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1.
This paper concerns the taxonomic status of the F38-like group (MacOwan), a prime determinant of contagious caprine pleuropneumonia (CCPP). Extensive biochemical and serological investigations on strain F38 are reported. Some complex serological relationships with other mycoplasma species are revealed. The results, taken in conjunction with earlier published work on geno-typic characters, lead to the conclusion that final classification of these organisms should await further comparative studies of a number of field strains with a related group of strains classified as M. capri-colum. The characterization of F38 confirms its partial relationship to the “M. mycoides group” of ovine/caprine/bovine mycoplasmas, and has also revealed a very close phenotypic relationship to the bovine mycoplasma serogroup 7, a finding of potential diagnostic and epidemiological importance.  相似文献   

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The record of theropod dinosaurs in Brazil is very scarce. One of the most promising lithostratigraphic units for those reptiles is the Bauru Group. The dinosaur remains found in this unit are mainly those of sauropods, while theropods are represented mostly by teeth. Here we describe a right scapula (housed at the Earth Science Museum of the Departamento Nacional de Produção Mineral/Rio de Janeiro) that is the first theropod scapula reported from the Cretaceous of Brazil and only the second osteological evidence of the Tetanurae from the Bauru Group. The specimen was recovered from the outskirts of Peirópolis, in Minas Gerais State. Comparisons with other theropod dinosaurs are limited, but the overall morphology of the new specimen indicates that it is neither a member of the Abelisauridae nor a member of the Avialae. It also differs from more basal members of the Theropoda, but its overall shape is consistent with several derived members of the Tetanurae, likely a non-avialan maniraptoran. Despite the lack of precision in its taxonomic position, the new specimen confirms the presence of non-avialan Maniraptora in the Bauru Group.  相似文献   

4.
Byrne RW  Bates LA 《Current biology : CB》2007,17(20):R883-R884
In testing the 'social brain hypothesis' with comparative data, most research has used group size as an index of cognitive challenge. Recent work suggests that this measure is too crude to apply to a wide range of species, and biologists may need to develop other ways of extending these analyses.  相似文献   

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Abstract

A new 2′-hydroxyl protecting group, [[2-(methylthio)phenyl]thio]methyl (MPTM), was introduced into the 2′-position of adenosine, guanosine and cytidine building units required for the synthesis of oligoribonucleotides.  相似文献   

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Ⅱ组内含子(groupⅡintron)存在于原生生物、真菌、藻类、植物细胞器以及细菌和古细菌基因组中.在体内,Ⅱ组内含子可通过两步连续的转酯反应从前体RNA中自剪接,并连接两侧外显子.许多Ⅱ组内含子的剪接反应是由蛋白质辅助完成的,这种蛋白质有的是由内含子编码,有的是由宿主基因编码.Ⅱ组内含子能够有效地归巢进入无内含子的等位基因,也能够以低频率逆转座进入非等位基因.转座过程依赖内含子RNA和内含子编码的蛋白质(内切核酸酶活性和逆转录酶活性).本论文在总结Ⅱ组内含子最新研究成果的基础上,分析Ⅱ组内含子可能的起源和进化途径.  相似文献   

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In platelets, group IVA cytosolic phospholipase A2 (cPLA2α) has been implicated as a key regulator in the hydrolysis of platelet membrane phospholipids, leading to pro-thrombotic thromboxane A2 and anti-thrombotic 12-(S)-hydroxyeicosatetranoic acid production. However, studies using cPLA2α-deficient mice have indicated that other PLA2(s) may also be involved in the hydrolysis of platelet glycerophospholipids. In this study, we found that group VIB Ca2+-independent PLA2 (iPLA2γ)-deficient platelets showed decreases in adenosine diphosphate (ADP)-dependent aggregation and ADP- or collagen-dependent thromboxane A2 production. Electrospray ionization mass spectrometry analysis of platelet phospholipids revealed that fatty acyl compositions of ethanolamine plasmalogen and phosphatidylglycerol were altered in platelets from iPLA2γ-null mice. Furthermore, mice lacking iPLA2γ displayed prolonged bleeding times and were protected against pulmonary thromboembolism. These results suggest that iPLA2γ is an additional, long-sought-after PLA2 that hydrolyzes platelet membranes and facilitates platelet aggregation in response to ADP.  相似文献   

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《Ethnic and racial studies》2012,35(8):1392-1408
Abstract

Despite increasing demand from policymakers and academics alike, effective policies on ethnic data collection for social inclusion purposes are still absent in most of Europe. This paper proposes to explain the failure to produce these policies by the coexistence of and tensions among contradictory frames on ethnic counting. An in-depth analysis of Hungarian policies reveals that three mutually inconsistent policy frames connect ethnic counting to ethnic diversity in many different ways. These frames are group self-determination, individual rights, and social inclusion. This paper illustrates the tensions among the three through a discussion of two core but divisive aspects of collecting ethnic statistics: defining ethnic classifications for counting and defining membership in ethnic groups for policy purposes. Tensions among the three result in inconsistent and inefficient policies of ethnic counting.  相似文献   

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The Upper Cenomanian–Lower Turonian litho-stratigraphic units of the Danubian Cretaceous Group of the proximal Bodenwöhrer Senke (Regensburg, Eibrunn and Winzerberg formations, the latter consisting of a lower Reinhausen Member and an upper Knollensand Member), have been investigated with a focus on facies analysis and sequence stratigraphy. Analyses of litho-, bio-, and microfacies resulted in the recognition of 12 predominantly marine facies types for the Eibrunn and Winzerberg formations. Petrographic and paleontological properties as well as gradual transitions in the sections suggest that their depositional environment was a texturally graded, predominantly siliciclastic, storm-dominated shelf. The muddy–siliceous facies types FT 1–3 have been deposited below the storm wave-base in an outer shelf setting. Mid-shelf deposits are represented by fine- to medium-grained, bioturbated, partly glauconitic sandstones (FT 4–6). Coarse-grained, gravelly and/or shell-bearing sandstones (FT 7–10) developed in the inner shelf zone. Highly immature, arkosic coarse-grained sandstones and conglomerates (FT 11 and 12) characterize an incised, high-gradient braided river system. The Winzerberg Formation with its general coarsening- and thickening-upward trend reflects a regressive cycle culminating in a subaerial unconformity associated with a coarse-grained, gravelly unit of marine to fluvial origin known as the “Hornsand” which is demonstrably diachronous. The overlying Altenkreith Member of the Roding Formation signifies the onset of a new transgressive cycle in the early Middle Turonian. The sequence stratigraphic analysis suggests that the deposition of the Upper Cenomanian and Lower Turonian strata of the Bodenwöhrer Senke took place in a single cycle of third-order eustatic sea-level change between the major sequence boundaries SB Ce 5 (mid-Late Cenomanian) and SB Tu 1 (Early–Middle Turonian boundary interval). The southeastern part of the Bodenwöhrer Senke was flooded in the mid-Late Cenomanian (Praeactinocamax plenus transgression) and a second transgressive event occurred in the earliest Turonian. In the central and northwestern parts of the Bodenwöhrer Senke, however, the initial transgression occurred during the earliest Turonian, related to pre-transgression topography. Thus, the Regensburg and Eibrunn formations are increasingly condensed here and cannot be separated anymore. Following an earliest Turonian maximum flooding, the Lower Turonian Winzerberg Formation filled the available accommodation space, explaining its constant thickness of 35–40 m across the Bodenwöhrer Senke and excluding tectonic activity during this interval. Rapid sea-level fall at SB Tu 1 terminated this depositional sequence. This study shows that Late Cenomanian–Early Turonian deposition in the Bodenwöhrer Senke was governed by eustatic sea-level changes.  相似文献   

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Ⅱ组内含子(group Ⅱ intron)存在于原生生物、真菌、藻类、植物细胞器以及细菌和古细菌基因组中.在体内,Ⅱ组内含子可通过两步连续的转酯反应从前体RNA中自剪接,并连接两 侧外显子.许多Ⅱ组内含子的剪接反应是由蛋白质辅助完成的,这种蛋白质有的是由内含子编码,有的是由宿主基因编码.Ⅱ组内含子能够有效地归巢进入无内含子的等位基因,也能 够以低频率逆转座进入非等位基因.转座过程依赖内含子RNA和内含子编码的蛋白质(内切核酸酶活性和逆转录酶活性).本论文在总结Ⅱ组内含子最新研究成果的基础上,分析Ⅱ组内含子可能的起源和进化途径  相似文献   

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《Animal behaviour》1988,36(6):1708-1728
Reproductive conflict within groups can be an important feature of cooperative breeding systems, especially when more than one individual of a sex breeds within a social group. Relationships between group structure, dominance, within-group conflict and reproductive tactics of cooperatively breeding Galápagos mockingbirds were examined on Isla Genovesa. Territorial groups of 2–24 adults included up to three breeding females, with 42% of the groups containing more than one (plural groups); females in most plural groups nested separately. Territory size increased with group size, but the area available per pair in plural groups was smaller than in singular groups (groups with only one breeding pair). Most pairings were monogamous, and males usually outnumbered females; high-ranking males obtained mates more frequently than subordinate males. In 3 relatively dry years, but not in a wet El Niño year, subordinate pairs in plural groups fledged fewer young than dominant pairs or pairs breeding in singular groups. Interference by dominant breeders, often leading to abandonment of nests by subordinate pairs, appears to account for these differences: through nest disruption in drier years, dominant individuals may reduce the cost of sharing their territories and increase the chances of recruiting helpers. Dominant males in plural groups may also father young through extra-pair copulations with subordinate females. Despite costs imposed by within-group conflict, subordinate breeders have higher long-term reproductive success than birds that defer breeding. Plural group structure is maintained because unpredictable climatic variation favours opportunistic breeding by subordinates.  相似文献   

17.

Background

Brazil is the world''s largest producer of sugarcane. Harvest is predominantly manual, exposing workers to health risks: intense physical exertion, heat, pollutants from sugarcane burning.

Design

Panel study to evaluate the effects of burnt sugarcane harvesting on blood markers and on cardiovascular system.

Methods

Twenty-eight healthy male workers, living in the countryside of Brazil were submitted to blood markers, blood pressure, heart rate variability, cardiopulmonary exercise testing, sympathetic nerve activity evaluation and forearm blood flow measures (venous occlusion plethysmography) during burnt sugarcane harvesting and four months later while they performed other activities in sugar cane culture.

Results

Mean participant age was 31±6.3 years, and had worked for 9.8±8.4 years on sugarcane work. Work during the harvest period was associated with higher serum levels of Creatine Kinase – 136.5 U/L (IQR: 108.5–216.0) vs. 104.5 U/L (IQR: 77.5–170.5), (p = 0.001); plasma Malondialdehyde–7.5±1.4 µM/dl vs. 6.9±1.0 µM/dl, (p = 0.058); Glutathione Peroxidase – 55.1±11.8 Ug/Hb vs. 39.5±9.5 Ug/Hb, (p<0.001); Glutathione Transferase– 3.4±1.3 Ug/Hb vs. 3.0±1.3 Ug/Hb, (p = 0.001); and 24-hour systolic blood pressure – 120.1±10.3 mmHg vs. 117.0±10.0 mmHg, (p = 0.034). In cardiopulmonary exercise testing, rest-to-peak diastolic blood pressure increased by 11.12 mmHg and 5.13 mmHg in the harvest and non-harvest period, respectively. A 10 miliseconds reduction in rMSSD and a 10 burst/min increase in sympathetic nerve activity were associated to 2.2 and 1.8 mmHg rises in systolic arterial pressure, respectively.

Conclusion

Work in burnt sugarcane harvesting was associated with changes in blood markers and higher blood pressure, which may be related to autonomic imbalance.  相似文献   

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We analyzed near-complete population (composite) genomic sequences for coexisting acidophilic iron-oxidizing Leptospirillum group II and III bacteria (phylum Nitrospirae) and an extrachromosomal plasmid from a Richmond Mine, Iron Mountain, CA, acid mine drainage biofilm. Community proteomic analysis of the genomically characterized sample and two other biofilms identified 64.6% and 44.9% of the predicted proteins of Leptospirillum groups II and III, respectively, and 20% of the predicted plasmid proteins. The bacteria share 92% 16S rRNA gene sequence identity and >60% of their genes, including integrated plasmid-like regions. The extrachromosomal plasmid carries conjugation genes with detectable sequence similarity to genes in the integrated conjugative plasmid, but only those on the extrachromosomal element were identified by proteomics. Both bacterial groups have genes for community-essential functions, including carbon fixation and biosynthesis of vitamins, fatty acids, and biopolymers (including cellulose); proteomic analyses reveal these activities. Both Leptospirillum types have multiple pathways for osmotic protection. Although both are motile, signal transduction and methyl-accepting chemotaxis proteins are more abundant in Leptospirillum group III, consistent with its distribution in gradients within biofilms. Interestingly, Leptospirillum group II uses a methyl-dependent and Leptospirillum group III a methyl-independent response pathway. Although only Leptospirillum group III can fix nitrogen, these proteins were not identified by proteomics. The abundances of core proteins are similar in all communities, but the abundance levels of unique and shared proteins of unknown function vary. Some proteins unique to one organism were highly expressed and may be key to the functional and ecological differentiation of Leptospirillum groups II and III.To understand how microorganisms contribute to biogeochemical cycling, it is necessary to determine the roles of uncultivated as well as cultivated groups and to establish how these roles vary during ecological succession and when environmental conditions change. Shotgun genomic sequencing (metagenomics) has opened new opportunities for culture-independent studies of microbial communities. Examples include investigations of acid mine drainage (AMD) biofilm communities (4, 43, 75), symbiosis in a marine worm involving sulfur-oxidizing and sulfate-reducing bacteria (85), and enhanced biological phosphorous removal by sludge communities (32). From these genomic data sets, it has been possible to reconstruct aspects of the metabolism of individual organisms (32) and coexisting community members (29, 75) and to identify which organisms contribute community-essential functions (75). An interesting question relates to how differences in metabolic potential between organisms from the same lineage allow them to occupy distinct niches. Identification of potentially adaptive traits in closely related organisms is also important from an evolutionary perspective.Genomic data do not reveal how organisms alter their metabolisms in response to the presence of other organisms or environmental conditions. Proteomics methods for analysis of metabolic responses of isolates (16, 17, 42, 80, 81) have been extended to analyze the functioning of the dominant members of natural consortia (56, 69), with strain-level resolution (43, 82). In these studies, peptides are separated by liquid chromatography (LC) and identified by tandem mass spectrometry (MS-MS) through reference to appropriate genomic databases. Proteomic analysis is possible even if the genome sequences are not identical to those of the organisms present (24); however, missing sequence information reduces the resolution of such proteogenomic studies.Due to dominance by a few organism types, chemoautotrophic microbial AMD biofilms from Richmond Mine, Iron Mountain, CA, are tractable model systems used to develop cultivation-independent metagenomic and proteogenomic methods for analysis of community structure, function, and ecology (13). Acidophilic Leptospirillum bacteria dominate this AMD system (15), other AMD systems (54), and bioleaching systems used for recovery of metals (19, 53, 86). These bacteria play pivotal roles in sulfide mineral dissolution because they are iron oxidizers (53, 75), and ferric iron drives sulfide oxidation, leading to formation of metal-rich sulfuric acid solutions. According to a recent microscopy-based study (83), Leptospirillum group II are the first colonists in AMD biofilm communities whereas Leptospirillum group III generally appear later, sometimes partitioned within biofilm interiors. Because only Leptospirillum group III appear to be able to fix nitrogen, they may be keystone species in AMD ecosystems (75). This observation enabled the isolation of one representative, “Leptospirillum ferrodiazotrophum” (76). In prior work, we reported near-complete genome sequences of two Leptospirillum group II types (43, 65), but detailed functional annotations and metabolic analyses have not been published. Genomic data have been used to explore the metabolism of Leptospirillum bacteria in one biofilm community (56), but proteomic and genomic analyses of the same biofilm community have not been performed.Here, we report a near-complete genomic sequence for Leptospirillum group III, derived from a biofilm obtained from the UBA site within the Richmond Mine, Iron Mountain, CA; a detailed functional annotation of the genomes of Leptospirillum groups II and III; and a genomic and proteomic comparison of them. In addition, we report the sequence of an extrachromosomal plasmid associated with these organisms. This study represents the first comprehensive genomics-based analysis of the metabolism of bacteria in the Nitrospirae phylum and the first environmental community proteogenomic study where the genomic and proteomic data were derived from the same sample. We compared the proteomic profiles of three different biofilm communities to evaluate the importance of shared and unique genes and pathways in environmental adaptation.  相似文献   

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This paper presents an investigation into marginalizing racism, a form of prejudice whereby ingroup members claim that specific individuals belong to their group, but also exclude them by not granting them all of the privileges of a full ingroup member. One manifestation of this is that perceived degree of outgroup membership will covary negatively with degree of ingroup membership. That is, group membership may be treated as a zero-sum quantity (e.g., one cannot be both Australian and Iraqi). Study 1 demonstrated that judges allocate more zero-sum membership assignments and lower combined membership in their country of origin and their adopted country to high-threat migrants than low-threat migrants. Study 2 identified a subtle type of zero-sum reasoning which holds that stronger degree of membership in one’s original nationality constrains membership in a new nationality to a greater extent than stronger membership in the new nationality constrains membership in one’s original nationality. This pattern is quite general, being replicated in large samples from four nations (USA, UK, India, and China). Taken together, these studies suggest that marginalizing racism is more than a belief that people retain a “stain” from membership in their original group. Marginalizing racism also manifests itself as conditional zero-sum beliefs about multiple group memberships.  相似文献   

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