Synthesis,characterization and in vitro biological evaluation of some novel 1,3,5-triazine–Schiff base conjugates as potential antimycobacterial agents

A series of some novel 1,3,5-triazine–Schiff base conjugates (1–32) have been synthesized and evaluated for their in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv using Alamar Blue assay and the activity expressed as the minimum inhibitory concentration (MIC) in μg/mL. Compounds 4 (4-Methoxy-6-methyl-N-(3,4,5-trimethoxybenzylidene)-1,3,5-triazin-2-amine), 11 (4-Methoxy-6-methyl-N-(2-hydroxy-3-bromo-5-chloro-benzylidene)-1,3,5-triazin-2-amine) and 24 (4-Methoxy-6-methyl-N-(1-(2,5-dihydroxyphenyl)ethylidene)-1,3,5-triazin-2-amine) exhibited a significant activity at 3.125, 6.25 and 6.25 μg/mL, respectively, when compared with the antitubercular drugs such as ethambutol (3.125 μg/mL), pyrazinamide (6.25 μg/mL) and streptomycin (6.25 μg/mL) and it could be a potential starting point to develop new lead compounds in the fight against Mycobacterium tuberculosis H37Rv.     

Isolation and characterization of ethanol tolerant yeast strains

Yeast strains are commonly associated with sugar rich environments. Various fruit samples were selected as source for isolating yeast cells. The isolated cultures were identified at Genus level by colony morphology, biochemical characteristics and cell morphological characters. An attempt has been made to check the viability of yeast cells under different concentrations of ethanol. Ethanol tolerance of each strain was studied by allowing the yeast to grow in liquid YEPD (Yeast Extract Peptone Dextrose) medium having different concentrations of ethanol. A total of fifteen yeast strains isolated from different samples were used for the study. Seven strains of Saccharomyces cerevisiae obtained from different fruit sources were screened for ethanol tolerance. The results obtained in this study show a range of tolerance levels between 7%-12% in all the stains. Further, the cluster analysis based on 22 RAPD (Random Amplified polymorphic DNA) bands revealed polymorphisms in these seven Saccharomyces strains.     

Characterization of the Two Intra-Individual Sequence Variants in the 18S rRNA Gene in the Plant Parasitic Nematode,Rotylenchulus reniformis

The 18S rRNA gene is fundamental to cellular and organismal protein synthesis and because of its stable persistence through generations it is also used in phylogenetic analysis among taxa. Sequence variation in this gene within a single species is rare, but it has been observed in few metazoan organisms. More frequently it has mostly been reported in the non-transcribed spacer region. Here, we have identified two sequence variants within the near full coding region of 18S rRNA gene from a single reniform nematode (RN) Rotylenchulus reniformis labeled as reniform nematode variant 1 (RN_VAR1) and variant 2 (RN_VAR2). All sequences from three of the four isolates had both RN variants in their sequences; however, isolate 13B had only RN variant 2 sequence. Specific variable base sites (96 or 5.5%) were found within the 18S rRNA gene that can clearly distinguish the two 18S rDNA variants of RN, in 11 (25.0%) and 33 (75.0%) of the 44 RN clones, for RN_VAR1 and RN_VAR2, respectively. Neighbor-joining trees show that the RN_VAR1 is very similar to the previously existing R. reniformis sequence in GenBank, while the RN_VAR2 sequence is more divergent. This is the first report of the identification of two major variants of the 18S rRNA gene in the same single RN, and documents the specific base variation between the two variants, and hypothesizes on simultaneous co-existence of these two variants for this gene.     

Abyssinones and related flavonoids as potential steroidogenesis modulators

Abyssinones and related flavonoids were screened against 3 enzymes (3βHSD, 17βHSD and Aromatase) of steroidogenesis pathway. The virtual screening experiment shows high affinity for flavonones than their respective chalcones. A 4'' ­OH blocked prenylated flavonone 2b (2­(2'', 2''­dimethyl chroman­6''­yl)­7­hydroxy chroman­4­one) had consistent binding affinity to all the three enzymes used in this study showing higher binding affinity to aromatase. A good correlation was observed between cytotoxic data (MCF­7, breast cancer cell line) and docking results indicating flavonone as a better steroidogenesis modulator in hormone dependent cancer.     

Frequency of occurrence of mangrove fungi from the east coast of India

This paper describes the frequency of occurrence and biodiversity of fungi from mangroves of the Godavari and Krishna deltas, on the east coast of India. Seventy three species were identified from Godavari and 67 from the Krishna mangroves. Fifty five species were common to both sites, 18 were found only at Godavari and 12 at Krishna mangroves. Verruculina enaliawas found to be very frequent at both sites with a higher frequency of occurrence at Godavari. Eutypa bathurstensis was very frequent at Godavari but only frequent at Krishna. Cirrenalia pygmea and Cryptosphaeria mangrovei were frequent at the Godavari mangrove, but were recorded occasionally at Krishna. Decaying samples of Rhizophora and Avicennia were studied in detail. Forty three species were common to both hosts, while 22 species were recorded only from Avicennia and 20 only from Rhizophora. Verruculina enalia was the only very frequent fungus recorded on both hosts with a lower percentage occurrence (14.8%) on R. apiculata as compared to Avicennia spp. (24.3%). Eutypa bathurstensis was the next most frequent fungus on Avicennia, while Rhizophila marina was next most frequent on Rhizophora. Dactylospora haliotrepha which was recorded frequently on Rhizophorawas infrequent on Avicennia.     

Mutations in exons 3 and 7 resulting in truncated expression of human ATP6V1B1 gene showing structural variations contributing to poor substrate binding-causative reason for distal renal tubular acidosis with sensorineural deafness

Distal renal tubular acidosis (dRTA) is an autosomal recessive syndrome results defect in either proximal tubule bicarbonate reabsorption or in distal tubule H⁺ secretion and is characterized by severe hyperchloraemic metabolic acidosis in childhood. dRTA is associated with functional variations in the ATP6V1B1 gene encoding β1 subunit of H⁺-ATPase, key membrane transporters for net acid excretion of α-intercalated cells of medullary collecting ducts. In the present study, a 13-year-old male patient suffering with nephropathy and sensorineural deafness was reported in the Department of Nephrology. We predicted improper functioning of ATP6V1B1 gene could be the reason for diseased condition. Therefore, exons 3, 4, and 7 contributing active site of ATP6V1B1 gene was amplified and sequenced (Accession numbers: KF571726, KM222653). The obtained sequences were BLAST searched against the wild type ATP6V1B1 gene which showed novel mutations c.307 A > G, c.308 C > A, c.310 C > G, c.704 T > C, c.705 G > T, c.709 A > G, c.710 A > G, c.714 G > A, c.716 C > A, c.717delC, c.722 C > G, c.728insG, c.741insT, c.753G > C. These mutations resulted in the expression of truncated protein terminating at Lys 209. The mutated ATP6V1B1structure superimposed with wild type showed extensive variations with RMSD 1.336 Å and could not bind to substrate ADP leading to non-functional ATPase. These results conclusively explain these mutations in ATP6V1B1 gene resulted in structural changes causing accumulation of H⁺ ions contributing to dRTA with sensorineural deafness.     

Selective inhibition of cyclooxygenase-2 (COX-2) by 1alpha,25-dihydroxy-16-ene-23-yne-vitamin D3, a less calcemic vitamin D analog

Inducible cyclooxygenase-2 (COX-2) has been implicated to play a role in inflammation and carcinogenesis and selective COX-2 inhibitors have been considered as anti-inflammatory and cancer chemopreventive agents. 1alpha,25-dihydroxyvitamin D3 (1alpha,25(OH)2D3), the active hormonal form of vitamin D3 also has been considered to be a cancer chemopreventive agent in addition to its important role in maintaining calcium homeostasis. Based on these observations, we studied the direct effect of 1alpha,25(OH)2D3 and one of its less calcemic synthetic analogs, 1alpha,25(OH)2-16-ene-23-yne-D3 on the activity of both COX-1 and COX-2 in an in vitro enzyme assay. Preliminary data indicated that both 1alpha,25(OH)2D3 and 1alpha,25(OH)2-16-ene-23-yne-D3 inhibited selectively the activity of COX-2 with no effect on the activity of COX-1. Out of the two compounds, 1alpha,25(OH)2-16-ene-23-yne-D3 was found to be more effective with an IC50 of 5.8 nM. Therefore, the rest of the experiments were performed using 1alpha,25(OH)2-16-ene-23-yne-D3 only. 1alpha,25(OH)2-16-ene-23-yne-D3 inhibited the proliferation of lipopolysaccharide (LPS) stimulated mouse macrophage cells (RAW 264.7) with a reduction in the expression of COX-2 along with other inflammatory mediators like inducible nitric oxide synthase (iNOS) and interleukin-2 (IL-2). Furthermore, 1alpha,25(OH)2-16-ene-23-yne-D3 also inhibited carrageenan induced inflammation in an air pouch of a rat and effectively reduced the expression of COX-2, iNOS, and IL-2 in the tissues of the same air pouch. In both cases, 1alpha,25(OH)2-16-ene-23-yne-D3 did not show any effect on the expression of COX-1. In summary, our results indicate that 1alpha,25(OH)2-16-ene-23-yne-D3, a less calcemic vitamin D analog, exhibits potent anti-inflammatory effects and is a selective COX-2 inhibitor.