Comparative palynology and wood anatomy of <Emphasis Type="Italic">Taxodium distichum</Emphasis> (L.) Rich. and <Emphasis Type="Italic">Taxodium mucronatum</Emphasis> Ten.

A comparative study of Taxodium distichum (L.) Rich. and Taxodium mucronatum Ten. was carried out on the basis of pollen morphology and wood anatomy by light and scanning electron microscopy. We describe a detailed analysis of the anatomical characteristics of the wood, including the tracheids, ray parenchyma, axial parenchyma and number of cross-field pits. Palynological characters were also studied to reveal the shape, size and ultrastructure of the pollen grains. These studies give taxonomic support for the recognition of T. distichum and T. mucronatum as two different species.     

Mechanism of glucose-6-phosphate dehydrogenase-mediated regulation of coronary artery contractility

We previously identified glucose-6-phosphate dehydrogenase (G6PD) as a regulator of vascular smooth muscle contraction. In this study, we tested our hypothesis that G6PD activated by KCl via a phosphatase and tensin homologue deleted on chromosome 10 (PTEN)-protein kinase C (PKC) pathway increases vascular smooth muscle contraction and that inhibition of G6PD relaxes smooth muscle by decreasing intracellular Ca(2+) ([Ca(2+)](i)) and Ca(2+) sensitivity to the myofilament. Here we show that G6PD is activated by membrane depolarization via PKC and PTEN pathway and that G6PD inhibition decreases intracellular free calcium ([Ca(2+)](i)) in vascular smooth muscle cells and thus arterial contractility. In bovine coronary artery (CA), KCl (30 mmol/l) increased PKC activity and doubled G6PD V(max) without affecting K(m). KCl-induced PKC and G6PD activation was inhibited by bisperoxo(pyridine-2-carboxyl)oxovanadate (Bpv; 10 μmol/l), a PTEN inhibitor, which also inhibited (P < 0.05) KCl-induced CA contraction. The G6PD blockers 6-aminonicotinamide (6AN; 1 mmol/l) and epiandrosterone (EPI; 100 μmol/l) inhibited KCl-induced increases in G6PD activity, [Ca(2+)](i), Ca(2+)-dependent myosin light chain (MLC) phosphorylation, and contraction. Relaxation of precontracted CA by 6AN and EPI was not blocked by calnoxin (10 μmol/l), a plasma membrane Ca(2+) ATPase inhibitor or by lowering extracellular Na(+), which inhibits the Na(+)/Ca(2+) exchanger (NCX), but cyclopiazonic acid (200 μmol/l), a sarcoplasmic reticulum Ca(2+) ATPase inhibitor, reduced (P < 0.05) 6AN- and EPI-induced relaxation. 6AN also attenuated phosphorylation of myosin phosphatase target subunit 1 (MYPT1) at Ser855, a site phosphorylated by Rho kinase, inhibition of which reduced (P < 0.05) KCl-induced CA contraction and 6AN-induced relaxation. By contrast, 6AN increased (P < 0.05) vasodilator-stimulated phosphoprotein (VASP) phosphorylation at Ser239, indicating that inhibition of G6PD increases PKA or PKG activity. Inhibition of PKG by RT-8-Br-PET-cGMPs (100 nmol/l) diminished 6AN-evoked VASP phosphorylation (P < 0.05), but RT-8-Br-PET-cGMPs increased 6AN-induced relaxation. These findings suggest G6PD inhibition relaxes CA by decreasing Ca(2+) influx, increasing Ca(2+) sequestration, and inhibiting Rho kinase but not by increasing Ca(2+) extrusion or activating PKG.     

Cholesterol organization in membranes at low concentrations: effects of curvature stress and membrane thickness

Cholesterol is often found distributed nonrandomly in domains in biological and model membranes and has been reported to be distributed heterogeneously among various intracellular membranes. Although a large body of literature exists on the organization of cholesterol in plasma membranes or membranes with high cholesterol content, very little is known about organization of cholesterol in membranes containing low amounts of cholesterol. Using a fluorescent cholesterol analog (25-[N-[(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-methyl]amino]-27-norcholesterol, or NBD-cholesterol), we have previously shown that cholesterol may exhibit local organization even at very low concentrations in membranes, which could possibly be attributable to transbilayer tail-to-tail dimers. This is supported by similar observations reported by other groups using cholesterol or dehydroergosterol, a naturally occurring fluorescent cholesterol analog which closely mimics cholesterol. In this paper, we have tested the basic features of cholesterol organization in membranes at low concentrations using spectral features of dehydroergosterol. More importantly, we have investigated the role of membrane surface curvature and thickness on transbilayer dimer arrangement of cholesterol using NBD-cholesterol. We find that dimerization is not favored in membranes with high curvature. However, cholesterol dimers are observed again if the curvature stress is relieved. Further, we have monitored the effect of membrane thickness on the dimerization process. Our results show that the dimerization process is stringently controlled by a narrow window of membrane thickness. Interestingly, this type of local organization of NBD-cholesterol at low concentrations is also observed in sphingomyelin-containing membranes. These results could be significant in membranes that have very low cholesterol content, such as the endoplasmic reticulum and the inner mitochondrial membrane, and in trafficking and sorting of cellular cholesterol.     

A systematic review and integrative approach to decode the common molecular link between levodopa response and Parkinson’s disease

Background

PD is a progressive neurodegenerative disorder commonly treated by levodopa. The findings from genetic studies on adverse effects (ADRs) and levodopa efficacy are mostly inconclusive. Here, we aim to identify predictive genetic biomarkers for levodopa response (LR) and determine common molecular link with disease susceptibility. A systematic review for LR was conducted for ADR, and drug efficacy, independently. All included articles were assessed for methodological quality on 14 parameters. GWAS of PD were also reviewed. Protein-protein interaction (PPI) analysis using STRING and functional enrichment using WebGestalt was performed to explore the common link between LR and PD.

Results

From 37 candidate studies on levodopa toxicity, 18 genes were found associated, of which, CA_n STR 13, 14 (DRD2) was most significantly associated with dyskinesia, followed by rs1801133 (MTHFR) with hyper-homocysteinemia, and rs474559 (HOMER1) with hallucination. Similarly, 8 studies on efficacy resulted in 4 genes in which rs28363170, rs3836790 (SLC6A3) and rs4680 (COMT), were significant. To establish the molecular connection between LR with PD, we identified 35 genes significantly associated with PD. With 19 proteins associated with LR and 35 with PD, two independent PPI networks were constructed. Among the 67 nodes (263 edges) in LR, and 62 nodes (190 edges) in PD pathophysiology, UBC, SNCA, FYN, SRC, CAMK2A, and SLC6A3 were identified as common potential candidates.

Conclusion

Our study revealed the genetically significant polymorphism concerning the ADRs and levodopa efficacy. The six common genes may be used as predictive markers for therapy optimization and as putative drug target candidates.

     

Aza-annulation on the 16-dehydropregnenolone, via tandem intermolecular aldol process and intramolecular Michael addition

16-Dehydropregnenolone undergoes a smooth annulation with propan-1-amine and aromatic aldehydes. Several amine derivatives of 16- dehydropregnenolone were synthesized and evaluated as inhibitors of DPP-IV. The structures of compounds were confirmed by ¹H, ¹³C, NMR and mass spectral analysis. Among 17 compounds evaluated only five compounds 1, 9, 13, 15 and 16 demonstrated significant inhibition of DPP. This study suggest that introduction of appropriate substituents in the 16-dehydropregnenolone plays an important role in DPP-IV inhibitory activity.     

Seed biopriming with drought tolerant isolates of Trichoderma harzianum promote growth and drought tolerance in Triticum aestivum

Green house study was aimed to investigate the effect of seed biopriming with drought tolerant isolates of Trichoderma harzianum, viz. Th 56, 69, 75, 82 and 89 on growth of wheat under drought stress and to explore the mechanism underlying plant water stress resilience in response to Trichoderma inoculation. Measurements of relative water content, osmotic potential, osmotic adjustment, leaf gas exchange, chlorophyll fluorescence and membrane stability index were performed. In addition, analysis of the phenolics, proline, lipid peroxidation and measurements of phenylalanine ammonia‐lyase activity were carried out. Seed biopriming enhanced drought tolerance of wheat as drought induced changes like stomatal conductance, net photosynthesis and chlorophyll fluorescence were delayed. Drought stress from 4 to 13 days of withholding water induced an increase in the concentration of stress induced metabolites in leaves, while Trichoderma colonisation caused decrease in proline, malondialdehyde (MDA) and hydrogen peroxide (H₂O₂), and an increase in total phenolics. A common factor that negatively affects plants under drought stress conditions is accumulation of toxic reactive oxygen species (ROS), and we tested the hypothesis that seed biopriming reduced damages resulting from accumulation of ROS in stressed plants. The enhanced redox state of colonised plants could be explained by higher l ‐phenylalanine ammonia‐lyase (PAL) activity in leaves after 13 days of drought stress in Trichoderma treated plants. Similar activity was induced in untreated plants in response to drought stress but to a lower extent in comparison to treated plants. Our results support the hypothesis that seed biopriming in wheat with drought tolerant T. harzianum strains increased root vigour besides performing the process of osmoregulation. It ameliorates drought stress by inducing physiological protection in plants against oxidative damage, due to enhanced capacity to scavenge ROS and increased level of PAL, a mechanism that is expected to augment tolerance to abiotic stresses.     

Identification of Escherichia coli through analysis of 16S rRNA and 16S-23S rRNA internal transcribed spacer region sequences

A bacterial strain, designated BzDS03 was isolated from water sample, collected from Dal Lake Srinagar. The strain was characterized by using 16S ribosomal RNA gene and 16S-23S rRNA internal transcribed spacer region sequences. Phylogenetic analysis showed that 16S rRNA sequence of the isolate formed a monophyletic clade with genera Escherichia. The closest phylogenetic relative was Escherichia coli with 99% 16S rRNA gene sequence similarity. The result of Ribosomal database project's classifier tool revealed that the strain BzDS03 belongs to genera Escherichia.16S rRNA sequence of isolate was deposited in GenBank with accession number FJ961336. Further analysis of 16S-23S rRNA sequence of isolate confirms that the identified strain BzDS03 be assigned as the type strain of Escherichia coli with 98% 16S-23S rRNA sequence similarity. The GenBank accession number allotted for 16S-23S rRNA intergenic spacer sequence of isolate is FJ961337.     

Antihyperglycemic activity of phenylpropanoyl esters of catechol glycoside and its dimers from Dodecadenia grandiflora

Bioactivity-guided separation of an antihyperglycemic extract from the leaves of Dodecadenia grandiflora afforded two phenylpropanoyl esters of catechol glycosides (1 and 4) and two lignane bis(catecol glycoside)esters (2 and 3). Their structures were established on the basis of extensive spectroscopic analysis (1D and 2D-NMR, MS). Compounds 2 and 3 are believed to be derived from dimerization via the two phenylpropanoid units of 1. Compounds 1–4 showed significant antihyperglycemic activity in streptozotocin-induced (STZ) diabetic rats, which is comparable to the standard drug metformin. Our results provide support to explain the use of D. grandiflora as antihyperglycemic agent by the traditional medical practitioners.