Regulation of central metabolism genes of Mycobacterium tuberculosis by parallel feed-forward loops controlled by sigma factor E (σ(E))

Cells respond to external stimuli through networks of regulatory interactions. The human pathogen Mycobacterium tuberculosis responds to stress encountered during infection by arresting multiplication and implementing critical metabolic changes that lead to or sustain the nonreplicative state. Much of this differentiation program is recapitulated when M. tuberculosis cultures are subjected to gradual oxygen depletion in vitro. Here we report that hypoxic induction of critical central metabolism genes in the glyoxylate shunt (icl1) and in the methylcitrate cycle (gltA1) involves both global and local regulators. The global regulators are accessory sigma factors σ(B) for icl1 and σ(E) for gltA1. The local regulators are the products of two paralogous genes mapping at positions adjacent to the corresponding effector gene or operon. We call these genes lrpI and lrpG (for local regulatory protein of icl1 and gltA1). We also found that (i) each sigma factor controls the corresponding local regulator, (ii) both global and local regulators are required for effector gene induction, and (iii) the occurrence of sigma factor control of effector gene induction is independent of its control over the corresponding local regulator. Together, these data indicate that induction of icl1 and gltA1 utilizes parallel feed-forward loops with an AND input function. Both feed-forward loops are affected by σ(E), since this sigma factor is part of the gltA1 loop and controls sigB in the icl1 loop. Feed-forward loops may critically contribute to the cellular developmental program associated with M. tuberculosis dormancy.     

The serogroup B meningococcal outer membrane vesicle-based vaccine 4CMenB induces cross-species protection against Neisseria gonorrhoeae

There is a pressing need for a gonorrhea vaccine due to the high disease burden associated with gonococcal infections globally and the rapid evolution of antibiotic resistance in Neisseria gonorrhoeae (Ng). Current gonorrhea vaccine research is in the stages of antigen discovery and the identification of protective immune responses, and no vaccine has been tested in clinical trials in over 30 years. Recently, however, it was reported in a retrospective case-control study that vaccination of humans with a serogroup B Neisseria meningitidis (Nm) outer membrane vesicle (OMV) vaccine (MeNZB) was associated with reduced rates of gonorrhea. Here we directly tested the hypothesis that Nm OMVs induce cross-protection against gonorrhea in a well-characterized female mouse model of Ng genital tract infection. We found that immunization with the licensed Nm OMV-based vaccine 4CMenB (Bexsero) significantly accelerated clearance and reduced the Ng bacterial burden compared to administration of alum or PBS. Serum IgG and vaginal IgA and IgG that cross-reacted with Ng OMVs were induced by 4CMenB vaccination by either the subcutaneous or intraperitoneal routes. Antibodies from vaccinated mice recognized several Ng surface proteins, including PilQ, BamA, MtrE, NHBA (known to be recognized by humans), PorB, and Opa. Immune sera from both mice and humans recognized Ng PilQ and several proteins of similar apparent molecular weight, but MtrE was only recognized by mouse serum. Pooled sera from 4CMenB-immunized mice showed a 4-fold increase in serum bactericidal₅₀ titers against the challenge strain; in contrast, no significant difference in bactericidal activity was detected when sera from 4CMenB-immunized and unimmunized subjects were compared. Our findings directly support epidemiological evidence that Nm OMVs confer cross-species protection against gonorrhea, and implicate several Ng surface antigens as potentially protective targets. Additionally, this study further defines the usefulness of murine infection model as a relevant experimental system for gonorrhea vaccine development.     

Proteomic approach to address low seed germination in <Emphasis Type="Italic">Cyclobalnopsis gilva</Emphasis>

Seeds play essential roles in plant life cycle and germination is a complex process which is associated with different phases of water imbibition. Upon imbibition, seeds begin utilization of storage substances coupled with metabolic activity and biosynthesis of new proteins. Regeneration of organelles and emergence of radicals lead to the establishment of seedlings. All these activities are regulated in coordinated manners. Translation is the requirement of germination of seeds via involvements of several proteins like beta-amylase, starch phosphorylase. Some important proteins involved in seed germination are discussed in this review. In the past decade, several proteomic studies regarding seed germination of various species such as rice, Arabidopsis have been conducted. We face A paucity of proteomic data with respect to woody plants e.g. Fagus, Pheonix etc. With particular reference to Cyclobalnopsis gilva, a woody plant having low seed germination rate, no proteomic studies have been conducted. The review aims to reveal the complex seed germination mechanisms from woody and herbaceous plants that will help in understanding different seed germination phases and the involved proteins in C. gilva.     

Diabetes mellitus and mortality after acute coronary syndrome as a first or recurrent cardiovascular event

Background

Diabetes Mellitus (DM) is associated with adverse cardiovascular prognosis. However, the risk associated with DM may vary between individuals according to their overall cardiovascular risk burden. Therefore, we aimed to determine whether DM is associated with poor outcome in patients presenting with Acute Coronary Syndrome (ACS) according to the index episode being a first or recurrent cardiovascular event.

Methods and Findings

We conducted a retrospective analysis of a prospective cohort study involving 2499 consecutively admitted patients with confirmed ACS in 11 UK hospitals during 2003. Usual care was provided for all participants. Demographic factors, co-morbidity and treatment (during admission and at discharge) factors were recorded. The primary outcome was all cause mortality (median 2 year follow up), compared for cohorts with and without DM according to their prior cardiovascular disease (CVD) disease status. Adjusted analyses were performed with Cox proportional hazards regression analysis. Within the entire cohort, DM was associated with an unadjusted 45% increase in mortality. However, in patients free of a history of CVD, mortality of those with and without DM was similar (18.8% and 19.7% respectively; p = 0.74). In the group with CVD, mortality of patients with DM was significantly higher than those without DM (46.7% and 33.2% respectively; p<0.001). The age and sex adjusted interaction between DM and CVD in predicting mortality was highly significant (p = 0.002) and persisted after accounting for comorbidities and treatment factors (p = 0.006). Of patients free of CVD, DM was associated with smaller elevation of Troponin I (p<0.001). However in patients with pre-existing CVD Troponin I was similar (p = 0.992).

Conclusions

DM is only associated with worse outcome after ACS in patients with a pre-existing history of CVD. Differences in the severity of myocyte necrosis may account for this. Further investigation is required, though our findings suggest that aggressive primary prevention of CVD in patients with DM may have beneficially modified their first presentation with (and mortality after) ACS.     

Cardioprotective Signature of Short-Term Caloric Restriction

Objective

To understand the molecular pathways underlying the cardiac preconditioning effect of short-term caloric restriction (CR).

Background

Lifelong CR has been suggested to reduce the incidence of cardiovascular disease through a variety of mechanisms. However, prolonged adherence to a CR life-style is difficult. Here we reveal the pathways that are modulated by short-term CR, which are associated with protection of the mouse heart from ischemia.

Methods

Male 10-12 wk old C57bl/6 mice were randomly assigned to an ad libitum (AL) diet with free access to regular chow, or CR, receiving 30% less food for 7 days (d), prior to myocardial infarction (MI) via permanent coronary ligation. At d8, the left ventricles (LV) of AL and CR mice were collected for Western blot, mRNA and microRNA (miR) analyses to identify cardioprotective gene expression signatures. In separate groups, infarct size, cardiac hemodynamics and protein abundance of caspase 3 was measured at d2 post-MI.

Results

This short-term model of CR was associated with cardio-protection, as evidenced by decreased infarct size (18.5±2.4% vs. 26.6±1.7%, N=10/group; P=0.01). mRNA and miR profiles pre-MI (N=5/group) identified genes modulated by short-term CR to be associated with circadian clock, oxidative stress, immune function, apoptosis, metabolism, angiogenesis, cytoskeleton and extracellular matrix (ECM). Western blots pre-MI revealed CR-associated increases in phosphorylated Akt and GSK3ß, reduced levels of phosphorylated AMPK and mitochondrial related proteins PGC-1α, cytochrome C and cyclooxygenase (COX) IV, with no differences in the levels of phosphorylated eNOS or MAPK (ERK1/2; p38). CR regimen was also associated with reduced protein abundance of cleaved caspase 3 in the infarcted heart and improved cardiac function.     

Screening of different contaminated environments for polyhydroxyalkanoates-producing bacterial strains

Total sixteen bacterial strains were isolated and purified from the samples collected from sugarcane molasses soil, sewage water and long-chain-hydrocarbon-contaminated area of the Punjab University, Lahore, Pakistan. Tolerance to different antibiotics was studied and strains showed multiple antibiotic resistance. All strains were characterized for Gram stain, biochemical reactions and polyhydroxyalkanoate (PHA) production. Total fourteen strains were Gram negative and two were Gram positive, while biochemically nine PHA producers showed affiliation to Pseudomonas, Enterobacter, Citrobacter, Bacillus and Escherichia. Screening for PHA production was done by Sudan black staining and nine out of sixteen strains exhibited PHA producing ability. PHA production was optimized for different growth parameters, like nitrogen concentration, pH and temperature. PHA extraction was done by solvent extraction method. Bacterial strains US1 and M1 accumulated up to 30% PHA of their cell dry weight on PHA extraction by solvent extraction method. Bacterial strain US1 was identified by 16S rRNA gene analysis as P. aeruginosa (DQ455691). PHA production was confirmed by PCR amplification of 500 bp fragment from PHA polymerase (Pha C) gene; five strains from nine PHA producers gave positive results on PCR. Pha C gene fragment of US1 was sequenced and submitted to Gene Bank under the accession number DQ455690. The amino acid sequence showed homology using the protein BLAST at 129–132 sites with different PHA synthases of the Pseudomonas sp.     

A review on emerging persistent organic pollutants: Current scenario in Pakistan

During the last few years, a new drift on screening of persistent organic pollutants (POPs) present in the environment of Pakistan has been observed. However, across the globe a number of reports have been devoted to the screening levels, distribution, and risk assessment and on the emission of POPs. In the case of Pakistan, the knowledge achieved and understanding of POPs contamination in the environmental compartments are still limited. Recently published literature has been a key to explore the mystery of new emerging POPs from the environment of the country. In this review, an effort was made to summarize the results of recently published reports on POPs (PCNs, PBDEs, DPs, and PCBs) from biotic and abiotic environments of Pakistan. This review also presents the available data published to date for organochlorines. The results of previously reported studies reflected that newly emerging POPs were influenced by the industrial and urban fractions and were in line with the distribution pattern of other regions of the world. These results revealed that urgent attention must be paid to these new emerging POPs, as they are reported to be present in considerable concentrations. Such detected concentrations of these banned pollutants should be checked/screened by scientific authorities to avoid adverse health risks to humans and animals.     

Only pollinator fig wasps have males that collaborate to release their females from figs of an Asian fig tree

Male insects rarely collaborate with each other, but pollinator fig wasps (Hymenoptera: Agaonidae) are said to be an exception. Immature fig wasps feed on galled ovules located inside figs, the inflorescences of Ficus species (Moraceae). After mating, adult pollinator males chew communal exit-holes that allow mated females (which are often also their siblings) to escape. Figs also support non-pollinating fig wasps (NPFWs), some of which produce exit-holes independently. We determined whether collaboration between pollinator males (Kradibia tentacularis from Ficus montana) was necessary for the release of their females, and used the relationship between male numbers and likelihood of success to measure the extent of cooperation during exit-hole production. These attributes were then compared with those of an NPFW (Sycoscapter sp.) from the same host plant. Pollinators were more abundant than NPFW, but their more female-biased sex ratio meant male pollinator densities were only slightly higher. Individual males of both species could produce an exit-hole. Single males of the NPFW were just as successful as single male pollinators, but only male pollinators cooperated effectively, becoming more successful as their numbers increased. The lack of cooperation among NPFW may be linked to their earlier period of intense inter-male aggression.