Foliar treatment of potassium nitrate modulates the fermentative and sucrose metabolizing pathways in contrasting maize genotypes under water logging stress

Physiology and Molecular Biology of Plants - The effect of potassium nitrate on the status of fermentative and sucrose metabolizing pathways was studied in two maize (Zea mays L.) genotypes, viz.,...     

Mycobacterium tuberculosis carbon and nitrogen metabolic fluxes

Mycobacterium tuberculosis (Mtb) is one of the most formidable pathogens causing tuberculosis (TB), a devastating infectious disease responsible for the highest human mortality and morbidity. The emergence of drug-resistant strains of the pathogen has increased the burden of TB tremendously and new therapeutics to overcome the problem of drug resistance are urgently needed. Metabolism of Mtb and its interactions with the host is important for its survival and virulence; this is an important topic of research where there is growing interest in developing new therapies and drugs that target these interactions and metabolism of the pathogen during infection. Mtb adapts its metabolism in its intracellular niche and acquires multiple nutrient sources from the host cell. Carbon metabolic pathways and fluxes of Mtb has been extensively researched for over a decade and is well-defined. Recently, there has been investigations and efforts to measure metabolism of nitrogen, which is another important nutrient for Mtb during infection. This review discusses our current understanding of the central carbon and nitrogen metabolism, and metabolic fluxes that are important for the survival of the TB pathogen.     

Video Capsule Endoscopy in Patients with Chronic Abdominal Pain with or without Associated Symptoms: A Retrospective Study

Background

Chronic abdominal pain (CAP) is a common indication for gastroenterology referrals. More insidious causes of CAP isolated to the small bowel, such as malignancies and Crohn’s disease, are rising in incidence and causing more gastroenterologists to evaluate their patients with video capsule endoscopy (VCE). However, the role of VCE in patients with CAP is still unclear.

Aims

We assessed the efficacy of VCE in patients with CAP and whether it led to findings that contributed to disease management and meaningful interventions.

Methods

This retrospective study evaluated 607 capsule endoscopy studies at an open referral endoscopy unit. Ninety of the studies were for CAP. These studies were compared to those performed for other indications to compare diagnostic yield. In addition, we investigated whether VCE led to an intervention that improved clinical outcomes.

Results

Overall, the number of abnormal findings in CAP patients was significantly lower than VCE performed for other indications (24.4% vs 39.0%, respectively p = 0.009). When patients with CAP presented with other pertinent clinical findings (e.g. nausea, weight loss, anemia, history of in inflammatory bowel disease, etc.), the likelihood of an abnormal finding increased to a level that was not different from those who received VCE for other indications (27.1%, p = 0.10). The findings from VCE lead to changed management and improved outcomes in 16.2% of CAP patients with associated symptoms. However, the subgroup that benefited the most were those who had a prior history of Crohn’s disease. Patients with CAP who did not have any associated symptoms continued to have a significantly lower abnormal finding rate compared to those who received VCE for other indications (19.4%, p = 0.03) and VCE rarely led to a change in management that would improve outcomes (5.6%).

Conclusions

VCE for CAP has a lower rate of abnormal findings than other indications. However, VCE is a useful diagnostic tool that can help provide a possible etiology of CAP in patients with associated symptoms. However, a change in management from VCE is likely to be limited to those with a history of Crohn’s disease.     

Conservation of Dynamics Associated with Biological Function in an Enzyme Superfamily

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Exogenous application of calcium chloride in wheat genotypes alleviates negative effect of drought stress by modulating antioxidant machinery and enhanced osmolyte accumulation

Plants use various mechanisms to cope with drought constraints at morphological, physiological, and biochemical level by means of different adaptive mechanisms. All organisms use a network of signal transduction pathways to control their metabolism and to adapt to the environment. Among these pathways, calcium (Ca²⁺) ions play an important role as a universal second messenger. Calcium has unique properties and universal ability to transmit diverse signals that trigger primary physiological actions in the cell in response to hormones, pathogens, and stress factors. Calcium plays a fundamental role in regulating the polar growth of cells and tissues and participates in plant adaptation to various stress factors. This study was conducted to examine the role of Ca²⁺ in ameliorating the adverse effect of drought stress responses in two contrasting wheat genotypes, HD 2733 (drought sensitive) and HD 2987 (drought tolerant), differing in their drought tolerance. The plants were treated with mannitol or Hoagland solution and then supplemented with CaCl₂ (10 mM). Measurements of seed germination, shoot growth, and chlorophyll content showed that calcium treatment increased all these factors in tolerant genotype (HD 2987) under induced stress condition. Drought stress reduced relative water content, osmolyte, and soluble sugar accumulation in both the genotypes, but CaCl₂ supplementation increased all the components under stress condition in HD 2987 as compared to HD 2733. The oxidative damage caused by induced stress was lower in HD 2987 compared to HD 2733 genotypes as assessed by their higher photosynthetic capacity and lower electrolyte leakage, malondialdehyde (MDA) content as well as H₂O₂ accumulation. Less accumulation of superoxide and H₂O₂ was also observed in HD 2987 genotype after CaCl₂ supplementation combined with mannitol treatment. In addition, the enhanced accumulation of calcium in the HD 2987 genotype is correlated with the higher activities of antioxidant enzymes than HD 2733 genotype under similar stress conditions. Our findings provide evidence of the protective role of exogenous calcium in conferring better tolerance against mannitol-induced drought stress in wheat genotypes, which could be useful as genetic stock to develop wheat tolerant varieties in breeding programs.     

A novel cytostatic form of autophagy in sensitization of non-small cell lung cancer cells to radiation by vitamin D and the vitamin D analog,EB 1089

The standard of care for unresectable lung cancer is chemoradiation. However, therapeutic options are limited and patients are rarely cured. We have previously shown that vitamin D and vitamin D analogs such as EB 1089 can enhance the response to radiation in breast cancer through the promotion of a cytotoxic form of autophagy. In A549 and H460 non-small cell lung cancer (NSCLC) cells, 1,25-D₃ (the hormonally active form of vitamin D) and EB 1089 prolonged the growth arrest induced by radiation alone and suppressed proliferative recovery, which translated to a significant reduction in clonogenic survival. In H838 or H358 NSCLC cells, which lack VDR/vitamin D receptor or functional TP53, respectively, 1,25-D₃ failed to modify the extent of radiation-induced growth arrest or suppress proliferative recovery post-irradiation. Sensitization to radiation in H1299 NSCLC cells was evident only when TP53 was induced in otherwise tp53-null H1299 NSCLC cells. Sensitization was not associated with increased DNA damage, decreased DNA repair or an increase in apoptosis, necrosis, or senescence. Instead sensitization appeared to be a consequence of the conversion of the cytoprotective autophagy induced by radiation alone to a novel cytostatic form of autophagy by the combination of 1,25-D₃ or EB 1089 with radiation. While both pharmacological and genetic suppression of autophagy or inhibition of AMPK phosphorylation sensitized the NSCLC cells to radiation alone, inhibition of the cytostatic autophagy induced by the combination treatment reversed sensitization. Evidence for selectivity was provided by lack of radiosensitization in normal human bronchial cells and cardiomyocytes. Taken together, these studies have identified a unique cytostatic function of autophagy that appears to be mediated by VDR, TP53, and possibly AMPK in the promotion of an enhanced response to radiation by 1,25-D₃ and EB 1089 in NSCLC.