The crystal structure of the Hazara virus nucleocapsid protein

Background: Hazara virus (HAZV) is a member of the Bunyaviridae family of segmented negative stranded RNA viruses, and shares the same serogroup as Crimean-Congo haemorrhagic fever virus (CCHFV). CCHFV is responsible for fatal human disease with a mortality rate approaching 30 %, which has an increased recent incidence within southern Europe. There are no preventative or therapeutic treatments for CCHFV-mediated disease, and thus CCHFV is classified as a hazard group 4 pathogen. In contrast HAZV is not associated with serious human disease, although infection of interferon receptor knockout mice with either CCHFV or HAZV results in similar disease progression. To characterise further similarities between HAZV and CCHFV, and support the use of HAZV as a model for CCHFV infection, we investigated the structure of the HAZV nucleocapsid protein (N) and compared it to CCHFV N. N performs an essential role in the viral life cycle by encapsidating the viral RNA genome, and thus, N represents a potential therapeutic target. Results: We present the purification, crystallisation and crystal structure of HAZV N at 2.7 Å resolution. HAZV N was expressed as an N-terminal glutathione S-transferase (GST) fusion protein then purified using glutathione affinity chromatography followed by ion-exchange chromatography. HAZV N crystallised in the P212121 space group with unit cell parameters a = 64.99, b = 76.10, and c = 449.28 Å. HAZV N consists of a globular domain formed mostly of alpha helices derived from both the N- and C-termini, and an arm domain comprising two long alpha helices. HAZV N has a similar overall structure to CCHFV N, with their globular domains superposing with an RMSD = 0.70 Å, over 368 alpha carbons that share 59 % sequence identity. Four HAZV N monomers crystallised in the asymmetric unit, and their head-to-tail assembly reveals a potential interaction site between monomers. Conclusions: The crystal structure of HAZV N reveals a close similarity to CCHFV N, supporting the use of HAZV as a model for CCHFV. Structural similarity between the N proteins should facilitate study of the CCHFV and HAZV replication cycles without the necessity of working under containment level 4 (CL-4) conditions

Macro and Trace Element Accumulation in Edible Crabs and Frogs in Alaro Stream Ecosystem, Ibadan

The tissue accumulation of five macroelements (Na, Mg, K, Ca, Fe) and twelve trace elements (Vd, Mn, Co, Ni, Cu, Zn, As, Se, Mo, Ag, Cd, Pb) were assessed in the organs of the edible frogs; Xenopus laevis and Rana esculentus, and whole body of the crab, Callinestes caught from Alaro Stream Floodplain (Ibadan, Nigeria).The liver of the edible frogs showed higher concentrations of Cu, Mo, and Cd, while Na, Mg, K, V, Mn, Fe, Co, Zn and Pb were higher than the other organs in Rana esculentus. In the liver of Xenopus laevis, Se and Ag were higher than the bone, gut, heart and muscle while Ag was the only trace element with the lowest concentration in the bones of the edible frog in contrast to Ca which ranked highest in the study. Ag was the least accumulated in the whole body of the crab, Callinestes while Ca was the highest mean level of 139364ppm in the study. Significant correlation was recorded between the bioaccumulated macro and trace elements in the crabs and frogs. With the exception of Ag, all the other trace elements exceeded the guidelines and standards given by the Federal Environmental Protection Agency of Nigeria. Public health consciousness and regular monitoring is therefore necessary in the consumption of these aquatic food resources. Macro and trace element accumulation in edible frogs and crabs in a contaminated watershed in the tropical region.Keywords: macro element, trace element, edible frogs, crab

Molluscicidal Effect Of Piper Guineense

The study was undertaken to assess the dosage-mortality ratio and toxic effects of Piper guineense fruit extracts on the adults of Biomphalaria pfeifferi , the snail intermediate host of Schistosoma mansoni , which causes intestinal schistosomiasis. The result showed significant toxic effects with crude ethanol and hot water fruits extracts. The estimated lethal dose concentration by arithmetic method (LC50 and LC90) using both crude ethanol and hot water fruit media extracts were found to be (0.10 ± 0.04, 0.9 ± 0.2) mgl-1 respectively for ethanolic extract and (5.0 ± 1.4, 8.5 ± 0.7) mgl-1 respectively for hot water extract. Ethanolic extract was more potent than hot water extract. An all or none phenomenon appeared characteristic of the biological activity of these extracts. There was significant decrease in oviposition rate (p < 0.02). The extract from the fruits of this tropical plant holds promise in the control of Biomphalaria pfeifferi

Molluscicidal Effect of Piper Guineense

The study was undertaken to assess the dosage-mortality ratio and toxic effects of Piper guineense fruit extracts on the adults of Biomphalaria pfeifferi, the snail intermediate host of Schistosoma mansoni, which causes intestinal schistosomiasis. The result showed significant toxic effects with crude ethanol and hot water fruits extracts. The estimated lethal dose concentration by arithmetic method (LC50 and LC90) using both crude ethanol and hot water fruit media extracts were found to be (0.10 ± 0.04, 0.9 ± 0.2) mgl−1 respectively for ethanolic extract and (5.0 ± 1.4, 8.5 ± 0.7) mgl−1 respectively for hot water extract. Ethanolic extract was more potent than hot water extract. An all or none phenomenon appeared characteristic of the biological activity of these extracts. There was significant decrease in oviposition rate (p < 0.02). The extract from the fruits of this tropical plant holds promise in the control of Biomphalaria pfeifferi

Occurrence and Deleterious Effects of Algal Blooms Associated With Some Pollutants in Three Man-Made Lakes

Associations of plankton genera, some of which are known to be potentially harmful and indicative of pollution stress in surface waters were studied alongside some of their corresponding physico-chemical parameters, in three man-made lakes (reservoirs) over a period of 18 months in Ibadan, Nigeria. These lakes receive sewage effluents and agricultural run-offs. Two of these, Lakes Awba and Main are sites of drinking water abstraction. Bloom-forming algal families found in association included members of the phytoplankton class Chlorophyceae: (Pediastrium spp and Spirogyra spp.), the Bacillariophyceae which included Synedra, Melosira and Nitzschia species and potentially toxin-producing genera of the class Cyanophyceae (Microcystis, Anabaena, Aphanizomenon and Lyngbya). The plankton exhibited significant correlations with pH, temperature, total suspended solids, dissolved oxygen, carbon dioxide, nitrate-nitrogen and ammonium-nitrogen at various seasons of the year. An altered physico-chemistry of large areas of the lake and a total absence of aquatic life in some highly polluted parts were recorded in the study. Reports from lake users were recorded, of contaminated bad tasting water unfit to drink, unpalatable fish and skin infections, all indicators of the far-reaching effects algae can have on fresh water supplies. This paper calls for more frequent and thorough monitoring of such resources Keywords: Sewage, Bloom–forming algae, pollution, water quality parameters, agricultural run-offs, eutrophic, harmful algal bloomsTropical Freshwater Biology Vol. 17 (1) 2008: pp. 53-7

Metal Distribution and Bioaccumulation in Water and Fish of a Tropical Lake

A study was conducted to investigate the metal (copper, zinc and manganese) concentrations in the surface water and fish of a man-made lake receiving agricultural and domestic effluents in Ibadan, Nigeria. The lake (Main Lake, IITA) is a site of drinking water abstraction and the major water source for the surrounding agricultural research farms. Factor analysis indicated that copper was an important contributor to the total variance observed in the lake, being involved in Factor 1 of the 6-factor model. Significant differences occurred in the copper and manganese levels of the organs of Oreochromis niloticus at P< 0.05 and P< 0.01 respectively and in manganese levels of Sarotherodon. galilaeus at P< 0.05. Significant differences did not occur in Lates niloticus and Synodontis nigrita organs. Bioaccumulation factors from water to fish muscles were highest for manganese ranging from 4.56-10.56; zinc from 1.83-5.67 and copper from 1-1.8. These factors showed that despite the low levels of these metals in surface water, there may be an onset of bioaccumulation in some of the fishes. This work contributes to the baseline data on the presence and effects of metals in African freshwaters and could aid future plans for the control of toxic build-up in our aquatic environments. Keywords: Metal, concentrations, lake, bioaccumulation, water, fish and IITATropical Freshwater Biology Vol. 17 (1) 2008: pp. 81-9