Mycobacterium tuberculosis lysine-ɛ-aminotransferase a potential target in dormancy: Benzothiazole based inhibitors

MTB lysine-?-aminotransferase (LAT) was found to play a crucial role in persistence and antibiotic tolerance. LAT serves as a potential target in the management of latent tuberculosis. In present work we attempted to derivatize the benzothiazole lead identified through high throughput virtual screening of Birla Institute of Technology and Science in house database. For Structure activity relationship purpose 22 derivatives were synthesized and characterized. Among synthesized compounds, eight compounds were found to be more efficacious in terms of LAT inhibition when compared to lead compound (IC₅₀ 10.38 ± 1.21 µM). Compound 22 exhibits bactericidal action against nutrient starved Mycobacterium tuberculosis (MTB). It also exhibits significant activity in nutrient starvation model (2.9 log folds) and biofilm model (2.3 log folds).     

C-Phycocyanin Modulates Selenite-Induced Cataractogenesis in Rats

The present investigation is aimed to evaluate the anticataractogenic potential of C-phycocyanin (C-PC), extracted and purified from Spirulina platensis. Enucleated rat lenses were maintained in vitro in Dulbecco’s modified Eagle medium (DMEM). Group I contained DMEM, Group II and Group III contained 100 μM of sodium selenite, Group III was subdivided into three viz IIIa, IIIb, IIIc supplemented with 100, 150, 200 μg of C-PC respectively. In the in vivo study, on tenth day post partum: Group I rat pups received an intraperitoneal injection of saline, Group II, IIIa, IIIb, and IIIc rat pups received a subcutaneous injection of sodium selenite (19 μmol/kg bodyweight) Group IIIa, IIIb, IIIc also received an intraperitoneal injection of 100, 150, 200 mg/kg body weight of C-PC, respectively, from postpartum days?9–14. On termination of the experiment, the lenses from both in vitro and in vivo studies were subjected to morphological examination and subsequently processed to estimate the activities of antioxidant enzymes namely superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, levels of reduced glutathione and lipid peroxidation products. Sodium selenite-exposed, C-PC-treated rat lenses (Group IIIc), showed significant restoration of antioxidant enzyme activity (p?<?0.05) when compared to their counterpart Group II. Group IIIc conserved the levels of GSH and lipid peroxidation products at near to normal levels as compared with Group II. Results conclude the possible role of C-PC in modulating the antioxidant enzyme status, thereby retarding sodium selenite-induced cataract incidence both in vitro and in vivo.     

Drosophila Sirtuin 6 mediates developmental diet‐dependent programming of adult physiology and survival

Organisms in the wild experience unpredictable and diverse food availability throughout their lifespan. Over‐/under‐nutrition during development and in adulthood is known to dictate organismal survival and fitness. Studies using model systems have also established long‐term effects of developmental dietary alterations on life‐history traits. However, the underlining genetic/molecular factors, which differentially couple nutrient inputs during development with fitness later in life are far less understood. Using Drosophila and loss/gain of function perturbations, our serendipitous findings demonstrate an essential role of Sirtuin 6 in regulating larval developmental kinetics, in a nutrient‐dependent manner. The absence of Sirt6 affected ecdysone and insulin signalling and led to accelerated larval development. Moreover, varying dietary glucose and yeast during larval stages resulted in enhanced susceptibility to metabolic and oxidative stress in adults. We also demonstrate an evolutionarily conserved role for Sirt6 in regulating physiological homeostasis, physical activity and organismal lifespan, known only in mammals until now. Our results highlight gene‐diet interactions that dictate thresholding of nutrient inputs and physiological plasticity, operative across development and adulthood. In summary, besides showing its role in invertebrate ageing, our study also identifies Sirt6 as a key factor that programs macronutrient‐dependent life‐history traits.     

Involvement of protein kinase A in the phosphorylation of spermatidal protein TP2 and its effect on DNA condensation.

Rat spermatidal protein TP2 is rich in serine residues and has several potential sites for phosphorylation by different protein kinases. Recombinant TP2 is phosphorylated upon incubation in vitro with salt extract of testicular sonication resistant nuclei (SRN) (representing elongating and elongated spermatids). The major phosphorylation sites were localized to the C-terminal, V8 protease-derived, fragment (residues 87-114). Phosphorylation experiments with the wild type and different site-specific mutants of TP2 revealed that serine 109 and threonine 101 are the phosphorylation sites. Phosphorylation of the C-terminal fragment of TP2 was also demonstrated in vivo. Phosphorylation was not stimulated by either protein kinase C activators or cGMP but was inhibited by protein kinase A inhibitor (PKI) peptide, showing the involvement of protein kinase A in the phosphorylation of TP2. Phosphorylation of TP2 greatly reduced its DNA condensation property. TP2 when complexed with DNA was not a good substrate for phosphorylation by PKA. Dephosphorylation of the DNA-TP2 complex by calf intestinal alkaline phosphatase restored the DNA condensation property to a level equivalent to that observed with TP2. The physiological significance of the phosphorylation-dephosphorylation cycle is discussed with reference to the two-domain model of TP2.     

Synthesis of highly potent novel anti-tubercular isoniazid analogues with preliminary pharmacokinetic evaluation

Thirty two novel isoniazid analogues were prepared by one-pot three component condensations of isoniazid (INH), 3-mercaptopropionic acid and various aryl/heteroaryl aldehydes. The synthesized compounds were evaluated for their anti-TB activity against Mycobacterium tuberculosis H37Rv (MTB) and cytotoxicity. Among the compounds, compound N-(2-(4-(benzyloxy) phenyl)-4-oxo-1,3-thiazinan-3-yl) isonicotinamide (17) inhibited MTB with MIC of 0.12 μM and was three times more potent than INH. The main pharmacokinetic parameters after intravenous administration (10 mg/kg body weight) in male Wistar rats viz. t_½, K_el, mean plasma clearance and mean volume of distribution were found to be 1.14 ± 0.20 h, 0.62 ± 0.10 h^?1, 22.48 ± 0.16 mL/kg/min and 1.99 ± 0.49 L, respectively. The systemic absorption was slow after oral administration (50 mg/kg body weight). The peak plasma concentration was found to be 1.31 ± 0.06 μg/mL attained in 3 h. The bioavailability was found to be 16.7%.     

Mitochondrial Alterations and Oxidative Stress in an Acute Transient Mouse Model of Muscle Degeneration: IMPLICATIONS FOR MUSCULAR DYSTROPHY AND RELATED MUSCLE PATHOLOGIES*

Muscular dystrophies (MDs) and inflammatory myopathies (IMs) are debilitating skeletal muscle disorders characterized by common pathological events including myodegeneration and inflammation. However, an experimental model representing both muscle pathologies and displaying most of the distinctive markers has not been characterized. We investigated the cardiotoxin (CTX)-mediated transient acute mouse model of muscle degeneration and compared the cardinal features with human MDs and IMs. The CTX model displayed degeneration, apoptosis, inflammation, loss of sarcolemmal complexes, sarcolemmal disruption, and ultrastructural changes characteristic of human MDs and IMs. Cell death caused by CTX involved calcium influx and mitochondrial damage both in murine C2C12 muscle cells and in mice. Mitochondrial proteomic analysis at the initial phase of degeneration in the model detected lowered expression of 80 mitochondrial proteins including subunits of respiratory complexes, ATP machinery, fatty acid metabolism, and Krebs cycle, which further decreased in expression during the peak degenerative phase. The mass spectrometry (MS) data were supported by enzyme assays, Western blot, and histochemistry. The CTX model also displayed markers of oxidative stress and a lowered glutathione reduced/oxidized ratio (GSH/GSSG) similar to MDs, human myopathies, and neurogenic atrophies. MS analysis identified 6 unique oxidized proteins from Duchenne muscular dystrophy samples (n = 6) (versus controls; n = 6), including two mitochondrial proteins. Interestingly, these mitochondrial proteins were down-regulated in the CTX model thereby linking oxidative stress and mitochondrial dysfunction. We conclude that mitochondrial alterations and oxidative damage significantly contribute to CTX-mediated muscle pathology with implications for human muscle diseases.     

A cross-sectional study of the microeconomic impact of cardiovascular disease hospitalization in four low- and middle-income countries

Objective

To estimate individual and household economic impact of cardiovascular disease (CVD) in selected low- and middle-income countries (LMIC).

Background

Empirical evidence on the microeconomic consequences of CVD in LMIC is scarce.

Methods and Findings

We surveyed 1,657 recently hospitalized CVD patients (66% male; mean age 55.8 years) from Argentina, China, India, and Tanzania to evaluate the microeconomic and functional/productivity impact of CVD hospitalization. Respondents were stratified into three income groups. Median out-of-pocket expenditures for CVD treatment over 15 month follow-up ranged from 354 international dollars (2007 INT$, Tanzania, low-income) to INT$2,917 (India, high-income). Catastrophic health spending (CHS) was present in >50% of respondents in China, India, and Tanzania. Distress financing (DF) and lost income were more common in low-income respondents. After adjustment, lack of health insurance was associated with CHS in Argentina (OR 4.73 [2.56, 8.76], India (OR 3.93 [2.23, 6.90], and Tanzania (OR 3.68 [1.86, 7.26] with a marginal association in China (OR 2.05 [0.82, 5.11]). These economic effects were accompanied by substantial decreases in individual functional health and productivity.

Conclusions

Individuals in selected LMIC bear significant financial burdens following CVD hospitalization, yet with substantial variation across and within countries. Lack of insurance may drive much of the financial stress of CVD in LMIC patients and their families.     

Micro-cloning of an economic rattan palm Calamus thwaitesii for eco-restoration programme

Axillary shoots were induced from shoot tip of Calamus thwaitesii suckers on Murashige and Skoog medium supplemented with 0.4 mg/L N6-benzylaminopurine and 0.1 mg/L each of thidiazuron and α-naphthaleneacetic acid (NAA). The shoots initiated were subcultured to fresh media of the same composition for shoot multiplication and multiplied shoots were transferred to half strength MS hormone-free media for shoot elongation. The elongated shoots (～5cm) were then re-cultured to the media supplemented with 3.0 mg/L indole-3-butyric acid/4.0 mg/L NAA to raise plantlets which were subsequently analysed for genetic fidelity using inter simple sequence repeat markers. Out of 183 bands scored, 178 bands were monomorphic indicating 97.2% similarity. The observed low level of polymorphism between genotypes supports genetic consistency of these micro-clones that are likely to be genetically true to their parental origin. The clones thus obtained were hardened in the specially fabricated mist house at 29 ±2°C and 80±5% relative humidity for 3 months followed by shifting to green house for another 3 months of nursery establishment. The established plants when reintroduced to the selected forest segments of the Western Ghats, Kerala (India) showed 79.3% survival rate after 2 years of field transfer. The viable and highly reproducible in vitro cloning protocol demonstrated here for the first time can be used for the production of elite female clones for aforestation activities and sustained delivery of high quality raw materials to cane processing units for strengthening cane industry.