Release of free and conjugated forms of the putative pheromonal steroid 11-oxo-etiocholanolone by reproductively mature male round goby (Neogobius melanostomus Pallas, 1814)

Previous studies of the round goby (Neogobius melanostomus Pallas, 1814), an invasive fish species in the Laurentian Great Lakes of North America, have shown that this species has the ability to both synthesize and smell steroids that have a 5 beta-reduced and 3 alpha-hydroxyl (5 beta,3 alpha) configuration. An enzyme-linked immunoassay (EIA) for 3 alpha-hydroxy-5 beta-androstane-11,17-dione (11-O-ETIO) has been used to show a substantial rise in the rate of release of immunoreactive compounds into the water when males are injected with salmon gonadotropin releasing hormone analogue. Similar increases were noted for 11-ketotestosterone and 17,20 beta-dihydroxypregn-4-en-3-one. Partitioning of the extracts between diethyl ether and water showed the presence of both free and conjugated immunoreactive 11-O-ETIO. Only conjugated immunoreactivity was found in urine (implying that free steroid is released via the gills). The identity of the conjugates was probed by using HPLC, EIA, and mass spectrometry and removal of sulfate and glucosiduronate groups. Immunoreactivity in the conjugated fraction was found to be due mainly to 3 alpha,17beta-dihydroxy-5 beta-androstan-11-one 17-sulfate. However, the evidence was also strong for the presence in water extracts of substantial amounts of 3 alpha-hydroxy-5 beta-androstane-11,17-dione 3-glucosiduronate (which could be detected only by EIA after removal of the glucosiduronate group with beta-glucuronidase). There were also small amounts of 3 alpha-hydroxy-5 beta-androstane-11,17-dione 3-sulfate and 3 alpha,17beta-dihydroxy-5 beta-androstan-11-one 17-glucosiduronate. These studies give some idea of the types, amounts, and ratios of 11-O-ETIO derivatives that are released by reproductive N. melanostomus and will aid further research into the putative pheromonal roles of 5 beta,3 alpha-reduced androgens in this species.     

Thermodynamics of site-specific small molecular ion interactions with DNA duplex: a molecular dynamics study

The stability and dynamics of a double-stranded DNA (dsDNA) is affected by the preferential occupancy of small monovalent molecular ions. Small metal and molecular ions such as sodium and alkyl ammonium have crucial biological functions in human body, affect the thermodynamic stability of the duplex DNA and exhibit preferential binding. Here, using atomistic molecular dynamics simulations, we investigate the preferential binding of metal ion such as Na⁺ and molecular ions such as tetramethyl ammonium (TMA⁺) and 2-hydroxy-N,N,N-trimethylethanaminium (CHO⁺) to double-stranded DNA. The thermodynamic driving force for a particular molecular ion-DNA interaction is determined by decomposing the free energy of binding into its entropic and enthalpic contributions. Our simulations show that each of these molecular ions preferentially binds to the minor groove of the DNA and the extent of binding is highest for CHO⁺. The ion binding processes are found to be entropically favourable. In addition, the contribution of hydrophobic effects towards the entropic stabilisation (in case of TMA⁺) and the effect of hydrogen bonding contributing to enthalpic stabilisation (in case of CHO⁺) have also been investigated.     

Capturing the context of maternal deaths from verbal autopsies: a reliability study of the maternal data extraction tool (M-DET)

Background

The availability of quality data to inform policy is essential to reduce maternal deaths. To characterize maternal deaths in settings without complete vital registration systems, we designed and assessed the inter-rater reliability of a tool to systematically extract data and characterize the events that precede a nationally representative sample of maternal deaths in India.

Method/Principal Findings

Of 1017 nationally representative pregnancy-related deaths, which occurred between 2001 and 2003, we randomly selected 105 reports. Two independent coders used the maternal data extraction tool (questions with coding guidelines) to collect information on antenatal care access, final pregnancy outcome; planned place of birth and care provider; community consultation, transport, admission, hospital referral; and verification of cause of death assignment. Kappa estimated inter-rater agreement was calculated and classified as poor (K≤0.4), moderate (K = 0.4-≤0.6), substantial (K = 0.6-≤0.8) and high (K>0.8) using the criteria from Landis & Koch. The data extraction tool had high agreement for gestational age, pregnancy outcome, transport, death en route and admission to hospital; substantial agreement for receipt of antenatal care, planned place of birth, readmission and referral to higher level hospital, and whether or not death occurred in the intrapartum period; moderate to substantial agreement for classification of deaths as direct or indirect obstetric deaths or incidental deaths; moderate agreement for classification of community healthcare consultation and total number of healthcare contacts; and poor agreement for the classification of deaths as sudden deaths and other/unknown cause of death. The ability of the tool to identify the most-responsible-person in labour varied from moderate agreement to high agreement.

Conclusions

This data extraction tool achieved good inter-rater reliability and can be used to collect data on events surrounding maternal deaths and for verification/improvement of underlying cause of death.     

FBIS: A regional DNA barcode archival & analysis system for Indian fishes

DNA barcode is a new tool for taxon recognition and classification of biological organisms based on sequence of a fragment of mitochondrial gene, cytochrome c oxidase I (COI). In view of the growing importance of the fish DNA barcoding for species identification, molecular taxonomy and fish diversity conservation, we developed a Fish Barcode Information System (FBIS) for Indian fishes, which will serve as a regional DNA barcode archival and analysis system. The database presently contains 2334 sequence records of COI gene for 472 aquatic species belonging to 39 orders and 136 families, collected from available published data sources. Additionally, it contains information on phenotype, distribution and IUCN Red List status of fishes. The web version of FBIS was designed using MySQL, Perl and PHP under Linux operating platform to (a) store and manage the acquisition (b) analyze and explore DNA barcode records (c) identify species and estimate genetic divergence. FBIS has also been integrated with appropriate tools for retrieving and viewing information about the database statistics and taxonomy. It is expected that FBIS would be useful as a potent information system in fish molecular taxonomy, phylogeny and genomics. AVAILABILITY: The database is available for free at http://mail.nbfgr.res.in/fbis/     

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.     

Three novel collagen VI chains with high homology to the alpha3 chain

Here we describe three novel collagen VI chains, alpha4, alpha5, and alpha6. The corresponding genes are arranged in tandem on mouse chromosome 9. The new chains structurally resemble the collagen VI alpha3 chain. Each chain consists of seven von Willebrand factor A domains followed by a collagenous domain, two C-terminal von Willebrand factor A domains, and a unique domain. In addition, the collagen VI alpha4 chain carries a Kunitz domain at the C terminus, whereas the collagen VI alpha5 chain contains an additional von Willebrand factor A domain and a unique domain. The size of the collagenous domains and the position of the structurally important cysteine residues within these domains are identical between the collagen VI alpha3, alpha4, alpha5, and alpha6 chains. In mouse, the new chains are found in or close to basement membranes. Collagen VI alpha1 chain-deficient mice lack expression of the new collagen VI chains implicating that the new chains may substitute for the alpha3 chain, probably forming alpha1alpha2alpha4, alpha1alpha2alpha5, or alpha1alpha2alpha6 heterotrimers. Due to a large scale pericentric inversion, the human COL6A4 gene on chromosome 3 was broken into two pieces and became a non-processed pseudogene. Recently COL6A5 was linked to atopic dermatitis and designated COL29A1. The identification of novel collagen VI chains carries implications for the etiology of atopic dermatitis as well as Bethlem myopathy and Ullrich congenital muscular dystrophy.