PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-25 (46)
 

Clipboard (0)
None

Select a Filter Below

Year of Publication
more »
1.  Complete Genome Sequence of Bacillus cereus NC7401, Which Produces High Levels of the Emetic Toxin Cereulide 
Journal of Bacteriology  2012;194(17):4767-4768.
We report the complete and annotated genome sequence of Bacillus cereus NC7401, a representative of the strain group that causes emetic-type food poisoning. The emetic toxin, cereulide, is produced by a nonribosomal protein synthesis (NRPS) system that is encoded by a gene cluster on a large resident plasmid, pNCcld.
doi:10.1128/JB.01015-12
PMCID: PMC3415479  PMID: 22887669
2.  Draft Genome Sequence of Pediococcus lolii NGRI 0510QT Isolated from Ryegrass Silage 
Genome Announcements  2013;1(1):e00156-12.
Pediococcus lolii NGRI 0510QT was isolated from ryegrass silage produced on Ishigaki Island, Okinawa Prefecture, Japan. Here we present a draft genome sequence for this strain, consisting of 103 contigs for a total of 2,047,078 bp, 2,154 predicted coding sequences, and a G+C content of 42.1%.
doi:10.1128/genomeA.00156-12
PMCID: PMC3569353  PMID: 23405350
3.  Human Monoclonal Antibodies Broadly Neutralizing against Influenza B Virus 
PLoS Pathogens  2013;9(2):e1003150.
Influenza virus has the ability to evade host immune surveillance through rapid viral genetic drift and reassortment; therefore, it remains a continuous public health threat. The development of vaccines producing broadly reactive antibodies, as well as therapeutic strategies using human neutralizing monoclonal antibodies (HuMAbs) with global reactivity, has been gathering great interest recently. Here, three hybridoma clones producing HuMAbs against influenza B virus, designated 5A7, 3A2 and 10C4, were prepared using peripheral lymphocytes from vaccinated volunteers, and were investigated for broad cross-reactive neutralizing activity. Of these HuMAbs, 3A2 and 10C4, which recognize the readily mutable 190-helix region near the receptor binding site in the hemagglutinin (HA) protein, react only with the Yamagata lineage of influenza B virus. By contrast, HuMAb 5A7 broadly neutralizes influenza B strains that were isolated from 1985 to 2006, belonging to both Yamagata and Victoria lineages. Epitope mapping revealed that 5A7 recognizes 316G, 318C and 321W near the C terminal of HA1, a highly conserved region in influenza B virus. Indeed, no mutations in the amino acid residues of the epitope region were induced, even after the virus was passaged ten times in the presence of HuMAb 5A7. Moreover, 5A7 showed significant therapeutic efficacy in mice, even when it was administered 72 hours post-infection. These results indicate that 5A7 is a promising candidate for developing therapeutics, and provide insight for the development of a universal vaccine against influenza B virus.
Author Summary
Influenza virus is classified into types A, B and C. Influenza A virus is further divided into many subtypes, all of which exist in animals, indicating pandemic potential. By contrast, influenza B virus circulates almost exclusively in humans and, as there is no evidence for reassortment with influenza A virus, there is no indication of pandemic potential. Hence, there is far less accumulated research information regarding influenza B virus than influenza A virus. Influenza B virus, which is classified into two phylogenetic lineages, does, however, cause annual epidemics in humans and is therefore as essential to control as influenza A virus. Recently, the development of a universal vaccine and therapeutic strategies using human monoclonal antibodies (HuMAbs) has been gathering great interest. The present study reports a HuMAb neutralizing a wide range of influenza B viruses of both lineages. This HuMAb recognizes the conserved region of hemagglutinin. Moreover, therapeutic efficacy of this HuMAb was also confirmed by in vivo animal experiments. Thus, this study provides insight for the development of broad-spectrum therapeutics and a universal prophylactic vaccine against influenza B virus.
doi:10.1371/journal.ppat.1003150
PMCID: PMC3567173  PMID: 23408886
6.  Vasohibin-1 is identified as a master-regulator of endothelial cell apoptosis using gene network analysis 
BMC Genomics  2013;14:23.
Background
Apoptosis is a critical process in endothelial cell (EC) biology and pathology, which has been extensively studied at protein level. Numerous gene expression studies of EC apoptosis have also been performed, however few attempts have been made to use gene expression data to identify the molecular relationships and master regulators that underlie EC apoptosis. Therefore, we sought to understand these relationships by generating a Bayesian gene regulatory network (GRN) model.
Results
ECs were induced to undergo apoptosis using serum withdrawal and followed over a time course in triplicate, using microarrays. When generating the GRN, this EC time course data was supplemented by a library of microarray data from EC treated with siRNAs targeting over 350 signalling molecules.
The GRN model proposed Vasohibin-1 (VASH1) as one of the candidate master-regulators of EC apoptosis with numerous downstream mRNAs. To evaluate the role played by VASH1 in EC, we used siRNA to reduce the expression of VASH1. Of 10 mRNAs downstream of VASH1 in the GRN that were examined, 7 were significantly up- or down-regulated in the direction predicted by the GRN.Further supporting an important biological role of VASH1 in EC, targeted reduction of VASH1 mRNA abundance conferred resistance to serum withdrawal-induced EC death.
Conclusion
We have utilised Bayesian GRN modelling to identify a novel candidate master regulator of EC apoptosis. This study demonstrates how GRN technology can complement traditional methods to hypothesise the regulatory relationships that underlie important biological processes.
doi:10.1186/1471-2164-14-23
PMCID: PMC3570387  PMID: 23324451
Vasohibin; HUVEC; Bayesian; Gene regulatory network
7.  A Simple Sequence Repeat- and Single-Nucleotide Polymorphism-Based Genetic Linkage Map of the Brown Planthopper, Nilaparvata lugens 
In this study, we developed the first genetic linkage map for the major rice insect pest, the brown planthopper (BPH, Nilaparvata lugens). The linkage map was constructed by integrating linkage data from two backcross populations derived from three inbred BPH strains. The consensus map consists of 474 simple sequence repeats, 43 single-nucleotide polymorphisms, and 1 sequence-tagged site, for a total of 518 markers at 472 unique positions in 17 linkage groups. The linkage groups cover 1093.9 cM, with an average distance of 2.3 cM between loci. The average number of marker loci per linkage group was 27.8. The sex-linkage group was identified by exploiting X-linked and Y-specific markers. Our linkage map and the newly developed markers used to create it constitute an essential resource and a useful framework for future genetic analyses in BPH.
doi:10.1093/dnares/dss030
PMCID: PMC3576655  PMID: 23204257
Nilaparvata lugens; brown planthopper; genetic linkage map; SSR; SNP
8.  Genome Sequence of Pantoea agglomerans Strain IG1 
Journal of Bacteriology  2012;194(5):1258-1259.
Pantoea agglomerans is a Gram-negative bacterium that grows symbiotically with various plants. Here we report the 4.8-Mb genome sequence of P. agglomerans strain IG1. The lipopolysaccharides derived from P. agglomerans IG1 have been shown to be effective in the prevention of various diseases, such as bacterial or viral infection, lifestyle-related diseases. This genome sequence represents a substantial step toward the elucidation of pathways for production of lipopolysaccharides.
doi:10.1128/JB.06674-11
PMCID: PMC3294790  PMID: 22328756
9.  Urinary 2-hydroxy-5-oxoproline, the lactam form of α-ketoglutaramate, is markedly increased in urea cycle disorders 
Analytical and bioanalytical chemistry  2011;400(7):1843-1851.
α-Ketoglutaramate (KGM) is the α-keto acid analogue of glutamine, which exists mostly in equilibrium with a lactam form (2-hydroxy-5-oxoproline) under physiological conditions. KGM was identified in human urine and its concentration quantified by gas chromatography/mass spectrometry (GC/MS). The keto acid was shown to be markedly elevated in urine obtained from patients with primary hyperammonemia due to an inherited metabolic defect in any one of the five enzymes of the urea cycle. Increased urinary KGM was also noted in other patients with primary hyperammonemia, including three patients with a defect resulting in lysinuric protein intolerance and one of two patients with a defect in the ornithine transporter I. These findings indicate disturbances in nitrogen metabolism, most probably at the level of glutamine metabolism in primary hyperammonemia diseases. Urinary KGM levels, however, were not well correlated with secondary hyperammonemia in patients with propionic acidemia or methylmalonic acidemia, possibly as a result, in part, of decreased glutamine levels. In conclusion, the GC/MS procedure has the required lower limit of quantification for analysis of urinary KGM, which is markedly increased in urea cycle disorders and other primary hyperammonemic diseases.
doi:10.1007/s00216-011-4688-x
PMCID: PMC3412270  PMID: 21298421
α-Ketoglutaramate; 2-hydroxy-5-oxoproline; GC/MS analysis of urine; Primary hyperammonemia; Secondary hyperammonemia; Urea cycle disorders
10.  Synaptic Polarity Depends on Phosphatidylinositol Signaling Regulated by myo-Inositol Monophosphatase in Caenorhabditis elegans 
Genetics  2012;191(2):509-521.
Although neurons are highly polarized, how neuronal polarity is generated remains poorly understood. An evolutionarily conserved inositol-producing enzyme myo-inositol monophosphatase (IMPase) is essential for polarized localization of synaptic molecules in Caenorhabditis elegans and can be inhibited by lithium, a drug for bipolar disorder. The synaptic defect of IMPase mutants causes defects in sensory behaviors including thermotaxis. Here we show that the abnormalities of IMPase mutants can be suppressed by mutations in two enzymes, phospholipase Cβ or synaptojanin, which presumably reduce the level of membrane phosphatidylinositol 4,5-bisphosphate (PIP2). We also found that mutations in phospholipase Cβ conferred resistance to lithium treatment. Our results suggest that reduction of PIP2 on plasma membrane is a major cause of abnormal synaptic polarity in IMPase mutants and provide the first in vivo evidence that lithium impairs neuronal PIP2 synthesis through inhibition of IMPase. We propose that the PIP2 signaling regulated by IMPase plays a novel and fundamental role in the synaptic polarity.
doi:10.1534/genetics.111.137844
PMCID: PMC3374314  PMID: 22446320
bipolar disorder; Caenorhabditis elegans; myo-inositol monophosphatase (IMPase); synapse; lithium
11.  Genome Sequence of the White Koji Mold Aspergillus kawachii IFO 4308, Used for Brewing the Japanese Distilled Spirit Shochu 
Eukaryotic Cell  2011;10(11):1586-1587.
The filamentous fungus Aspergillus kawachii has traditionally been used for brewing the Japanese distilled spirit shochu. A. kawachii characteristically hyperproduces citric acid and a variety of polysaccharide glycoside hydrolases. Here the genome sequence of A. kawachii IFO 4308 was determined and annotated. Analysis of the sequence may provide insight into the properties of this fungus that make it superior for use in shochu production, leading to the further development of A. kawachii for industrial applications.
doi:10.1128/EC.05224-11
PMCID: PMC3209066  PMID: 22045919
12.  A Proposal of a Practical and Optimal Prophylactic Strategy for Peritoneal Recurrence 
Journal of Oncology  2012;2012:340380.
Peritoneal metastasis, which often arises in patients with advanced gastric cancer, is well known as a miserable and ill-fated disease. Once peritoneal metastasis is formed, it is extremely difficult to defeat. We advocated EIPL (extensive intraoperative peritoneal lavage) as a useful and practical adjuvant surgical technique for those gastric cancer patients who are likely to suffer from peritoneal recurrence. In this paper, we review the effect of EIPL therapy on prevention of peritoneal recurrence on patients with peritoneal free cancer cells without overt peritoneal metastasis (CY+/P−) through the prospective randomized study, and we verified its potential as an optimal and standard prophylactic therapeutic strategy for peritoneal recurrence.
doi:10.1155/2012/340380
PMCID: PMC3306955  PMID: 22481921
15.  Gene network inference and visualization tools for biologists: application to new human transcriptome datasets 
Nucleic Acids Research  2011;40(6):2377-2398.
Gene regulatory networks inferred from RNA abundance data have generated significant interest, but despite this, gene network approaches are used infrequently and often require input from bioinformaticians. We have assembled a suite of tools for analysing regulatory networks, and we illustrate their use with microarray datasets generated in human endothelial cells. We infer a range of regulatory networks, and based on this analysis discuss the strengths and limitations of network inference from RNA abundance data. We welcome contact from researchers interested in using our inference and visualization tools to answer biological questions.
doi:10.1093/nar/gkr902
PMCID: PMC3315333  PMID: 22121215
16.  Whole-Genome Sequencing of Sake Yeast Saccharomyces cerevisiae Kyokai no. 7 
The term ‘sake yeast’ is generally used to indicate the Saccharomyces cerevisiae strains that possess characteristics distinct from others including the laboratory strain S288C and are well suited for sake brewery. Here, we report the draft whole-genome shotgun sequence of a commonly used diploid sake yeast strain, Kyokai no. 7 (K7). The assembled sequence of K7 was nearly identical to that of the S288C, except for several subtelomeric polymorphisms and two large inversions in K7. A survey of heterozygous bases between the homologous chromosomes revealed the presence of mosaic-like uneven distribution of heterozygosity in K7. The distribution patterns appeared to have resulted from repeated losses of heterozygosity in the ancestral lineage of K7. Analysis of genes revealed the presence of both K7-acquired and K7-lost genes, in addition to numerous others with segmentations and terminal discrepancies in comparison with those of S288C. The distribution of Ty element also largely differed in the two strains. Interestingly, two regions in chromosomes I and VII of S288C have apparently been replaced by Ty elements in K7. Sequence comparisons suggest that these gene conversions were caused by cDNA-mediated recombination of Ty elements. The present study advances our understanding of the functional and evolutionary genomics of the sake yeast.
doi:10.1093/dnares/dsr029
PMCID: PMC3223075  PMID: 21900213
Saccharomyces cerevisiae; sake yeast; genome sequence; diploid; loss of heterozygosity
17.  Progression of viraemia during treatment with infliximab in a patient with rheumatoid arthritis and chronic hepatitis C infection 
BMJ Case Reports  2009;2009:bcr04.2009.1732.
Tumour necrosis factor α (TNFα) antagonists are effective for the treatment of rheumatoid arthritis (RA), but concerns remain about their safety in the presence of hepatitis C virus (HCV) infection. The influence of treatment with the TNFα antagonist infliximab on levels of HCV viraemia and serum transaminases in a 38-year-old patient with RA and HCV was examined to assess the safety of the drug. After starting infliximab treatment, the patient’s clinical symptoms improved significantly (28-joint Disease Activity Score (DAS28) of less than 3) and levels of transaminases were normal. At the 14th injection of infliximab, the levels of HCV viraemia and transaminases were significantly elevated. After stopping the infliximab injections, the levels of transaminases returned to normal with infusion of glycyrrhizinate derivatives within 3 months. Evidence is provided of aggravation of serum transaminases and progression of viraemia during treatment with infliximab in a patient with RA and HCV infection.
doi:10.1136/bcr.04.2009.1732
PMCID: PMC3027505  PMID: 21829428
18.  Generation of a monoclonal antibody reactive to prefusion myocytes 
We established a novel monoclonal antibody, Yaksa that is specific to a subpopulation of myogenic cells. The Yaksa antigen is not expressed on the surface of growing myoblasts but only on a subpopulation of myogenin-positive myocytes. When Yaksa antigen-positive mononucleated cells were freshly prepared from a murine myogenic cell by a cell sorter, they fused with each other and formed multinucleated myotubes shortly after replating while Yaksa antigen-negative cells scarcely generated myotubes. These results suggest that Yaksa could segregate fusion-competent, mononucleated cells from fusion–incompetent cells during muscle differentiation. The Yaksa antigen was also expressed in developing muscle and regenerating muscle in vivo and it was localized at sites of cell–cell contact between mono-nucleated muscle cells and between mono-nucleated muscle cells and myotubes. Thus, Yaksa that marks prefusion myocytes before myotube formation can be a useful tool to elucidate the cellular and molecular mechanisms of myogenic cell fusion.
Electronic supplementary material
The online version of this article (doi:10.1007/s10974-011-9247-8) contains supplementary material, which is available to authorized users.
doi:10.1007/s10974-011-9247-8
PMCID: PMC3141826  PMID: 21597958
Cell fusion; Myogenesis; Skeletal muscle; Prefusion
19.  hERGAPDbase: a database documenting hERG channel inhibitory potentials and APD-prolongation activities of chemical compounds 
Drug-induced QT interval prolongation is one of the most common reasons for the withdrawal of drugs from the market. In the past decade, at least nine drugs, i.e. terfenadine, astemizole, grepafloxacin, terodiline, droperidol, lidoflazine, sertindole, levomethadyl and cisapride, have been removed from the market or their use has been severely restricted because of drug-induced QT interval prolongation. Therefore, this irregularity is a major safety concern in the case of drugs submitted for regulatory approval. The most common mechanism of drug-induced QT interval prolongation may be drug-related inhibition of the human ether-á-go-go-related gene (hERG) channel, which subsequently results in prolongation of the cardiac action potential duration (APD). hERGAPDbase is a database of electrophysiological experimental data documenting potential hERG channel inhibitory actions and the APD-prolongation activities of chemical compounds. All data entries are manually collected from scientific papers and curated by a person. With hERGAPDbase, we aim to provide useful information for chemical and pharmacological scientists and enable easy access to electrophysiological experimental data on chemical compounds.
Database URL: http://www.grt.kyushu-u.ac.jp/hergapdbase/
doi:10.1093/database/bar017
PMCID: PMC3096323  PMID: 21586548
20.  Novel and Conserved Protein Macoilin Is Required for Diverse Neuronal Functions in Caenorhabditis elegans 
PLoS Genetics  2011;7(5):e1001384.
Neural signals are processed in nervous systems of animals responding to variable environmental stimuli. This study shows that a novel and highly conserved protein, macoilin (MACO-1), plays an essential role in diverse neural functions in Caenorhabditis elegans. maco-1 mutants showed abnormal behaviors, including defective locomotion, thermotaxis, and chemotaxis. Expression of human macoilin in the C. elegans nervous system weakly rescued the abnormal thermotactic phenotype of the maco-1 mutants, suggesting that macoilin is functionally conserved across species. Abnormal thermotaxis may have been caused by impaired locomotion of maco-1 mutants. However, calcium imaging of AFD thermosensory neurons and AIY postsynaptic interneurons of maco-1 mutants suggest that macoilin is required for appropriate responses of AFD and AIY neurons to thermal stimuli. Studies on localization of MACO-1 showed that C. elegans and human macoilins are localized mainly to the rough endoplasmic reticulum. Our results suggest that macoilin is required for various neural events, such as the regulation of neuronal activity.
Author Summary
Any animals, including humans, have to be capable of properly sensing and responding to various environmental stimuli for survival and reproduction. Environmental stimuli are evaluated and, based on past experiences, converted to produce appropriate adaptive behaviors. Even the small, free-living soil nematode Caenorhabditis elegans can sense diverse environment stimuli using a nervous system that consists of only 302 neurons. C. elegans exhibit thermotaxis that allows them to remember ambient temperatures and use this information as a cue to seek and remain near food sources. We show here that a novel and conserved protein, MACO-1, is important for proper execution of thermotaxis by C. elegans. The maco-1 gene was originally identified in a novel thermotaxis-defective mutant. Abnormal thermotaxis of maco-1 mutants was weakly but apparently rescued by expressing human MACO-1, suggesting that MACO-1 is functionally conserved among species. MACO-1 protein is required for appropriate regulation of neuronal activity, and the activity of neurons required for thermotaxis is impaired in maco-1 mutants. This analysis provides an important basis for the function of the macoilin family.
doi:10.1371/journal.pgen.1001384
PMCID: PMC3093358  PMID: 21589894
21.  Ameliorating effect of Yokukansan on the development of atopic dermatitis-like lesions and scratching behavior in socially isolated NC/Nga mice 
Archives of Dermatological Research  2011;303(9):659-667.
Yokukansan (YKS) has been used in Japan as a remedy for neurosis, insomnia, and children with night crying. In a previous study, we reported that YKS controls scratching behavior and inhibits the development of atopic dermatitis (AD)-like lesions in NC/Nga mice. In this study, we investigated the effects of YKS on the development of AD-like lesions in socially isolated NC/Nga mice compared with the effects of fexofenadine and elucidated the mechanism of the ameliorating effect of YKS on the skin lesions. Ten-week-old male NC/Nga mice were divided into three groups (n = 5/group): the conventional control, the YKS-treated, and the fexofenadine-treated groups, and were kept isolated under conventional conditions for 6 weeks. Measurements were made of dermatitis scores and transepidermal water loss (TEWL), scratching and grooming behaviors. Immunohistochemistry and mRNA levels were also evaluated. We performed similar experiments under specific pathogen free (SPF) conditions that served as a SPF control. YKS and fexofenadine inhibited the aggravation of skin lesions and decreased TEWL, but only YKS decreased the numbers of scratching and pathologic grooming behaviors. Immunohistochemistry and RT-PCR revealed that N-methyl-d-aspartate (NMDA) receptor expression was increased in the skin of conventional control mice and was decreased in YKS-treated mice. Glutamate transporter-1 (GLT-1) mRNA levels were decreased in the skin of conventional control mice and were increased in YKS-treated mice. The results indicate that YKS ameliorates AD-like skin lesions in NC/Nga mice through a mechanism distinct from that of fexofenadine. Furthermore, the effects of YKS are suggested to be mediated via glutamate signaling in the skin lesions.
doi:10.1007/s00403-011-1137-9
PMCID: PMC3197922  PMID: 21365206
Yokukansan; Atopic dermatitis; NC/Nga mice; Scratching behavior; NMDA receptor; GLT-1
22.  Bidirectional regulation of thermotaxis by glutamate transmissions in Caenorhabditis elegans 
The EMBO Journal  2011;30(7):1376-1388.
Bidirectional regulation of thermotaxis by glutamate transmissions in Caenorhabditis elegans
This paper provides a molecular and genetic analysis of the neural circuitry that regulates the migration of Caenorhabditis elegans towards either warmer or colder temperature and reveals an important role of glutamate signalling in this process.
In complex neural circuits of the brain, massive information is processed with neuronal communication through synaptic transmissions. It is thus fundamental to delineate information flows encoded by various kinds of transmissions. Here, we show that glutamate signals from two distinct sensory neurons bidirectionally affect the same postsynaptic interneuron, thereby producing the opposite behaviours. EAT-4/VGLUT (vesicular glutamate transporter)-dependent glutamate signals from AFD thermosensory neurons inhibit the postsynaptic AIY interneurons through activation of GLC-3/GluCl inhibitory glutamate receptor and behaviourally drive migration towards colder temperature. By contrast, EAT-4-dependent glutamate signals from AWC thermosensory neurons stimulate the AIY neurons to induce migration towards warmer temperature. Alteration of the strength of AFD and AWC signals led to significant changes of AIY activity, resulting in drastic modulation of behaviour. We thus provide an important insight on information processing, in which two glutamate transmissions encoding opposite information flows regulate neural activities to produce a large spectrum of behavioural outputs.
doi:10.1038/emboj.2011.13
PMCID: PMC3094115  PMID: 21304490
C. elegans; glutamate; neural circuit; neurotransmission; thermotaxis
23.  Identification of the Site-Specific DNA Invertase Responsible for the Phase Variation of SusC/SusD Family Outer Membrane Proteins in Bacteroides fragilis▿ † 
Journal of Bacteriology  2009;191(19):6003-6011.
The human gut microbe Bacteroides fragilis can alter the expression of its surface molecules, such as capsular polysaccharides and SusC/SusD family outer membrane proteins, through reversible DNA inversions. We demonstrate here that DNA inversions at 12 invertible regions, including three gene clusters for SusC/SusD family proteins, were controlled by a single tyrosine site-specific recombinase (Tsr0667) encoded by BF0667 in B. fragilis strain YCH46. Genetic disruption of BF0667 diminished or attenuated shufflon-type DNA inversions at all three susC/susD genes clusters, as well as simple DNA inversions at nine other loci, most of which colocalized with susC/susD family genes. The inverted repeat sequences found within the Tsr0667-regulated invertible regions shared the consensus motif sequence AGTYYYN4GDACT. Tsr0667 specifically mediated the DNA inversions of 10 of the 12 regions, even under an Escherichia coli background when the invertible regions were exposed to BF0667 in E. coli cells. Thus, Tsr0667 is an additional globally acting DNA invertase in B. fragilis, which probably involves the selective expression of SusC/SusD family outer membrane proteins.
doi:10.1128/JB.00687-09
PMCID: PMC2747901  PMID: 19648246
24.  Reduction of Ptf1a Gene Dosage Causes Pancreatic Hypoplasia and Diabetes in Mice 
Diabetes  2008;57(9):2421-2431.
OBJECTIVE—Most pancreatic endocrine cells derive from Ptf1a-expressing progenitor cells. In humans, nonsense mutations in Ptf1a have recently been identified as a cause of permanent neonatal diabetes associated with pancreatic agenesis. The death of Ptf1a-null mice soon after birth has not allowed further insight into the pathogenesis of the disease; it is therefore unclear how much pancreatic endocrine function is dependent on Ptf1a in mammals. This study aims to investigate gene-dosage effects of Ptf1a on pancreas development and function in mice.
RESEARCH DESIGN AND METHODS—Combining hypomorphic and null alleles of Ptf1a and Cre-mediated lineage tracing, we followed the cell fate of reduced Ptf1a-expressing progenitors and analyzed pancreas development and function in mice.
RESULTS—Reduced Ptf1a dosage resulted in pancreatic hypoplasia and glucose intolerance with insufficient insulin secretion in a dosage-dependent manner. In hypomorphic mutant mice, pancreatic bud size was small and substantial proportions of pancreatic progenitors were misspecified to the common bile duct and duodenal cells. Growth with branching morphogenesis and subsequent exocrine cytodifferentiation was reduced and delayed. Total β-cell number was decreased, proportion of non-β islet cells was increased, and α-cells were abnormally intermingled with β-cells. Interestingly, Pdx1 expression was decreased in early pancreatic progenitors but elevated to normal level at the mid-to-late stages of pancreatogenesis.
CONCLUSIONS—The dosage of Ptf1a is crucial for pancreas specification, growth, total β-cell number, islet morphogenesis, and endocrine function. Some neonatal diabetes may be caused by mutation or single nucleotide polymorphisms in the Ptf1a gene that reduce gene expression levels.
doi:10.2337/db07-1558
PMCID: PMC2518493  PMID: 18591390
25.  Whole-genome analyses reveal genetic instability of Acetobacter pasteurianus 
Nucleic Acids Research  2009;37(17):5768-5783.
Acetobacter species have been used for brewing traditional vinegar and are known to have genetic instability. To clarify the mutability, Acetobacter pasteurianus NBRC 3283, which forms a multi-phenotype cell complex, was subjected to genome DNA sequencing. The genome analysis revealed that there are more than 280 transposons and five genes with hyper-mutable tandem repeats as common features in the genome consisting of a 2.9-Mb chromosome and six plasmids. There were three single nucleotide mutations and five transposon insertions in 32 isolates from the cell complex. The A. pasteurianus hyper-mutability was applied for breeding a temperature-resistant strain grown at an unviable high-temperature (42°C). The genomic DNA sequence of a heritable mutant showing temperature resistance was analyzed by mutation mapping, illustrating that a 92-kb deletion and three single nucleotide mutations occurred in the genome during the adaptation. Alpha-proteobacteria including A. pasteurianus consists of many intracellular symbionts and parasites, and their genomes show increased evolution rates and intensive genome reduction. However, A. pasteurianus is assumed to be a free-living bacterium, it may have the potentiality to evolve to fit in natural niches of seasonal fruits and flowers with other organisms, such as yeasts and lactic acid bacteria.
doi:10.1093/nar/gkp612
PMCID: PMC2761278  PMID: 19638423

Results 1-25 (46)