Effect of Ocimum sanctum Linn. on normal and dexamethasone suppressed wound healing

Ethanolic extract of leaves of O. sanctum was investigated for normal wound healing and dexamethasone depressed healing using incision, excision and dead space wound models in albino rats. The extract of O. sanctum significantly increased the wound breaking strength in incision wound model. The extract treated wounds were found to epithelialize faster and the rate of wound contraction was significantly increased as compared to control wounds. Significant increase in wet and dry granulation tissue weight, granulation tissue breaking strength and hydroxyproline content in dead space wound model was observed. The extract significantly decreased the antihealing activities of dexamethasone in all the wound models. The results indicated that the leaf extract promotes wound healing significantly and able to overcome the wound healing suppressing action of dexamethasone. Histological examination of granulation tissue to determine the pattern of lay-down for collagen confirmed the results.     

Delineating metabolic signatures of head and neck squamous cell carcinoma: Phospholipase A(2), a potential therapeutic target

A better understanding of molecular pathways involved in malignant transformation of head and neck squamous cell carcinoma (HNSCC) is essential for the development of novel and efficient anti-cancer drugs. To delineate the global metabolism of HNSCC, we report (1)H NMR-based metabolic profiling of HNSCC cells from five different patients that were derived from various sites of the upper aerodigestive tract, including the floor of mouth, tongue and larynx. Primary cultures of normal human oral keratinocytes (NHOK) from three different donors were used for comparison. (1)H NMR spectra of polar and non-polar extracts of cells were used to identify more than thirty-five metabolites. Principal component analysis performed on the NMR data revealed a clear classification of NHOK and HNSCC cells. HNSCC cells exhibited significantly altered levels of various metabolites that clearly revealed dysregulation in multiple metabolic events, including Warburg effect, oxidative phosphorylation, energy metabolism, TCA cycle anaplerotic flux, glutaminolysis, hexosamine pathway, osmo-regulatory and anti-oxidant mechanism. In addition, significant alterations in the ratios of phosphatidylcholine/lysophosphatidylcholine and phosphocholine/glycerophosphocholine, and elevated arachidonic acid observed in HNSCC cells reveal an altered membrane choline phospholipid metabolism (MCPM). Furthermore, significantly increased activity of phospholipase A(2) (PLA(2)), particularly cytosolic PLA(2) (cPLA(2)) observed in all the HNSCC cells confirm an altered MCPM. In summary, the metabolomic findings presented here can be useful to further elucidate the biological aspects that lead to HNSCC, and also provide a rational basis for monitoring molecular mechanisms in response to chemotherapy. Moreover, cPLA(2) may serve as a potential therapeutic target for anti-cancer therapy of HNSCC.     

Aluminum-mediated metabolic changes in rat serum and urine: a proton nuclear magnetic resonance study

The toxic effects of Al(3+) have been studied in 90-days AlCl(3) orally treated male albino rats (n = 7) using (1)H NMR spectroscopy-based metabolic profile of rat serum and urine, serum enzyme tests, behavioral impairment, and histopathology of kidney and liver. Metabolic profile of 90-days Al(3+)-treated rat sera showed significantly elevated levels of alanine, glutamine, beta-hydroxy-butyrate, and acetoacetate and significantly decreased level of acetone when compared with that of control rats. However, metabolic profile of 90-days Al(3+)-treated rat urine showed significantly decreased levels of citrate, creatinine, allantoin, trans-aconitate, and succinate and significantly increased level of acetate when compared to control rats. The overall perturbations observed in the metabolic profile of serum and urine demonstrate the impairment in the tricarboxylic acid cycle, liver and kidney metabolism, which was further reinstated by clinical chemistry and histopathological observations. Moreover, "in vivo" behavioral impairment has also been observed as the indication of aluminum neurotoxicity.     

New Insights into the Early Steps of Phosphatidylinositol Mannoside Biosynthesis in Mycobacteria: PimB�� IS AN ESSENTIAL ENZYME OF MYCOBACTERIUM SMEGMATIS*

Phosphatidyl-myo-inositol mannosides (PIMs) are key glycolipids of the mycobacterial cell envelope. They are considered not only essential structural components of the cell but also important molecules implicated in host-pathogen interactions. Although their chemical structures are well established, knowledge of the enzymes and sequential events leading to their biosynthesis is still incomplete. Here we show for the first time that although both mannosyltransferases PimA and PimB′ (MSMEG_4253) recognize phosphatidyl-myo-inositol (PI) as a lipid acceptor, PimA specifically catalyzes the transfer of a Manp residue to the 2-position of the myo-inositol ring of PI, whereas PimB′ exclusively transfers to the 6-position. Moreover, whereas PimB′ can catalyze the transfer of a Manp residue onto the PI-monomannoside (PIM₁) product of PimA, PimA is unable in vitro to transfer Manp onto the PIM₁ product of PimB′. Further assays using membranes from Mycobacterium smegmatis and purified PimA and PimB′ indicated that the acylation of the Manp residue transferred by PimA preferentially occurs after the second Manp residue has been added by PimB′. Importantly, genetic evidence is provided that pimB′ is an essential gene of M. smegmatis. Altogether, our results support a model wherein Ac₁PIM₂, a major form of PIMs produced by mycobacteria, arises from the consecutive action of PimA, followed by PimB′, and finally the acyltransferase MSMEG_2934. The essentiality of these three enzymes emphasizes the interest of novel anti-tuberculosis drugs targeting the initial steps of PIM biosynthesis.PIMs³ are unique mannolipids found in abundant quantities in the inner and outer membranes of the cell envelope of Mycobacterium spp. and a few other actinomycetes.⁴ They are based on a phosphatidyl-myo-inositol (PI) lipid anchor carrying one to six Manp residues and up to four acyl chains (for review see Refs. 1, 2). Based on a conserved mannosyl-PI anchor, they are also thought to be the precursors of the two major mycobacterial lipoglycans, lipomannan (LM) and lipoarabinomannan (LAM) (1, 2). PIMs, LM, and LAM are considered not only essential structural components of the mycobacterial cell envelope (3–6), but also important molecules implicated in host-pathogen interactions in the course of tuberculosis and leprosy (1).Although the chemical structure of PIMs is now well established, knowledge of the enzymes and sequential events leading to their biosynthesis is still fragmentary. According to the currently accepted model, the biosynthetic pathway is initiated by the transfer of two Manp residues and a fatty acyl chain to PI in the cytoplasmic leaflet of the plasma membrane. Based on genetic and biochemical evidence, Korduláková et al. (5) identified PimA (MSMEG_2935 in Mycobacterium smegmatis mc²155) as the enzyme that catalyzes the first mannosylation step of the pathway transferring a Manp residue most likely to the 2-position of the myo-inositol (myo-Ins) ring of PI. In contrast, the identity of PimB′, the enzyme responsible for the transfer of the second Manp to the 6-position of the myo-Ins ring of PIM₁, still remains controversial. The Rv0557 protein of Mycobacterium tuberculosis H37Rv (PimB; MSMEG_1113 in M. smegmatis mc²155) was originally characterized as PimB′ (7). However, the lack of an Rv0557 ortholog in the genome of Mycobacterium leprae and the fact that the disruption of this gene in M. tuberculosis Erdman did not significantly affect the biosynthesis of PIMs suggest that compensatory activities exist in the bacterium or that Rv0557 serves another primary function (8, 9). Somewhat supporting the latter hypothesis, the ortholog of Rv0557 in Corynebacterium glutamicum (NCgl0452, renamed mgtA) was implicated in the mannosylation of a novel glycolipid (1,2-di-O-C₁₆/C_18:1-(α-d-mannosyl)-(1→4)-(α-d-glucopyranosyluronic acid)-(1→3)-glycerol), and Rv0557 from M. tuberculosis was reported to functionally complement for this enzyme in a C. glutamicum knock-out mutant (10). However, to our knowledge this mannosylated glycolipid has never been reported in mycobacteria, and it remains unclear whether PimB serves a similar physiological function in Mycobacterium spp.More recently, Lea-Smith et al. (11) have shown that the biosynthesis of Ac₁PIM₂ from Ac₁PIM₁ in C. glutamicum is catalyzed by NCgl2106 (Cg-PimB′). Disruption of the NCgl2106 gene totally abolished Ac₁PIM₂ production in the mutant, arguing against the existence of a compensatory activity associated with the corynebacterial PimB enzyme. Although Ac₁PIM₂ production in Cg-pimB′ and Cg-pimB′/Cg-pimB knock-out mutants was restored upon complementation with the M. tuberculosis Rv2188c gene (11, 12), direct evidence that Rv2188c carried out the same physiological function in mycobacteria has been lacking. Moreover, in light of the recent work by Torrelles et al. (9) showing an involvement of pimB (Rv0557) in the synthesis of LM and LAM in M. tuberculosis Erdman and of the demonstrated relaxed substrate specificity of the M. tuberculosis PimB (Rv0557) and PimB′ (Rv2188c) enzymes expressed in C. glutamicum (12), whether or not pimB and pimB′ could compensate for one another in mycobacteria remained open to speculation.Both PIM₁ and PIM₂ can be acylated with palmitate at position 6 of the Manp residue transferred by PimA by the acyltransferase MSMEG_2934 (orthologous to Rv2611c from M. tb) to form Ac₁PIM₁ and Ac₁PIM₂, respectively (13). Ac₁PIM₂ can further be acylated at position 3 of the myo-Ins ring by an as yet unidentified acyltransferase to yield Ac₂PIM₂. Importantly, Ac₁PIM₂ and Ac₂PIM₂ are among the most abundant forms of PIMs found in mycobacteria and are considered both metabolic end products and intermediates in the biosynthesis of more polar forms of PIMs (PIM₅ and PIM₆), LM, and LAM.In this work, clear evidence is provided that PimB′ (MSMEG_4253 in M. smegmatis mc²155) is the α-ManT responsible for the biosynthesis of PIM₂ from PIM₁ in mycobacteria and that no other ManT can compensate for a deficiency in this enzyme in M. smegmatis. Like PimA (5), PimB′ is essential to the growth of M. smegmatis. Cell-free assays using purified PimA and PimB′ and M. smegmatis membrane preparations provide new insights into the sequential events leading to the synthesis of the early forms of PIMs in mycobacteria.     

Lipase catalyzed synthesis of l-alanyl, l-leucyl and l-phenylalanyl esters of d-glucose using unprotected amino acids

Enzymatic synthesis of l-alanyl, l-leucyl and l-phenylalanyl esters of D-glucose was carried out in a non-polar solvent using lipases from Rhizomucor miehei and porcine pancreas. The unprotected amino acids at millimolar concentrations were used in presence of 10 to 50% (w/w) glucose of the lipases to give ester yields up to >99%. The reaction mixture on analysis by 2-D NMR showed that the product is a mixture of 6-O-, 3-O- and 2-O-monoesters and 2,6-di-O- and 3,6- di-O-esters.     

Prevalence of Pulmonary Tuberculosis among Adults in a Rural Sub-District of South India

Background

We conducted a survey to estimate point prevalence of bacteriologically positive pulmonary TB (PTB) in a rural area in South India, implementing TB program DOTS strategy since 2002.

Methods

Survey was conducted among persons ≥15 years of age in fifteen clusters selected by simple random sampling; each consisting of 5–12 villages. Persons having symptoms suggestive of PTB or history of anti-TB treatment (ATT) were eligible for sputum examination by smear microscopy for Acid Fast Bacilli and culture for Mycobacterium tuberculosis; two sputum samples were collected from each eligible person.Persons with one or both sputum specimen positive on microscopy and/or culture were labeled suffering from PTB. Prevalence was estimated after imputing missing values to correct for bias introduced by incompleteness of data.In six clusters, registered persons were also screened by X-ray chest. Persons with any abnormal shadow on X-ray were eligible for sputum examination in addition to those with symptoms and ATT. Multiplication factor calculated as ratio of prevalence while using both screening tools to prevalence using symptoms screening alone was applied to entire study population to estimate prevalence corrected for non-screening by X-ray.

Results

Of 71,874 residents ≥15 years of age, 63,362 (88.2%) were screened for symptoms and ATT. Of them, 5120 (8.1%) - 4681 (7.4%) with symptoms and an additional 439 (0.7%) with ATT were eligible for sputum examination. Spot specimen were collected from 4850 (94.7%) and early morning sputum specimens from 4719 (92.2%). Using symptom screening alone, prevalence of smear, culture and bacteriologically positive PTB in persons ≥15 years of age was 83 (CI: 57–109), 152 (CI: 108–197) and 196 (CI :145–246) per 100,000 population respectively. Prevalence corrected for non-screening by X-ray was 108 (CI: 82–134), 198 (CI: 153–243) and 254 (CI: 204–301) respectively.

Conclusion

Observed prevalence suggests further strengthening of TB control program.     

Determinants of plant species invasions in an arid island: evidence from Socotra Island (Yemen)

Understanding the factors which affect the distribution of alien plants in arid islands is complicated by the complex and stochastic nature of the invasion process per se, the harsh environmental conditions, and the low number of researchers and sampling effort. We present the results of the most comprehensive inventory to date of alien vascular plant species occurring in Socotra Island, a global biodiversity hotspot just beginning to be developed. A floristic survey was conducted between 2006 and 2008 in 36 grid cells of 10?×?10?km. We integrated this data from this survey with those from scientific literature. We recorded 88 alien plant species. Tree and herbaceous species were the most common growth forms. Species from Asia and edible species were prevalent. We identified 80 species considered weeds worldwide with >50?% adapted to arid conditions. We used a two-part model to analyze the spatial distribution of naturalized and alien plant species in relation to environmental and anthropogenic factors. Altitude and human-related factors play a significant role in the distribution of both naturalized and invasive species. Notably, the latter can potentially spread mainly in the alluvial basal areas. This study underpins the knowledge about alien species and their spatial distribution in Socotra Island. It provides a baseline for plant invasion management and contributes data for the analyses of invasion processes on islands worldwide.     

Heavy Metal Contamination in Roadside Soil and Their Mobility in Relations to pH and Organic Carbon

Concentrations of Pb, Zn, Cd, Ni, Cu, Cr, and Mn were determined to assess the impact of automobiles on heavy metal contamination of roadside soil. Soil samples at four polluted sites and a control site were collected at a depth of 0, 2, 5, 10, 15, 20, 30?cm. A comparison of elemental levels between polluted and control sites exhibited exceptionally higher concentrations at the former sites. The Pb levels in polluted sites varied from 70 to 280.5?µgg^?1and it rapidly decreased with depth. Similarly, mean concentrations of Zn, Cd, Ni, Cu, Cr, and Mn were significantly higher at polluted sites and followed a decreasing trend with the increase in depth. Correlation coefficients between heavy metals and traffic density were positively significant except for nickel. Profile samples showed that Pb, Zn, Cd, Cu, and Mn were largely concentrated in the top 5?cm confirming airborne contamination. The vertical movement and partitioning of metals, except Ni and Cr, exhibited predominant association with soil pH and organic carbon. The results have been presented using Heavy Metal Index.     

Induction of colony morphology variation inRhodotorula gracilis by UV irradiation

Nonlethal UV irradiation induced an unusually high frequency of colony morphology variation inRhodotorula gracilis. The variation was not fixed but indicated further variability in subsequent platings. Microscopic examination of the cultures indicated that UV-irradiated variants had grossly varying types of shapes and arrangements of cells in contrast to the uniformly shaped and budding cells of the nonirradiated culture. Flow-cytometric analysis of a colony variant suggested a slightly higher proportion of cells with variable DNA content than the nonirradiated culture. Extensive biochemical characterization revealed only one difference in that the nonirradiated culture had a partial requirement for pantothenate while the colony variant was completely independent of this requirement. We speculate that UV triggers a yet unstudied means of variability inR. gracilis with possible accompanying recombinational events.