Streptomyces deserti sp. nov., isolated from hyper-arid Atacama Desert soil

The taxonomic position of a Streptomyces strain isolated from a hyper-arid desert soil was established using a polyphasic approach. The organism had chemical and morphological properties typical of the genus Streptomyces and formed a phyletic line at the periphery of the Streptomyces coeruleorubidus subcluster in the 16S rRNA gene tree. DNA:DNA relatedness values between the isolate and its nearest phylogenetic neighbours, Streptomyces lomondensis NRRL 3252^T and Streptomyces lusitanus NRRL B-12501^T were 42.5 (±0.48)% and 25.0 (±1.78)%, respectively. The isolate was readily distinguished from these organisms using a combination of morphological and phenotypic properties. On the basis of these results, it is proposed that isolate C63^T (CGMCC 4.6997^T, = KACC 15425^T) be classified as the type strain of Streptomyces deserti sp. nov.     

Structure, diversity, and mobility of the Salmonella pathogenicity island 7 family of integrative and conjugative elements within Enterobacteriaceae

Integrative and conjugative elements (ICEs) are self-mobile genetic elements found in the genomes of some bacteria. These elements may confer a fitness advantage upon their host bacteria through the cargo genes that they carry. Salmonella pathogenicity island 7 (SPI-7), found within some pathogenic strains of Salmonella enterica, possesses features indicative of an ICE and carries genes implicated in virulence. We aimed to identify and fully analyze ICEs related to SPI-7 within the genus Salmonella and other Enterobacteriaceae. We report the sequence of two novel SPI-7-like elements, found within strains of Salmonella bongori, which share 97% nucleotide identity over conserved regions with SPI-7 and with each other. Although SPI-7 within Salmonella enterica serovar Typhi appears to be fixed within the chromosome, we present evidence that these novel elements are capable of excision and self-mobility. Phylogenetic analyses show that these Salmonella mobile elements share an ancestor which existed approximately 3.6 to 15.8 million years ago. Additionally, we identified more distantly related ICEs, with distinct cargo regions, within other strains of Salmonella as well as within Citrobacter, Erwinia, Escherichia, Photorhabdus, and Yersinia species. In total, we report on a collection of 17 SPI-7 related ICEs within enterobacterial species, of which six are novel. Using comparative and mutational studies, we have defined a core of 27 genes essential for conjugation. We present a growing family of SPI-7-related ICEs whose mobility, abundance, and cargo variability indicate that these elements may have had a large impact on the evolution of the Enterobacteriaceae.     

Genomic characterization of natural and somaclonal variations in bananas (<Emphasis Type="Italic">Musa</Emphasis> spp.)

Unexpected variations can occur during natural and in vitro propagation of bananas (banana and plantain) to generate off-types. The molecular basis of such variations is not well-understood. This study aimed to characterize the functions of genomic regions varying within clones grown naturally or in vitro. Fifty-four simple sequence repeat (SSR) markers and six primer combinations of EcoR I/Msp I-amplified fragment length polymorphism (AFLP) were used to analyze accessions of the AA, BB, AB, AAA, AAB, and ABB groups of Musa, and polymorphic regions were sequenced to characterize candidate genes. One SSR locus with significant similarity to an arcelin gene revealed a deletion in a subculture regenerant. In AFLP analysis, 24 (6.15%) of 390 bands accounted for within-clone variations, with 0.5% and 5.65% occurring in natural and in vitro propagated plants, respectively. Sequence homology searches revealed that most polymorphic regions were related to cytochrome P450, cell-wall biosynthesis, and senescence genes. The importance of these candidate genes is discussed. The plants harboring the variations were field-established to relate molecular variations to phenotypic changes. Sixteen of the sequences registered in Genbank (ET165586 to ET165601) and select PCR primers from this study can be further tested for variations between normal clones and off-types in Musa.     

Mucuna pruriens Linn. seed extract pretreatment protects against cardiorespiratory and neuromuscular depressant effects of Naja sputatrix (Javan spitting cobra) venom in rats

Mucuna pruriens has been used by native Nigerians as a prophylactic for snakebite. The protective effects of M. pruriens seed extract (MPE) were investigated against the pharmacological actions of N. sputatrix (Javan spitting cobra) venom in rats. The results showed that MPE-pretreatment protected against cardiorespiratory and, to a lesser extent, neuromuscular depressant effects of N. sputatrix venom. These may be explained at least in part by the neutralisation of the cobra venom toxins by anti-MPE antibodies elicited by the MPE pretreatment.     

Signatures of Adaptation in Human Invasive Salmonella Typhimurium ST313 Populations from Sub-Saharan Africa

Two lineages of Salmonella enterica serovar Typhimurium (S. Typhimurium) of multi-locus sequence type ST313 have been linked with the emergence of invasive Salmonella disease across sub-Saharan Africa. The expansion of these lineages has a temporal association with the HIV pandemic and antibiotic usage. We analysed the whole genome sequence of 129 ST313 isolates representative of the two lineages and found evidence of lineage-specific genome degradation, with some similarities to that observed in S. Typhi. Individual ST313 S. Typhimurium isolates exhibit a distinct metabolic signature and modified enteropathogenesis in both a murine and cattle model of colitis, compared to S. Typhimurium outside of the ST313 lineages. These data define phenotypes that distinguish ST313 isolates from other S. Typhimurium and may represent adaptation to a distinct pathogenesis and lifestyle linked to an-immuno-compromised human population.     

Characterization of Conformation-Sensitive Antibodies to ADAMTS13, the von Willebrand Cleavage Protease

Background

The zinc metalloprotease ADAMTS13 is a multidomain protein that cleaves von Willebrand Factor (VWF) and is implicated in Thrombotic Thrombocytopenic Purpura (TTP) pathogenesis. Understanding the mechanism of this protein is an important goal. Conformation sensitive antibodies have been used to monitor protein conformation and to decipher the molecular mechanism of proteins as well as to distinguish functional and non-functional mutants.

Methodology/Principal Findings

We have characterized several antibodies against ADAMTS13, both monoclonal and polyclonal. We have used flow cytometry to estimate the binding of these antibodies to ADAMTS13 and demonstrate that antibodies raised against the TSP and disintegrin domains detect conformation changes in the ADAMTS13. Thus for example, increased binding of these antibodies was detected in the presence of the substrate (VWF), mainly at 37°C and not at 4°C. These antibodies could also detect differences between wild-type ADAMTS13 and the catalytically deficient mutant (P475S). The flow cytometry approach also allows us to estimate the reactivity of the antibody as well as its apparent affinity.

Conclusions/Significance

Our results suggest that these antibodies may serve as useful reagents to distinguish functional and non-functional ADAMTS13 and analyze conformational transitions to understand the catalytic mechanism.     

Aspergillus nidulans Synthesize Insect Juvenile Hormones upon Expression of a Heterologous Regulatory Protein and in Response to Grazing by Drosophila melanogaster Larvae

Secondary metabolites are known to serve a wide range of specialized functions including communication, developmental control and defense. Genome sequencing of several fungal model species revealed that the majority of predicted secondary metabolite related genes are silent in laboratory strains, indicating that fungal secondary metabolites remain an underexplored resource of bioactive molecules. In this study, we combine heterologous expression of regulatory proteins in Aspergillus nidulans with systematic variation of growth conditions and observe induced synthesis of insect juvenile hormone-III and methyl farnesoate. Both compounds are sesquiterpenes belonging to the juvenile hormone class. Juvenile hormones regulate developmental and metabolic processes in insects and crustaceans, but have not previously been reported as fungal metabolites. We found that feeding by Drosophila melanogaster larvae induced synthesis of juvenile hormone in A. nidulans indicating a possible role of juvenile hormone biosynthesis in affecting fungal-insect antagonisms.     

Stemming the tide of centrifugal forces in Igbo orthography

The paper deplores the increasing practice whereby individuals and groups write Igbo with orthographic conventions that deviate from those of the official Igbo (Ọnwụ) Orthography. It warns that these divergent acts are steadily dragging Igbo Orthography into a state of anarchy whose consequences could be more disastrous than those of the earlier orthography controversy of 1929–1961. The paper briefly traces the history of Igbo orthography from the earliest mention of Igbo in the sixteenth century writings of European travelers to the present times. Among its recommendations for the restoration of sanity in Igbo orthography are: the respect of the present official one until new conventions are officially agreed to and sanctioned; the revival of the Igbo Standardization Committee which formerly regulated and supervised developments in the language; the convening of an international workshop on Igbo orthography and the production of an enlarged Pan Igbo orthography for writing in dialects while the present official (Ọnwụ) orthography serves for Standard Igbo.