Biological Sciences

Methane gas (CH 4 ) has been identified as an important alternative source of carbon and energy in some freshwater food
webs. CH 4 is oxidized by methane oxidizing bacteria (MOB), and subsequently utilized by chironomid larvae, which may
exhibit low d 13 C values. This has been shown for chironomid larvae collected from lakes, streams and backwater pools.
However, the relationship between CH 4 concentrations and d 13 C values of chironomid larvae for in-stream impoundments is
unknown. CH 4 concentrations were measured in eleven in-stream impoundments located in the Queich River catchment
area, South-western Germany. Furthermore, the d 13 C values of two subfamilies of chironomid larvae (i.e. Chironomini and
Tanypodinae) were determined and correlated with CH 4 concentrations. Chironomini larvae had lower mean d 13 C values (2
29.2 to 225.5 %), than Tanypodinae larvae (226.9 to 225.3 %). No significant relationships were established between CH 4
concentrations and d 13 C values of chironomids (p.0.05). Mean d 13 C values of chironomid larvae (mean: 226.8%, range: 2
29.2% to 225.3%) were similar to those of sedimentary organic matter (SOM) (mean: 228.4%, range: 229.3% to 227.1%)
and tree leaf litter (mean: 229.8 %, range: 230.5% to 229.1%). We suggest that CH 4 concentration has limited influence
on the benthic food web in stream impoundments.

The study was conducted at two sites in Sondu-Miriu basin between November 2010 and May 2011, using runoff plots to determine the temporal variation of sediments, organic matter, solids and surface runoff from agricultural land uses. At Kabianga, lower sediment and surface runoff values were observed in natural vegetation while runoff was generally higher in April-May 2011 wet season. While there were significantly lower sediment concentrations and higher runoff volumes, organic content was significantly lower in April-May 2011. Principal Components Analysis correlated surface runoff and erosion to seasonal land use activities particularly during wet seasons depicting the influence of hydrology on surface runoff pollution. In Sondu, sediment concentrations were lower in natural vegetation. Surface runoff was higher in January-March 2011 in natural vegetation but lowest in cropped systems during April-May, 2011. Solids and organic matter were significantly higher in November-December 2011 (p<0.05). PCA linked surface runoff quality to changes in hydrological periods which influenced the nature, quality and quantity of material transported via surface runoff. PCA for River Sondu-Miriu at Kabianga suggested ionic pollution by dissolved substances (r = 0.77-0.99, p<0.01) and sediment load introduced via surface runoff during wet seasons. In Sondu, PCA associated ionic pollutants and sediment loads to hydrological changes relating to seasonality (r = -0.75-0.99, p<0.01). Temporal variations in surface runoff volumes, water quality and sediment load correlated significantly to hydroperiods in Sondu-Miriu basin. Hydrological changes impacted highly in agricultural land uses with reduced land cover which increased surface runoff accompanied by higher sediment loads.

A study of macroinvertebrate distribution in relation to different levels of human and animal physical disturbance
of the sediments of the Njoro (highly disturbed) and Ellegirini (less disturbed) rivers was conducted from October 2001 to June 2002, and again in 2012 only in the Njoro River. The rivers have similar climate and land-use characteristics but differ in the frequency and intensity of human and animal disturbance of their sediment surfaces. Benthic macroinvertebrates were sampled during both low discharge, when the disturbances were high, and high discharge, when the disturbances were low. Macroinvertebrate abundance and diversity were higher in the Ellegirini than in the Njoro River. Sites characterised by high disturbance had low macroinvertebrate abundance and diversity, and were dominated by one taxon that tolerated disturbance irrespective of flow regimes. A consistent decline in macroinvertebrate abundance and diversity in the Njoro River as a result of increased disturbance was evident in 2001–2002 and 2012. Macroinvertebrates are most probably redistributed via migration and dispersal, due to these physical disturbances.

Riparian communities in river catchments worldwide face challenges in sustainable utilisation of available natural resources, including surface and ground water.This study examined the spatio-temporal variability in water quality footprint in the upper Njoro River Catchment (NRC), Kenya, linking source-and-consumption to domestic water quality trends in surface and groundwater during the wet-2014 and dry-2017 seasons. In 2014, pH ranged from 6.4-9.0; mean conductivity was 141 µS cm-1 while oxygen and temperature averaged at 6.3 mg L-1 and 19.1 °C respectively. Nitrate-N levels ranged from 0-10.6 mg L-1 and total phosphorus (TP) was highest at 0.68 mg L-1. However, in 2017, Nitrate-N peaked at 8.1 mg L-1 while TP decreased to 0.4 mg L-1. There was significant zonal variability of water pH, conductivity, oxygen, Nitrate-N, SRP and TP. Microbial densities in household water ranged between 0-2 Escherichia coli (EC)and 2-16 Total Coliform (TC) log-cfu/100 ml water in 2014. In 2017, the respective microbial loads doubled. There was a significant seasonal variability in EC and TC densities which also differed significantly between mid-and upstream in 2017 (p<0.001). The overall water quality significantly varied spatio-temporally highlighting critical aspects when designing measures to enhance domestic water safety particularly at household level, with zoning as an important criterion, in river catchments.

Copper (Cu) and Cobalt (Co) are among the most toxic heavy metals from mining and other industrial activities. Both are known to pose serious environmental concerns, particularly to water resources, if not properly treated. In recent years several filamentous fungal strains have been isolated, identified and assessed for their heavy metal biosorption capacity for potential application in bioremediation of Cu and Co wastes. Despite the growing interest in heavy metal removal by filamentous fungi, their exploitation faces numerous challenges such as finding suitable candidates for biosorption. Based on current findings, various strains of filamentous fungi have high metal uptake capacity, particularly for Cu and Co. Several works indicate that Trichoderma, Penicillium, and Aspergillus species have higher Cu and Co biosorption capacity compared to other fungal species such as Geotrichum, Monilia, and Fusarium. It is believed that far more fungal species with even higher biosorption cap...

Africa accounts for nearly 30% of the discovered world’s mineral reserves, with half of the world’s platinum group metals deposits, 36% of gold, and 20% of cobalt being in Southern Africa (SA). The intensification of heavy-metal production in the SA region has exacerbated negative human and environmental health impacts. In recent years, mining waste generated from industrial and artisanal mining has significantly affected the ecological integrity of SA aquatic ecosystems due to the accelerated introduction and deposition of heavy metals. However, the extent to which heavy-metal pollution associated with mining has impacted the aquatic ecosystems has not been adequately documented, particularly during bioassessments. This review explores the current aquatic ecological impacts on the heavily mined river basins of SA. It also discusses the approaches to assessing the ecological risks, inherent challenges, and potential for developing an integrated ecological risk assessment protocol fo...

A Water Quality Index (WQI) is a tool that describes the overall water quality by combining complex and technical water quality information into a single meaningful unitless numerical value. WQIs predict water quality since they reflect the impact of multiple Water Quality Parameters (WQPs) and allow for spatial-temporal comparison of water quality status. Most African countries employ adapted WQIs by modifying the original index (or indices) and propose their concepts for evaluating the quality of surface and groundwater, which is normally accompanied by irregularities. The current review examined the process(es) involved in WQI modifications for monitoring water quality in Africa, explored associated limitations, and suggested areas for improvement. A review of 42 research articles from five databases in the last ten years (2012–2022) was conducted. The findings indicated Weighted Arithmetic (WAWQI) and the Canadian Council of Ministers of Environment (CCMEWQI) as the most adapted...

The increasing use of complementary and alternative medicine (CAM) has kindled the need for scientific evaluation of the mechanism of action of CAMs. Although, licorice, a common ingredient in many Traditional Chinese medicine (TCM) has attracted great attention for its antitumor and immunomodulatory activities, the mechanism of action of its polysaccharides is still unclear. Here we report the immunomodulatory activity of licorice polysaccharides in vivo. The differential anticancer activities of licorice polysaccharides by tumorigenesis and immunomodulation was evaluated in vivo. Six weeks old, 120 CT-26 tumor bearing BALB/c mice, weighing 20 ± 2 g were used. They were randomly divided into six groups, three groups receiving high molecular weight (fraction A), low molecular weight (fraction B) polysaccharides and crude extract (fraction C); positive, negative and normal groups receiving cytoxin, saline and normal diet respectively. Weight of mice and tumors was determined and tumo...

Herbal medicines have traditionally played a major role in the management of diabetes in Asian countries for centuries. Panax notoginseng (Burk) F. H. Chen (Araliaceae) known as Tiánqī or san qi is a well-known medicinal herb in Asia for its long history of use in Chinese medicine. Qualified as 'the miracle root for the preservation of life', it has been used in China for 600 years, for treatment of various diseases. Panax notoginseng saponins (PNS) are the key active components. PNS have been widely used in China for treatment of cardiovascular diseases. However, scientific studies have shown a wide range of other pharmacological applications including anti-cancer, neuroprotective and anti-inflammatory agents, immunologic adjuvant and prevention of diabetes complications. Recently, hypoglycemic and anti-obesity properties of PNS have also been demonstrated. The present review highlights the effects of PNS on glucose production and absorption, and on inflammatory processes that seem to play an important role in the development of diabetes.

Withania somnifera, Warbugia ugandensis, Prunus africana and Plectrunthus barbatus are used traditionally in Kenya for treatment of microbial infections and cancer. Information on their use is available, but scientific data on their bioactivity, safety and mechanisms of action is still scanty. A study was conducted on the effect of organic extracts of these plants on both bacterial and fungal strains, and their mechanisms of action. Extracts were evaluated through the disc diffusion assay. Bacteria and yeast test strains were cultured on Mueller-Hinton agar and on Sabouraud dextrose agar for the filamentous fungi. A 0.5 McFarland standard suspension was prepared. Sterile paper discs 6 mm in diameter impregnated with 10 ml of the test extract (100 mg/ml) were aseptically placed onto the surface of the inoculated media. Chloramphenicol (30 mg) and fluconazole (25 mg) were used as standards. Discs impregnated with dissolution medium were used as controls. Activity of the extracts was expressed according to zone of inhibition diameter. MIC was determined at 0.78-100 mg/ml. Safety studies were carried using Cell Counting Kit 8 cell proliferation assay protocol. To evaluate extracts mechanisms of action, IEC-6 cells and RT-PCR technique was employed in vitro to evaluate Interleukin 7 cytokine. Investigated plants extracts have both bactericidal and fungicidal activity. W. ugandensis is cytotoxic at IC 50 ,50 mg/ml with MIC values of less than 0.78 mg/ml. Prunus africana shuts down expression of IL 7 mRNA at 50 mg/ml. W. somnifera has the best antimicrobial (1.5625 mg/ml), immunopotentiation (2 times IL 7 mRNA expression) and safety level (IC 50 .200 mg/ml). Fractions from W. ugandensis and W. somnifera too demonstrated antimicrobial activity. Mechanisms of action can largely be attributed to cytotoxicity, Gene silencing and immunopotentiation. Use of medicinal plants in traditional medicine has been justified and possible mechanisms of action demonstrated. Studies to isolate and characterize the bioactive constituents continue.

Background: Chinese licorice, (Glycyrrhiza uralensis Fisch.) is one of the commonly prescribed herbs in Traditional Chinese Medicine (TCM). Gancao, as commonly known in China, is associated with immune-modulating and anti-tumor potential though the mechanism of action is not well known. In this study, we investigated the in vitro immunomodulatory and antitumor potential of Glycyrrhiza uralensis polysaccharides fractions of high molecular weight (fraction A), low molecular weight (fraction B) and crude extract (fraction C). Methods: Cell proliferation and cytotoxicity was investigated using Cell Counting kit 8 (CCK-8) on Intestinal epithelial cell line (IEC-6) and Colon carcinoma cell line (CT-26). IL-7 gene expression relative to GAPDH was analysed using Real time PCR. The stimulation and viability of T lymphocytes was determined by Trypan blue exclusion assay. Results: G.uralensis polysaccharides did not inhibit proliferation of IEC-6 cells even at high concentration. The ED 50 was found to be 100 μg/ml. On the other hand, the polysaccharides inhibited the proliferation of cancer cells (CT-26) at a concentration of ≤50 μg/ml. Within 72 h of treatment with the polysaccharides, expression of IL-7 gene was up-regulated over 2 times. It was also noted that, IEC-6 cells secrete IL-7 cytokine into media when treated with G.uralensis polysaccharides. The secreted IL-7 stimulated proliferation of freshly isolated T lymphocytes within 6 h. The effect of the polysaccharides were found to be molecular weight depended, with low molecular weight having a profound effect compared to high molecular weight and total crude extract. Conclusion: Our findings indicate that G.uralensis polysaccharides especially those of low molecular weight have a potential as anticancer agents. Of great importance, is the ability of the polysaccharides to up-regulate anticancer cytokine IL-7, which is important in proliferation and maturation of immune cells and it is associated with better prognosis in cancer. Therefore, immunomodulation is a possible mode of action of the polysaccharides in cancer therapy.

BACKGROUND Cardiovascular disease (CVD), which encompasses a spectrum of diseases including hypertension, is perennial among the leading causes of morbidity and mortality worldwide. [1-6] Many CVDs are pathophysiologically associated with deficiency of nitric oxide (NO) in the heart and blood vessels. [7] The regulation of vascular tone is one among therapeutic interventions used for the appropriate control of blood pressure as contraction and dilation of blood vessels directly control blood pressure.

Since time immemorial, plants and their compounds have been used in the treatment and management of various ailments. Currently, most of conventional drugs used for treatment of diseases are either directly or indirectly obtained from plant sources. The fungal group of plants is of significance, which not only provides food directly to man but also has been source of important drugs. For instance, commonly used antibiotics are derived from fungi. Fungi have also been utilized in the food industry, baking, and alcohol production. Apart from the economic importance of the microfungi, macrofungi have been utilized directly as food, which is usually got from their fruiting bodies, commonly known as mushrooms. Due to their richness in proteins, minerals, and other nutrients, mushrooms have also been associated with boosting the immune system. This makes mushrooms an important food source, especially for vegetarians and immunosuppressed individuals including the HIV/AIDS persons. In compl...

Ethnopharmacological relevance: Fungi have been used in traditional systems both as food and medicine. In China the mushrooms are widely used in Traditional Chinese Medicine (TCM). On one hand residue resulting from medicinal plants are treated as waste, yet the environment in which medicinal plants including fungi grow greatly influences the potency and quantities of bioactive secondary metabolites thereof. Since Mushrooms are widely consumed for immunomodulatory purposes especially for people suffering from tumors, this study sought to find out whether there is enhanced effect of mushroom polysaccharides extracts of Trametes robiniophila murr a Chinese fungus, grown on media supplemented with Chinese herbal drug residues both in vitro and in vivo as an immunotherapeutic remedy for cancer. Methodology: We used Intestinal Epithelial Cells (IEC) known to produce IL-7 cytokine which works on the immune system and on the postulation that polysaccharide extracts work by up regulating IL-7. The polysaccharide extracts investigated were obtained from mushrooms grown on media supplemented with Chinese herbal residues. The Cell Counting Kit-8 (CCK-8) proliferation assay procedure was used to asses' cell proliferation. Extract concentrations ranging from 0.00001-100µg/ml was used in the cell proliferation assay. IEC-6 cells grown in media supplemented with 100µg/ml mushroom polysaccharides extracts was used in vitro and RT-PCR technique employed to evaluate up-regulation of IL-7 in a time dependent manner ranging from 3 to 72 hours. The extract with best IL-7 expression was selected for further evaluation in vivo at 30mg/mice/day in mice infected with CT-26 colon cancer tumor cells. Cyclophosphamide at 20mg/mice/day was taken as the positive control drug. Flow cytometry was employed to evaluate the peripheral blood CD4 + and CD8 + lymphocytes. The extract was further tested in vitro on CT-26 cells (100 & 200 µg/ml), to explore direct inhibition. Results: 1µg/ml was found to give optimum IEC-6 cell growth however; 100µg/ml was determined as the ED 50 and used as the minimum evaluation concentration for IL-7 expression. The polysaccharide extracts obtained from mushrooms supplemented with the Chinese herb Gancao (Glycyrrhiza glabra L. var. glandulifera) residues were found to up-regulate IL-7 best. 6 hours exposure of cells to extract gave optimal IL7 expression of over 1.2 times at 100µg/ml compared to polysaccharide extracts from mushrooms grown on normal media. Extracts obtained at temperatures ranging between 70-90 o C were found to be most ideal. The extract was found to increase the CD4 + and CD8 + lymphocytes in vivo in mice a reflection on IL-7 up regulation in the intestinal mucosa and further to inhibit CT-26 cell growth in a significant way at P≤0.05. Conclusion: Polysaccharide extracts obtained from mushroom Trametes robiniophila murr grown on media supplemented with Chinese herb Gancao (G. glabra L. var. glandulifera) residues offers increased immunomodulatory effect as an alternative treatment to cancer cases. It can be employed as a prescription supplement for immunotherapy and immuno surveillance. The mechanism of action is probably stimulation of IEC-6 cells to produce increased IL-7 Cytokine responsible for resultant adaptive immunity and cancer immuno surveillance. The polysaccharide extract too has chemotherapeutic effect and is safe.