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1.
Virginia Edgcomb William Orsi John Bunge Sunok Jeon Richard Christen Chesley Leslin Mark Holder Gordon T Taylor Paula Suarez Ramon Varela Slava Epstein 《The ISME journal》2011,5(8):1344-1356
Microbial diversity and distribution are topics of intensive research. In two companion papers in this issue, we describe the results of the Cariaco Microbial Observatory (Caribbean Sea, Venezuela). The Basin contains the largest body of marine anoxic water, and presents an opportunity to study protistan communities across biogeochemical gradients. In the first paper, we survey 18S ribosomal RNA (rRNA) gene sequence diversity using both Sanger- and pyrosequencing-based approaches, employing multiple PCR primers, and state-of-the-art statistical analyses to estimate microbial richness missed by the survey. Sampling the Basin at three stations, in two seasons, and at four depths with distinct biogeochemical regimes, we obtained the largest, and arguably the least biased collection of over 6000 nearly full-length protistan rRNA gene sequences from a given oceanographic regime to date, and over 80 000 pyrosequencing tags. These represent all major and many minor protistan taxa, at frequencies globally similar between the two sequence collections. This large data set provided, via the recently developed parametric modeling, the first statistically sound prediction of the total size of protistan richness in a large and varied environment, such as the Cariaco Basin: over 36 000 species, defined as almost full-length 18S rRNA gene sequence clusters sharing over 99% sequence homology. This richness is a small fraction of the grand total of known protists (over 100 000–500 000 species), suggesting a degree of protistan endemism. 相似文献
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CD8 T cell-mediated killing of Cryptococcus neoformans requires granulysin and is dependent on CD4 T cells and IL-15 总被引:8,自引:0,他引:8
Ma LL Spurrell JC Wang JF Neely GG Epelman S Krensky AM Mody CH 《Journal of immunology (Baltimore, Md. : 1950)》2002,169(10):5787-5795
Granulysin is located in the acidic granules of cytotoxic T cells. Although the purified protein has antimicrobial activity against a broad spectrum of microbial pathogens, direct evidence for granulysin-mediated cytotoxicity has heretofore been lacking. Studies were performed to examine the regulation and activity of granulysin expressed by CD8 T cells using Cryptococcus neoformans, which is one of the most common opportunistic pathogens of AIDS patients. IL-15-activated CD8 T cells acquired anticryptococcal activity, which correlated with the up-regulation of granulysin. When granules containing granulysin were depleted using SrCl(2,) or when the gene was silenced using 21-nt small interfering RNA duplexes, the antifungal effect of CD8 T cells was abrogated. Concanamycin A and EGTA did not affect the antifungal effect, suggesting that the activity of granulysin was perforin independent. Following stimulation by the C. neoformans mitogen, CD8 T cells expressed granulysin and acquired antifungal activity. This activity required CD4 T cells and was dependent upon accessory cells. Furthermore, IL-15 was both necessary and sufficient for granulysin up-regulation in CD8 T cells. These observations are most consistent with a mechanism whereby C. neoformans mitogen is presented to CD4 T cells, which in turn activate accessory cells. The resultant IL-15 activates CD8 T cells to express granulysin, which is responsible for antifungal activity. 相似文献
3.
Slava S. Epstein Dennis A. Bazylinski William H. Fowle 《The Journal of eukaryotic microbiology》1998,45(1):64-70
ABSTRACT Bacterial epibionts were observed on the surface of the marine sediment ciliate Geleia fossata. Rod-shaped bacteria, from 2-10 X103 per ciliate, were universally positioned in ciliated grooves, in apparent spatial association with dikinetids. SEM and TEM examination of the ciliates confirmed that a tight affiliation exists between the epibiotic bacteria and ciliate cortex infrastructures. These observations, as well as the distinct bacterial distribution pattern over ciliate surface, suggest that there is a close epibiont/host physiological integration. Epibiotic bacteria were also observed on the surfaces of other sediment ciliates from the genera Loxophyllum, Tracheloraphis, Geleia, Paraspathidium , and Cyclidium. These findings indicate that the bacterial/protozoa associations are widespread in the marine benthic environment. The potential benefits for both epibionts and their hosts are discussed. 相似文献
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Abscisic acid stress ripening (ASR1) is a highly charged low molecular weight plant specific protein that is regulated by salt- and water-stresses. The protein possesses a zinc-dependent DNA-binding activity (Kalifa et al., Biochem. J. 381 (2004) 373) and overexpression in transgenic plants results in an increased salt-tolerance (Kalifa et al., Plant Cell Environ. 27 (2004) 1459). There are no structure homologs of ASR1, thus the structural and functional domains of the protein cannot be predicted. Here, we map the protein domains involved in the binding of Zn(2+) and DNA. Using mild acid hydrolysis, and a series of ASR1 carboxy-terminal truncations we show that the zinc-dependent DNA-binding could be mapped to the central/carboxy-terminal domain. In addition, using MALDI-TOF-MS with a non-acidic matrix, we show that two zinc ions are bound to the amino-terminal domain. Other zinc ion(s) bind the DNA-binding domain. Binding of zinc to ASR1 induces conformational changes resulting in a decreased sensitivity to proteases. 相似文献
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A Feldmann C Arndt K Töpfer S Stamova F Krone M Cartellieri S Koristka I Michalk D Lindemann M Schmitz A Temme M Bornhäuser G Ehninger M Bachmann 《Journal of immunology (Baltimore, Md. : 1950)》2012,189(6):3249-3259
Prostate cancer is the most common noncutaneous malignancy in men. The prostate stem cell Ag (PSCA) is a promising target for immunotherapy of advanced disease. Based on a novel mAb directed to PSCA, we established and compared a series of murine and humanized anti-CD3-anti-PSCA single-chain bispecific Abs. Their capability to redirect T cells for killing of tumor cells was analyzed. During these studies, we identified a novel bispecific humanized Ab that efficiently retargets T cells to tumor cells in a strictly Ag-dependent manner and at femtomolar concentrations. T cell activation, cytokine release, and lysis of target cells depend on a cross-linkage of redirected T cells with tumor cells, whereas binding of the anti-CD3 domain alone does not lead to an activation or cytokine release. Interestingly, both CD8(+) and CD4(+) T cells are activated in parallel and can efficiently mediate the lysis of tumor cells. However, the onset of killing via CD4(+) T cells is delayed. Furthermore, redirecting T cells via the novel humanized bispecific Abs results in a delay of tumor growth in xenografted nude mice. 相似文献
8.
Brown SD Palumbo AV Panikov N Ariyawansa T Klingeman DM Johnson CM Land ML Utturkar SM Epstein SS 《Journal of bacteriology》2012,194(12):3279-3280
Microbacterium laevaniformans strain OR221 was isolated from subsurface sediments obtained from the Field Research Center (FRC) in Oak Ridge, TN. It was characterized as a bacterium tolerant to heavy metals, such as uranium, nickel, cobalt, and cadmium, as well as nitrate and low pH. We present its draft genome sequence. 相似文献
9.
Elman NM Ben-Yoav H Sternheim M Rosen R Krylov S Shacham-Diamand Y 《Biosensors & bioelectronics》2008,23(11):1631-1636
A lab-on-chip consisting of a unique integration of whole-cell sensors, a MOEMS (Micro-Opto-Electro-Mechanical-System) modulator, and solid-state photo-detectors was implemented for the first time. Whole-cell sensors were genetically engineered to express a bioluminescent reporter (lux) as a function of the lac promoter. The MOEMS modulator was designed to overcome the inherent low frequency noise of solid-state photo-detectors by means of a previously reported modulation technique, named IHOS (Integrated Heterodyne Optical System). The bio-reporter signals were modulated prior to photo-detection, increasing the SNR of solid-state photo-detectors at least by three orders of magnitude. Experiments were performed using isopropyl-beta-d-thiogalactopyranoside (IPTG) as a preliminary step towards testing environmental toxicity. The inducer was used to trigger the expression response of the whole-cell sensors testing the sensitivity of the lab-on-chip. Low intensity bio-reporter optical signals were measured after the whole-cell sensors were exposed to IPTG concentrations of 0.1, 0.05, and 0.02 mM. The experimental results reveal the potential of this technology for future implementation as an inexpensive massive method for rapid environmental toxicity detection. 相似文献
10.
Wei-Yan Zhang Ye Yuan Deng-Quan Su Xiao-Ping He Shuai-Bo Han Slava S. Epstein Shan He Min Wu 《Antonie van Leeuwenhoek》2018,111(10):1855-1862
A Gram-stain negative, rod-shaped, non-motile, strictly aerobic bacterium HK-28T was isolated from a mangrove sediment sample in Haikou city, Hainan Province, China. Strain HK-28T was able to grow at 10–45 °C (optimum 25–30 °C), pH 5.0–8.5 (optimum 6.0–7.0) and 0.5–12.0% (w/v) NaCl (optimum 1.0–3.0%, w/v). The major cellular fatty acids were C16:0, Summed Feature 8 (C18:1 ω7c and/or C18:1 ω6c), Summed Feature 3 (C16:1 ω7c and/or C16:1 ω6c), C17:0, C12:0 3-OH and C17:1ω8c. Ubiquinone-8 (Q-8) was the predominant respiratory quinone. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, two unidentified aminophospholipids, four unidentified phospholipids, two unidentified glycolipid, an unidentified glycophospholipid, an unidentified aminolipid and an unidentified lipid. The DNA G+C content was 50.2 mol%. Accoroding to 16S rRNA gene sequence similarities, strain HK-28T shared 97.1 and 96.7% sequence similarities to the validly named species Gallaecimonas xiamenensis MCCC 1A01354T and Gallaecimonas pentaromativorans MCCC 1A06435T, respectively, and shared lower sequence similarities (<?92.0%) to all other genera. Phylogenetic analysis showed strain HK-28T was clustered with G. pentaromativorans MCCC 1A06435T and G. xiamenensis MCCC 1A01354T. Strain HK-28T showed low DNA–DNA relatedness with G. xiamenensis MCCC 1A01354T (28.3?±?1.5%) and G. pentaromativorans MCCC 1A06435T (25.2?±?2.4%). On the basis of phenotypic, chemotaxonomic and genotypic characteristics, strain HK-28T is considered to represent a novel species in the genus Gallaecimonas, for which the name Gallaecimonas mangrovi sp. nov. is proposed. The type strain is HK-28T (=?KCTC 62177T?=?MCCC 1K03441). 相似文献