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161.
The hatching process in embryos of the toad Xenopus laevis consists of two temporally distinct phases. In phase 1, the embryo escapes sequentially from the two outermost jelly layers, J3 and J2, and during phase 2 the embryo hatches from the last remaining jelly coat layer J1 and the fertilization envelope. Phase 1 hatching appears to be a physical process caused by water inbibition of jelly coat layer J1 and dynamic changes in the volume enclosed by the fertilization envelope. The combined turgor pressure ruptures jelly coat layers J3 and J2. The subsequent phase 2 hatching is a result of both physical and chemical processes. Phase 1 hatching exposes layer J1 to the medium which, in contrast to jelly layers J2 and J3 is partially soluble, and permits its gradual dissolution during Phase 2. The embryo secretes a proteolytic enzyme from the frontal region which partially digests the fertilization envelope; subsequent embryo movement ruptures the weakened envelope and completes the hatching process. 相似文献
162.
Fan Nana Wen Wuwu Gao Li Lv Aimin Su Liantai Zhou Peng An Yuan 《Plant and Soil》2022,477(1-2):357-371
Plant and Soil - Aluminum (Al) stress is a global problem that inhibits root growth and crop production in acidic soils. The inhibitive effect is greatly attributed to the reduction of cell wall... 相似文献
163.
Xia Yan Liqing Wu Dandan He Yanan Zhang Hongmei Guo Xiaoning Gao Nana Wang Lili Huang 《Journal of Phytopathology》2019,167(11-12):624-632
Strain Hhs.015, a PGPR strain well‐studied for biocontrol of apple Valsa canker, was isolated from cucumber roots and classified as a new species of Saccharothrix yanglingensis. Hhs.015 was able to colonize apple tissue culture seedlings and trigger disease resistance. According to the whole‐genome sequence of S. yanglingensis Hhs.015, its secreted proteins were predicted and analysed, which can help to find out Hhs.015 functional substances that are involved in inducing plant system resistance and also the molecular mechanisms of the interaction between Hhs.015 and the host plants. Using the software SignalP4.1, TMHMM2.0, DAS‐TMfilter, HMMTOP, ScanProsite, PSORT and big‐PI predictor, 7,379 ORFs of the genome of S. yanglingensis Hhs.015 were predicted and analysed. Moreover, the function of ORFs where the signal peptides come from was predicted by Swissprot database. The selected proteins were obtained by prokaryotic expression. Their effects in inducing plant resistance to the pathogen Valsa mali, resistance‐related enzyme activity and growth promotion analysis were evaluated. In total, 158 ORFs with known function, such as serine proteinase and transpeptidase, were identified; the remaining 142 ORFs were function‐unknown putative proteins. Five putative proteins were successfully obtained by prokaryotic expression, and the results showed that the protein named 5620g could enhance the plant disease resistance to the pathogen V. mali, inhibit the expansion of lesions and upregulate the defence‐related enzyme activity. The protein named 3176g could prolongate cucumber root. In conclusion, biocontrol strain Hhs.015 may secrete protein elicitors to improve plant resistance to the pathogenic microorganism and promote the growth of host plants. 相似文献
164.
Nana Nehrbass Eckart Winkler Jana Müllerová Jan Pergl Petr Pyšek Irena Perglová 《Biological invasions》2007,9(4):383-395
Mechanisms and consequences of biological invasions are a global issue. Yet, one of the key aspects, the initial phase of
invasion, is rarely observed in detail. Data from aerial photographs covering the spread of Heracleum mantegazzianum (Apiaceae, native to Caucasus) on a local scale of hectares in the Czech Republic from the beginning of invasion were used
as an input for an individual-based model (IBM), based on small-scale and short-time data. To capture the population development
inferred from the photographs, long-distance seed dispersal, changes in landscape structures and suitability of landscape
elements to invasion by H. mantegazzianum were implemented in the model. The model was used to address (1) the role of long-distance dispersal in regional invasion
dynamics, and (2) the effect of land-use changes on the progress of the invasion. Simulations showed that already small fractions
of seed subjected to long-distance dispersal, as determined by systematic comparison of field data and modelling results,
had an over-proportional effect on the spread of this species. The effect of land-use changes on the simulated course of invasion
depends on the actual level of habitat saturation; it is larger for populations covering a high proportion of available habitat
area than for those in the initial phase of invasion. Our results indicate how empirical field data and model outputs can
be linked more closely with each other to improve the understanding of invasion dynamics. The multi-level, but nevertheless
simple structure of our model suggests that it can be used for studying the spread of similar species invading in comparable
landscapes. 相似文献
165.
166.
Isolation and proteomic analysis of the SYP61 compartment reveal its role in exocytic trafficking in Arabidopsis 总被引:1,自引:0,他引:1
Drakakaki G van de Ven W Pan S Miao Y Wang J Keinath NF Weatherly B Jiang L Schumacher K Hicks G Raikhel N 《Cell research》2012,22(2):413-424
The endomembrane system is a complex and dynamic intracellular trafficking network. It is very challenging to track individual vesicles and their cargos in real time; however, affinity purification allows vesicles to be isolated in their natural state so that their constituent proteins can be identified. Pioneering this approach in plants, we isolated the SYP61 trans-Golgi network compartment and carried out a comprehensive proteomic analysis of its contents with only minimal interference from other organelles. The proteome of SYP61 revealed the association of proteins of unknown function that have previously not been ascribed to this compartment. We identified a complete SYP61 SNARE complex, including regulatory proteins and validated the proteome data by showing that several of these proteins associated with SYP61 in planta. We further identified the SYP121-complex and cellulose synthases, suggesting that SYP61 plays a role in the exocytic trafficking and the transport of cell wall components to the plasma membrane. The presence of proteins of unknown function in the SYP61 proteome including ECHIDNA offers the opportunity to identify novel trafficking components and cargos. The affinity purification of plant vesicles in their natural state provides a basis for further analysis and dissection of complex endomembrane networks. The approach is widely applicable and can afford the study of several vesicle populations in plants, which can be compared with the SYP61 vesicle proteome. 相似文献
167.
Séverin Nguemezi Tchameni Dieudonné Nwaga Louise Nana Wakam Eddy Leonard Mangaptche Ngonkeu Raymond Fokom Jean Kuaté Francois‐Xavier Etoa 《Journal of Phytopathology》2012,160(5):220-228
The effects of some selected arbuscular mycorrhizal (AM) fungi, Gigaspora margarita and Glomus mossae on the growth and the role of soluble amino acids of two contrasting cocoa cultivars (ICS84 tolerant and SNK10 sensitive) against black pod disease caused by Phytophthora megakarya were investigated. Root colonization by AM fungi is between 50 and 70% 18 weeks after planting. Tested AM fungi significantly increased all the plant growth parameters (height, number of leaves, shoot and root matter) and P uptake as compared to non‐inoculated plants in pot experiments. AM fungi inoculated cocoa reduced the disease severity. Compared to the control, the soluble amino acid levels increased with inoculation of the AM fungi strains in the necrotic stems of disease on inoculated cocoa plants. Significant relationships between amino acids and disease severity observed for two cocoa cultivars imply that the induction of specific amino acids synthesized by leaves, such as arginine, cysteine and glutamic acid, may represent potential candidate molecules for adaptation of such cultivars to P. megakarya disease. Inoculating seedlings with AMF in nurseries could enhance the development of cocoa plants protected against P. megakarya. 相似文献
168.
Sayama T Ono E Takagi K Takada Y Horikawa M Nakamoto Y Hirose A Sasama H Ohashi M Hasegawa H Terakawa T Kikuchi A Kato S Tatsuzaki N Tsukamoto C Ishimoto M 《The Plant cell》2012,24(5):2123-2138
Triterpene saponins are a diverse group of biologically functional products in plants. Saponins usually are glycosylated, which gives rise to a wide diversity of structures and functions. In the group A saponins of soybean (Glycine max), differences in the terminal sugar species located on the C-22 sugar chain of an aglycone core, soyasapogenol A, were observed to be under genetic control. Further genetic analyses and mapping revealed that the structural diversity of glycosylation was determined by multiple alleles of a single locus, Sg-1, and led to identification of a UDP-sugar-dependent glycosyltransferase gene (Glyma07g38460). Although their sequences are highly similar and both glycosylate the nonacetylated saponin A0-αg, the Sg-1(a) allele encodes the xylosyltransferase UGT73F4, whereas Sg-1(b) encodes the glucosyltransferase UGT73F2. Homology models and site-directed mutagenesis analyses showed that Ser-138 in Sg-1(a) and Gly-138 in Sg-1(b) proteins are crucial residues for their respective sugar donor specificities. Transgenic complementation tests followed by recombinant enzyme assays in vitro demonstrated that sg-1(0) is a loss-of-function allele of Sg-1. Considering that the terminal sugar species in the group A saponins are responsible for the strong bitterness and astringent aftertastes of soybean seeds, our findings herein provide useful tools to improve commercial properties of soybean products. 相似文献
169.
Zhao Y Nakagawa T Itoh S Inamori K Isaji T Kariya Y Kondo A Miyoshi E Miyazaki K Kawasaki N Taniguchi N Gu J 《The Journal of biological chemistry》2006,281(43):32122-32130
N-acetylglucosaminyltransferase V (GnT-V) catalyzes the addition of beta1,6-GlcNAc branching of N-glycans, which contributes to metastasis. N-acetylglucosaminyltransferase III (GnT-III) catalyzes the formation of a bisecting GlcNAc structure in N-glycans, resulting in the suppression of metastasis. It has long been hypothesized that the suppression of GnT-V product formation by the action of GnT-III would also exist in vivo, which will consequently lead to the inhibition of biological functions of GnT-V. To test this, we draw a comparison among MKN45 cells, which were transfected with GnT-III, GnT-V, or both, respectively. We found that alpha3beta1 integrin-mediated cell migration on laminin 5 was greatly enhanced in the case of GnT-V transfectant. This enhanced cell migration was significantly blocked after the introduction of GnT-III. Consistently, an increase in bisected GlcNAc but a decrease in beta1,6-GlcNAc-branched N-glycans on integrin alpha3 subunit was observed in the double transfectants of GnT-III and GnT-V. Conversely, GnT-III knockdown resulted in increased migration on laminin 5, concomitant with an increase in beta1,6-GlcNAc-branched N-glycans on the alpha3 subunit in CHP134 cells, a human neuroblastoma cell line. Therefore, in this study, the priority of GnT-III for the modification of the alpha3 subunit may be an explanation for why GnT-III inhibits GnT-V-induced cell migration. Taken together, our results demonstrate for the first time that GnT-III and GnT-V can competitively modify the same target glycoprotein and furthermore positively or negatively regulate its biological functions. 相似文献
170.
Zhao Y Itoh S Wang X Isaji T Miyoshi E Kariya Y Miyazaki K Kawasaki N Taniguchi N Gu J 《The Journal of biological chemistry》2006,281(50):38343-38350
The core fucosylation (alpha1,6-fucosylation) of glycoprotein is widely distributed in mammalian tissues. Recently alpha1,6-fucosylation has been further reported to be very crucial by the study of alpha1,6-fucosyltransferase (Fut8)-knock-out mice, which shows the phenotype of emphysema-like changes in the lung and severe growth retardation. In this study, we extensively investigated the effect of core fucosylation on alpha3beta1 integrin and found for the first time that Fut8 makes an important contribution to the functions of this integrin. The role of core fucosylation in alpha3beta1 integrin-mediated events has been studied by using Fut8(+/+) and Fut8(-/-) embryonic fibroblasts, respectively. We found that the core fucosylation of alpha3beta1 integrin, the major receptor for laminin 5, was abundant in Fut8(+/+) cells but was totally abolished in Fut8(-/-) cells, which was associated with the deficient migration mediated by alpha3beta1 integrin in Fut8(-/-) cells. Moreover integrin-mediated cell signaling was reduced in Fut8(-/-) cells. The reintroduction of Fut8 potentially restored laminin 5-induced migration and intracellular signaling. Collectively, these results suggested that core fucosylation is essential for the functions of alpha3beta1 integrin. 相似文献