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Bramhachari PV Kishor PB Ramadevi R Kumar R Rao BR Dubey SK 《Journal of microbiology and biotechnology》2007,17(1):44-51
Marine bacterial strains were isolated from coastal regions of Goa and screened for the strains that produce the highest amount of mucous exopolysaccharide (EPS). Our screening resulted in the identification of the strain Vibrio furnissii VB0S3 (hereafter called VB0S3), as it produced the highest EPS in batch cultures during the late logarithmic growth phase. The isolate was identified as VB0S3 based on morphological and biochemical properties. Growth and EPS production were studied in mineral salts medium supplemented with NaCl (1.5%) and glucose (0.2%). The exopolymer was recovered from the culture supernatant by using three volumes of cold ethanol precipitation and dialysis procedure. Chemical analyses of EPS revealed that it is primarily composed of neutral sugars, uronic acids, and proteins. Fourier-transform infrared (FT-IR) spectroscopy revealed the presence of carboxyl, hydroxyl, and amide groups, which correspond to a typical heteropolymeric polysaccharide, and the EPS also possessed good emulsification activity. The gas chromatographic analysis of an alditol-acetate derivatized sample of EPS revealed that it was mainly composed of galactose and glucose. Minor components found were mannose, rhamnose, fucose, ribose, arabinose, and xylose. EPS was readily isolated from culture supernatants, which suggests that the EPS was a slime-like exopolysaccharide. This is the first report of exopolysaccharide characterization that describes the isolation and characterization of an EPS expressed by Vibrio furnissii strain VB0S3. The results of the study contribute significantly and go a long way towards an understanding of the correlation between growth and EPS production, chemical composition, and industrial applications of the exopolysaccharide in environmental biotechnology and bioremediation. 相似文献
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A microsatellite-based consensus linkage map for species of Eucalyptus and a novel set of 230 microsatellite markers for the genus 总被引:1,自引:0,他引:1
Rosana PV Brondani Emlyn R Williams Claudio Brondani Dario Grattapaglia 《BMC plant biology》2006,6(1):20-16
Background
Eucalypts are the most widely planted hardwood trees in the world occupying globally more than 18 million hectares as an important source of carbon neutral renewable energy and raw material for pulp, paper and solid wood. Quantitative Trait Loci (QTLs) in Eucalyptus have been localized on pedigree-specific RAPD or AFLP maps seriously limiting the value of such QTL mapping efforts for molecular breeding. The availability of a genus-wide genetic map with transferable microsatellite markers has become a must for the effective advancement of genomic undertakings. This report describes the development of a novel set of 230 EMBRA microsatellites, the construction of the first comprehensive microsatellite-based consensus linkage map for Eucalyptus and the consolidation of existing linkage information for other microsatellites and candidate genes mapped in other species of the genus. 相似文献4.
JB Parentes-Vieira PV Lopes-Costa CG Pires AR dos Santos JD Pereira-Filho BB da Silva 《International Seminars in Surgical Oncology : ISSO》2007,4(1):22
Background
The objective of this study was to evaluate angiogenesis according to CD34 antigen expression in estrogen receptor (ER)-positive and negative breast carcinomas.Methods
This study comprised 64 cases of infiltrating ductal carcinoma in postmenopausal women divided into two groups: Group A: ER-positive, n = 35; and Group B: ER-negative, n = 29. The anti-CD34 monoclonal antibody was used as a marker for endothelial cells. Microvessel count was carried out in 10 fields per slide using a 40× objective lens (magnification 400×). Statistical analysis of the data was performed using Student's t-test (p < 0.05).Results
The mean number of vessels stained with the anti-CD34 antibody in the estrogen receptor-positive and negative tumors was 23.51 ± 1.15 and 40.24 ± 0.42, respectively. The number of microvessels was significantly greater in the estrogen receptor-negative tumors (p < 0.001).Conclusion
ER-negative tumors have significantly greater CD34 antigen expression compared to ER-positive tumors.5.
AIMS: The aim of the study was to isolate and characterize exopolysaccharide (EPS) produced by Vibrio harveyi strain VB23. METHODS AND RESULTS: Growth and EPS production by V. harveyi strain VB23, was studied in mineral salts medium supplemented with NaCl (1.5%) and glucose (0.2%). The rate of EPS production in batch cultures was highest during the late log phase of growth when compared with stationary growth phase. The exopolymer was recovered from the culture supernatant by using a cold ethanol precipitation-dialysis procedure. Chemical analyses of EPS revealed that it is primarily composed of neutral sugars, uronic acids, proteins and sulfates. The purified EPS revealed prominent functional reactive groups, such as hydroxyl, carboxylic and amides, which correspond to a typical heteropolymeric polysaccharide and the EPS, also possessed good emulsification activity. The gas chromatographic analysis of an alditol acetate-derivatized sample of EPS revealed that it is composed primarily of galactose and glucose. Minor components found were rhamnose, fucose, ribose, arabinose, xylose and mannose. CONCLUSIONS: The EPS produced by V. harveyi strain VB23 is a heteropolysaccharide possessing good emulsification activity. EPS was readily isolated from culture supernatants, which suggests that the EPS was a slime-like EPS. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report of EPS characterization in luminous V. harveyi bacteria, which describes the isolation and characterization of an EPS expressed by V. harveyi. The results of the study contributes significantly towards an understanding of the chemical composition and applications of the EPS in environmental biotechnology and bioremediation. 相似文献
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Comparative analysis of the zeta-crystallin/quinone reductase gene in guinea pig and mouse 总被引:1,自引:0,他引:1
Gonzalez P; Hernandez-Calzadilla C; Rao PV; Rodriguez IR; Zigler JS Jr; Borras T 《Molecular biology and evolution》1994,11(2):305-315
zeta-Crystallin is a novel nicotinamide adenine dinucleotide
phosphate:quinone reductase, present at enzymatic levels in various tissues
of different species, which is highly expressed in the lens of some
hystricomorph rodents and camelids. We report here the complementary DNA
(cDNA) cloning of zeta-crystallin from liver libraries in guinea pig (Cavia
porcellus), where zeta-crystallin is highly expressed in the lens, and in
the laboratory mouse (Mus musculus), where expression in the lens occurs
only at enzymatic levels. A 5' untranslated sequence different from the one
previously reported for the guinea pig lens cDNA was found in these clones.
We also report the isolation of genomic clones including the complete
guinea pig zeta-crystallin gene and the 5' region of this gene in mouse.
These results show the presence of two promoters in the guinea pig
zeta-crystallin gene, one responsible for expression at enzymatic levels
and the other responsible for the high expression in the lens. The guinea
pig lens promoter is not present in the mouse gene. This is the first
example in which the recruitment of an enzyme as a lens crystallin can be
explained by the acquisition of an alternative lens- specific promoter.
相似文献
7.
IB Masters MM Eastburn PW Francis R Wootton PV Zimmerman RS Ware AB Chang 《Respiratory research》2005,6(1):16
Background
Flexible video bronchoscopes, in particular the Olympus BF Type 3C160, are commonly used in pediatric respiratory medicine. There is no data on the magnification and distortion effects of these bronchoscopes yet important clinical decisions are made from the images. The aim of this study was to systematically describe the magnification and distortion of flexible bronchoscope images taken at various distances from the object.Methods
Using images of known objects and processing these by digital video and computer programs both magnification and distortion scales were derived.Results
Magnification changes as a linear function between 100 mm (×1) and 10 mm (×9.55) and then as an exponential function between 10 mm and 3 mm (×40) from the object. Magnification depends on the axis of orientation of the object to the optic axis or geometrical axis of the bronchoscope. Magnification also varies across the field of view with the central magnification being 39% greater than at the periphery of the field of view at 15 mm from the object. However, in the paediatric situation the diameter of the orifices is usually less than 10 mm and thus this limits the exposure to these peripheral limits of magnification reduction. Intraclass correlations for measurements and repeatability studies between instruments are very high, r = 0.96. Distortion occurs as both barrel and geometric types but both types are heterogeneous across the field of view. Distortion of geometric type ranges up to 30% at 3 mm from the object but may be as low as 5% depending on the position of the object in relation to the optic axis.Conclusion
We conclude that the optimal working distance range is between 40 and 10 mm from the object. However the clinician should be cognisant of both variations in magnification and distortion in clinical judgements. 相似文献8.
McMillan DJ Kaul SY Bramhachari PV Smeesters PR Vu T Karmarkar MG Shaila MS Sriprakash KS 《PloS one》2011,6(8):e21346
Infection of the skin or throat by Streptococcus dysgalactiae subspecies equisimilis (SDSE) may result in a number of human diseases. To understand mechanisms that give rise to new genetic variants in this species, we used multi-locus sequence typing (MLST) to characterise relationships in the SDSE population from India, a country where streptococcal disease is endemic. The study revealed Indian SDSE isolates have sequence types (STs) predominantly different to those reported from other regions of the world. Emm-ST combinations in India are also largely unique. Split decomposition analysis, the presence of emm-types in unrelated clonal complexes, and analysis of phylogenetic trees based on concatenated sequences all reveal an extensive history of recombination within the population. The ratio of recombination to mutation (r/m) events (11:1) and per site r/m ratio (41:1) in this population is twice as high as reported for SDSE from non-endemic regions. Recombination involving the emm-gene is also more frequent than recombination involving housekeeping genes, consistent with diversification of M proteins offering selective advantages to the pathogen. Our data demonstrate that genetic recombination in endemic regions is more frequent than non-endemic regions, and gives rise to novel local SDSE variants, some of which may have increased fitness or pathogenic potential. 相似文献
9.
Evidence for independent recruitment of zeta-crystallin/quinone reductase (CRYZ) as a crystallin in camelids and hystricomorph rodents 总被引:3,自引:2,他引:1
Zeta-crystallin/quinone reductase (CRYZ) is an NADPH oxidoreductase
expressed at very high levels in the lenses of two groups of mammals:
camelids and some hystricomorph rodents. It is also expressed at very low
levels in all other species tested. Comparative analysis of the mechanisms
mediating the high expression of this enzyme/crystallin in the lens of the
Ilama (Lama guanacoe) and the guinea pig (Cavia porcellus) provided
evidence for independent recruitment of this enzyme as a lens crystallin in
both species and allowed us to elucidate for the first time the mechanism
of lens recruitment of an enzyme- crystallin. The data presented here show
that in both species such recruitment most likely occurred through the
generation of new lens promoters from nonfunctional intron sequences by the
accumulation of point mutations and/or small deletions and insertions.
These results further support the idea that recruitment of CRYZ resulted
from an adaptive process in which the high expression of CRYZ in the lens
provides some selective advantage rather than from a purely neutral
evolutionary process.
相似文献
10.
Carotenoids play a pivotal role in prevention of many degenerative diseases mediated by oxidative stress including neurodegenerative diseases like Alzheimer’s Disease (AD). The involvement of retinoids in physiology, AD pathology and their therapeutic role in vitro and in vivo has been extensively studied. This review focuses on the role of carotenoids like retinoic acid (RA), all trans retinoic acid (ATRA), lycopene and β-carotene in prevention of AD symptoms primarily through inhibition of amyloid beta (Aβ) formation, deposition and fibril formation either by reducing the levels of p35 or inhibiting corresponding enzymes. The role of antioxidant micronutrients in prevention or delaying of AD symptoms has been included. This study emphasizes the dietary supplementation of carotenoids to combat AD and warrants further studies on animal models to unravel their mechanism of neuroprotection. 相似文献