Sperm competition in tropical versus temperate zone birds

Sperm competition represents an important component of post-copulatory sexual selection. It has been argued that the level of sperm competition declines in birds towards the equator. However, to date, sperm competition estimates have been available mainly for avian species inhabiting the northern temperate zone. Here we apply a novel approach, using the coefficient of between-male variation (CV_bm) in sperm size as an index for sperm competition risk, in a comparative analysis of 31 Afrotropical and 99 northern temperate zone passerine species. We found no difference in sperm competition risk between the two groups, nor any relationship with migration distance. However, a multivariate model indicated that sperm competition risk was highest in species with a combination of low body mass and few eggs per clutch. The effect of clutch size was most pronounced in tropical species, which indicates that sperm competition risk in tropical and temperate species is differently associated with particular life-history traits. Although tropical species had lower sperm competition risk than temperate zone species for overlapping clutch sizes, the idea of a generally reduced risk of sperm competition in tropical birds was not supported by our analysis.     

The evolutionary and molecular features of the broad-host-range plant pathogen Sclerotinia sclerotiorum

Sclerotinia sclerotiorum is a pathogenic fungus that infects hundreds of plant species, including many of the world's most important crops. Key features of S. sclerotiorum include its extraordinary host range, preference for dicotyledonous plants, relatively slow evolution, and production of protein effectors that are active in multiple host species. Plant resistance to this pathogen is highly complex, typically involving numerous polymorphisms with infinitesimally small effects, which makes resistance breeding a major challenge. Due to its economic significance, S. sclerotiorum has been subjected to a large amount of molecular and evolutionary research. In this updated pathogen profile, we review the evolutionary and molecular features of S. sclerotiorum and discuss avenues for future research into this important species.     

Effects of AQ4N and its reduction product on radiation-mediated DNA strand breakage

Supercoiled plasmid pBR322 DNA was irradiated in phosphate buffer by 60Co gamma-rays at a dose rate 19.26 Gy/min and total dose of 10 Gy in the presence of a bioreductive antitumour prodrug namely 1,4-bis [?2-(dimethylamino-N-oxide)ethyl? amino] 5, 8-dihydroxyanthracene-9,10-dione (AQ4N) and its DNA affinic reduction product 1,4-bis[?2(dimethylamino)ethyl? amino] 5,8-dihydroxyanthracene-9,10-dione (AQ4) under air and nitrogen. AQ4N and AQ4 were found to protect against radiation-induced plasmid single and double strand breakage as assessed by agarose gel electrophoresis. The differences between the two agents, and between atmospheres of air or nitrogen were negligible. It was also found that the protection efficiencies of the compounds were pH dependent and showed maximum protection at pH 6. These results indicate that protection of DNA by AQ4 and AQ4N against radiation damage is an indirect effect since both agents are equally effective despite major differences in their DNA affinity. It is likely that radiation-induced phosphate buffer radicals are intercepted by AQ4 and AQ4N in a pH-dependent process.     

Evaluation of various agro-wastes for traditional black soap production

The agricultural wastes, cocoa-pod husks, palm-bunch waste, sorghum chaff and groundnut shells, which are normally thrown away have been used in the production of black soap. Unlike other soaps which are made from oils and chemicals, black soap is made from oils and agro-wastes ashes. Chemical analysis indicated that the liquid extract from the ashes of the different agro-wastes used contained various amounts of potassium and sodium compounds. The most common ingredient in the agro-wastes was potassium carbonate. The amount of potassium carbonate was 56.73 +/- 0.16% in cocoa-pod ash, 43.15 +/- 0.13% in palm-bunch ash, 16.65 +/- 0.05% in groundnut shell ash and 12.40 +/- 0.08% in sorghum chaff ash. Soaps made from the agro-wastes ashes had excellent solubility, consistency, cleansing and lathering abilities.     

Downstream effects on human low density lipoprotein of homocysteine exported from endothelial cells in an in vitro system

A model system is presented using human umbilical vein endothelial cells (HUVECs) to investigate the role of homocysteine (Hcy) in atherosclerosis. HUVECs are shown to export Hcy at a rate determined by the flux through the methionine/Hcy pathway. Additional methionine increases intracellular methionine, decreases intracellular folate, and increases Hcy export, whereas additional folate inhibits export. An inverse relationship exists between intracellular folate and Hcy export. Hcy export may be regulated by intracellular S-adenosyl methionine rather than by Hcy. Human LDLs exposed to HUVECs exporting Hcy undergo time-related lipid oxidation, a process inhibited by the thiol trap dithionitrobenzoate. This is likely to be related to the generation of hydroxyl radicals, which we show are associated with Hcy export. Although Hcy is the major oxidant, cysteine also contributes, as shown by the effect of glutamate. Finally, the LDL oxidized in this system showed a time-dependent increase in uptake by human macrophages, implying an upregulation of the scavenger receptor. These results suggest that continuous export of Hcy from endothelial cells contributes to the generation of extracellular hydroxyl radicals, with associated oxidative modification of LDL and incorporation into macrophages, a key step in atherosclerosis. Factors that regulate intracellular Hcy metabolism modulate these effects.     

An improved semiautomated rapid method of extracting genomic DNA for molecular marker analysis in cocoa,<Emphasis Type="Italic">Theobroma cacao</Emphasis> L

DNA extraction is a time-consuming and expensive component of molecular marker analysis, constituting about 30–60% of the total time required for sample processing. Furthermore, the procedure for extracting high-quality DNA from tree species such as cocoa differs from extraction protocols suitable for other crop plants. This is accompanied by problems in collecting leaf tissues from field-grown cocoa trees, where storage facilities are not available and where transporting samples to laboratory for immediate refrigeration is usually impossible. We preserved cocoa leaf tissues in the field in an NaCl-CTAB-azide solution (as described in Rogstad, 1992), which did not require immediate refrigeration. This method also allowed preservation of leaf tissues for a few days during transportation and protected leaf tissues from bacterial and fungal attacks. Once transported to the laboratory, the samples were stored at 4°C for almost 1 y. To isolate good-quality DNA from stored leaf tissues, a rapid semiautomated and relatively high-throughput protocol was established. The procedure followed a modified CTAB/β-mercaptoethanol method of DNA extraction in a 96-well plate, and an automated system (i.e., GenoGrinder 2000) was used to grind the leaf tissues. The quality of DNA was not affected by long storage, and the quantity obtained per sample was adequate for about 1000 PCR reactions. Thus, this method allowed isolation of about 200 samples per day at a cost of $0.60 per sample and is a relatively high-throughput, low-cost extraction compared with conventional methods that use manual grinding and/or expensive kits.     

Matrix metalloproteinases are involved in C-terminal and interglobular domain processing of cartilage aggrecan in late stage cartilage degradation.

Monoclonal antibody (MAb) technology was used to examine aggrecan metabolites and the role of aggrecanases and matrix metalloproteinases (MMPs) in proteolysis of the interglobular domain (IGD) and C-terminus of aggrecan. An in vitro model of progressive cartilage degradation characterized by early proteoglycan loss and late stage collagen catabolism was evaluated in conjunction with a broad-spectrum inhibitor of MMPs. We have for the first time demonstrated that IGD cleavage by MMPs occurs during this late stage cartilage degeneration, both as a primary event in association with glycosaminoglycan (GAG) release from the tissue and secondarily in trimming of aggrecanase-generated G1 metabolites. Additionally, we have shown that MMPs were responsible for C-terminal catabolism of aggrecan and generation of chondroitin sulfate (CS) deficient aggrecan monomers and that this aggrecan truncation occurred prior to detectable IGD cleavage by MMPs. The onset of this later stage MMP activity was also evident by the generation of MMP-specific link protein catabolites in this model culture system. Recombinant MMP-1, -3 and -13 were all capable of C-terminally truncating aggrecan with at least two cleavage sites N-terminal to the CS attachment domains of aggrecan. Through analysis of aggrecan metabolites in pathological synovial fluids from human, canine and equine sources, we have demonstrated the presence of aggrecan catabolites that appear to have resulted from similar C-terminal processing of aggrecan as that induced in our in vitro culture systems. Finally, by developing a new MAb recognizing a linear epitope in the IGD of aggrecan, we have identified two novel aggrecan metabolites generated by an as yet unidentified proteolytic event. Collectively, these results suggest that C-terminal processing of aggrecan by MMPs may contribute to the depletion of cartilage GAG that leads to loss of tissue function in aging and disease. Furthermore, analysis of aggrecan metabolites resulting from both C-terminal and IGD cleavage by MMPs may prove useful in monitoring different stages in the progression of cartilage degeneration.     

Economic Burden of Heart Failure: Investigating Outpatient and Inpatient Costs in Abeokuta,Southwest Nigeria

Background: Heart failure (HF) is a deadly, disabling and often costly syndrome world-wide. Unfortunately, there is a paucity of data describing its economic impact in sub Saharan Africa; a region in which the number of relatively younger cases will inevitably rise. Methods: Heath economic data were extracted from a prospective HF registry in a tertiary hospital situated in Abeokuta, southwest Nigeria. Outpatient and inpatient costs were computed from a representative cohort of 239 HF cases including personnel, diagnostic and treatment resources used for their management over a 12-month period. Indirect costs were also calculated. The annual cost per person was then calculated. Results: Mean age of the cohort was 58.0±15.1 years and 53.1% were men. The total computed cost of care of HF in Abeokuta was 76, 288,845 Nigerian Naira (US$508, 595) translating to 319,200 Naira (US$2,128 US Dollars) per patient per year. The total cost of in-patient care (46% of total health care expenditure) was estimated as 34,996,477 Naira (about 301,230 US dollars). This comprised of 17,899,977 Naira- 50.9% ($US114,600) and 17,806,500 naira −49.1%($US118,710) for direct and in-direct costs respectively. Out-patient cost was estimated as 41,292,368 Naira ($US 275,282). The relatively high cost of outpatient care was largely due to cost of transportation for monthly follow up visits. Payments were mostly made through out-of-pocket spending. Conclusion: The economic burden of HF in Nigeria is particularly high considering, the relatively young age of affected cases, a minimum wage of 18,000 Naira ($US120) per month and considerable component of out-of-pocket spending for those affected. Health reforms designed to mitigate the individual to societal burden imposed by the syndrome are required.     

Homocysteine from endothelial cells promotes LDL nitration and scavenger receptor uptake

We recently reported that methionine-loaded human umbilical vein endothelial cells (HUVECs) exported homocysteine (Hcy) and were associated with hydroxyl radical generation and oxidation of lipids in LDL. Herein we have analysed the Hcy-induced posttranslational modifications (PTMs) of LDL protein. PTMs have been characterised using electrophoretic mobility shift, protein carbonyl ELISA, HPLC with electrochemical detection and Western blotting of 3-nitrotyrosine, and LDL uptake by scavenger receptors on monocyte/macrophages. We have also analysed PTMs in LDL isolated from rheumatoid (RA) and osteo-(OA) arthritis patients with cardiovascular disease (CVD). While reagent Hcy (< 50 microM) promoted copper-catalysed LDL protein oxidation, Hcy released from methionine-loaded HUVECs promoted LDL protein nitration. In addition, LDL nitration was associated with enhanced monocyte/macrophage uptake when compared with LDL oxidation. LDL protein nitration and uptake by monocytes, but not carbonyl formation, was elevated in both RA and OA patients with CVD compared with disease-matched patients that had no evidence of CVD. Moreover, a direct correlation between plasma total Hcy (tHcy) and LDL uptake was observed. The present studies suggest that elevated plasma tHcy may promote LDL nitration and increased scavenger receptor uptake, providing a molecular mechanism that may contribute to the clinical link between CVD and elevated plasma tHcy.     

Oral mucosal lesions and temporomandibular joint impairment of elderly people in the South East Local Government Area of Ibadan

Objective: To determine the prevalence of oral mucosal lesions, temporomandibular joint (TMJ) impairment and oral health‐related habits in the elderly people in South East Local Government Area (SELGA) in Ibadan. Background data: SELGA is one of the largest local government areas in Oyo State, Nigeria and has a population of 225 800. Design: A cross‐sectional survey. Methodology: A randomly selected sample of 690 elderly people from 23 wards in SELGA were examined by two trained and calibrated examiners using mirror, probe and natural light. Results: One hundred and fifty‐five (22.46%) of the elderly examined had one or more oral pathology lesions, representing infection‐related swelling, non‐infection‐related swelling, pre‐malignant lesions, denture stomatitis, non‐denture based ulcers, angular cheilitis, geographic tongue, scrotal tongue, lichen planus, hyper‐pigmentation and TMJ impairment. Fifty‐five (35.5%) of these pathologies were infection‐related swellings. Six (3.9%) of the pathologies were denture‐related stomatitis, 14(9.03%) were pre‐malignant lesions, 14(9.03%) were non‐infection‐related swelling, while 27 (17.4%) were TMJ impairment. The rest of the lesions constituted the remaining 25.1%. Only 15.9% of the participants had tobacco‐related habits, 10.7% drank alcohol, whilst 41.6% chewed kola nuts. Conclusion: Oral pathoses prevalence (22.46%) was similar to findings in developed countries (29.9%) but with a reversal of causal factors, infection‐related swellings were more common, whereas pre‐malignant lesions were less common. The infections were mostly complications from periodontal disease, which culminated in abscess formation. Tobacco‐related habits were not highly prevalent among the elderly people in SELGA. However, oral pathoses resulting from nutritional deficiencies were the third most frequent lesions observed.