Transposon Tn5281 is the main distributor of the aminoglycoside modifying enzyme gene among isolates of Enterococcus faecalis in Tehran hospitals

Infections with high levels of gentamicin-resistant (HLGR) isolates of Enterococcus faecalis are common in Tehran hospitals. Genes encoding such resistance are transmissible by conjugation at high frequency. The purpose of this study was to determine the existence of Tn5281 and its flanking aminoglycoside modifying enzyme gene aac(6')-aph(2") among 102 HLGR isolates of E. faecalis cultured from patients at three hospitals in Tehran, Iran. These isolates were detected by disks containing 120 microg of gentamicin and made 65% of all E. faecalis during the study period. DNA was extracted from HLGR isolates and subjected to PCR assays targeting aac(6')-aph(2") and conjugative transposon Tn5281. The amplified aac(6')-aph(2") gene was labeled with digoxigenin and probed with Tn5281 amplicons in dot blot hybridization assays. The aac(6')-aph(2") gene was detected in 91%-92% (n = 93) of the HLGR isolates. All isolates containing aac(6')-aph(2") were positive in long-PCR targeting Tn5281 and the probe hybridized with Tn5281 amplicons. The number of HLGR isolates of E. faecalis has increased considerably in Tehran hospitals. Tn5281 is the main cause of transmission of aac(6')-aph(2") to different isolates of E. faecalis in the hospitals studied.     

The influence of cardiovascular risk factors on bone marrow mesenchymal stromal cell fitness

Background aimsIn the past, cell transplantation strategies for the treatment of heart failure have shown promising results in experimental and clinical studies. Bone marrow (BM)-derived stem cells represent the most frequently used cell population. Within this heterogeneous cell population, mesenchymal stromal cells (MSC) have been identified to induce therapeutic effects, mainly through paracrine mechanisms. Because of their low frequency in native tissues, in vitro cell culture expansion is mandatory prior to transplantation. We sought to identify patient-specific cardiovascular risk factors influencing the proliferative potential of MSC.MethodsBM aspirates from 51 patients undergoing elective cardiac surgery were analyzed for MSC frequency and cell culture expansion potential. Fibroblastic colony-forming units (CFU-F) were quantified for culture conditions applying autologous (AS) or fetal bovine serum (FBS) and different basic media. Univariate and multivariate analyzes were performed in order to determine the impact of patient-specific factors on CFU-F numbers.ResultsExpanded MSC showed a specific immune phenotype and displayed adipogenic, chondrogeneic and osteogeneic differentiation potential. CFU-F numbers did not differ under AS or FBS supplementation. Elevated numbers of mononuclear cells, diabetes mellitus, steroid treatment, chronic obstructive pulmonary disease, renal failure, high euroSCORE and impaired left ventricular function were significant determinants for higher CFU-F numbers.ConclusionsThe impact of specific cardiovascular risk factors on MSC fitness could be determined. These results may help to establish patient profiling in order to identify patients suitable for autologous MSC transplantation, and might lead to the identification of disease-related mechanisms of stem cell activation.     

Activation of rat adipocyte plasma membrane adenylate cyclase by sodium azide

The adenylate cyclase of rat adipocyte plasma membrane is stimulated by sodium azide with a half maximal activation of 100–150% occuring at 50 mM NaN₃. Studies of the effects of azide and fluoride indicate different mechanisms of stimulation of the enzyme by these ions. Comparable stimulation of the activity is obtained by 100 mM NaN₃ or 10 mM NaF but unlike azide, higher concentrations of fluoride cause inhibition of the enzyme. Fluoride activated adenylate cyclase is further stimulated by azide. Epinephrine stimulation of the enzyme is absent in the presence of fluoride but the hormone enhances the activity in the presence of azide. Reversal of the inhibitory action of GTP on adenylate cyclase by epinephrine is demonstrated even in the presence of azide but not in the presence of fluoride.     

Derepressed leucine transport activity in Escherichia coli

Transport activity and synthesis of binding protein for the amino acids leucine, isoleucine and valine in E. coli are coordinately controlled by the level of leucine in the growth medium. Spontaneous mutants (dlu) which can utilize D-leucine as a source of L-leucine show derepressed transport activity for the three-branched chain amino acids. The increased transport activity is a result of an increase in the binding protein for these amino acids. Azaleucine-resistant mutants have been isolated which have a defect in leucine transport but normal levels of the binding protein for leucine.     

Focus: Vaccines: Sufficient Sleep,Time of Vaccination,and Vaccine Efficacy: A Systematic Review of the Current Evidence and a Proposal for COVID-19 Vaccination

Introduction: The emergence of the novel Coronavirus Disease 2019 (COVID-19) sparked an unprecedented effort to develop effective vaccines against the disease. Some factors may boost the vaccine efficacy, including sufficient sleep and morning vaccination. We aimed to conduct a rapid systematic review to summarize data regarding the association between sleep and time of vaccination with immunity after vaccination. Materials and Methods: The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol, and three databases (PubMed, Web of Science, and Scopus) were searched up to March 12, 2022. Results: Eight studies were included regarding the sleep and immune response after vaccination, of them, five studies were on influenza, two studies on hepatitis A (HAV), and one study on hepatitis B. Accordingly, six out of eight studies found a positive correlation between sleep and immune response after vaccination. Regarding the time of vaccination, seven studies were eligible to be included (two studies on influenza, one study on HAV and influenza, one study on BCG, one study on hexavalent vaccine, and two studies on SARS-CoV-2 vaccine). Among them, four out of seven studies (including a study on SARS-CoV-2 inactivated vaccine) reported the priorities of morning versus afternoon vaccination regarding antibody production and immune response after vaccination. Conclusion: Taken together, cumulative evidence suggests that sufficient sleep and vaccination in the morning could enhance the immune response after vaccination. Hence, modulating the time of vaccination and sufficient sleep could a be simple and applicable strategy for increasing vaccine efficacy. Future studies could be performed with SARS-CoV-2 vaccines to investigate the effects of time of vaccination and sufficient sleep on COVID-19 vaccine efficacy.     

Does the intensive grazing and aridity change the relations between the dominant shrub Artemisia kopetdaghensis and plants under its canopies?

The interspecific plant interactions along grazing and aridity stress gradients represent a major research issue in plant ecology. However, the combined effects of these two factors on plant–plant interactions have been poorly studied in the northeast of Iran. To fill this knowledge gap, 144 plots were established in 12 study sites with different grazing intensities (high vs. low) and climatic characteristics (arid vs. semiarid) in northeastern Iran. A dominant shrub, Artemisia kopetdaghensis, was selected as the model species. Further, we studied changes in plant life strategies along the combined grazing and aridity stress gradients. In this study, we used relative interaction indices calculated for species richness, Shannon diversity, and species cover to determine plant–plant interactions using linear mixed‐effect models (LMM). The indicator species analysis was used to identify the indicator species for the undercanopy of shrub and for the adjacent open areas. The combined effects of grazing and aridity affected the plant–plant interactions and plant life strategies (CSR) of indicator species. A. kopetdaghensis showed the highest facilitation effect under high stress conditions (high grazing, high aridity), which turned into competition under the low stress conditions (low grazing, low aridity). In the arid region, the canopy of the shrub protected ruderals, annual forbs, and grasses in both high and low grazing intensities. In the semiarid region and high grazing intensity (low aridity/high grazing), the shrubs protected mostly perennial forbs with C‐strategy. Our findings highlight the importance of context‐dependent shrub management to restore the vegetation damaged by the intensive grazing.     

Pregnant women with COVID-19: the placental involvement and consequences

Journal of Molecular Histology - SARS-CoV-2, the leading cause of COVID-19 pandemic, was detected for the first time in Wuhan. In this study, we investigated the potential undesirable maternal and...