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Chromium (VI) a highly toxic metal, a major constituent of industrial waste. It is continuously release in soil and water, causes environmental and health related issues, which is increasing public concern in developing countries like Pakistan. The basic aim of this study was isolation and screening of chromium resistant bacteria from industrial waste collected from Korangi and Lyari, Karachi (24˚52ʹ46.0ʺN 66˚59ʹ25.7ʺE and 24˚48ʹ37.5ʺN 67˚06ʹ52.6ʺE). Among total of 53 isolated strains, seven bacterial strains were selected through selective enrichment and identified on the basis of morphological and biochemical characteristics. These strains were designated as S11, S13, S17, S18, S30, S35 and S48, resistance was determined against varying concentrations of chromium (100-1500 mg/l). Two bacterial strains S35 and S48 showed maximum resistance to chromium (1600 mg/l). Bacterial strains S35 and S48 were identified through 16S rRNA sequence and showed 99% similarity to Bacillus paranthracis and Bacillus paramycoides. Furthermore, growth condition including temperature and pH were optimized for both bacterial strains, showed maximum growth at temperature 30ºC and at optimum pH 7.5 and 6.5 respectively. It is concluded that indigenous bacterial strains isolated from metal contaminated industrial effluent use their innate ability to transform toxic heavy metals to less or nontoxic form and can offer an effective tool for monitoring heavy metal contamination in the environment. Resumo O cromo (VI), metal altamente tóxico, é um dos principais constituintes dos resíduos industriais. É liberado no solo e na água, causa problemas ambientais e de saúde de crescente preocupação pública em países em desenvolvimento como o Paquistão. O objetivo básico deste estudo foi o isolamento e a triagem de bactérias resistentes ao cromo de resíduos industriais coletados em Korangi e Lyari, Karachi (24˚52’46,0”N 66˚59’25,7”E e 24˚48’37,5”N 67˚06’52,6”E). Do total de 53 cepas isoladas, sete cepas bacterianas foram selecionadas por enriquecimento seletivo e identificadas com base em características morfológicas e bioquímicas. Essas cepas foram designadas como S11, S13, S17, S18, S30, S35 e S48, apresentaram alta resistência aos metais contra concentrações variáveis (100-1500 mg / l) de cromo. Já as cepas S35 e S48 foram identificadas por meio da sequência 16S rRNA e apresentaram 99% de similaridade com Bacillus paranthracis e Bacillus paramycoides. Além disso, as condições de crescimento incluindo temperatura e pH foram otimizadas e ambas as cepas bacterianas apresentaram crescimento máximo na temperatura de 30 ºC, enquanto seu pH ótimo foi observado em 7,5 e 6,5, respectivamente. Conclui-se que o potencial de resistência dessas bactérias resistentes ao cromo pode ser efetivamente utilizado na remoção de cromo de efluentes industriais contaminados. Técnicas de base biológica usando bactérias ajudarão a fornecer métodos mais baratos e ecológicos de remoção, recuperação e desintoxicação de cromo.

The environmental release of mercury is continuously increasing with high degree of mobility, transformation and amplified toxicity. Improving remediation strategies is becoming increasingly important to achieve more stringent environmental safety standards. This study develops a laboratory-scale reactor for bioremediation of aqueous mercury using a biofilm-producing bacterial strain, KBH10, isolated from mercury-polluted soil. The strain was found resistant to 80 mg/L of HgCl2 and identified as Bacillus nealsonii via 16S rRNA gene sequence analysis. The strain KBH10 was characterized for optimum growth parameters and its mercury biotransformation potential was validated through mercuric reductase assay. A packed-bed column bioreactor was designed for biofilm-mediated mercury removal from artificially contaminated water and residual mercury was estimated. Strain KBH10 could grow at a range of temperature (20–50 °C) and pH (6.0–9.0) with optimum temperature established at 30 °C and pH 7.0. The optimum mercuric reductase activity (77.8 ± 1.7 U/mg) was reported at 30 °C and was stable at a temperature range of 20–50 °C. The residual mercury analysis of artificially contaminated water indicated 60.6 ± 1.5% reduction in mercury content within 5 h of exposure. This regenerative process of biofilm-mediated mercury removal in a packed-bed column bioreactor can provide new insight into its potential use in mercury bioremediation. HIGHLIGHTS Bioaccumulation of aqueous mercury in the food web is a matter of grave concern.; Enzymatic reduction of mercury by resistant bacteria reduces its potential toxicity.; Bacillus nealsonii possess the inbuilt mechanisms of necessary adaptation.; Mercury content was reduced up to 60.6 ± 1.5% within 5 h of exposure in packed-bed bioreactor.; Biofilm-mediated mercury remediation is efficient, regenerative and cost-effective.

Cadmium-tolerant fungus, designated as strain FMS2, was isolated from metal-polluted soil collected from Lahore, Pakistan, and its role in cadmium bioremediation was investigated. Strain FMS2 was identified as Penicillium chrysogenum through sequence analysis of the internal transcribed spacer (ITS) regions. Physicochemical growth factors and maximum tolerance level to cadmium were determined. Cadmium uptake and bioremoval potential were analyzed by atomic absorption spectrophotometry, scanning electron microscopy and energy-dispersive spectroscopic analysis, whereas its distribution inside the fungal cell was detected by scanning transmission electron microscopy and electron energy loss spectroscopy. P. chrysogenum FMS2 was found to be resistant to cadmium with a maximum tolerance level up to 1000 mg l−1. Strain FMS2 can grow under a wide range of temperature (15–35 °C) and pH conditions (4.0–12.0). The cadmium removal capacity of strain FMS2 was observed as 49 ± 0.8% within 15 days after exposure. Distinct white patches were observed in scanning electron micrographs with clear peaks of cadmium in energy-dispersive spectroscopic spectra indicating cadmium biosorption. The scanning transmission electron micrographs and electron energy loss spectra of strain FMS2 cells revealed cytoplasmic localization of cadmium.

A bacterium designated as strain STP14 was isolated from a sewage treatment plant and identified as Acinetobacter calcoaceticus based on 16S ribosomal RNA gene sequencing. Strain STP14 exhibited resistance to several metals such as mercury, cobalt, copper, nickel, lead, and cadmium. Among these metals, the bacterium showed maximum resistance to cadmium in concentration up to 1200 mg/L. The antimicrobial susceptibility test of A. calcoaceticus strain STP14 showed coresistance to all tested antibiotics except tigecycline and chloramphenicol for which 16 ± 1- and 15 ± 1-mm zone of inhibition was observed, respectively. The protein pattern of the crude cellular extract revealed substantial differences in protein bands of untreated control and cadmium treated A. calcoaceticus strain STP14 suggesting variable protein expression under cadmium stress. Metals and antibiotic resistance are increasing phenomenon and universal concern of public health. This study improves our understanding regarding the bacterial coresistance against metals and antibiotics and the possible emergence of multidrug resistance due to selective pressure and coselection in the metal polluted sewage sludge.

High-throughput sequencing approach of the 16S rRNA gene was employed to evaluate the bacterial diversity inhabit in melted water, snow, soil, and rocks samples at the lower altitudes of the Laohug...

Pigments are an essential part of everyday life on Earth with rapidly growing industrial and biomedical applications. Synthetic pigments account for a major portion of these pigments that in turn have deleterious effects on public health and environment. Such drawbacks of synthetic pigments have shifted the trend to use natural pigments that are considered as the best alternative to synthetic pigments due to their significant properties. Natural pigments from microorganisms are of great interest due to their broader applications in the pharmaceutical, food, and textile industry with increasing demand among the consumers opting for natural pigments. To fulfill the market demand of natural pigments new sources should be explored. Cold-adapted bacteria and fungi in the cryosphere produce a variety of pigments as a protective strategy against ecological stresses such as low temperature, oxidative stresses, and ultraviolet radiation making them a potential source for natural pigment production. This review highlights the protective strategies and pigment production by cold-adapted bacteria and fungi, their industrial and biomedical applications, condition optimization for maximum pigment extraction as well as the challenges facing in the exploitation of cryospheric microorganisms for pigment extraction that hopefully will provide valuable information, direction, and progress in forthcoming studies.

This study aims to determine UV-B resistance and to investigate computational analysis and antioxidant potential of methoxy-flavones of Micromonospora aurantiaca TMC-15 isolated from Thal Desert, Pakistan. The cellular extract was purified through solid phase extraction and UV-Vis spectrum analysis indicated absorption peaks at λmax 250 nm, 343 nm, and 380 nm that revealed the presence of methoxy-flavones named eupatilin and 5-hydroxyauranetin. The flavones were evaluated for their antioxidant as well as protein and lipid peroxidation inhibition potential using di(phenyl)-(2,4,6-trinitrophenyl) iminoazanium (DPPH), 2,4-dinitrophenyl hydrazine (DNPH), and thiobarbituric acid reactive substances (TBARS) assays, respectively. The methoxy-flavones were further studied for their docking affinity and interaction dynamics to determine their structural and energetic properties at atomic level. The antioxidant potential, protein and lipid oxidation inhibition and DNA damage preventive abilities were correlated as predicted by computational analysis. The eupatilin and 5-hydroxyauranetin binding potential to their targeted proteins 1N8Q and 1OG5 is -4.1 and -7.5 kcal/mol, respectively. Moreover, the eupatiline and 5-hydroxyauranetin complexes illustrate van der Waals contacts and strong hydrogen bonds to their respective enzymes target. Both in-vitro studies and computational analysis results revealed that methoxy-flavones of Micromonospora aurantiaca TMC-15 can be used against radiation mediated oxidative damages due to its kosmotrophic nature. The demonstration of good antioxidant activities not only protect DNA but also protein and lipid oxidation and therefore could be a good candidate in radio-protective drugs and as sunscreen due to its kosmotropic nature.

The aim of the current study was gut profiling of culturable Candida species and their possible pathogenic potential to asses role in obesity.This case control study includes stool samples from 75 obese individuals and 50 controls. Isolation and identification of various Candida species was carried out by standard microbiological techniques. For pathogenic profiling, extracellular enzymatic assays, biofilm forming ability and resistance to azole were analyzed.Culturable gut profiling identified comparative higher abundance and diversity of Candida species among obese compared to controls. The most abundant specie among both groups was C.kefyr. A comparatively higher pathogenic potential as more hydrolases expression was detected in C.kefyr, C.albicans and Teunomyces krusei from obese group. Majority isolates from obese group were strong biofilm formers (47.1%) compared to control group (35.4%) suggesting it as strong risk factor for obesity. Fluconazole resistance was highest among C.kefyr (51%) followed by Teunomyces krusei and C.albicans. All the isolates from different species were voriconazole sensitive except C.kefyr displaying a 4.2% resistance in obese group only. A significant association of dominant colonizing species with meat, fruit/vegetable consumption and residence area was present (p 0.05).The presence of hydrolytic enzymes in gut Candida species showed strong association with protein's degradation and enhanced pathogenicity. C.kefyr and Teunomyces krusei has emerged as potential pathogen showing increased colonization as result of protein rich and low carb diet. Thus presenting it as a bad choice for weight loss in obese individuals.

Metallotolerant fungi are known for their ability to adapt to high concentrations of heavy metals by producing extracellular metabolites. We isolated an acid-producing filamentous fungus, designate...

Aim Escherichia coli is the conventional choice as the host strain for whole-cell bioreporter construction due to its well-understood genetics and well-established cloning protocols. However, for real-world environmental biosensing applications, it is often beneficial to use a bacterial strain derived directly from the environment under study to better ensure chemical target specificity and optimal response time. The aim of this study was to develop a whole-cell bioreporter for detection of bioavailable mercury by replacing E. coli with a wild-type bacterial host derived from a soil environment. Materials and results In this study, an Enterobacter cloacae strain isolated from soil derived from a municipal and electronic waste dumping site was engineered to serve as a bioluminescent bioreporter for mercury toxicity by linking its merR-like gene and promoter sequence to a reorganized luxABCDE gene cassette from Photorhabdus luminescens. This bioreporter, designated as E. cloacae DWH4lux , detected mercury (HgCl2 ) at a minimum concentration of 0·2 µg l-1 with a linear response profile being maintained between a range of 0·4-1600 µg l-1 (R2 = 0·9604) with a peak bioluminescent response occurring within 1 h after exposure. No significant synergistic or antagonistic influences were observed on the bioluminescent response by other contaminating metal elements. Enterobacter cloacae DWH4lux was also demonstrated to detect mercury effectively in artificially contaminated water sample with linear correlation (R2 = 0·9623). Conclusions The results indicated that E. cloacae DWH4lux could detect mercury in quantities below the US Environmental Protection Agency's permitted limit values (2 µg l-1 ). Hence, it is concluded that E. cloacae DWH4lux has the potential to serve as an effective whole-cell bioreporter for the environmental monitoring of mercury contamination. Significance and impact of the study This study provides new insight into the recruitment of mercury-tolerant bacterial hosts derived from environmental samples over the conventional lab-based E. coli host for the construction of mercury bioreporters. With improved response time and selectivity, the environmentally sourced bacteria can serve as an alternative host choice to improve biosensing technology in the near future.

Nowadays, due to fast global industrial progress and near diminution of high-grade ore reserves, there has been massive call to cost-effectively process the resources of low-grade ores and industrial effluents for metal extraction. However, conventional approaches cannot be used to process such resources due to high capital cost and energy, also causing environmental pollution. Alternatively, bioleaching is highly environmental friendly and economic method to process such resources. Metal recovery from metal sulfide ore is carried out by chemolithotrophic bacteria like Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. The same is done by heterotrophic microorganisms in non-sulfide ores. Additionally, for gold and copper extractions, bioleaching is used to extract cobalt, zinc, nickel, and uranium from low-grade ores and industrial effluents. In this review, the fundamental process of bioleaching from low-grade metal sulfide ores are discussed with emphasis on mechanism, types, pathways, techniques, and bioleaching development.

The present world faces a new threat of ancient microbes and resistomes that are locked in the cryosphere and now releasing upon thawing due to climate change and anthropogenic activities. The cryosphere act as the best preserving place for these microbes and resistomes that stay alive for millions of years. Current reviews extensively discussed whether the resurrection of microbes and resistomes existing in these pristine environments is true or just a hype. Release of these ancient microorganisms and naked DNA is of great concern for society as these microbes can either cause infections directly or they can interact with contemporary microorganisms and affect their fitness, survival, and mutation rate. Moreover, the contemporary microorganisms may uptake the unlocked naked DNA, which might transform non-pathogenic microorganisms into deadly antibiotic-resistant microbes. Additionally, the resurrection of glacial microorganisms can cause adverse effects on ecosystems downstream. The release of glacial pathogens and naked DNA is real and can lead to fatal outbreaks; therefore, we must prepare ourselves for the possible reemergence of diseases caused by these microbes. This study provides a scientific base for the adoption of actions by international cooperation to develop preventive measures.

Objective To evaluate current situation regarding the prevalence of hepatitis C virus (HCV) in thalassemic patients visiting a thalassemia centre in Rawalpindi District, Pakistan for supportive therapy. Methods Serum samples were screened for hepatitis B surface antigen and anti-HCV by using commercially available ELISA kit. Micro-plate reader was used to perform analysis based on the absorbance/cut-off ratios. Samples were considered positive or negative. Results from ELISA were analyzed statistically. Results A total of 95 subjects were observed to have β-thalassemia major (96%) and β-thalassemia intermedia (4%). Among these, 47 (49%) were detected positive for anti-HCV antibodies and three for hepatitis B surface antigen. All recruited subjects were observed for therapy/medication behavior and clinical complications. About 83 (87%) patients were on chelation therapy, and overall complications (hepatomegaly, splenomegaly and splenectomy) were observed in 81% individuals. The distribution of disease status (thalassemia and hepatitis) was not significantly associated with gender, age, origin, province, socio-economic status and parental marriage type ( P >0.05). The distributions of ferritin levels, therapy/medication and complications were assessed across demographic variables. Thalassemic subjects were distributed with respect to their sporadic and familial presentations. Among the familial cases ( n =35), a total of 93 subjects were found to be affected. Parity was scored for the index cases, and majority belonged to second parity (29%), followed by first and third parities (25% and 15%, respectively). The sibship size was increasing with increasing parity level. Conclusions Although standardized blood screening procedures are supposed to be implemented, higher prevalence of HCV in thalassemic patients requires greater attention in Pakistan. Furthermore, a poor compliance regarding iron chelation therapy has been observed in this study.