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141.
Geographic isolation is widely viewed as a key component of insular radiations on islands. However, strong ecological affinities may also reinforce isolation and promote genetic divergence. The black fly fauna in the Society Islands French Polynesia is notable for the number of closely related endemic species (31), and the morphological and habitat diversity of the larvae. Here, we measure ecological and morphological differences within and between two closely related species, Simulium oviceps and Simulium dussertorum and relate these differences to genetic distance. Phylogenetic analyses of a 920 bp fragment of the cytochrome oxidase I (COI) gene revealed a well-supported, ecologically divergent S. oviceps clade (larvae found in rivers instead of cascades) that shows little morphological differentiation. For both S. oviceps and S. dussertorum, genetic distance among populations is related to larval habitat, with cascade populations showing greater isolation from each other than river populations. Our data support the hypothesis that larval ecological shifts have played a role in the radiation of this black fly fauna. 相似文献
142.
Hidaka M Su GN Chen JK Mukaisho K Hattori T Yamamoto G 《In vitro cellular & developmental biology. Animal》2007,43(2):49-58
Bone is a complex, highly structured, mechanically active, three-dimensional (3-D) tissue composed of cellular and matrix
elements. We previously published a report on in situ collagen gelation using a rotary 3-D culture system (CG–RC system) for
the construction of large tissue specimens. The objective of the current study was to evaluate the feasibility of bone tissue
engineering using our CG–RC system. Osteoblasts from the calvaria of newborn Wistar rats were cultured in the CG–RC system
for up to 3 wk. The engineered 3-D tissues were implanted into the backs of nude mice and calvarial round bone defects in
Wistar rats. Cell metabolic activity, mineralization, and bone-related proteins were measured in vitro in the engineered 3-D
tissues. Also, the in vivo histological features of the transplanted, engineered 3-D tissues were evaluated in the animal
models. We found that metabolic activity increased in the engineered 3-D tissues during cultivation, and that sufficient mineralization
occurred during the 3 wk in the CG–RC system in vitro. One mo posttransplantation, the transplants to nude mice remained mineralized
and were well invaded by host vasculature. Of particular interest, 2 mo posttransplantation, the transplants into the calvarial
bone defects of rats were replaced by new mature bone. Thus, this study shows that large 3-D osseous tissue could be produced
in vitro and that the engineered 3-D tissue had in vivo osteoinductive potential when transplanted into ectopic locations
and into bone defects. Therefore, this system should be a useful model for bone tissue engineering. 相似文献
143.
Ghosh JG Houck SA Clark JI 《The international journal of biochemistry & cell biology》2007,39(10):1804-1815
Molecular chaperones including the small heat shock proteins, alphaB crystallin and sHSP27 participate in the assembly, disassembly, and reorganization of the cytoskeleton during cell development and differentiation. While alphaB crystallin and sHSP27 stabilize and modulate filament assembly and re-organization, the sequences and structural domains mediating interactions between these proteins and filaments are unknown. It is important to define these interactive domains in order to understand differential interactions between chaperones and stable or unfolding filaments and their function in the cellular stress response. Protein pin arrays identified sequences in human alphaB crystallin that selectively interacted with native or partially unfolded filament proteins desmin, glial-fibrillary acidic protein, and actin. Circular dichroism spectroscopy determined differences in the structure of these filaments at 23 and 45 degrees C. Seven alphaB crystallin sequences had stronger interactions with desmin and six sequences had stronger interactions with glial-fibrillary acidic protein at 23 degrees C than at 45 degrees C. The alphaB crystallin sequences (33)LESDLFPTSTSLSPFYLRPPSFLR(56) and (129)DPLTITSSLSSDGV(145) had the strongest interactions with actin at 23 degrees C, while (57)APSWFDTG(64), (111)HGFISREF(118), (145)VNGPRKQVSG(154), and (155)PERTIPITREEK(165) had the strongest interactions with actin at 45 degrees C. The actin interactive sequences of alphaB crystallin overlapped with previously identified alphaB crystallin chaperone sequences and were synthesized to evaluate their effect on the assembly and aggregation of actin. Full-length alphaB crystallin and the core domain chaperone sequence (131)LTITSSLSSDGV(143) promoted actin polymerization at 37 degrees C and inhibited depolymerization and aggregation at 50 degrees C. The results support the hypothesis that interactive domains in alphaB crystallin have multiple functions in stabilizing the cytoskeleton and protecting cytosolic proteins from unfolding. 相似文献
144.
We report the effect of the natural polyphenolic compounds from green tea on the catalytic activity of Ribonuclease A (RNase A). The compounds behave as noncompetitive inhibitors of the protein with inhibition constants ranging from 80-1300 microM. The dissociation constants range from 50-150 microM for the RNase A-polyphenol complexes as determined by ultraviolet (UV) and circular dichroism (CD) studies. We have also investigated the changes in the secondary structure of RNase A on complex formation by CD and Fourier transformed infrared (FTIR) spectroscopy. The presence of the gallate moiety has been shown to be important for the inhibition of enzymatic activity. Docking studies for these compounds indicate that the preferred site of binding is the region encompassing residues 34-39 with possible hydrogen bonding with Lys 7 and Arg 10. Finally we have also looked at changes in the accessible surface area of the interacting residues on complex formation for an insight into the residues involved in the interaction. 相似文献
145.
Invasive plants that most threaten biodiversity are those that rapidly form a monospecific stand, like the clonal grass, Phalaris arundinacea. Understanding complex and potentially interacting factors that are common in urban and agricultural landscapes and underlie
rapid invasions requires an experimental, factorial approach. We tested the effects of flooding and nutrient and sediment
additions (3 × 3 × 3 = 27 treatments, plus a control with no additions) on invasion of Phalaris into mesocosms containing wet prairie vegetation. We discovered a three-step invasion and degradation process: (1) initially,
resident native species declined with prolonged flooding and sediment additions, and (2) prolonged flooding, sedimentation,
and nutrients accelerated Phalaris aboveground growth; biomass rose to 430 times that of the control within just two growing seasons. The dramatic expansion
of Phalaris in the second year resulted in the formation of monospecific stands in over one-third of the treatments, as (3) native species
continued their decline in year 2. Disturbances acted alone and in combination to make the resident wetland community more
invasible and Phalaris more aggressive, leading to monospecific stands. Yet, Phalaris did not always “win”: under the least disturbed conditions, the resident plant canopy remained dense and vigorous and Phalaris remained small. When anthropogenic disturbances coincide with increases in the gross supply of resources, more tolerant,
fast-growing, and morphologically plastic plants like Phalaris can invade very rapidly. The fluctuating resource hypothesis should thus be refined to consider the role of interacting disturbances
in facilitating invasions. 相似文献
146.
Bax Narissa Novaglio Camilla Maxwell Kimberley H. Meyers Koen McCann Joy Jennings Sarah Frusher Stewart Fulton Elizabeth A. Nursey-Bray Melissa Fischer Mibu Anderson Kelli Layton Cayne Emad Gholam Reza Alexander Karen A. Rousseau Yannick Lunn Zau Carter Chris G. 《Reviews in Fish Biology and Fisheries》2022,32(1):189-207
Reviews in Fish Biology and Fisheries - Humans have relied on coastal resources for centuries. However, current growth in population and increased accessibility of coastal resources through... 相似文献
147.
148.
149.
Joy Scaria Haruo Suzuki Christopher P. Ptak Jenn-Wei Chen Yongzhang Zhu Xiao-Kui Guo Yung-Fu Chang 《BMC genomics》2015,16(1)
Background
Clostridium difficile and C. sordellii are two anaerobic, spore forming, gram positive pathogens with a broad host range and the ability to cause lethal infections. Despite strong similarities between the two Clostridial strains, differences in their host tissue preference place C. difficile infections in the gastrointestinal tract and C. sordellii infections in soft tissues.Results
In this study, to improve our understanding of C. sordellii and C. difficile virulence and pathogenesis, we have performed a comparative genomic and phenomic analysis of the two. The global phenomes of C. difficile and C. sordellii were compared using Biolog Phenotype microarrays. When compared to C. difficile, C. sordellii was found to better utilize more complex sources of carbon and nitrogen, including peptides. Phenotype microarray comparison also revealed that C. sordellii was better able to grow in acidic pH conditions. Using next generation sequencing technology, we determined the draft genome of C. sordellii strain 8483 and performed comparative genome analysis with C. difficile and other Clostridial genomes. Comparative genome analysis revealed the presence of several enzymes, including the urease gene cluster, specific to the C. sordellii genome that confer the ability of expanded peptide utilization and survival in acidic pH.Conclusions
The identified phenotypes of C. sordellii might be important in causing wound and vaginal infections respectively. Proteins involved in the metabolic differences between C. sordellii and C. difficile should be targets for further studies aimed at understanding C. difficile and C. sordellii infection site specificity and pathogenesis.Electronic supplementary material
The online version of this article (doi:10.1186/s12864-015-1663-5) contains supplementary material, which is available to authorized users. 相似文献150.
Oestergaard MZ Inoue M Yoshida S Mahanani WR Gore FM Cousens S Lawn JE Mathers CD;United Nations Inter-Agency Group for Child Mortality Estimation the Child Health Epidemiology Reference Group 《PLoS medicine》2011,8(8):e1001080