Annual Research & Review in Biology

The bovine leukaemia virus (BLV) is widely spread all over the world. Currently, treatment of leukaemia-infected animals is not carried out. Not all virus carriers become ill with leukaemia. The existing genetic resistance to the disease is due to the presence of alleles of resistance of the main histocompatibility complex. However, another mechanism of resistance is possible, which is associated with the penetration of the virus into the cell. The work aimed to analyse the currently available data on possible receptors of the virus. Four potential molecules were found. The results suggest that the potential BLV receptor is a CD209 protein.

To reduce negative effects of drought on plants, the use of plant growth- promoting rhizobacteria (PGPR) is an effective way to investigate that. The aim of the present study was to assess the bacterial characteristics Bacillus subtilis, Bacillus cereus, Pseudomonas koreensis, Pseudomonas fluroscence, and Enterobacter cloacae as growth, IAA production, phosphate solubilization, seed germination under different concentrations of polyethylene glycol (PEG 6000), and their efficacy of single or dual inoculation with two superior strains in lyzimeter experiment for improving growth and yield of sensitive variety of wheat (Triticum aestivum L.) cv. Sids 1 under different stress irrigation water 100, 70 and 35% of field capacity. Among the tested strains only 2 strains B. subtilis and P. koreensis showed a stable growth even in the maximum 40% PEG concentration. Also, P. koreensis produced the highest amount of IAA (1.84 µg ml^-1), and solubilise maximum amount of P (1.59 µg ml^-1), and improved seed germination at 30% PEG concentration. On the other hand, in gnotobiotic sand system experiment, PGPR increase growth dynamics as well as proline content and root colonisation of wheat plants over uninoculated control under drought-stressed conditions.

In lyzimeter experiment, single and dual inoculation treatments showed a significant increase of physiological and biochemical parameters of the plant under different drought stress treatments. Also, maximum increase 29.08 % in ascorbate peroxidase and 27.38% in catalase activities due to dual inoculation treatments T₁₂ (Inoculation with B. subtilis + P. koreensis and irrigated at field capacity 35%), with respect to the corresponding unstressed control T₁₀ (Inoculation with B. subtilis + P. koreensis and irrigated at field capacity 100%). Also, significant increase in grain yield, straw yield, biological yield and harvest index were observed under different drought stress. These results may be related to increase uptake of water and nutrients in wheat plant and reflected in better plant growth and yield.

Aims: To investigate the variation in the activities of some soil enzymes and microbial respiration during phytoremediation of crude oil polluted agricultural soil.

Study Design:  Indigenous plants of a crude oil polluted agricultural farmland were harvested and identified. Two species (Schwenkia americana L. and Spermacoce ocymoides Burm. f.) were selected for this study. Nursery was set up using sterile soil and mature and viable seeds of selected species, and germinated seedlings were transplanted into an 8 kg potted homogenised polluted soil for remediation.

Place and Duration of Study: Polluted agricultural soil from Ogoniland Nigeria, University of Port Harcourt ecological garden, between May 2017 and February 2018.

Methodology: Protease activity was determined based on the amino acids released after incubation of soil with sodium caseinate. Phosphatase activities determination was based on determining the degradation extent of ρ-nitrophenol phosphate (PNPP) by the samples. Dehydrogenase activity was determined based on estimation of 2,3,5- triphenyltetrazolium chloride (TTC) reduction to triphenyl formazan (TPF)  in soils after incubation. The substrate induced method was adapted to estimate the respiratory activity. Organic matter was determined by weight loss on ignition method.

Results: Dehydrogenase activities in remediated groups increased after 4 weeks but decreased at the end of the remediation period. Protease and phosphatase activities, and soil organic matter of remediated groups reduced over time while the soil microbial respiratory activity reduced at the end of 12 weeks remediation. There was a restoration of the polluted soils by the treatments towards normalcy with regards to activities of proteases, acid and alkaline phosphatases, and dehydrogenases.

Conclusion: Soil microbial activities can reflect soil quality, and soil enzyme activities can directly reflect the metabolic need and nutrient availability of soil microorganisms. The extracellular enzymes (protease, dehydrogenase, acid and alkaline phosphatase) were shown to vary with crude oil pollution relative to time thus indicating ameliorative effects.

Rhizoprionodon acutus (Rüppell) 1837, commonly known as ‘Milk shark’ is the frequently available elasmobranch from the Nellore (14.43°N 79.97°E.) coast off Bay of Bengal. A total of 152 R. acutus were collected from this coast during January, 2014- December, 2015, of which 89 hosts were infected with one or more parasites. A total of eleven species were collected, comprising of 6 cestodes, 2 nematodes, 1 Monogenean, 1 copepod and 1 isopod. Various ecological parameters such as prevalence, mean intensity, mean abundance and index of infection were calculated to determine the monthly population dynamics and the seasonal dynamics of the parasites in R. acutus. The study was carried out for both overall and groupwise parasitization. Endoparasitic infection predominated the ectoparasitic infection in the host. The study reveals the role of the temperature and season in the recruitment of parasite fauna in the hosts. The present study would be a great contribution to the knowledge of the metazoan parasite fauna of elasmobranch fishes to the future helminthologists from this Nellore Coast, Bay of Bengal.

Background: Vegetable consumption is a major source of vitamins, minerals and dietary fibre for the body. While fresh vegetables play a key role in the prevention of some chronic diseases, cancers, and alleviation of micronutrient deficiencies, some have been associated with foodborne parasitic infections.

Objectives: We investigated the parasitic contamination of fresh vegetables sold in three market places in the Cape Coast Metropolis in Ghana.

Materials and Methods: In this study conducted over a period of three (3) months, a total of one hundred and twenty-six (126) vegetable samples were obtained from three (3) selected markets in the Metropolis. Six (6) different species of vegetables namely tomato (Solanum lycopersicum), cabbage (Brassica oleracea var capitata), carrot (Daucus carota), lettuce (Lactuca sativa), spring onion (Allium fistulosum) and green pepper (Capsicum annuum) were subjected to parasitological examination for the detection of parasite forms such as larvae, ova and cysts.

Results: The overall prevalence of parasitic contamination of vegetables in this study was 52.4%. Five different parasites were detected namely Strongyloides spp, Hookworm, Trichuris trichiura, Ascaris lumbricoides and Entamoeba coli. The prevalence of parasitic contamination was higher in leafy vegetables such as spring onions (90.5%), lettuce (76.2%) and cabbage (66.7%). Multiple parasitic contaminations were a common feature of leafy vegetables than smoothly surfaced ones such as green pepper and tomatoes.

Conclusion: The study revealed that most vegetables purchased from the markets in the metropolis were highly contaminated with intestinal parasites. It is therefore recommended that vegetables should be subjected to thorough disinfection processes before being served for food to reduce the transmission of intestinal parasites.