scholarly journals Filtration enrichment method for isolation of auxotrophic mutants of Trichoderma harzianum rifai

1999 ◽  
Vol 30 (1) ◽  
pp. 43-46
Author(s):  
Ana Maria R. Cassiolato ◽  
Itamar Soares de Melo
Keyword(s):  
Growth Rate ◽  
Trichoderma Harzianum ◽  
Genetic Research ◽  
Wild Type ◽  
Enrichment Method ◽  
Isolation Technique ◽  
Auxotrophic Mutants ◽  
Enrichment Technique ◽  
Filtration Enrichment ◽  
Similar Growth

The isolation of genetic markers, like drug resistance and auxotrophy, is a laborious but important step in genetic research. The isolation of auxotrophic mutants of Trichoderma harzianum using the filtration enrichment technique was more effective than using the total isolation technique. Most of 12 auxotrophic mutants exhibited similar growth rate and higher sporulation when compared with the wild type, but only two mutants (TWS-410 and TW5-523) could grow in 500µg/L of benomyl.

Rhizosphere competence of benomyl-tolerant mutants of Trichoderma spp.

1988 ◽  
Vol 34 (5) ◽  
pp. 694-696 ◽  
Author(s):  
Jaleed S. Ahmad ◽  
Ralph Baker
Keyword(s):  
Growth Rate ◽  
Carbon Source ◽  
Trichoderma Harzianum ◽  
Sole Carbon Source ◽  
Linear Growth ◽  
Dry Weight ◽  
Linear Growth Rate ◽  
Wild Type ◽  
Trichoderma Spp ◽  
Rhizosphere Competence

Two strains of Trichoderma harzianum and one each of T. koningii, T. polysporum, and T. viride were mutated for tolerance to the fungicide benomyl. Rhizosphere competence index of several mutants of each strain and species was determined by the rhizosphere competence assay. Most of the mutants and not their wild type parents were rhizosphere competent. When the strains and species were grown in Czapek–Dox broth for 6 days with cellulose as sole carbon source, the mutants produced significantly higher dry weight than their parent wild types. Neither the mutants nor the wild types produced biomass in glucose comparable to that in cellulose. Evidence indicates that Trichoderma spp. were induced by mutation to increase their linear growth rate and to become rhizosphere competent. Tolerance to benomyl does not seem to be a necessary attribute of rhizosphere competence.

Growth of Salmonella enterica Serovars Typhimurium and Enteritidis in Iron-Poor Media and in Meat: Role of Catecholate and Hydroxamate Siderophore Transporters

2019 ◽  
Vol 82 (4) ◽  
pp. 548-560 ◽  
Author(s):  
SAMUEL MOHAMMED CHEKABAB ◽  
MUHAMMAD ATTIQ REHMAN ◽  
XIANHUA YIN ◽  
CATHERINE CARRILLO ◽  
MARTIN MONDOR ◽  
...  
Keyword(s):  
Growth Rate ◽  
Salmonella Enterica ◽  
Salmonella Enteritidis ◽  
Chicken Breast ◽  
Wild Type ◽  
Slow Growth Rate ◽  
The Individual ◽  
Similar Growth ◽  
Media Data

ABSTRACTEnteritidis and Typhimurium are among the top Salmonella enterica serovars implicated in human salmonellosis worldwide. This study examined the individual and combined roles of catecholate-iron and hydroxamate-iron transporters in the survival in meat of Salmonella Enteritidis and Typhimurium. Catecholate–iron-III (Fe3+) and hydroxamate-Fe3+ transporter genes fepA, iroN, and fhuACDB were deleted in isolates of these serovars to generate single, double, and triple mutants. Growth rate in high- and low-iron media was compared among mutants, complements, and their wild-type parents. Susceptibility to 14 antibiotics, the ability to produce and utilize siderophores, and survival on cooked chicken breast were evaluated. In iron-poor liquid media, differences were observed between the growth characteristics of mutant Salmonella Enteritidis and Typhimurium. The double ΔiroNΔfepA and the triple ΔfhuΔiroNΔfepA mutants of Salmonella Enteritidis exhibited prolonged lag phases (λ = 9.72 and 9.53 h) and a slow growth rate (μmax = 0.35 and 0.25 h−1) similar to that of its ΔtonB mutant (λ = 10.12 h and μmax = 0.30 h−1). In Salmonella Typhimurium, double ΔiroNΔfepA and triple ΔfhuΔiroNΔfepA mutations induced a similar growth pattern as its ΔtonB mutant. Double deletions of fepA and iroN reduced the siderophore production and the use of enterobactin as an iron source. In the ΔiroNΔfepA mutant, but not in ΔfhuΔiroNΔfepA, the ferrichrome or deferrioxamine promoted growth for both serovars, confirming the specific role of the FhuACDB system in the uptake and transport of hydroxamate Fe3+. Survival of the mutants was also evaluated in a meat assay, and no difference in survival was observed among the mutants compared with wild type. This study showed differences between serovars in the importance of catecholate-iron and hydroxamate-iron uptake on Salmonella growth in iron-restricted media. Data also confirmed that both Salmonella Enteritidis and Typhimurium are well equipped to survive on cooked chicken meat, offering a rich iron condition.

scholarly journals Citrate Synthase Mutants of Agrobacterium Are Attenuated in Virulence and Display Reduced vir Gene Induction

2005 ◽  
Vol 187 (14) ◽  
pp. 4844-4852 ◽  
Author(s):  
Maneewan Suksomtip ◽  
Pu Liu ◽  
Tamara Anderson ◽  
Sumalee Tungpradabkul ◽  
Derek W. Wood ◽  
...  
Keyword(s):  
Growth Rate ◽  
Deletion Mutant ◽  
Citrate Synthase ◽  
Brucella Melitensis ◽  
Gene Induction ◽  
Wild Type ◽  
Fold Reduction ◽  
Induced Tumors ◽  
A Minor ◽  
Similar Growth

ABSTRACT A citrate synthase (CS) deletion mutant of Agrobacterium tumefaciens C58 is highly attenuated in virulence. The identity of the mutant was initially determined from its amino acid sequence, which is 68% identical to Escherichia coli and 77% identical to Brucella melitensis. The mutant lost all CS enzymatic activity, and a cloned CS gene complemented a CS mutation in Sinorhizobium. The CS mutation resulted in a 10-fold reduction in vir gene expression, which likely accounts for the attenuated virulence. When a plasmid containing a constitutive virG [virG(Con)] locus was introduced into this mutant, the level of vir gene induction was restored to nearly wild-type level. Further, the virG(Con)-complemented CS mutant strain induced tumors that were similar in size and number to those induced by the parental strain. The CS mutation resulted in only a minor reduction in growth rate in a glucose-salts medium. Both the CS mutant and the virG(Con)-complemented CS strain displayed similar growth deficiencies in a glucose-salts medium, indicating that the reduced growth rate of the CS mutant could not be responsible for the attenuated virulence. A search of the genome of A. tumefaciens C58 revealed four proteins, encoded on different replicons, with conserved CS motifs. However, only the locus that when mutated resulted in an attenuated phenotype has CS activity. Mutations in the other three loci did not result in attenuated virulence and any loss of CS activity, and none were able to complement the CS mutation in Sinorhizobium. The function of these loci remains unknown.

scholarly journals Effects of cofD gene knock-out on the methanogenesis of Methanobrevibacter ruminantium

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jian Ma ◽  
Xueying Wang ◽  
Ting Zhou ◽  
Rui Hu ◽  
Huawei Zou ◽  
...  
Keyword(s):  
Growth Rate ◽  
Specific Growth ◽  
Production Capacity ◽  
Maximum Amount ◽  
Logarithmic Phase ◽  
Wild Type ◽  
Knock Out ◽  
Maximum Biomass ◽  
Reproductive Ability ◽  
Methanobrevibacter Ruminantium

AbstractThis study aimed to investigate the effects of cofD gene knock-out on the synthesis of coenzyme F420 and production of methane in Methanobrevibacter ruminantium (M. ruminantium). The experiment successfully constructed a cofD gene knock-out M. ruminantium via homologous recombination technology. The results showed that the logarithmic phase of mutant M. ruminantium (12 h) was lower than the wild-type (24 h). The maximum biomass and specific growth rate of mutant M. ruminantium were significantly lower (P < 0.05) than those of wild-type, and the maximum biomass of mutant M. ruminantium was approximately half of the wild-type; meanwhile, the proliferation was reduced. The synthesis amount of coenzyme F420 of M. ruminantium was significantly decreased (P < 0.05) after the cofD gene knock-out. Moreover, the maximum amount of H2 consumed and CH4 produced by mutant were 14 and 2% of wild-type M. ruminantium respectively. In conclusion, cofD gene knock-out induced the decreased growth rate and reproductive ability of M. ruminantium. Subsequently, the synthesis of coenzyme F420 was decreased. Ultimately, the production capacity of CH4 in M. ruminantium was reduced. Our research provides evidence that cofD gene plays an indispensable role in the regulation of coenzyme F420 synthesis and CH4 production in M. ruminantium.

scholarly journals Survival and mutant production induced by mutagenic agents in Metarhizium anisopliae

1995 ◽  
Vol 52 (3) ◽  
pp. 548-554 ◽  
Author(s):  
V. Kava - Cordeiro ◽  
E.A. Luna - Alves - Lima ◽  
J.L. Azevedo
Keyword(s):  
Gamma Radiation ◽  
Ultraviolet Light ◽  
Metarhizium Anisopliae ◽  
Entomopathogenic Fungus ◽  
Nitrous Acid ◽  
Wild Strain ◽  
Wild Type ◽  
Survival Curves ◽  
Auxotrophic Mutants ◽  
Morphological Mutants

A wild strain of Metarhizium anisopliae, an entomopathogenic fungus, was submitted to three mutagenic agents: gamma radiation, ultraviolet light and nitrous acid. Survival curves were obtained and mutants were selected using different mutagenic doses which gave 1 to 5% survival. Morphological and auxotrophic mutants were isolated. Morphological mutants were grouped in a class with yellow conidia and other with pale vinaceous conidia as opposed to the green wild type conidia. Auxotrophic mutants had requirements for vitamin and aminoacid biosynthesis. More than 58% of the total auxotrophk mutants required proline/aipnine. Gamma radiation showed to be the most efficient mutagenic agent giving 0.2% of auxotrophk mutants followed by ultraviolet light (0.12%) and nitrous acid (0.06%).The conidial colour and auxotrophk mutants isolated until now from M. anisopliae were reviewed.

scholarly journals The Constitutive Centromere Component CENP-50 Is Required for Recovery from Spindle Damage

2005 ◽  
Vol 25 (23) ◽  
pp. 10315-10328 ◽  
Author(s):  
Yukinori Minoshima ◽  
Tetsuya Hori ◽  
Masahiro Okada ◽  
Hiroshi Kimura ◽  
Tokuko Haraguchi ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Growth Rate ◽  
Mitotic Checkpoint ◽  
Loss Of Function ◽  
Wild Type ◽  
Centromere Function ◽  
Dt40 Cells ◽  
Precise Role ◽  
Chicken Dt40 Cell

ABSTRACT We identified CENP-50 as a novel kinetochore component. We found that CENP-50 is a constitutive component of the centromere that colocalizes with CENP-A and CENP-H throughout the cell cycle in vertebrate cells. To determine the precise role of CENP-50, we examined its role in centromere function by generating a loss-of-function mutant in the chicken DT40 cell line. The CENP-50 knockout was not lethal; however, the growth rate of cells with this mutation was slower than that of wild-type cells. We observed that the time for CENP-50-deficient cells to complete mitosis was longer than that for wild-type cells. Centromeric localization of CENP-50 was abolished in both CENP-H- and CENP-I-deficient cells. Coimmunoprecipitation experiments revealed that CENP-50 interacted with the CENP-H/CENP-I complex in chicken DT40 cells. We also observed severe mitotic defects in CENP-50-deficient cells with apparent premature sister chromatid separation when the mitotic checkpoint was activated, indicating that CENP-50 is required for recovery from spindle damage.

Influence of homologous phasins (PhaP) on PHA accumulation and regulation of their expression by the transcriptional repressor PhaR in Ralstonia eutropha H16

Microbiology ◽  
2005 ◽  
Vol 151 (3) ◽  
pp. 825-833 ◽  
Author(s):  
Markus Pötter ◽  
Helena Müller ◽  
Alexander Steinbüchel
Keyword(s):  
Ralstonia Eutropha ◽  
Current Model ◽  
Transcriptional Repressor ◽  
Start Codon ◽  
Wild Type ◽  
Mobility Shift ◽  
Intergenic Regions ◽  
Gel Mobility Shift ◽  
Dnasei Footprinting ◽  
Similar Growth

Phasins play an important role in the formation of poly(3-hydroxybutyrate) [poly(3HB)] granules and affect their size. Recently, three homologues of the phasin protein PhaP1 were identified in Ralstonia eutropha strain H16. The functions of PhaP2, PhaP3 and PhaP4 were examined by analysis of R. eutropha H16 deletion strains (ΔphaP1, ΔphaP2, ΔphaP3, ΔphaP4, ΔphaP12, ΔphaP123 and ΔphaP1234). When cells were grown under conditions permissive for poly(3HB) accumulation, the wild-type strain and all single-phasin negative mutants (ΔphaP2, ΔphaP3 and ΔphaP4), with the exception of ΔphaP1, showed similar growth and poly(3HB) accumulation behaviour, and also the size and number of the granules were identical. The single ΔphaP1 mutant and the ΔphaP12, ΔphaP123 and ΔphaP1234 mutants showed an almost identical growth behaviour; however, they accumulated poly(3HB) at a significantly lower level than wild-type and the single ΔphaP2, ΔphaP3 or ΔphaP4 mutants. Gel-mobility-shift assays and DNaseI footprinting experiments demonstrated the capability of the transcriptional repressor PhaR to bind to a DNA region +36 to +46 bp downstream of the phaP3 start codon. The protected sequence exhibited high similarity to the binding sites of PhaR upstream of phaP1, which were identified recently. In contrast, PhaR did not bind to the upstream or intergenic regions of phaP2 and phaP4, thus indicating that the expression of these two phasins is regulated in a different way. Our current model for the regulation of phasins in R. eutropha strain H16 was extended and confirmed.

scholarly journals Impaired Temperature Stress Response of a Streptococcus thermophilus deoD Mutant

2003 ◽  
Vol 69 (2) ◽  
pp. 1287-1289 ◽  
Author(s):  
Mario Varcamonti ◽  
Maria R. Graziano ◽  
Romilde Pezzopane ◽  
Gino Naclerio ◽  
Slavica Arsenijevic ◽  
...  
Keyword(s):  
Growth Rate ◽  
Stress Response ◽  
Heat Shock ◽  
Temperature Stress ◽  
Streptococcus Thermophilus ◽  
Wild Type ◽  
Temperature Shock ◽  
Dual Response ◽  
Survival Capacity

ABSTRACT An insertional deoD mutant of Streptococcus thermophilus strain SFi39 had a reduced growth rate at 20°C and an enhanced survival capacity to heat shock compared to the wild type, indicating that the deoD product is involved in temperature shock adaptation. We report evidence that ppGpp is implicated in this dual response.

Detection of Vibrio cholerae and Vibrio parahaemolyticus by molecular and culture based methods from source water to household container-stored water at the point-of-use in South African rural communities

2010 ◽  
Vol 61 (12) ◽  
pp. 3091-3101 ◽  
Author(s):  
V. M. Ntema ◽  
N. Potgieter ◽  
T. G. Barnard
Keyword(s):  
16S Rrna ◽  
Vibrio Cholerae ◽  
Vibrio Parahaemolyticus ◽  
Pcr Detection ◽  
Toxin Gene ◽  
Specific Method ◽  
Culturable Bacteria ◽  
Source Water ◽  
Enrichment Method ◽  
Filtration Enrichment

Detection methods for Vibrio cholerae and Vibrio parahaemolyticus which included the culture based approach with polymerase chain reaction (PCR) confirmation, PCR detection without enrichment and PCR with a pre-enrichment were developed and their performance evaluated. PCR assays targeted the SodB (V. cholerae species), Flae (V. parahaemolyticus species), 16S rRNA (Vibrio and Enterobacteriacea species) genes (Multiplex 1) and V. cholerae O1 and V. cholerae O139 rfb genes, ctxA (cholera toxin) gene and 16S rRNA gene (Multiplex 2). These methods were used to determine the occurrence of selected Vibrios in source water as well as in household container-stored water. The combination of filtration, enrichment and PCR method provided a sensitive and specific method for the detection of selected Vibrios in water samples. The PCR with a pre-enrichment method detected as few as 4–10 cfu/100 mL of selected Vibrios and PCR detection without the enrichment method detected as few as 40–100 cfu/100 mL of selected Vibrios. The inclusion of an enrichment period allows detection of culturable bacteria. As an application of the developed methods, V. cholerae and V. parahaemolyticus were detected in the source water used by the population and in the water-storage containers. The results indicate that Vibrio species in the containers could have originated from the source water and survive in biofilms inside the containers.

RHYTHMS IN BLUE-LIGHT-INDUCED CONIDIATION OF WILD TYPE AND A MUTANT STRAIN OF Trichoderma harzianum

1988 ◽  
Vol 47 (3) ◽  
pp. 425-431 ◽  
Author(s):  
GERALD F. DEITZER ◽  
BENJAMIN A. Horwitz ◽  
Jonathan Gressel
Keyword(s):  
Blue Light ◽  
Mutant Strain ◽  
Trichoderma Harzianum ◽  
Wild Type
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