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Genetic Regulation (genetic + regulation)
Selected AbstractsGenetic Regulation of Bone Traits Is Influenced by Sex and Reciprocal Cross in F2 Progeny From GK and F344 Rats,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 6 2009Sofia Lagerholm Abstract A genome-wide linkage analysis to identify quantitative trait loci (QTLs) for bone phenotypes was performed in an F2 intercross of inbred spontaneously type 2 diabetic GK and normoglycemic F344 rats (108 males and 98 females). The aim of the study was to locate genome regions with candidate genes affecting trabecular and cortical bone and to investigate the effects of sex and reciprocal cross. pQCT was used to determine tibial bone phenotypes in the F2 rats, comprising reciprocal crosses with divergent mitochondrial (mt) DNA. Sex and reciprocal cross-separated QTL analyses were performed followed by assessment of specific interactions. Four genome-wide significant QTLs linked to either cortical vBMD, tibia length, body length, or metaphyseal area were identified in males on chromosomes (chr) 1, 8, and 15. In females, three significant QTLs linked to cortical BMC or metaphyseal total vBMD were identified on chr 1 and 2. Several additional suggestive loci for trabecular and cortical traits were detected in both males and females. Four female-specific QTLs on chr 2, 3, 5, and 10 and four reciprocal cross-specific QTLs on chr 1, 10, and 18 were identified, suggesting that both sex and mt genotype influence the expression of bone phenotypes. [source] Mechanisms of Regulation of Litter Size in Pigs on the Genome LevelREPRODUCTION IN DOMESTIC ANIMALS, Issue 2007O Distl Contents Improvement in litter size has become of great interest in pig industry as good fecundity is directly related to a sow's productive life. Genetic regulation of litter size is complex and the main component traits so far defined are ovulation rate, embryonic survival, uterus capacity, foetal survival and pre-weaning losses. Improvements using concepts of the quantitative genetics let expect only slow genetic progress due to its low heritability of approximately 0.09 for number of piglets born alive. Marker assisted selection allows to dissect litter size in its component traits and using molecular genetic markers for the components of litter size traits promises more progress and advantages in optimum balancing of the different physiological mechanisms influencing litter size. In this review, efforts being made to unravel the genetic determinants of litter size are accounted and discussed. For litter size traits, more than 50 quantitative trait loci (QTL) were mapped and in more than 12 candidate genes associations confirmed. The number of useful candidate genes is much larger as shown by expression profiles and in addition, much more QTL can be assumed. These functional genomic approaches, both QTL mapping and candidate gene analysis, have to be merged for a better understanding of a wider application across different pig breeds and lines. Newly developed tools based on microarray techniques comprising DNA variants or expressed tags of many genes or even the whole genome appear useful for in depth understanding of the genetics of litter size in pigs. [source] A parallel and distributed-processing model of joint attention, social cognition and autismAUTISM RESEARCH, Issue 1 2009Peter Mundy Abstract The impaired development of joint attention is a cardinal feature of autism. Therefore, understanding the nature of joint attention is central to research on this disorder. Joint attention may be best defined in terms of an information-processing system that begins to develop by 4,6 months of age. This system integrates the parallel processing of internal information about one's own visual attention with external information about the visual attention of other people. This type of joint encoding of information about self and other attention requires the activation of a distributed anterior and posterior cortical attention network. Genetic regulation, in conjunction with self-organizing behavioral activity, guides the development of functional connectivity in this network. With practice in infancy the joint processing of self,other attention becomes automatically engaged as an executive function. It can be argued that this executive joint attention is fundamental to human learning as well as the development of symbolic thought, social cognition and social competence throughout the life span. One advantage of this parallel and distributed-processing model of joint attention is that it directly connects theory on social pathology to a range of phenomena in autism associated with neural connectivity, constructivist and connectionist models of cognitive development, early intervention, activity-dependent gene expression and atypical ocular motor control. [source] Genetic regulation of stem cell origins in the mouse embryoCLINICAL GENETICS, Issue 2 2005A Ralston ,Stem cell' has practically become a household term, but what is a stem cell and where does it come from? Insight into these questions has come from the early mouse embryo, or blastocyst, from which three kinds of stem cells have been derived: embryonic stem (ES) cells, trophoblast stem (TS) cells, and extraembryonic endoderm (XEN) cells. These stem cells appear to derive from three distinct tissue lineages within the blastocyst: the epiblast, the trophectoderm, and the extraembryonic endoderm. Understanding how these lineages arise during development will illuminate efforts to understand the establishment and maintenance of the stem cell state and the mechanisms that restrict stem cell potency. Genetic analysis has enabled the identification of several genes important for lineage decisions in the mouse blastocyst. Among these, Oct4, Nanog, Cdx2, and Gata6 encode transcription factors required for the three lineages of the blastocyst and for the maintenance their respective stem cell types. Interestingly, genetic manipulation of several of these factors can cause lineage switching among these stem cells, suggesting that knowledge of key lineage-determining genes could help control differentiation of stem cells more generally. Pluripotent stem cells have also been isolated from the human blastocyst, but the relationship between these cells and stem cells of the mouse blastocyst remains to be explored. This review describes the genetic regulation of lineage allocation during blastocyst formation and discusses similarities and differences between mouse and human ES cells. [source] Microbial biodegradation of polyaromatic hydrocarbonsFEMS MICROBIOLOGY REVIEWS, Issue 6 2008Ri-He Peng Abstract Polycyclic aromatic hydrocarbons (PAHs) are widespread in various ecosystems and are pollutants of great concern due to their potential toxicity, mutagenicity and carcinogenicity. Because of their hydrophobic nature, most PAHs bind to particulates in soil and sediments, rendering them less available for biological uptake. Microbial degradation represents the major mechanism responsible for the ecological recovery of PAH-contaminated sites. The goal of this review is to provide an outline of the current knowledge of microbial PAH catabolism. In the past decade, the genetic regulation of the pathway involved in naphthalene degradation by different gram-negative and gram-positive bacteria was studied in great detail. Based on both genomic and proteomic data, a deeper understanding of some high-molecular-weight PAH degradation pathways in bacteria was provided. The ability of nonligninolytic and ligninolytic fungi to transform or metabolize PAH pollutants has received considerable attention, and the biochemical principles underlying the degradation of PAHs were examined. In addition, this review summarizes the information known about the biochemical processes that determine the fate of the individual components of PAH mixtures in polluted ecosystems. A deeper understanding of the microorganism-mediated mechanisms of catalysis of PAHs will facilitate the development of new methods to enhance the bioremediation of PAH-contaminated sites. [source] Sulfur assimilation and glutathione metabolism under cadmium stress in yeast, protists and plantsFEMS MICROBIOLOGY REVIEWS, Issue 4 2005David Mendoza-Cózatl Abstract Glutathione (,-glu-cys-gly; GSH) is usually present at high concentrations in most living cells, being the major reservoir of non-protein reduced sulfur. Because of its unique redox and nucleophilic properties, GSH serves in bio-reductive reactions as an important line of defense against reactive oxygen species, xenobiotics and heavy metals. GSH is synthesized from its constituent amino acids by two ATP-dependent reactions catalyzed by ,-glutamylcysteine synthetase and glutathione synthetase. In yeast, these enzymes are found in the cytosol, whereas in plants they are located in the cytosol and chloroplast. In protists, their location is not well established. In turn, the sulfur assimilation pathway, which leads to cysteine biosynthesis, involves high and low affinity sulfate transporters, and the enzymes ATP sulfurylase, APS kinase, PAPS reductase or APS reductase, sulfite reductase, serine acetyl transferase, O -acetylserine/O -acetylhomoserine sulfhydrylase and, in some organisms, also cystathionine ,-synthase and cystathionine ,-lyase. The biochemical and genetic regulation of these pathways is affected by oxidative stress, sulfur deficiency and heavy metal exposure. Cells cope with heavy metal stress using different mechanisms, such as complexation and compartmentation. One of these mechanisms in some yeast, plants and protists is the enhanced synthesis of the heavy metal-chelating molecules GSH and phytochelatins, which are formed from GSH by phytochelatin synthase (PCS) in a heavy metal-dependent reaction; Cd2+ is the most potent activator of PCS. In this work, we review the biochemical and genetic mechanisms involved in the regulation of sulfate assimilation-reduction and GSH metabolism when yeast, plants and protists are challenged by Cd2+. [source] Thermodynamic and kinetic analyses for understanding sequence-specific DNA recognitionGENES TO CELLS, Issue 5 2000Masayuki Oda Thermodynamic and kinetic analyses of biomolecular interactions reveal details of the energetic and dynamic features of molecular recognition processes, and complement structural analyses of the free and complexed conformations. The recent improvements in both isothermal titration calorimetry and surface plasmon resonance sensoring provide powerful tools for analysing biomolecular interactions in thermodynamic and kinetic approaches. The thermodynamic and kinetic parameters obtained for binding between protein and DNA indicate the mechanism of specific DNA recognition, in the high-resolution structures of the protein,DNA complexes. The effects of temperature and ionic strength reflect the conformational changes of the protein and DNA molecules upon complex formation, including important contributions of water and solutes. When combined with mutational studies, the interactions can be reduced to several energetic contributions from individual contacts. These studies should be useful to determine general features of protein functions in genetic regulation. [source] Ovariectomy-Induced Bone Loss Varies Among Inbred Strains of Mice,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 7 2005Mary L Bouxsein PhD Abstract There is a subset of women who experience particularly rapid bone loss during and after the menopause. However, the factors that lead to this enhanced bone loss remain obscure. We show that patterns of bone loss after ovariectomy vary among inbred strains of mice, providing evidence that there may be genetic regulation of bone loss induced by estrogen deficiency. Introduction: Both low BMD and increased rate of bone loss are risk factors for fracture. Bone loss during and after the menopause is influenced by multiple hormonal factors. However, specific determinants of the rate of bone loss are poorly understood, although it has been suggested that genetic factors may play a role. We tested whether genetic factors may modulate bone loss subsequent to estrogen deficiency by comparing the skeletal response to ovariectomy in inbred strains of mice. Materials and Methods: Four-month-old mice from five inbred mouse strains (C3H/HeJ, BALB/cByJ, CAST/EiJ, DBA2/J, and C57BL/6J) underwent ovariectomy (OVX) or sham-OVX surgery (n = 6-9/group). After 1 month, mice were killed, and ,CT was used to compare cortical and trabecular bone response to OVX. Results: The effect of OVX on trabecular bone varied with mouse strain and skeletal site. Vertebral trabecular bone volume (BV/TV) declined after OVX in all strains (,15 to ,24%), except for C3H/HeJ. In contrast, at the proximal tibia, C3H/HeJ mice had a greater decline in trabecular BV/TV (,39%) than C57BL/6J (,18%), DBA2/J (,23%), and CAST/EiJ mice (,21%). OVX induced declines in cortical bone properties, but in contrast to trabecular bone, the effect of OVX did not vary by mouse strain. The extent of trabecular bone loss was greatest in those mice with highest trabecular BV/TV at baseline, whereas cortical bone loss was lowest among those with high cortical bone parameters at baseline. Conclusions: We found that the skeletal response to OVX varies in a site- and compartment-specific fashion among inbred mouse strains, providing support for the hypothesis that bone loss during and after the menopause is partly genetically regulated. [source] Mapping Quantitative Trait Loci for Vertebral Trabecular Bone Volume Fraction and Microarchitecture in Mice,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 4 2004Mary L Bouxsein Abstract BMD, which reflects both cortical and cancellous bone, has been shown to be highly heritable; however, little is known about the specific genetic factors regulating trabecular bone. Genome-wide linkage analysis of vertebral trabecular bone traits in 914 adult female mice from the F2 intercross of C57BL/6J and C3H/HeJ inbred strains revealed a pattern of genetic regulation derived from 13 autosomes, with 5,13 QTLs associated with each of the traits. Ultimately, identification of genes that regulate trabecular bone traits may yield important information regarding mechanisms that regulate mechanical integrity of the skeleton. Introduction: Both cortical and cancellous bone influence the mechanical integrity of the skeleton, with the relative contribution of each varying with skeletal site. Whereas areal BMD, which reflects both cortical and cancellous bone, has been shown to be highly heritable, little is known about the genetic determinants of trabecular bone density and architecture. Materials and Methods: To identify heritable determinants of vertebral trabecular bone traits, we evaluated the fifth lumbar vertebra from 914 adult female mice from the F2 intercross of C57BL/6J (B6) and C3H/HeJ (C3H) progenitor strains. High-resolution ,CT was used to assess total volume (TV), bone volume (BV), bone volume fraction (BV/TV), trabecular thickness (Tb.Th), separation (Tb.Sp), and number (Tb.N) of the trabecular bone in the vertebral body in the progenitors (n = 8/strain) and female B6C3H-F2 progeny (n = 914). Genomic DNA from F2 progeny was screened for 118 PCR-based markers discriminating B6 and C3H alleles on all 19 autosomes. Results and Conclusions: Despite having a slightly larger trabecular bone compartment, C3H progenitors had dramatically lower vertebral trabecular BV/TV (,53%) and Tb.N (,40%) and higher Tb.Sp (71%) compared with B6 progenitors (p < 0.001 for all). Genome-wide quantitative trait analysis revealed a pattern of genetic regulation derived from 13 autosomes, with 5,13 quantitative trait loci (QTLs) associated with each of the vertebral trabecular bone traits, exhibiting adjusted LOD scores ranging from 3.1 to 14.4. The variance explained in the F2 population by each of the individual QTL after adjusting for contributions from other QTLs ranged from 0.8% to 5.9%. Taken together, the QTLs explained 22,33% of the variance of the vertebral traits in the F2 population. In conclusion, we observed a complex pattern of genetic regulation for vertebral trabecular bone volume fraction and microarchitecture using the F2 intercross of the C57BL/6J and C3H/HeJ inbred mouse strains and identified a number of QTLs, some of which are distinct from those that were previously identified for total femoral and vertebral BMD. Identification of genes that regulate trabecular bone traits may ultimately yield important information regarding the mechanisms that regulate the acquisition and maintenance of mechanical integrity of the skeleton. [source] Genetic loci influencing natural variations in femoral bone morphometry in mice,JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2001Thomas A. Drake This study identifies genetic loci affecting femoral bone length and width measures in mature mice. Sixteen month old female F2 progeny of a C57BL/6J and DBA/2J intercross were examined for femur length and width of the femoral head, intertrochanteric region and three locations of the diaphysis using digitized images of femur radiographs obtained in the anterior-posterior and lateral projections. A genome wide linkage map was constructed using microsatellite markers at an average density of 20 cM, and quantitative trait locus analysis used to identify regions of the genome showing linkage with the traits measured. Femur length showed significant linkage with loci on proximal chromosome 3 (lod 6.1), and suggestive linkage with a locus on chromosome 14. A major locus on mid-chromosome 7 controlled width of the diaphysis (lod 6.8). Other loci were identified on chromosomes 2 and 4. Width at the intertrochanteric region had suggestive linkage with loci on chromosomes 6 and 19. No loci were found with linkage for width of the femoral head. Candidate genes related to bone development or metabolism are present at most of these loci. These findings show that genetic regulation of femoral bone morphology is complex, and are consistent with the distinct biologic processes that control longitudinal and lateral growth of the femur. © 2001 Orthopaedic Research Society. Punlished by Elsevier Science Ltd. All rights reserved. [source] Apoptosis in amyotrophic lateral sclerosis: a review of the evidenceNEUROPATHOLOGY & APPLIED NEUROBIOLOGY, Issue 4 2001S. Sathasivam Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease primarily affecting the upper and lower motor neurones of the central nervous system. Recently, a lot of interest has been generated by the possibility that a mechanism of programmed cell death, termed apoptosis, is responsible for the motor neurone degeneration in this condition. Apoptosis is regulated through a variety of different pathways which interact and eventually lead to controlled cell death. Apart from genetic regulation, factors involved in the control of apoptosis include death receptors, caspases, Bcl-2 family of oncoproteins, inhibitor of apoptosis proteins (IAPs), inhibitors of IAPs, the p53 tumour suppressor protein and apoptosis-related molecules. The first part of this article will give an overview of the current knowledge of apoptosis. In the second part of this review, we will examine in detail the evidence for and against the contribution of apoptosis in motor neurone cell death in ALS, looking at cellular-, animal- and human post-mortem tissue-based models. In a chronic neurodegenerative disease such as ALS, conclusive evidence of apoptosis is likely to be difficult to detect, given the rapidity of the apoptotic cell death process in relation to the relatively slow time course of the disease. Although a complete picture of motor neurone death in ALS has not been fully elucidated, there is good and compelling evidence that a programmed cell death pathway operates in this disorder. The strongest body of evidence supporting this comes from the findings that, in ALS, changes in the levels of members of the Bcl-2 family of oncoproteins results in a predisposition towards apoptosis, there is increased expression or activation of caspases-1 and -3, and the dying motor neurones in human cases exhibit morphological features reminiscent of apoptosis. Further supporting evidence comes from the detection of apoptosis-related molecules and anti-Fas receptor antibodies in human cases of ALS. However, the role of the p53 protein in cell death in ALS is at present unclear. An understanding of the mechanism of programmed cell death in ALS may provide important clues for areas of potential therapeutic intervention for neuroprotection in this devastating condition. [source] Phytochromes differentially regulate seed germination responses to light quality and temperature cues during seed maturationPLANT CELL & ENVIRONMENT, Issue 10 2009JENNIFER M. DECHAINE ABSTRACT The ratio of red to far-red light (R : FR) experienced by seeds during maturation affects germination, but the genetic regulation of this effect is poorly understood. In Arabidopsis thaliana, responses to R : FR are governed by five phytochrome photoreceptors, PHYA,PHYE. PHYA, PHYB and PHYE mediate germination, but their roles in germination response to the seed maturation environment are largely unknown. Seeds of A. thaliana phytochrome mutants and natural accessions were matured in a factorial combination of cold (16 °C) and warm (24 °C) temperatures and high (R : FR = 1) and low (R : FR = 0.6) R : FR environments, resembling sunlight and foliar shade, respectively. Germination was observed in resulting seeds. All five phytochromes mediated germination responses to seed maturation temperature and/or R : FR environment. PHYA suppressed germination in seeds matured under cold temperature, and PHYB promoted germination under the same conditions. PHYD and PHYE promoted germination of seeds matured under warm temperature, but this effect diminished when seeds matured under reduced R : FR. The A. thaliana natural accessions exhibited interesting variation in germination responses to the experimental conditions. Our results suggest that the role of individual PHY loci in regulating plant responses to R : FR varies depending on temperature and provide novel insights into the genetic basis of maternal effects. [source] ANAC012, a member of the plant-specific NAC transcription factor family, negatively regulates xylary fiber development in Arabidopsis thalianaTHE PLANT JOURNAL, Issue 6 2007Jae-Heung Ko Summary Vascular plants evolved to have xylem that provides physical support for their growing body and serves as a conduit for water and nutrient transport. In a previous study, we used comparative-transcriptome analyses to select a group of genes that were upregulated in xylem of Arabidopsis plants undergoing secondary growth. Subsequent analyses identified a plant-specific NAC-domain transcription factor gene (ANAC012) as a candidate for genetic regulation of xylem formation. Promoter-GUS analyses showed that ANAC012 expression was preferentially localized in the (pro)cambium region of inflorescence stem and root. Using yeast transactivation analyses, we confirmed the function of ANAC012 as a transcriptional activator, and identified an activation domain in the C terminus. Ectopic overexpression of ANAC012 in Arabidopsis (35S::ANAC012 plants) dramatically suppressed secondary wall deposition in the xylary fiber and slightly increased cell-wall thickness in the xylem vessels. Cellulose compositions of the cell wall were decreased in the inflorescent stems and roots of 35S::ANAC012 plants, probably resulting from defects in xylary fiber formation. Our data suggest that ANAC012 may act as a negative regulator of secondary wall thickening in xylary fibers. [source] Association of Genetic Variants, Ethnicity and Preterm Birth with Amniotic Fluid Cytokine ConcentrationsANNALS OF HUMAN GENETICS, Issue 2 2010Ramkumar Menon SUMMARY We examined the association of 166 single nucleotide polymorphisms (SNPs) in cytokines and cytokine related genes with cytokine concentrations (IL-1,, IL-8, and IL-10) in the amniotic fluid (AF). These cytokines have been associated with spontaneous preterm birth (PTB) and their genetic regulation may play a role in disease risk. These associations were studied in both PTB and term births in African Americans and Caucasians; maternal and fetal genotypes were studied separately. Analyses modeled genotype, pregnancy status, and marker by pregnancy status (case/control) interaction with cytokine concentration as outcome. Our results indicate that AF cytokines (IL-1, and IL-10) were associated with interactions between pregnancy status and both maternal and fetal SNPs, with the most significant interactions being observed for African Americans with IL-1, concentration (maternal at IL1RAP rs1024941 p < 10,3, fetal IL1RAP rs3773953 p < 10,3). AF IL-10 concentrations also showed evidence for association with SNPs in both ethnicities with the most significant interaction in Caucasian maternal samples (IL10 rs1800896 p < 10,3). Our data indicate that the genetic regulation of cytokine concentrations in PTB likely differs by ethnicity. AF cytokine concentrations were associated with interactions between genotype and PTB in African Americans, but less so in Caucasians. [source] Osteoprotegerin Plasma Levels are Strongly Associated with Polymorphisms in Human Homologue of the Mouse Progressive Ankylosis (ANKH) GeneANNALS OF HUMAN GENETICS, Issue 3 2007Y. Vistoropsky Summary Osteoprotegerin inhibits osteoclastogenesis and plays an important role in the control of bone resorption. However, the genetic mechanisms underlying regulation of OPG levels are currently not fully elucidated. The aim of the present study was to determine whether the ANKH gene, which plays a central role in bone mineralization, contributes to the genetic regulation of OPG levels. A family-based association study used a sample of 159 ethnically homogeneous nuclear families, comprising 556 apparently healthy individuals. Statistical analyses included family aggregation analysis of OPG variation and four types of transmission disequilibrium tests. Each individual was genotyped for 11 SNPs in the ANKH gene. Four TDTs consistently showed a highly significant association between OPG levels and the intronic SNP rs875525 located between exons 6 and 7. The combined p-value for four tests to reject the null hypothesis of no association was 0.0003. Furthermore, haplotypes generated between rs875525 and two additional neighbouring SNPs (rs2291943 and rs2288474) also revealed a significant association with OPG plasma levels (p < 10,4 -10,3). ANKH genetic polymorphisms in the area between SNP rs2291943 and rs2288474 are strongly associated with OPG plasma levels. The molecular mechanism underlying this association is not obvious, and therefore these results should be regarded cautiously until they are confirmed in independent studies. [source] A comparative genetic analysis between collagen-induced arthritis and pristane-induced arthritisARTHRITIS & RHEUMATISM, Issue 8 2003Peter Olofsson Objective To compare the genetic regulation of collagen-induced arthritis (CIA) with that of pristane-induced arthritis (PIA) in rats. Methods A genome-wide linkage analysis of an (E3 × DA)DA backcross of rats with CIA (n = 364 male rats; the same strain combinations as previously used to determine the genetic control of PIA) was performed. The strongest loci in both CIA and PIA (i.e., Cia12/Pia4 and Cia13/Pia7) were isolated in congenic strains. Susceptibility in both congenic strains was tested in rats with CIA and in rats with PIA. Results We found a striking, although not complete, similarity of the arthritis-controlling loci in CIA and in PIA, as well as the previously defined loci associated with cartilage destruction, antibody production, and the acute-phase response. All major PIA quantitative trait loci (QTLs) identified in early severe arthritis were also strong regulators of CIA. The 2 strongest QTLs, Cia12/Pia4 on chromosome 12 and Cia13/Pia7 on chromosome 4, were also analyzed in congenic strains with DA or E3 as the background genome. Consistent with the results of linkage analysis, the congenic strain experiments showed that the chromosome 4 locus was more penetrant in CIA than in PIA, while the chromosome 12 locus almost completely dominated the control of PIA severity. Conclusion The underlying genetic control of CIA was found to have many, but not all, pathogenic mechanisms in common with PIA, despite the use of a cartilage-specific antigen (type II collagen) to induce CIA but not PIA. [source] Comparison of enzymes involved in sugar metabolism from Shang-24 (Vinifera quinguangularis) and Cabernet Sauvignon (Vinifera vinifera) at veraisonAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 1 2009Q.-H. PAN Abstract Background and Aims:, Sugar is a main contributor to the quality of grape berries, but little is known about the characteristics of sugar metabolism in Chinese wild grapes. Here, enzymes related to sugar metabolism were investigated in berries of both Shang-24 (Vitis quinguangularis Rehd), a wild grape native to China, and Cabernet Sauvignon (V. vinifera L.). Methods and Results:, Analyses using high performance liquid chromatography and spectrophotometer showed that Shang-24 contained lower levels of glucose and fructose, compared with Cabernet Sauvignon, but had higher activities of enzymes related to sugar hydrolysis, particularly soluble acid invertase (SAI) and ,-amylase. Analyses of enzyme kinetics, enzyme-linked immunosorbent assay and Western blot revealed that SAI and ,-amylase in Shang-24 had low Km values and that high levels of both enzymes were present. Furthermore, a novel peptide of SAI of 105 kDa was detected in Shang-24 along with a peptide of 60 kDa that also was present in Cabernet Sauvignon. Conclusions:, It is thus suggested that biochemical characteristics of SAI and ,-amylase in Shang-24 differ from those in Cabernet Sauvignon, and the novel peptide may be related to high activity of SAI in Shang-24. Significance of the Study:, These data provide an essential basis for further study of the genetic regulation of sugar and its metabolism in grape berries. [source] Persea americana (avocado): bringing ancient flowers to fruit in the genomics eraBIOESSAYS, Issue 4 2008André S. Chanderbali The avocado (Persea americana) is a major crop commodity worldwide. Moreover, avocado, a paleopolyploid, is an evolutionary "outpost" among flowering plants, representing a basal lineage (the magnoliid clade) near the origin of the flowering plants themselves. Following centuries of selective breeding, avocado germplasm has been characterized at the level of microsatellite and RFLP markers. Nonetheless, little is known beyond these general diversity estimates, and much work remains to be done to develop avocado as a major subtropical-zone crop. Among the goals of avocado improvement are to develop varieties with fruit that will "store" better on the tree, show uniform ripening and have better post-harvest storage. Avocado transcriptome sequencing, genome mapping and partial genomic sequencing will represent a major step toward the goal of sequencing the entire avocado genome, which is expected to aid in improving avocado varieties and production, as well as understanding the evolution of flowers from non-flowering seed plants (gymnosperms). Additionally, continued evolutionary and other comparative studies of flower and fruit development in different avocado strains can be accomplished at the gene expression level, including in comparison with avocado relatives, and these should provide important insights into the genetic regulation of fruit development in basal angiosperms. BioEssays 30:386,396, 2008. © 2008 Wiley Periodicals, Inc. [source] Comparative insect developmental genetics: phenotypes without mutantsBIOESSAYS, Issue 5 2001Rob Denell The last decade has seen a dramatic increase in interest in the extent to which morphological evolution depends on changes in regulatory pathways. Insects provide a fertile ground for study because of their diversity and our high level of understanding of the genetic regulation of development in Drosophila melanogaster. However, comparable genetic approaches are presently possible in only a small number of non-Drosophilid insects. In a recent paper, Hughes and Kaufman(1) have used a new methodology, RNA interference, in the milkweed bug, Oncopeltus fasciatus, to phenocopy the effects of mutations in Hox genes. RNA interference involves the injection of double-stranded RNA of the same sequence as the relevant mRNA resulting in a depletion of that transcript.(2) Hughes and Kaufman focused on the gnathal segments, which elaborate specialized appendages important to feeding. Their results indicate that gnathal adaptations in this bug are correlated with changes in Hox gene functions and interactions. BioEssays 23:379,382, 2001. © 2001 John Wiley & Sons, Inc. [source] Genetic regulation of stem cell origins in the mouse embryoCLINICAL GENETICS, Issue 2 2005A Ralston ,Stem cell' has practically become a household term, but what is a stem cell and where does it come from? Insight into these questions has come from the early mouse embryo, or blastocyst, from which three kinds of stem cells have been derived: embryonic stem (ES) cells, trophoblast stem (TS) cells, and extraembryonic endoderm (XEN) cells. These stem cells appear to derive from three distinct tissue lineages within the blastocyst: the epiblast, the trophectoderm, and the extraembryonic endoderm. Understanding how these lineages arise during development will illuminate efforts to understand the establishment and maintenance of the stem cell state and the mechanisms that restrict stem cell potency. Genetic analysis has enabled the identification of several genes important for lineage decisions in the mouse blastocyst. Among these, Oct4, Nanog, Cdx2, and Gata6 encode transcription factors required for the three lineages of the blastocyst and for the maintenance their respective stem cell types. Interestingly, genetic manipulation of several of these factors can cause lineage switching among these stem cells, suggesting that knowledge of key lineage-determining genes could help control differentiation of stem cells more generally. Pluripotent stem cells have also been isolated from the human blastocyst, but the relationship between these cells and stem cells of the mouse blastocyst remains to be explored. This review describes the genetic regulation of lineage allocation during blastocyst formation and discusses similarities and differences between mouse and human ES cells. [source] Distal limb malformations: underlying mechanisms and clinical associationsCLINICAL GENETICS, Issue 3 2001S Sifakis Congenital malformations of the extremities are conspicuous and have been described through the ages. Over the past decade, a wealth of knowledge has been generated regarding the genetic regulation of limb development and the underlying molecular mechanisms. Recent studies have identified several of the signaling molecules, growth factors, and transcriptional regulators involved in the initiation and maintenance of the apical ectodermal ridge (AER) as well as the molecular markers defining the three axes of the developing limb. Studies of abnormal murine phenotypes have uncovered the role played by genes such as p63 and Dactylin in the maintenance of AER activity. These phenotypes resemble human malformations and in this review we describe the underlying mechanisms and clinical associations of split hand/foot malformation and ectrodactyly,ectodermal dysplasia,cleft lip/palate syndrome, which have both been associated with mutations in the p63 gene. [source] | |||||||||||||||||||||||||