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131.
Two different stator systems drive a single polar flagellum in Shewanella oneidensis MR-1 总被引:1,自引:1,他引:0
Anja Paulick rea Koerdt Jürgen Lassak Stuart Huntley Ina Wilms Franz Narberhaus Kai M. Thormann 《Molecular microbiology》2009,71(4):836-850
The Gram-negative metal ion-reducing bacterium Shewanella oneidensis MR-1 is motile by means of a single polar flagellum. We identified two potential stator systems, PomAB and MotAB, each individually sufficient as a force generator to drive flagellar rotation. Physiological studies indicate that PomAB is sodium-dependent while MotAB is powered by the proton motive force. Flagellar function mainly depends on the PomAB stator; however, the presence of both stator systems under low-sodium conditions results in a faster swimming phenotype. Based on stator homology analysis we speculate that MotAB has been acquired by lateral gene transfer as a consequence of adaptation to a low-sodium environment. Expression analysis at the single cell level showed that both stator systems are expressed simultaneously. An active PomB–mCherry fusion protein effectively localized to the flagellated cell pole in 70–80% of the population independent of sodium concentrations. In contrast, polar localization of MotB–mCherry increased with decreasing sodium concentrations. In the absence of the Pom stator, MotB–mCherry localized to the flagellated cell pole independently of the sodium concentration but was rapidly displaced upon expression of PomAB. We propose that selection of the stator occurs at the level of protein localization in response to sodium concentrations. 相似文献
132.
Microfluidic PCR-based target enrichment: A case study in two rapid radiations of Commiphora (Burseraceae) from Madagascar 下载免费PDF全文
Developing effective and cost-efficient multilocus nuclear datasets for angiosperm species is a continuing challenge to the systematics community. Here we describe the development and validation of a novel set of 91 nuclear markers for PCR-based target enrichment. Using microfluidic PCR and Illumina MiSeq, we generated nuclear, subgenomic libraries for 96 species simultaneously and sequenced them for a total cost of ca. $6000 USD. Approximately half of these costs include reusable reagents (primers, barcodes, and custom sequencing primers) and taxon sampling could be increased by an order of magnitude to maximize sequencing depth efficiency. The principle benefit of microfluidic PCR over alternative target enrichment strategies is that it bypasses costly library preparation. After sequencing, we evaluated the ability of the loci to resolve species level relationships within two recently radiated lineages of endemic Madagascan Commiphora Jacq. (Burseraceae) species. Our results demonstrate that (i) effective nuclear markers can be designed for non-model angiosperm taxa from these publicly available datasets; (ii) that microfluidic PCR amplification followed by high throughput sequencing can produce highly complete taxon by locus sequence data matrices with minimal resource investment; and (iii) that these numerous nuclear phylogenomic markers can improve our understanding of phylogenetic relationships withinCommiphora. We provide a synopsis of ongoing activities to enhance this microfluidic PCR-based target enrichment strategy through broader primer assays, multiplexing, and increased efficiency of sequencing depth. 相似文献
133.
Mariano Rodrigues Wagner Manica Carlesso Daniel Kuhn Taciélen Altmayer Maira Cristina Martini Camila Durlo Tamiosso 《Biocatalysis and Biotransformation》2017,35(2):110-119
Some studies have carried out in order to retrieve proteins from the by-product of animal-processing industries. Earthworms are rich in protein and usually are used in animal feed. Thus, this study aimed to optimize the hydrolysis process of Eisenia andrei earthworms by employing Alcalase enzyme. Using the response surface methodology, we evaluated the following conditions: temperature, hydrolysis time, stirring speed, and enzyme/substrate ratio. The optimal conditions for the experimental design were determined through the analysis of the foaming and emulsifying properties, in vitro starch digestibility, and antioxidant activity. The results demonstrate that the highest degree of hydrolysis (i.e., 92%) was obtained under the following conditions: pH, 9.5; temperature, 25?°C; hydrolysis time, 2.25?h; stirring speed, 200?rpm; and enzyme/substrate ratio, 1.77%, using Alcalase enzyme. Evaluation of the amino acid composition under these conditions revealed higher concentrations of aspartic acid, glutamic acid, and leucine. The in vitro protein digestibility of the hydrolysate was approximately 73%. There were no significant improvements in either foam stability or emulsification after enzymatic hydrolysis. Additional studies on the antioxidant activity are required. This bioproduct could potentially serve as a promising supplementary food product. 相似文献
134.
135.
Manica A 《Biological reviews of the Cambridge Philosophical Society》2002,77(2):261-277
This review summarizes information on filial cannibalism (the act of eating one's own offspring) in teleost fish. Cannibalistic parents can either consume their whole brood (total filial cannibalism), or eat only some of the eggs in the nest (partial filial cannibalism). Offspring consumption has been argued to be adaptive under the assumption that offspring survival is traded against feeding, and that offspring can act as an alternative food source for the parents. The evidence supporting the basic predictions formulated under these assumptions is summarized for both total and partial filial cannibalism. These two forms of cannibalism differ significantly since the former represents an investment only in future reproductive success, whereas the latter can affect both present and future reproductive success. Despite a few inconsistencies in the data from laboratory and field studies, the energy-based explanation appears valid for both forms of cannibalism. Alternative non-energy-based explanations are considered, but they are unable to account for the wide distribution of this behaviour in teleosts. The intersexual conflict arising from attempts of the non-cannibal sex to minimize the cost of filial cannibalism is also discussed, together with the potential effect of this behaviour on the operational sex ratio at a population level. 相似文献
136.
137.
Muhammad Ilyas Jong-Soo Kim Jesse Cooper Young-Ah Shin Hak-Min Kim Yun Sung Cho Seungwoo Hwang Hyunho Kim Jaewoo Moon Oksung Chung JeHoon Jun Achal Rastogi Sanghoon Song Junsu Ko Andrea Manica Ziaur Rahman Tayyab Husnain Jong Bhak 《BMC genomics》2015,16(1)
Background
Pakistan covers a key geographic area in human history, being both part of the Indus River region that acted as one of the cradles of civilization and as a link between Western Eurasia and Eastern Asia. This region is inhabited by a number of distinct ethnic groups, the largest being the Punjabi, Pathan (Pakhtuns), Sindhi, and Baloch.Results
We analyzed the first ethnic male Pathan genome by sequencing it to 29.7-fold coverage using the Illumina HiSeq2000 platform. A total of 3.8 million single nucleotide variations (SNVs) and 0.5 million small indels were identified by comparing with the human reference genome. Among the SNVs, 129,441 were novel, and 10,315 nonsynonymous SNVs were found in 5,344 genes. SNVs were annotated for health consequences and high risk diseases, as well as possible influences on drug efficacy. We confirmed that the Pathan genome presented here is representative of this ethnic group by comparing it to a panel of Central Asians from the HGDP-CEPH panels typed for ~650 k SNPs. The mtDNA (H2) and Y haplogroup (L1) of this individual were also typical of his geographic region of origin. Finally, we reconstruct the demographic history by PSMC, which highlights a recent increase in effective population size compatible with admixture between European and Asian lineages expected in this geographic region.Conclusions
We present a whole-genome sequence and analyses of an ethnic Pathan from the north-west province of Pakistan. It is a useful resource to understand genetic variation and human migration across the whole Asian continent.Electronic supplementary material
The online version of this article (doi:10.1186/s12864-015-1290-1) contains supplementary material, which is available to authorized users. 相似文献138.
Enrico Brugnoli rea Scartazza Mario Carmelo De Tullio Maria Cristina Monteverdi Marco Lauteri Angela Augusti 《Physiologia plantarum》1998,104(4):727-734
The relationships between non‐radiative energy dissipation and the carotenoid content, especially the xanthophyll cycle components, were studied in sun and shade leaves of several plants possessing C3 ( Hedera helix and Laurus nobilis ) or C4 ( Zea mays and Sorghum bicolor ) photosynthetic pathways. Sun‐shade acclimation caused marked changes in the organisation and function of photosynthetic apparatus, including significant variation in carotenoid content and composition. The contents of zanthophyll cycle pigments were higher in sun than in shade leaves in all species, but this difference was considerably greater in C3 than in C4 plants. The proportion of photoconvertible violaxanthin, that is the amount of violaxanthin (V) which can actually be de‐epoxidised to zeaxanthin, was much greater in sun than in shade leaves. The amount of photoconvertible V was always linearly dependent on the chlorophyll a/b ratio, although the slope of the relationship varied especially between C3 and C4 species. The leaf zeaxanthin and antheraxanthin contents were correlated with non‐radiative energy dissipation in all species under different light environments. These relationships were curvilinear and variable between sun and shade leaves and between C3 and C4 species. Hence, the dissipation of excess energy does not appear to be univocally dependent on zeaxanthin content and other photoprotective mechanisms may be involved under high irradiance stress. Such mechanisms appear largely variable between C3 and C4 species according to their photosynthetic characteristics. 相似文献
139.
140.
Abstract: A continuous dual 13 CO2 and 15 NH4 15 NO3 labelling experiment was undertaken to determine the effects of ambient (350μmol mol-1 ) or elevated (700μmol mol-1 ) atmospheric CO2 concentrations on C and N uptake and allocation within 3-year-old beech ( Fagus sylvatica L.) during leafing. After six weeks of growth, total carbon uptake was increased by 63 % (calculated on total C content) under elevated CO2 but the carbon partitioning was not altered. 56 % of the new carbon was found in the leaves. On a dry weight basis was the content of structural biomass in leaves 10 % lower and the lignin content remained unaffected under elevated as compared to ambient [CO2 ]. Under ambient [CO2 ] 37 %, and under elevated [CO2 ] 51 %, of the lignin C of the leaves derived from new assimilates. For both treatments, internal N pools provided more than 90 % of the nitrogen used for leaf-growth and the partitioning of nitrogen was not altered under elevated [CO2 ]. The C/N ratio was unaffected by elevated [CO2 ] at the whole plant level, but the C/N ratio of the new C and N uptake was increased by 32 % under elevated [CO2 ]. 相似文献