Microbial biofilm ecology, in silico study of quorum sensing receptor-ligand interactions and biofilm mediated bioremediation.

Biofilms are structured microbial communities of single or multiple populations in which microbial cells adhere to a surface and get embedded in extracellular polymeric substances (EPS). This review attempts to explain biofilm architecture, development phases, and forces that drive bacteria to promote biofilm mode of growth. Bacterial chemical communication, also known as Quorum sensing (QS), which involves the production, detection, and response to small molecules called autoinducers, is highlighted. The review also provides a brief outline of interspecies and intraspecies cell-cell communication. Additionally, we have performed docking studies using Discovery Studio 4.0, which has enabled our understanding of the prominent interactions between autoinducers and their receptors in different bacterial species while also scoring their interaction energies. Receptors, such as LuxN (Phosphoreceiver domain and RecA domain), LuxP, and LuxR, interacted with their ligands (AI-1, AI-2, and AHL) with a CDocker interaction energy of - 31.6083 kcal/mole; - 34.5821 kcal/mole, - 48.2226 kcal/mole and - 41.5885 kcal/mole, respectively. Since biofilms are ideal for the remediation of contaminants due to their high microbial biomass and their potential to immobilize pollutants, this article also provides an overview of biofilm-mediated bioremediation.

Rapid and non-destructive approach for the detection of fried mustard oil adulteration in pure mustard oil via ATR-FTIR spectroscopy-chemometrics.

Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy integrated with chemometrics was effectively applied for the rapid detection and accurate quantification of fried mustard oil (FMO) adulteration in pure mustard oil (PMO). PMO was adulterated with FMO in the range of 0.5-50% v/v. Principal component analysis (PCA) elucidated the studied adulteration using two components with an explained variance of 97%. The linear discriminant analysis (LDA) was adopted to classify the adulterated PMO samples with FMO. LDA model showed 100% accuracy initially, as well as when cross-validated. To enhance the overall quality of models, characteristic spectral regions were optimized, and principal component regression (PCR) and partial least square regression (PLS-R) models were constructed with high accuracy and precision. PLS-R model for the 2nd derivative of the optimized spectral region 1260-1080 cm-1 showed best results for prediction sample sets in terms of high R2 and residual predictive deviation (RPD) value of 0.999 and 31.91 with low root mean square error (RMSE) and relative prediction error (RE %) of 0.53% v/v and 3.37% respectively. Thus, the suggested method can detect up to 0.5% v/v of adulterated FMO in PMO in a short time interval.

Rapid detection and quantification of sucrose adulteration in cow milk using Attenuated total reflectance-Fourier transform infrared spectroscopy coupled with multivariate analysis.

Adulteration of milk to gain economic benefit has become a common practice in recent years. Sucrose is illegally added in milk to reconstitute its compositional requirement by improving the total solid contents. The present study is aimed to use FTIR spectroscopy in combination with multivariate chemometric modelling for the differentiation and quantification of sucrose in cow milk. Pure milk and adulterated milk spectra (0.5-7.5% w/v) were observed in the spectral region 4000-400 cm-1. Principal component analysis (PCA) was used for the discrimination of pure milk and adulterated milk. Soft independent modelling of class analogy (SIMCA) was able to classify test samples with a classification efficiency of 100%. Partial least square regression (PLS-R) and principle component regression (PCR) models were established for normal spectra, 1st derivative and 2nd derivative for the quantification of sucrose in milk. PLS-R model (normal spectra) in the combined wavenumber range of 1070-980 cm-1 showed the best prediction based on parameters like coefficient of determination (R2) (Cal: 0.996; Val: 0.993), RMSE (Cal: 0.15% w/v; Val: 0.20% w/v), RE% (Cal: 4.9% w/v; Val: 5.1% w/v) and RPD (13.40). This method has a detection level of 0.5% w/v sucrose adulteration.

Development of an FTIR based chemometric model for the qualitative and quantitative evaluation of cane sugar as an added sugar adulterant in apple fruit juices.

A Fourier Transform Infrared Spectroscopy based chemometric model was evaluated for the rapid identification and estimation of cane sugar as an added sugar adulterant in apple fruit juices. For all the ninety samples, spectra were acquired in the mid-infrared range (4000 cm-1-400 cm-1). The spectral analysis provided information regarding the distinctive variable region, which lies in the range of 1200cm-1 to 900cm-1, designated as fingerprint region for the carbohydrates. A specific peak in the fingerprint region was observed at 997cm-1 in all the adulterated samples and was undetectable in pure samples. Based on different levels of cane sugar adulteration (5, 10, 15, and 20%), principal component analysis showed the clustering of samples and further helped us in compression of data by selecting wavenumbers with maximum variability based on the loading line plot. Supervised classification methods (SIMCA and LDA) were evaluated based on their classification efficiencies for a test set. Though SIMCA showed 100% classification efficiency (Raw data set), LDA was able to classify the test set with an accuracy of only 96.67% (Raw as well as Transformed data set) between pure and 5% adulterated samples. For the quantitative estimation, calibration models were developed using partial least square regression (PLS-R) and principal component regression method (PCR) methods. PLS-1st derivative showed a maximum coefficient of determination (R2) with a value of 0.991 for calibration and 0.992 for prediction. The RMSECV, RMSEP, LOD and LOQ observed for PLS-1st derivative model were 0.75% w/v, 0.61% w/v, 1.28%w/v and 3.88%w/v, respectively. The coefficient of variation as a measure of precision (repeatability) was also determined for all models, and it ranged from 0.23% to 1.83% (interday), and 0.25% to 1.43% (intraday).

Isolation and characterization of amoxicillin-resistant bacteria and amoxicillin-induced alteration in its protein profiling and RNA yield.

Amoxicillin-resistant bacteria were isolated using selective enrichment procedure. The morphological, biochemical and molecular characterization based on 16S rRNA gene sequencing and phylogenetic analysis of the bacterial strain WA5 confirmed that the strain belongs to the genus Stenotrophomonas. The bacteria were named as Stenotrophomonas sp. strain WA5 (MK110499). Substantial growth was seen in M9 minimal media supplemented with 5 mg L-1 of amoxicillin as a sole source of carbon and energy. RNA yield was also observed to be decreased in the presence of amoxicillin. Amoxicillin (5 mg L-1)-induced alteration is seen on bacterial protein profile and unique polypeptide bands were seen to be induced in the presence of amoxicillin, the bands were subjected to trypsin digestion, and LC-MS/MS analysis showed that the bands belong to the family of DNA-dependent RNA polymerase subunit ß (rpoC). Plasmid DNA isolation indicated the presence of antibiotic-resistant genes being harboured by the plasmid.

Cold survival strategies for bacteria, recent advancement and potential industrial applications.

Microorganisms have evolved themselves to thrive under various extreme environmental conditions such as extremely high or low temperature, alkalinity, and salinity. These microorganisms adapted several metabolic processes to survive and reproduce efficiently under such extreme environments. As the major proportion of earth is covered with the cold environment and is exploited by human beings, these sites are not pristine anymore. Human interventions are a great reason for disturbing the natural biogeochemical cycles in these regions. The survival strategies of these organisms have shown great potential for helping us to restore these pristine sites and the use of isolated cold-adapted enzymes from these organisms has also revolutionized various industrial products. This review gives you the insight of psychrophilic enzyme adaptations and their industrial applications.

Antimicrobial Efficacy of Different Natural Extracts Against Persistent Root Canal Pathogens: An In vitro Study.

INTRODUCTION: The spread of drug-resistant pathogens is one of the most serious threats to successful treatment of microbial diseases. Extracts of plants such as flowers, buds, seeds, leaves, twigs, bark, herbs, wood, fruits, and roots have evoked interest as sources of natural products. Irrigation with a broad-spectrum antiseptic substance and inter-appointment intracanal medication has become a standard regimen in root canal therapy. AIM: The aim of this study is to compare the antimicrobial efficacy of different natural extracts such as guava leaf extract, Aloe vera extract, papaya leaf extract, and cashew apple extract against Enterococcus faecalis and Candida albicans. MATERIALS AND METHODS: The antimicrobial activity was determined using agar diffusion test. The solutions were divided into four groups: Group I - guava leaf extract, Group II - A. vera extract, and Group III - papaya leaf extract, and Group IV - cashew apple extract. The zones of inhibition of growth were recorded. The strains used for this study were E. faecalis ATCC 29212 and C. albicans ATCC 90028. RESULTS AND CONCLUSION: Sodium hypochlorite had demonstrated the best results among the tested solutions. Among the herbal extracts, cashew apple extract and guava leaf extract had shown statistically significant activity against E. faecalis and C. albicans.

Apical Extrusion of Intracanal Bacteria following use of Two Engine-driven Instrumentation Techniques: An in vitro Study.

AIM: The aim of the present study was to compare in vitro the amount of debris extruded apically from extracted teeth, using Twisted files and ProTaper rotary during two different instrumentation systems. MATERIALS AND METHODS: Forty-five human single-rooted mandibular premolar teeth were randomly divided into three groups and contaminated with Enterococcus faecalis. The teeth in experimental groups were instrumented until reaching the working length with ProTaper rotary instruments and Twisted files with XSmart and XSmart Dual groups. Debris extruded from the apical foramen was collected into glass vials and the amount of bacteria was calculated. The data obtained were analyzed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U tests, with p = 0.05 as the level for statistical significance. RESULTS: The XSmart Dual group extruded comparatively lesser bacteria compared to the XSmart group. Lesser amount of bacterial extrusion was seen when Twisted files were used compared to the ProTaper files (p < 0.05). CONCLUSION: Under the circumstances of this in vitro study, it can be concluded that all instrumentation techniques produced measurable apical extrusion of debris. So, it is upon the practitioner to decide which system best fits their individual needs and their level of skill and experience that will provide the best possible endodontic care for our patients. CLINICAL SIGNIFICANCE: The newer instrument designs, including noncutting tips, different cross sections, radial lands, and variable tapers, are better for the clinicians to improve working safety, to reduce the working time, and to create a greater flare within the preparations.

Microabrasion: an effective method for improvement of esthetics in dentistry.

Enamel microabrasion can eliminate enamel irregularities and discoloration defects, thus improving the appearance of teeth. This paper presents the latest treatment protocol of enamel microabrasion to remove stains on the enamel surface. It has been verified that teeth submitted to microabrasion acquire a yellowish colour because of the thinness of the remaining enamel, revealing the colour of dentinal tissue to a greater degree. Enamel microabrasion is a technique that can be used to correct discoloured enamel. Enamel microabrasion was developed in the mid-1980s as a method of eliminating enamel discolouration defects and improving the appearance of teeth. Several years after the method was developed, much has been learned about this technique, long-term results of treatment, and microscopic changes to the enamel surface that have distinguishable clinical implications. In addition, certain patients can benefit from enamel microabrasion to yield attractive cosmetic results. The aim of this study was to report the clinical case of a male patient of 25 years with moderate fluorosis, whose smile was re-established by the use of an enamel microabrasion technique, with 18% hydrochloric acid and pumice slurry shown to be a safe and efficient method for removing fluorosis stains.