Oxadiazols: a new class of rationally designed anti-human immunodeficiency virus compounds targeting the nuclear localization signal of the viral matrix protein

Despite recent progress in anti-human immunodeficiency virus (HIV) therapy, drug toxicity and emergence of drug-resistant isolates during long-term treatment of HIV-infected patients necessitate the search for new targets that can be used to develop novel antiviral agents. One such target is the process of nuclear translocation of the HIV preintegration complex. Previously we described a class of arylene bis(methylketone) compounds that inhibit HIV-1 nuclear import by targeting the nuclear localization signal (NLS) in the matrix protein (MA). Here we report a different class of MA NLS-targeting compounds that was selected using computer-assisted drug design. The leading compound from this group, ITI-367, showed potent anti-HIV activity in cultures of T lymphocytes and macrophages and also inhibited HIV-1 replication in ex vivo cultured lymphoid tissue. The virus carrying inactivating mutations in MA NLS was resistant to ITI-367. Analysis by real-time PCR demonstrated that the compound specifically inhibited nuclear import of viral DNA, measured by two-long terminal repeat circle formation. Evidence of the existence of this mechanism was provided by immunofluorescent microscopy, using fluorescently labeled HIV-1, which demonstrated retention of the viral DNA in the cytoplasm of drug-treated macrophages. Compounds inhibiting HIV-1 nuclear import may be attractive candidates for further development.     

Root traits, nutrient uptake, multi-location grain yield and benefit–cost ratio of two lentil (Lens culinaris, Medikus.) varieties

Lentil is a protein-rich pulse, grown mainly in developing countries as a rain-fed crop in nutrient-poor soils. Hence, the importance of root traits for efficient capture of soil nutrients and water can be crucial to its economical yield. Little is known about the lentil root system and even less about its relationship to grain yield. We compared the root system of two Bangladeshi lentil varieties, Barimasur-3 (BM-3) and Barimasur-4 (BM-4), in a pot experiment and related it to their multi-location grain yield in the fields. BM-4 maintained faster root development both at an early growth stage (20days after sowing) and at flowering (60days) compared to BM-3. The roots of BM-4 penetrated the 25cm depth of the soil profile after 19±1days and while those of BM-3 took 24±2days to reach the same depth. The roots of BM-4 were covered with denser (26±3mm^–1) and longer (0.48±0.11) root hairs than BM-3 (density 17±2mm^–1, length 0.32±0.09mm). The differential presence of root hairs increased the effective length of root system of BM-4 by 12 times and that of BM-3 by five times. The lentil varieties did not differ in their ability to induce pH change and acid phosphatase activity in rhizosphere. In the pot experiment, the uptake of macro-nutrients (K, P, Ca, and Mg) as well as micro-nutrients (Fe, Mn, Zn, Cu, B and Mo) by BM-4 was significantly higher, compared to BM-3. The varieties produced the same amount of shoot biomass. At five of six agro-ecological distinct field locations in Bangladesh, BM-4 gave significantly higher (10–20%) grain yield than BM-3. Linked with the higher grain yield, the benefit-cost ratio (BCR) of BM-4 was 3.14 and that of BM-3 were 2.62, indicating that BM-4 provided better return per unit investment, compared to BM-3, supported by the better root morphology and higher nutrient uptake. This may be one of the reasons supporting the popularity and preferred adoption of BM-4 among the Bangladeshi farmers, who grow lentil mainly on nutrient-poor soils. The results indicate the benefits of selection and breeding for superior root traits for better agro-economics.     

Dual role of histamine in modulation of Leydig cell steroidogenesis via HRH1 and HRH2 receptor subtypes

Although several reports indicate effects of histamine (HA) on female reproductive functions, scant literature exists to suggest a physiological role of HA in the male gonad. In the present study, we report a dual concentration-dependent effect of HA on steroidogenesis in MA-10 murine Leydig cells and purified rat Leydig cells. Although 1 nM HA can stimulate steroid production and significantly increase the response to LH/hCG in these cells, 10 microM HA exerts an inhibitory effect. We also provide confirming evidence for the existence of functional HRH1 and HRH2 receptors in both experimental models. The use of HRH1 and HRH2 selective agonists and antagonists led us to suggest that HRH2 activation would be largely responsible for stimulation of steroidogenesis, while HRH1 activation is required for inhibition of steroid synthesis. Our results regarding signal transduction pathways associated with these receptors indicate the coupling of HRH2 to the adenylate cyclase system through direct interaction with a Gs protein. Moreover, we show HRH1 activation mediates increases in inositol phosphate production, possibly due to coupling of this receptor to Gq protein and phospholipase C activation. The data compiled in this report clearly indicate that HA can modulate Leydig cell steroidogenesis in the testis and suggest a possible new physiological site of action for HA. Given that many drugs binding to HRH1, HRH2, or both, are widely prescribed for the treatment of diverse HA-related pathologies, it seems necessary to increase the knowledge regarding histaminergic regulation of testicular functions, to avoid possible unexpected side effects of such substances in the testis.     

Association between the APOE*4 allele and atherosclerosis is age dependent among Argentine males

Several studies have shown evidence of an association between the *4 allele of apolipoprotein E (APOE) and coronary heart disease (CHD) in different populations. We determined the APOE genotype and total cholesterol (TC), triglycerides (TG), and high-density lipoprotein cholesterol (HDLC) values in 189 patients with angiographically evaluated atherosclerosis. The APOE*4 allele was found to be statistically significantly more frequent (odds ratio, 1.93; 95% confidence interval, 1.12-3.32) among male patients than in a randomly chosen population-based sample. No significant difference was found when female patients were compared to the general population. The APOE*4 allele was found primarily among young (30-45-year-old) male patients (p < 0.04). Despite the ascending linear tendency of the mean TC values for genotypes APOE*2/*3, APOE*3/*3, and APOE*3/ *4 reported in our case population, no differences were observed among our patients. We conclude that the APOE*4 allele is associated with an increased risk for atherosclerotic vascular disease, that this association has an age-dependent effect, and that it acts as a genetic factor that increases susceptibility to developing the disease in young to middle-aged male adults in our population.     

Optimization of culture conditions to obtain maximal growth of penicillin-resistant <Emphasis Type="Italic">Streptococcus pneumoniae</Emphasis>

Background  

Streptococcus pneumoniae, particularly penicillin-resistant strains (PRSP), constitute one of the most important causes of serious infections worldwide. It is a fastidious microorganism with exquisite nutritional and environmental requirements to grow, a characteristic that prevents the development of useful animal models to study the biology of the microorganism. This study was designed to determine optimal conditions for culture and growth of PRSP.     

Hydrogen peroxide is generated during the very early stages of aggregation of the amyloid peptides implicated in Alzheimer disease and familial British dementia

Alzheimer disease and familial British dementia are neurodegenerative diseases that are characterized by the presence of numerous amyloid plaques in the brain. These lesions contain fibrillar deposits of the beta-amyloid peptide (Abeta) and the British dementia peptide (ABri), respectively. Both peptides are toxic to cells in culture, and there is increasing evidence that early "soluble oligomers" are the toxic entity rather than mature amyloid fibrils. The molecular mechanisms responsible for this toxicity are not clear, but in the case of Abeta, one prominent hypothesis is that the peptide can induce oxidative damage via the formation of hydrogen peroxide. We have developed a reliable method, employing electron spin resonance spectroscopy in conjunction with the spin-trapping technique, to detect any hydrogen peroxide generated during the incubation of Abeta and other amyloidogenic peptides. Here, we monitored levels of hydrogen peroxide accumulation during different stages of aggregation of Abeta-(1-40) and ABri and found that in both cases it was generated as a short "burst" early on in the aggregation process. Ultrastructural studies with both peptides revealed that structures resembling "soluble oligomers" or "protofibrils" were present during this early phase of hydrogen peroxide formation. Mature amyloid fibrils derived from Abeta-(1-40) did not generate hydrogen peroxide. We conclude that hydrogen peroxide formation during the early stages of protein aggregation may be a common mechanism of cell death in these (and possibly other) neurodegenerative diseases.     

Plasmodium falciparum: evaluation of a quantitative nucleic acid sequence-based amplification assay to predict the outcome of sulfadoxine-pyrimethamine treatment of uncomplicated malaria

A quantitative nucleic acid sequence-based amplification (QT-NASBA) assay was employed to predict retrospectively the outcome of sulfadoxine-pyrimethamine (SP) treatment of uncomplicated malaria in children aged <6 years in an endemic region. Blood samples were collected at initial diagnosis and during follow-up. Mutation-specific nested PCR methods to analyse DHFR (Arg-59) and DHPS (Glu-540) mutations that are associated with SP drug resistance were applied. Parasite genotyping was performed to distinguish between re-infection and recrudescence. Eighty-six patients were recruited of which 66 were available for follow-up. Nine children were classified as early treatment failure, 13 cases were classified as late clinical failure, 32 as late parasitological failure, and only 12 children had an adequate clinical and parasitological response. DHFR and DHPS mutations conferring SP resistance were abundant in the Plasmodium population. Blood samples obtained 7 days after treatment were used to predict retrospectively the outcome of SP treatment. QT-NASBA was able to give a correct prediction of treatment outcome in 85.7% of the cases. Positive predictive value (PPV) of QT-NASBA case was 95% (95% confidence interval = 88.3-100) and negative predictive value (NPV) was 63% (95% CI = 39.5-86.5). In contrast, microscopy correctly predicted outcome in only 37.5% of the cases. PPV of microscopy was 100% (95% CI = 73.9-100) and the NPV was 25.5% (95% CI = 13.0-38.0). The analysis of a day 7 blood sample with QT-NASBA allows for the prediction of late clinical or parasitological treatment failure in the majority of the cases analysed in the present study.     

Conservation Genetics of the East Pacific Green Turtle (Chelonia mydas) in Michoacan, Mexico

The main continental nesting rookeries of the east Pacific green turtle (EPGT), Chelonia mydas, on the Michoacan (Mexico) coast suffered drastic population declines following intense exploitation in the 1960s--1970s with annual abundance of nesting females plummeting from about 25,000 to an average of about 1400 between 1982 and 2001. Analyses of data from three nDNA microsatellite loci and 400 bp mtDNA control region sequences from a total of 123 nesting females sampled from four Michoacan rookeries found no evidence of population sub-structuring. The recent order of magnitude reduction in the population size shows no apparent impact on genetic diversity in either control region sequences (overall h = 0.48; pi = 0.0036) or microsatellite loci (overall Na = 20.8; Hexp = 0.895). Our estimates of annual effective female population size (Nef; from theta = 2Nemicron) of 1.9-2.3 x 10(3), in spite of being an order of magnitude below historical records, appear to be sufficient to allow recovery of this population without significant loss of genetic diversity. These findings highlight the importance of continued conservation to reverse the decline of this population before it becomes vulnerable to genetic erosion.