serial dilution method
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2022 ◽  
Vol 98 (6) ◽  
pp. 671-684
Author(s):  
P. V. Slukin ◽  
E. I. Astashkin ◽  
E. M. Aslanyan ◽  
M. G. Ershova ◽  
E. D. Poletaeva ◽  
...  

Objective. Urinary tract infections (UTIs) caused by uropathogenic Escherichia coli (UPEC) affect 150 million people annually.Purpose: Characteristics of non-hospital strains of UPEC isolated from patients with UTI in Yaroslavl in 2016– 2017.Materials and methods. Susceptibility of UPEC strains (n = 20) to antibacterials was measured by the serial dilution method; the antibiotic resistance and virulence genes, phylogroups, O-serogroups and sequence types were identified by PCR and whole genome sequencing. The virulence of the strains was studied using the model of Galleria mellonella larvae.Results. UPEC strains were classified as resistant (n = 11) and multi-drug resistant (n = 9) pathogens. Betalactamase genes blaTEM (n = 10), blaCTX-M (n = 6), class 1 integrons (n = 8), and gene cassettes dfrA17-aadA5 (n = 2), dfrA1 (n = 1) and aacA4-cmlA1 (n = 1) were identified. UPEC-virulence genetic determinants coding adhesins fimH, papG, sfaS, focG, afa/draBC, csgA, siderophores iroN, fyuA, iutA, counteracting factors of host immunity ompT, traT, toxins hlyA, cnf1, usp, capsule transporter kpsMTII, colicin cvaC, and pathogenicity islands I536, II536, III536, IV536, IIJ96 и IICFT073 were detected. Highly virulent and slightly virulent for G. mellonella larvae UPEC strains were obtained with LD50 104–105 and 106–107 CFU, respectively. The phylogroups A, B1, B2, E and F, serogroups О2, О4, О6, O9, O11, О15, О18, О25, О75 and O89, known sequence types ST14, ST58, ST69, ST73, ST93, ST127, ST131, ST-141, ST165, ST297, ST457, ST537, ST744, ST1434 and novel ST9239 and ST10102 were revealed.Conclusions. The identified genetic diversity of non-hospital UPEC strains is consistent with the observed global trend in the spread of human pathogens, which are characterized with both high virulence and multiple drug resistance. This makes possible to assess prospectively the current epidemiological situation, give a forecast for its development in the future, as well as determine the optimal therapeutic options.


Author(s):  
Neeharika Yamsani ◽  
Raja Sundararajan

Aim: The study aims to design & synthesize novel thiazole derivatives as potent antitubercular agents with minimal side effects. Background: The emergence and rapid spread of multi-drug resistant infectious microbial flora embracing a variety of bacterial as well as mycobacterium strains are causing a threat to public health worldwide. Objective: Owing to the importance, we designed compounds with thiazole functionality coupled with Schiff base and thiosemicarbazide, predicted the molecular properties and antitubercular potency of designed compounds by the in-silico method, and synthesized fifteen novel thiazole analogs, characterized and tested in vivo antitubercular, antibacterial and antioxidant potencies. Methods: Molinspiration online tool was used to predict the molecular properties and molecular docking was used to predict the antitubercular potency. FT-IR, 1H-NMR, 13C-NMR, Mass spectroscopy and bases of elemental analysis are employed to confirm the structure of compounds. 10-Fold serial dilution method, agar streak dilution test and DPPH radical scavenging methods are used to estimate antitubercular, antibacterial and antioxidant potency of title analogs, respectively. Results: Multi-step synthesis was used to synthesize a variety of novel thiazole derivatives coupled with Schiff base and thiosemicarbazide. Synthesized title compounds displayed a varying degree of antitubercular, antibacterial and antioxidant activities (mild to good). The title compounds possessing deactivating group exhibited superior activities than activating group, while unsubstituted analogs displayed intermediate activities. In addition, para-substituted analogs showed slightly higher activity than the corresponding meta substituted analogs. Conclusion: Among fifteen tested title compounds, the potent compound of this series was found to be 1-(4-nitrobenzylidene)-4-(4-(4-methoxyphenyl)thiazol-2-yl)thiosemicarbazide (BTS14), which might be extended as a novel class of antitubercular and antibacterial agents.


Author(s):  
Arif G. Gasanov ◽  
◽  
Ilgar G. Ayyubov ◽  
Gulsum E. Hajiyeva ◽  
Fidan S. Qurbanova ◽  
...  

The results of the research in the field of studying the relationship of the geometric structure of organic compounds with their biological activity are presented. It has been shown that the stereospecific structure of organic and inorganic molecules can have a direct effect on the biologically active properties of substances. Among the known types of stereoisomerism (geometric and optical), this work summarizes the effect of various types of geometric isomerism on the bioactivity of compounds. In addition, the results of the authors’ own research are presented. In particular, the results of studying the antimicrobial and antifungal activity of hydroxyalkyl monoesters of norbornedicarboxylic acid depending on their stereoisomeric forms in relation to various pathogenic microorganisms are shown. The studies were carried out by the serial dilution method. As nutrient media, we used MPA pH 7,2–7,4 for bacteria and Sabouraud’s medium for fungi. The incubation time in a thermostat for bacteria was 18–24 hours at 37ºC, for fungi 1–10 days at 28ºC. It has been noted that the endo-isomers of the synthesized compounds have a higher antimicrobial and antifungal activity against grampositive (Staphylococcus aureus), gramnegative (Escherichia coli, Pseudomonas aeruginosa) bacteria, as well as yeast-like fungi of the genus Candida. Based on the obtained test reports, the synthesized compounds have been recommended for use as local antiseptic preparations.


2021 ◽  
Author(s):  
Gustavo Henrique Andrade Machado ◽  
Marcus Vinícius Cardoso Trento ◽  
Juliana Junqueira Pinelli ◽  
Roberta Hilsdorf Piccoli ◽  
Sérgio Scherrer Thomasi ◽  
...  

Abstract Multicomponent reactions are extremely relevant in green chemistry. They offer better conditions than traditional synthesis and are, therefore, used for many organic modifications. Recently, the synthesis of polyhydroquinolines has received much attention for its high pharmacological potential. In the present study, a polyhydroquinoline derivative was synthesized without the use of catalysts or solvents. The results of nuclear magnetic resonance and infrared spectroscopy demonstrated that the molecule was successfully synthesized. The molecule presents significant results of antimicrobial activity for the bacteria tested in the serial dilution method. It also increased the clotting time by 25.66 seconds for the highest dose and 12.66 seconds for the other doses tested. Prior incubation with the dose of 125 mg reduced the thrombolytic activity to 73%. The 125, 100, and 50 mg doses previously incubated with Bothrops moojeni venom inhibited approximately 30% of the phospholipase activity. The molecule was also able to reduce the cytotoxicity induced by proteases significantly. In conclusion, the molecule presents several biological properties, which highlights its pharmaceutical potential.


2021 ◽  
Vol 20 (1) ◽  
pp. 9-17
Author(s):  
Monica Oktaviana ◽  
Johannes C Prihadi ◽  
Lucky H. Moehario

Introduction: : Practicing hand hygiene is a way to control an infection. The recent COVID-19 pandemic, hand hygiene has become the necessity. Using antiseptic which contain chemical active ingredients causes skin problem. Camellia sinensis is a natural ingredient which its antimicrobial properties is due to the presence of catechin. The study was aimed to determine the effectivity of ethanol extract of Camellia sinensis tea leaves as hand antiseptic. Methods: This research was a comparative experimental analytic to 32 respondents conducted in the Microbiology Laboraroty of Faculty Medicine and Health Sciences–Atma Jaya Jakarta Catholic University of Indonesia. Sampling was carried out by taking bacterial swabs on the right palms. Followed by dilution using serial dilution method and inoculated onto nutrient agar using the spread plate technic. After incubation at 37oC overnight the bacterial colonies were calculated using colony counter within a range of 30-300 colonies per plate. Wilcoxon and Mann-Whitney was used for data analysis. Results: The total number of bacterial colonies after sanitizing using 50% ethanol extract of Camellia sinensis tea leaves was reduced by 55.04% (p=0.003). Meanwhile, 70% alcohol curb the bacterial colonies by 76.84% (p=0.000). The comparison of the effectivity of 50% ethanol extract of Camellia sinensistea leaves versus 70%  alcohol as hand antiseptic was insignificance (p=0.300). Conclusion: 50% ethanol extract of Camellia sinensis tea leaves showed activity against hand’s microorganisms. However, the percentages of Camellia sinensis extract might be increased so as to achieve the effectivity of 70% alcohol.


Author(s):  
M. N. Prikhodko ◽  
Zh. G. Simonova

Research objective. То study the genotypes of Helicobacter pylori and their antibiotic sensitivity in patients with stable angina in combination with chronic gastritis. Material and methods. 46 patients with stable angina with a combination of chronic H. pylori-associated gastritis were included in the open prospective clinical study. To diagnose H. pylori, serological method of detection of antibodies in blood serum was used, PCR - diagnosis of H. pylori genes. Antibiotic sensitivity of H. pylori strains was studied by serial dilution method. Results. In the patients (n = 46) stable angina in combination with chronic gastritis in the endoscopic study by the EGDS method, gastrobioptates were obtained and further investigated. Chronic neatrophic gastritis was diagnosed in 54.3% of patients, atrophic gastritis - in 45.7%. It was found that the genotypes of H. pylori VacA had 8.7% of patients, CagA - 34.7%, HopQ - 13.1%, Oip - 30.4% of patients. Only 13.1% of patients had non-toxic genotypes. The absence of antibiotic resistance of the first line of erication therapy - clarithromycin and amoxicillin - was revealed. 45.7% of patients showed resistance, 39.1% showed weak sensitivity of H. pylori isolates to metronidazole. Conclusions. In patients with stable angina with a combination of chronic gastritis, H. pylori strains with toxigenic genotypes: CagA, Oip, Vac A, HopQ predominate. Resistance of H. pylori isolates to metronidazole was determined in 45.7% of patients.


Author(s):  
Asna Salam ◽  
A.U. Arun ◽  
Shalu Soman

In aquatic environment, one of the most significant manifestations of the toxic stress on aquatic organisms, especially fishes are the over stimulation or depression of respiratory activities. These variations in respiratory activities have been used as in indicator of environmental stress. This study was aimed to assess the sub-lethal toxicity of chlorine through respiratory stress on Oreochromis niloticus. It was noticed that in all dosage experiments as the concentration increased rate of gill movement decreased. The rate of gill movement during the first minute after the dosage in control was 128 per minute. Serial dilution method employed in this study helped to assess the LC50 of chlorine and the value noted was 2 ppm. The minimum number of gill movement noted was in 20ppm dosage and the value was 98 per minute whereas the maximum noted was in 5ppm dosage and the value was 101 per minute. In 60th minutes after dosage also the control showed a value of 126 per minute and 20 ppm dosage showed a very low value such as 32 per minute whereas 5ppm dosage of chlorine showed a reasonably good value of 61 per minute. It was noted that in the case of average gill movement, control showed a very high value such as 127 per minute, whereas 5ppm dosage of chlorine showed a reasonably good value such as 84 per minute, and 20 ppm dosage showed a low value 72 per minute. When a comparison was made between control and differently dosed fishes, it was observed that in all dosed cases the average gill movement was very low when compared with control. A significant difference exists between gill movement in the dosed group and control (P<0.05). Consumption of oxygen increased with an increase in dosage and decreased with increased period of exposure. In control the average oxygen consumption was 0.012 mg/ml/gm body weight, in 5ppm it was 0.014 mg/ml/gm body weight, in 10 ppm it was 0.0155 mg/ml/gm body weight, in 15 ppm it was 0.021 mg/ml/gm body weight and in 20ppm it was0.022 mg/ml/gm body weight.


2021 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Fenny Indriani ◽  
Rike Oktarianti ◽  
Syubbanul Wathon

The ability to taste phenylthiocarbamide (PTC), is autosomal trait inherited in a simple Mendelian recessive pattern. The frequency of Taster and non-Taster allele is varies in different populations. The purpose of the research is to investigate the prevalence, gene frequency and genotype frequency of taster (T) and non taster (ts of Osing population in Kemiren-Banyuwangi. PTC serial dilution method was used to assess the PTC Taster and non-Taster phenotypes. The Hardy–Weinberg method was used to determine allele frequencies. The total of samples were 227 people, male were 117 and female were 110 with age range of 15–30 years were randomly selected. The result showed that the Osing population as Taster were 210 (92,52%) and non Taster were 17samples (7,48%) . The allele frecuency of Taster (T) was 0,73 and non Taster (t) was 0,27 respectively. The genotype frequency of dominant Taster (TT) was 0,54, heterozygosity Taster (Tt) was 0,39, and genotype of non Taster (tt) was 0,07.


Author(s):  
Laxmi Deswal ◽  
Vikas Verma ◽  
Devinder Kumar ◽  
Ashwani Kumar ◽  
Meenakshi Bhatia ◽  
...  

Background: Considering emerging drug resistance in microbes, this work is focused on the synthesis of azole hybrids as novel antimicrobials. Materials & methods: The triazole derivatives were prepared using azide alkyne cycloaddition reaction. The antimicrobial potential of these compounds was evaluated by serial dilution method. Results: A series of azole hybrids containing benzimidazole-1,2,3-triazole skeleton was designed and synthesized via click reaction. Compound 4s showed notable antimicrobial activity against Staphylococcus aureus and Candida albicans (MIC 0.0165 μmol/ml), and 4q gives remarkable radical scavenging activity (IC50 0.0092 μmol/ml). The compounds 4a, 4k, 4o, 4s, 4x. 4m, 4n, 4s, 4t and 4x are commendable antibacterial and antifungal molecules, even better than established drugs. Molecular docking reveals that compound 4s binds with tyrosyl-tRNA synthetase residues through two H-bonds. Conclusion: Compounds 4s and 4k may be considered valuable lead compounds for further optimization as antimicrobial drugs.


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