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result(s) for
"Kim, Jaehyoung"
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Individuality in gut microbiota composition is a complex polygenic trait shaped by multiple environmental and host genetic factors
by
Legge, Ryan
,
Hua, Kunjie
,
Kim, Jaehyoung
in
Animals
,
Bacteria - classification
,
Bacteria - genetics
2010
In vertebrates, including humans, individuals harbor gut microbial communities whose species composition and relative proportions of dominant microbial groups are tremendously varied. Although external and stochastic factors clearly contribute to the individuality of the microbiota, the fundamental principles dictating how environmental factors and host genetic factors combine to shape this complex ecosystem are largely unknown and require systematic study. Here we examined factors that affect microbiota composition in a large (n = 645) mouse advanced intercross line originating from a cross between C57BL/6J and an ICR-derived outbred line (HR). Quantitative pyrosequencing of the microbiota defined a core measurable microbiota (CMM) of 64 conserved taxonomic groups that varied quantitatively across most animals in the population. Although some of this variation can be explained by litter and cohort effects, individual host genotype had a measurable contribution. Testing of the CMM abundances for cosegregation with 530 fully informative SNP markers identified 18 host quantitative trait loci (QTL) that show significant or suggestive genomewide linkage with relative abundances of specific microbial taxa. These QTL affect microbiota composition in three ways; some loci control individual microbial species, some control groups of related taxa, and some have putative pleiotropic effects on groups of distantly related organisms. These data provide clear evidence for the importance of host genetic control in shaping individual microbiome diversity in mammals, a key step toward understanding the factors that govern the assemblages of gut microbiota associated with complex diseases.
Journal Article
The Evolution of Host Specialization in the Vertebrate Gut Symbiont Lactobacillus reuteri
by
Pearson, Bruce M.
,
Frese, Steven A.
,
Hauser, Loren
in
Animals
,
BASIC BIOLOGICAL SCIENCES
,
BIOLOGY
2011
Recent research has provided mechanistic insight into the important contributions of the gut microbiota to vertebrate biology, but questions remain about the evolutionary processes that have shaped this symbiosis. In the present study, we showed in experiments with gnotobiotic mice that the evolution of Lactobacillus reuteri with rodents resulted in the emergence of host specialization. To identify genomic events marking adaptations to the murine host, we compared the genome of the rodent isolate L. reuteri 100-23 with that of the human isolate L. reuteri F275, and we identified hundreds of genes that were specific to each strain. In order to differentiate true host-specific genome content from strain-level differences, comparative genome hybridizations were performed to query 57 L. reuteri strains originating from six different vertebrate hosts in combination with genome sequence comparisons of nine strains encompassing five phylogenetic lineages of the species. This approach revealed that rodent strains, although showing a high degree of genomic plasticity, possessed a specific genome inventory that was rare or absent in strains from other vertebrate hosts. The distinct genome content of L. reuteri lineages reflected the niche characteristics in the gastrointestinal tracts of their respective hosts, and inactivation of seven out of eight representative rodent-specific genes in L. reuteri 100-23 resulted in impaired ecological performance in the gut of mice. The comparative genomic analyses suggested fundamentally different trends of genome evolution in rodent and human L. reuteri populations, with the former possessing a large and adaptable pan-genome while the latter being subjected to a process of reductive evolution. In conclusion, this study provided experimental evidence and a molecular basis for the evolution of host specificity in a vertebrate gut symbiont, and it identified genomic events that have shaped this process.
Journal Article
Resistant Starches Types 2 and 4 Have Differential Effects on the Composition of the Fecal Microbiota in Human Subjects
2010
To systematically develop dietary strategies based on resistant starch (RS) that modulate the human gut microbiome, detailed in vivo studies that evaluate the effects of different forms of RS on the community structure and population dynamics of the gut microbiota are necessary. The aim of the present study was to gain a community wide perspective of the effects of RS types 2 (RS2) and 4 (RS4) on the fecal microbiota in human individuals.
Ten human subjects consumed crackers for three weeks each containing either RS2, RS4, or native starch in a double-blind, crossover design. Multiplex sequencing of 16S rRNA tags revealed that both types of RS induced several significant compositional alterations in the fecal microbial populations, with differential effects on community structure. RS4 but not RS2 induced phylum-level changes, significantly increasing Actinobacteria and Bacteroidetes while decreasing Firmicutes. At the species level, the changes evoked by RS4 were increases in Bifidobacterium adolescentis and Parabacteroides distasonis, while RS2 significantly raised the proportions of Ruminococcus bromii and Eubacterium rectale when compared to RS4. The population shifts caused by RS4 were numerically substantial for several taxa, leading for example, to a ten-fold increase in bifidobacteria in three of the subjects, enriching them to 18-30% of the fecal microbial community. The responses to RS and their magnitudes varied between individuals, and they were reversible and tightly associated with the consumption of RS.
Our results demonstrate that RS2 and RS4 show functional differences in their effect on human fecal microbiota composition, indicating that the chemical structure of RS determines its accessibility by groups of colonic bacteria. The findings imply that specific bacterial populations could be selectively targeted by well designed functional carbohydrates, but the inter-subject variations in the response to RS indicates that such strategies might benefit from more personalized approaches.
Journal Article
How Ethical Leadership Cultivates Innovative Work Behaviors in Employees? Psychological Safety, Work Engagement and Openness to Experience
by
Huang, Yan
,
Kim, Jaehyoung
,
Liu, Xin
in
Beliefs, opinions and attitudes
,
Competitive advantage
,
Employees
2023
In this study, social exchange theory and social learning theory are integrated to explain how and when ethical leaders promote innovative work behaviors among employees. Specifically, this research developed a moderated mediation model to examine the mediating effect of psychological safety and work engagement and the moderating effect of openness to experience. The survey data were collected from 397 full-time employees of various service industry companies operating in China in two stages with a two-week gap. SPSS and AMOS were used to assess the study hypotheses. First, SPSS 22.0 was used to test the reliability of variables and conduct descriptive statistics, correlation, and regression analysis, and AMOS 22.0 was used to conduct confirmatory factor analysis. Second, Version 22 of SPSS and the PROCESS macro were used to analyze mediation, moderation, and conditional process effects. The results indicated that ethical leadership was positively related to employees’ innovative work behavior. Ethical leadership significantly positively affects employees’ innovative work behaviors by mediating psychological safety and work engagement. Moreover, the results showed that openness to experience plays a moderating effect in the positive relationship between work engagement and employees’ innovative work behavior. Finally, openness to experience moderates the indirect relationship (via work engagement) between ethical leadership and employees’ innovative work behavior. This research contributes to the existing literature on ethical leadership and provides a reference for companies to stimulate employees’ innovative work behavior.
Journal Article
Bile-acid-mediated decrease in endoplasmic reticulum stress: a potential contributor to the metabolic benefits of ileal interposition surgery in UCD-T2DM rats
by
Giulivi, Cecilia
,
Haj, Fawaz G.
,
Jelsing, Jacob
in
Adipocytes - drug effects
,
Adipocytes - metabolism
,
Animals
2013
Post-operative increases in circulating bile acids have been suggested to contribute to the metabolic benefits of bariatric surgery; however, their mechanistic contributions remain undefined. We have previously reported that ileal interposition (IT) surgery delays the onset of type 2 diabetes in UCD-T2DM rats and increases circulating bile acids, independently of effects on energy intake or body weight. Therefore, we investigated potential mechanisms by which post-operative increases in circulating bile acids improve glucose homeostasis after IT surgery. IT, sham or no surgery was performed on 2-month-old weight-matched male UCD-T2DM rats. Animals underwent an oral fat tolerance test (OFTT) and serial oral glucose tolerance tests (OGTT). Tissues were collected at 1.5 and 4.5 months after surgery. Cell culture models were used to investigate interactions between bile acids and ER stress. IT-operated animals exhibited marked improvements in glucose and lipid metabolism, with concurrent increases in postprandial glucagon-like peptide-1 (GLP-1) secretion during the OFTT and OGTTs, independently of food intake and body weight. Measurement of circulating bile acid profiles revealed increases in circulating total bile acids in IT-operated animals, with a preferential increase in circulating cholic acid concentrations. Gut microbial populations were assessed as potential contributors to the increases in circulating bile acid concentrations, which revealed proportional increases in Gammaproteobacteria in IT-operated animals. Furthermore, IT surgery decreased all three sub-arms of ER stress signaling in liver, adipose and pancreas tissues. Amelioration of ER stress coincided with improved insulin signaling and preservation of β-cell mass in IT-operated animals. Incubation of hepatocyte, adipocyte and β-cell lines with cholic acid decreased ER stress. These results suggest that post-operative increases in circulating cholic acid concentration contribute to improvements in glucose homeostasis after IT surgery by ameliorating ER stress.
Journal Article
Octamer-based genome scanning distinguishes a unique subpopulation of Escherichia coli O157:H7 strains in cattle
1999
Multilocus-genotyping methods have shown that Escherichia coli O157:H7 is a geographically disseminated clone. However, high-resolution methods such as pulse-field gel electrophoresis demonstrate significant genomic diversity among different isolates. To assess the genetic relationship of human and bovine isolates of E. coli O157:H7 in detail, we have developed an octamer-based genome-scanning methodology, which compares the distance between over-represented, strand-biased octamers that occur in the genome. Comparison of octamer-based genome-scanning products derived from >1 megabase of the genome demonstrated the existence of two distinct lineages of E. coli O157:H7 that are disseminated within the United States. Human and bovine isolates are nonrandomly distributed among the lineages, suggesting that one of these lineages may be less virulent for humans or may not be efficiently transmitted to humans from bovine sources. Restriction fragment length polymorphism analysis with lambdoid phage genomes indicates that phage-mediated events are associated with divergence of the lineages, thereby providing one explanation for the degree of diversity that is observed among E. coli O157:H7 by other molecular-fingerprinting methods.
Journal Article
Effects of Idiosyncratic Deals, Psychological Contract, Job Satisfaction and Environmental Turbulence on Unethical Pro-Organizational Behavior
by
Huang, Yan
,
Kim, Jaehyoung
,
Liu, Xin
in
Beliefs, opinions and attitudes
,
Business ethics
,
Contract negotiations
2022
Corporate ethics is an important part of corporate sustainable development. Sustainability is not only about the environment but also about the well-being of employees, including job satisfaction (JS), the Psychological contract (PC), etc. Among them, to organize relationships with other stakeholders, the unethical pro-organizational behavior (UPB) of employees not only damages the corporate image and reputation but even threatens the sustainable development of the enterprise. In this context, the influencing factors that induce UPB should be analyzed and considered. Based on social exchange theory and social cognitive theory, this research explores how idiosyncratic deals (I-deals) affect employees’ intention to perform UPB through the PC and JS from the viewpoint of employee-organization relationships, and the moderating role of environmental turbulence in it. The research sample was drawn from 377 employees working in China, manufacturing companies. The questionnaire was distributed at two time points. In the first questionnaire, the employees who participated in the survey answered information such as idiosyncratic deals, the PC, JS and environmental turbulence (ET). After 1 month, employees responded to UPB messages. The research hypotheses were tested analytically using SPSS 23.0 and Amos 23.0. The survey showed that I-deals had a beneficial impact on UPB. The psychological contract and JS also mediated the influence on I-deals on UPB. The positive relationship between I-deals and UPB through the chain mediated effect of PC and JS. Moreover, ET positively moderates the relationship between I-deals and UPB, the higher the ET, the stronger the relationship between I-deals and UPB. Conversely, the lower.
Journal Article
The Genome Architecture of the Collaborative Cross Mouse Genetic Reference Population
2012
The Collaborative Cross Consortium reports here on the development of a unique genetic resource population. The Collaborative Cross (CC) is a multiparental recombinant inbred panel derived from eight laboratory mouse inbred strains. Breeding of the CC lines was initiated at multiple international sites using mice from The Jackson Laboratory. Currently, this innovative project is breeding independent CC lines at the University of North Carolina (UNC), at Tel Aviv University (TAU), and at Geniad in Western Australia (GND). These institutions aim to make publicly available the completed CC lines and their genotypes and sequence information. We genotyped, and report here, results from 458 extant lines from UNC, TAU, and GND using a custom genotyping array with 7500 SNPs designed to be maximally informative in the CC and used a novel algorithm to infer inherited haplotypes directly from hybridization intensity patterns. We identified lines with breeding errors and cousin lines generated by splitting incipient lines into two or more cousin lines at early generations of inbreeding. We then characterized the genome architecture of 350 genetically independent CC lines. Results showed that founder haplotypes are inherited at the expected frequency, although we also consistently observed highly significant transmission ratio distortion at specific loci across all three populations. On chromosome 2, there is significant overrepresentation of WSB/EiJ alleles, and on chromosome X, there is a large deficit of CC lines with CAST/EiJ alleles. Linkage disequilibrium decays as expected and we saw no evidence of gametic disequilibrium in the CC population as a whole or in random subsets of the population. Gametic equilibrium in the CC population is in marked contrast to the gametic disequilibrium present in a large panel of classical inbred strains. Finally, we discuss access to the CC population and to the associated raw data describing the genetic structure of individual lines. Integration of rich phenotypic and genomic data over time and across a wide variety of fields will be vital to delivering on one of the key attributes of the CC, a common genetic reference platform for identifying causative variants and genetic networks determining traits in mammals.
Journal Article
Influence of Implicit Followership Cognitive Differences on Innovation Behavior: An Empirical Analysis in China
2020
The innovation behavior (IB) of followers is vital for individuals and organizations. It is not only an important part of individual performance but also an essential foundation of organizational innovation. In general, understanding the formation mechanism of followers’ IB could enhance organizational innovation performance and sustainable competitiveness. The innovation of this study includes the following points. First, in the previous research on the antecedent variables of the IB of followers, the key factor of implicit follow cognitive difference (IFCD) was not examined. We add this key factor to the independent variables of our formation mechanism. Second, in the relationship between IFCD and followers’ IB, we investigate the mediating role of psychological empowerment (PE) and the moderating role of person-organization Fit (P-O Fit), further shown as a mediation model with moderating variables. Third, this study adopts a longitudinal research design, and the data were obtained from 1:1 matched leaders and their followers of large and medium-sized enterprises in China. To avoid deviation in the homologous method, this study gathers data at three-month intervals to ensure that leadership’s influence on followers is effective. In this study, Amos 24.0 and SPSS 24.0 are used for empirical research. The results show IFCD has a negative effect on the IB of followers; PE has a partial mediating effect on the relationship between IFCD and IB of followers; P-O Fit plays a positive regulatory role in the relationship between IFCD and PE, and P-O Fit moderates the mediating effect of PE on the relationship between IFCD and IB. Based on our empirical research, we put forward some feasible suggestions for company managers to increase sustainability in market competition by promoting the formation of the IB of followers.
Journal Article
Next-Generation Sequencing of Crown and Rhizome Transcriptome from an Upland, Tetraploid Switchgrass
by
Tobias, Christian M.
,
Palmer, Nathan A.
,
Vogel, Kenneth P.
in
Analysis
,
Aquatic plants
,
Biodiesel fuels
2012
The crown and rhizome transcriptome of an upland tetraploid switchgrass cultivar cv Summer well adapted to the upper Midwest was investigated using the Roche 454-FLX pyrosequencing platform. Overall, approximately one million reads consisting of 216 million bases were assembled into 27,687 contigs and 43,094 singletons. Analyses of these sequences revealed minor contamination with non-plant sequences (< 0.5%), indicating that a majority were for transcripts coded by the switchgrass genome. Blast2Gos comparisons resulted in the annotation of ~65% of the contig sequences and ~40% of the singleton sequences. Contig sequences were mostly homologous to other plant sequences, dominated by matches to
Sorghum bicolor
genome. Singleton sequences, while displaying significant matches to
S. bicolor
, also contained sequences matching non-plant species. Comparisons of the 454 dataset to existing EST collections resulted in the identification of 30,177 new sequences. These new sequences coded for a number of different proteins and a selective analysis of two categories, namely, peroxidases and transcription factors, resulted in the identification of specific peroxidases and a number of low-abundance transcription factors expected to be involved in chromatin remodeling. KEGG maps for glycolysis and sugar metabolism showed high levels of transcript coding for enzymes involved in primary metabolism. The assembly provided significant insights into the status of these tissues and broadly indicated that there was active metabolism taking place in the crown and rhizomes at post-anthesis, the seed maturation stage of plant development.
Journal Article