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Molecular organisation of the quinic acid utilization (QUT) gene cluster in Aspergillus nidulans 总被引:9,自引:0,他引:9
Alastair R. Hawkins Heather K. Lamb Melanie Smith John W. Keyte Clive F. Roberts 《Molecular & general genetics : MGG》1988,214(2):224-231
Summary The functional integrity of the QUTB gene (encoding quinate dehydrogenase) has been confirmed by transformation of a qutB mutant strain. The DNA sequence of the contiguous genes QUTD (quinate permease), QUTB and QUTG (function unknown) has been determined and analysed, together with that of QUTE (catabolic 3-dehydroquinase). The QUTB sequence shows significant homology with the shikimate dehydrogenase function of the complex AROM locus of Aspergillus nidulans, and with the QA-3 quinate dehydrogenase and QA-1S (repressor) genes of Neurospora crassa. The QUTD gene shows strong homology with the N. crassa QA-Y gene and QUTG with the QA-X gene. QUTD, QUTB, and QUTG, QUTE form two pairs of divergently transcribed genes, and conserved sequence motifs identified in the two common 5 non-coding regions show significant homology with UAS
GAL
and UAS
QA
sequences of the Saccharomyces cerevisiae and N. crassa Gal and QA systems. In addition, conserved 5 sequences homologous to the mammalian CAAT box are noted and a previously unreported conserved 22 nucleotide motif is presented. 相似文献
3.
Melanie R. Maas 《Journal of industrial microbiology & biotechnology》1993,12(3-5):162-167
Summary In the processed meat industry, food safety and microbiological shelf life issues lend themselves to the use of probability modeling. Our research concentrated on predicting the effectiveness of sodium lactate as an antibotulinal agent in vacuum packaged, uncured and cured turkey breast model systems. In uncured turkey breast containing 1.4% NaCl, 0.3% Na phosphate, and 0–3% Na lactate, the antibotulinal effect of sodium lactate can be predicted using the following model: Days to toxicity = 3.13+0.39(Na lactate)2. Using cured turkey breast with 0.3% Na phosphate, 0.2% sucrose, 0–3% Na lactate, the time to toxicity can be predicted from the following model: Days to toxicity = 1.69+4.88(NaCl)–11.16(Na lactate)+7.23(Na lactate)2. Probability models have also been developed to predict the refrigerated shelf life of specific processed meat products. The usefulness of the predictive modeling for food safety and quality in the food industry will also be discussed.This paper was presented at The International Conference on the Application of Predictive Microbiology and Computer Modeling Techniques to the Food Industry, April 12–15 1992, Hyatt Regency Hotel, Tampa, FL, USA. 相似文献
4.
Autocrine production of growth factors is thought to be an essential element in the development of hemopoietic tumors in vivo. Tumor-derived cell lines frequently show this capability in vitro. It is not understood how autonomous growth in vitro is maintained by lymphoid cell lines that are not of tumorigenic origin. We have previously established human B cell clones that proliferate in serum-free media with unlimited potential. However, the cells need a critical density for continuous growth. Culture supernatant conditioned by these cell lines sustained proliferation even in low density cultures. All B cell clones analyzed were found to secrete the cytokines IL-1 alpha, IL-6, TNF-alpha, and TNF-beta whereas no activity of IL-2, IL-4, low m. w.-B cell growth factor, CSF, or IFN-gamma was recorded. In low density cultures supplemented with rIL-1 alpha, +/- IL-6, +/- TNF-alpha, and +/- TNF-beta together, B cell proliferation is maintained to the same extent as with conditioned medium. Addition of anti-sense oligonucleotides directed to the mRNA of IL-1 alpha, IL-6, and TNF-alpha, respectively, resulted in growth arrest and cell death. This effect could be prevented by supplementation with these cytokines. Scatchard plot analyses and internalization studies revealed that the cells express on their surface high affinity receptors for IL-1 alpha, IL-6, and TNF, respectively, and internalize the cytokines from the supernatant. These results demonstrate that (i) autonomous growth of immortalized B cells is maintained by secretion and reinternalization of IL-1 alpha, IL-6, TNF-alpha, and TNF-beta, (ii) these cytokines act in a synergistic fashion, and (iii) autocrine growth stimulation of human B cells in vitro does not necessarily represent their tumorigenic potential in vivo. 相似文献
5.
Aaron Mendez-Bermudez Liudmyla Lototska Melanie Pousse Florent Tessier Oliver Croce Chrysa
M Latrick Veronica Cherdyntseva Joe Nassour Jiang Xiaohua Yiming Lu Corinne Abbadie Sarantis Gagos Jing Ye Eric Gilson 《Nucleic acids research》2022,50(13):7493
Cellular senescence triggers various types of heterochromatin remodeling that contribute to aging. However, the age-related mechanisms that lead to these epigenetic alterations remain elusive. Here, we asked how two key aging hallmarks, telomere shortening and constitutive heterochromatin loss, are mechanistically connected during senescence. We show that, at the onset of senescence, pericentromeric heterochromatin is specifically dismantled consisting of chromatin decondensation, accumulation of DNA breakages, illegitimate recombination and loss of DNA. This process is caused by telomere shortening or genotoxic stress by a sequence of events starting from TP53-dependent downregulation of the telomere protective protein TRF2. The resulting loss of TRF2 at pericentromeres triggers DNA breaks activating ATM, which in turn leads to heterochromatin decondensation by releasing KAP1 and Lamin B1, recombination and satellite DNA excision found in the cytosol associated with cGAS. This TP53–TRF2 axis activates the interferon response and the formation of chromosome rearrangements when the cells escape the senescent growth arrest. Overall, these results reveal the role of TP53 as pericentromeric disassembler and define the basic principles of how a TP53-dependent senescence inducer hierarchically leads to selective pericentromeric dismantling through the downregulation of TRF2. 相似文献
6.
Every heart beat is not equal. As physiological demands of the cardiovascular system change, cardiac myocytes modulate contractile parameters including the rate and force of contraction. Adaptive responses require the sensing of biomechanical signals involving the interface between the contractile cytoskeleton (myofibrils) and the sarcolemma at specialized cell-cell junctions (intercalated discs) and cell-substrate adhesion complexes (costameres). Recent studies have shed insight into how protein complexes within cardiac myocytes sense biomechanical signals, processes required for normal adaptive or pathological responses. This new evidence suggests that complexes associated with the giant, myofibrillar protein titin sense myocyte stretch. Here, we discuss evidence supporting titin being an ideal biomechanical sensor. 相似文献
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8.
9.
Dingjiang Liu Melanie Cocco Masazumi Matsumura Da Ren Bridget Becker Richard L. Remmele Jr. David N. Brems 《Biomolecular NMR assignments》2007,1(1):93-94
Here we report the NMR resonance assignments for the reduced form of human IgG1 CH3 domain, a 26 kDa dimer in solution (residues 341–447). The assignments have been deposited in the BioMagResBank with a BMRB
accession number of 15204. 相似文献
10.
Melanie A. Rossong Pedro A. Quijón Paul V. R. Snelgrove Timothy J. Barrett Cynthia H. McKenzie Andrea Locke 《Biological invasions》2012,14(3):659-669
Invasive green crab populations initially established in Canada within the Bay of Fundy, New Brunswick in the 1950s and were present in all five Atlantic provinces by 2007. Genetic evidence suggests that the Atlantic Canadian populations originated from two separate introductions with differences in time of establishment among regions and possible population-level behavioural differences. In this study, we examine intraspecific foraging behaviour among crabs from different populations, and interspecific foraging behaviour between genetically similar crabs and juvenile lobsters. Both sets of foraging experiments involved competition for a limited food source over a 1-h period. In intraspecific match-ups, recent invaders from Newfoundland (NL) were significantly superior foragers than long-established invaders from Nova Scotia (NS) and New Brunswick (NB) populations; however, we found no differences between NL and Prince Edward Island (PE) invaders. Crabs from PE were better competitors than those from NS and NB, but these differences were not significant. Interspecific competition experiments indicated that the feeding behaviour of recent invaders (NL) and genetically similar, but long-established invaders (NS), differed in the presence of juvenile lobsters. Our study documents striking behavioural differences among populations of green crab from a small geographic region, which may reflect a combination of both genetic differences and time since establishment. These differences may result in varying impacts on newly invaded habitats. 相似文献