of Trichoderma spp. Possible contributory factors to the superior enhancement effect of the coffee pulp to microbial proliferation include adequate food reservoir and optimal soil pH for microbial activities. Fresh and one-month-old coffee pulp and husks enhanced significantly (P=0.05) more microbial proliferation including that of Trichoderma spp. more than the older pulps. The population proliferation with age was quadratic and dependant on carbon content. Increase in coffee pulp and husks surface area, improved the material's ability to enhance Trichoderma proliferation and that of other microorganisms only for a short duration. This implies that in order to sustain high Trichoderma populations, more frequent applications of the ground coffee pulp and husks would be required than when the normal coffee pulp is used. Dry soils at 15 to 25 moisture content significantly hampered Trichoderma proliferation. Wet soils at 35 to 50 moisture content significantly (P=0.05) enhanced Trichoderma spp. proliferation. The better survival of Trichoderma spp. in very wet coffee pulp amended soils, indicated their tolerance to anaerobiosis. The results suggested therefore that for maximum biocontrol benefit of coffee pulp due to proliferation of Trichoderma, application should be restricted to very wet months of the year. Metabolites of Trichoderma isolates significantly (P=0.05) inhibited mycelial and rhizomorphal growth of A. mellea. T. koningil (isolate 9), T. longibrachiatum (isolate 3) and T. harzianum (isolate 4) had the highest antibiotic activities against A. mellea. A mixture of metabolites of the 9 isolates did not exhibit synergistic effects.
Biological nitrogen fixation in drought resistant tepary bean (Phaseolus acutifolius A. Grary var. Latifolius) in the semi-arid makueni district of Kenya.
(2012-02-07) Ongare, David; Gitonga, Nkanata Mburugu; Mwaniki, J. W.; Shisanya, C.A.
Laboratory trials were carried out to assess infectivity of tepary bean (TB) by the various selected rhizobium strains. Strains 446 and 3254 were obtained from the Microbiological Resources Centre (MIRCEN), University of Nairobi; while 578 and 579 were from Iserlohn, Germany. A local isolate, KTBI was obtained from Kiboko soils. All treatments except the nitrogen treatment GUNF and the control nodulated under greenhouse conditions, though there were variations in the proportions of modulated plants. The highest nodulation proportion (100%) was observed with strain 3254 followed by 446 (75%), then 578 and 579 (both at 25%). The lowest nodulation proportion was observed with strain KTBI (20%). Field trials were conducted at KARI/ICRISAT station; Kiboko to compare the dry matter yields of tepary bean inoculated with various rhizobial strains. Plants were sampled at three stages during growth and separated into several fractions viz. root, shoot and nodules. There were no significant differences in the dry weight and mean pod dry weight from treatment 32543 were significantly higher (p<0.05) than for all the other treatments. Sample diffusive resistance readings were high in TB (about 0.17) compared with indigenous crops such a maize (0.150). This was indicative of good water economy by the plant as exemplified by the corresponding low relative transpiration rates. DNA samples from the various treatments did not give good amplification due to the scarcity of specific primers. However, one primer produced good amplification revealing a close phylogenetic relationship between rhizobial strains 578 and 579 due to the similarities of their bands while strains 3254, 446 and KTB 1 had quite dissimilar bands. N analysis was carried out at the division of environmental and applied biology, University of Dundee; both the % N (2.55) and mean N per plot (19.26g) for treatment 3254 were significantly higher than for all other treatments. All data processing was carried out using the Microsoft Excel and means separated using Turkey’s procedure.
Carbon sequestration potential of rehabilitated and natural forest sites of bamburi cement limited, Mombasa County, Kenya
(Kenyatta University, 2015-10) Mwikamba, Edward Mutwiri
Deforestation in the tropical regions accounts for approximately 20% of carbon dioxide (CO2) emissions to the atmosphere. Restoration of mined areas through afforestation/reforestation (A/R) can potentially capture large quantities of atmospheric carbon dioxide if appropriate management strategies are applied. This will help reduce the rising CO2 levels in the atmosphere. The key challenge for successful implementation of A/R carbon project is the unreliable estimation of biomass carbon stocks in forests to find out their relative carbon accumulation potential. Bamburi Cement Limited (BCL), through its mining and cement production is a substantial CO2 emitter in addition to land degradation and transformation. To counter this, the company initiated quarry rehabilitation project through replanting of Casuarina equisetifolia and Conocarpus lancifolius to reduce their carbon footprint and conserve biodiversity. Despite their importance, carbon stocks in these rehabilitated forest sites have not been quantified to determine their potential in carbon offset. The current study aimed to estimate total carbon stocks and sequestration potential in natural and rehabilitated sites of BCL in Mombasa. Six carbon pools including aboveground biomass, belowground biomass, herbaceous biomass, litter biomass, deadwood and soil organic carbon were sampled in 137 plots of 10 x 10 m. One way ANOVA and t – test analysis were carried out using MINITAB software (version 14) to compare carbon means in different sites and forest blocks respectively. The average carbon density for BCL was 126.4±9 Mg C ha-1 with a range of 52.24 to 177.42 Mg C ha-1 and was within the range of tropical forests of 120 Mg C ha-1. Aboveground biomass carbon pool stored the highest carbon stock (58%) followed by soil organic matter (25%), then belowground biomass carbon with 8%, litter carbon pool 5%, deadwood biomass carbon 3% while herbaceous biomass carbon contributed the least (0.2%). Rehabilitated areas had more carbon stock compared to natural lands. The carbon densities in the rehabilitated sites increased with increase in stand age. The results show that, with better forest management practices, quarried areas can be carbon storage hotspots hence contributing to climate change mitigation. It is recommended that harvesting of mature trees and improved management of the rehabilitated areas be adopted to increase carbon capture and storage. In addition, further research needs to be carried out on net ecosystem carbon balance and developing species specific allometric equations is recommended to upscale the findings of this study.

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