Properties and attempted culture of Pasteuria penetrans, a bacterial parasite of root-knot nematode (Meloidogyne javanica)

When they were subjected to a range of physical and chemical treatments, spores of Pasteuria penetrans showed properties similar to those of other endospore-forming bacteria. The spores did not take up some stains, were resistant to desiccation and sonication and showed extrusion of spore contents ('spore popping') on prolonged exposure to 0.1% KMnO₄ in 0.3 n HNO₃. Calcium and dipicolinic acid (DPA) were present at concentrations of 0.28% and 0.96% of the spore dry weight respectively, giving a Ca: DPA molar ratio of 1.2. The infectivity of P. penetrans spores was reduced to a low level after heating at 100°C for 5 min, but spore attachment was not markedly affected by heating at 100°C for 15 min. Evidence for the presence of catalase in P. penetrans spores was equivocal because the low levels of catalase activity observed in spore suspensions may have been due to contamination from catalase-positive nematode tissue. When P. penetrans spores were exposed to a range of substances known to act as germinants for spores of Bacillus spp., germination or loss of refractility was not observed by phase microscopy. In vitro culture of P. penetrans was attempted by inoculating either spores or vegetative mycelial bodies onto a diverse range of simple and complex media and incubating them in aerobic, reduced oxygen, anaerobic and increased CO₂ environments. Signs of spore germination or growth of vegetative stages were never observed.     

Predictors of Treatment Response to Tesamorelin,a Growth Hormone-Releasing Factor Analog,in HIV-Infected Patients with Excess Abdominal Fat

BackgroundTesamorelin, a synthetic analog of human growth hormone-releasing factor, decreases visceral adipose tissue (VAT) in human immunodeficiency virus (HIV)-infected patients with lipodystrophy.Objectives1) To evaluate the utility of patient characteristics and validated disease-risk scores, namely indicator variables for the metabolic syndrome defined by the International Diabetes Federation (MetS-IDF) or the National Cholesterol Education Program (MetS-NCEP) and the Framingham Risk Score (FRS), as predictors of VAT reduction during tesamorelin therapy at 3 and 6 months, and 2) To explore the characteristics of patients who reached a threshold of VAT <140 cm², a level associated with lower risk of adverse health outcomes, after 6 months of treatment with tesamorelin.MethodsData were analyzed from two Phase 3 studies in which HIV-infected patients with excess abdominal fat were randomized in a 2:1 ratio to receive tesamorelin 2 mg (n = 543) or placebo (n = 263) subcutaneously daily for 6 months, using ANOVA and ANCOVA models.ResultsMetabolic syndrome (MetS-IDF or MetS-NCEP) and FRS were significantly associated with VAT at baseline. Presence of metabolic syndrome ([MetS-NCEP), triglyceride levels >1.7 mmol/L, and white race had a significant impact on likelihood of response to tesamorelin after 6 months of therapy (interaction p-values 0.054, 0.063, and 0.025, respectively). No predictive factors were identified at 3 months. The odds of a VAT reduction to <140 cm² for subjects treated with tesamorelin was 3.9 times greater than that of subjects randomized to placebo after controlling for study, gender, baseline body mass index (BMI) and baseline VAT (95% confidence interval [CI] 2.03; 7.44).ConclusionsIndividuals with baseline MetS-NCEP, elevated triglyceride levels, or white race were most likely to experience reductions in VAT after 6 months of tesamorelin treatment. The odds of response of VAT <140 cm² was 3.9 times greater for tesamorelin-treated patients than that of patients receiving placebo.     

Large scale international replication and meta-analysis study confirms association of the 15q14 locus with myopia. The CREAM consortium

Myopia is a complex genetic disorder and a common cause of visual impairment among working age adults. Genome-wide association studies have identified susceptibility loci on chromosomes 15q14 and 15q25 in Caucasian populations of European ancestry. Here, we present a confirmation and meta-analysis study in which we assessed whether these two loci are also associated with myopia in other populations. The study population comprised 31 cohorts from the Consortium of Refractive Error and Myopia (CREAM) representing 4 different continents with 55,177 individuals; 42,845 Caucasians and 12,332 Asians. We performed a meta-analysis of 14 single nucleotide polymorphisms (SNPs) on 15q14 and 5 SNPs on 15q25 using linear regression analysis with spherical equivalent as a quantitative outcome, adjusted for age and sex. We calculated the odds ratio (OR) of myopia versus hyperopia for carriers of the top-SNP alleles using a fixed effects meta-analysis. At locus 15q14, all SNPs were significantly replicated, with the lowest P value 3.87?×?10(-12) for SNP rs634990 in Caucasians, and 9.65?×?10(-4) for rs8032019 in Asians. The overall meta-analysis provided P value 9.20?×?10(-23) for the top SNP rs634990. The risk of myopia versus hyperopia was OR 1.88 (95?% CI 1.64, 2.16, P?相似文献   

Decline in rate of death from ischaemic heart disease in the United Kingdom.

The rates of death from ischaemic heart disease in the United Kingdom in the years after 1968 were studied to establish whether any general trend had occurred. A decline in the rates began after 1973-4, was greatest in those aged 35-44 years, and occurred among both men and women and in each of the regions of England and in Wales and Scotland. Total dietary fat intake had started to fall about five years earlier, and this may provide part of the explanation. Changes in smoking habits also occurred but were more difficult to relate to the pattern of change in the death rates. If a general decline in ischaemic heart disease has begun in the United Kingdom a case may be made for close monitoring of changes in lifestyle and medical practice in different demographic groups to try to find the explanation.     

Phylogenetic analysis of feline immunodeficiency virus in feral and companion domestic cats of New Zealand

Nested PCR was used to amplify envelope V3-V6 gene fragments of feline immunodeficiency virus (FIV) from New Zealand cats. Phylogenetic analyses established that subtypes A and C predominate among New Zealand cats, with clear evidence of intersubtype recombination. In addition, 17 sequences were identified that were distinct from all known FIV clades, and we tentatively suggest these belong to a novel subtype.     

Factors influencing the distribution of Subantarctic deep-sea benthic foraminifera,Campbell and Bounty Plateaux,New Zealand

We investigate the combination of environmental factors that influence the distribution patterns of benthic foraminiferal tests (> 63 μm) in a topographically varied region crossed by both the Subtropical and Subantarctic Fronts, south-east of New Zealand. Seafloor sample sites, extending from outer shelf (50 m) to abyssal (5000 m) depths, are bathed by five different water masses, and receive phytodetritus from Subtropical, Subantarctic and Circumpolar surface water masses. Eight mappable associations are recognised by Q-mode cluster analysis of the benthic foraminiferal census data. Similar associations are identified using cluster analysis based solely on the presence or absence of species. Canonical correspondence analysis and a correlation coefficient matrix were used to relate the faunal data to a set of environmental proxies. These show that factors related to water depth (especially decreasing food supply with increasing depth) are the most significant in determining the overall foraminiferal distribution. Other contributing factors include surface water productivity and its seasonality; bottom water ventilation; energetic state of the benthic boundary layer and resulting substrate texture; and bottom water carbonate corrosiveness. Three shallow-water associations (50–700 m), dominated by Cassidulina carinata, Trifarina angulosa, Globocassidulina canalisuturata, Gavelinopsis praegeri, and Bolivina robusta, occur in coarse substrates on the continental shelf, and on the crests and upper slopes of four seamounts under well-oxygenated, high energy regimes, and high food input. Three mid bathyal to upper abyssal associations (500–3300 m), dominated by Alabaminella weddellensis, C. carinata, and Epistominella exigua, occur in biopelagic sandy mud, beneath a region of strongly seasonal food supply, with their composition influenced by total food flux, ventilation (Oxygen Minimum Zone), and bottom current strength. An unusual lower bathyal association (1200–2100 m), dominated by T. angulosa and Ehrenbergina glabra, occurs in a belt of coarser sandy substrate that runs along the crest of the submarine plateaux slopes beneath the strongly-flowing Subantarctic Front-related currents. A deep abyssal association (3500–5000 m), dominated by Nuttallides umbonifer and Globocassidulina subglobosa, occurs on the abyssal plain beneath oligotrophic lower Circumpolar Water south-east of the Subantarctic Front and is strongly influenced by the cold, carbonate-corrosive conditions.     

Essential dynamics sampling study of adenylate kinase: comparison to citrate synthase and implication for the hinge and shear mechanisms of domain motions

Essential dynamics sampling simulations of the domain conformations of unliganded Escherichia coli adenylate kinase have been performed to determine whether the ligand-induced closed-domain conformation is accessible to the open unliganded enzyme. Adenylate kinase is a three- domain protein with a central CORE domain and twoflanking domains, the LID and the NMPbind domains. The sampling simulations were applied to the CORE and NMPbind domain pair and the CORE and LID domain pair separately. One aim is to compare the results to those of a similar study on the enzyme citrate synthase to determine whether a similar domain-locking mechanism operates in adenylate kinase. Although for adenylate kinase the simulations suggest that the closed-domain conformation of the unliganded enzyme is at a slightly higher free energy than the open for both domain pairs, the results are radically different to those found for citrate synthase. In adenylate kinase the targeted domain conformations could always be achieved, whereas this was not the case in citrate synthase due to an apparent free-energy barrier between the open and closed conformations. Adenylate kinase has been classified as a protein that undergoes closure through a hinge mechanism, whereas citrate synthase has been assigned to the shear mechanism. This was quantified here in terms of the change in the number of interdomain contacting atoms upon closure which showed a considerable increase in adenylate kinase. For citrate synthase this number remained largely the same, suggesting that the domain faces slide over each other during closure. This suggests that shear and hinge mechanisms of domain closure may relate to the existence or absence of an appreciable barrier to closure for the unliganded protein, as the latter can hinge comparatively freely, whereas the former must follow a more constrained path. In general though it appears a bias toward keeping the unliganded enzyme in the open-domain conformation may be a common feature of domain enzymes.