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1.
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Reverse simulation models of facial expression recognition suggest that we recognize the emotions of others by running implicit motor programmes responsible for the production of that expression. Previous work has tested this theory by examining facial expression recognition in participants with Möbius sequence, a condition characterized by congenital bilateral facial paralysis. However, a mixed pattern of findings has emerged, and it has not yet been tested whether these individuals can imagine facial expressions, a process also hypothesized to be underpinned by proprioceptive feedback from the face. We investigated this issue by examining expression recognition and imagery in six participants with Möbius sequence, and also carried out tests assessing facial identity and object recognition, as well as basic visual processing. While five of the six participants presented with expression recognition impairments, only one was impaired at the imagery of facial expressions. Further, five participants presented with other difficulties in the recognition of facial identity or objects, or in lower-level visual processing. We discuss the implications of our findings for the reverse simulation model, and suggest that facial identity recognition impairments may be more severe in the condition than has previously been noted.  相似文献   

3.
Enterotoxigenic Escherichia coli (ETEC) is one of the major causes of infectious diarrhea in developing countries. In order to characterize the molecular features of human ETEC isolates from Korea, we investigated the profiles of enterotoxin and colonization factor (CF) genes by polymerase chain reaction (PCR) and performed multilocus sequence typing (MLST) with a total of 291 ETEC strains. The specimens comprised 258 domestic strains isolated from patients who had diarrhea and were from widely separated geographic regions in Korea and 33 inflow strains isolated from travelers visiting other Asian countries. Heat-stable toxin (STh)-possessing ETEC strains were more frequent than heat-labile toxin (LT)-possessing ETEC strains in the domestic isolates, while the detection rates of both enterotoxin genes were similar in the inflow isolates. The profile of CF genes of domestic isolates was similar to that of inflow isolates and the major CF types of the strains were CS3-CS21-CS1/PCF071 and CS2-CS3-CS21. Most of these 2 CF types were detected in ETEC strains that possess both lt and sth genes. The major MLSTST types of domestic isolates were ST171 and ST955. Moreover, the 2 major CF types were usually found concomitantly with the 2 major MLST STs, ST171 and ST955. In conclusion, our genotyping results may provide useful information for guiding the development of geographically specific vaccines against human ETEC isolates.  相似文献   

4.
Feedback loops involving soil microorganisms can regulate plant populations. Here, we hypothesize that microorganisms are most likely to play a role in plant–soil feedback loops when they possess an affinity for a particular plant and the capacity to consistently affect the growth of that plant for good or ill. We characterized microbial communities using whole-community DNA fingerprinting from multiple "home-and-away" experiments involving giant ragweed (Ambrosia trifida L.) and common sunflower (Helianthus annuus L.), and we looked for affinity–effect relationships in these microbial communities. Using canonical ordination and partial least squares regression, we developed indices expressing each microorganism's affinity for ragweed or sunflower and its putative effect on plant biomass, and we used linear regression to analyze the relationship between microbial affinity and effect. Significant linear affinity–effect relationships were found in 75 % of cases. Affinity–effect relationships were stronger for ragweed than for sunflower, and ragweed affinity–effect relationships showed consistent potential for negative feedback loops. The ragweed feedback relationships indicated the potential involvement of multiple microbial taxa, resulting in strong, consistent affinity–effect relationships in spite of large-scale microbial variability between trials. In contrast, sunflower plant–soil feedback may involve just a few key players, making it more sensitive to underlying microbial variation. We propose that affinity–effect relationship can be used to determine key microbial players in plant–soil feedback against a low "signal-to-noise" background of complex microbial datasets.  相似文献   

5.
Single-stage nitritation–anammox combines the growth of aerobic ammonium-oxidizing bacteria (AOB) and anaerobic ammonium oxidizing bacteria (AnAOB) in one reactor. The necessary compromise of their milieu conditions often leads to the growth of nitrite-oxidizing bacteria (NOB). For this study, a sequencing batch reactor (SBR) for nitritation–anammox was operated for 180 days with sewage sludge reject water (removal capacity, 0.4 kg?N?m?3?day?1). The growth of NOB was favored by enhanced oxygen supply rather than extended aerobic phases. Suspended-type biomass from this SBR was taken regularly and sieved into three size fractions (all of them <1,000 μm). Batch experiments as well as fluorescence in situ hybridization were performed to study the distribution and activity of AnAOB, AOB, and NOB within those size fractions. Both the measured conversion rates and detected abundances decreased with increasing size fraction. The highest anammox conversion rates (15 g NH4 +–N per kilogram VSS per hour) and the highest abundances of Brocadia fulgida were found in the medium size fraction (100–315 μm). The batch experiments proved to be accurate tools for the monitoring of multiple processes in the reactor. The results were representative for reactor performance during the 6 months of reactor operation.  相似文献   

6.
Population density and biomass of bacteria and meiofauna were investigated seasonally in the sediments of the north-western bank of Red Sea. Samples of sediments were collected seasonally from three different stations to determine microphytobenthic biomass (chlorophyll a), protein, lipid, carbohydrate, and total organic matter concentrations. These investigations revealed that microbial components tended to increase their dominancy, whereas sensitive meiofauna were extremely reduced during the entire study period. Thus a very low density of the total meiofauna (with an annual average of 109 ± 26 ind./10 cm2) was recorded whilst the benthic microbial population densities exhibited higher values (ranging from 0.31 ± 0.02 × 108 to 43.67 ± 18.62 × 108/g dry sediment). These changes in the relative importance analysis of benthic microbial components versus meiofaunal ones seem to be based on the impact of organic matter accumulation on the function and structure of these benthic communities. Proteins, lipids and carbohydrates showed very low concentration values, and the organic matter mostly consisted of carbohydrates, reflecting lower nutritional values for benthic fauna in general and meiofauna in particular. The distribution of microbial and meiofaunal communities seems to be dependent on the quality of the organic matter rather than on its quantity. Total organic matter concentrations varied between 5.8 and 7.6 mg/g, with organic carbon accounting for only 32% of the total organic matter. Chlorophyll a attained very low values, fluctuating between 0.11 and 0.56 μg/g, indicating the oligotrophy of the studied area. The very low concentration of chlorophyll a in the Red Sea sediment suggests that the sedimentary organic matter, heterotrophic bacteria and/or protozoa constitute an alternative resource that is consumed by meiofauna when algae are less abundant. Protozoa, therefore, represent the “missing link in bacteria–meiofauna interaction in the Red Sea marine sediment ecosystem.  相似文献   

7.
Noroviruses are recognized as one of the leading causes of viral acute gastroenteritis, responsible for almost 50% of acute gastroenteritis outbreaks worldwide. The positive single-strand RNA genome of noroviruses presents a high mutation rate and these viruses are constantly evolving by nucleotide mutation and genome recombination. Norovirus recombinant strains have been detected as causing acute gastroenteritis outbreaks in several countries. However, in Brazil, only one report of a norovirus recombinant strain (GII.P7/GII.20) has been described in the northern region so far. For this study, 38 norovirus strains representative of outbreaks, 11 GII.4 and 27 non-GII.4, were randomly selected and amplified at the ORF1/ORF2 junction. Genetic recombination was identified by constructing phylogenetic trees of the polymerase and capsid genes, and further SimPlot and Bootscan analysis of the ORF1/ORF2 overlap. Sequence analysis revealed that 23 out of 27 (85%) non-GII.4 noroviruses were recombinant strains, characterized as: GII.P7/GII.6 (n = 9); GIIP.g/GII.12 (n = 4); GII.P16/GII.3 (n = 4); GII.Pe/GII.17 (n = 2); GII.P7/GII.14 (n = 1); GII.P13/GII.17 (n = 1); GII.P21/GII.3 (n = 1); and GII.P21/GII.13 (n = 1). On the other hand, among the GII.4 variants analyzed (Den Haag_2006b and New Orleans_2009) no recombination was observed. These data revealed the great diversity of norovirus recombinant strains associated with outbreaks, and describe for the first time these recombinant types circulating in Brazil. Our results obtained in southern Brazil corroborate the previous report for the northern region, demonstrating that norovirus recombinant strains are circulating more frequently than we expected. In addition, these results emphasize the relevance of including ORF1/ORF2-based analysis in surveillance studies as well as the importance of characterizing strains from other Brazilian regions to obtain epidemiological data for norovirus recombinant strains circulating in the country.  相似文献   

8.
The lolines are a class of bioprotective alkaloids that are produced by Epichloë species, fungal endophytes of grasses. These alkaloids are saturated 1-aminopyrrolizidines with a C2 to C7 ether bridge, and are structurally differentiated by the various modifications of the 1-amino group: -NH2 (norloline), -NHCH3 (loline), -N(CH3)2 (N-methylloline), -N(CH3)Ac (N-acetylloline), -NHAc (N-acetylnorloline), and -N(CH3)CHO (N-formylloline). Other than the LolP cytochrome P450, which is required for conversion of N-methylloline to N-formylloline, the enzymatic steps for loline diversification have not yet been established. Through isotopic labeling, we determined that N-acetylnorloline is the first fully cyclized loline alkaloid, implying that deacetylation, methylation, and acetylation steps are all involved in loline alkaloid diversification. Two genes of the loline alkaloid biosynthesis (LOL) gene cluster, lolN and lolM, were predicted to encode an N-acetamidase (deacetylase) and a methyltransferase, respectively. A knockout strain lacking both lolN and lolM stopped the biosynthesis at N-acetylnorloline, and complementation with the two wild-type genes restored production of N-formylloline and N-acetylloline. These results indicated that lolN and lolM are required in the steps from N-acetylnorloline to other lolines. The function of LolM as an N-methyltransferase was confirmed by its heterologous expression in yeast resulting in conversion of norloline to loline, and of loline to N-methylloline. One of the more abundant lolines, N-acetylloline, was observed in some but not all plants with symbiotic Epichloë siegelii, and when provided with exogenous loline, asymbiotic meadow fescue (Lolium pratense) plants produced N-acetylloline, suggesting that a plant acetyltransferase catalyzes N-acetylloline formation. We conclude that although most loline alkaloid biosynthesis reactions are catalyzed by fungal enzymes, both fungal and plant enzymes are responsible for the chemical diversification steps in symbio.  相似文献   

9.
Trends in Medical Mycology (TIMM) has become the essential leading meeting in the field of fungal infections, attracting clinicians and scientists from all over the world to attend state-of-the-art lectures, workshops and meet-the-expert sessions. TIMM-6, held in Copenhagen, Denmark, from 11 to 14 October 2013, was no exception, featuring presentations highlighting the potentially serious global threat presented by emerging fungal diseases and the continuing challenge of diagnosing and managing affected patients.  相似文献   

10.
Abstract The enrichment of several genes (xylE, nahAcd, todC1C2BA, tmoABCDE, alkB) that encode enzymes responsible for key steps in the degradation of hydrocarbons, and one gene specific to rRNA group I of the genus Pseudomonas, was studied in DNA extracted from a fuel oil–contaminated field site, and in laboratory microcosms (with the exception of alkB). Toluene, ethylbenzene, xylene, and naphthalene concentrations were related to the extent of hybridization of the genes in the field studies. Significant differences were observed in the extent of hybridization of some of the genes between contaminated and noncontaminated samples. In the microcosm studies, gasoline at rates ranging from 0.5 mg to 125 mg gasoline/g of soil as applied to soils, and the changes in hybridization intensity of these genes monitored with time. The lower threshold of gene enrichment of these genes in response to gasoline addition was below 0.5 mg/g soil. Small increases were observed at the 0.5-mg exposure level, but hybridization intensity quickly decreased to levels below detection 6–8 days after addition of the gasoline. A dose-response effect was observed from treatments with gasoline concentrations ranging from 0.5 to 35 mg/g soil. Inhibition by toxic components in gasoline was observed at 75 and 125 mg/g soil levels. Hybridization of the Pseudomonas group 1 probe to field DNA was not significantly enriched in the contaminated field site, although these sequences were enriched in the microcosm studies. Among the genes tested, xylE was the most sensitive indicator of low levels of fuel oil contamination. Received: 23 July 1996; Accepted 9 October 1996  相似文献   

11.

Background

Campylobacter jejuni is a common cause of acute gastroenteritis and is associated with post-infectious neuropathies such as the Guillain-Barré syndrome (GBS) and the Miller Fisher syndrome (MFS). We here present comparative genotyping of 49 C. jejuni strains from Bangladesh that were recovered from patients with enteritis or GBS. All strains were serotyped and analyzed by lipo-oligosaccharide (LOS) genotyping, amplified fragment length polymorphism (AFLP) analysis, multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE).

Methodology/Principal Findings

C. jejuni HS:23 was a predominant serotype among GBS patients (50%), and no specific serotype was significantly associated with GBS compared to enteritis. PCR screening showed that 38/49 (78%) of strains could be assigned to LOS classes A, B, C, or E. The class A locus (4/7 vs 3/39; p<0.01) was significantly associated in the GBS-related strains as compared to enteritis strains. All GBS/oculomotor related strains contained the class B locus; which was also detected in 46% of control strains. Overlapping clonal groups were defined by MLST, AFLP and PFGE for strains from patients with gastroenteritis and GBS. MLST defined 22 sequence types (STs) and 7 clonal complexes including 7 STs not previously identified (ST-3742, ST-3741, ST-3743, ST-3748, ST-3968, ST-3969 and ST-3970). C. jejuni HS:23 strains from patients with GBS or enteritis were clonal and all strains belonged to ST-403 complex. Concordance between LOS class B and ST-403 complex was revealed. AFLP defined 25 different types at 90% similarity. The predominant AFLP type AF-20 coincided with the C. jejuni HS:23 and ST-403 complex.

Conclusion/Significance

LOS genotyping, MLST, AFLP and PFGE helped to identify the HS:23 strains from GBS or enteritis patients as clonal. Overall, genotypes exclusive for enteritis or for GBS-related strains were not obtained although LOS class A was significantly associated with GBS strains. Particularly, the presence of a clonal and putative neuropathogenic C. jejuni HS:23 serotype may contribute to the high prevalence of C. jejuni related GBS in Bangladesh.  相似文献   

12.
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Abstract

As a famous plateau lake and a place rich in biodiversity located at the Hengduan Mountains, there is little research on microbial diversity and community composition in Erhai. In this study, 770,425 16S rRNA sequences had obtained at different depth samples. The abundance‐based coverage estimates (ACE), Chao1, and Shannon indices indicated the high abundance and diversity of Erhai sediment microorganisms. And they were obviously affected by human disturbance. Gammaproteobacteria, Deltaproteobacteria, Bacteroidia, Anaerolineae, Phycisphaerae, and Methanomicrobia were dominant bacteria and existed in almost all samples. The content of total nitrogen (TN) in sediments had a significant positive correlation between Syntrophus, Deltaproteobacteria, Desulfatiglans, Oxyphotobacteria, Clostridiales, Burkholderiaceae, Geobacter, Crenothrix species richness. Desulfobacca, Syntrophus, Deltaproteobacteria, Desulfatiglans, Gammaproteobacteria, Oxyphotobacteria, and Clostridiales were positively correlated with the nitrates in sediments. And the species richness of Desulfatiglans was correlated with NO2 -. The RDA analysis was shown that dbRDA1 was affected mainly by the depth of lake, while the content of TN, NO3 ?, NO2 ?, and NH4 + had the largest effect on dbRDA2. The results indicated the great relations between the diversity and composition of microbial communities and different forms of sediment nitrogen in Erhai lake sediments.  相似文献   

14.
Prokaryotes were analyzed in the samples of ice and soils collected by the joint Russian-German-Mongolian expedition (2006) at the site of archeological excavations of two Pazyryk culture mounds in the upper Olon-Kurin-Gol River on the southern slope of the Saylyugem Mountains, Mongolian Altai. Phylogenetic analysis of the 16S rRNA gene fragments of the cultured bacteria revealed three major groups wide-spread in permafrost soils: Firmicutes, Actinobacteria, and Gammaproteobacteria. Analysis of the total DNA from the samples revealed nonculturable bacteria of the phyla Alphaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Actinobacteria, Chloroflexi, Gemmatoidetes, Firmicutes, and CFB (Cytophaga-Flavobacteria-Bacteroidetes) isolated from the samples of permafrost soils (Arctic, tundra, and from Tibet highlands), groundwater, and Arctic and Antarctic ice cores.  相似文献   

15.
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17.

Background

With the upcoming licensure of Outer Membrane Protein-based vaccines against meningococcal disease, data on disease incidence and molecular characteristic of circulating N. meningitidis strains in Latin American countries is needed. Chile is, to date, one of the few countries in the region that has performed this type of work in a comprehensive collection of disease-associated strains from two consecutive years, 2010–2011.

Methods

A total of 119 N. meningitidis strains isolated from patients with invasive disease in Chile in 2010–2011 were characterized by the National Reference Laboratory. Serogroup determination, MLST and porA typing were performed.

Results

Serogroup B was predominant in both study years, but W135 experienced a noticeable increase in 2011 compared to 2010. ST-11 complex, ST-41/44 complex ST-32 complex were the most prevalent among the isolates, and were strongly associated with serogroups W135 (ST-11 Complex) and B (ST-41/44 and ST-32 complexes). Likewise, the major porA types detected were strongly associated with these three clonal complexes: P1.5,2 was found exclusively among W135:ST-11 isolates, whereas P1.7, 2–3 was only detected in C:ST-11. ST-41/44 isolates mainly had P1.10-8, and ST-32 complex were associated with a P1.18-8 porA.

Conclusions

Our data show disease-associated N. meningitidis circulating in Chile are similar to those found in other parts of the world. The increase on W135:ST-11 isolates observed in 2011 foretold the unusual epidemiological situation experienced in the country in 2012, and MLST data show that this strain is indistinguishable from the one linked to the global Hajj 2000-related outbreak that occurred in 2001. Finally, this work demonstrates the importance of maintaining a strong national surveillance program integrating clinical, epidemiological and laboratory data and incorporating gold standard diagnostic and characterization techniques that allow the data to be compared all over the world.  相似文献   

18.
Xiao S  Xie X  Liu J  He Z  Hu Y 《Current microbiology》2008,57(3):239-244
Four samples were studied from four separated sites with heap leaching in the Yinshan Lead-Zinc Mine and the Dongxiang Copper Mine in Jiangxi province, China. The compositions and structures of archaeal communities in four sites were identified by a polymerase chain reaction-based cloning approach. A total of six operational taxonomic units (OTUs) was obtained from four samples. The highest percentage of overlapped OTUs was 88.9% between sites DX and D1. Phylogenetic analysis revealed that archaea in the four acid mineral bioleaching systems fell into two divisions: Thermoplasma and Ferroplasma. The proportions of Thermoplasma and Ferroplasma in all four sites were 20.6% and 79.4%, respectively. The proportions of clones clustered with Ferroplasma in four sites were 93.8% (D1), 30.5% (D3), 100% (DY), and 93.2% (DX), respectively. The proportions of clones clustered with Thermoplasma in the other three sites were 6.2% (D1), 69.5% (D3), and 6.8% (DX), respectively. The results of principal component analysis based on the percentages of six OTUs obtained from four sites and geochemical data from four sites suggested that the concentrations of elements such as lead, cobalt, and sulfur might be the reason causing the different archaeal structure in site D3 than those in the other three sites.  相似文献   

19.
Probiotics and Antimicrobial Proteins - Obesity is one of the major causes of the development of metabolic diseases, particularly cardiovascular diseases and type-2 diabetes mellitus. Increased...  相似文献   

20.
Targeted genetic manipulation using homologous recombination is the method of choice for functional genomic analysis to obtain a detailed view of gene function and phenotype(s). The development of mutant strains with targeted gene deletions, targeted mutations, complemented gene function, and/or tagged genes provides powerful strategies to address gene function, particularly if these genetic manipulations can be efficiently targeted to the gene locus of interest using integration mediated by double cross over homologous recombination.Due to very high rates of nonhomologous recombination, functional genomic analysis of Toxoplasma gondii has been previously limited by the absence of efficient methods for targeting gene deletions and gene replacements to specific genetic loci. Recently, we abolished the major pathway of nonhomologous recombination in type I and type II strains of T. gondii by deleting the gene encoding the KU80 protein1,2. The Δku80 strains behave normally during tachyzoite (acute) and bradyzoite (chronic) stages in vitro and in vivo and exhibit essentially a 100% frequency of homologous recombination. The Δku80 strains make functional genomic studies feasible on the single gene as well as on the genome scale1-4.Here, we report methods for using type I and type II Δku80Δhxgprt strains to advance gene targeting approaches in T. gondii. We outline efficient methods for generating gene deletions, gene replacements, and tagged genes by targeted insertion or deletion of the hypoxanthine-xanthine-guanine phosphoribosyltransferase (HXGPRT) selectable marker. The described gene targeting protocol can be used in a variety of ways in Δku80 strains to advance functional analysis of the parasite genome and to develop single strains that carry multiple targeted genetic manipulations. The application of this genetic method and subsequent phenotypic assays will reveal fundamental and unique aspects of the biology of T. gondii and related significant human pathogens that cause malaria (Plasmodium sp.) and cryptosporidiosis (Cryptosporidium).  相似文献   

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