			Home About us Contact

Severe Growth Retardation (severe + growth_retardation)

Distribution by Scientific Domains

Life Sciences	83%

Selected Abstracts

A member of the YER057c/yjgf/Uk114 family links isoleucine biosynthesis and intact mitochondria maintenance in Saccharomyces cerevisiae

GENES TO CELLS, Issue 6 2001
Jong-Myong Kim
Background Two paralogs, YIL051c and YER057c, in the Saccharomyces cerevisiae genome are members of the YER057c/Yigf/Uk114 family, which is highly conserved among Eubacteria, Archaea and Eukarya. Although the molecular function of this protein family is not clear, previous studies suggest that it plays a role in the regulation of metabolic pathways and cell differentiation. Results Yil051cp is 70% identical in amino acid sequence to Yer057cp, and differs in that the former is longer by 16 amino acids containing, in part, the mitochondrial targeting signal at the N-terminus of the protein. An HA-tagged protein of Yil051cp is localized strictly in mitochondria, while that of Yer057cp is found in both cytoplasm and nucleus. Disruption of YIL051c (yil051c,) resulted in severe growth retardation in glucose medium due to isoleucine auxotroph, and no growth in glycerol medium due to the loss of mitochondria. An extract prepared from yil051c, cells showed no transaminase activity for isoleucine, while that for valine or leucine was intact. Haploid yil051c, cells newly isolated from the YIL051c/yil051c, hetero-diploids gradually lost mitochondrial DNA within 24 h in the absence of, but not in the presence of, an isoleucine. Mutants either requiring leucine (leu2,112) or isoleucine-valine (bat1,, bat2,) in a YIL051c background showed no changes in mitochondrial DNA maintenance in the absence of requirements. Conclusions Based on these results, we named Yil051c as Ibm1 (Isoleucine Biosynthesis and Mitochondria maintenance1) and concluded that: (i) Ibm1p determines the specificity of isoleucine biosynthesis, probably at the transamination step, (ii) Ibm1p is required for the maintenance of mitochondrial DNA when isoleucine is deficient, and (iii) Isoleucine compensates for the lack of Ibm1p. Taken together, Ibm1p may act as a sensor for isoleucine deficiency as well as a regulator determining the specificity for branched amino acid transaminase. [source]

Expression of FGFR3 with the G380R Achondroplasia Mutation Inhibits Proliferation and Maturation of CFK2 Chondrocytic Cells

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2000
Janet E. Henderson
Abstract A G380R substitution in the transmembrane-spanning region of FGFR3 (FGFR3Ach) results in constitutive receptor kinase activity and is the most common cause of achondroplastic dwarfism in humans. The epiphyseal growth plates of affected individuals are disorganized and hypocellular and show aberrant chondrocyte maturation. To examine the molecular basis of these abnormalities, we used a chondrocytic cell line, CFK2, to stably express the b variant of wild-type FGFR3 or the the constitutively active FGFR3Ach. Overexpression of FGFR3 had minimal effects on CFK2 proliferation and maturation compared with the severe growth retardation found in cells expressing FGFR3Ach. Cells expressing the mutant receptor also showed an abnormal apoptotic response to serum deprivation and failed to undergo differentiation under appropriate culture conditions. These changes were associated with altered expression of integrin subunits, which effectively led to a switch in substrate preference of the immature cell from fibronectin to type II collagen. These in vitro observations support those from in vivo studies indicating that FGFR3 mediates an inhibitory influence on chondrocyte proliferation. We now suggest that the mechanism is related to altered integrin expression. [source]

Loss of cytosolic fructose-1,6-bisphosphatase limits photosynthetic sucrose synthesis and causes severe growth retardations in rice (Oryza sativa)

PLANT CELL & ENVIRONMENT, Issue 12 2008
SANG-KYU LEE
ABSTRACT During photosynthesis, triose-phosphates (trioseP) exported from the chloroplast to the cytosol are converted to sucrose via cytosolic fructose-1,6-bisphosphatase (cFBPase). Expression analysis in rice suggests that OscFBP1 plays a major role in the cytosolic conversion of trioseP to sucrose in leaves during the day. The isolated OscFBP1 mutants exhibited markedly decreased photosynthetic rates and severe growth retardation with reduced chlorophyll content, which results in plant death. Analysis of primary carbon metabolites revealed both significantly reduced levels of sucrose, glucose, fructose and starch in leaves of these mutants, and a high accumulation of sucrose to starch in leaves of rice plants. In the oscfbp1 mutants, products of glycolysis and the TCA cycle were significantly increased. A partitioning experiment of 14C-labelled photoassimilates revealed altered carbon distributions including a slight increase in the insoluble fraction representing transitory starch, a significant decrease in the neutral fraction corresponding to soluble sugars and a high accumulation of phosphorylated intermediates and carboxylic acid fractions in the oscfbp1 mutants. These results indicate that the impaired synthesis of sucrose in rice cannot be sufficiently compensated for by the transitory starch-mediated pathways that have been found to facilitate plant growth in the equivalent Arabidopsis mutants. [source]

New severe strains of Melon necrotic spot virus: symptomatology and sequencing

PLANT PATHOLOGY, Issue 5 2005
C. Kubo
New strains of Melon necrotic spot virus (MNSV), designated MNSV-YS and MNSV-KS, caused much more severe growth retardation on melon plants than MNSV-NH, which was previously reported as the most severe strain of MNSV in Japan. MNSV-YS spread much more quickly than MNSV-NH in infected plants, and induced more severe growth retardation, even though the appearance of necrotic lesions on inoculated cotyledons was much slower. MNSV-KS had properties intermediate between those of the other two strains. The results suggest that faster-spreading strains can multiply more rapidly as a result of lower levels of activity in inducing necrotic lesions in melon plants. The complete sequences of MNSV-YS and MNSV-KS were determined, and an RT,PCR,RFLP method based on these sequences was successfully developed to detect and discriminate between the three strains. [source]

Possible human chimera detected prenatally after in vitro fertilization: a case report

PRENATAL DIAGNOSIS, Issue 11 2003
B. Simon-Bouy
Abstract Background Chimerism is the coexistence of more than one cell line in an individual, due to the fusion of originally separate zygotes. It has been very rarely described in humans. Methods A 36-year-old woman who was referred for in vitro fertilization (IVF) for unexplained infertility had three embryos transferred. Results Four weeks and five days after the transfer, ultrasound examination detected a single fetus in the uterus. Ultrasound examination at 17 weeks for metrorrhagia showed severe intrauterine growth retardation. Amniocentesis revealed a mixture of 46,XY and 46,XX clones. Histopathologic examination showed a dysmorphic fetus with female phenotype and severe growth retardation. Conclusions Although demonstration by fingerprinting has not been possible, fusion of two of the three transferred embryos (one male and one female) seems to be the most probable mechanism that could explain both cytogenetic and histopathologic observations. No chimera has yet been described after IVF. It would be interesting to collect any such observations from other IVF centers. Copyright © 2003 John Wiley & Sons, Ltd. [source]