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31.
Ruofan Wang Camille R. Simoneau Jessie Kulsuptrakul Mehdi Bouhaddou Katherine A. Travisano Jennifer M. Hayashi Jared Carlson-Stevermer James R. Zengel Christopher M. Richards Parinaz Fozouni Jennifer Oki Lauren Rodriguez Bastian Joehnk Keith Walcott Kevin Holden Anita Sil Jan E. Carette Nevan J. Krogan Andreas S. Puschnik 《Cell》2021,184(1):106-119.e14
32.
Biological soil crusts in ecological restoration: emerging research and perspectives 总被引:1,自引:0,他引:1
Anita Antoninka Akasha Faist Emilio Rodriguez‐Caballero Kristina E. Young V. Bala Chaudhary Lea A. Condon David A. Pyke 《Restoration Ecology》2020,28(Z2):S3-S8
Drylands encompass over 40% of terrestrial ecosystems and face significant anthropogenic degradation causing a loss of ecosystem integrity, services, and deterioration of social‐ecological systems. To combat this degradation, some dryland restoration efforts have focused on the use of biological soil crusts (biocrusts): complex communities of cyanobacteria, algae, lichens, bryophytes, and other organisms living in association with the top millimeters of soil. Biocrusts are common in many ecosystems and especially drylands. They perform a suite of ecosystem functions: stabilizing soil surfaces to prevent erosion, contributing carbon through photosynthesis, fixing nitrogen, and mediating the hydrological cycle in drylands. Biocrusts have emerged as a potential tool in restoration; developing methods to implement effective biocrust restoration has the potential to return many ecosystem functions and services. Although culture‐based approaches have allowed researchers to learn about the biology, physiology, and cultivation of biocrusts, transferring this knowledge to field implementation has been more challenging. A large amount of research has amassed to improve our understanding of biocrust restoration, leaving us at an opportune time to learn from one another and to join approaches for maximum efficacy. The articles in this special issue improve the state of our current knowledge in biocrust restoration, highlighting efforts to effectively restore biocrusts through a variety of different ecosystems, across scales and utilizing a variety of lab and field methods. This collective work provides a useful resource for the scientific community as well as land managers. 相似文献
33.
An exopolysaccharide producing marine bacterium, Enterobacter cloacae, was isolated from marine sediment collected from Gujarat coast, India. Chemical investigation of exopolysaccharide (EPS 71 a) revealed that this exopolysaccharide was an acidic polysaccliaride containing high amount of uronic acid, fucose and sulfate which is rare for bacterial exopolysaccharides. EPS 71a was found to have fucose, galactose, glucose and glucuronic acid in a molar ratio of 2: 1: 1: 1. 相似文献
34.
Lentiviral reporter constructs for fluorescence tracking of the temporospatial pattern of Smad3 signaling 总被引:1,自引:0,他引:1
Canonical TGF-beta is involved in cell differentiation, tissue maintenance, and wound healing, but also plays a central role in the pathogenesis of diseases such as cancer Here we describe a lentivirus-based reporter vector system expressing green fluorescent protein (GFP) or red fluorescent protein (RFP) under the control of a Smad3-responsive element (CAGA)12 that allows observation of the temporospatial pattern of endogeneous Smad3-mediated signaling on a cellular level. Use of this method will be valuable to identify cells with active Smad3 signaling and investigate the role of endogenous Smad3 signaling in complex systems such as co-cultures in vitro, or in tumors during tumor cell invasion and metastasis in vivo. 相似文献
35.
金缕梅科银缕梅属与帕罗堤属的亲缘关系——核糖体DNA ITS序列证据 总被引:6,自引:0,他引:6
本文对金缕梅科弗特吉族(Molinadendron和Matudaea除外)的细胞核核糖体DNA ITS片段进行了序列分析,在此基础上对该族的演化关系、尤其是中国特有属银缕梅属的系统位置进行了最简约分支分析。基本结果如下:其一,蚊母族和狭义的弗特吉族均不形成自己的单系分支,因此,支持Endress的处理,即合并两族为广义的弗特吉族;其二,银缕梅属同帕罗堤属有着密切的亲缘关系,支持形态学和解剖学结论;其三,根据该片段核苷酸序列的演化速率推算出的银缕梅属和帕罗堤属间分化时间为晚中新世。此结论大致与化石记录相符。 相似文献
36.
Gentili F Nilsson MC Zackrisson O DeLuca TH Sellstedt A 《Journal of experimental botany》2005,56(422):3121-3127
Cyanobacteria colonizing the feather moss Pleurozium schreberi were isolated from moss samples collected in northern Sweden and subjected to physiological and molecular characterization. Morphological studies of isolated and moss-associated cyanobacteria were carried out by light microscopy. Molecular tools were used for cyanobacteria identification, and a reconstitution experiment of the association between non-associative mosses and cyanobacteria was conducted. The influence of temperature on N2 fixation in the different cyanobacterial isolates and the influence of light and temperature on N2-fixation rates in the moss were studied using the acetylene reduction assay. Two different cyanobacteria were effectively isolated from P. schreberi: Nostoc sp. and Calothrix sp. A third genus, Stigonema sp. was identified by microscopy, but could not be isolated. The Nostoc sp. was found to fix N2 at lower temperatures than Calothrix sp. Nostoc sp. and Stigonema sp. were the predominant cyanobacteria colonizing the moss. The attempt to reconstitute the association between the moss and cyanobacteria was successful. The two isolated genera of cyanobacteria in feather moss samples collected in northern Sweden differ in their temperature optima, which may have important ecological implications. 相似文献
37.
Allison Lange Milo B. Fasken Murray Stewart Anita H. Corbett 《Traffic (Copenhagen, Denmark)》2020,21(10):622-635
The importin α/β transport machinery mediates the nuclear import of cargo proteins that bear a classical nuclear localization sequence (cNLS). These cargo proteins are linked to the major nuclear protein import factor, importin‐β, by the importin‐α adapter, after which cargo/carrier complexes enter the nucleus through nuclear pores. In the nucleus, cargo is released by the action of RanGTP and the nuclear pore protein Nup2, after which the importins are recycled to the cytoplasm for further transport cycles. The nuclear export of importin‐α is mediated by Cse1/CAS. Here, we exploit structures of functionally important complexes to identify residues that are critical for these interactions and provide insight into how cycles of protein import and recycling of importin‐α occur in vivo using a Saccharomyces cerevisiae model. We examine how these molecular interactions impact protein localization, cargo import, function and complex formation. We show that reversing the charge of key residues in importin‐α (Arg44) or Cse1 (Asp220) results in loss of function of the respective proteins and impairs complex formation both in vitro and in vivo. To extend these results, we show that basic residues in the Nup2 N‐terminus are required for both Nup2 interaction with importin‐α and Nup2 function. These results provide a more comprehensive mechanistic model of how Cse1, RanGTP and Nup2 function in concert to mediate cNLS‐cargo release in the nucleus. 相似文献
38.
Lauri Nikkanen Anita Santana Snchez Maria Ermakova Matthias Rgner Laurent Cournac Yagut Allahverdiyeva 《The Plant journal : for cell and molecular biology》2020,103(4):1460-1476
In oxygenic photosynthetic organisms, excluding angiosperms, flavodiiron proteins (FDPs) catalyze light‐dependent reduction of O2 to H2O. This alleviates electron pressure on the photosynthetic apparatus and protects it from photodamage. In Synechocystis sp. PCC 6803, four FDP isoforms function as hetero‐oligomers of Flv1 and Flv3 and/or Flv2 and Flv4. An alternative electron transport pathway mediated by the NAD(P)H dehydrogenase‐like complex (NDH‐1) also contributes to redox hemostasis and the photoprotection of photosynthesis. Four NDH‐1 types have been characterized in cyanobacteria: NDH‐11 and NDH‐12, which function in respiration; and NDH‐13 and NDH‐14, which function in CO2 uptake. All four types are involved in cyclic electron transport. Along with single FDP mutants (?flv1 and Δflv3) and the double NDH‐1 mutants (?d1d2, which is deficient in NDH‐11,2 and ?d3d4, which is deficient in NDH‐13,4), we studied triple mutants lacking one of Flv1 or Flv3, and NDH‐11,2 or NDH‐13,4. We show that the presence of either Flv1/3 or NDH‐11,2, but not NDH‐13,4, is indispensable for survival during changes in growth conditions from high CO2/moderate light to low CO2/high light. Our results show functional redundancy between FDPs and NDH‐11,2 under the studied conditions. We suggest that ferredoxin probably functions as a primary electron donor to both Flv1/3 and NDH‐11,2, allowing their functions to be dynamically coordinated for efficient oxidation of photosystem I and for photoprotection under variable CO2 and light availability. 相似文献
39.
Lucy E. Ridding Adrian C. Newton Sally A. Keith Robin M. Walls Anita Diaz Richard F. Pywell James M. Bullock 《Ecography》2021,44(1):33-43
The extinction debt, delayed species extinctions following landscape degradation, is a widely discussed concept. But a consensus about the prevalence of extinctions debts is hindered by a multiplicity of methods and a lack of comparisons among habitats. We applied three contrasting species–area relationship methods to test for plant community extinction debts in three habitats which had different degradation histories over the last century: calcareous grassland, heathland and woodland. These methods differ in their data requirements, with the first two using information on past and current habitat area alongside current species richness, whilst the last method also requires data on past species richness. The most data‐intensive, and hence arguably most reliable method, identified extinction debts across all habitats for specialist species, whilst the other methods did not. All methods detected an extinction debt in calcareous grassland, which had undergone the most severe degradation. We conclude that some methods failed to detect an extinction debt, particularly in habitats that have undergone moderate degradation. Data on past species numbers are required for the most reliable method; as such data are rare, extinction debts may be under‐reported. 相似文献
40.
Amino Acids - Solid-phase synthesis of cyclic, branched or side-chain-modified peptides typically involves introduction of a residue carrying a temporary side-chain protecting group that undergoes... 相似文献