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991.
992.
Pyrosequencing-derived bacterial, archaeal, and fungal diversity of spacecraft hardware destined for Mars 总被引:2,自引:0,他引:2
La Duc MT Vaishampayan P Nilsson HR Torok T Venkateswaran K 《Applied and environmental microbiology》2012,78(16):5912-5922
Spacecraft hardware and assembly cleanroom surfaces (233 m(2) in total) were sampled, total genomic DNA was extracted, hypervariable regions of the 16S rRNA gene (bacteria and archaea) and ribosomal internal transcribed spacer (ITS) region (fungi) were subjected to 454 tag-encoded pyrosequencing PCR amplification, and 203,852 resulting high-quality sequences were analyzed. Bioinformatic analyses revealed correlations between operational taxonomic unit (OTU) abundance and certain sample characteristics, such as source (cleanroom floor, ground support equipment [GSE], or spacecraft hardware), cleaning regimen applied, and location about the facility or spacecraft. National Aeronautics and Space Administration (NASA) cleanroom floor and GSE surfaces gave rise to a larger number of diverse bacterial communities (619 OTU; 20 m(2)) than colocated spacecraft hardware (187 OTU; 162 m(2)). In contrast to the results of bacterial pyrosequencing, where at least some sequences were generated from each of the 31 sample sets examined, only 13 and 18 of these sample sets gave rise to archaeal and fungal sequences, respectively. As was the case for bacteria, the abundance of fungal OTU in the GSE surface samples dramatically diminished (9× less) once cleaning protocols had been applied. The presence of OTU representative of actinobacteria, deinococci, acidobacteria, firmicutes, and proteobacteria on spacecraft surfaces suggests that certain bacterial lineages persist even following rigorous quality control and cleaning practices. The majority of bacterial OTU observed as being recurrent belonged to actinobacteria and alphaproteobacteria, supporting the hypothesis that the measures of cleanliness exerted in spacecraft assembly cleanrooms (SAC) inadvertently select for the organisms which are the most fit to survive long journeys in space. 相似文献
993.
Cleber Witt Saldanha Caio Gomide Otoni Jéssica Laísca Fernanda de Azevedo Leonardo Lucas Carnevalli Dias Mailson Monteiro do Rêgo Wagner Campos Otoni 《Plant Cell, Tissue and Organ Culture》2012,110(3):413-422
In vitro propagated plants under conditions of low gas exchange generally show morphological and physiological anomalies that lead to high mortality rates during ex vitro acclimatization. The use of gas-permeable membranes increases natural ventilation in culture vessels, photosynthesis and growth rates. However, commercial membranes are expensive, which limits their application. In this study, low-cost, simple to manufacture, alternative membranes were developed to promote gas exchange in jars used for in vitro plant tissue culture. The membranes were developed using polytetrafluoroethylene film and two or three layers of microporous tape (Missner & Missner?), and were designed to increase the growth of nodal cultures of Pfaffia glomerata (Brazilian ginseng). Conditions that provided higher gas exchange led to an increase in plant growth and content of photosynthetic pigments compared to a closed system without a gas-permeable membrane. The alternative membranes showed similar results for water vapor loss rate and photosynthetic pigments when compared to a commercial membrane. The alternative membranes were also an efficient barrier against contamination and remained intact after being autoclaved multiple times. Among the membranes tested, the traits of the P. glomerata in vitro-derived plants were similar when propagated using the alternative membrane with three layers of microporous tape or the commercial membrane. However, the alternative membrane has a unit cost that is ten times lower than the commercial membrane. 相似文献
994.
Magazù S Migliardo F Benedetto A La Torre R Hennet L 《European biophysics journal : EBJ》2012,41(4):361-367
In this contribution the effects of the homologous disaccharides trehalose and sucrose on both water and hydrated lysozyme
dynamics are considered by determining the mean square displacement (MSD) from elastic incoherent neutron scattering (EINS)
experiments. The self-distribution function (SDF) procedure is applied to the data collected, by use of IN13 and IN10 spectrometers
(Institute Laue Langevin, France), on trehalose and sucrose aqueous mixtures (at a concentration corresponding to 19 water
molecules per disaccharide molecule), and on dry and hydrated (H2O and D2O) lysozyme also in the presence of the disaccharides. As a result, above the glass transition temperature of water, the MSD
of the water–trehalose system is lower than that of the water–sucrose system. This result suggests that the hydrogen-bond
network of the water–trehalose system is stronger than that of the water–sucrose system. Furthermore, by taking into account
instrumental resolution effects it was found that the system relaxation time of the water–trehalose system is longer than
that of the water–sucrose system, and the system relaxation time of the protein in a hydrated environment in the presence
of disaccharides increases sensitively. These results explain the higher bioprotectant effectiveness of trehalose. Finally,
the partial MSDs of sucrose/water and trehalose/water have been evaluated. It clearly emerges from the analysis that these
are almost equivalent in the low-Q domain (0–1.7 ?−1) but differ substantially in the high-Q range (1.7–4 ?−1). These findings reveal that the lower structural sensitivity of trehalose to thermal changes is connected with the local
spatial scale. 相似文献
995.
Trotta A Redondo-Gómez S Pagliano C Clemente ME Rascio N Rocca NL Antonacci A Andreucci F Barbato R 《Journal of plant physiology》2012,169(2):111-116
The effect of different external salt concentrations, from 0 mM to 1030 mM NaCl, on photosynthetic complexes and chloroplast ultrastructure in the halophyte Arthrocnemum macrostachyum was studied. Photosystem II, but not Photosystem I or cytochrome b6/f, was affected by salt treatment. We found that the PsbQ protein was never expressed, whereas the amounts of PsbP and PsbO were influenced by salt in a complex way. Analyses of Photosystem II intrinsic proteins showed an uneven degradation of subunits with a loss of about 50% of centres in the 0 mM NaCl treated sample. Also the shape of chloroplasts, as well as the organization of thylakoid membranes were affected by NaCl concentration, with many grana containing few thylakoids at 1030 mM NaCl and thicker grana and numerous swollen thylakoids at 0 mM NaCl. The PsbQ protein was found to be depleted also in thylakoids from other halophytes. 相似文献
996.
Kowalczewska M Vellaiswamy M Nappez C Vincentelli R Scola BL Raoult D 《FEMS immunology and medical microbiology》2012,64(1):130-133
The laboratory diagnosis of rickettsioses is based on serology (reference method), cell culture and/or molecular tools. However, the main drawback of serology is its incapacity to provide identification of Rickettsiae at the level of species. The aim of this study was to propose the versatile protein markers able to discriminate the patients with murine typhus from those with Mediterranean spotted fever. We have cloned and expressed 20 proteins of Rickettsia prowazekii and Rickettsia rickettsii, respectively, using the GATEWAY approach. These recombinant proteins were screened by ELISA with sera of infected patients with Rickettsia typhi and Rickettsia conorii, respectively. We identified several potential markers which allowed infection due to R.?typhi to be discriminated from those due to R.?conorii. However, the values of test-operating parameters were not sufficient for its 'routine' clinical use. Our diagnostic test requires further optimization for be applied as a point-of-care strategy in the management of patients with suspected cases of rickettsiosis. 相似文献
997.
Gentile A Antognoni F Iorio RA Distefano G Las Casas G La Malfa S Serafini-Fracassini D Del Duca S 《Amino acids》2012,42(2-3):1025-1035
Pollination of pummelo (Citrus grandis L. Osbeck) pistils has been studied in planta by adding compatible and self-incompatible (SI) pollen to the stigma surface. The pollen germination has been monitored inside the pistil by fluorescent microscopy showing SI altered morphologies with irregular depositions of callose in the tube walls, and heavy callose depositions in enlarged tips. The polyamine (PA) content as free, perchloric acid (PCA)-soluble and -insoluble fractions and transglutaminase (TGase) activity have been analyzed in order to deepen their possible involvement in the progamic phase of plant reproduction. The conjugated PAs in PCA-soluble fraction were definitely higher than the free and the PCA-insoluble forms, in both compatible and SI pollinated pistils. In pistils, pollination caused an early decrease of free PAs and increase of the bound forms. The SI pollination, showed highest values of PCA-soluble and -insoluble PAs with a maximum in concomitance with the pollen tube arrest. As TGase mediates some of the effects of PAs by covalently binding them to proteins, its activity, never checked before in Citrus, was examined with two different assays. In addition, the presence of glutamyl-PAs confirmed the enzyme assay data and excluded the possibility of a misinterpretation. The SI pollination caused an increase in TGase activity, whereas the compatible pollination caused its decrease. Similarly to bound PAs, the glutamyl-PAs and the enzyme activity peaked in the SI pollinated pistils in concomitance with the observed block of the pollen tube growth, suggesting an involvement of TGase in SI response. 相似文献
998.
L Albuquerque M Taborda V La Cono M Yakimov MS da Costa 《Systematic and applied microbiology》2012,35(6):368-373
Two halophilic archaea, strains MDB25(T) and MDB20, were isolated from a sample of the brine from Lake Medee, at a depth of 3050m, in the Mediterranean Sea. Cells of the organisms were Gram-negative, non-motile and pleomorphic, and colonies were red pigmented. Strains MDB25(T) and MDB20 showed optimum growth at 45°C, in 2.6-3.4M NaCl and at pH 7.0-8.0. The major polar lipids of the two strains were phosphatidylglycerol (PG1 and PG2), phosphatidylglycerol phosphate methyl ester (PGP-Me) and mannose-2,6-dissulfate (1→2)-glucose glycerol diether (S(2)-DGD). Menaquinone MK-8 and MK-8(H(2)) were the major respiratory quinones. The DNA G+C content of strain MDB25(T) was 63.0%. The strains were facultatively anaerobic but grew better under aerobic conditions, nitrate served as electron acceptor. Analysis of the almost complete 16S rRNA gene sequence indicated that the strains MDB25(T) and MDB20 represented a member of the genus Natrinema in the family Halobacteriaceae. Both strains formed a distinct cluster and were most closely related to Natrinema ejinorense JCM 13890(T) and Haloterrigena longa JCM 13562(T) (98.0% and 97.9% sequence similarity, respectively). Based on 16S rRNA gene sequence analysis, DNA-DNA hybridization results, physiological and biochemical characteristics we describe a new species represented by strain MDB25(T) (=DSM 25055(T) =JCM 17869(T)) for which we propose the name Natrinema salaciae sp. nov. 相似文献
999.
Reversible acetylation mediated by histone deacetylases (HDACs) influences a broad repertoire of physiological processes, many of which are aberrantly controlled in tumor cells. As HDAC inhibition prompts tumor cells to enter apoptosis, small-molecule HDAC inhibitors have been developed as a new class of mechanism-based anti-cancer agent, many of which have entered clinical trials. Although the clinical picture is evolving and the precise utility of HDAC inhibitors remains to be determined, it is noteworthy that certain tumor types undergo a favorable response, in particular hematological malignancies. Vorinostat and romidepsin have been approved for treating cutaneous T-cell lymphoma in patients with progressive, persistent or recurrent disease. Here, we discuss developments in our understanding of molecular events that underlie the anti-cancer effects of HDAC inhibitors and relate this information to the emerging clinical picture for the application of these inhibitors in the treatment of cancer. 相似文献
1000.
汉坦病毒(Hantavirus,HV)是肾综合症出血热(Hemorrhagic fever with renal syndrome,HFRS)的主要病原体之一,HV的主要宿主动物为黑线姬鼠(Apodemus agrarius).针对西安市HFRS的持续高发病率,2010年7月-9月对西安市HFRS 疫区捕获的110只黑线姬鼠(阳性62只)进行年龄、性别鉴定.通过病毒RNA提取分析,发现黑线姬鼠雌雄个体携带病毒无显著差异,但是不同年龄段黑线姬鼠携带汉坦病毒却具有显著差异,年龄结构与病毒携带具有极显著的相关性. 相似文献