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981.
Min-Jung Lee Sooyeon Jang Minyeop Nahm Jin-Ho Yoon Seungbok Lee 《Molecules and cells》2013,36(2):163-168
Members of the Tre-2/Bub2/Cdc16 (TBC) family of proteins are believed to function as GTPase-activating proteins (GAPs) for Rab GTPases, which play pivotal roles in intracellular membrane trafficking. Although membrane trafficking is fundamental to neuronal morphogenesis and function, the roles of TBC-family Rab GAPs have been poorly characterized in the nervous system. In this paper, we provide genetic evidence that Tbc1d15–17, the Drosophila homolog of mammalian Rab7-GAP TBC1d15, is required for normal presynaptic growth and postsynaptic organization at the neuromuscular junction (NMJ). A loss-of-function mutation in Tbc1d15–17 or its presynaptic knockdown leads to an increase in synaptic bouton number and NMJ length. Tbc1d15–17 mutants are also defective in the distribution of the postsynaptic scaffold Discs-large (Dlg) and in the level of the postsynaptic glutamate subunit GluRIIA. These postsynaptic phenotypes are recapitulated by postsynaptic knockdown of Tbc1d15–17. We also show that presynaptic overexpression of a constitutively active Rab7 mutant in a wild-type background causes a synaptic overgrowth phenotype resembling that of Tbc1d15–17 mutants, while a dominant-negative form of Rab7 has the opposite effect. Together, our findings establish a novel role for Tbc1d15–17 and its potential substrate Rab7 in regulating synaptic development. 相似文献
982.
983.
Jaeseok Park Kyoung‐Pil Lee Hyeonji Kim Sungjo Park Ruchire E. Wijesinghe Jaeyul Lee Sangyeob Han Sangbong Lee Pilun Kim Dong‐Woo Cho Jinah Jang Hong K. Kim Mansik Jeon Jeehyun Kim 《Journal of biophotonics》2019,12(11)
Corneal transplantation by full‐thickness penetrating keratoplasty with human donor tissue is a widely accepted treatment for damaged or diseased corneas. Although corneal transplantation has a high success rate, a shortage of high‐quality donor tissue is a considerable limitation. Therefore, bioengineered corneas could be an effective solution for this limitation, and a decellularized extracellular matrix comprises a promising scaffold for their fabrication. In this study, three‐dimensional bioprinted decellularized collagen sheets were implanted into the stromal layer of the cornea of five rabbits. We performed in vivo noninvasive monitoring of the rabbit corneas using swept‐source optical coherence tomography (OCT) after implanting the collagen sheets. Anterior segment OCT images and averaged amplitude‐scans were acquired biweekly to monitor corneal thickness after implantation for 1 month. The averaged cornea thickness in the control images was 430.3 ± 5.9 μm, while the averaged thickness after corneal implantation was 598.5 ± 11.8 μm and 564.5 ± 12.5 μm at 2 and 4 weeks, respectively. The corneal thickness reduction of 34 μm confirmed the biocompatibility through the image analysis of the depth‐intensity profile base. Moreover, hematoxylin and eosin staining supported the biocompatibility evaluation of the bioprinted decellularized collagen sheet implantation. Hence, the developed bioprinted decellularized collagen sheets could become an alternative solution to human corneal donor tissue, and the proposed image analysis procedure could be beneficial to confirm the success of the surgery. 相似文献
984.
985.
Otoliths were used for the first time to successfully validate the age of members of the family Syngnathidae: the spotted pipefish Stigmatopora argus and the wide-bodied pipefish Stigmatopora nigra. Otolith increments were deposited daily in (1) known-age juveniles ranging in age from 0 to 31 days and (2) adults that had been stained with alizarin complexone, and a hatch mark was found on all otoliths which represented day 0. Otolith increment validation will allow development of growth models for S. argus and S. nigra, essential to understanding and managing these exclusive seagrass species. 相似文献
986.
Soo Hyung Eo Woo-Shin Lee Travis C. Glenn Kenneth L. Jones Eun-Jae Lee Yong-Su Park John P. Carroll Shin-Jae Rhim 《Conservation Genetics》2009,10(6):1923-1925
We isolated and characterized eight polymorphic microsatellite DNA markers from the Korean field mouse, Apodemus peninsulae. The primers developed in this study yielded an average polymorphic information content of 0.78 (range 0.44–0.90), with an
average of 10.9 alleles per locus (range 5–16). Observed and expected heterozygosities ranged from 0.46 to 1.00 and from 0.49
to 0.93, respectively. These polymorphic loci may provide useful tools for understanding the species’ genetic structure and
ecology. 相似文献
987.
M. Lee Nelson Thomas E. McMahon Russell F. Thurow 《Environmental Biology of Fishes》2002,64(1-3):321-332
Large-bodied, migratory life history forms of bull charr, Salvelinus confluentus, were historically abundant in northwestern North America, but many remaining populations of this now-threatened species presently persist as small-bodied residents isolated in headwater streams. We examined whether the migratory form has been lost from headwater populations of bull charr and their potential for re-establishment. Upstream and downstream movement of bull charr and other salmonids from three tributary populations in the Bitterroot River drainage, Montana, was measured with weirs over a 17-month period. The migratory life history was rare or absent in two tributaries but still present at a low level in a third. In contrast, substantial numbers (n = 1745) of juvenile and adults of other salmonids (brown trout, Salmo trutta, cutthroat trout, Oncorhynchus clarki, and mountain whitefish, Prosopium williamsoni) were captured near tributary mouths, indicating a migratory life history was common in other species. Apparent decline of the migratory life history in bull charr was not directly related to damming suggesting other downstream mortality factors (predation, temperature) also are involved. Isolated, nonmigratory forms have increased risk of extinction, and restoration of the population connectivity via the re-establishment of migratory stocks is an important conservation goal for bull charr recovery. However, the factors governing migratory tendency remain unclear. 相似文献
988.
U Varshney C P Lee B L Seong U L RajBhandary 《The Journal of biological chemistry》1991,266(27):18018-18024
We describe the effect of mutations in the acceptor stem of Escherichia coli initiator tRNA on its function in vivo. The acceptor stem mutations were coupled to mutations in the anticodon sequence from CAU----CUA to allow functional studies on the mutant tRNAs in initiation and in elongation in vivo. We show that, with one exception, there is a good correlation between the kinetic parameters for formylation of the mutant tRNAs in vitro (preceding paper, Lee, C.P., Seong, B. L., and RajBhandary, U.L. (1991) J. Biol. Chem. 266, 18012-18017) and their activity in initiation in vivo. These results suggest an important role for formylation of initiator tRNA in its function in initiation, at least when it is aminoacylated with glutamine as is the case with the mutant tRNAs used here. Mutant tRNAs that have a base pair between nucleotides 1 and 72 at the top of the acceptor stem function as elongators, as analyzed by their ability to suppress an amber mutation in the E. coli beta-galactosidase gene. One of these mutants is also quite active in initiation. Thus, activities of a tRNA in initiation and elongation steps of protein synthesis are not mutually exclusive. Using a mRNA with two in frame UAG codons, we show that this mutant tRNA can both initiate protein synthesis from the upstream UAG and suppress the down-stream UAG. We discuss the potential use of tRNAs with such "dual" functions in tightly regulated expression of genes for proteins in E. coli. 相似文献
989.
990.