Effect of Glucose on Endo-xylanase and β-xylosidase Production by Fungi Isolated in Indonesia

Xylanases are widely produced by fungi, and the production of polysaccharide-degrading enzymes, in general, are usually subjected to carbon catabolite repression. In this work, the ability of several Indonesian indigenous fungi to produce endo-xylanase and β-xylosidase and their responses to glucose as a repressor were determined. Ten fungi were grown in a liquid medium supplemented with glucose as the repressor (0, 1%, 3%, and 5%), and the endo-xylanase and β-xylosidase productions were assayed. Aspergillus aculeatus FIG1 and A. oryzae KKB4 produced 3.85 and 0.70 U/mL of endo-xylanase, respectively, compared with other strains (0.22 U/mL or less). Trichoderma asperellum PK1J2, T. virens MLT2J2, A. aculeatus FIG1, T. asperellum MLT5J1, A. oryzae KKB4, and T. asperellum MLT3J2 produced 0.021–0.065 U/mL of β-xylosidase, whereas the other strains produced 0.013 U/mL or less of β-xylosidase. Adding 1% glucose to the growth medium can partially repress endo-xylanase production in A. aculeatus FIG1, T. asperellum PK1J2, and T. virens MLT4J1 and completely repress other strains. By adding 1% glucose, strains FIG1, PK1J2, and MLT4J1 suffered almost complete repression of β-xylosidase production, although such strains exhibited partial repression of endo-xylanase production. β-Xylosidase produced by the other strains showed complete repression by adding 1% glucose, except for A. aculeatus FIG1, A. tamarii FNCC 6151, and T. asperellum MLT1J1, which showed partial repression. Therefore, adding 3% glucose to the growth medium can result in complete repression of endo-xylanase and β-xylosidase productions in all strains examined.

Anticancer and Antimicrobial Activity of Red Sea Seaweeds Extracts-Mediated Gold Nanoparticles

Biosynthesis of gold nanoparticles (AuNPs) is emerging as a better alternative to traditional chemical-based techniques. During this study, extracts of different marine algae species Ulva rigida (green algae), Cystoseira myrica (brown Algae), and Gracilaria foliifera (red Algae) were utilized as reducing and capping agents to synthesize AuNPs. AuNPs capped by U. rigida, C. myrica, and G. foliifera were confirmed by the appearance of surface plasmonic bands at 528, 540, and 543 nm, respectively. Transmission electron microscopy revealed mostly spherical shapes of AuNPs having a size of about 9 nm, 11 nm, and 13 nm for C. myrica, and G. foliifera extracts, respectively. Fourier transform-infrared spectroscopy (FTIR) illustrated the major chemical constituents of U. rigida, C. myrica, and G. foliifera. LC50 values of the biosynthesized AuNPs against Artemia salina nauplii were calculated at a range of concentrations (5-188 μg ml−1) after 16 to 24h. AuNPs concentration-dependent lethality was noted and U. rigida extracts-mediated AuNPs presented the lowest cytotoxicity. The biosynthesized AuNPs exhibited significant anticancer activity (86.83%) against MCF-7 cell lines (human breast adenocarcinoma cell lines) at 188 µg/ml concentration. G. foliifera demonstrated the highest anticancer value (92.13%) followed by C. myrica (89.82%), and U. rigida (86.83%), respectively. The AuNPs synthesized by different algal extracts showed variable antimicrobial activity against the tested pathogenic microorganisms. AuNPs of U. rigida extracts showed significant antimicrobial activity against dermatophytic fungi Trichosporon cataneum (30 mm) followed by Trichophyton mantigrophytes (25 mm). Furthermore, it also exhibited mild activity against Escherichia coli (17 mm), Cryptococcus neoformans (15 mm), Candida albicans (13 mm), and Staphylococcus aureus (11mm), respectively whereas no effects were observed against Bacillus cereus. To conclude, AuNPs can be effectively synthesized by marine algal species, and particularly U. rigida extracts could be effective reducing agents for the green AuNPs synthesis. These AuNPs could potentially serve as efficient alternative anticancer agents against human breast adenocarcinoma and anti-dermatophytes associated with skin infections.

Effect of Brine fermented Pickling to Physicochemical, Anti-nutritional, and Microbiological Attributes of Pickled gboma Eggplant (Solanum macrocarpon)

Gboma eggplant (Solanum macrocarpon) has low calorie, high phenolic and antioxidant, excellent dietary fibre and mineral content. Besides healthy effects, gboma eggplant also contained numerous anti-nutrients unbeneficial for human health. Due to high moisture content, gboma eggplant was highly perishable during post-harvest. This research observed the changes of nutritional proximate, mineral contents, acidification indexes, anti-nutrients, phytochemical and antioxidant properties, texture profiles, microbiological characteristics of both raw and pickled gboma eggplant. Gboma eggplant fruits were soaked in clean water for 2 minutes before cutting their calyx lobes. The pre-treated fruits were submerged in sterilized brine (5% salt) for 8 days. Periodically, pickled samples were taken to examine physicochemical, anti-nutritional, and microbiological attributes of pickled gboma eggplant. Results showed that nutritional proximate of moisture, ash, protein, fat, fibre, carbohydrate was varied slightly during fermentation. There was a decreasing trend of moisture and carbohydrate; meanwhile, there was an increasing trend of ash, protein, fibre during 8 days of fermentation. There was no significant difference of fat during pickling. There was a minor increment of mineral contents in all samples. There was accumulation of phenyllactic acid, ascorbic acid content and titratable acidity with exception of pH. Anti-nutrient contents like tannin, phytate, oxalate, steroidal glycoalkaloid greatly decreased in raw and pickled eggplant. Remarkable increments of total phenolic, flavonoid, DPPH free radical scavenging and FRAP ferric reducing antioxidant of raw and pickled eggplant was presented. Texture profiles of hardness, crispness, fracturability, crunchiness revealed a minor reduction of sensory scores during 8 days of fermentation. Lactic acid bacteria, Bacillus significantly proliferated; meanwhile, Micrococcus and S. aureus were absolutely retarded in pickled eggplant. Yeast and fungi increased in the first 4 days and decreased afterwards. There was no significant difference of proximate compositions; mineral contents; phenyllactic acid, ascorbic acid content, pH and titratable acidity; anti-nutritional contents; phytochemical and antioxidant properties; texture profile (sensory score); microbiological load (with exception of S. aureus) between pickled gloma eggplants at day 6th and day 8th of fermentation. At a quick glance, the length of fermentation could be shorted to 6 days instead of 8 days. However, at the 6th day, S. aureus load was still presented at 0.33±0.01 log CFU/g. The fermentation should be lasted to 8th day so that S. aureus load could be dropped down to zero to ensure microbial food safety. Raw gboma eggplant should be fermented in 8% brine solution for 8 days to obtain the best physicochemical, anti-nutritional, and microbiological properties of pickle. Findings of this research suggested that fermentation pickling would be an appropriate approach to improve nutritional, physicochemical and functional criteria while controlling toxic chemical residues, retarding the growth and proliferation of spoilage and pathogen microorganisms.

Modulation in Plant Growth and Drought Tolerance of Wheat Crop upon Inoculation of Drought-tolerant-Bacillus Species Isolated from Hot Arid Soil of India

Drought is one of the most detrimental environmental stressors to plants with the potential to decrease crop yields and affect agricultural sustainability. Native bacteria with beneficial traits enhance plant growth and help avoid and reverse the effects of drought in plants to a greater extent. In the present study, we aimed to ( i ) isolate drought-tolerant Bacillus isolates from the rhizosphere soil of wheat crop grown at different locations in Jaisalmer district, Rajasthan state and (ii) further evaluate their ability to enhance plant growth and induce drought tolerance in wheat ( Var. HD-2967) grown under drought stress conditions. Of more than 100 isolates, two putative Bacillus isolates capable of tolerating 30 % polyethylene glycol-6000 (PEG-6000) [equivalent to -9.80 MPa (Megapascal)] were identified as Bacillus altitudinis DT-89 and Bacillus paramycoides DT-113. These isolates exhibited different plant growth promoting (PGP) attributes such as phosphate solubilization, and production of siderophore, exopolysaccharide, ammonia, indole acetic acid and cytokinin at low osmotic stress of 10% PEG-6000 but shown variable response at higher osmotic stress particularly at 30% PEG-6000. However, they did not show any antifungal activity and one isolate was negative for phosphate solubilization. Of two strains, B. altitudinis DT-89 function more prominently with respect to plant growth promotion and drought tolerance to plant in the early stage but protective traits of B. paramycoides DT-113 was more prominent after 75 days as evident by increased EPS (164%), root dry weight (144.44%), chlorophyll content (90.26%), SOD (389%) and proline (99.3%). The results support both the strains as a potential candidate to alleviate drought stress and enhance plant growth in the drought regions.

Culturable Bacterial Isolates from Arctic Soil shows High Biotechnological Potential

Polar microbiology remains as the most fascinating area of research which mainly focuses on exploration of psychrophilic organisms for having their cold-active enzymes of biotechnological potential. In this study, we have explored a culturable bacterial community and isolated 27 bacterial isolates with a different morphology from an unexplored site of Arctic region, for the possibility of identifying various active biomolecules. Screening of various isolates in a culture dependent manner helped us to identify strains capable of producing extracellular enzymes. The optimal growth parameters of most of the isolates are ranges between 18-22°C temperature, 3-5 days of incubation, 6-9 pH, and 3-5% (w/v) NaCl in LB media. It has also been found that among these isolates, 63% are able to produce lipase, 17% amylase, 7% xylanase and 7% isolates have responded for phosphatase activity but there are no isolates found for gelatinase and cellulase production ability. In addition, few isolates can also produce secretory protease, urease, β-galactosidase, etc. 16SrRNA gene sequence-based phylogeny revealed that the isolates belong to the genera of Psychrobacter, Planococcus, Halomonas, Arthrobacter, Oceanisphaera, Marinbacter, Pseudomonas, Algoriphagus. Strikingly, none of the Arctic isolates showed resistance towards commonly used antibiotics which indicates that the unexplored habitat is devoid of antibiotic exposure and so does the rise of antimicrobial resistance. The structure-function relationship of the isolated bioactive compounds from these isolates are the major focus of future research.

Corona Discharge Power of Plasma Treatment Influence on the Physicochemical and Microbial Quality of Enoki Mushroom (Flammulina velutipes)

Plasma treatment was widely known as an effective technology applied for contact-surface decontamination. Enoki (Flammulina velutipes) was an edible-medicinal mushroom with different phytochemicals and bioactive components beneficial for human health. Enoki mushroom had high respiration rate therefore it was highly perishable after harvesting. Moreover, it was greatly susceptible to microbial contamination but it was not feasible to be decontaminated by normal water washing. It’s urgent to extend shelf-life and control microbial criteria on this mushroom in dry manner without aqueous treatment. Corona discharge plasma was among 4 kinds of diverse cold atmospheric pressure plasma sources widely applied in food industry. This study demonstrated the influence of corona discharge plasma power values (control, 120, 150, 180, 210 W) on the physicochemical and microbial characteristics of Enoki mushroom during 10 days of storage at ambient temperature. Results showed that Enoki mushroom should be treated at 150 W of corona discharge plasma power to retain weight loss, total soluble solid, vitamin C in acceptable values while reducing total Aerobic count, Coliform, Enterobacteriaceae as much as possible. At the 10th day of storage, the weight loss, total soluble solid, vitamin C, total Aerobic count, Coliform, Enterobacteriaceae were recorded at 3.35±0.07%, 6.98±0.03 oBrix, 14.81±0.04 mg/100 g, 4.71±0.05 log CFU/g, 3.17±0.02 log CFU/g, 2.13±0.01 CFU/g, respectively. Findings of this research proved that corona discharge plasma pretreatment would be appropriate to maintain physicochemical properties and retard microbial loads on Enoki mushroom during preservation.

Detection of IgG and IgM Levels in Patients with COVID-19 in Mosul Province, Iraq

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) has become the most dangerous viral infection worldwide. Since its identification in late 2019, the number of medical trials to combat the infection has sharply increased. Here, we investigated the profiles of IgG and IgM in 85 patients with confirmed SARS-CoV-2 infection from day 1 after symptom onset until day 35 with 5-day intervals. Serum samples were collected and stored until use. We observed that IgM levels were detectable on day 5 post symptom onset and increased sharply, with the highest rate detected in moderate cases (32.332 ± 4.32, n=10). Subsequently, a significant reduction in IgM was observed until it was undetectable on day 35 after symptom onset. Meanwhile, IgG levels were detected on day 10 post symptom onset, and the highest rate was observed in moderate cases (8.232 ± 2.3, n=10). A significant increase in IgG rate was observed in all patients, with the highest rate in moderate cases (42.432 ± 4.34, n=67) on day 35 post symptom onset. The statistical difference between the case and control groups was significant (p≤0.001). Two out of 85 patients died during the study.

Efflux-Mediated bile Resistance in Gram-Positive Pathogens

Gram-positive pathogens are causing many serious infections that affect humans and result in mild to severe diseases worldwide. In order to survive and initiate infection, enteric pathogens must resist the physiochemical defence factors in the human intestinal tract. One of these defence factors is bile, a potent antibacterial like compound in the intestine. Efflux pumps are the important mechanism by which bacteria resist antibacterial agents such as bile. Efflux of antimicrobial substances outside the bacterial cell is considered as a key factor for intestinal colonization and virulence of enteric pathogens. This paper will review the research conducted on efflux–mediated bile resistance in Staphylococcus aureus, Listeria monocytogenes, Enterococcus faecalis and Clostridium perfringens. These bacteria colonize in the human & animal gastrointestinal tract and they have a multiple mechanism to resist the innate defences in the gut and antibacterial activity of bile. However, bile resistance in these bacteria is not fully understood. The evidence from this review suggests that Gram-positive pathogens have the ability to active transport of bile. Further research is needed to know how these pathogens sense bile and how bile regulates its virulence factor. In general, therefore, it seems that understanding the specific mechanism of bile resistance in enteric bacteria including gram-positive pathogens may involve in the development of novel strategies to control and treatment of gastrointestinal infections.

Effect of Lemongrass Essential Oil based Mouthwash against Microflora Associated with Dental Plaque

Mouthwash is one of the most convenient and effective method employed for dental plaque management. The aim of the undertaken study was to establish the antimicrobial and anti-biofilm properties of lemongrass essential oil (LGEO) based mouthwash on microbial flora from dental plaque and also check cytotoxicity of mouthwash formulation. Five main colonizers of dental plaque representing dental microflora and three different bacterial species mainly responsible for the formation of biofilm were selected in this study. LGEO based mouthwash was developed and its stability was also determined. The antimicrobial and anti-biofilm activity of LGEO based mouthwash has been evaluated against the representative dental microflora as per CLSI guidelines. Cytotoxicity of mouthwash was checked by globally used MTT assay employing NIH 3T3 mouse fibroblast cell line. The mouthwash has been found to exhibit the stability in its major component, citral and also found exhibit antimicrobial and anti-biofilm activity against dental microflora. No cytotoxic effect was observed on mouse fibroblast cell line. LGEO in formulated mouthwash being a natural, herbal material isolated from traditional medicinal plants appears as a good and effective substitute to control the microflora linked with dental plaque.

Clinical, Epidemiological and Microbiological Profile of A Potentially Pathogenic Environmental Saprophyte, Burkholderia pseudomallei; at A Tertiary Care Hospital in Coastal India

Melioidosis is a severe systemic infectious disease caused by Burkholderia pseudomallei, a gram-negative bacillus with bipolar staining. It is an environmental saprophyte endemic to Southeast Asia and Northern Australia. The disease can have varying manifestations. This is a retrospective study of the clinical and microbiological profile of culture-proven cases of melioidosis who presented to a tertiary care hospital in Coastal Karnataka between January 2018 and December 2020. The epidemiological, demographic, clinical and laboratory characteristics were studied and analyzed. A total of 27 cases were seen during the study period. All patients were from the western coastal areas of India. Fever was the most common presenting complaint. Analysis of the clinical manifestations showed 11 (40.74%) with bacteremia. Pneumonia was the most common primary clinical presentation with 11 cases (40.74%). 9 (33.3%) patients had an abscess in some part of the body on presentation. Secondary foci were seen in 5 (18.5%) patients. The prominent risk factors seen were history of type 2 diabetes mellitus, age >40 years, alcoholism and smoking. 13 (48.15%) were started with the treatment regimen for melioidosis. Only 8 (29.63%) were prescribed the eradication treatment regimen. One case which was inadequately treated came back with reactivation of melioidosis. Varied clinical presentation of melioidosis makes the specific clinical diagnosis difficult. Due to the high mortality and morbidity rate, early diagnosis and prompt management is warranted, this requires clinical vigilance and an intensive microbiological workup. Lack of adherence to the treatment protocol can lead to reactivation.