A total of 38.0 Mb of publicly available DNA sequence in Neurospora crassa was researched for mono- to hexanucleotide simple sequence repeats (SSR or microsatellite) to determine the type, size and frequency. A total ...A total of 38.0 Mb of publicly available DNA sequence in Neurospora crassa was researched for mono- to hexanucleotide simple sequence repeats (SSR or microsatellite) to determine the type, size and frequency. A total of 14 788 SSRs were observed in the whole genomic DNA sequence, about one every 2.57 kb, with the criteria of SSR length >15 bp and 80% matches. The most abundant microsatellite was trinucleotide repeat, the number was 4 729, followed by hexanucleotide and mononucleotide repeats, the numbers were 2 940 and 2 489 respectively, and the least abundance was dinucleotide repeat, only 691 were found. Among the 10 082 ORFs, 4 094 SSRs were harbored in 2 373 ORF (no intron) of the organism. One thousand and fifty six ORFs harbored only one SSR. Similar with other organisms, tri- and hexanucleotide repeats were predominant in ORFs, 54.1 and 48.8% of tri- and hexanucleotide repeats were distributed in ORF region. The density of these two motifs was overpresented in coding regions, because ORF region and coding region constitutes only 46 and 38.3% of genomic sequence, respectively. Upstream and downstream 300 bp of regulatory regions were high density regions of SSRs, particularly density of pentanucleotide SSR in upstream region was as high as five times of average density in genomic DNA, density of di- and tetranucleotide SSR was also more than two times of average density. The density of penta-, tetra-, di- and mononucleotide SSRs was relatively higher than average density. There were 47 SSRs in mitochondria 64 840 bp DNA sequence, their distribution is similar with genomic DNA sequence. These results suggested that SSRs were clustered in regulatory regions of genomic DNA.展开更多
Objective:To isolate and demonstrate the mechanism of metal transport in cobalt-sensitive mutant(CSM)of Neurospora crassa(N.crassa).Methods:Isolation of CSM of N.crassa,I_(50)determination,growth measurements,metal io...Objective:To isolate and demonstrate the mechanism of metal transport in cobalt-sensitive mutant(CSM)of Neurospora crassa(N.crassa).Methods:Isolation of CSM of N.crassa,I_(50)determination,growth measurements,metal ion uptake studies and sexual crosses were performed to determine the mechanism of sensitivity and locus.Results:CSMs of N.crassa were isolated by mutagenesis with diethyl sulfate.More than 500 isolates were screened and out of these isolates,CSM-I was 5-fold and CSM-II was 10-fold sensitive to Co on liquid medium as compared to the wild type.Compositional analysis of cell wall revealed the decrease in total phosphate content.N.crassa CSM bound much less cobalt to cell wall fraction than wild type.The data indicated closer linkage between resistance and mating type locus(mat),which is,located on LG I.Conclusions:A CSM of N.crassa is 5-fold more sensitive than wild type and cross sensitive to nickel and copper and hyper-accumulates 2-4 fold more toxic metal ions over wild type.The mechanism for sensitivity is decreased in cobalt-binding to cell wall fraction and increased intracellular uptake.N.crassa-acon-3 morphologically resembles the CSM,cobalt-sensitive and maps to similar locus.展开更多
[Objective] This study aimed to investigate the regulatory mechanisms of carotenoid biosynthesis in Neurospora crassa. [Method] Gene knockout mutants pro- ducing less carotenoid were screened from 6 087 mutants; the y...[Objective] This study aimed to investigate the regulatory mechanisms of carotenoid biosynthesis in Neurospora crassa. [Method] Gene knockout mutants pro- ducing less carotenoid were screened from 6 087 mutants; the yield of carotenoid and asexual spore was measured; finally fluorescent quantitative real-time PCR was adopted to analyze the transcription of genes related to carotenoid synthesis and asexual sporulation, [Result] Six knockout mutants produced less carotenoid. In one of them, the yield of both carotenoid and asexual spore reduced, because the gene which encodes an ATP-dependent chromatin remodelling complex ATPase chain ISW1 was knocked out. This gene was named /ca-1 in this study. And the /ca-1 deletion result- ed in a reduction of 88% in conidial production and a decrease of 81% in carotenoid production. [Conclusion] The Ica-1 positively regulates the carotenoid syn- thesis and asexual sporulation in N. crassa.展开更多
基金the National Natural Science Foundation of China(30360061) Natural Science Foundation of Yunnan Province of China(1999一c0008z).
文摘A total of 38.0 Mb of publicly available DNA sequence in Neurospora crassa was researched for mono- to hexanucleotide simple sequence repeats (SSR or microsatellite) to determine the type, size and frequency. A total of 14 788 SSRs were observed in the whole genomic DNA sequence, about one every 2.57 kb, with the criteria of SSR length >15 bp and 80% matches. The most abundant microsatellite was trinucleotide repeat, the number was 4 729, followed by hexanucleotide and mononucleotide repeats, the numbers were 2 940 and 2 489 respectively, and the least abundance was dinucleotide repeat, only 691 were found. Among the 10 082 ORFs, 4 094 SSRs were harbored in 2 373 ORF (no intron) of the organism. One thousand and fifty six ORFs harbored only one SSR. Similar with other organisms, tri- and hexanucleotide repeats were predominant in ORFs, 54.1 and 48.8% of tri- and hexanucleotide repeats were distributed in ORF region. The density of these two motifs was overpresented in coding regions, because ORF region and coding region constitutes only 46 and 38.3% of genomic sequence, respectively. Upstream and downstream 300 bp of regulatory regions were high density regions of SSRs, particularly density of pentanucleotide SSR in upstream region was as high as five times of average density in genomic DNA, density of di- and tetranucleotide SSR was also more than two times of average density. The density of penta-, tetra-, di- and mononucleotide SSRs was relatively higher than average density. There were 47 SSRs in mitochondria 64 840 bp DNA sequence, their distribution is similar with genomic DNA sequence. These results suggested that SSRs were clustered in regulatory regions of genomic DNA.
文摘Objective:To isolate and demonstrate the mechanism of metal transport in cobalt-sensitive mutant(CSM)of Neurospora crassa(N.crassa).Methods:Isolation of CSM of N.crassa,I_(50)determination,growth measurements,metal ion uptake studies and sexual crosses were performed to determine the mechanism of sensitivity and locus.Results:CSMs of N.crassa were isolated by mutagenesis with diethyl sulfate.More than 500 isolates were screened and out of these isolates,CSM-I was 5-fold and CSM-II was 10-fold sensitive to Co on liquid medium as compared to the wild type.Compositional analysis of cell wall revealed the decrease in total phosphate content.N.crassa CSM bound much less cobalt to cell wall fraction than wild type.The data indicated closer linkage between resistance and mating type locus(mat),which is,located on LG I.Conclusions:A CSM of N.crassa is 5-fold more sensitive than wild type and cross sensitive to nickel and copper and hyper-accumulates 2-4 fold more toxic metal ions over wild type.The mechanism for sensitivity is decreased in cobalt-binding to cell wall fraction and increased intracellular uptake.N.crassa-acon-3 morphologically resembles the CSM,cobalt-sensitive and maps to similar locus.
基金Supported by the National Natural Science Foundation of China (31000551 30970127)~~
文摘[Objective] This study aimed to investigate the regulatory mechanisms of carotenoid biosynthesis in Neurospora crassa. [Method] Gene knockout mutants pro- ducing less carotenoid were screened from 6 087 mutants; the yield of carotenoid and asexual spore was measured; finally fluorescent quantitative real-time PCR was adopted to analyze the transcription of genes related to carotenoid synthesis and asexual sporulation, [Result] Six knockout mutants produced less carotenoid. In one of them, the yield of both carotenoid and asexual spore reduced, because the gene which encodes an ATP-dependent chromatin remodelling complex ATPase chain ISW1 was knocked out. This gene was named /ca-1 in this study. And the /ca-1 deletion result- ed in a reduction of 88% in conidial production and a decrease of 81% in carotenoid production. [Conclusion] The Ica-1 positively regulates the carotenoid syn- thesis and asexual sporulation in N. crassa.
