Albirhodobacter marinus gen. nov., sp. nov., a member of the family Rhodobacteraceae isolated from sea shore water of Visakhapatnam, India

A novel marine, Gram-negative, rod-shaped bacterium, designated strain N9^T, was isolated from a water sample of the sea shore at Visakhapatnam, Andhra Pradesh (India). Strain N9^T was found to be positive for oxidase and catalase activities. The fatty acids were found to be dominated by C_16:0, C_18:1 ω7c and summed in feature 3 (C_16:1 ω7c and/or C_16:1 ω6c). Strain N9^T was determined to contain Q-10 as the major respiratory quinone and phosphatidylethanolamine, phosphatidylglycerol, two aminophospholipids, two phospholipids and four unidentified lipids as polar lipids. The DNA G+C content of the strain N9^T was found to be 63 mol%. 16S rRNA gene sequence analysis indicated that Rhodobacter sphaeroides, Rhodobacter johrii, Pseudorhodobacter ferrugineus, Rhodobacter azotoformans, Rhodobacter ovatus and Pseudorhodobacter aquimaris were the nearest phylogenetic neighbours, with pair-wise sequence similarities of 95.43, 95.36, 94.24, 95.31, 95.60 and 94.74 %, respectively. Phylogenetic analysis showed that strain N9^T formed a distinct branch within the family Rhodobacteraceae and clustered with the clade comprising species of the genus Pseudorhodobacter, together with species of the genera Roseicitreum, Roseinatronobacter, Roseibaca and Rhodobaca. Species of the genus Pseudorhodobacter are phylogenetically close with a 16S rRNA gene sequence dissimilarity of 5.9–7.3 % (92.7–94.1 % similarity). Based on the above-mentioned phenotypic characteristics and on phylogenetic inference, strain N9^T is proposed as a representative of a new genus and a novel species of the family Rhodobacteraceae as Albirhodobacter marinus gen. nov., sp. nov. The type strain of Albirhodobacter marinus is N9 (= MTCC 11277^T = JCM 17680^T).     

Exploitation of marine bacteria for production of gold nanoparticles

Background

Gold nanoparticles (AuNPs) have found wide range of applications in electronics, biomedical engineering, and chemistry owing to their exceptional opto-electrical properties. Biological synthesis of gold nanoparticles by using plant extracts and microbes have received profound interest in recent times owing to their potential to produce nanoparticles with varied shape, size and morphology. Marine microorganisms are unique to tolerate high salt concentration and can evade toxicity of different metal ions. However, these marine microbes are not sufficiently explored for their capability of metal nanoparticle synthesis. Although, marine water is one of the richest sources of gold in the nature, however, there is no significant publication regarding utilization of marine micro-organisms to produce gold nanoparticles. Therefore, there might be a possibility of exploring marine bacteria as nanofactories for AuNP biosynthesis.

Results

In the present study, marine bacteria are exploited towards their capability of gold nanoparticles (AuNPs) production. Stable, monodisperse AuNP formation with around 10?nm dimension occur upon exposure of HAuCl₄ solution to whole cells of a novel strain of Marinobacter pelagius, as characterized by polyphasic taxonomy. Nanoparticles synthesized are characterized by Transmission electron microscopy, Dynamic light scattering and UV-visible spectroscopy.

Conclusion

The potential of marine organisms in biosynthesis of AuNPs are still relatively unexplored. Although, there are few reports of gold nanoparticles production using marine sponges and sea weeds however, there is no report on the production of gold nanoparticles using marine bacteria. The present work highlighted the possibility of using the marine bacterial strain of Marinobacter pelagius to achieve a fast rate of nanoparticles synthesis which may be of high interest for future process development of AuNPs. This is the first report of AuNP synthesis by marine bacteria.     

L<Subscript>2</Subscript>-norm multiple kernel learning and its application to biomedical data fusion

Background  

This paper introduces the notion of optimizing different norms in the dual problem of support vector machines with multiple kernels. The selection of norms yields different extensions of multiple kernel learning (MKL) such as L _∞, L ₁, and L ₂ MKL. In particular, L ₂ MKL is a novel method that leads to non-sparse optimal kernel coefficients, which is different from the sparse kernel coefficients optimized by the existing L _∞ MKL method. In real biomedical applications, L ₂ MKL may have more advantages over sparse integration method for thoroughly combining complementary information in heterogeneous data sources.     

Comparative analysis of DNA polymorphisms and phylogenetic relationships among Syzygium cumini Skeels based on phenotypic characters and RAPD technique

The Indian black berry (Syzygium cumini Skeels) has a great nutraceutical and medicinal properties. As in other fruit crops, the fruit characteristics are important attributes for differentiation were also determined for different accessions of S. cumini. The fruit weight, length, breadth, length: breadth ratio, pulp weight, pulp content, seed weight and pulp: seed ratio significantly varied in different accessions. Molecular characterization was carried out using PCR based RAPD technique. Out of 80 RAPD primers, only 18 primers produced stable polymorphisms that were used to examine the phylogenetic relationship. A sum of 207 loci were generated out of which 201 loci found polymorphic. The average genetic dissimilarity was 97 per cent among jamun accessions. The phylogenetic relationship was also determined by principal coordinates analysis (PCoA) that explained 46.95 per cent cumulative variance. The two-dimensional PCoA analysis showed grouping of the different accessions that were plotted into four sub-plots, representing clustering of accessions. The UPGMA (r = 0.967) and NJ (r = 0.987) dendrogram constructed based on the dissimilarity matrix revealed a good degree of fit with the cophenetic correlation value. The dendrogram grouped the accessions into three main clusters according to their eco-geographical regions which given useful insight into their phylogenetic relationships.     

不同耕作措施对冬小麦-夏玉米复种连作系统土壤有机碳和水分利用效率的影响

在连续8年田间定位试验的基础上,分析了关中平原冬小麦 夏玉米复种连作系统2008—2009年连续两个生长季期间不同耕作措施(结合秸秆还田和不还田)对土壤有机碳和水分利用率的影响.结果表明: 相对于传统耕作,保护性耕作有利于土壤有机碳、水分利用效率和作物产量的提高,其中在“深松+秸秆还田”耕作模式下的增幅最高,土壤有机碳含量在0～30 cm土层增幅达到19.5%,水分利用效率和作物产量提高了16.9%和20.5%,而免耕模式则有效提高了0～10 cm土层有机碳含量.在该地区土壤和气候条件下,深松结合秸秆粉碎还田是最理想的耕作模式,最有利于土壤有机碳累积,并提高水分利用效率和作物产量.     

Immunohistochemical identification of aquaporin 2 in the kidneys of young beef cattle

Aquaporin 2 (AQP2) is a small, integral tetrameric plasma membrane protein that is expressed in mammalian kidneys. The specific constitution of this protein and its selective permeability to water means that AQP2 plays an important role in hypertonic urine production. Immunolocalization of AQP2 has been studied in humans, monkeys, sheep, dogs, rabbits, rats, mice and adult cattle. We analyzed the expression of AQP2 in kidneys of 7-month-old Polish-Friesian var. black and white male calves. AQP2 was localized in the principal cells of collecting ducts in medullary rays penetrating the renal cortex and in the collecting ducts of renal medulla. AQP2 was expressed most strongly in the apical plasma membrane, but expression was observed also in the intracellular vesicles and basolateral plasma membrane. Our study provides new information concerning the immunolocalization of AQP2 in calf kidneys.