Biodegradation of low-density polyethylene (LDPE) through application of indigenous strain Alcaligenes faecalis ISJ128.

The resiliency of plastic products against microbial degradation in natural environment often creates devastating changes for humans, plants, and animals on the earth's surface. Biodegradation of plastics using indigenous bacteria may serve as a critical approach to overcome this resulting environmental stress. In the present work, a polyethylene degrading bacterium Alcaligenes faecalis strain ISJ128 (Accession No. MK968769) was isolated from partially degraded polyethylene film buried in the soil at plastic waste disposal site. The biodegradation studies were conducted by employing various methods such as hydrophobicity assessment of the strain ISJ128, measurement of viability and total protein content of bacterial biofilm attached to the polyethylene surface. The proliferation of bacterial cells on polyethylene film, as indicated by high growth response in terms of protein content (85.50 µg mL-1) and viability (1010 CFU mL-1), proposed reasonable suitability of our strain A. faecalis ISJ128 toward polyethylene degradation. The results of biodegradation assay revealed significant degradation (10.40%) of polyethylene film within a short period of time (i.e., 60 days), whereas no signs of degradation were seen in control PE film. A. faecalis strain ISJ128 also demonstrated a removal rate of 0.0018 day-1 along with half-life of 462 days. The scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopy studies not only displayed changes on polyethylene surface but also altered level of intensity of functional groups and an increase in the carbonyl indexes justifying the degradation of polyethylene film due to bacterial activity. In addition, the secondary structure prediction (M fold software) of 16SrDNA proved the stable nature of the bacterial strain, thereby reflecting the profound scope of A. faecalis strain ISJ128 as a potential degrader for the eco-friendly disposal of polyethylene waste. Schematic representation of methodology.

Antibacterial potential of chalcones and its derivatives against Staphylococcus aureus.

Chalcones are natural substances found in the metabolism of several botanical families. Their structure consists of 1,3-diphenyl-2-propen-1-one and they are characterized by having in their chains an α, ß-unsaturated carbonyl system, two phenol rings and a three-carbon chain that unites them. In plants, Chalcones are mainly involved in the biosynthesis of flavonoids and isoflavonoids through the phenylalanine derivation. This group of substances has been shown to be a viable alternative for the investigation of its antibacterial potential, considering the numerous biological activities reported and the increase of the microbial resistance that concern global health agencies. Staphylococcus aureus is a bacterium that has stood out for its ability to adapt and develop resistance to a wide variety of drugs. This literature review aimed to highlight recent advances in the use of Chalcones and derivatives as antibacterial agents against S. aureus, focusing on research articles available on the Science Direct, Pub Med and Scopus data platforms in the period 2015-2021. It was constructed informative tables that provided an overview of which types of Chalcones are being studied more (Natural or Synthetic); its chemical name and main Synthesis Methodology. From the analysis of the data, it was observed that the compounds based on Chalcones have great potential in medicinal chemistry as antibacterial agents and that the molecular skeletons of these compounds as well as their derivatives can be easily obtained through substitutions in the A and B rings of Chalcones, in order to obtain the desired bioactivity. It was verified that Chalcones and derivatives are promising agents for combating the multidrug resistance of S. aureus to drugs. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-022-03398-7.

Antifungal Effect and Inhibition of the Virulence Mechanism of D-Limonene against Candida parapsilosis.

Yeasts from the Candida parapsilosis complex are clinically relevant due to their high virulence and pathogenicity potential, such as adherence to epithelial cells and emission of filamentous structures, as well as their low susceptibility to antifungals. D-limonene, a natural compound, emerges as a promising alternative with previously described antibacterial, antiparasitic, and antifungal activity; however, its mechanisms of action and antivirulence activity against C. parapsilosis complex species have not been elucidated. Therefore, in the present study, we aimed to evaluate the antifungal and antivirulence action, as well as the mechanism of action of D-limonene against isolates from this complex. D-limonene exhibited relevant antifungal activity against C. parapsilosis complex yeasts, as well as excellent antivirulence activity by inhibiting yeast morphogenesis and adherence to the human epithelium. Furthermore, the apoptotic mechanism induced by this compound, which is not induced by oxidative stress, represents an important target for the development of new antifungal drugs.

Revisiting scrub typhus: A neglected tropical disease.

Scrub typhus is an under diagnosed re-emerging vector borne disease caused by an intracellular gram negative bacteria, Orientia. The disease is commonly prevalent in rural and hilly areas of Tsutsugumashi triangle. The diagnosis of the disease is very challenging due to similarity of its early symptoms with other febrile illnesses, like dengue and COVID 19, as well as non-availability of rapid, reliable and cost-effective methods. Moreover, the diverse clinical presentation in severe cases make it significant health problem. The occupational and behavioral risks responsible for the transmission lead to urgent need of vaccine development against the disease. The complete knowledge about its pathogenesis and the interaction with host's immune cells may help the scientists in developing the appropriate diagnostic methods as well as the vaccines.

GC-MS analysis, and evaluation of protective effect of Piper chaba stem bark against paracetamol-induced liver damage in Sprague-Dawley rats: Possible defensive mechanism by targeting CYP2E1 enzyme through in silico study.

The present study attempted to scrutinize the protective effect of the methanolic extract of P. chaba stem bark against paracetamol-induced hepatotoxicity in Sprague-Dawley rats, along with the gas chromatography-mass spectrometry (GC-MS) analysis to identify phytochemicals, which were further docked in the catalytic site of CYP2E1 and the MD simulation for system that plays a major role in the bio-activation of toxic substances that produce reactive metabolites, leading to hepatotoxicity. P. chaba stem methanol extract (250 and 500 mg/kg) were treated orally with the negative control and the negative control silymarin (50 mg/kg) groups. Phytochemical profiling was conducted using GC-MS. In in-silico studies, PyRx software was used for docking analysis and the stability of the binding mode in the target active sites was evaluated through a set of standard MD-simulation protocols using the Charmm 27 force field and Swiss PARAM. Co-administration of P. chaba at both doses with APAP significantly reduced the APAP-augmented liver marker enzymes ALT, AST, ALP, and LDH, along with serum albumin, globulin, hepatic enzymes, histopathological architecture, lipid profiles, total protein, and total bilirubin, and elevated the levels of MDA. The GC-MS analysis indicated that P. chaba extract is enriched in fatty acid methyl esters (46.23 %) and alkaloids (10.91 %) and piperine is represented as a main phytochemical. Among all the identified phytochemicals, piperine (-8.0 kcal/mol) was found to be more interacting and stable with the binding site of CYP2E1. Therefore, all of our findings may conclude that the P. chaba stem extract and its main compound, piperine, are able to neutralize APAP-induced hepatic damage.

Chemical Composition and Antimicrobial Potential of Essential Oil of Acritopappus confertus (Gardner) R.M.King & H.Rob. (Asteraceae).

Microbial resistance has become a worrying problem in recent decades after the abusive use of antibiotics causing the selection of resistant microorganisms. In order to circumvent such resistance, researchers have invested efforts in the search for promising natural substances, such as essential oils. Thus, the objective of this work was to determine the chemical composition of the essential oil of Acritopappus confertus leaves, to evaluate its intrinsic effect and its effects in combination with drugs against pathogenic fungi and bacteria, in addition to verifying the inhibition of virulence in Candida strains. To this end, the oil was verified by gas chromatography coupled with mass spectrometry (GC/MS). Candida strains were used for antifungal assays by means of the serial microdilution technique, in order to determine the average inhibitory concentration (IC50), and for the modification assays, sub-inhibitory concentrations (MIC/8) were used. Finally, the natural product's ability to inhibit the formation of filamentous structures was evaluated. In antibacterial tests, the MIC of the oil against strains of Staphylococcus aureus and Escherichia coli and its modifying effects in association with gentamicin, erythromycin, and norfloxacin were determined. The major constituent of the essential oil was the monoterpene myrcene (54.71%). The results show that the essential oil has an antifungal effect, with C. albicans strains being the most susceptible. Furthermore, the oil can potentiate the effect of fluconazole against strains of C. tropicalis and C. albicans. Regarding its effect on micromorphology, the oil was also able to inhibit the filaments in all strains. In combination with antibiotics, the oil potentiated the drug's action by reducing the MIC against E. coli and S. aureus. It can be concluded that the essential oil of A. confertus has potential against pathogenic fungi and bacteria, making it a target for the development of an antimicrobial drug.

Bioactive Natural Products for Chemical Control of Microorganisms: Scientific Prospecting (2001-2021) and Systematic Review.

The inappropriate use of synthetic antibiotics has become a global public health problem. Therefore, the study of new alternatives for the treatment of infectious diseases is relevant and natural bioactive products are on the rise. This study conducted a scientific prospection of bioactive natural products with promising applications in the chemical control of microorganisms. A systematic review of the most recent articles was performed according to the following three steps: (i) eligibility assessment, (ii) screening, and (iii) inclusion of articles and information extraction. There has been an increase in the number of scientific publications on bioactive natural products for microbial control in the CAPES and SciELO databases (2001-2021). Seventeen relevant articles were included, most of which focused on extracts. Ascorbic acid, chlorogenic acid, chrysin, and quercetin were the most cited compounds. Natural products were shown to be effective in inhibiting more than 30 microorganisms. A discussion was presented on the research trends.