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941.
Narumi Ogonuki Manami Mori Akie Shinmen Kimiko Inoue Keiji Mochida Akihiko Ohta Atsuo Ogura 《PloS one》2010,5(6)
Background
Intracytoplasmic sperm injection (ICSI) has been widely used to study the mechanisms of mammalian fertilization and to rescue male-factor infertility in humans and animals. However, very few systematic analyses have been conducted to define factors affecting the efficiency of ICSI. In this study, we undertook a large-scale series of ICSI experiments in mice to define the factors that might affect outcomes.Methodology/Principal Findings
We used a 5×3×2 factorial design with the following factors: mouse genotype (ICR, C57BL/6, DBA/2, C3H/He, and 129/Sv strains), type of male germ cells (epididymal sperm, elongated or round spermatids), and their freeze–thawing treatment. The efficiencies (parameters) of each developmental step were analyzed by three-way ANOVA (significance level P<0.01). The type of male germ cells affected all the four parameters observed: oocyte survival after injection, cleavage of oocytes, implantation, and birth of offspring. Genotype affected the oocyte survival, cleavage and birth rates, whereas freeze–thawing had no effects on any of the parameters. There were significant genotype/cell type interactions for oocyte survival and cleavage, indicating that they were determined by a combination of strain and germ cell maturity. Multiple comparisons revealed that spermatozoa and elongated spermatids gave better implantation and birth rates than did round spermatids, while spermatozoa and elongated spermatozoa were indistinguishable in their ability to support embryonic development. The best overall efficiency (birth rate per oocytes injected) was obtained with frozen–thawed DBA/2 strain elongated spermatids (23.2±4.2%).Conclusions/Significance
The present study provides the first comprehensive information on ICSI using the mouse as a model and will contribute to the efficient use of materials, time, and efforts in biomedical research and clinics involving ICSI. 相似文献942.
Osamu Kishida Geoffrey C. Trussell Akihiko Mougi Kinya Nishimura 《Population Ecology》2010,52(1):37-46
The outcome of species interactions is often strongly influenced by variation in the functional traits of the individuals
participating. A rather large body of work demonstrates that inducible morphological plasticity in predators and prey can
both influence and be influenced by species interaction strength, with important consequences for individual fitness. Much
of the past research in this area has focused on the ecological and evolutionary significance of trait plasticity by studying
single predator–prey pairs and testing the performance of individuals having induced and noninduced phenotypes. This research
has thus been critical in improving our understanding of the adaptive value of trait plasticity and its widespread occurrence
across species and community types. More recently, researchers have expanded this foundation by examining how the complexity
of organismal design and community-level properties can shape plasticity in functional traits. In addition, researchers have
begun to merge evolutionary and ecological perspectives by linking trait plasticity to community dynamics, with particular
attention on trait-mediated indirect interactions. Here, we review recent studies on inducible morphological plasticity in
predators and their prey with an emphasis on internal and external constraints and how the nature of predator–prey interactions
influences the expression of inducible phenotypes. In particular, we focus on multiple-trait plasticity, flexibility and modification
of inducible plasticity, and reciprocal plasticity between predator and prey. Based on our arguments on these issues, we propose
future research directions that should better integrate evolutionary and population studies and thus improve our understanding
of the role of phenotypic plasticity in predator–prey population and community dynamics. 相似文献
943.
Konoeda F Shichita T Yoshida H Sugiyama Y Muto G Hasegawa E Morita R Suzuki N Yoshimura A 《Biochemical and biophysical research communications》2010,402(3):500-506
Recently, T cell cytokines such as IL-17 and IFN-γ have been shown to play important roles in the progression of brain injury induced by ischemia. We have shown that IL-23 from infiltrated macrophages activates γδT cells, thereby inducing IL-17 from these cells. However, deletion of the IL-23 gene in mice showed a more dramatic protective effect against brain ischemia reperfusion (I/R) model than γδT cell depletion did, suggesting that IL-23 plays some other pivotal role in brain injury in addition to its role in IL-17 induction. To develop therapeutic methods based on these findings, we examined the effect of the JAK kinase inhibitor CP-690550 and an anti-IL12/23 monoclonal antibody on an I/R model. CP-690550 efficiently inhibited IL-17 production from memory T cells in vitro and partly suppressed infarct volume increase after I/R. Anti-p40 antibody, which blocks both IL-12 and IL-23, efficiently suppressed I/R injury and improved recovery of neurological deficits. The number of IL-17-producing cells was decreased by anti-p40 antibody treatment. Thus the JAK inhibitor and anti-p40 antibody, both of which have already been under trial for the treatment of several human inflammatory diseases, appear to be promising therapeutic agents for the amelioration of stroke. 相似文献
944.
945.
Babiker M. A. Abdel-Banat Hisashi Hoshida Akihiko Ano Sanom Nonklang Rinji Akada 《Applied microbiology and biotechnology》2010,85(4):861-867
The process of ethanol fermentation has a long history in the production of alcoholic drinks, but much larger scale production
of ethanol is now required to enable its use as a substituent of gasoline fuels at 3%, 10%, or 85% (referred to as E3, E10,
and E85, respectively). Compared with fossil fuels, the production costs are a major issue for the production of fuel ethanol.
There are a number of possible approaches to delivering cost-effective fuel ethanol production from different biomass sources,
but we focus in our current report on high-temperature fermentation using a newly isolated thermotolerant strain of the yeast
Kluyveromyces marxianus. We demonstrate that a 5°C increase only in the fermentation temperature can greatly affect the fuel ethanol production costs.
We contend that this approach may also be applicable to the other microbial fermentations systems and propose that thermotolerant
mesophilic microorganisms have considerable potential for the development of future fermentation technologies. 相似文献
946.
Background
Large nucleotide sequence datasets are becoming increasingly common objects of comparison. Complete bacterial genomes are reported almost everyday. This creates challenges for developing new multiple sequence alignment methods. Conventional multiple alignment methods are based on pairwise alignment and/or progressive alignment techniques. These approaches have performance problems when the number of sequences is large and when dealing with genome scale sequences. 相似文献947.
Chung SH Seki K Choi BI Kimura KB Ito A Fujikado N Saijo S Iwakura Y 《Arthritis research & therapy》2010,12(5):R188
Introduction
Chemokines and their receptors are potential therapeutic targets in rheumatoid arthritis (RA). Among these, several studies suggested the involvement of CXC chemokine 4 (CXCR4) and its ligand CXC ligand 12 (SDF-1) in RA pathogenesis. However, the role of these molecules in T-cell function is not known completely because of embryonic lethality of Cxcr4- and Cxcl12- deficient mice. In this report, we generated T cell-specific Cxcr4 -deficient mice and showed that the CXCR4 in T cells is important for the development of collagen-induced arthritis (CIA). 相似文献948.
The abilities of some ascomycetes (Myxotrichaceae) from a Sphagnum bog in Alberta to degrade cellulose, phenolics, and Sphagnum tissue were compared with those of two basidiomycetes. Most Myxotrichaceae degraded cellulose and tannic acid, and removed cell-wall components simultaneously from Sphagnum tissues, whereas the basidiomycetes degraded cellulose and insoluble phenolics, and preferentially removed the polyphenolic matrix from Sphagnum cell walls. Mass losses from Sphagnum varied from up to 50% for some ascomycetes to a maximum of 35% for the basidiomycetes. The decomposition of Sphagnum by the Myxotrichaceae was analogous to the white rot of wood and indicates that these fungi have the potential to cause significant mineralization of carbon in bogs. 相似文献
949.
Shishido T Muraoka M Ueda M Seno M Tanizawa K Kuroda S Fukuda H Kondo A 《Applied microbiology and biotechnology》2006,73(3):505-511
Bionanocapsules (BNCs) are hollow nanoscale particles composed of L protein of the hepatitis B virus surface antigen that represent specific affinity for human hepatocytes. BNCs can transfer genes and drugs into human hepatocytes efficiently and specifically. BNC can be expressed in yeast cells. In this study, we developed a new L particle production system using a stably transfected insect cell line. For this purpose, we established a host–vector system using the Trichoplusia ni insect cell line. L particles were efficiently secreted by the overexpression of the L protein, which was fused to the secretion signal peptide. The concentration of L particles was reached approximately 1.7 μg/ml in 5 days during cultivation in a serum-free medium without antibiotic selective pressure. The production of L particles was maintained for at least 75 days. The secretory production of L particles facilitated their easy purification by chromatography. Furthermore, it was demonstrated that purified L particles can transfect only human hepatocytes. Therefore, an insect cell expression system is an attractive tool for the production of BNC. 相似文献
950.
Clostridium cellulovorans degrades cellulose efficiently to small oligosaccharides, which are used as an energy source. To characterize enzymes related to degrading small oligosaccharides, a gene was cloned for an extracellular non-cellulosomal beta-glucan glucohydrolase (BglA) classified as a family-1 glycosyl hydrolase in C. cellulovorans. Recombinant BglA (rBglA) had higher activity on long glucooligomers than on cellobiose. When cellulosomes and rBglA were incubated with cellulose, the oligosaccharides produced were degraded more effectively to cellobiose and glucose, than with cellulosomes alone, indicating that BglA facilitated the degradation of accessible cello-oligosaccharides produced from cellulose by C. cellulovorans cellulosomes. Thus, this is an example of an extracellular non-cellulosomal enzyme working in a cooperative manner with cellulosomes to degrade cellulose to sugars. 相似文献