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Available Sequences (available + sequence)
Selected AbstractsHigh local and global diversity of Flavobacteria in marine planktonENVIRONMENTAL MICROBIOLOGY, Issue 5 2007Cecilia Alonso Summary Members of the phylum Bacteroidetes are among the most abundant microbes in coastal marine waters, but it is unclear to which extent the diversity within this phylum is covered by currently available 16S rRNA gene sequence information. We, thus, obtained a comprehensive collection of sequence types affiliated with Bacteroidetes in coastal North Sea surface waters and we compared this local diversity with the available sequences of marine planktonic and other aquatic Bacteroidetes. Approximately 15% of > 600 clones from two libraries (August 2000, June 2001) were related to Bacteroidetes, specifically to the Flavobacteria. Local diversity appeared to be almost exhaustively sampled. However, the diversity of the two libraries virtually did not overlap, indicating a pronounced temporal variability of the planktonic Flavobacteria assemblage. The majority of sequence types represented novel phylogenetic lineages, adding 6,7% to the currently known genera and species of Bacteroidetes in marine waters. Different diversity estimators suggested that so far only approximately half of the global diversity of planktonic marine Bacteroidetes has been described. The data set moreover indicated that cultivation-independent techniques and isolation approaches have recovered almost equally sized and virtually non-overlapping fractions of the currently known diversity within this phylum. Interestingly, only 15% of genera of Bacteroidetes from various aquatic environments appear to occur in more than one habitat type. [source] Biological and Molecular Variability of Zucchini yellow mosaic virus in Iran,JOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2008Kaveh Bananej Abstract Zucchini yellow mosaic virus (ZYMV; family Potyviridae, genus Potyvirus) causes high yield losses to cucurbits in many parts of the world. The virus was detected for the first time in Iran in 1988, but the isolates have not been characterized. To study the genetic and biological diversity among Iranian ZYMV isolates, a set of twelve isolates, obtained during an extensive survey conducted from 2003 to 2006 in the major cucurbit-growing areas, were characterized. An experimental host range study of these isolates (referred as Iran-1 to Iran-12) revealed some variation in their biological properties. The nucleotide sequences of the genomic portion spanning the C-terminal part of NIb and N-terminal part of coat protein (CP) coding region were determined and compared with other available sequences. The identity among Iranian ZYMV isolates at the amino acid level reached 95.6,100%. The Iranian ZYMV isolates did not form a compact cluster in the phylogenetic tree, and the phylogenetic analyses and the estimation of genetic distance indicate that the Iranian ZYMV group consists of several independent introductions that evolved separately. [source] Molecular Analysis of Zucchini yellow mosaic virus Isolates from Hangzhou, ChinaJOURNAL OF PHYTOPATHOLOGY, Issue 6 2003M.-F. Zhao Abstract Isolates of Zucchini yellow mosaic virus were obtained from different cucurbit crops in Hangzhou city, China. The complete nucleotide sequences of four isolates and the 3,-terminal sequences, including the coat protein coding region, of four others were determined and then compared with other available sequences. Phylogenetic analysis of the coat protein nucleotide sequences showed that these isolates fell into three significant groups, one of which (designated group III) consisted exclusively of Chinese isolates and is reported for the first time. Comparisons over the completely sequenced genomes showed that, typically for potyviruses, the 5,-end of the genome was usually the most variable but that the group III isolate differed from the others most significantly in the N-terminal part of the coat protein. Partially sequenced group III isolates also varied from other isolates in this region. Group III isolates appear to differ biologically from the other isolates because they do not cause symptoms in watermelon fruit but induce more severe symptoms on the watermelon leaves. [source] The ankyrin repeat as molecular architecture for protein recognitionPROTEIN SCIENCE, Issue 6 2004Leila K. Mosavi Abstract The ankyrin repeat is one of the most frequently observed amino acid motifs in protein databases. This protein,protein interaction module is involved in a diverse set of cellular functions, and consequently, defects in ankyrin repeat proteins have been found in a number of human diseases. Recent biophysical, crystallographic, and NMR studies have been used to measure the stability and define the various topological features of this motif in an effort to understand the structural basis of ankyrin repeat-mediated protein,protein interactions. Characterization of the folding and assembly pathways suggests that ankyrin repeat domains generally undergo a two-state folding transition despite their modular structure. Also, the large number of available sequences has allowed the ankyrin repeat to be used as a template for consensus-based protein design. Such projects have been successful in revealing positions responsible for structure and function in the ankyrin repeat as well as creating a potential universal scaffold for molecular recognition. [source] Gene activation cascade triggered by a single photoperiodic cycle inducing flowering in Sinapis albaTHE PLANT JOURNAL, Issue 6 2009Maria D'Aloia Summary Molecular genetic analyses in Arabidopsis disclosed a genetic pathway whereby flowering is induced by the photoperiod. This cascade is examined here within the time course of floral transition in the long-day (LD) plant Sinapis alba induced by a single photoperiodic cycle. In addition to previously available sequences, the cloning of CONSTANS (SaCO) and FLOWERING LOCUS T (SaFT) homologues allowed expression analyses to be performed to follow the flowering process step by step. A diurnal rhythm in SaCO expression in the leaves was observed and transcripts of SaFT were detected when light was given in phase with SaCO kinetics only. This occurred when day length was extended or when a short day was shifted towards a ,photophile phase'. The steady-state level of SaFT transcripts in the various physiological situations examined was found to correlate like a rheostat with floral induction strength. Kinetics of SaFT activation were also consistent with previous estimations of translocation of florigen out of leaves, which could actually occur after the inductive cycle. In response to one 22-h LD, initiation of floral meristems by the shoot apical meristem (SAM) started about 2 days after activation of SaFT and was marked by expression of APETALA1 (SaAP1). Meanwhile, LEAFY (SaLFY) was first up-regulated in leaf primordia and in the SAM. FRUITFULL (SaFUL) was later activated in the whole SAM but excluded from floral meristems. These patterns are integrated with previous observations concerning upregulation of SUPPRESSOR OF OVEREXPRESSION OF CO1 (SaSOC1) to provide a temporal and spatial map of floral transition in Sinapis. [source] Structure of uracil-DNA glycosylase from Mycobacterium tuberculosis: insights into interactions with ligandsACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 8 2010Prem Singh Kaushal Uracil N -glycosylase (Ung) is the most thoroughly studied of the group of uracil DNA-glycosylase (UDG) enzymes that catalyse the first step in the uracil excision-repair pathway. The overall structure of the enzyme from Mycobacterium tuberculosis is essentially the same as that of the enzyme from other sources. However, differences exist in the N- and C-terminal stretches and some catalytic loops. Comparison with appropriate structures indicate that the two-domain enzyme closes slightly when binding to DNA, while it opens slightly when binding to the proteinaceous inhibitor Ugi. The structural changes in the catalytic loops on complexation reflect the special features of their structure in the mycobacterial protein. A comparative analysis of available sequences of the enzyme from different sources indicates high conservation of amino-acid residues in the catalytic loops. The uracil-binding pocket in the structure is occupied by a citrate ion. The interactions of the citrate ion with the protein mimic those of uracil, in addition to providing insights into other possible interactions that inhibitors could be involved in. [source] | |||||||||||||