scholarly journals Co-application of Difenoconazole with Thymol Results in Suppression of a Parastagonospora Nodorum Mutant Strain Resistant to this Triazole

2019 ◽  
Author(s):  
M I Kartashov ◽  
L A Shcherbakova ◽  
N V Statsyuk ◽  
V G Dzhavakhiya
Keyword(s):  
Mutant Strain ◽  
In Vitro Study ◽  
Potato Dextrose Agar ◽  
Sensitive Strain ◽  
Resistant Isolate ◽  
Leaf Blotch ◽  
Low Sensitivity ◽  
Parastagonospora Nodorum ◽  
Principal Possibility

Results of in vitro study of thymol, a natural chemosensitizer, as a potential agent for overcoming of difenoconazole resistance of Parastagonospora nodorum causing glume and leaf blotch of wheat are first reported. The level of difenoconazole resistance of a natural mutant PNm1 strain with low sensitivity to the Dividend fungicide (a.i. difenoconazole) was determined by the cultivation of this isolate on potato dextrose agar in the presence of the fungicide at sub-lethal and lethal (in relation to the initial fungicide-sensitive strain) concentrations. A principal possibility of the thymol use to overcome resistance of P. nodorum to DMI (demethylation inhibitors) fungicides is shown. Co-application of this compound with Dividend SC, 3 % resulted in a significant reduction of resistance of the mutant strain and enhancement of its sensitivity to difenoconazole up to the level corresponding to the initial non-resistant isolate.

scholarly journals The effects of flubendazole and its metabolites on the larval development of Haemonchus contortus (Nematoda: Trichostrongylidae): an in vitro study

2010 ◽  
Vol 47 (4) ◽  
pp. 269-272 ◽  
Author(s):  
H. Bártíková ◽  
L. Skálová ◽  
J. Lamka ◽  
B. Szotáková ◽  
M. Várady
Keyword(s):  
Larval Development ◽  
Haemonchus Contortus ◽  
Anthelmintic Activity ◽  
In Vitro Study ◽  
Lethal Concentration ◽  
Resistant Isolate ◽  
Susceptible Isolate ◽  
Marked Resistance ◽  
Larval Development Test

AbstractThe anthelmintic effects of flubendazole (FLU), its two main metabolites reduced flubendazole (FLU-R) and hydrolyzed flubendazole (FLU-H), and thiabendazole (TBZ) were compared using an in vitro larval development test in two isolates of Haemonchus contortus, a fully susceptible isolate (HCS) and a multi-resistant isolate (HCR). Results were quantified as 50 % lethal concentration (LC50), 99 % lethal concentration (LC99), efficacy factor (EF), and resistance factor (RF). For HCS, both LC50 and LC99 of FLU were lower than those of the reference TBZ. The anthelmintic activity of FLU-R in HCS and HCR was 13 and 6 times lower than the activity of FLU, respectively. The anthelmintic activity of FLU-H was negligible (approximately 363–853 times lower) compared to that of FLU. Although a marked resistance of the HCR isolate to TBZ was confirmed, only a low tolerance to FLU-R and slightly higher tolerance to FLU were found.

scholarly journals An In-Vitro Study of Molecular Effects of a Combination Treat-ment with Antibiotics and Nanofluid Containing Carbon Nano-tubes on Klebsiella pneumoniae

2021 ◽  
Author(s):  
Maryam Mehdizadeh ◽  
Mojgan Sheikhpour ◽  
Iman Salahshourifar ◽  
Seyed Davar Siadat ◽  
Parvaneh Saffarian
Keyword(s):  
Klebsiella Pneumoniae ◽  
Virulence Genes ◽  
Ultrasonic Method ◽  
Virulence Gene ◽  
In Vitro Study ◽  
Negative Control ◽  
Resistant Isolate ◽  
Simultaneous Treatment ◽  
Virulence Gene Expression

Background: We aimed to prepare a nanofluid, containing f-MWCNTs, and investigate the antibacterial efficacy of f-MWCNTs+ ciprofloxacin (cip) on Klebsiella pneumoniae by evaluating the virulence gene expression. Methods: This study was carried out from 2019 to 2020, in the Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran. The nanofluid containing antibiotic and f-MWCNTs were prepared by the ultrasonic method. The minimum inhibitory concentrations (MICs) of ciprofloxacin and f-MWCNTs were determined using the broth micro dilution MIC tests. For examining the antibacterial effects, the expression level of virulence genes, under the influence of f-MWCNTs, was evaluated by a real-time PCR. Results: The effect of 8 µg/ml ciprofloxacin + 400 µg/ml f-MWCNTs, completely inhibited the growth of the resistant isolate of K. pneumoniae, while, in the ATCC 700,603 isolate, 2 µg/ml ciprofloxacin with 100 µg/ml f-MWCNT could inhibit a bacterial growth. In the resistant K. pneumoniae clinical isolate, after f-MWCNT+cip treatment, the expression of fimA, fimD, wza, and wzi genes was significantly downregulated, compared to the ciprofloxacin treatment, and upregulated, compared to the negative control. For the ATCC 700,603 isolate treated with f-MWCNT+cip, the expression of fimA, fimD and wza virulence genes showed upregulation, compared to the negative control and downregulated in comparison with the ciprofloxacin treatment. Conclusion: Simultaneous treatment of resistant isolate of K. pneumoniae with f-MWCNTs +antibiotic could improve the effectiveness of antibiotic at lower doses, due to the reduced expression of virulence genes in comparison with antibiotic treatment, besides the increased cell wall permeability to antibiotics.

scholarly journals The effect of sinefungin on the macromolecular biosynthesis of Leishmania species

2018 ◽  
Vol 49 (2) ◽  
pp. 137
Author(s):  
A. TZORA (Α. ΤΖΩΡΑ) ◽  
F. LAWRENCE ◽  
M. ROBERT-GERO
Keyword(s):  
Dna Synthesis ◽  
Mode Of Action ◽  
Rna Synthesis ◽  
In Vitro Study ◽  
Leishmania Species ◽  
Sensitive Strain ◽  
Vitro Study ◽  
No Inhibition ◽  
Main Target

The aim of the work presented here was the in vitro study of the action of the antibiotic sinefungin on the macromolecules DNA, RNA and the proteins of different isolates of Leismannia spp. in relation to the resistance or to the sensitivity of the strains examined. The mode of action of sinefungin of the Leishmania strains was detected by incorporating radiolabeled thymidine, uridine and leucine into promastigote forms, to study the synthesis of DNA, RNA and proteins respectively. In the sensitive strain L. tropica a statistically significant reduction of the rate of incorporation of thymidine to the DNA of the parasite, resulted to a 64% inhibition of leishmanial DNA synthesis by sinefungin at a concentration of 2.6 mM, when the time of action of the drug was 24 hours. In the sensitive strain L. tropica the reduction of the rate of incorporation of thymidine was depended on the concentration and the time of action of the drug. No inhibition of leishmanial RNA synthesis was observed. Our research showed that the action of the antibiotic sinefungin to the macromolecular biosynthesis of the protozoan Leishmania is independent of the strain and is strongly related with the expression of the sensitivity and the resistance of the strain. The main target of the antibiotic examined was the DNA of the Leishmania strains sensitive to the drug.

scholarly journals Effect of Fungicides on Colony Growth of Colletotrichum Lindemuthianum (Sacc. & Magn.) Scrib.

2008 ◽  
Vol 48 (2) ◽  
pp. 201-212
Author(s):  
Juliana Sartori ◽  
Antonio Maringoni
Keyword(s):  
Culture Medium ◽  
High Sensitivity ◽  
Colony Growth ◽  
Potato Dextrose Agar ◽  
Colletotrichum Lindemuthianum ◽  
Cross Resistance ◽  
Agar Culture ◽  
Thiophanate Methyl ◽  
Low Sensitivity

Effect of Fungicides on Colony Growth ofColletotrichum Lindemuthianum(Sacc. & Magn.) Scrib.Colletotrichum lindemuthianum(Sacc. & Magn.) Scrib. is the causal agent of the anthracnose of common bean (Phaseolus vulgarisL.), a fungal disease of a great significance in brazilian bean cultures. The goals of this work were to evaluate thein vitrocolony growth and to determine the ED50interval of twentyC. lindemuthianumisolates from different regions of Brazil to five fungicides of different active ingredients and to some blendings (carbendazim, chlorothalonil, thiophanate-methyl, chlorothalonil + thiophanate-methyl, trifloxystrobin, propiconazole and trifloxystrobin + propiconazole), at concentrations of 0, 1, 10, 100 and 1000 μg/ml, in a potato-dextrose-agar culture medium. The results revealed seven isolates with low sensitivity to carbendazim and thiophanate-methyl (ED50interval greater than 1000 μg/ml) thus suggesting cross-resistance. Isolate sensitivity to chlorothalonil ranged from ED50interval less than 1 μg/ml to greater than 1000 μg/ml. Those isolates with high sensitivity to thiophanate-methyl, ED50interval less than 1 μg/ml, did also show it with respect to chlorothalonil + thiophanate-methyl. Sixteen isolates showed a high sensitivity to trifloxystrobin with a ED50interval less than 1 μg/ml. Nineteen isolates ofC. lindemuthianumshowed high sensitivity to propiconazole and to trifloxystrobin + propiconazole with ED50interval less than 1 μg/ml. Isolates with low sensitivity to carbendazim and thiophanate-methyl were sensitive to propiconazole and to trifloxystrobin + propiconazole. Variability was found in the sensitivity of the colony growth ofC. lindemuthianumisolates from different regions of Brazil to the fungicides evaluated.

scholarly journals Validity of staining and marginal ditching as criteria for diagnosis of secondary caries around occlusal amalgam restorations: an in vitro study

2009 ◽  
Vol 20 (4) ◽  
pp. 307-313 ◽  
Author(s):  
Claudia Silami Magalhães ◽  
Amanda Beatriz Dahdah Aniceto de Freitas ◽  
Allyson Nogueira Moreira ◽  
Efigênia Ferreira Ferreira
Keyword(s):  
Evaluation Criteria ◽  
In Vitro Study ◽  
Likelihood Ratios ◽  
Human Teeth ◽  
Secondary Caries ◽  
Predictive Values ◽  
Criteria For Diagnosis ◽  
Low Sensitivity ◽  
Amalgam Restorations

This study determined the validity of marginal ditching and staining as criteria for the diagnosis of secondary caries around amalgam restorations. One hundred and twenty-four Class I amalgam restorations on extracted human teeth were submitted to standardized clinical examinations. A calibrated examiner recorded the presence of ditching in the tooth/restoration interface, the occurrence of bluish-grey staining on the occlusal surface, and their relationship with the presence and severity of secondary carious lesions. Examinations were repeated after 4 days to calculate the intra-examiner reliability. Stereomicroscopic inspection of the serial tooth sections was used as the gold-standard. Six teeth were lost during the study. Of the 118 remaining teeth, 19 (16%) showed occlusal bluish-grey staining and 26 showed more than 0.20 mm wide marginal ditches. Of the latter, 14 presented narrow ditches (0.20-0.45 mm), while 12 presented wide ditches (0.45 mm). The evaluation criteria presented low sensitivity and positive predictive values. Positive and negative likelihood ratios showed that the criteria exhibited, indistinctly, the same odds to determine a positive or negative result for a diseased or healthy tooth. It was concluded that marginal ditching and staining were not valid criteria for the diagnosis of secondary caries around occlusal amalgam restorations.

scholarly journals Characterization of an operon required for growth on cellobiose in Clostridioides difficile

2021 ◽  
Author(s):  
Md Kamrul Hasan ◽  
Babita Adhikari Dhungel ◽  
Revathi Govind
Keyword(s):  
Mutant Strain ◽  
Gene Knockout ◽  
Recurrent Infection ◽  
In Vitro Study ◽  
Upstream Region ◽  
Infection Model ◽  
Cellobiose Metabolism

Cellobiose metabolism is linked to the virulence properties in numerous bacterial pathogens. Here, we characterized a putative cellobiose PTS operon of Clostridiodes difficile to investigate the role of cellobiose metabolism in C. difficile pathogenesis. Our gene knockout experiments demonstrated that the putative cellobiose operon enables uptake of cellobiose into C. difficile and allows growth when cellobiose is provided as the sole carbon source in minimal medium. Additionally, using reporter gene fusion assays and DNA pull-down experiments, we show that its transcription is regulated by CelR, a novel transcriptional repressor protein, which directly binds to the upstream region of the cellobiose operon to control its expression. We have also identified cellobiose metabolism to play a significant role in C. difficile physiology as observed by the reduction of sporulation efficiency when cellobiose uptake was compromised in the mutant strain. In corroboration to in vitro study findings, our in vivo hamster challenge experiment showed a significant reduction of pathogenicity by the cellobiose mutant strain in both the primary and the recurrent infection model- substantiating the role of cellobiose metabolism in C. difficile pathogenesis.

scholarly journals First Report of Leaf Blotch Caused by Marssonina coronaria on Apple in Italy

Plant Disease ◽  
2003 ◽  
Vol 87 (8) ◽  
pp. 1005-1005 ◽  
Author(s):  
G. Tamietti ◽  
A. Matta
Keyword(s):  
Potato Dextrose Agar ◽  
Leaf Blotch ◽  
Marssonina Coronaria ◽  
Golden Delicious ◽  
Pure Cultures ◽  
Mist Chamber ◽  
Minor Disease ◽  
Low Sensitivity ◽  
A Minor ◽  
Diplocarpon Mali

During the early summers of 2001 and 2002, in Forno Canavese in northwest Italy, a leaf disease was observed on the old apple cv. Furnas in a domestic orchard. Lesions on the upper side of the leaf were brownish, irregular in size and shape with somewhat dendritic margins, became black, and often coalesced with time. On the underside, lesions were smaller with more definite margins. Beginning in July, scattered acervuli (95 to 170 μm) were observed erupting through the epidermis on the upper side of leaves. Conidia were ampule shaped, 1-septate, constricted at the septum, hyaline, guttulate, and 6.1 to 8.4 × 14.6 to 22.0 μm. Severely diseased leaves abscised prematurely. The fungus was identified as Marssonina coronaria (Ellis & J.J. Davis) J.J. Davis, teleomorph Diplocarpon mali (1) although the conidia were slightly shorter than those originally described for this fungus. Monoconidial isolates were obtained by spreading mini-suspensions of conidia taken from acervuli on malt agar (MA) and transferring single-germinated conidia to MA, potato dextrose agar, V8 agar, or apple leaf agar (ALA). The fungus grew slowly, producing small colonies on V8 and ALA only. On ALA medium, after 3 months incubation at 20 to 22°C, the colonies were 5 to 7 mm in diameter with light brown, irregular margins and dark brown centers bearing acervuli. Conidia from pure cultures were collected, suspended in sterile, distilled water (250,000 ml-1), and sprayed on the leaves of three ‘Golden Delicious’ apple shoots maintained in a mist chamber at 20 to 25°C for 2 weeks. In two independent experiments, the fungus reproduced symptoms like those observed on ‘Furnas’ and was reisolated from acervuli. No symptoms were observed on water-treated controls. To our knowledge, apple leaf blotch has not previously been reported in Italy. Although now it is a minor disease, it could become more important in sustainable crops because of its relatively low sensitivity to copper fungicides (2), the only products that can be used under that program. References: (1) Y. Harada et al. Ann. Phytopathol. Soc. Jpn. 40:412, 1974. (2) J. Ruide et al. China Fruits 2:51, 1997.

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