Tracking the Variations in Trace Elements, Some Nutrients, Phenolics, and Anthocyanins in Grewia asiatica L. (Phalsa) at Different Fruit Development Stages

Grewia asiatica L. (phalsa) is a very prevalent berry in Pakistan and is consumed extensively as raw or in the form of juice. Here, for the first time, we assessed phalsa from Pakistan in terms of variations in macro and micro minerals, nutrients, and bio-active phyto-constituents including total phenolic and anthocyanin contents at different fruit developmental stages. It was found that the sugars in phalsa increased from D1 (small at the initial fruit setting stage) to D6 development stage (fully ripened fruit) where sugars at D5 (near to fully ripe) and D6 stages were many times greater than at D1, D2 (unripe close to full-size completion), D3 (close to semi ripe), and D4 stage (semi ripened and full-size attainment). Total acidity of was declined in all developmental stages, where the D1 stage displayed maximum and D6 with the lowest acidity. Ascorbic acid was decreased from D1 to D2 and then increased gradually from D3 to D5 stages. At the D6 stage, again a steep decline in ascorbic acid was observed. The total phenolics (mg gallic acid equivalents/100g) at stage D6 were higher (136.02 ± 1.17), whereas D1 being the lowermost in total phenolic content (79.89 ± 1.72). For anthocyanins (mg/100g), an increasing pattern of changes was observed in all stages of phalsa fruit where the D1 stage showed lower (13.97 ± 4.84) anthocyanin contents which then increased gradually at stage D2 (67.79 ± 6.73), but increased sharply at D3 (199.66 ± 4.90), D4 (211.02 ± 18.85), D5 (328.41 ±14.96) and D6 (532.30 ± 8.51) stages. A total of four anthocyanins such as cyanidin, delphidine-3-glucoside, pelargonidin, and malvidin in phalsa were identified using HPLC procedures, and a significant > 90 % DPPH inhibition in phalsa was observed at the D5 and D6 development stages. The macro and micro minerals including Ni, Zn, Fe, Ca, Cu, Mg, Na, P, and K contents were decreased from initial (D1) stage to the final (D6) development stage, while only Fe displayed an increasing trend from the initial to final fruit development stages (D1-D6). Conclusively, these findings could be of great interest for patients who are intended to consume phalsa as adjuvant therapy against diabetes and metabolic syndromes and other diseases involving reactive oxygen species with minimum metal toxicity.

Microorganism-mediated biodegradation for effective management and/or removal of micro-plastics from the environment: a comprehensive review

Micro- plastics (MPs) pose significant global threats, requiring an environment-friendly mode of decomposition. Microbial-mediated biodegradation and biodeterioration of micro-plastics (MPs) have been widely known for their cost-effectiveness, and environment-friendly techniques for removing MPs. MPs resistance to various biocidal microbes has also been reported by various studies. The biocidal resistance degree of biodegradability and/or microbiological susceptibility of MPs can be determined by defacement, structural deformation, erosion, degree of plasticizer degradation, metabolization, and/or solubilization of MPs. The degradation of microplastics involves microbial organisms like bacteria, mold, yeast, algae, and associated enzymes. Analytical and microbiological techniques monitor microplastic biodegradation, but no microbial organism can eliminate microplastics. MPs can pose environmental risks to aquatic and human life. Micro-plastic biodegradation involves fragmentation, assimilation, and mineralization, influenced by abiotic and biotic factors. Environmental factors and pre-treatment agents can naturally degrade large polymers or induce bio-fragmentation, which may impact their efficiency. A clear understanding of MPs pollution and the microbial degradation process is crucial for mitigating its effects. The study aimed to identify deteriogenic microorganism species that contribute to the biodegradation of micro-plastics (MPs). This knowledge is crucial for designing novel biodeterioration and biodegradation formulations, both lab-scale and industrial, that exhibit MPs-cidal actions, potentially predicting MPs-free aquatic and atmospheric environments. The study emphasizes the urgent need for global cooperation, research advancements, and public involvement to reduce micro-plastic contamination through policy proposals and improved waste management practices.

Microbial production of docosahexaenoic acid (DHA): biosynthetic pathways, physical parameter optimization, and health benefits

Omega-3 fatty acids, including docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and α-linolenic acid (ALA), are essential polyunsaturated fatty acids with diverse health benefits. The limited conversion of dietary DHA necessitates its consumption as food supplements. Omega-3 fatty acids possess anti-arrhythmic and anti-inflammatory capabilities, contributing to cardiovascular health. Additionally, DHA consumption is linked to improved vision, brain, and memory development. Furthermore, omega-3 fatty acids offer protection against various health conditions, such as celiac disease, Alzheimer's, hypertension, thrombosis, heart diseases, depression, diabetes, and certain cancers. Fish oil from pelagic cold-water fish remains the primary source of omega-3 fatty acids, but the global population burden creates a demand-supply gap. Thus, researchers have explored alternative sources, including microbial systems, for omega-3 production. Microbial sources, particularly oleaginous actinomycetes, microalgae like Nannochloropsis and among microbial systems, Thraustochytrids stand out as they can store up to 50% of their dry weight in lipids. The microbial production of omega-3 fatty acids is a potential solution to meet the global demand, as these microorganisms can utilize various carbon sources, including organic waste. The biosynthesis of omega-3 fatty acids involves both aerobic and anaerobic pathways, with bacterial polyketide and PKS-like PUFA synthase as essential enzymatic complexes. Optimization of physicochemical parameters, such as carbon and nitrogen sources, pH, temperature, and salinity, plays a crucial role in maximizing DHA production in microbial systems. Overall, microbial sources hold significant promise in meeting the global demand for omega-3 fatty acids, offering an efficient and sustainable solution for enhancing human health.

Telehealth Policy, Practice, and Education: a Position Statement of the Society of General Internal Medicine

Telehealth services, specifically telemedicine audio-video and audio-only patient encounters, expanded dramatically during the COVID-19 pandemic through temporary waivers and flexibilities tied to the public health emergency. Early studies demonstrate significant potential to advance the quintuple aim (patient experience, health outcomes, cost, clinician well-being, and equity). Supported well, telemedicine can particularly improve patient satisfaction, health outcomes, and equity. Implemented poorly, telemedicine can facilitate unsafe care, worsen disparities, and waste resources. Without further action from lawmakers and agencies, payment will end for many telemedicine services currently used by millions of Americans at the end of 2024. Policymakers, health systems, clinicians, and educators must decide how to support, implement, and sustain telemedicine, and long-term studies and clinical practice guidelines are emerging to provide direction. In this position statement, we use clinical vignettes to review relevant literature and highlight where key actions are needed. These include areas where telemedicine must be expanded (e.g., to support chronic disease management) and where guidelines are needed (e.g., to prevent inequitable offering of telemedicine services and prevent unsafe or low-value care). We provide policy, clinical practice, and education recommendations for telemedicine on behalf of the Society of General Internal Medicine. Policy recommendations include ending geographic and site restrictions, expanding the definition of telemedicine to include audio-only services, establishing appropriate telemedicine service codes, and expanding broadband access to all Americans. Clinical practice recommendations include ensuring appropriate telemedicine use (for limited acute care situations or in conjunction with in-person services to extend longitudinal care relationships), that the choice of modality be done through patient-clinician shared decision-making, and that health systems design telemedicine services through community partnerships to ensure equitable implementation. Education recommendations include developing telemedicine-specific educational strategies for trainees that align with accreditation body competencies and providing educators with protected time and faculty development resources.

N-Arylacetamide derivatives of methyl 1,2-benzothiazine-3-carboxylate as potential drug candidates for urease inhibition

Urease enzyme is an infectious factor that provokes the growth and colonization of virulence pathogenic bacteria in humans. To overcome the deleterious effects of bacterial infections, inhibition of urease enzyme is one of the promising approaches. The current study is designed to synthesize new 1,2-benzothiazine-N-arylacetamide derivatives 5(a-n) that can effectively provide a new drug candidate to avoid bacterial infections by urease inhibition. After structural elucidation by FT-IR, proton and carbon-13 NMR and mass spectroscopy, the synthesized compounds 5(a-n) were investigated to evaluate their inhibitory potential against urease enzyme. In vitro analysis against positive control of thiourea indicated that all the synthesized compounds have strong inhibitory strengths as compared to the reference drug. Compound 5k, being the most potent inhibitor, strongly inhibited the urease enzymes and revealed an IC₅₀ value of 9.8 ± 0.023 µM when compared with the IC₅₀ of thiourea (22.3 ± 0.031 µM)-a far more robust inhibitory potential. Docking studies of 5k within the urease active site revealed various significant interactions such as H-bond, π-alkyl with amino acid residues like Val744, Lys716, Ala16, Glu7452, Ala37 and Asp730.

Biobutanol production from sustainable biomass process of anaerobic ABE fermentation for industrial applications

The growing population increases the need to develop advanced biological methods for utilizing renewable and sustainable resources to produce environmentally friendly biofuels. Currently, energy resources are limited for global demand and are constantly depleting and creating environmental problems. Some higher chain alcohols, like butanol and ethanol, processing similar properties to gasoline, can be alternate sources of biofuel. However, the industrial production of these alcohols remains challenging because they cannot be efficiently produced by microbes naturally. Therefore, butanol is the most interesting biofuel candidate with a higher octane number produced naturally by microbes through Acetone-Butanol-Ethanol fermentation. Feedstock selection as the substrate is the most crucial step in biobutanol production. Lignocellulosic biomass has been widely used to produce cellulosic biobutanol using agricultural wastes and residue. Specific necessary pretreatments, fermentation strategies, bioreactor designing and kinetics, and modeling can also enhance the efficient production of biobutanol. The recent genetic engineering approaches of gene knock in, knock out, and overexpression to manipulate pathways can increase the production of biobutanol in a user friendly host organism. So far various genetic manipulation techniques like antisense RNA, TargeTron Technology and CRISPR have been used to target Clostridium acetobutylicum for biobutanol production. This review summarizes the recent research and development for the efficient production of biobutanol in various aspects.

Effect of Chilled Storage on Antioxidant Capacities and Volatile Flavors of Synbiotic Yogurt Made with Probiotic Yeast Saccharomyces boulardii CNCM I-745 in Combination with Inulin

Fermentation of available sugars in milk by yogurt starter culture initially and later by Saccharomyces boulardii (Probiotic yeast) improves the bioavailability of nutrients and produces bioactive substances and volatile compounds that enhance consumer acceptability. The combination of S. boulardii, a unique species of probiotic yeast, and inulin, an exopolysaccharide used as a prebiotic, showed remarkable probiotic and hydrocolloid properties in dairy products. The present study was designed to study the effect of fermentation and storage on antioxidant and volatile capacities of probiotic and synbiotic yogurt by incorporation of S. boulardii and inulin at 1%, 1.5%, and 2% (w/v), compared with the probiotic and control plain yogurt. All samples were stored at 4 °C, and during these four weeks, they were analyzed in terms of their antioxidant and volatile compounds. The synbiotic yogurt samples having inulin and S. boulardii displayed significantly higher DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical activity values and more values of TPC (total phenol contents) than control plain yogurt. A total of 16 volatile compounds were identified in S5-syn2 and S4-syn1.5, while S3-syn1 and S2-P had 14, compared with the control S1-C plain yogurt samples, which had only 6. The number of volatile compounds increased with the increasing concentration of inulin throughout the storage period. Therefore, this novel synbiotic yogurt with higher antioxidant and volatile compounds, even with chilling storage conditions, will be a good choice for consumer acceptability.

Mitigating Ammonia and Greenhouse Gaseous Emission From Arable Land by Co-application of Zeolite and Biochar

The intensive use of chemical fertilizers in arable farming dramatically increased environmental pollution through anthropogenic ammonia (NH₃) and greenhouse gaseous emissions. Therefore, there is a need to develop improved fertilizer management practices that can reduce these losses. An experiment was conducted to assess the mitigating effects of sole or combined application of zeolite with biochar on gaseous emissions from arable land. For this purpose, zeolite (clinoptilolite) was mixed with different doses of biochar (produced from Dalbergia Sissoo wood chips) and applied along with the recommended dose of chemical fertilizer (NPK @ 150, 100, and 60 kg ha^-1, respectively) on arable land in years 2013-14 and 2014-15. Immediately after application, these were incorporated into the top 10 cm of the soil layer and wheat was sown. Treatments were as follows: C = control, Z = zeolite @ 5 t ha^-1, B1Z = biochar @ 3 t ha^-1 + zeolite @ 5 t ha^-1, B2Z = biochar @ 6 t ha^-1 + zeolite @ 5 t ha^-1, and B3Z = biochar @ 9 t ha^-1 + zeolite @ 5 t ha^-1. The experiment was laid out in a randomized complete block design (RCBD) with three replicates. The experimental plot size was 6 m × 4 m. Randomly, ten soil samples from each plot were taken at a depth of 0-15 cm and mixed to get a composite sample. All the samples were immediately stored in a freezer at -18°C until gaseous analysis in order to prevent N transformations. Each soil sample was analyzed for emission of NH₃, CO₂, and CH₄ by using a selected-ion flow-tube mass spectrometer (SIFT-MS). Co-application of zeolite and biochar reduced NH₃ and CH₄ emissions by an average of 87 and 58% compared to the control, respectively. However, CO₂ emission was increased by 104% relative to the control. The NH₃ emission was decreased by an average of 61, 78, 90, and 92% by Z, B1Z, B2Z, and B3Z treatments compared to the control. Similarly, the decrement in CH₄ emission was 47, 54, 55, and 65%. In contrast, the increment in CO₂ emission was 42, 110, and 160% for B1Z, B2Z, and B3Z, respectively, while interestingly, a reduction of 12% was observed in Z treatment. Besides, co-application of zeolite and biochar at the highest dose (B3Z) improved soil chemical properties such as soil EC, OM, total N, as well as available P and K relative to zeolite alone. It is concluded that the combined application of zeolite and biochar can mitigate NH₃ and greenhouse emissions and improve soil chemical characteristics, thus enhancing the environmental worth of arable farming.

Amalgamation and Scrutinizing of Leucine Derivatives Schiff bases Complexes as Antimicrobial Agent

The enhanced applications of Schiff bases metal complexes of amino acid derivatives have captured the attention of researchers for the synthesis of leucine derivatives of Schiff bases metal complexes. Amino acids are considered to be essential part of food supplements as well as derivatives of Schiff bases in coordination chemistry due to their donor ability. The leucine derivatives Schiff bases ligand have been synthesized by condensation reaction between amine of leucine with aldehyde or ketone bearing molecules attached with them. These complexes were characterized by different spectroscopic tools in order to confirm their structural geometries. The structural geometries are considered to be very important in order to improve the antimicrobial potential of leucine derivative metal complexes. By taking into account the antimicrobial potential of titled compounds, a comprehensive review of leucine derivatives of Schiff bases metal complexes has been compiled.

Electrochemical process for simultaneous removal of chemical and biological contaminants from drinking water

Simultaneous management of chemical and biological contaminants in drinking water has been presented through modification in conventional electrocoagulation (EC) process. Traditional EC process using iron and aluminum electrodes removed metals but did not affect microbiological contaminants to a greater extent. Iron anode composition was amended by addition of zinc for desired antimicrobial output. To evaluate the efficiency of this system, samples were spiked with multiple element standard and microbial cultures to human unsafe contamination level. Modified EC process removed both types of contaminants making water safe for human consumption within the prescribed regulatory guidelines set by WHO/NSDWQ within 4 min. This setup removed chemical contaminants up to 100% including nitrates, fluoride, arsenic, beryllium, chromium, copper, mercury, vanadium, zinc, nickel, phosphorus, and lead. A substantial removal in cadmium (89.8%), cobalt (75.7%), and selenium (46.7%) was computed. The treatment could not prove good results for removal of boron, barium, lithium, and strontium from the spiked sample. The compositional analysis of flocs screened after spiked sample treatment confirmed the physical adsorption of metals at floc surface. Treatment technique comprehensively proved equally efficient for disinfection of most common microbiological contaminations including E. Coli, fecal coliforms, total coliforms, total plate count, Staphylococcus auseous, and Pseudomonas aeruginosa within 5 min. In EC process 220V voltage was applied through rectifier at electrodes having 15.6 cm² surface area and 15 mm apart in 1-L water sample batches, where current varied from 0.8 to 1.6 ampere. The outcomes of the current experiment are of novel significance regarding simultaneous removal of metals and microbiological contaminants from drinking water which is not reported in previous treatment studies.

Optimization of process variables for increased production of lovastatin in Aspergillus terreus PU-PCSIR1 and its characterization

During intrinsic cholesterol formation 3-hydroxy-3-methylgutaryl coenzyme A reductase (HMGCR) converts HMGCoA to mevalonate, in biosynthetic cascade of cholesterol. Statins, competitive inhibitors of HMGCR, now-a-days commonly used to lower the blood-cholesterol level in the hyper-cholesterolemic patients. Lovastatin, one of the most potent natural statins, was produced from wild-type indigenous isolate Aspergillus terreus PU-PCSIR-1, through solid state fermentation (SSF). This study was carried out to investigate different parameters influencing lovastatin production such as pH, carbon source, nitrogen source and media components etc. Each parameter was investigated separately to optimize lovastatin production. Maximum yield of 2860mg/Kg of total lovastatin, comprising 1700 and 1160mg/Kg of hydroxy and lactone forms respectively, was achieved after incubating for 14 days, pH 5.5 and at 28°C. The integrity of biotechnologically-produced lovastatin was analyzed using high performance liquid chromatography (HPLC). Lovastatin was purified by preparative HPLC, and was characterized by FT-IR and LC-MS analyses. The study revealed that A. terreus PU-PCSIR-1 has been proved to be a potent strain for the production of lovastatin that has great pharmaceutical and commercial applications.

Application of lipase bearing dead mycelia as biocatalyst for octyl-octanoate synthesis

ABSTRACT

The present study scrutinizes lipases of different origins, immobilization methods, carriers, and reaction solvents to accelerate the octyl octanoate synthesis. The acylation reaction parameters including temperature, moisture level, shaking speed and enzyme dose were subsequently investigated and optimized following fully rotatable central composite design. The initial screening revealed that lipases of Rhizopus arrhizus, when applied as a biocatalyst (lipase bearing dead mycelia) furnished the highest acylation activity (147 μM L-1 min-1). Validation of reaction conditions disclosed that 250 I.U. of lipase based biocatalyst when incubated with 850 mM of acylating agent and 750 mM of the substrate at 35 °C, 3% moisture level and 150 RPM shaking speed produced 70% acylation yield with an acylation activity higher than 147 μM L-1 min-1. The observed results certify that lipase bearing dead mycelia of R. arrhizus might be an intelligent biocatalyst to manipulate the yield of acylation reactions encountered in the food industry.

GRAPHICAL ABSTRACT

Staphylococcus aureus carrying lukS/F Panton-Valentine Leukocidin (PVL) toxin genes in hospitals of Lahore city

INTRODUCTION

Panton Valentine-Leukocidin (PVL) toxin is secreted by Staphylococcus aureus and is mostly associated with skin and soft tissue infections (SSTI). This study aims to find out the prevalence of lukS/F-PV gene, which encode PVL toxin from strains of SSTI, burn wounds and nasal colonizers of out-patients and to measure the antimicrobial susceptibility of S. aureus isolates.

METHODOLOGY

This is an analytical observational cross-section study and was conducted from July 2014 to June 2015 at four tertiary care hospitals and PCSIR Laboratories Complex, Lahore, Pakistan. A total of 376 random clinical swabs were collected from SSTI (n = 179), nasal nares (n = 134) and burn wounds (n = 63) from out-patients' departments (OPD). The specimens were cultured on nutrient and mannitol salt agar (MSA) and the organism was identified by catalase, coagulase, and DNase tests. Antimicrobial susceptibility, methicillin, inducible clindamycin, and high-level mupirocin (HLMR) resistance were determined as per CLSI guidelines. Molecular identification of mecA and lukS/F-PV genes was performed by PCR.

RESULTS

We isolated 127 S. aureus, where 41 (32.3%) were MRSA and 86 (67.7%) were MSSA. All MRSA carried mecA gene whereas lukS/F-PV gene was found in 21 MRSA and 31 MSSA strains. Overall, a high antimicrobial resistance was found against MRSA and lukS/F-PV positive MSSA. Inducible clindamycin and high-level mupirocin resistance (HLMR) was 23.6% and 19.5% respectively.

CONCLUSIONS

A high rate of PVL toxin gene was detected among S. aureus strains and a high prevalence of antimicrobial resistant strains was observed.

Chromatographic resolution of angiotensin II receptor antagonists (sartans)

First time a simple, sensitive and unified quantification method has been developed to analyze the complete class of angiotensin II receptor antagonists which are used in the treatment of hypertension either alone or in combination with some other drugs. The most important advantage of developed method was that the eight separate drugs can be determined on a single chromatographic system without modifications in detection wavelength and mobile phase. The drugs were separated on a Purospher Star 4.6mm×25cm, 5μm, C18 column maintained at 40°C with 1mLmin(-1) flow rate using ultra violet detection at 254nm. Good separation (Rs>2.0) was achieved in a short analysis allowing simultaneous determination of all eight sartans. The effect of variation in flow rate, detection wavelength and column oven temperature was also studied. The proposed method was statistically validated in terms of precision, accuracy, linearity, specificity and robustness. The newly developed method proved to be specific, robust and accurate for the quantification of eight sartans in commercial pharmaceutical formulations.

The Impact of Aging and Medical Status on Dysgeusia

Disorders of taste and smell can cause an aversion to food in a sick patient and therefore affect his/her ability to maintain optimal nutrition. This can lead to a reduced level of strength, muscle mass, function, and quality of life. Additionally, reduced ability to differentiate between various intensities or concentrations of a tastant can result in increased intake of salt and sugar and exacerbation of chronic diseases such as heart failure and diabetes. These implications can be heightened in the elderly, who are particularly frail and are challenged by polypharmacy and multiple comorbid conditions. In this article, we will review the prevalence, etiology, and management of taste disorders. Additionally, we will review the association between taste and smell disorders and how disorders of smell can affect perception of taste.

Chromatographic resolution of drug analogues: 3-hydroxy-3-methylglutarylcoenzyme A reductase inhibitors (statins)

A high performance liquid chromatographic method for the simultaneous determination both qualitative and quantitative of cholesterol lowering statin drugs in pharmaceutical formulations has been developed. The most important advantage of developed method is that all seven statin drugs can be determined on a single chromatographic system without modification in detection wavelength. An organic modifier addition (25% v/v methanol) in the presence of buffer (20mM ammonium acetate; pH 4.0 adjusted with dilute acetic acid) played a key role in the resolution of statin drugs in gradient elution with acetonitrile. The drugs were separated on a Purospher Star 4.6mm × 25cm, 5μm, C18 column maintained at 25°C with 1mLmin(-1) flow rate using ultra violet detection at 240nm. Good separation (Rs > 2.5) was achieved in a short analysis allowing simultaneous determination of all seven statins. The effect of variation in flow rate, detection wavelength and column oven temperature was also studied. The proposed method was statistically validated in terms of precision, accuracy, linearity, specificity and robustness. The newly developed method proved to be specific, robust and accurate for the quantification of seven statins in commercial pharmaceutical formulations.

Firearms in Frail Hands: An ADL or A Public Health Crisis!

The incidence of neurocognitive disorders, which may impair the ability of older adults to perform activities of daily living (ADLs), rises with age. Depressive symptoms are also common in older adults and may affect ADLs. Safe storage and utilization of firearms are complex ADLs, which require intact judgment, executive function, and visuospatial ability, and may be affected by cognitive impairment. Depression or cognitive impairment may cause paranoia, delusions, disinhibition, apathy, or aggression and thereby limit the ability to safely utilize firearms. These problems may be superimposed upon impaired mobility, arthritis, visual impairment, or poor balance. Inadequate attention to personal protection may also cause hearing impairment and accidents. In this article, we review the data on prevalence of firearms access among older adults; safety concerns due to age-related conditions; barriers to addressing this problem; indications prompting screening for firearms access; and resources available to patients, caregivers, and health care providers.

Isolation, Characterization and Selection of Avermectin-Producing Streptomyces avermitilis Strains From Soil Samples

Background:

Streptomyces avermitilis, belonging to Actinomycetes, is specialized for production of avermectin, used as an anthelmintic and insecticidal agent. It is mostly found in soil and its isolation is very crucial for medically important avermectin production.

Objectives:

In the present study, 10 bacterial isolates lacking antimicrobial activities were isolated from the soil samples collected from different areas of Lahore, Pakistan.

Materials and Methods:

Three distinctive localities of Lahore were opted for soil assortment to isolate S. avermitilis. About 50 isolates of Streptomyces species were attained through selective prescreening procedures. All of these isolates were studied for production of the secondary metabolite, avermectin. Different test like soluble pigment color and melanin formation were used for identification. Biochemical characterizations of those isolates closely resembling the control in morphological characteristics, soluble pigment color and melanin formation tests were performed.

Results:

The 10 selected isolates were identified as the avermectin-producing strain by fermentation and characterized on ISP2 medium for aerial and reverse side mycelia color, soluble pigment color and melanin formation, in comparison with S. avermitilis DSM 41445. The best avermectin-producing isolate S1-C (10.15 mg/L) showed similar result as S. avermitilis DSM 41445, when subjected for culture characteristics analysis in different media along with biochemical characterization.

Conclusions:

From the results, it was concluded that agricultural lands around Pakistan Council of Scientific and Industrial Research (PCSIR) Campus Lahore were rich sources of industrially important Streptomyces, especially S. avermitilis.

An investigation into membrane bound redox carriers involved in energy transduction mechanism in Brevibacterium linens DSM 20158 with unsequenced genome

Brevibacterium linens (B. linens) DSM 20158 with an unsequenced genome can be used as a non-pathogenic model to study features it has in common with other unsequenced pathogens of the same genus on the basis of comparative proteome analysis. The most efficient way to kill a pathogen is to target its energy transduction mechanism. In the present study, we have identified the redox protein complexes involved in the electron transport chain of B. linens DSM 20158 from their clear homology with the shot-gun genome sequenced strain BL2 of B. linens by using the SDS-Polyacrylamide gel electrophoresis coupled with nano LC-MS/MS mass spectrometry. B. linens is found to have a branched electron transport chain (Respiratory chain), in which electrons can enter the respiratory chain either at NADH (Complex I) or at Complex II level or at the cytochrome level. Moreover, we are able to isolate, purify, and characterize the membrane bound Complex II (succinate dehydrogenase), Complex III (menaquinone cytochrome c reductase cytochrome c subunit, Complex IV (cytochrome c oxidase), and Complex V (ATP synthase) of B. linens strain DSM 20158.

Production and Screening of High Yield Avermectin B1b Mutant of Streptomyces avermitilis 41445 Through Mutagenesis

Background:

Secondary metabolite production from wild strains is very low for economical purpose therefore certain strain improvement strategies are required to achieve hundred times greater yield of metabolites. Most important strain improvement techniques include physical and chemical mutagenesis. Broad spectrum mutagenesis through UV irradiation is the most important and convenient physical method.

Objectives:

The present study was conducted for enhanced production of avermectin B1b from Streptomyces avermitilis 41445 by mutagenesis using ultraviolet (UV) radiation, ethidium bromide (EB), and ethyl methanesulfonate (EMS) as mutagens.

Materials and Methods:

S. avermitilis DSM 41445 maintained on yeast extract malt extract glucose medium (YMG) was used as inoculum for SM2 fermentation medium. Spores of S. avermitilis DSM 41445 were exposed to UV radiation for physical broad spectrum mutagenesis and to EMS and EB for chemical mutagenesis. For each mutagen, the lethality rate and mutation rate were calculated along with positive mutation rate.

Results:

Avermectin B1b-hyper-producing mutant, produced using these three different methods, was selected according to the HPLC results. The mutant obtained after 45 minutes of UV radiation to the spores of S. avermitilis 41445, was found to be the best mutant for the enhanced production of avermectin B1b component (254.14 mg/L). Other avermectin B1b-hyper-producing mutants, were obtained from EMS (1 µL/mL) and EB (30 µL/mL) treatments, and yielded 202.63 mg/L and 199.30 mg/L of B1b, respectively.

Conclusions:

The hereditary stability analysis of the UV mentioning 45 minutes revealed the UV exposure time for mutants and 3 represented the colony taken from the plate irradiated for 45 minutes mutant showed that the production of avermectin B1b remained constant and no reverse mutation occurred after 15 generations.