Gene expression and molecular characterization of recombinant subtilisin from Bacillus subtilis with antibacterial, antioxidant and anticancer properties

This study investigated the multifunctional attributes such as, antibacterial, antioxidant and anticancer potential of recombinant subtilisin. A codon-optimized subtilisin gene was synthesized from Bacillus subtilis and was successfully transformed into E. coli DH5α cells which was further induced for high level expression in E. coli BL21 (DE3). An affinity purified ~40 kDa recombinant subtilisin was obtained that revealed to be highly alkali-thermostable based on the thermodynamic parameters. The kinetic parameters were deduced that indicated higher affinity of N-Suc-F-A-A-F-pNA substrate towards subtilisin. Recombinant subtilisin demonstrated strong antibacterial activity against several pathogens and showed minimum inhibitory concentration of 0.06 μg/mL against B. licheniformis and also revealed high stability under the influence of several biochemical factors. It also displayed antioxidant potential in a dose dependent manner and exhibited cell cytotoxicity against A549 and MCF-7 cancerous cell lines with IC50 of 5 μM and 12 μM respectively. The identity of recombinant subtilisin was established by MALDI-TOF mass spectrum depicting desired mass peaks and N-terminal sequence as MRSK by MALDI-TOF-MS. The deduced N- terminal amino acid sequence by Edman degradation revealed high sequence similarity with subtilisins from Bacillus strains. The structural and functional analysis of recombinant antibacterial subtilisin was elucidated by Raman, circular dichroism and nuclear magnetic resonance spectroscopy and thermogravimetric analysis. The results contribute to the development of highly efficient subtilisin with enhanced catalytic properties making it a promising candidate for therapeutic applications in healthcare industries.

Correction to "Green-Based Approach to Synthesize Silver Nanoparticles Using the Fungal Endophyte Penicillium oxalicum and Their Antimicrobial, Antioxidant, and In Vitro Anticancer Potential"

[This corrects the article DOI: 10.1021/acsomega.2c05605.].

Green-Based Approach to Synthesize Silver Nanoparticles Using the Fungal Endophyte Penicillium oxalicum and Their Antimicrobial, Antioxidant, and In Vitro Anticancer Potential

A green-based approach for the synthesis of silver nanoparticles has gained tremendous attention in biomedical applications. Fungal endophytes have been recognized as a remarkable biological source for the synthesis of potential nanodrugs. The present study focuses on the fabrication of silver nanoparticles using the fungal endophyte Penicillium oxalicum (POAgNPs) associated with the leaf of the Amoora rohituka plant. Sharp UV-visible spectra at 420 nm appeared due to the surface plasmon resonance of POAgNPs and the reduction of silver salt. FT-IR analysis revealed the presence of functional groups of bioactive compounds of P. oxalicum responsible for the reduction of silver salt and validated the synthesis of POAgNPs. A high degree of crystallinity was revealed through XRD analysis, and microscopy-based characterizations such as AFM, TEM, and FESEM showed uniformly distributed, and spherically shaped nanoparticles. Furthermore, POAgNPs showed a potential inhibitory effect against bacterial and fungal strains of pathogenic nature. POAgNPs also exhibited potential antioxidant activity against the synthetically generated free radicals such as DPPH, superoxide, hydroxyl, and nitric oxide with EC50 values of 9.034 ± 0.449, 56.378 ± 1.137, 34.094 ± 1.944, and 61.219 ± 0.69 μg/mL, respectively. Moreover, POAgNPs exhibited cytotoxic potential against the breast cancer cell lines, MDA-MB-231 and MCF-7 with IC50 values of 20.080 ± 0.761 and 40.038 ± 1.022 μg/mL, respectively. POAgNPs showed anticancer potential through inhibition of wound closure and by altering the nuclear morphology of MDA-MB-231 and MCF-7 cells. Further anticancer activity revealed that POAgNPs induced apoptosis in MDA-MB-231 and MCF-7 cells by differential expression of genes related to apoptosis, tumor suppression, and cell cycle arrest and increased the level of Caspase-3. The novel study showed that P. oxalicum-mediated silver nanoparticles exhibit potential biological activity, which can be exploited as nanodrugs in clinical applications.

Growth Kinetics Monitoring of Gram-Negative Pathogenic Microbes Using Raman Spectroscopy

Optical density based measurements are routinely performed to monitor the growth of microbes. These measurements solely depend upon the number of cells and do not provide any information about the changes in the biochemical milieu or biological status. An objective information about these parameters is essential for evaluation of novel therapies and for maximizing the metabolite production. In the present study, we have applied Raman spectroscopy to monitor growth kinetics of three different pathogenic Gram-negative microbes Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii. Spectral measurements were performed under 532 nm excitation with 5 seconds of exposure time. Spectral features suggest temporal changes in the "peptide" and "nucleic acid" content of cells under different growth stages. Using principal component analysis (PCA), successful discrimination between growth phases was also achieved. Overall, the findings are supportive of the prospective adoption of Raman based approaches for monitoring microbial growth.

Irradiation Induced Biochemical Changes in Human Mandibular Bone: A Raman Spectroscopic Study

Understanding the biochemical changes in irradiated human mandible after radiotherapy of cancer patients is critical for oral rehabilitation. The underlying mechanism for radiation-associated changes in the bone at the molecular level could lead to implant failure and osteoradionecrosis. The study aimed to assess the chemical composition and bone quality in irradiated human mandibular bone using Raman spectroscopy. A total of 33 bone biopsies from 16 control and 17 irradiated patients were included to quantify different biochemical parameters from the Raman spectra. The differences in bone mineral and matrix band intensities between control and irradiated groups were analyzed using unpaired Student's t-test with statistical significance at p < 0.05. Findings suggest that the intensity of the phosphate band is significantly decreased and the carbonate band is significantly increased in the irradiated group. Further, the mineral crystallinity and carbonate to phosphate ratio are increased. The mineral to matrix ratio is decreased in the irradiated group. Principal component analysis (PCA) based on the local radiation dose and biopsy time interval of irradiated samples did not show any specific classification between irradiation sub-groups. Irradiation disrupted the interaction and bonding between the organic matrix and hydroxyapatite minerals affecting the bone biochemical properties. However, the normal clinical appearance of irradiated bone would have been accompanied by underlying biochemical and microscopical changes which might result in radiation-induced delayed complications.

Response of modified microclimates on growth, yield, and incidence of rhizome rot disease of ginger in Assam, India

Field experiments were conducted at Biswanath, Assam, India (26° 42' N and 93° 15' E), during 2016, 2017, and 2018, to evaluate the effect of microclimates on growth, yield, and disease incidence in the ginger crop. The ginger variety Nadia was grown under six microclimates, viz., under shade net for the entire crop season (T1), under shade net from planting to mid-October (T2), with pigeon pea (T3), with maize (T4), with okra (T5), and as a sole crop (T6) in three replicated RBD. Photosynthetically active radiation (PAR), net radiation (Rn), temperature above the ginger canopy, soil temperature, and soil moisture were measured during the critical crop growth period under different microclimates. Recording of rhizome rot disease incidence was done periodically and genomic analysis of pathogen was carried out. PAR recorded above the ginger canopy under T6 was 1688.1 μ mol s-1 m-2, which was attenuated up to 80.1% in other microclimates. The Rn load of the ginger canopy was maximum (446.4 W m-2) under T6, which reduced to below 50 W m-2 under both T3 and T4. Both air temperatures above the ginger canopy and soil temperatures under T3 and T4 were reduced by 3.3 °C and 4.6 °C, respectively, as compared to T6. The pathogen causing the disease in the experimental site was identified as Fusarium oxysporum. Considerable increase in soil and air temperature and soil moisture favored disease incidence (90.3%) under shade net (T1 and T2) treatments, while opposite reason causing significant reduction in disease incidence (16.1%) was observed under T3 and T4. More yield of ginger recorded in treatments T3 (6.21 t ha-1) or T4 (6.48 t ha-1) was attributed to better crop growth and diminutive disease incidence, while the crop was almost damaged due to severe disease incidence under shade net (T1 and T2) treatments.

Species composition of mosquito breeding in bamboo stumps in Sikkim, India

BACKGROUND & OBJECTIVES

Sikkim is a part of Eastern Himalayan biodiversity hotspot of India rich in bamboo flora harbouring over 30 different bamboo species. The present study was aimed to investigate the larval mosquito diversity in the bamboo stumps of Gangtok, Sikkim. Besides, efforts were also made to evaluate the propensity of particular species of mosquito towards specific bamboo species (if any).

METHODS

A total of 75 bamboo stumps of four genera were surveyed and screened at five different sampling sites of Gangtok from July to October 2017. Mosquito species similarity between the five sampling sites and the four varieties of bamboo species was calculated using the Bray-Curtis similarity index.

RESULTS

A total of 216 larvae were collected from 25 different bamboo stumps studied. The species identified were Aedes albopictus, Ae. atlanticus, Ae. aegypti, Orthopodomyia signifera, Oclerotatus japonicus, Oc. taeniorhynchus, Armigeres subalbatus, and Toxorhynchites splendens. The Oc. japonicus (34.5%) was found to be the most abundant species having distribution in Phyllostachys assamica, Dendrocalamus hamiltonii and Bambusa nutans. On the other hand, genus Armigeres subalbatus and Tx. splendens were found to breed only in the stumps of P. assamica. Based on Bray-Curtis similarity index highest species similarity was recorded between D. hamiltonii and P. assamica bamboo species.

INTERPRETATION & CONCLUSION

The study may help to understand the bioecology of the mosquito larvae which may help to devise suitable mosquito control programmes. Future studies including the survey of large number of bamboo stumps both in urban and rural areas of Sikkim may provide better insight into the mosquito diversity in the bamboo stumps of Sikkim.

BACTERIA ASSOCIATED WITH NON-ALCOHOLIC FERMENTED BAMBOO SHOOT FOOD PRODUCT

Pure bacterial cultures were isolated from fermented products collected from two locations of North East India (Assam and Arunachal Pradesh). Forty four variants were identified by 16S rRNA gene sequencing. The dominant microbial genera found were Bacillus, Paenibacillus followed by Oceanobacillus and Lactobacillus in Assam and Bacillus, Enterococcus, Lactobacillus in Arunachal-Pradesh food products. Bacillus isolates showed extracellular enzyme production (amylases, proteases and lipases) as analyzed through plate assay. GC-MS analysis showed beneficial chemical components like organic acids, esters, aminoacids, vitamins in fermented bamboo shoot products. Probiotic attributes of culturable bacterial isolates from bamboo fermentations gives promiscuity for human consumption. Beneficial microorganisms from bamboo shoot fermented food products of North-Eastern region of India were explored and compared using bioinformatics tools.

Development of a novel plant system as biosensor for detecting environmental hazards and bioactive molecules through distinct responses

Currently, chemicals are used excessively in medicine, industry, and agriculture throughout the world. Because of the current rise in environmental pollutants and hazardous exposures of human beings, there is an imperative need for monitoring the environment for biosafety. In addition, the importance of natural products with novel activity for drug or agrochemical scopes is being more and more realized. We report on a novel test system that can act as biosensors for detecting useful compounds while simultaneously monitoring or forecasting the biohazard exposure of organisms to chemicals as well as to physical factors in a given environment. Using different compounds and factors with known biological and cytotoxic activities, a detail plant test procedure has been developed that can be used in detecting and analyzing the value and/or danger of any given compound or treatment, including cell division inhibition, cytotoxicity, growth inhibition, and anticancer activities. The method provides a highly efficient single biosensor system that can replace several individual biotesting procedures. This plant assay procedure is a highly sensitive system for monitoring physical stress factors in the environment, including ionizing and nonionizing radiation. The procedure can be followed throughout the year because of the rapid growth rate of the plant used and its regeneration in ambient conditions. Therefore, the described system is highly useful to thoroughly monitor the environment and detection of new chemicals/compounds.