41 research outputs found
Ecology, distribution mapping and population structure of Trichopus zeylanicus subsp. travancoricus (Arogyapacha)
Trichopus zeylanicus subsp. travancoricus (Bedd.) Burkill ex K. Narayanan (Arogyapacha) is an ethnomedically important perennial herb with a restricted distribution in the southern Western Ghats, India. Habitat specifications reveal that suitable areas for this species occur at elevations ranging from 100 to 1000 m above sea level. A study was conducted to gain insights into the ecology, distribution mapping and population structure of T. zeylanicus subsp. travancoricus in the Western Ghats. The spatial distribution of this endemic species showed significant variations among populations. Seven populations were identified, exhibiting large and small distributional patches, even within a single population. Anthropogenic activities and climate-related shifts in ecophysiology have impacted seed dispersal, canopy gap formation and seedling mortality, altering vegetation composition. Observations indicated a disturbed ecological niche, fragmented habitat and patchy occurrence of this species. The vegetation data for T. zeylanicus subsp. travancoricus showed significant variations among the seven populations. The Kulathupuzha population exhibited higher recruitment rates and density than others. Canopy cover analysis revealed that populations with closed canopies influenced seedling recruitment and density. However, populations with moderately closed canopies displayed variable characteristics, with Kulathupuzha standing out for its higher recruitment rate and reproductive capacity
Conservation of Garcinia imberti Bourd. through seeds
Garcinia imberti seeds were collected during 2015-2017 from Shangili, Cheenikkala and Bonaccord evergreen forests of Agasthyamala Biosphere Reserve, the only abode of this endangered endemic species. Germinability of seeds were analysed through decoating, Gibberellic acid (GA3) and light inductive pre-treatments on fresh (62.8 % moisture content; MC) and desiccated (fast; 23.3% MC and slow; 30.5 % MC) seeds. The seed germination with impermeable coat (0.7-1.2 mm) was restricted which on decoating got enhanced. Application of GA3 along with exposure to light breaked dormancy within 4-6 days compared to non-treated seeds that took 238-254 days to germinate. Stored seeds behaviour revealed that seed moisture content and rate of germination were negatively correlated. Seed storage was found to be more efficient only up to 80 days at controlled seed banking conditions (20 ± 20C, 20 % relative humidity; RH). Both fast and slow desiccated seeds stored for 60 days in seed bank conditions exhibited 50.4 and 43.4 % of germination compared 39.4% germination of non-desiccated seeds. Hence fast desiccated and decoated G. imberti seeds pre-treated with GA3 on subsequent exposure to light alleviated dormancy. For seed banking, fast desiccated seeds with MC in between 40-20% are found to be promising
The feasibility of integrating alcohol risk-reduction counseling into existing VCT services in Kenya
This pretest-posttest separate-sample study with intervention and comparison groups documented the abilities and willingness of trained voluntary counseling and testing (VCT) service providers to integrate alcohol screening and risk reduction counseling into their routine service delivery. Pre-test (n=1073) and post-test data (n=1058) were collected from different clients exiting from 25 VCT centers. A 12-month intervention that required all VCT providers from the intervention groups to screen all VCT clients for their alcohol use and offer them brief risk reduction alcoholrelated counseling was implemented. At post-test, the intervention group clients (n=456) had better study outcomes than the comparison group clients (n=602). Intervention clients were more likely to report that their VCT service provider had: asked them about their alcohol use (83% vs. 41%:
Cell Surface Remodeling of Mycobacterium abscessus under Cystic Fibrosis Airway Growth Conditions.
Understanding the physiological processes underlying the ability of Mycobacterium abscessus to become a chronic pathogen of the cystic fibrosis (CF) lung is important to the development of prophylactic and therapeutic strategies to better control and treat pulmonary infections caused by these bacteria. Gene expression profiling of a diversity of M. abscessus complex isolates points to amino acids being significant sources of carbon and energy for M. abscessus in both CF sputum and synthetic CF medium and to the bacterium undergoing an important metabolic reprogramming in order to adapt to this particular nutritional environment. Cell envelope analyses conducted on the same representative isolates further revealed unexpected structural alterations in major cell surface glycolipids known as the glycopeptidolipids (GPLs). Besides showing an increase in triglycosylated forms of these lipids, CF sputum- and synthetic CF medium-grown isolates presented as yet unknown forms of GPLs representing as much as 10% to 20% of the total GPL content of the cells, in which the classical amino alcohol located at the carboxy terminal of the peptide, alaninol, is replaced with the branched-chain amino alcohol leucinol. Importantly, both these lipid changes were exacerbated by the presence of mucin in the culture medium. Collectively, our results reveal potential new drug targets against M. abscessus in the CF airway and point to mucin as an important host signal modulating the cell surface composition of this pathogen
Regulation of mycolactone, the Mycobacterium ulcerans toxin, depends on nutrient source
BACKGROUND:
Mycobacterium ulcerans, a slow-growing environmental bacterium, is the etiologic agent of Buruli ulcer, a necrotic skin disease. Skin lesions are caused by mycolactone, the main virulence factor of M. ulcerans, with dermonecrotic (destruction of the skin and soft tissues) and immunosuppressive activities. This toxin is secreted in vesicles that enhance its biological activities. Nowadays, it is well established that the main reservoir of the bacilli is localized in the aquatic environment where the bacillus may be able to colonize different niches. Here we report that plant polysaccharides stimulate M. ulcerans growth and are implicated in toxin synthesis regulation.
METHODOLOGY/PRINCIPAL FINDINGS:
In this study, by selecting various algal components, we have identified plant-specific carbohydrates, particularly glucose polymers, capable of stimulating M. ulcerans growth in vitro. Furthermore, we underscored for the first time culture conditions under which the polyketide toxin mycolactone, the sole virulence factor of M. ulcerans identified to date, is down-regulated. Using a quantitative proteomic approach and analyzing transcript levels by RT-qPCR, we demonstrated that its regulation is not at the transcriptional or translational levels but must involve another type of regulation. M. ulcerans produces membrane vesicles, as other mycobacterial species, in which are the mycolactone is concentrated. By transmission electron microscopy, we observed that the production of vesicles is independent from the toxin production. Concomitant with this observed decrease in mycolactone production, the production of mycobacterial siderophores known as mycobactins was enhanced.
CONCLUSIONS/SIGNIFICANCE:
This work is the first step in the identification of the mechanisms involved in mycolactone regulation and paves the way for the discovery of putative new drug targets in the future
Globally, songs and instrumental melodies are slower and higher and use more stable pitches than speech: a Registered Report
Both music and language are found in all known human societies, yet no studies have compared similarities and differences between song, speech, and instrumental music on a global scale. In this Registered Report, we analyzed two global datasets: (i) 300 annotated audio recordings representing matched sets of traditional songs, recited lyrics, conversational speech, and instrumental melodies from our 75 coauthors speaking 55 languages; and (ii) 418 previously published adult-directed song and speech recordings from 209 individuals speaking 16 languages. Of our six preregistered predictions, five were strongly supported: Relative to speech, songs use (i) higher pitch, (ii) slower temporal rate, and (iii) more stable pitches, while both songs and speech used similar (iv) pitch interval size and (v) timbral brightness. Exploratory analyses suggest that features vary along a “musi-linguistic” continuum when including instrumental melodies and recited lyrics. Our study provides strong empirical evidence of cross-cultural regularities in music and speech
Reconstitution of functional mycobacterial arabinosyltransferase AftC proteoliposome and assessment of decaprenylphosphorylarabinose analogues as arabinofuranosyl donors.
Arabinosyltransferases are a family of membrane-bound glycosyltransferases involved in the biosynthesis of the arabinan segment of two key glycoconjugates, arabinogalactan and lipoarabinomannan, in the mycobacterial cell wall. All arabinosyltransferases identified have been found to be essential for the growth of Mycobcterium tuberculosis and are potential targets for developing new antituberculosis drugs. Technical bottlenecks in designing enzyme assays for screening for inhibitors of these enzymes are (1) the enzymes are membrane proteins and refractory to isolation; and (2) the sole arabinose donor, decaprenylphosphoryl-d-arabinofuranose is sparingly produced and difficult to isolate, and commercial substrates are not available. In this study, we have synthesized several analogues of decaprenylphosphoryl-d-arabinofuranose by varying the chain length and investigated their arabinofuranose (Araf) donating capacity. In parallel, an essential arabinosyltransferase (AftC), an enzyme that introduces α-(1→3) branch points in the internal arabinan domain in both arabinogalactan and lipoarabinomannan synthesis, has been expressed, solubilized, and purified for the first time. More importantly, it has been shown that the AftC is active only when reconstituted in a proteoliposome using mycobacterial phospholipids and has a preference for diacylated phosphatidylinositoldimannoside (Ac(2)PIM(2)), a major cell wall associated glycolipid. α-(1→3) branched arabinans were generated when AftC-liposome complex was used in assays with the (Z,Z)-farnesylphosphoryl d-arabinose and linear α-d-Araf-(1→5)(3-5) oligosaccharide acceptors and not with the acceptor that had a α-(1→3) branch point preintroduced
A Spherical Tensor Method for Pure NQR
The multipole operator technique is used to exploit the rotational invariance of the Hamiltonian. The technique and its effectiveness for the pure quadrupole hamiltonian with arbitrary asymmetry parameter are discussed for spins ≦ 5/2. The time evolution of the quadrupolar alignment tensor is presented analytically for various spins. The dynamics of the full density matrix are given.</jats:p
Conservation of Garcinia imberti Bourd. through seeds
Garcinia imberti seeds were collected during 2015-2017 from Shangili, Cheenikkala and Bonaccord evergreen forests of Agasthyamala Biosphere Reserve, the only abode of this endangered endemic species. Germinability of seeds were analysed through decoating, Gibberellic acid (GA3) and light inductive pre-treatments on fresh (62.8 % moisture content; MC) and desiccated (fast; 23.3% MC and slow; 30.5 % MC) seeds. The seed germination with impermeable coat (0.7-1.2 mm) was restricted which on decoating got enhanced. Application of GA3 along with exposure to light breaked dormancy within 4-6 days compared to non-treated seeds that took 238-254 days to germinate. Stored seeds behaviour revealed that seed moisture content and rate of germination were negatively correlated. Seed storage was found to be more efficient only up to 80 days at controlled seed banking conditions (20 ± 20C, 20 % relative humidity; RH). Both fast and slow desiccated seeds stored for 60 days in seed bank conditions exhibited 50.4 and 43.4 % of germination compared 39.4% germination of non-desiccated seeds. Hence fast desiccated and decoated G. imberti seeds pre-treated with GA3 on subsequent exposure to light alleviated dormancy. For seed banking, fast desiccated seeds with MC in between 40-20% are found to be promising.</jats:p
