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151.
Biodegradation of crude oil and pure hydrocarbons by extreme halophilic archaea from hypersaline coasts of the Arabian Gulf 总被引:3,自引:0,他引:3
D. M. Al-Mailem N. A. Sorkhoh H. Al-Awadhi M. Eliyas S. S. Radwan 《Extremophiles : life under extreme conditions》2010,14(3):321-328
Two extreme halophilic Haloferax strains and one strain each of Halobacterium and Halococcus were isolated from a hypersaline coastal area of the Arabian Gulf on a mineral salt medium with crude oil vapor as a sole
source of carbon and energy. These archaea needed at least 1 M NaCl for growth in culture, and grew best in the presence of
4 M NaCl or more. Optimum growth temperatures lied between 40 and 45oC. The four archaea were resistant to the antibiotics
chloramphenicol, cycloheximide, nalidixic acid, penicillin, streptomycin and tetracycline. The strains could grow on a wide
scope of aliphatic and aromatic (both mono-and polynuclear) hydrocarbons, as sole sources of carbon and energy. Quantitative
measurements revealed that these extreme halophilic prokaryotes could biodegrade crude oil (13–47%, depending on the strain
and medium salinity), n-octadecane (28–67%) and phenanthrene (13–30%) in culture after 3 weeks of incubation. The rates of biodegradation by all
strains were enhanced with increasing NaCl concentration in the medium. Optimal concentration was 3 M NaCl, but even with
4 M NaCl the hydrocarbon-biodegradation rates were higher than with 1 and 2 M NaCl. It was concluded that these archaea could
contribute to self-cleaning and bioremediation of oil-polluted hypersaline environments. 相似文献
152.
Beadell JS Ishtiaq F Covas R Melo M Warren BH Atkinson CT Bensch S Graves GR Jhala YV Peirce MA Rahmani AR Fonseca DM Fleischer RC 《Proceedings. Biological sciences / The Royal Society》2006,273(1604):2935-2944
The introduction of avian malaria (Plasmodium relictum) to Hawaii has provided a model system for studying the influence of exotic disease on naive host populations. Little is known, however, about the origin or the genetic variation of Hawaii's malaria and traditional classification methods have confounded attempts to place the parasite within a global ecological and evolutionary context. Using fragments of the parasite mitochondrial gene cytochrome b and the nuclear gene dihydrofolate reductase-thymidylate synthase obtained from a global survey of greater than 13000 avian samples, we show that Hawaii's avian malaria, which can cause high mortality and is a major limiting factor for many species of native passerines, represents just one of the numerous lineages composing the morphological parasite species. The single parasite lineage detected in Hawaii exhibits a broad host distribution worldwide and is dominant on several other remote oceanic islands, including Bermuda and Moorea, French Polynesia. The rarity of this lineage in the continental New World and the restriction of closely related lineages to the Old World suggest limitations to the transmission of reproductively isolated parasite groups within the morphological species. 相似文献
153.
Evidence that DNA (cytosine-5) methyltransferase regulates synaptic plasticity in the hippocampus 总被引:7,自引:0,他引:7
Levenson JM Roth TL Lubin FD Miller CA Huang IC Desai P Malone LM Sweatt JD 《The Journal of biological chemistry》2006,281(23):15763-15773
DNA (cytosine-5) methylation represents one of the most widely used mechanisms of enduring cellular memory. Stable patterns of DNA methylation are established during development, resulting in creation of persisting cellular phenotypes. There is growing evidence that the nervous system has co-opted a number of cellular mechanisms used during development to subserve the formation of long term memory. In this study, we examined the role DNA (cytosine-5) methyltransferase (DNMT) activity might play in regulating the induction of synaptic plasticity. We found that the DNA within promoters for reelin and brain-derived neurotrophic factor, genes implicated in the induction of synaptic plasticity in the adult hippocampus, exhibited rapid and dramatic changes in cytosine methylation when DNMT activity was inhibited. Moreover, zebularine and 5-aza-2-deoxycytidine, inhibitors of DNMT activity, blocked the induction of long term potentiation at Schaffer collateral synapses. Activation of protein kinase C in the hippocampus decreased reelin promoter methylation and increased DNMT3A gene expression. Interestingly, DNMT activity is required for protein kinase C-induced increases in histone H3 acetylation. Considered together, these results suggest that DNMT activity is dynamically regulated in the adult nervous system and that DNMT may play a role in regulating the induction of synaptic plasticity in the mature CNS. 相似文献
154.
Walter Jaoko Etienne Karita Kayitesi Kayitenkore Gloria Omosa-Manyonyi Susan Allen Soe Than Elizabeth M. Adams Barney S. Graham Richard A. Koup Robert T. Bailer Carol Smith Len Dally Bashir Farah Omu Anzala Claude M. Muvunyi Jean Bizimana Tony Tarragona-Fiol Philip J. Bergin Peter Hayes Martin Ho Kelley Loughran Wendy Komaroff Gwynneth Stevens Helen Thomson Mark J. Boaz Josephine H. Cox Claudia Schmidt Jill Gilmour Gary J. Nabel Patricia Fast Job Bwayo 《PloS one》2010,5(9)
Background
We conducted a double-blind, randomized, placebo-controlled Phase I study of a recombinant replication-defective adenovirus type 5 (rAd5) vector expressing HIV-1 Gag and Pol from subtype B and Env from subtypes A, B and C, given alone or as boost following a DNA plasmid vaccine expressing the same HIV-1 proteins plus Nef, in 114 healthy HIV-uninfected African adults.Methodology/Principal Findings
Volunteers were randomized to 4 groups receiving the rAd5 vaccine intramuscularly at dosage levels of 1×1010 or 1×1011 particle units (PU) either alone or as boost following 3 injections of the DNA vaccine given at 4 mg/dose intramuscularly by needle-free injection using Biojector® 2000. Safety and immunogenicity were evaluated for 12 months. Both vaccines were well-tolerated. Overall, 62% and 86% of vaccine recipients in the rAd5 alone and DNA prime - rAd5 boost groups, respectively, responded to the HIV-1 proteins by an interferon-gamma (IFN-γ) ELISPOT. The frequency of immune responses was independent of rAd5 dosage levels. The highest frequency of responses after rAd5 alone was detected at 6 weeks; after DNA prime - rAd5 boost, at 6 months (end of study). At baseline, neutralizing antibodies against Ad5 were present in 81% of volunteers; the distribution was similar across the 4 groups. Pre-existing immunity to Ad5 did not appear to have a significant impact on reactogenicity or immune response rates to HIV antigens by IFN-γ ELISPOT. Binding antibodies against Env were detected in up to 100% recipients of DNA prime - rAd5 boost. One volunteer acquired HIV infection after the study ended, two years after receipt of rAd5 alone.Conclusions/Significance
The HIV-1 rAd5 vaccine, either alone or as a boost following HIV-1 DNA vaccine, was well-tolerated and immunogenic in African adults. DNA priming increased the frequency and magnitude of cellular and humoral immune responses, but there was no effect of rAd5 dosage on immunogenicity endpoints.Trial Registration
ClinicalTrials.gov NCT00124007相似文献155.
Tremaine Gregory Farah Carrasco‐Rueda Jessica Deichmann Joseph Kolowski Alfonso Alonso 《Biotropica》2017,49(2):249-255
While natural resource exploration and extraction activity is expanding in the Neotropics, our understanding of wildlife response to such activity is almost non‐existent. Primates, which fulfill important ecological roles and face numerous anthropogenic threats, are of particular concern. We studied primate group distribution before, during, and after natural gas pipeline construction in the Peruvian Amazon to investigate whether primates spatially avoid areas of disturbance. We monitored primates on eight transects 20 times per annual sampling period in three consecutive years and analyzed changes in group observations relative to the pipeline right‐of‐way in a multi‐season occupancy modeling framework. Overall primate group encounter rates were low (<half) compared to a nearby protected area. Contrary to expectations, we did not see clear evidence of spatial avoidance of the pipeline area. Although higher overall encounter rates before construction suggested lower primate use of the area during and following construction, this pattern could not be confirmed statistically, and probability of colonization and extinction of transect sections in the occupancy analysis could not be differentiated from zero. These results are probably attributable to a combination of low numbers of primate encounters and high spatial variability in primate use of different transects. This study provides valuable preliminary data and a methodological framework for understanding the response of an ecologically important group of mammals to anthropogenic activity. We encourage other researchers to continue exploring the impacts of natural resource exploration‐ and extraction‐related activities in the tropics, as such activities are likely to have a growing effect on ecosystems. 相似文献
156.
Edgar E. Llontop William Cenens Denize C. Favaro Germn G. Sgro Roberto K. Salinas Cristiane R. Guzzo Chuck S. Farah 《PLoS pathogens》2021,17(8)
Type IV pili (T4P) are thin and flexible filaments found on the surface of a wide range of Gram-negative bacteria that undergo cycles of extension and retraction and participate in a variety of important functions related to lifestyle, defense and pathogenesis. During pilus extensions, the PilB ATPase energizes the polymerization of pilin monomers from the inner membrane. In Xanthomonas citri, two cytosolic proteins, PilZ and the c-di-GMP receptor FimX, are involved in the regulation of T4P biogenesis through interactions with PilB. In vivo fluorescence microscopy studies show that PilB, PilZ and FimX all colocalize to the leading poles of X. citri cells during twitching motility and that this colocalization is dependent on the presence of all three proteins. We demonstrate that full-length PilB, PilZ and FimX can interact to form a stable complex as can PilB N-terminal, PilZ and FimX C-terminal fragments. We present the crystal structures of two binary complexes: i) that of the PilB N-terminal domain, encompassing sub-domains ND0 and ND1, bound to PilZ and ii) PilZ bound to the FimX EAL domain within a larger fragment containing both GGDEF and EAL domains. Evaluation of PilZ interactions with PilB and the FimX EAL domain in these and previously published structures, in conjunction with mutagenesis studies and functional assays, allow us to propose an internally consistent model for the PilB-PilZ-FimX complex and its interactions with the PilM-PilN complex in the context of the inner membrane platform of the X. citri Type IV pilus. 相似文献
157.
We have shown previously that clitoral stimulation (CLS) of female rats induces significant conditioned place preference (CPP), indicating that it is rewarding. The present study asked whether CLS could induce a conditioned partner preference. In the first experiment, sexually naïve females received 10 alternating trials of CLS and No-CLS in the presence of a male rat behind a wire-mesh screen. For one group, CLS was made in the presence of the male scented with almond extract. On alternating trials, those females received sham CLS in the presence of an unscented male behind the screen. The order was reversed for the other group. After 5 trials in each condition, females were placed into an open field with two sexually vigorous males, one scented and the other unscented. Contrary to expectation, females displayed a preference for the male associated with sham CLS. The second experiment examined whether a partner preference could be conditioned by associating CLS with the almond odor alone. A new group of sexually naive females received the same CLS-odor, No-CLS-No Odor pairings as above, but with the odor presented on cotton gauze in the chamber. During the final open field test, those females selectively solicited the scented male. We conclude that CLS that induces CPP also induces conditioned partner preference. However, we propose that CLS in the presence of an inaccessible male created a sexual inhibitory state for female rats. 相似文献
158.
Lavoie C Roy L Lanoix J Taheri M Young R Thibault G Farah CA Leclerc N Paiement J 《Progress in histochemistry and cytochemistry》2011,46(1):1-48
The endoplasmic reticulum (ER) is a highly dynamic organelle. It is composed of four subcompartments including nuclear envelope (NE), rough ER (rER), smooth ER (sER) and transitional ER (tER). The subcompartments are interconnected, can fragment and dissociate and are able to reassemble again. They coordinate with cell function by way of protein regulators in the surrounding cytosol. The activity of the many associated molecular machines of the ER as well as the fluid nature of the limiting membrane of the ER contribute extensively to the dynamics of the ER. This review examines the properties of the ER that permit its isolation and purification and the physiological conditions that permit reconstitution both in vitro and in vivo in normal and in disease conditions. 相似文献
159.
160.