Emended descriptions of Bacillus sporothermodurans and Bacillus oleronius with the inclusion of dairy farm isolates of both species

Bacillus sporothermodurans is an industrially important micro-organism because of its ability to produce endospores which resist ultra high temperature (UHT) and industrial sterilization processes. It was described by Pettersson et al. (1996) based on seven genetically homogeneous isolates all from UHT-milk. Bacillus oleronius, the closest phylogenetic neighbor of B. sporothermodurans, was described by Kuhnigk et al. (1995), based on a single strain, isolated from the hindgut of the termite Reticulitermes santonensis. A polyphasic study of a heterogeneous collection of B. sporothermodurans and B. oleronius strains isolated from various sources and geographic origins led to an emended description of both species. Additional data presented are the results of fatty acids, quinones and/or cell wall analysis (polar lipids). DNA-DNA hybridizations confirmed 3 subgroups of strains obtained after SDS-PAGE analysis of cellular proteins as B. sporothermodurans. One named B. sporothermodurans strain (R-7489) was reclassified as a Bacillus fordii strain. The phenotypic profiles of both species were rather heterogeneous, sometimes different from the original descriptions and did not differ in a large number of characters, although B. oleronius generally gave stronger reactions in its positive tests than did B. sporothermodurans; the variable and weak reactions for both organisms with some substrates blurred the distinction between both. However, differences in polar lipid, SDS-PAGE and menaquinone profiles clearly allow distinction between the two species

Genetic and pharmacological targeting of transcriptional repression in resistance to thyroid hormone alpha

Background Thyroid hormones act in bone and cartilage via thyroid hormone receptor α (TRα). In the absence of T3, TRα interacts with co-repressors, including nuclear receptor co-repressor-1 (NCoR1), which recruit histone deacetylases (HDACs) and mediate transcriptional repression. Dominant-negative mutations of TRα cause resistance to thyroid hormone α (RTHα; OMIM 614450), characterized by excessive repression of T3 target genes leading to delayed skeletal development, growth retardation and bone dysplasia. Treatment with thyroxine has been of limited benefit even in mildly affected individuals and there is a need for new therapeutic strategies. We hypothesized that (i) the skeletal manifestations of RTHα are mediated by the persistent TRα/NCoR1/HDAC repressor complex containing mutant TRα, and (ii) treatment with the HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) would ameliorate these manifestations. Methods We determined the skeletal phenotypes of (i) Thra1PV/+ mice, a well characterized model of RTHα, (ii) Ncor1ΔID/ΔID mice, which express an NCoR1 mutant that fails to interact with TRα, and (iii) Thra1PV/+Ncor1ΔID/ΔID double mutant adult mice. Wild-type, Thra1PV/+, Ncor1ΔID/ΔID, and Thra1PV/+Ncor1ΔID/ΔID double mutant mice were also treated with SAHA to determine whether HDAC inhibition results in amelioration of skeletal abnormalities. Results Thra1PV/+ mice had a severe skeletal dysplasia characterized by short stature, abnormal bone morphology and increased bone mineral content. Despite normal bone length, Ncor1ΔID/ΔID mice displayed increased cortical bone mass, mineralization and strength. Thra1PV/+Ncor1ΔID/ΔID double mutant mice displayed only a small improvement of skeletal abnormalities compared to Thra1PV/+ mice. Treatment with SAHA to inhibit histone deacetylation had no beneficial or detrimental effects on bone structure, mineralization or strength in wild-type or mutant mice. Conclusions These studies indicate treatment with SAHA is unlikely to improve the skeletal manifestations of RTHα. Nevertheless, the findings (i) confirm that TRα1 has a critical role in the regulation of skeletal development and adult bone mass, (ii) suggest a physiological role for alternative co-repressors that interact with TR in skeletal cells, and (iii) demonstrate a novel role for NCoR1 in the regulation of adult bone mass and strength

Optically trapped bacteria pairs reveal discrete motile response to control aggregation upon cell–cell approach

Aggregation of bacteria plays a key role in the formation of many biofilms. The critical first step is cell–cell approach, and yet the ability of bacteria to control the likelihood of aggregation during this primary phase is unknown. Here, we use optical tweezers to measure the force between isolated Bacillus subtilis cells during approach. As we move the bacteria towards each other, cell motility (bacterial swimming) initiates the generation of repulsive forces at bacterial separations of ~3 μm. Moreover, the motile response displays spatial sensitivity with greater cell–cell repulsion evident as inter-bacterial distances decrease. To examine the environmental influence on the inter-bacterial forces, we perform the experiment with bacteria suspended in Tryptic Soy Broth, NaCl solution and deionised water. Our experiments demonstrate that repulsive forces are strongest in systems that inhibit biofilm formation (Tryptic Soy Broth), while attractive forces are weak and rare, even in systems where biofilms develop (NaCl solution). These results reveal that bacteria are able to control the likelihood of aggregation during the approach phase through a discretely modulated motile response. Clearly, the force-generating motility we observe during approach promotes biofilm prevention, rather than biofilm formation

The per-protocol effect of immediate versus deferred antiretroviral therapy initiation

OBJECTIVE: The START trial found a lower risk of a composite clinical outcome in HIV-positive individuals assigned to immediate initiation of antiretroviral therapy (ART) compared with those assigned to deferred initiation. However, 30% of those assigned to deferred initiation started ART earlier than the protocol specified. To supplement the published intention-to-treat effect estimates, here we estimate the per-protocol effect of immediate versus deferred ART initiation in START. DESIGN: The START trial randomized 4685 HIV-positive participants with CD4 counts > 500 /mm to start ART immediately after randomization (immediate initiation group) or to wait until the CD4 count dropped below 350 cells/mm or an AIDS diagnosis (deferred initiation group). METHODS: We used the parametric g-formula to estimate and compare the cumulative 5-year risk of the composite clinical outcome in the immediate and deferred initiation groups had all the trial participants adhered to the protocol. RESULTS: We estimated that the 5-year risk of the composite outcome would have been 3.2% under immediate ART initiation and 7.0% under deferred initiation. The difference of 3.8% (95% confidence interval 1.5,6.5) was larger than the intention-to-treat effect estimate of 3.1%, corresponding to a difference in effect estimates of 0.72% (-0.35,2.35). CONCLUSIONS: The intention-to-treat effect estimate may underestimate the benefit of immediate ART initiation by 23%. This estimate can be used by patients and policy makers who need to understand the full extent of the benefit of changes in ART initiation policies

Heat shock factor-1 modulates p53 activity in the transcriptional response to DNA damage

Here we define an important role for heat shock factor 1 (HSF1) in the cellular response to genotoxic agents. We demonstrate for the first time that HSF1 can complex with nuclear p53 and that both proteins are co-operatively recruited to p53-responsive genes such as p21. Analysis of natural and synthetic cis elements demonstrates that HSF1 can enhance p53-mediated transcription, whilst depletion of HSF1 reduces the expression of p53-responsive transcripts. We find that HSF1 is required for optimal p21 expression and p53-mediated cell-cycle arrest in response to genotoxins while loss of HSF1 attenuates apoptosis in response to these agents. To explain these novel properties of HSF1 we show that HSF1 can complex with DNA damage kinases ATR and Chk1 to effect p53 phosphorylation in response to DNA damage. Our data reveal HSF1 as a key transcriptional regulator in response to genotoxic compounds widely used in the clinical setting, and suggest that HSF1 will contribute to the efficacy of these agents

Genetic diversity of Brazilian isolates of feline immunodeficiency virus

We isolated Feline immunodeficiency virus (FIV) from three adult domestic cats, originating from two open shelters in Brazil. Viruses were isolated from PBMC following co-cultivation with the feline T-lymphoblastoid cell line MYA-1. All amplified env gene products were cloned directly into pGL8MYA. The nucleic acid sequences of seven clones were determined and then compared with those of previously described isolates. The sequences of all of the Brazilian virus clones were distinct and phylogenetic analysis revealed that all belong to subtype B. Three variants isolated from one cat and two variants were isolated from each of the two other cats, indicating that intrahost diversity has the potential to pose problems for the treatment and diagnosis of FIV infection

Response to ‘Re: Kakkos et al. Efficacy and Safety of the New Oral Anticoagulants Dabigatran, Rivaroxaban, Apixaban, and Edoxaban in the Treatment and Secondary Prevention of Venous Thromboembolism: A Systematic Review and Meta-analysis of Phase III Trials’

We estimated and compared the risk of clinically identified acquired drug resistance under immediate initiation [the currently recommended antiretroviral therapy (ART) initiation strategy], initiation with CD4 cell count less than 500 cells/μl and initiation with CD4 cell count less than 350 cells/μl. Cohort study based on routinely collected data from the HIV-CAUSAL collaboration. For each individual, baseline was the earliest time when all eligibility criteria (ART-naive, AIDS free, and others) were met after 1999. Acquired drug resistance was defined using the Stanford classification as resistance to any antiretroviral drug that was clinically identified at least 6 months after ART initiation. We used the parametric g-formula to adjust for time-varying (CD4 cell count, HIV RNA, AIDS, ART regimen, and drug resistance testing) and baseline (calendar period, mode of acquisition, sex, age, geographical origin, ethnicity and cohort) characteristics. In 50 981 eligible individuals, 10% had CD4 cell count more than 500 cells/μl at baseline, and 63% initiated ART during follow-up. Of 2672 tests for acquired drug resistance, 794 found resistance. The estimated 7-year risk (95% confidence interval) of acquired drug resistance was 3.2% (2.8,3.5) for immediate initiation, 3.1% (2.7,3.3) for initiation with CD4 cell count less than 500 cells/μl, and 2.8% (2.5,3.0) for initiation with CD4 cell count less than 350 cells/μl. In analyses restricted to individuals with baseline in 2005-2015, the corresponding estimates were 1.9% (1.8, 2.5), 1.9% (1.7, 2.4), and 1.8% (1.7, 2.2). Our findings suggest that the risk of acquired drug resistance is very low, especially in recent calendar periods, and that immediate ART initiation only slightly increases the risk. It is unlikely that drug resistance will jeopardize the proven benefits of immediate ART initiation

A physiological time analysis of the duration of the gonotrophic cycle of Anopheles pseudopunctipennis and its implications for malaria transmission in Bolivia

<p>Abstract</p> <p>Background</p> <p>The length of the gonotrophic cycle varies the vectorial capacity of a mosquito vector and therefore its exact estimation is important in epidemiological modelling. Because the gonotrophic cycle length depends on temperature, its estimation can be satisfactorily computed by means of physiological time analysis.</p> <p>Methods</p> <p>A model of physiological time was developed and calibrated for <it>Anopheles pseudopunctipennis</it>, one of the main malaria vectors in South America, using data from laboratory temperature controlled experiments. The model was validated under varying temperatures and could predict the time elapsed from blood engorgement to oviposition according to the temperature.</p> <p>Results</p> <p>In laboratory experiments, a batch of <it>An. pseudopunctipennis </it>fed at the same time may lay eggs during several consecutive nights (2–3 at high temperature and > 10 at low temperature). The model took into account such pattern and was used to predict the range of the gonotrophic cycle duration of <it>An. pseudopunctipennis </it>in four characteristic sites of Bolivia. It showed that the predicted cycle duration for <it>An. pseudopunctipennis </it>exhibited a seasonal pattern, with higher variances where climatic conditions were less stable. Predicted mean values of the (minimum) duration ranged from 3.3 days up to > 10 days, depending on the season and the geographical location. The analysis of ovaries development stages of field collected biting mosquitoes indicated that the phase 1 of Beklemishev might be of significant duration for <it>An. pseudopunctipennis</it>. The gonotrophic cycle length of <it>An. pseudopunctipennis </it>correlates with malaria transmission patterns observed in Bolivia which depend on locations and seasons.</p> <p>Conclusion</p> <p>A new presentation of cycle length results taking into account the number of ovipositing nights and the proportion of mosquitoes laying eggs is suggested. The present approach using physiological time analysis might serve as an outline to other similar studies and allows the inclusion of temperature effects on the gonotrophic cycle in transmission models. However, to better explore the effects of temperature on malaria transmission, the others parameters of the vectorial capacity should be included in the analysis and modelled accordingly.</p

Alzheimer’s disease genetic risk and cognitive reserve in relationship to long-term cognitive trajectories among cognitively normal individuals

Background: Both Alzheimer’s disease (AD) genetic risk factors and indices of cognitive reserve (CR) influence risk of cognitive decline, but it remains unclear whether they interact. This study examined whether a CR index score modifies the relationship between AD genetic risk factors and long-term cognitive trajectories in a large sample of individuals with normal cognition. Methods: Analyses used data from the Preclinical AD Consortium, including harmonized data from 5 longitudinal cohort studies. Participants were cognitively normal at baseline (M baseline age = 64 years, 59% female) and underwent 10 years of follow-up, on average. AD genetic risk was measured by (i) apolipoprotein-E (APOE) genetic status (APOE-ε2 and APOE-ε4 vs. APOE-ε3; N = 1819) and (ii) AD polygenic risk scores (AD-PRS; N = 1175). A CR index was calculated by combining years of education and literacy scores. Longitudinal cognitive performance was measured by harmonized factor scores for global cognition, episodic memory, and executive function. Results: In mixed-effects models, higher CR index scores were associated with better baseline cognitive performance for all cognitive outcomes. APOE-ε4 genotype and AD-PRS that included the APOE region (AD-PRSAPOE) were associated with declines in all cognitive domains, whereas AD-PRS that excluded the APOE region (AD-PRSw/oAPOE) was associated with declines in executive function and global cognition, but not memory. There were significant 3-way CR index score × APOE-ε4 × time interactions for the global (p = 0.04, effect size = 0.16) and memory scores (p = 0.01, effect size = 0.22), indicating the negative effect of APOE-ε4 genotype on global and episodic memory score change was attenuated among individuals with higher CR index scores. In contrast, levels of CR did not attenuate APOE-ε4-related declines in executive function or declines associated with higher AD-PRS. APOE-ε2 genotype was unrelated to cognition. Conclusions: These results suggest that APOE-ε4 and non-APOE-ε4 AD polygenic risk are independently associated with global cognitive and executive function declines among individuals with normal cognition at baseline, but only APOE-ε4 is associated with declines in episodic memory. Importantly, higher levels of CR may mitigate APOE-ε4-related declines in some cognitive domains. Future research is needed to address study limitations, including generalizability due to cohort demographic characteristics