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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A secreted phosphodiesterase/alkaline phosphatase, APaseD, was purified from a culture of Bacillus subtilis JH646MS. Its phosphodiesterase activity was reminiscent of an APase isolated and characterized previously. Immunoassay and N-terminal sequencing showed the two proteins to be identical. Using the first 20 amino acids of the mature protein, a BLAST search of GenBank was used to find an homologous sequence. An exact match was found but in a putative non-coding region. It was hypothesized that there was a base pair deletion in the phoD gene. A DNA fragment internal to the coding region was generated by PCR using template DNA from a strain which produced APaseD. The PCR fragment was cloned and used to interrupt the gene. Western blot analysis of the parent and the mutated strains showed that APaseD was missing in the mutant. Resequencing of the gene revealed a larger ORF encoding a protein similar in size to the 49 kDa APaseD estimated by SDS-PAGE. The promoter was then cloned, sequenced and used in phoD-lacZ promoter fusions which showed that the gene was phosphate-starvation-induced and dependent on PhoP and PhoR for expression.
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PMID:A Bacillus subtilis secreted phosphodiesterase/alkaline phosphatase is the product of a Pho regulon gene, phoD. 876 Sep 16

We have cloned and sequenced the nrd (nucleotide reductase) locus of Bacillus subtilis. The locus seems to be organized in an operon comprising four ORFs. The first three encode polypeptides highly similar to the product of the coding sequences characterizing the nrdEF operons of Enterobacteriaceae. The sequencing of the conditional lethal mutation ts-A13, localized in the nrdE cistron, and the lethality of insertional mutations targeted in the internal region of nrdE and nrdF, demonstrated the essential role of this locus. The fourth ORF, ymaB, part of the putative operon, which is not similar to any known protein, is also essential. The regulation of expression of the operon, monitored by lacZ transcriptional fusions, is similar to the regulation of the functionally relevant nrdAB operon of Escherichia coli. The operon was induced by thymidine starvation and its expression was directly or indirectly affected by RecA function. Genetic and functional analysis strongly indicates that in B. subtilis the class I ribonucleotide reductase encoded by this nrd operon is evolutionarily distant from the homologous class I enzyme of Enterobacteria.
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PMID:The Bacillus subtilis genes for ribonucleotide reductase are similar to the genes for the second class I NrdE/NrdF enzymes of Enterobacteriaceae. 896 95

Nucleotide sequence of Xanthomonas oryzae pv. oryzae (Xoo) DNA from pSM-A1 was determined and sequence analysis revealed an ORF with high homology to RecA proteins. Expression analysis using an anti-RecA antibody demonstrates that MMS treatment induces recA in Xanthomonas strains but not in an Escherichia coli harbouring cloned Xoo recA. This indicates the existence of a recA regulatory mechanism in Xanthomonas that is not function in E. coli. In Xoo, recA was highly induced by treatments with chemical mutagens, UV and peroxides, while superoxides, a thiol agent, a heavy metal and heat shock were not inducers. The increased amount of RecA induced by H2O2 or MMS treatments were due to increased transcription of recA. recA showed no growth phase or starvation regulation. The pattern of recA regulation in Xoo could play important roles in stress survival in the environment and during plant-microbe interactions.
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PMID:Characterization and expression analysis of a Xanthomonas oryzae pv. oryzae recA. 946 92

The nucleotide sequence of the gene encoding the glucose-regulated protein 78 (GRP78) of Neurospora crassa was determined. The ORF codes for a protein of 662 amino acids (72 kDa) and belongs to the heat shock protein 70 (hsp70) gene family, which is characterized by three HSP70 'signature sequences'. The grp78 gene contains 5 introns. The protein carries the ER retention signal HDEL at its carboxy terminus and is most homologous to the KAR2/GRP78 protein of Saccharomyces cerevisiae (78%) and to KAR2/BiP of Yarrowia lipolytica (76%). The expression of grp78 is constitutive and can be enhanced by starvation, treatment with tunicamycin, the calcium ionophore A23187 or elevated temperatures (40 degrees C). An uninterrupted ORF was found on the reverse cDNA strand of grp78. The putative peptide shows 47% homology to the NAD-specific glutamate dehydrogenase of Achlya klebsiana.
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PMID:Molecular analysis of a glucose-regulated gene (grp78) of Neurospora crassa. 954 20

To investigate the metabolism of (p)ppGpp in amino-acid-producing coryneform bacteria, a PCR-based strategy using degenerate consensus oligonucleotides was applied to isolate the rel gene of Corynebacterium glutamicum ATCC 13032. The gene consists of 2283 nucleotides and encodes a protein of 760 amino acids with a molecular mass of 84.4 kDa. The amino acid sequence revealed extensive similarities to the related proteins RelA and SpoT of Escherichia coli, which are known to be involved in (p)ppGpp biosynthesis and degradation. The C. glutamicum rel gene is located downstream of the apt gene encoding an adenine phosphoribosyltransferase, and an ORF with similarities to dciAE, which represents part of a dipeptide transport system in E. coli. A C. glutamicum mutant strain carrying a defined deletion in the rel gene was constructed. This mutant failed to accumulate (p)ppGpp in response to amino acid starvation. When overexpressed in E. coli, the C. glutamicum rel gene was able to reverse growth defects caused by an overexpressed relA gene. It is proposed that the C. glutamicum rel gene encodes a bifunctional enzyme with (p)ppGpp synthetase and (p)ppGpp-degrading activities.
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PMID:The role of the Corynebacterium glutamicum rel gene in (p)ppGpp metabolism. 969 18

The UTH1 gene was identified by screening a Saccharomyces cerevisiae promoter-probe gene bank for oxidative stress-responsive genes. Transcription of UTH1 was decreased by the superoxide anion and increased by hydrogen peroxide. Deletion of UTH1 did not affect the growth of grande cells, however in a rho0 background it caused retarded growth. The uth1 mutant showed increased resistance to peroxides and, in contrast, was sensitive to superoxide or the thiol oxidant diamide. Furthermore, the mutant exhibited increased survival under starvation conditions, with elevated levels of dormant cells in starved cell cultures. A multicopy plasmid containing the first half of the ORF could confer increased resistance to superoxide and increased sensitivity to peroxides/diamide/starvation on wild-type cells. The same plasmid in the uth1 background caused a highly increased mortality.
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PMID:Involvement of the Saccharomyces cerevisiae UTH1 gene in the oxidative-stress response. 979 59

Retinoblastoma tumor suppressor protein (pRB) inhibition by tumor virus oncoproteins has been attributed to the need for these viruses to promote lytic viral nucleic acid synthesis by unscheduled entry into the S phase of the cell cycle. Kaposi's sarcoma-associated herpesvirus (KSHV or HHV8) encodes a functional cyclin (vCYC) which is expressed during latency and can direct phosphorylation of pRB. We mapped the two major latent transcripts encoding vCYC, latent transcript 1 (LT1) and LT2, by cDNA sequencing, 5' rapid amplification of cDNA ends, and primer extension analyses. Both LT1 and LT2 transcripts are spliced, originate from the same start site, and encode ORF K13 (vFLIP) as well as ORF72 (vCYC). The latency-associated nuclear antigen (LANA, ORF73) is encoded by LT1 but spliced from LT2. While differential expression of the two transcripts was not found, the promoter controlling LT1/LT2 transcription is regulated in a cell cycle-dependent manner. Activities of both KSHV LT1/LT2 and huCYC D1 luciferase promoter reporters transfected into NIH 3T3 cells increase 11- and 4-fold, respectively, after release from cell cycle arrest by serum starvation. Further, vCYC and huCYC D2 mRNA levels are low in naturally infected BCBL-1 cells arrested in late G1 with L-mimosine but increase in parallel during a 24-h period after release from cell cycle arrest. Cell cycle regulation of KSHV vCYC expression mimics cellular D cyclin regulation and may maintain infected cell cycling. This is consistent with an alternative hypothesis that tumor viruses have developed specific responses to innate cellular defenses against latent virus infection that include pRB-induced cell cycle arrest.
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PMID:Characterization and cell cycle regulation of the major Kaposi's sarcoma-associated herpesvirus (human herpesvirus 8) latent genes and their promoter. 988 49

The European Functional Analysis Network (EUROFAN) is systematically analysing the function of novel Saccharomyces cerevisiae genes revealed by genome sequencing. As part of this effort our consortium has performed a detailed transcript analysis for 250 novel ORFs on chromosome XIV. All transcripts were quantified by Northern analysis under three quasi-steady-state conditions (exponential growth on rich fermentative, rich non-fermentative, and minimal fermentative media) and eight transient conditions (glucose derepression, glucose upshift, stationary phase, nitrogen starvation, osmo-stress, heat-shock, and two control conditions). Transcripts were detected for 82% of the 250 ORFs, and only one ORF did not yield a transcript of the expected length (YNL285w). Transcripts ranged from low (62%), moderate (16%) to high abundance (2%) relative to the ACT1 mRNA. The levels of 73% of the 206 chromosome XIV transcripts detected fluctuated in response to the transient states tested. However, only a small number responded strongly to the transients: eight ORFs were induced upon glucose upshift; five were repressed by glucose; six were induced in response to nitrogen starvation; three were induced in stationary phase; five were induced by osmo-stress; four were induced by heat-shock. These data provide useful clues about the general function of these ORFs and add to our understanding of gene regulation on a genome-wide basis.
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PMID:Transcript analysis of 250 novel yeast genes from chromosome XIV. 1020 92

We have isolated the pgmB gene from Aspergillus nidulans, which encodes a phosphoglucomutase, one of the key enzymes in carbohydrate metabolism. The pgmB gene is located on chromosome VII and its ORF encodes 557 amino acids. Mutant phenotypes were analysed by expression of high levels of pgmB antisense RNA, which lead to a loss of detectable levels of sense RNA. Under conditions of antisense RNA expression, a 30% reduction in the growth rate was observed in comparison to wild-type. On the enzyme level, expression of pgmB antisense RNA resulted in a 35% reduction in total phosphoglucomutase activity. Two pgmB mRNAs were observed under all conditions tested and differ with respect to the location of the poly(A) site. Expression of pgmB driven by the GAL1 promoter in Saccharomyces cerevisiae complemented the growth phenotype of a pgm2delta mutant strain and suppressed the sensitivity of a gcn4delta mutant strain to amino acid starvation in the presence of galactose. Cultivation of A. nidulans in the presence of glucose or galactose as carbon source did not affect transcription of pgmB. However, amino acid starvation conditions resulted in a six-fold reduction in the level of pgmB mRNA, while genes for amino acid biosynthesis showed increased transcription. Transcription of pgmB was low during hyphal growth and in the sexual phase of development, but was significantly increased during the asexual stage of the A. nidulans life cycle.
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PMID:Developmental and metabolic regulation of the phosphoglucomutase-encoding gene, pgmB, of Aspergillus nidulans. 1066 61

The Saccharomyces cerevisiae genome database contains two ORFs with homology to aquaporins, AQY1 and AQY2. Aqy1p has been shown to be a functional aquaporin in some strains, such as Sigma1278b. AQY2 is disrupted by a stop codon in most strains; however, Sigma1278b has an intact ORF. Because Sigma1278b Aqy2p has an intracellular localization in Xenopus oocytes and in yeast, other strains of yeast were examined. Aqy2p from Saccharomyces chevalieri has a single amino acid in the third transmembrane domain (Ser-141) that differs from Sigma1278b Aqy2p (Pro-141). S. chevalieri Aqy2p is a functional water channel in oocytes and traffics to the plasma membrane of yeast. The Sigma1278b parental strain, the aqy1-aqy2 double null yeast, and null yeast expressing S. chevalieri Aqy2p were examined under various conditions. Comparison of these strains revealed that the aquaporin null cells were more aggregated and their surface was more hydrophobic. As a result, the aquaporin null cells were more flocculent and more efficient at haploid invasive growth. Despite its primary intracellular localization, Sigma1278b Aqy2p plays a role in yeast similar to Aqy1p and S. chevalieri Aqy2p. In addition, Aqy1p and Aqy2p can affect cell surface properties and may provide an advantage by dispersing the cells during starvation or during sexual reproduction.
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PMID:Aquaporins in Saccharomyces: Characterization of a second functional water channel protein. 1115 84


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