DNA protection by histone-like protein HU from the hyperthermophilic eubacterium Thermotoga maritima

In mesophilic prokaryotes, the DNA-binding protein HU participates in nucleoid organization as well as in regulation of DNA-dependent processes. Little is known about nucleoid organization in thermophilic eubacteria. We show here that HU from the hyperthermophilic eubacterium Thermotoga maritima HU bends DNA and constrains negative DNA supercoils in the presence of topoisomerase I. However, while binding to a single site occludes approximately 35 bp, association of T. maritima HU with DNA of sufficient length to accommodate multiple protomers results in an apparent shorter occluded site size. Such complexes consist of ordered arrays of protomers, as revealed by the periodicity of DNase I cleavage. Association of TmHU with plasmid DNA yields a complex that is remarkably resistant to DNase I-mediated degradation. TmHU is the only member of this protein family capable of occluding a 35 bp nonspecific site in duplex DNA; we propose that this property allows TmHU to form exceedingly stable associations in which DNA flanking the kinks is sandwiched between adjacent proteins. We suggest that T. maritima HU serves an architectural function when associating with a single 35 bp site, but generates a very stable and compact aggregate at higher protein concentrations that organizes and protects the genomic DNA.     

Radiological toxicity of some fish and meat tissues consumed in southwestern Nigeria

The activity concentrations of natural radionuclides in 30 fish tissues and 30 meat organs have been determined using high purity germanium (HPGe) detector. For the fish tissues, the mean activity concentrations of ²³⁸U and ²³²Th were highest in Catfish (Clarias gariepinus) with values of 5.31 ± 1.30 and 6.09 ± 0.91 Bq/kg, respectively. The lowest mean activity concentrations of ²³⁸U and ²³²Th were seen in Titus (Scomberomorus tritor) and Croaker (Micropogonias undulatus), Croaker with values of 1.51 ± 2.08 and 64.42 ± 6.33 Bq/kg, respectively. The mean activity concentration of ⁴⁰K was highest in Micropogonias undulatus and lowest in Tilapia (Oreohronis niloticus) with values of 64.42 ± 6.33 and 6.53 ± 0.98 Bq/kg. For the meat organs, the highest mean activity concentration of ²³⁸U, ²³²Th, and ⁴⁰K was highest in kidney, liver, and heart, respectively with values of 2.82 ± 0.47, 4.57 ± 0.69, and 52.07 ± 7.81 Bq/kg. Small intestine had the lowest mean activity concentrations of ²³⁸U and ²³²Th with values of 1.14 ± 0.16 and 0.89 ± 0.08 Bq/kg, respectively. Beef had the lowest mean activity concentration of ⁴⁰K with a value of 17.61 ± 2.14 Bq/kg.     

Morin Attenuates Neurochemical Changes and Increased Oxidative/Nitrergic Stress in Brains of Mice Exposed to Ketamine: Prevention and Reversal of Schizophrenia-Like Symptoms

Previous studies have revealed that morin (MOR), a neuroactive bioflavonoid, with proven psychotropic and neuroprotective properties reduced schizophrenic-like behaviors in mice. This study further evaluated the ability of MOR to prevent and reverse ketamine-induced schizophrenic-like behaviors and the underlying neurochemical changes and increased oxidative/nitrergic stress in mice. In the preventive protocol, mice received intraperitoneal injection of MOR (100 mg/kg), reference antipsychotic drugs [haloperidol (1 mg/kg), risperidone (0.5 mg/kg)], or saline daily for 14 consecutive days prior to i.p. injection of ketamine (KET) (20 mg/kg/day) from the 8th to the 14th day. In the reversal protocol, the animals received KET or saline for 14 days prior to MOR, haloperidol, risperidone, or saline treatments. Schizophrenic-like behaviors: positive (open-field test), negative (social-interaction test) and cognitive (Y-maze test) symptoms were evaluated. Thereafter, the brain levels of dopamine, glutamate, 5-hydroxytryptamine and acetyl-cholinesterase, as well as biomarkers of oxidative/nitrergic stress were measured in the striatum, prefrontal-cortex (PFC) and hippocampus (HC). Morin prevented and reversed KET-induced hyperlocomotion, social and cognitive deficits. Also, MOR or risperidone attenuated altered dopaminergic, glutamatergic, 5-hydroxytryptaminergic and cholinergic neurotransmissions in brain region-dependent manner. The increased malondialdehyde and nitrite levels accompanied by decreased glutathione concentrations in the striatum, PFC and HC in KET-treated mice were significantly attenuated by MOR or risperidone. Taken together, these findings suggest that the anti-schizophrenic-like activity of MOR may be mediated via mechanisms related to attenuation of neurochemical changes and oxidative/nitrergic alterations in mice.     

Genotypes of Cryptosporidium spp. and Enterocytozoon bieneusi in Human Immunodeficiency Virus‐Infected Patients in Lagos,Nigeria

Molecular characterization of Cryptosporidium spp. and Enterocytozoon bieneusi has improved our understanding of the transmission of both organisms in humans. In this study, to infer possible infection sources, Cryptosporidium spp. and E. bieneusi in fecal specimens from 90 HIV‐infected patients attending antiretroviral clinics in Lagos, Nigeria were detected and genotyped by PCR and DNA sequencing. Cryptosporidium spp. and E. bieneusi were identified in four and five patients, respectively, including the occurrence of subtype IeA11T3G3 of Cryptosporidium hominis in two patients, subtype IIcA5G3k of Cryptosporidium parvum in one patient, and Type IV of E. bieneusi in four patients. Among the remaining positive patients, one had mixed infection of Cryptosporidium meleagridis and C. hominis and one had mixed E. bieneusi genotypes. These data highlight a possible difference in major transmission routes (anthroponotic vs. zoonotic) between Cryptosporidium spp. and E. bieneusi in HIV+ patients in the study area.     

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     

The PDZ1 and PDZ3 Domains of MAGI-1 Regulate the Eight-Exon Isoform of the Coxsackievirus and Adenovirus Receptor

Epithelial integrity is essential for homeostasis and poses a formidable barrier to pathogen entry. Major factors for viral entry into epithelial cells are the localization and abundance of the primary receptor. The coxsackievirus and adenovirus receptor (CAR) is a primary receptor for these two pathogenic groups of viruses. In polarized epithelia, a low-abundance, alternatively spliced eight-exon isoform of CAR, CAR(Ex8), is localized apically where it can support viral infection from the air-exposed surface. Using biochemical, cell biology, genetic, and spectroscopic approaches, we show that the levels of apical CAR(Ex8) are negatively regulated by the PDZ domain-containing protein MAGI-1 (membrane-associated guanylate kinase with inverted orientation protein-1) and that two MAGI-1 PDZ domains, PDZ1 and PDZ3, regulate CAR(Ex8) levels in opposing ways. Similar to full-length MAGI-1, expression of the isolated PDZ3 domain significantly reduces cell surface CAR(Ex8) abundance and adenovirus infection. In contrast, the PDZ1 domain is able to rescue CAR(Ex8) and adenovirus infection from MAGI-1-mediated suppression. These data suggest a novel cell-based strategy to either suppress viral infection or augment adenovirus-based gene therapy.     

Assessment of women's risk factors for breast cancer and predictors of the practice of breast examination in two rural areas near Ibadan,Nigeria

Objective: In Nigeria, breast cancer is the most common cancer among women in majority of the regions. Late presentation has also been reported for about four decades. This study assessed the women's risk factors for breast cancer and predictive factors for the practice of breast examinations. The findings will be of help in enhancing early detection of the disease and reducing mortality from the disease. Methods: Utilizing a multi-stage sampling method, 420 women were selected at Akinyele Local government area of Ibadan. Data was collected with questionnaire. The risk factor was evaluated using the breast cancer risk assessment tool based on the Gail model. Six demographic factors, plus four covariates: knowledge of BSE/CBE, knowledge of the cause of, symptoms and signs of and treatment of breast cancer, were regressed against two dependent variables of practice of BSE and CBE using linear regression and binary logistic analyses respectively. Results: Only 386 questionnaires properly filled were analyzed. The mean age of respondents was 37.3 (SD = 13.1) years. They were of low educational status and were mostly traders and married. Only 190 of the women fulfilled the criteria for assessment with the Gail model. Most of the women, 180 (94.7%), had five years and 184 (96.8%) had lifetime risks lower than that of the average woman of the same age. Four significant predictors of BSE were marital status (p = 0.004), educational status (p = 0.018), knowledge of treatment of breast cancer (p = 0.029) and knowledge of BSE/CBE (p = 0.0001) while no formal education status and being a farmer were the only significant predictors of CBE. Conclusions: The findings are useful for planning interventional studies to enhance early detection in a low resource country.     

Effect of fungal enzyme mixture supplementation of various fibre-containing diets fed to broiler chicks 2: On blood,liver and kidney total lipids,triacylglycerols and cholesterol

Broiler chicks of both sexes were fed formulated rations containing different fibre types with and without supplementation with crude and pure microbial enzymes in order to determine the effect on the lipids of the blood, liver and kidney. Results shown enzyme supplementation to greatly and significantly affect total lipid, free fatty acids, triglyceride and cholesterol levels of the blood, liver and kidney relative to the age of the birds and the type of fibres. By day 42, the total blood lipid of the unsupplemented diet rose to the highest level (22.4 mg/l), that of the kidney (3.62 mg/g) and the liver (185.7 mg/g). Enzyme supplementation, however, brought about reduction of these values with the diet containing all the fibres – wheat bran, corn bran, palm kernel meal and coconut meal giving the lowest values of the total lipids, free fatty acids, triglycerides and cholesterol on day 42 for the blood, liver and kidney, respectively. The pure forms of the enzymes applied directly to the feed gave more highly significant effects than the crude forms fed through water. Interaction effects between the various forms of the enzyme and the mode of application were also statistically significant.