Entomophthora apiculata (Thaxter) Gustafs. (Zygomycetes,Entomophthorales) as a pathogen of calypterate flies in Nigeria

Entomophthora apiculata (Thaxter) Gustafs. was isolated from the following naturally-infected dipterans: Musca domestica L. (s.l.) (Muscidae); Hemipyrellia fernandica Macquart and Chrysomya chloropyga f. putoria Weidemann (Calliphoridae). This fungus produced rhizoids in vivo but not in vitro. Although it was readily cultured in vitro, experimental infection could not be achieved consistently — which calls for intensive research into the biology of this and other Entomophthora species.     

Moringa oleifera leaf fractions attenuated Naje haje venom-induced cellular dysfunctions via modulation of Nrf2 and inflammatory signalling pathways in rats

Naja haje envenoming could activate multiple pathways linked to haematotoxic, neurological, and antioxidant systems dysfunctions. Moringa oleifera has been used in the management of different snake venom-induced toxicities, but there is no scientific information on its antivenom effects against Naja haje. This study thus, investigated the antivenom activities of different extract partitions of M. oleifera leaves against N. haje envenoming. Forty five male rats were divided into nine groups (n = 5). Groups 2 to 9 were envenomed with 0.025 mg/kg (LD₅₀) of N. haje venom while group 1 was given saline. Group 2 was left untreated, while group 3 was treated with polyvalent antivenom, groups 4, 6 and 8 were treated with 300 mg/kg^?1 of N-hexane, ethylacetate and ethanol partitions of M. oleifera, respectively. Groups 5, 7 and 9 were also treated with 600 mgkg^?1of the partitions, respectively. Ethanol extract and ethyl acetate partition of M. oleifera significantly improved haematological indices following acute anaemia induced by the venom. Likewise, haemorrhagic, haemolytic and anti-coagulant activities of N. haje venom were best inhibited by ethanol partition. Envenoming significantly down-regulated Nuclear factor erythroid 2-related factor 2 (Nrf2) with the consequent elevation of antioxidant enzymes activities in the serum and brain. Treatment with extract partitions however, elevated Nrf2 levels while normalising antioxidant enzyme activities. Furthermore, there were reduction in levels of pro-inflammatory cytokines (TNF-α and interleukin-1β) in tissues of treated envenomed rats. This study concludes that ethanol partition of M. oleifera was most effective against N. haje venom and could be considered as a potential source for antivenom metabolites.     

Bioaccessibility-Based Risk Assessment of PAHs in Soils from Sites of Different Anthropogenic Activities in Lagos,Nigeria Using the Fed Organic Estimation Human Simulation Test Method

The aim of this study was to carry out a bioaccessibility-based risk assessment of polycyclic aromatic hydrocarbons (PAHs) in soils from sites of different anthropogenic activities in Lagos, Nigeria. Using an in vitro gastrointestinal model—Fed Organic Estimation Human Simulation Test method (FOREShT), the concentration of bioaccessible 16 priority US Environmental Protection Agency (USEPA) PAHs in soils were determined. Total concentration of 16 priority USEPA PAHs was also determined. The concentration range was 702–253,922 ng g^?1 and 92–760 ng g^?1 for total and bioaccessible PAHs, respectively. For persons involved with activities at these sites no health risks were observed, based on bioaccessibility values of PAHs. Mean daily intake of PAHs from these soils were below the oral mean daily intake threshold for PAHs in food. Also, overall estimated theoretical cancer risk (2.5 × 10^?09, 6.5 × 10^?07, 5.5 × 10^?10, 2.7 × 10^?09, 6.5 × 10^?10, 9.5 × 10^?10, 2.0 × 10^?09, and 4.1 × 10^?07 for the eight sites based on their bioaccessible concentration) for exposure to PAHs in surface soils were below the health guidelines for extreme (1 × 10^?04) and normal (1 × 10^?06) exposures.     

Dihydrochalcones from Uvaria angolensis

An investigation of the roots of Uvaria angolensis has led to the isolation and identification of two new dihydrochalcones, angoletin and uvangoletin, and the known C-benzyldihydrochalcones, uvaretin and isouvaretin. The structures were established from ¹³C NMR comparisons with known dihydrochalcones.     

Pollution characteristics and health risk assessment of potentially toxic elements in school playground soils: A case study of Lagos,Nigeria

Abstract

Soil samples were collected in February 2014 from 25 school playgrounds in Lagos, Nigeria to assess the potential adverse effects of the exposure of children to potentially toxic element (PTE). In each of the playgrounds, about 500?g of bulked soil samples were collected, dried, sieved, acid digested, and analyzed by inductively coupled plasma mass spectrometry (ICP‐MS). Results showed that soils studied were characteristically unpolluted as the average PTE concentration at each site did not exceed the soil guideline values. Considering the pollution assessment tools employed, some soil samples showed some form of anthropogenic input from PTE. Health risk assessment was employed to assess PTE exposure from ingestion, inhalation, and dermal contact. Result indicated that the highest risk is associated with ingestion followed by dermal contact and inhalation. For non‐carcinogenic effects, exposure to school playground soils poses no threat to children as the overall value of hazard index is less than the safe level of 1. For carcinogenic effects, only Cr and Ni were considered and were below the threshold of 1?×?10^–6. This study has demonstrated that minimal risk arises from the investigated playgrounds and that regular monitoring is required to keep the PTE contents low in soils to avoid risk to human health.

Abbreviations: SH, school playground; PTE, potentially toxic elements     

Flavonols and an oxychromonol from Piliostigma reticulatum

The leaf extract from the plant Piliostigma reticulatum was found to exhibit antimicrobial activity against some bacteria and fungi such as Staphylococcus aureus (NCTC 6571), Escherichia coli (NCTC 10418), Bacillus subtilis (NCTC 8236), Proteus vulgaris (NCTC 4175), Aspergillus niger (ATCC 10578) and Candida albicans (ATCC 10231). Upon investigation of the chemical constituents present in the leaf extract, a total of seven compounds were isolated and their structures were unambiguously established by spectroscopic methods including HR-MS and NMR spectrometry. Four of the isolated compounds were novel, namely 6-C-methyl-2-p-hydroxyphenyloxychromonol (piliostigmol), 1, 6,8-di-C-methylquercetin-3,3',7-trimethyl ether, 2, 6,8-di-C-methylquercetin-3,3'-dimethyl ether, 3 and 3',6,8,-tri-C-methylquercetin-3,7-dimethyl ether, 4. The other three were known C-methylated flavonols and they were isolated from P. reticulatum for the first time. These were 6-C-methylquercetin-3-methyl ether, 5, 6,8-di-C-methylkaempferol-3-methyl ether, 6 and 6-C-methylquercetin-3,3',7-trimethyl ether 7. All the isolated compounds were tested for cytotoxicity using the brine shrimp toxicity assay and all of them were active albeit at different levels. With respect to antibacterial activity piliostigmol, 1 showed the highest activity against E. coli (MIC=2.57 microg/ml, 0.006 micromol), which is three times more that of Amoxicillin, where as 4 and 7 showed the least activity.     

Synthesis and evaluation of inhibitors of bacterial drug efflux pumps of the major facilitator superfamily

Inhibitors of drug efflux pumps have great potential as pharmacological agents that restore the drug susceptibility of multidrug resistant bacterial pathogens. Most attention has been focused on the discovery of small molecules that inhibit the resistance nodulation division (RND) family drug efflux pumps in Gram-negative bacteria. The prototypical inhibitor of RND-family efflux pumps in Gram-negative bacteria is MC-207,110 (Phe-Arg-β-naphthylamide), a C-capped dipeptide. Here, we report that C-capped dipeptides inhibit two chloramphenicol-specific efflux pumps in Streptomyces coelicolor, a Gram-positive bacterium that is a relative of the human pathogen Mycobacterium tuberculosis. Diversity-oriented synthesis of a library of structurally related C-capped dipeptides via an Ugi four component reaction and screening of the resulting compounds resulted in the discovery of a compound that is threefold more potent as a suppressor of chloramphenicol resistance in S. coelicolor than MC-207,110. Since chloramphenicol resistance in S. coelicolor is mediated by major facilitator superfamily drug efflux pumps, our findings provide the first evidence that C-capped dipeptides can inhibit drug efflux pumps outside of the RND superfamily.     

Viral Cross-Class Serpin Inhibits Vascular Inflammation and T Lymphocyte Fratricide; A Study in Rodent Models In Vivo and Human Cell Lines In Vitro

Poxviruses express highly active inhibitors, including serine proteinase inhibitors (serpins), designed to target host immune defense pathways. Recent work has demonstrated clinical efficacy for a secreted, myxomaviral serpin, Serp-1, which targets the thrombotic and thrombolytic proteases, suggesting that other viral serpins may have therapeutic application. Serp-2 and CrmA are intracellular cross-class poxviral serpins, with entirely distinct functions from the Serp-1 protein. Serp-2 and CrmA block the serine protease granzyme B (GzmB) and cysteine proteases, caspases 1 and 8, in apoptotic pathways, but have not been examined for extracellular anti-inflammatory activity. We examined the ability of these cross-class serpins to inhibit plaque growth after arterial damage or transplant and to reduce leukocyte apoptosis. We observed that purified Serp-2, but not CrmA, given as a systemic infusion after angioplasty, transplant, or cuff-compression injury markedly reduced plaque growth in mouse and rat models in vivo. Plaque growth was inhibited both locally at sites of surgical trauma, angioplasty or transplant, and systemically at non-injured sites in ApoE-deficient hyperlipidemic mice. With analysis in vitro of human cells in culture, Serp-2 selectively inhibited T cell caspase activity and blocked cytotoxic T cell (CTL) mediated killing of T lymphocytes (termed fratricide). Conversely, both Serp-2 and CrmA inhibited monocyte apoptosis. Serp-2 inhibitory activity was significantly compromised either in vitro with GzmB antibody or in vivo in ApoE/GzmB double knockout mice. Conclusions The viral cross-class serpin, Serp-2, that targets both apoptotic and inflammatory pathways, reduces vascular inflammation in a GzmB-dependent fashion in vivo, and inhibits human T cell apoptosis in vitro. These findings indicate that therapies targeting Granzyme B and/or T cell apoptosis may be used to inhibit T lymphocyte apoptosis and inflammation in response to arterial injury.