Department of Biological Sciences

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Abundance of root-knot nematodes in the University of Embu
(University of Embu, 2019) Oduor, Joseph Odingo
Root-knot nematodes are parasitic microorganisms that attack the roots of almost all species on plants. They cause devastating effects on important crops throughout the world. The aim of this study was to evaluate the abundance of root knot nematodes in different crop fields in University of Embu. Different crop fields were identified and 10 crops were uprooted randomly and rated for galling severity using a scale of 1 to 9. Differences in galling severity between different were compared using analysis of variance using R statistical software. Means were separated using Tukey’s test. There was a significant difference in galling severity between the plants with spinach and tomato having the highest rate of galling severity. The results indicate that nematode management strategies should be implemented in the University.
Antibacterial Activity of Tea Senna Leaf Extracts on Standard Laboratory Bacteria Strains
(University of Embu, 2021-09) Brian, Baraka
Senna tea is a popular herbal remedy that’s often marketed as a laxative, weight loss aid, and detox method. However, there’s little scientific evidence to support the efficacy of Senna tea for most of these uses aside from treating constipation. The aim of the study is to evaluate the antibacterial activity of Senna tea leaves, stems, bark and roots for their ethno medicinal use and their activity on selected bacterial and fungal strains. The antibacterial activity of tea Senna extracts against standardized inoculums of Escherichia coli, staphylococcus aureus and Candida albicans were evaluated using the disk diffusion method. The results were obtained by measuring the clear zones that had formed around the bacterial and fungal growth of the isolates at different concentrations of the tea Senna extract. The results showed that the extract had antifungal activity against Candida albicans with the inhibition zones measuring 18mm and antibacterial activity against Escherichia coli with inhibition zones measuring 16mm. The study provides useful information and insights into antimicrobial activities on plant extract that can be used in drug development.
Antimicrobial Activity of Citrus limon on Escherichia coli Indicator Strain
(University of Embu, 2019) Mwangi, Naomi Muringo
The purpose of this research was to evaluate antimicrobial activity of Citrus limon on pathogenic bacterial species Escherichia coli. Lemon is a citrus fruit and is an important medicinal plant of family Rutacea. It is used mainly for its alkaloids that have a large spectrum of biological activity against clinically significant bacterial strains of pharmaceutical interest. Citrus juices are greatly consumed because of their nutritional value and special flavor that are beneficial for the maintenance of good health and prevention of diseases. There is an increase in antibiotic resistance by microorganisms leading to extensive research on new effective and less expensive antimicrobials from natural sources. E. coli have the genetic ability to transmit and acquire resistance to drugs which are utilized as therapeutic agents and his has been intensified by the overuse and misuse of antibiotics. There is a need to find new methods that combat the resistance of microorganisms. Lemon can be used as an alternative antiseptic against E.coli because natural products contain complex compounds that make it difficult for the microorganism to gain resistance. This study showed the antimicrobial properties of lemon extracts. Sensitivity testing of lemon antimicrobial activity was carried out using disc diffusion method to determine zones of inhibition. Minimum inhibitory concentration of the lemon extracts was determined against E.coli. The study showed that lemon juice contained strong antimicrobial properties followed by ethanol extracts then water extracts. The differences between the zones of inhibition of juice and the two extracts was significant.
Antimicrobial Activity of Emilia Discifolia Leaf Extracts Against Standard Laboratory Test Microorganisms
(University of Embu, 2021-09) . Juma, Chrispine O; Kemuma, Dorcas Ndemo
Emilia discifolia is a species of plants in the family Asteraceae and is classified as a medicinal plant due to its antimicrobial activities. The aim of the study was to evaluate the antimicrobial activity of Emilia discifolia against standard laboratory test micro-organisms and to assess the availability of phytochemical compounds. The extract of Emilia discifolia was first prepared by washing, drying and crushing it to powder. The extract was then serial diluted to four-folds. Different laboratory test micro-organisms (Candida albicans, Escherichia coli and Staphylococcus aureus) were spread plated in different media and paper disks prepared from Whatman filter paper dipped in the extract concentration and placed on plates containing different isolates. After incubation, zones of inhibition were measured and recorded. The results showed that zones of inhibition were bigger in E. coli as compared to S. aureus and C. albicans, they also displayed key phytochemical compounds found on the plant extract. Further studies can therefore be done for further knowledge on the antimicrobial activity of Emilia discifolia.
Antimicrobial Activity of Plant J Leaf and Bark Extracts Against Standard Laboratory Test Microorganisms
(University of Embu, 2021-09) Mutai, Kimunai Kipngetich
Plant extracts with medicinal value have been used to treat many diseases that can either be bacterial, fungal or parasitic among many others. The aim of the study was to evaluate the antimicrobial activity of plant J extract extracted from plant J collected in Mbeere, Embu County against Bacillus cereus, Candida albicans, Escherichia coli and Staphylococcus aureus isolates. Serial dilution was carried out to obtain different concentrations of the plant extract, for standardization of the isolates McFarland procedure was carried out within a range of 0.5- 4 and used as a reference to regulate the turbidity of bacteria suspensions. The plant extract was extracted using water as the solvent and allowing it to boil for 5-10 minutes then filtered using a filter paper. After incubation of the preferred plant extract concentration with bacteria isolates, zones of inhibition that had formed around the bacteria growth were measured and recorded. The results showed that plant J extract had antimicrobial activity on all the bacteria isolates. The study identified microbial activities of plant J as useful and can be used as a medicinal plant
The Antimicrobial Properties of Garlic Against the Common Food Spoiling Bacteria Escherichia Coli
(University of Embu, 2019) Chebet, Daisy
Garlic is known to have numerous beneficial effects for human health. However, little information is known on its mechanism of controlling microorganisms that cause human epidemics. This study aims at evaluating the use of garlic as a natural preservative and its inhibitory effect against common food spoiling pathogen Escherichia coli. The freshly collected garlic were chopped into small pieces, dried for a week and blended. 1.5g, 2g, 2.5g and 3g were soaked in equal volume of 15ml of distilled water and ethanol as a solvent in a 250 ml sterile conical flask and shaken vigorously. The crude extract was filtered and kept at o 4 C. E. coli was obtained from fecal sample from pigs in the University farm through serial dilution and spread plate methods in sterile MacConkey agar. An antibacterial activity of the individual extract was tested on the MacConkey agar by disc diffusion method. The inoculums were spread evenly over the entire surface by swabbing in the plates. Inoculated plates were allowed to dry for 10 minutes before placing the discs. Sterile paper discs (diameter 10mm) will be impregnated with different concentration of the extracts :( 1.5g; 2g, 2.5g and 3g) were soaked in equal volume of 15ml of distilled water and ethanol as a solvent in a 250 ml sterile conical flask. This procedure was done three times. The plates were incubated at 37 0 C 24hours. The zone of inhibition was then measured. Minimal inhibitory concentration was carried out by agar dilution method where concentrations of garlic extract were prepared by using dimethyl sulfoxide in the ratio of 1:1 and was diluted with equal amount of phosphate buffer saline pH of 7.0. Data was analyzed using one-way Analysis of Variance in SPSS software. This study provided an alternative natural way of food preservation against E. coli amongst the communities within and out of Embu County. It is therefore suggest that the garlic extracts can be used as potential source of natural antimicrobial compound which if applied to bakery products before it is used for commercialization in the form of nutraceutical food it will prevent proliferation of spoiling microorganisms.
Antimicrobial Properties of Kigelia Africana (Sousage Tree) Leaf Extracts
(University of Embu, 2021-09) Odhiambo, Felix Onyango
The use of Kigelia Africana also known as “Sausage tree” as a source of medicine among the Traditional African Society has tremendously been exploited in the past for their medicinal value playing a critical role in traditional human health care systems, especially in developing countries where there is limited access to allopathic drugs. The aim of the study was to evaluate the antimicrobial properties of Kigelia Africana against two bacterial isolates (E. coli and Staphylococcus aureus) and one fungal isolate (Candida albicans). Disc diffusion method was used to determine the antimicrobial activity of Kigelia Africana extract which was extracted using the water extraction method. The results were obtained by measuring the clear zones that had formed around the bacterial and fungal growth of the isolates at different concentrations of Kigelia Africana extract. The extract concentration showed no antimicrobial activity on E. coli both at low and high concentrations. the average zone of inhibition formed on Staphylococcus aureus showed a decrease in antimicrobial activity with descending plant extract concentration as compared to Candida albicans. The study provides useful information and insights into antimicrobial activities on plant extract that can be used in drug development
Antimicrobial Properties of Plant Extract K Leaf Extracts On Standard Laboratory Test Microorganism
(University of Embu, 2021-09) Akolo, Michael
Medicinal plants have played an important role in drug discovery, with many pharmaceutical products originating from plants. Isolation and characterization of antibacterial compounds are still relevant today because of the continuing development of resistance of bacteria and fungi to antibiotics. The aim of the study was to evaluate the antimicrobial activity of plant K against Candida albicans, Escherichia coli and Staphylococcus aureus isolates. Serial dilution was carried out to obtain different concentrations of the plant extract, for standardization of the isolates McFarland procedure was carried out within a range of 0.5-4 and used as a reference to regulate the turbidity of bacteria suspensions. The plant extract was extracted using water as the solvent and allowing it to boil for 5-10 minutes then filtered using a filter paper. After incubation of the preferred plant extract concentration with bacteria isolates, zones of inhibition that had formed around the bacteria growth were measured and recorded. The results showed that plant K extract had antimicrobial activity on all the bacteria isolates. The study identified microbial activities of plant K as useful and can be used as a medicinal plant
Antimicrobial Susceptibility Testing Of Neem [Azadirchta Indica] Plant Leaf Extracts against Standard Bacterial Strains
(University of Embu, 2021-09) Guyo, Abdihakim Abdullahi
Neem is fast growing tree of the mahogany family Meliaceae used in traditional medicine as a source of many therapeutic agents by many communities and grows well in tropical countries. The aim of the study was to evaluate the antimicrobial activity of Azadirachta indica against standard bacterial strains, Escherichia coli, staphylococcus aureus and Candida albicans. Azadirachta indica leaves and stem back were used in the preparation of extracts. Disc diffusion method was used to determine the antimicrobial activity of Azadirachta indica extract which was extracted using the water extraction method. The results were obtained by measuring the clear zones that had formed around the bacterial and fungal growth of the isolates at different concentrations of Azadirachta indica extract. The extract concentration showed no antimicrobial activity on E. coli both at low and high concentrations. the average zone of inhibition formed on Staphylococcus aureus showed a decrease in antimicrobial activity with descending plant extract concentration as compared to Candida albicans. The study provides useful information and insights into antimicrobial activities on plant extract that can be used in drug development.
Assessment of Bacterial Contaminants in Roasted African Sausages and Raw Salad in Embu Town and Kangaru Market
(University of Embu, 2021-09) Opala, Omondi Collins
African sausages are local popular delicacies in Kenya. Demand for these sausages has resulted in this delicacy’s vendors being on the increase. However, the health risk posed to unsuspecting consumers of African sausages sold in informal, unhygienic makeshift road-side kiosks in major cities of Kenya is largely unknown. A purposive study was designed to isolate and quantitate bacteria from raw vegetable salad and roasted African sausages sold at Embu town and nearby Kangaru market. A total of 4 samples (2 vegetable salads and two roasted African sausages) were conveniently collected from two vendors (one in Kangaru and the other in Embu town) and studied in the Research Laboratory of the University of Embu. Four genera of bacteria, namely, Escherichia coli, Staphylococcus aureus, Salmonella species, and Shigella species, were isolated from these samples in large numbers. The results affirmed the presence of bacterial pathogens in roasted African sausages and raw salad, which are potentially zoonotic to humans, sold at these two sites. Therefore, there is a need to establish these pathogens sources due to the high microbial load defined in the current study and the need for regulatory bodies to ensure that microbiological standards are prioritized by farmers and vendors in the distribution and processing of salads.
Assessment of Occurrence of Escherichia Coli from Dams at the University Of Embu
(University of Embu, 2019) Kirega, Dennis Mwangi
Water is a very important resource and therefore its quality should be monitored to ensure it is not contaminated. Water can be polluted by plastic material, chemical effluences and fecal matter. Fecal contamination from sewage linkage into water reservoirs like dams is a major issue that needs to be addressed because it affects important resources in our environment. Water contamination by fecal material can result in outbreaks of illness and renders contaminated water requiring extra processes to clean which may require an additional investment in capital. This study strives to identify which dams are polluted and whether they are fit for irrigation and for livestock rearing. E. coli occurrence in the dam water samples helps to in identification of fecal contamination as the bacteria is an indicator organism that helps in identification of pathogens associated with fecal matter contamination. The study involved the isolation and quantification of E. coli in the dam water at the University of Embu. Water samples from 3 dams at the University of Embu were collected and a colony count of the E. coli colonies isolated from the samples was analyzed to achieve the comparison of bacterial load among the dams to help evaluate which dam is most affected by pollution. This study addresses the need for clean and safe water from the dams for irrigation and livestock use. The study showed the level of pollution in the dams. The occurrence of E. coli in the water samples from the dams provided evidence of fecal contamination but the level of occurrence suggested only minimal contamination. This therefore implied that the dam water requires minimal disinfection in the form of chlorination before use for agricultural purposes.
Bacteria Isolated from Lake Magadi Soil with Potential for Utilization of Different Substrates
(University of Embu, 2020) Bett, Sylvya Chepkemoi
There is a wide distribution of soda lakes in the world, but most are found in arid and semi-arid areas. Soda lakes contain high salt concentration with a high pH. This study was done in Lake Magadi, located in the southern part of the Kenyan Great Rift Valley and it is the most hypersaline of soda lakes in the valley. Many industries are experiencing challenges with plastics they use in their processes. Disposing the plastics is the biggest challenge since they do not degrade thus causing pollution. Haloalkaliphiles can produce polyhydroxyalkanoates which is used to make alternative form of plastics which are readily biodegraded and thus reduces pollution. Polyhydroxyalkanoates products can also be recycled and this reduces the cost of production. The purpose of this study was to find out whether the bacteria found in the soils of Lake Magadi can produce metabolites of environmental and industrial importance. This was achieved by screening the soil for the halophilic bacteria with important application in industry and environment, studying their morphology, biochemical characteristics and their substrate utilization ability. Isolation was done by culture dependent method where the bacteria from the samples were grown in the oatmeal and actinomycetes media prepared in the lab. Biochemical characterization entailed identification of the bacteria’s’ Gram status. A variety of substrates were used to test the ability of the bacteria to produce enzymes that can utilize or degrade some important macromolecules, they include; starch, CMC, cellulose, lignin, tween 20, xanthan, chitin, skim milk and pectin. A total of 18 isolates were obtained and all of them were gram positive, two of them were rods while the remaining 16 were cocci. Seven isolates utilized starch, 3 were able to utilize skim milk, 5 degraded lignin, 5 utilized tween 20, 2 degraded chitin and none of the isolates was able to utilize cellulose, CMC, xanthan and pectin. This study produced bacterial isolates that can be used for further biotechnological research and also produced enzymes of important industrial applications.
Bacteria Isolates from Microbial Mats in Lake Magadi with Potential for Substrate Utilization
(University of Embu, 2019) Kathure, Maureen Kinyua
Lake Magadi is an alkaline, hypersaline environment with extreme environmental conditions that allow specific microorganisms with specific characteristics to flourish. Its pH ranges from 9-11.5, very high temperatures, high salt concentrations (Na2CO3). Despite all the extreme conditions, this type of lake is the most productive aquatic environment in the world with productivity rates greater than the mean rate for all aquatic environments in the world. They are usually characterized by the presence of coloration of water caused by different microorganisms for instance the cyanobacteria. On the other hand microbial mats are microbial communities made up of a consortium of bacteria dominated by cyanobacteria. They are usually ubiquitous in nature and are found over the sediment surface or as floating masses in marine waters, hypersaline waters, estuaries, hot springs and deep oceans. Ecological success of microbial mats and their broad array of microbial activities suggest these microbial ecosystems might be useful in bioremediation of environmental pollutants and even bio generation of useful products. Since microbial mats contain both nitrogen fixing bacteria and photosynthetic bacteria, they usually tend to be self-sufficient with few growth requirements. The study was aimed to isolate useful bacteria from microbial mats from Lake Magadi with both biotechnological and therapeutic applications. This is because some of these bacteria can produce enzymes, proteases, antitumor and even antimicrobial agents for a variety of pathogens. Microbial mats were obtained from Lake Magadi and brought to the microbiology laboratory in the University of Embu. They were then heat treated to 100°C and 120°C. They were serial diluted and cultured in both actinomycetes agar and oatmeal agar and then incubated at temperatures ideal for their growth. After incubation 19 pure isolates were obtained from the study. Out of these only one isolate was able to utilize starch and only one could utilize cellulose. Thirteen isolates utilized tween 20 and 12 could utilize skimmed milk. No isolate utilized CMC, xanthan and lignin. Most of them were gram positives and even pathogenic. Few enzymes were identified and therefore further tests and research needs to be done for these extreme environments as there is a high diversity of microbes in the area.
Beneficial or Not? The Efficacy of Ultra Violet Sterilization Chambers in Barber Shops within Juja
(University of Embu, 2019) Ndung'u, Ian Daniel K.
Over the past few years, hairdressing, especially among men, has gained popularity and this has been attributed to the increase in disposable personal income and peer pressure among mainly the youth to conform to the latest hair fashions, generally initiated by sporting and film celebrities. Shaving is part and parcel of a man’s lifestyle and is accepted as a component of masculine grooming. This has given rise to the trade of barbering, which can be traced back even to Old Testament times (Ezekiel 5:1). It is quite usual to find a number of barber shops in major towns and cities in our world today. This has been due to the increasing demand of barbering services among men, as well as the income generated from such services. Even with the increasing popularity of barbers today, there has also been increasing cases of infection transmission through barber shops reported in several countries. This can be attributed to the very nature of shaving, which involves skin contact and use of sharp blades, making it a potential mode of infection transmission. In response to this, various techniques for cleaning and sterilization of shaving equipment have been employed, in an effort to reduce the rates of infection transmission during the process of shaving in barbershops. However, in as much as sterilization techniques are being used in barbershops, transmission of bacterial, viral and fungal infection still occurs, raising the question of whether these sterilization techniques are actually effective in accomplishing their purpose. This study, therefore, sought to determine the efficacy of one of the most employed sterilization techniques, that is, UV sterilization, by sampling six barbershops within Juja town. The study involved a cross-sectional design whereby barbershops with the UV sterilization chambers were sampled. Sampling involving wet-swabbing the tips of the electric shavers before and after UV sterilization for each barbershop. The samples were then taken to the laboratory to be analyzed to meet the objectives of the study.
Bioactive Producing Bacteria Obtained from Termite’s Subterranean Nests and Surrounding Mound Soil at University of Embu Farm
(University of Embu, 2019) Oduor, Harrison Otieno
Embu County has a range of climates ranging from wet and cool in the northern portions that traverse up Mount Kenya to relatively warm and dry in the central and southern parts of the County. Due to this gradient in climate University of Embu farm located in Embu County is densely forested with diverse plant on which termites degrade these dead plant litter. This facilitates carbon and nitrogen mineralization, nutrient availability and stimulation of microbial activity. An opportunity to obtain novel bioactive compounds has been linked to the discovery of bacteria from diverse and unexplored resources such as termites’ nests from different geographical areas. Herein we assessed antimicrobial and exoenzyme producing bacteria from termite’s subterranean nest and surrounding mound at University of Embu farm. This was achieved through collection of termite’ s subterranean nest and surrounding mound samples, isolation of bacterial colonies on various media supplemented with antifungal-cyclohexamide followed by morphological characterization of the isolates, and screening for exoenzyme and antimicrobial activities. A total of 25 isolates were obtained, 12 isolates and 13 isolates from subterranean nest and mound soil respectively. The isolates obtained produced various enzymes such as amylases, lipases, proteases, chitinase and cellulases. Cellulolytic bacteria associated with termites’ nest include Bacillus, Cellulomonas, and Micrococcus among others. Most of the isolates showed antagonistic activity against the test organisms such as E.coli, Pseudomonas, Salmonella, Shigella, B.subtilis, C.albicans and S.aureus and likely were presented by genera Nocardia and Actinobacteria which have been shown to produce bioactive. These results confirmed that termite’ s nest materials harbor bacteria that can produce bioactive compounds of significant in medical and industrial sectors.
Cellulolytic Bacteria in Rumen Contents of Carcasses from Majimbo Abattoir in Embu County Kenya
(University of Embu, 2019) Kenson, Fausto M.
Cellulose is a biopolymer that is found widely distributed on earth and it is a constituent of the plant cell walls and some algae. Cellulose hydrolyzing bacteria are adapted well to the environments containing cellulose biomass. The rumen of the ruminants can serve as an ideal source of cellulolytic bacteria since they help in the digestion of the cellulose in their feeds. Other cellulolytic microorganisms are the protozoa and fungi but bacteria constitutes the majority in the rumen. These bacteria that are able to degrade cellulose, can be utilized or rather applied in the clothing and fiber industry for the partial or complete synthesis of clothing and fiber materials. They can also be used in the environmental cleanup of the environments polluted with cellulose biomass. The main aim of the study was to explore the rumen content for the presence of the cellulolytic bacteria. The screening was able to determine the diversity of the cellulolytic bacteria in the rumen contents of the cattle in Majimbo abattoir and also helped determine the diversity of the substrates that these bacteria were able to utilize as sole carbon sources. Enumeration of these cellulolytic bacteria entailed spread plating in cellulose agar. The colonies grew differently were seperated and cultured in fresh cellulose media. The streaked plates were cultured until pure cultures were obtained. The isolates were screened for utilization of selected sole carbon sources. Those negative for cellulolytic activity test were considered non-cellulose hydrolyzing. The morphological was done on the isolates to determine their characteristics. This research generated bacterial isolates that can be utilized for degradation of cellulosic biomass. In addition, the isolates would act as bioresource for future studies. There were thirty isolates from the four samples. Three of the isolates (A308, D316 and C328) were Gram negative with the other twenty isolates being Gram positive. The morphological features showed that there were rods and cocci with only two isolates (B301 and A321) being rods and the rest being cocci. After screening the isolates for the utilization of various selected substrates they showed to be able to utilize a number of them but at varying extents. The cellulolytic bacteria are the ones that were able to utilize cellulose and CMC as sole source of carbon. CMC is made up of cellulose molecules and it is more complex in terms of the structure as compared to cellulose.
Changes in the physico-chemical parameters of the university dams
(University of Embu, 2019) Orina, Joan
Located in Embu County, at the southern side of Mount Kenya, there are four water reservoirs in the University all of which are connected to each other in a series. These dams have received little scientific attention to describe the changes in the physico-chemical properties as a result of increased human activities. This study examined variation of physico-chemical propertieswithin a period of three months from November 2018 to February 2019 on a weekly basis that covered both the wet and dry period.Conductivity meanvalues ranged from 137.03 to 177.23 µS/cm during different sampling dates and ranged from 155.3 to 179.8 µS/cm in different dams.Temperature mean values ranged from 24.3 ºC to 27.5 ºC during different sampling dates and ranged from 24.4 ºC to 27.2 ºC in different dams. PH mean values ranged from 6.9 to 9.3 during different sampling dates and ranged from 7.6 to 8.2 in different dams. Secchi depth mean values ranged from 20.3 cm to 33.3 cm during different sampling dates and ranged from 19.9 cm to 36.2 cm in different dams. Salinity mean values ranged from 0.06 ppt to 0.08 ppt during different sampling dates and ranged from 0.07 ppt to 0.08 ppt in different dams. TDS mean values ranged from 14.04 mg/L to 18.83 mg/L during different sampling dates and ranged from 15.7 mg/L to 22.8 mg/L in different dams. Chlorophyll-a mean values ranged from 3.01 mg/L to 3.70 mg/L during different sampling dates and ranged from 3.00 mg/L to 3.70 mg/L in different dams. Physico-chemical properties and aquatic community structure strongly influence the quality of water and therefore its importance as a resource to the people living around the reservoirs.
Characterization of Carica Papaya Seedlings Pathogens In Kamiu Tree Nurseries at Embu County
(University of Embu, 2021-09) Wangui, Nyoike Jackline
Papaya (Carica papaya L.) is an important fruit crop cultivated in many parts of the world. Its cultivation happens in different stages; from seeds, to seedling and finally to a grown papaya crop. Papaya crop in its seedling stage is highly infested by fungus and also bacterial diseases, mostly on leaves, causing the seedling to dry up and die. This causes huge economic losses to farmers cultivating papaya crop seedlings in tree nurseries for sale and also commercial losses since the papaya fruits have commercial benefits. The aim of the study was to characterize Carica papaya tree seedlings pathogens in Kamiu tree nurseries. Infected leaf samples were collected from papaya trees for pathogen isolation and characterization using morphological and molecular techniques. The results reported bacteria obtained from the isolates S1 ISOL1- S3 ISOL2 was confirmed as Erwinia spp. The isolated fungi were confirmed S ISOL1 as Penicillium spp, S ISOL2 as Corynespora spp and S ISOL3 as Phytophthora spp
Comparative Load of Escherichia coli in DAM3 AND DAM5 Of the University of Embu
(University of Embu, 2019) Njagi, Florida Wanjiku
Escherichia coli (E.coli) hardiness, versatility, broad use and ease of handling have made it the most intensively studied and best understood organism worldwide. However, research on E.coli has primarily examined it as a model organism, one that is abstracted from any natural history. It is a highly diverse organism with a complex, multi-faceted niche in the wild. Recent studies of ‘wild’ E.coli has, for example, revealed a great deal about its presence in the environment, its diversity and genomic evolution, as well as its role in the human micro biome and disease. E.coli is the best indicator of bacteriological quality of water. This, coupled with availability of affordable, fast, sensitive, specific and easier to perform detection methods, makes water analysis simple. University of Embu dams are surrounded by various agricultural practices and human habitats. Such occurrences could lead to contamination of surrounding waters through surface run offs. This experiment intends to determine the comparative load of E. coli between dams 3 and 5 of the University of Embu. Water was collected and tested using the Most Probable Number (MPN). MPN is a method used to estimate the concentration of viable microorganisms in a sample by serial dilution. It is commonly used in estimating microbial populations in soils, water and agricultural products. MPN is most commonly applied for quality testing of water i.e. to ensure whether the water is safe or not in terms of bacteria present in it. A group of bacteria commonly referred as fecal coliforms act as an indicator for fecal contamination of water. The presence of very few fecal coliform bacteria would indicate that water probably contains no disease-causing organisms, while the presence of large numbers of fecal coliforms would indicate a very high probability that the water could contain disease-producing organisms making the water unsafe for consumption. Water being tested was diluted serially and inoculated in MacConkey agar which is both a selective and differential media. It contains bile salts and the dye crystal violet, which inhibit the growth of gram-positive bacteria and select for gram-negative bacteria. It also contains the carbohydrate lactose, which allows differentiation of gram-negative bacteria based on their ability to ferment lactose. Organisms which ferment lactose produce acid end product which reacts with the pH indicator neutral red, and produce a pink color. Both dams have high number of E.coli loads though the greatest number was observed in dam 3.E.coli grows in a number of substrates like skimmed milk ,xylose and cellulose and stains negative during gram staining due to the presence of peptidoglycan in their cell wall. Regular water quality analysis should be done and agricultural activities within water bodies avoided to reduce microbial runoffs and contamination of water bodies.
Determination of effect of water availability (during the dry season) on abudance of vachellia xanthophloea around dam 5 in Embu University, Embu county, Kenya
(University of Embu, 2019) Nga’ng’a, Mary Wanjiku
Water sources are an important feature in many terrestrial ecosystems as they provide continuity of the hydrological cycle in many aspects. They provide vapor that rises to form clouds and later fall as rain precipitation also, they store water that evaporates to form the vapor. Many living organisms, including plants are dependent on water for their development. The higher the primary productivity the higher the diversity as hypothesized in ecological laws. This explains why tropical ecosystems have more species diversity than desert ecosystems. Far from that, abundance of trees is partly determined by water availability in an area. Soil is from where plants derive the water that they utilize to perform various functions. Therefore, it is only right to consider soil water as a parameter to consider when checking whether water availability affects plant abundance. The only way that can determine the age of trees is dbh. It is used to show the developmental stages for tree species. Narrowing down the population to a particular age group of a tree species and ruling out the probability of difference in soil moisture will help determine whether distance from a water source determines abundance. Because older trees are nearer the water table level and younger tree abundance maybe determined by dispersal, theirabundance may be measured separately. Assuming that the climatic conditions and that their response is at the same level because they samples are from the same geographical area. This will help show importance and high value that water sources should be given or levelled at.

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