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121.
Mechanical forces are an important contributor to cell fate specification and cell migration during embryonic development in animals. Similarities between embryogenesis and regeneration, particularly with regards to pattern formation and large-scale tissue movements, suggest similarly important roles for physical forces during regeneration. While the influence of the mechanical environment on stem cell differentiation in vitro is being actively exploited in the fields of tissue engineering and regenerative medicine, comparatively little is known about the role of stresses and strains acting during animal regeneration. In this review, we summarize published work on the role of physical principles and mechanical forces in animal regeneration. Novel experimental techniques aimed at addressing the role of mechanics in embryogenesis have greatly enhanced our understanding at scales from the subcellular to the macroscopic – we believe the time is ripe for the field of regeneration to similarly leverage the tools of the mechanobiological research community. 相似文献
122.
Fu‐Jin Wei Lin‐Yun Kuang Hui‐Min Oung Sin‐Yuan Cheng Hshin‐Ping Wu Lin‐Tzu Huang Yi‐Tzu Tseng Wan‐Yi Chiou Vicki Hsieh‐Feng Cheng‐Han Chung Su‐May Yu Lan‐Ying Lee Stanton B. Gelvin Yue‐Ie C. Hsing 《The Plant journal : for cell and molecular biology》2016,85(5):648-659
Rice (Oryza sativa) is one of the world's most important crops. Rice researchers make extensive use of insertional mutants for the study of gene function. Approximately half a million flanking sequence tags from rice insertional mutant libraries are publicly available. However, the relationship between genotype and phenotype is very weak. Transgenic plant assays have been used frequently for complementation, overexpression or antisense analysis, but sequence changes caused by callus growth, Agrobacterium incubation medium, virulence genes, transformation and selection conditions are unknown. We used high‐throughput sequencing of DNA from rice lines derived from Tainung 67 to analyze non‐transformed and transgenic rice plants for mutations caused by these parameters. For comparison, we also analyzed sequence changes for two additional rice varieties and four T‐DNA tagged transformants from the Taiwan Rice Insertional Mutant resource. We identified single‐nucleotide polymorphisms, small indels, large deletions, chromosome doubling and chromosome translocations in these lines. Using standard rice regeneration/transformation procedures, the mutation rates of regenerants and transformants were relatively low, with no significant differences among eight tested treatments in the Tainung 67 background and in the cultivars Taikeng 9 and IR64. Thus, we could not conclusively detect sequence changes resulting from Agrobacterium‐mediated transformation in addition to those caused by tissue culture‐induced somaclonal variation. However, the mutation frequencies within the two publically available tagged mutant populations, including TRIM transformants or Tos17 lines, were about 10‐fold higher than the frequency of standard transformants, probably because mass production of embryogenic calli and longer callus growth periods were required to generate these large libraries. 相似文献
123.
K F Huang L P Chow S H Chiou 《Biochemical and biophysical research communications》1999,263(3):610-616
A proteinase inhibitor (designated as TMI) was isolated and purified from the snake serum of Taiwan habu (Trimeresurus mucrosquamatus) by using successive chromatographies which included Sephadex G-100, DEAE-Sephacel chromatographies, and C(4) reverse-phase HPLC. The purified inhibitor was shown to be a homogeneous protein with a molecular mass of about 47 or 36 kDa in the presence or absence of a reducing agent, beta-mercaptoethanol. The inhibitor decreases in molecular mass by about 23% with N-linked neuraminidase treatment, suggesting that it is a glycoprotein. Further enzymatic analyses indicated that this inhibitor possesses strong inhibitory activities toward three zinc-dependent metalloproteinases and not fibrinogenolytic serine proteases previously isolated from the venom of the same snake species with an IC(50) of about 0.2-1.1 microM. Its IC(50) value was approximately three orders of magnitude more effective than those of the tripeptide inhibitors we previously purified from the crude venom of the same snake (Biochem. Biophys. Res. Commun. 248, 562-568 (1998)). The purified inhibitor showed stronger inhibitory action against caseinolytic activities of crude venoms from closely related species of Taiwan habu than those from unrelated species. N-terminal sequence analysis showed that its sequence is distinctly different from sequences of those serum inhibitors reported for other snake species in the literature. Based on inhibition susceptibility and primary structures of various snake protease inhibitors, it is suggested that this novel inhibitor isolated from the serum of Taiwan habu may be a unique self-defense protein factor mainly for protection against envenomation from snakes of the same genus. 相似文献
124.
Lucas R Lopes Vitor AR Miranda Rodrigo A Goes Gabriel GA Souza Giuliana R Souza Jessica CS Rocha Victor RA Cossich Jamila A Perini 《Biology of sport / Institute of Sport》2021,38(4):703
The COVID-19 pandemic has presented significant challenges and implications for the sports community. Thus, this study aimed to describe the prevalence of COVID-19 in Brazilian athletes and identify the epidemiological, clinical, athletic, life and health factors associated with the disease in these individuals. A cross-sectional study was performed involving 414 athletes from 22 different sports using an online questionnaire from August to November 2020. The association between the athletes’ characteristics and COVID-19 was evaluated using a logistic regression model. The prevalence of COVID-19 was 8.5%, although only 40% of athletes reported having been tested. Being under 27 years of age (3-fold), having children (~5-fold), having a teammate test positive for COVID-19 (2.5-fold), and smoking (14-fold) were associated with a possible higher risk of disease. Almost 20% of athletes self-reported musculoskeletal injuries during the period of the pandemic that was studied. Athletes with a university education (P = 0.02), a profession other than sports (P < 0.001), those from a low-income family (P = 0.01), and public health system users (P = 0.04) were significantly less frequently tested for COVID-19, whereas international competitors, athletes who received a wage, and athletes who had a teammate who tested positive for COVID-19 were 2-, 3-, and 15-fold more likely to be tested for COVID-19, respectively. Approximately 26% of the athletes who tested negative or were untested reported more than three characteristic COVID-19 symptoms, and 11% of athletes who tested positive for COVID-19 were asymptomatic. The identification of modifiable (have children, smoking, and teammates positively tested) and non-modifiable (age under 27 years) factors related to COVID-19 in athletes can contribute to implementing surveillance programmes to decrease the incidence of COVID-19 in athletes and its negative impacts in sports. 相似文献
125.
126.
Biotic communities of freshwater marshes and mangroves in relation to saltwater incursions: implications for wetland regulation 总被引:3,自引:0,他引:3
Hsing-Juh Lin Kwang-Tsao Shao Wen-Liang Chiou Can-Jen W Maa Hwey-Lian Hsieh Wen-Lung Wu Lucia L. Severinghaus Yu-Tzu Wang 《Biodiversity and Conservation》2003,12(4):647-665
An ecosystem-level study was conducted in the Guandu wetlands insubtropical coastal Taiwan to examine how salinity influences the abundance,diversity, and structure of biotic communities. We surveyed eight permanentstudy sites, spanning freshwater marshes, to the gate on the dyke, andmesohaline mangroves representing a gradient of the extent of saltwaterincursions. Analyses of abiotic variables showed that salinity was the primarydetermining factor for discriminating habitat types in the wetlands, butcommunities differed in their sensitivity to salinity. The composition of plantand insect communities was most affected by the salinity gradient, suggestingthe utility of these communities for ecological monitoring of saltwaterincursions. However, spatial changes in communities at higher trophic levels,including macrobenthos, mollusks, fish, and birds, could not be explained simplyby the salinity gradient. Instead, changes in these communities were morerelevant to the composition of other biotic communities. Our results show thatspecies richness and diversity of plant communities were higher in the marshesthan in the mangroves. Nevertheless, insect communities censused in themangroves had higher diversity, despite lower abundance and species richness.Macrobenthos surveyed in the mangroves showed higher biomass and number of taxa.Mollusks and fish were also more abundant at sites near the gate compared to themarsh sites. This suggests that maintaining a tidal flux by means of gateregulation is necessary for conserving the spatial heterogeneity andbiodiversity of coastal wetlands. 相似文献
127.
Albert Chiou Angel Orte Paul D. Dunne Susanna Karlsson-Li David Klenerman 《Biophysical journal》2009,97(8):2306-2315
Neuroserpin is a member of the serine proteinase inhibitor superfamily. It can undergo a conformational transition to form polymers that are associated with the dementia familial encephalopathy with neuroserpin inclusion bodies and the wild-type protein can inhibit the toxicity of amyloid-β peptides in Alzheimer's disease. We have used a single molecule fluorescence method, two color coincidence detection, to determine the rate-limiting steps of the early stages of the polymerization of fluorophore-labeled neuroserpin and have assessed how this process is altered in the presence of Aβ1-40. Our data show that neuroserpin polymerization proceeds first by the unimolecular formation of an active monomer, followed by competing processes of both polymerization and formation of a latent monomer from the activated species. These data are not in keeping with the recently proposed domain swap model of polymer formation in which the latent species and activated monomer are likely to be formed by competing pathways directly from the unactivated monomeric serpin. Moreover, the Aβ1-40 peptide forms a weak complex with neuroserpin (dissociation constant of 10 ± 5 nM) that increases the amount of active monomer thereby increasing the rate of polymerization. The Aβ1-40 is displaced from the complex so that it acts as a catalyst and is not incorporated into neuroserpin polymers. 相似文献
128.
129.
Chien-Chang Chiu Jin-Chuan Sheu Chien-Hung Chen Cha-Ze Lee Ling-Ling Chiou Shiu-Huey Chou Guan-Tarn Huang Hsuan-Shu Lee 《Histochemistry and cell biology》2009,132(5):479-489
Liver progenitors, so-called oval cells, proliferate remarkably from periportal areas after severe liver injury when hepatocyte
regeneration is compromised. These cells invade far into the liver parenchyma. Molecular mechanisms underlying these behaviors
of oval cells remain poorly understood. In this study, we treated rats with 2-acetylaminofluorene/carbon tetrachloride to
induce hepatic oval cells. By expression microarray analysis, we investigated global gene expression profiles in liver tissue,
with an emphasis on adhesion molecules, extracellular matrix proteins, matrix metalloproteinases (MMPs), growth factors/cytokines,
and receptors that might contribute to the distinct behaviors of oval cells. Genes upregulated at least twofold were selected.
We then performed immunostaining to verify the microarray results and identified expression of MMP-7 and CD44 in oval cells.
Staining of cytokeratin (CK)-19, an oval-cell marker, was similar between oval cells located next to periportal areas and
those located far within the parenchyma. In contrast, CD44 staining was more intense in the parenchyma than in periportal
areas, suggesting a role of CD44 in oval-cell invasion. Moreover, newly differentiated CK-19+ hepatocytes within foci did not show CD44 staining, suggesting that CD44 is related to the undifferentiated oval-cell phenotype.
We then investigated oval-cell reactivity in CD44-deficient mice fed an oval cell-inducing diet of 3,5-diethoxycarbonyl-1,4-dihydrocollidine.
Results showed significantly reduced oval-cell reactivity in CD44-deficient mice. Thus, oval cells express MMP-7 and CD44,
and CD44 appears to play critical roles in the proliferation, invasion, and differentiation of hepatic oval cells in rodents. 相似文献
130.
Chi-Yuan Chen Shih-Hwa Chiou Chih-Yang Huang Chia-Ing Jan Shu-Chun Lin Ming-Long Tsai Jeng-Fan Lo 《Journal of biomedical science》2009,16(1):100-11
The progression and metastasis of solid tumors, including head and neck squamous cell carcinoma (HNSCC), have been related to the behavior of a small subpopulation of cancer stem cells. Here, we have established a highly malignant HNSCC cell line, SASVO3, from primary tumors using three sequential rounds of xenotransplantation. SASVO3 possesses enhanced tumorigenic ability both in vitro and in vivo. Moreover, SASVO3 exhibits properties of cancer stem cells, including that increased the abilities of sphere-forming, the number of side population cells, the potential of transplanted tumor growth and elevated expression of the stem cell marker Bmi1. Injection of SASVO3 into the tail vein of nude mice resulted in lung metastases. These results are consistent with the postulate that the malignant and/or metastasis potential of HNSCC cells may reside in a stem-like subpopulation. 相似文献