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Publication
Journal: Applied and Environmental Microbiology
June/24/2010
Abstract
Microelectrodes were used to measure oxygen, pH, and oxygenic photosynthetic activity in a hot spring microbial mat (Octopus Spring, Yellowstone National Park), where the cyanobacterium Synechococcus lividus and the filamentous bacterium Chloroflexus aurantiacus are the only known phototrophs. The data showed very high biological activities in the topmost layers of the microbial mat, resulting in extreme values for oxygen and pH. At a 1-mm depth at a 55 degrees C site, oxygen and pH reached 900 muM and 9.4, respectively, just after solar noon, whereas anoxic conditions with a pH of 7.2 were measured before sunrise. Although diurnal changes between these extremes occurred over hours during a diurnal cycle, microbial activity was great enough to give the same response in 1 to 2 min after artificial shading. Oxygenic photosynthesis was confined to a 0.5- to 1.1-mm layer at sites with temperatures at or above about 50 degrees C, with maximum activities in the 55 to 60 degrees C region. The data suggest that S. lividus is the dominant primary producer of the mat.
Publication
Journal: International journal of systematic bacteriology
September/28/1994
Abstract
We analyzed the 16S ribosomal DNAs of three obligately aerobic, bacteriochlorophyll a-containing bacteria, "Roseococcus thiosulfatophilus," "Erythromicrobium ramosum," and new isolate T4T (T = type strain), which was obtained from a marine cyanobacterial mat. "Roseococcus thiosulfatophilus" is a member of the alpha-1 subclass of the Proteobacteria and is moderately related to Rhodopila globiformis, Thiobacillus acidophilus, and Acidiphilium cryptum (level of sequence similarity, 90%). "Erythromicrobium ramosum" and isolate T4T are closely related to Erythrobacter longus and Porphyrobacter neustonensis (level of sequence similarity, 95%). These organisms are members of the alpha-4 subclass of the Proteobacteria. Strain T4T is a motile, red or orange bacterium. The major carotenoids are bacteriorubixanthinal and erythroxanthin sulfate. In vivo measurements revealed bacteriochlorophyll absorption maxima at 377, 590, 800, and 868 nm. Strain T4T grows in the presence of 5 to 96/1000 salinity and uses glucose, fructose, acetate, pyruvate, glutamate, succinate, and lactate as substrates. On the basis of its distinct phylogenetic position and phenotypic characteristics which are different from those of Erythrobacter longus, we propose that strain T4T should be placed in a new species of the genus Erythrobacter, Erythrobacter litoralis. The descriptions of "Roseococcus thiosulfatophilus" and "Erythromicrobium ramosum" are emended.
Publication
Journal: International Journal of Epidemiology
July/28/1999
Abstract
BACKGROUND
In Western countries, leptospirosis is uncommon and mainly occurs in farmers and individuals indulging in water-related activities. In tropical countries, leptospirosis can be up to 1000 times more frequent and risk factors for this often severe disease may differ.
METHODS
We conducted a one-year population-based matched case-control study to investigate the frequency and associated factors of leptospirosis in the entire population of Seychelles.
RESULTS
A total of 75 patients had definite acute leptospirosis based on microagglutination test (MAT) and polymerase chain reaction (PCR) assay (incidence: 101 per 100,000 per year; 95% confidence interval [CI]: 79-126). Among the controls, MAT was positive in 37% (past infection) and PCR assay in 9% (subclinical infection) of men aged 25-64 with manual occupation. Comparing cases and controls with negative MAT and PCR, leptospirosis was associated positively with walking barefoot around the home, washing in streams, gardening, activities in forests, alcohol consumption, rainfall, wet soil around the home, refuse around the home, rats visible around the home during day time, cats in the home, skin wounds and inversely with indoor occupation. The considered factors accounted for as much as 57% of the variance in predicting the disease.
CONCLUSIONS
These data indicate a high incidence of leptospirosis in Seychelles. This suggests that leptospires are likely to be ubiquitous and that effective leptospirosis control in tropical countries needs a multifactorial approach including major behaviour change by large segments of the general public.
Publication
Journal: PLoS ONE
August/1/2011
Abstract
BACKGROUND
Rapid PCR-based tests for the diagnosis of leptospirosis can provide information that contributes towards early patient management, but these have not been adopted in Thailand. Here, we compare the diagnostic sensitivity and specificity of two real-time PCR assays targeting rrs or lipL32 for the diagnosis of leptospirosis in northeast Thailand.
RESULTS
A case-control study of 266 patients (133 cases of leptospirosis and 133 controls) was constructed to evaluate the diagnostic sensitivity and specificity (DSe & DSp) of both PCR assays. The median duration of illness prior to admission of cases was 4 days (IQR 2-5 days; range 1-12 days). DSe and DSp were determined using positive culture and/or microscopic agglutination test (MAT) as the gold standard. The DSe was higher for the rrs assay than the lipL32 assay (56%, (95% CI 47-64%) versus 43%, (95% CI 34-52%), p<0.001). No cases were positive for the lipL32 assay alone. There was borderline evidence to suggest that the DSp of the rrs assay was lower than the lipL32 assay (90% (95% CI 83-94%) versus 93%, (95%CI 88-97%), p = 0.06). Nine controls gave positive reactions for both assays and 5 controls gave a positive reaction for the rrs assay alone. The DSe of the rrs and lipL32 assays were high in the subgroup of 39 patients who were culture positive for Leptospira spp. (95% and 87%, respectively, p = 0.25).
CONCLUSIONS
Early detection of Leptospira using PCR is possible for more than half of patients presenting with leptospirosis and could contribute to individual patient care.
Publication
Journal: Acta Biomaterialia
November/4/2009
Abstract
Materials able to deliver topically bioactive molecules represent a new generation of biomaterials. In this article, we describe the use of silk mats, made of electrospun nanoscale silk fibers containing epidermal growth factor (EGF), for the promotion of wound healing processes. In our experiments, we demonstrated that EGF is incorporated into the silk mats and slowly released in a time-dependent manner (25% EGF release in 170h). We tested these materials using a new model of wounded human skin-equivalents displaying the same structure as human skin and able to heal using the same molecular and cellular mechanisms found in vivo. This human three-dimensional model allows us to demonstrate that the biofunctionalized silk mats, when placed on the wounds as a dressing, aid the healing by increasing the time of wound closure by the epidermal tongue by 90%. The preservation of the structure of the mats during the healing period as demonstrated by electronic microscopy, the biological action of the dressing, as well as the biocompatibility of the silk demonstrate that this biomaterial is a new and very promising material for medical applications, especially for patients suffering from chronic wounds.
Publication
Journal: Eukaryotic cell
January/30/2007
Abstract
Nonself recognition during somatic growth is an essential and ubiquitous phenomenon in both prokaryotic and eukaryotic species. In filamentous fungi, nonself recognition is also important during vegetative growth. Hyphal fusion between genetically dissimilar individuals results in rejection of heterokaryon formation and in programmed cell death of the fusion compartment. In filamentous fungi, such as Neurospora crassa, nonself recognition and heterokaryon incompatibility (HI) are regulated by genetic differences at het loci. In N. crassa, mutations at the vib-1 locus suppress nonself recognition and HI mediated by genetic differences at het-c/pin-c, mat, and un-24/het-6. vib-1 is a homolog of Saccharomyces cerevisiae NDT80, which is a transcriptional activator of genes during meiosis. For this study, we determined that vib-1 encodes a nuclear protein and showed that VIB-1 localization varies during asexual reproduction and during HI. vib-1 is required for the expression of genes involved in nonself recognition and HI, including pin-c, tol, and het-6; all of these genes encode proteins containing a HET domain. vib-1 is also required for the production of downstream effectors associated with HI, including the production of extracellular proteases upon carbon and nitrogen starvation. Our data support a model in which mechanisms associated with starvation and nonself recognition/HI are interconnected. VIB-1 is a major regulator of responses to nitrogen and carbon starvation and is essential for the expression of genes involved in nonself recognition and death in N. crassa.
Publication
Journal: IEEE Transactions on Biomedical Engineering
November/4/2010
Abstract
Gait velocity has been shown to quantitatively estimate risk of future hospitalization, a predictor of disability, and has been shown to slow prior to cognitive decline. In this paper, we describe a system for continuous and unobtrusive in-home assessment of gait velocity, a critical metric of function. This system is based on estimating walking speed from noisy time and location data collected by a "sensor line" of restricted view passive infrared motion detectors. We demonstrate the validity of our system by comparing with measurements from the commercially available GAITRite walkway system gait mat. We present the data from 882 walks from 27 subjects walking at three different subject-paced speeds (encouraged to walk slowly, normal speed, or fast) in two directions through a sensor line. The experimental results show that the uncalibrated system accuracy (average error) of estimated velocity was 7.1 cm/s (SD = 11.3 cm/s), which improved to 1.1 cm/s (SD = 9.1 cm/s) after a simple calibration procedure. Based on the average measured walking speed of 102 cm/s, our system had an average error of less than 7% without calibration and 1.1% with calibration.
Publication
Journal: Applied and Environmental Microbiology
June/24/2010
Abstract
The fate of representative fermentation products (acetate, propionate, butyrate, lactate, and ethanol) in hot spring cyanobacterial mats was investigated. The major fate during incubations in the light was photoassimilation by filamentous bacteria resembling Chloroflexus aurantiacus. Some metabolism of all compounds occurred under dark aerobic conditions. Under dark anaerobic conditions, only lactate was oxidized extensively to carbon dioxide. Extended preincubation under dark anaerobic conditions did not enhance anaerobic catabolism of acetate, propionate, or ethanol. Acetogenesis of butyrate was suggested by the hydrogen sensitivity of butyrate conversion to acetate and by the enrichment of butyrate-degrading acetogenic bacteria. Accumulation of fermentation products which were not catabolized under dark anaerobic conditions revealed their importance. Acetate and propionate were the major fermentation products which accumulated in samples collected at temperatures ranging from 50 to 70 degrees C. Other organic acids and alcohols accumulated to a much lesser extent. Fermentation occurred mainly in the top 4 mm of the mat. Exposure to light decreased the accumulation of acetate and presumably of other fermentation products. The importance of interspecies hydrogen transfer was investigated by comparing fermentation product accumulation at a 65 degrees C site, with naturally high hydrogen levels, and a 55 degrees C site, where active methanogenesis prevented significant hydrogen accumulation. There was a greater relative accumulation of reduced products, notably ethanol, in the 65 degrees C mat.
Publication
Journal: ACS Applied Materials & Interfaces
December/13/2015
Abstract
Currently, combining biomaterial scaffolds with living stem cells for tissue regeneration is a main approach for tissue engineering. Mesenchymal stem cells (MSCs) are promising candidates for musculoskeletal tissue repair through differentiating into specific tissues, such as bone, muscle, and cartilage. Thus, successfully directing the fate of MSCs through factors and inducers would improve regeneration efficiency. Here, we report the fabrication of graphene oxide (GO)-doped poly(lactic-co-glycolic acid) (PLGA) nanofiber scaffolds via electrospinning technique for the enhancement of osteogenic differentiation of MSCs. GO-PLGA nanofibrous mats with three-dimensional porous structure and smooth surface can be readily produced via an electrospinning technique. GO plays two roles in the nanofibrous mats: first, it enhances the hydrophilic performance, and protein- and inducer-adsorption ability of the nanofibers. Second, the incorporated GO accelerates the human MSCs (hMSCs) adhesion and proliferation versus pure PLGA nanofiber and induces the osteogenic differentiation. The incorporating GO scaffold materials may find applications in tissue engineering and other fields.
Publication
Journal: Journal of general microbiology
November/23/1993
Abstract
The three different pore-forming RTX-toxins of Actinobacillus pleuropneumoniae are reviewed, and new and uniform designations for these toxins and their genes are proposed. The designation ApxI (for Actinobacillus pleuropneumoniae RTX-toxin I) is proposed for the RTX-toxin produced by the reference strains for serotypes 1, 5a, 5b, 9, 10 and 11, which was previously named haemolysin I (HlyI) or cytolysin I (ClyI). This protein is strongly haemolytic and shows strong cytotoxic activity towards pig alveolar macrophages and neutrophils; it has an apparent molecular mass in the range 105 to 110 kDa. The genes of the apxI operon will have the designations apxIC, apxIA, apxIB, and apxID for the activator, the structural gene and the two secretion genes respectively. The designation ApxII is proposed for the RTX-toxin which is produced by all serotype reference strains except serotype 10 and which was previously named App, HlyII, ClyII or Cyt. This protein is weakly haemolytic and moderately cytotoxic and has an apparent molecular mass between 103 and 105 kDa. The genes of the apxII operon will have the designations apxIIC for the activator gene and apxIIA for the structural toxin gene. In the apxII operon, no genes for secretion proteins have been found. Secretion of ApxII seems to occur via the products of the secretion genes apxIB and apxID of the apxI operon. The designation ApxIII is proposed for the nonhaemolytic RTX-toxin of the reference strains for serotypes 2, 3, 4, 6 and 8, which was previously named cytolysin III (ClyIII), pleurotoxin (Ptx), or macrophage toxin (Mat).(ABSTRACT TRUNCATED AT 250 WORDS)
Publication
Journal: Applied and Environmental Microbiology
June/23/2003
Abstract
For 30 years it has been assumed that a single species of cyanobacteria, Phormidium corallyticum, is the volumetrically dominant component of all cases of black band disease (BBD) in coral. Cyanobacterium-specific 16S rRNA gene primers and terminal restriction fragment length polymorphism analyses were used to determine the phylogenetic diversity of these BBD cyanobacteria on coral reefs in the Caribbean and Indo-Pacific Seas. These analyses indicate that the cyanobacteria that inhabit BBD bacterial mats collected from the Caribbean and Indo-Pacific Seas belong to at least three different taxa, despite the fact that the corals in each case exhibit similar signs and patterns of BBD mat development.
Publication
Journal: Molecular and Cellular Biology
July/26/1995
Abstract
Sporulation of the yeast Saccharomyces cerevisiae represents a simple developmental process in which the events of meiosis and spore wall formation are accompanied by the sequential activation of temporally distinct classes of genes. In this study, we have examined expression of the SPS4 gene, which belongs to a group of genes that is activated midway through sporulation. We mapped the upstream boundary of the regulatory region of SPS4 by monitoring the effect of sequential deletions of 5'-flanking sequence on expression of plasmid-borne versions of SPS4 introduced into a MATa/MAT alpha delta sps4/delta sps4 strain. This analysis indicated that the 5' boundary of the regulatory region was within 50 bp of the putative TATA box of the gene. By testing various oligonucleotides that spanned this boundary and the downstream sequence for their ability to activate expression of a heterologous promoter, we found that a 15-bp sequence sufficed to act as a sporulation-specific upstream activation sequence. This 15-bp fragment, designated UASSPS4, activated expression of a CYC1-lacZ reporter gene midway through sporulation and was equally active in both orientations. Extending the UAS fragment to include the adjacent 14-bp enhanced its activity 10-fold. We show that expression of SPS4 is regulated in a manner distinct from that of early meiotic genes: mutation of UME6 did not lead to vegetative expression of SPS4, and sporulation-specific expression was delayed by mutation of IME2. In vivo and in vitro assays suggested that a factor present in vegetative cells bind to the UASSPS4 element. We speculate that during sporulation this factor is modified to serve as an activator of the SPS4 gene or, alternatively, that it recruits an activator to the promoter.
Publication
Journal: Genes and Development
September/21/1995
Abstract
During mating-type gene switching in Saccharomyces cerevisiae, DNA at the MAT locus is replaced by sequences copied from one of two unexpressed donor loci, HML or HMR, located near the two ends of the same chromosome and>> or = 90 kb from MAT. MATa cells recombine nearly 90% of the time with HML, whereas MAT alpha cells select HMR. MATa donor preference was examined by deleting HML and inserting a donor at other chromosome III locations. MATa activated a large >> or = 40 kb) region near the left end of chromosome III, such that a donor placed at several sites within this domain was strongly preferred over HMR. When inserted outside of this domain, the donor was used equally with HMR. MATa donor preference for HML was abolished by the expression of the negative regulator, MAT alpha 2; however, HML regained its preferred status when the donor was unsilenced. Mating-type-dependent activation of the left end of the chromosome is also observed for other types of recombination that do not involve MAT switching. Spontaneous recombination between two leu2 alleles is 20-30 times higher in MATa than in MAT alpha when one of the leu2 alleles is inserted in place of HML. Transcription in this donor activation region is not affected by mating type. We conclude that MATa donor preference involves a mating-type-regulated change in the accessibility of a large chromosomal domain for recombination.
Authors
Publication
Journal: Science
July/1/2010
Abstract
Oceanic macroaggregates (marine snow and Rhizosolenia mats) sampled from the Sargasso Sea are associated with bacterial and protozoan populations up to four orders of magnitude greater than those present in samples from the surrounding water. Filamentous, curved, and spiral bacteria constituted a higher proportion of the bacteria associated with the particles than were found among bacteria in the surrounding water. Protozoan populations were dominated numerically by heterotrophic microflagellates, but ciliates and amoebas were also observed. Macroaggregates are highly enriched heterotrophic microenvironments in the oceans and may be significant for the cycling of particulate organic matter in planktonic food chains.
Publication
Journal: Molecular and Cellular Biology
March/3/1991
Abstract
The RAP1 gene of Saccharomyces cerevisiae encodes an abundant DNA-binding protein, also known as GRF1, TBA, or TUF, that binds to many sites in the yeast genome in vitro. These sites define a consensus sequence, [sequence: see text], and deletion analyses of genes that contain this sequence have implicated the involvement of RAP1 in numerous cellular processes, including gene activation and repression. The MAT alpha locus, required for determination of the alpha cell type in yeast cells, contains a RAP1 binding site; this site coincides with the MAT alpha upstream activating sequence (UAS) and is necessary for expression of the two genes encoded by the MAT alpha locus, MAT alpha 1 and MAT alpha 2. We show that the MAT alpha UAS is sufficient to activate transcription from a promoterless gene fusion of the yeast CYC1 upstream region and the lacZ gene. Constructs containing only the MAT alpha UAS generated elevated levels of beta-galactosidase activity which were indistinguishable from those of constructs containing the entire MAT alpha intergenic region. Further, the MAT alpha UAS has an intrinsic polarity of transcriptional activation; transcription of CYC1-lacZ was six- to sevenfold higher when the UAS was oriented in the direction normally associated with MAT alpha 2 transcription. Point mutations in the MAT alpha UAS that reduce MAT alpha expression three- to fivefold resulted in a bi-mating phenotype, while a mutation that reduced MAT alpha expression still further resulted in an a-mating phenotype. We isolated plasmids from a high-copy-number yeast library that suppressed the bi-mating defect of point mutations in the MAT alpha UAS, and the most effective dosage suppressor contained the gene encoding RAP1. A temperature-sensitive rap1 mutant bi-mates at the semipermissive temperature. Double mutants at rap1 and mat alpha mate exclusively as a cells, at all temperatures, and do not express detectable levels of MAT alpha RNA. These data provide evidence that the RAP1 gene product functions at the MAT alpha UAS in vivo.
Publication
Journal: Applied and Environmental Microbiology
February/15/2009
Abstract
Fumarolic activity supports the growth of mat-like photoautotrophic communities near the summit (at 6,051 m) of Socompa Volcano in the arid core of the Andes mountains. These communities are isolated within a barren, high-elevation landscape where sparse vascular plants extend to only 4,600 m. Here, we combine biogeochemical and molecular-phylogenetic approaches to characterize the bacterial and eucaryotic assemblages associated with fumarolic and nonfumarolic grounds on Socompa. Small-subunit rRNA genes were PCR amplified, cloned, and sequenced from two fumarolic soil samples and two reference soil samples, including the volcanic debris that covers most of the mountain. The nonfumarolic, dry, volcanic soil was similar in nutrient status to the most extreme Antarctic Dry Valley or Atacama Desert soils, hosted relatively limited microbial communities dominated by Actinobacteria and Fungi, and contained no photoautotrophs. In contrast, modest fumarolic inputs were associated with elevated soil moisture and nutrient levels, the presence of chlorophyll a, and (13)C-rich soil organic carbon. Moreover, this soil hosted diverse photoautotroph-dominated assemblages that contained novel lineages and exhibited structure and composition comparable to those of a wetland near the base of Socompa (3,661-m elevation). Fumarole-associated eucaryotes were particularly diverse, with an abundance of green algal lineages and a novel clade of microarthropods. Our data suggest that volcanic degassing of water and (13)C-rich CO(2) sustains fumarole-associated primary producers, leading to a complex microbial ecosystem within this otherwise barren landscape. Finally, we found that human activities have likely impacted the fumarolic soils and that fumarole-supported photoautotrophic communities may be exceptionally sensitive to anthropogenic disturbance.
Publication
Journal: Yeast
April/29/1991
Abstract
We report here the DNA sequence of a segment of chromosome III extending over 8.2 kb. The sequence was determined using the random clone strategy followed by oligonucleotide-directed sequencing. The segment contains five long open reading frames, YCR521, 522, 523, 524 and 526, with only short distances between them. YCR523 (333 codons) encodes a ribokinase, a new function for yeast. YCR526 originates inside the MAT cassette, which is in continuity with the present segment, and extends over 358 codons outside of MAT. YCR524 (923 codons) codes for a putative membrane protein. YCR521, 522 and 524, have each been disrupted by insertion of a URA3 cassette and are non-essential genes. An active ARS element is located within YCR523 or its vicinity.
Publication
Journal: Journal of Medical Microbiology
November/15/2004
Abstract
The search for novel antigens suitable for improved vaccines and diagnostic reagents against leptospirosis led to the identification of LigA and LigB. LigA and LigB expression were not detectable at the translation level but were detectable at the transcription level in leptospires grown in vitro. Lig genes were present in pathogenic serovars of Leptospira, but not in non-pathogenic Leptospira biflexa. The conserved and variable regions of LigA and LigB (Con, VarA and VarB) were cloned, expressed and purified as GST-fusion proteins. Purified recombinant LigA and LigB were evaluated for their diagnostic potential in a kinetic ELISA (KELA) using sera from vaccinated and microscopic agglutination test (MAT)-positive dogs. Sera from vaccinated dogs showed reactivity to whole-cell antigens of leptospires but did not show reactivity in the KELA assay with recombinant antigens, suggesting a lack of antibodies to Lig proteins in the vaccinated animals. The diagnostic potential of recombinant Lig antigens in the KELA assay was evaluated by using 67 serum samples with MAT>> or =1600, which showed reactivity of 76, 41 and 35% to rConA, rVarA and rVarB, respectively. These findings suggest that recombinant antigen to the conserved region of LigA and LigB can differentiate between vaccinated and naturally infected animals.
Publication
Journal: Molecular & general genetics : MGG
July/13/1992
Abstract
The two idiomorphic alleles called mat+ and mat-, which control the mating types in Podospora anserina, have been cloned. Mat+ and mat- encompass 3.8 kb and 4.7 kb respectively, of unrelated DNA sequences flanked by common sequences. Subcloning allowed the identification and localization in each locus of the gene that controls fertilization, probably by determining the mating type. The mat+ gene, called FPR1, encodes a protein with a potential DNA-binding HMG domain. The presence of this motif suggests that the FPR1 polypeptide may act as a transcriptional factor. The mat- gene called FMR1 encodes a protein containing a motif that is also found in proteins controlling mating functions in Saccharomyces cerevisiae and Neurospora crassa. The role of this motif has not yet been established. Unlike the mat+ locus, where the FPR1 gene seems to represent the major information, the mat- locus contains information necessary for the post-fertilization steps of the sexual cycle besides the FMR1 gene.
Publication
Journal: Cell
August/12/1991
Abstract
By searching for genes that behave like CDC25 of S. cerevisiae in their ability to counteract a dominant-negative RAS2 mutant in a wild-type RAS-dependent manner, we have isolated a CDC25-like homolog, BUD5. BUD5 is tightly linked to the MAT locus. Although overexpressed BUD5 cannot substitute for CDC25 function, we present evidence that its gene product can bind to the guanine nucleotide binding-deficient RAS2val19ala22 gene product and thereby counteract its dominant-negative effect. We propose that BUD5 is a member of a family of CDC25-related genes that encode activators of RAS and RAS-like proteins.
Publication
Journal: Applied and Environmental Microbiology
April/18/2012
Abstract
Polar and alpine microbial communities experience a variety of environmental stresses, including perennial cold and freezing; however, knowledge of genomic responses to such conditions is still rudimentary. We analyzed the metagenomes of cyanobacterial mats from Arctic and Antarctic ice shelves, using high-throughput pyrosequencing to test the hypotheses that consortia from these extreme polar habitats were similar in terms of major phyla and subphyla and consequently in their potential responses to environmental stresses. Statistical comparisons of the protein-coding genes showed similarities between the mats from the two poles, with the majority of genes derived from Proteobacteria and Cyanobacteria; however, the relative proportions differed, with cyanobacterial genes more prevalent in the Antarctic mat metagenome. Other differences included a higher representation of Actinobacteria and Alphaproteobacteria in the Arctic metagenomes, which may reflect the greater access to diasporas from both adjacent ice-free lands and the open ocean. Genes coding for functional responses to environmental stress (exopolysaccharides, cold shock proteins, and membrane modifications) were found in all of the metagenomes. However, in keeping with the greater exposure of the Arctic to long-range pollutants, sequences assigned to copper homeostasis genes were statistically (30%) more abundant in the Arctic samples. In contrast, more reads matching the sigma B genes were identified in the Antarctic mat, likely reflecting the more severe osmotic stress during freeze-up of the Antarctic ponds. This study underscores the presence of diverse mechanisms of adaptation to cold and other stresses in polar mats, consistent with the proportional representation of major bacterial groups.
Publication
Journal: Journal of Psychiatric Research
April/24/2011
Abstract
Brain-derived neurotrophic factor (BDNF) is a key factor in learning and memory. Altered BDNF-signalling is thought to contribute to the pathogenesis of schizophrenia (SZ) especially in relation to cognitive deficits. However, analysis of serum BDNF as a potential biomarker in schizophrenia has provided controversial data. We hypothesized that these confounding results might be due to a differential regulation of BDNF precursor pro-BDNF (32 KDa) and proteolytic products mature (mat-BDNF; 14 KDa), and truncated-BDNF (28 KDa). Accordingly, we investigated the serum abundance of these BDNF isoforms and its relationship with cognitive impairment in schizophrenia. Schizophrenia was diagnosed with PANSS test. Abbreviated cognitive assessment included tests for attention, perceptual-motor skills, processing speed and memory. Using an ELISA assay, we found a slight reduction in serum BDNF levels in SZ patients (n = 40) with respect to healthy controls (HC, n = 40; p = 0.018). Western-blot analysis revealed increased serum pro-BDNF and mat-BDNF and reduced truncated-BDNF (p < 0.001) in SZ with respect to HC. Patients with an increase in pro-BDNF (n = 15/40) or mat-BDNF (n = 9/40) higher than the HC mean + 2 Standard Deviations (SD) also had >2SD reduction of truncated-BDNF (n = 27/40). Reduced truncated-BDNF correlated significantly with higher positive and lower negative PANNS scores and a worst performance in all cognitive assays but not with antipsychotic type. Measurement of serum truncated-BDNF abundance predicted for high cognitive deficits with sensitivity = 67.5%, specificity = 97.5%, Negative Predictive Value = 75% and Positive Predictive Value = 96.4%. These results suggest deficiency in pro-BDNF processing as a possible biological mechanism underlying schizophrenia with cognitive impairment.
Publication
Journal: Archives of pediatrics & adolescent medicine
September/21/2011
Abstract
OBJECTIVE
To determine the relative effect of interactive digital exercise that features player movement (ie, exergames) on energy expenditure among children of various body mass indexes (BMIs; calculated as weight in kilograms divided by height in meters squared).
METHODS
Comparison study.
METHODS
GoKids Boston, a youth fitness research and training center located at University of Massachusetts, Boston.
METHODS
Thirty-nine boys and girls (mean [SD] age, 11.5 [2.0] years) recruited from local schools and after-school programs.
METHODS
Six forms of exergaming as well as treadmill walking.
METHODS
In addition to treadmill walking at 3 miles per hour (to convert miles to kilometers, multiply by 1.6), energy expenditure of the following exergames were examined: Dance Dance Revolution, LightSpace (Bug Invasion), Nintendo Wii (Boxing), Cybex Trazer (Goalie Wars), Sportwall, and Xavix (J-Mat). Energy expenditure was measured using the CosMed K4B2 portable metabolic cart.
RESULTS
All forms of interactive gaming evaluated in our study increased energy expenditure above rest, with no between-group differences among normal (BMI < 85th percentile) and "at-risk" or overweight (BMI ≥ 85th percentile) children (P ≥ .05). Walking at 3 miles per hour resulted in a mean (SD) metabolic equivalent task value of 4.9 (0.7), whereas the intensity of exergaming resulted in mean (SD) metabolic equivalent task values of 4.2 (1.6) for Wii, 5.4 (1.8) for Dance Dance Revolution, 6.4 (1.6) for LightSpace, 7.0 (1.8) for Xavix, 5.9 (1.5) for Cybex Trazer, and 7.1 (1.7) for Sportwall. Enjoyment of the games was generally high but was highest for children with BMIs in the highest percentiles.
CONCLUSIONS
All games used in our study elevated energy expenditure to moderate or vigorous intensity. Exergaming has the potential to increase physical activity and have a favorable influence on energy balance, and may be a viable alternative to traditional fitness activities for children of various BMI levels.
Publication
Journal: Laboratory Animals
January/10/2011
Abstract
Isoflurane is currently the most common volatile anaesthetic used in laboratory mice, whereas in human medicine the more modern sevoflurane is often used for inhalation anaesthesia. This study aimed to characterize and compare the clinical properties of both anaesthetics for inhalation anaesthesia in mice. In an approach mirroring routine laboratory conditions (spontaneous breathing, gas supply via nose mask, preventing hypothermia by a warming mat) a 50 min anaesthesia was performed. Anaesthetics were administered in oxygen as carrier gas at standardized dosages of 1.5 minimum alveolar concentrations, which was 2.8% for isoflurane and 4.9% for sevoflurane. Both induction and recovery from anaesthesia proceeded quickly, within 1-2 min. During anaesthesia, all reflex testing was negative and no serious impairment of vital functions was found; all animals survived. The most prominent side-effect during anaesthesia was respiratory depression with hypercapnia, acidosis and a marked decrease in respiration rate. Under anaesthesia, heart rate and core body temperature remained within the normal range, but were significantly increased for 12 h after anaesthesia. Locomotor activity, daily food and water consumption and body weight progression showed no abnormalities after anaesthesia. No significant difference was found between the two anaesthetics. In conclusion, isoflurane and sevoflurane provided an equally reliable anaesthesia in laboratory mice.
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