Human populations are using oceans as their household dustbins, and microplastic is one of the components which are not only polluting shorelines but also freshwater bodies globally. Microplastics ...are generally referred to particles with a size lower than 5 mm. These microplastics are tiny plastic granules and used as scrubbers in cosmetics, hand cleansers, air-blasting. These contaminants are omnipresent within almost all marine environments at present. The durability of plastics makes it highly resistant to degradation and through indiscriminate disposal they enter in the aquatic environment. Today, it is an issue of increasing scientific concern because these microparticles due to their small size are easily accessible to a wide range of aquatic organisms and ultimately transferred along food web. The chronic biological effects in marine organisms results due to accumulation of microplastics in their cells and tissues. The potential hazardous effects on humans by alternate ingestion of microparticles can cause alteration in chromosomes which lead to infertility, obesity, and cancer. Because of the recent threat of microplastics to marine biota as well as on human health, it is important to control excessive use of plastic additives and to introduce certain legislations and policies to regulate the sources of plastic litter. By setup various plastic recycling process or promoting plastic awareness programmes through different social and information media, we will be able to clean our sea dustbin in future.
Microplastic pollution is one of the emerging threats across the globe and is becoming a topic of intense study for environmental researchers. At present, almost all of the world’s oceans and seas ...are contaminated with microplastics but the Mediterranean Sea has been recognized as a target hotspot of the world as the microplastic concentration in this region is approximately four times greater than the North Pacific Ocean. Because of the distinguishing semi-enclosed morphology of the Mediterranean Sea, and different plastic waste generating activities originating from surrounding countries the Mediterranean Sea is highly vulnerable to microplastic pollution. Different plastic families have been reported in the Mediterranean Sea and the Physico-chemical features of these plastic polymers play an important role in the interactions between these plastic particles and other organic matter in the water bodies. The ingestion of microplastics by marine animals is an issue of concern as microplastic acts as vectors for other harmful pollutants adsorbed onto their surface. This review provides a detailed discussion on the persistence of microplastics in the Mediterranean Sea that have been identified in surface water and also in sediments and deep sea-floor. Various sources of these synthetic materials and the intensity of low and high-density polymers pollution in the Mediterranean Sea have also been discussed. This review also focuses on the threatened species in the Mediterranean Sea and the fate of the plastisphere community in its ecosystem. In the end, we highlight a series of important regulations and policies adopted by Mediterranean countries to control and manage the microplastic pollution in this region.
Antibiotics play an essential role in the medical healthcare world, but their widespread usage and high prevalence have posed negative environmental consequences. During the past few decades, various ...antibiotic drugs have been detected in aquatic and terrestrial ecosystems. Among them, the Fluoroquinolones (FQ) group is ubiquitous in the environment and has emerged as a major environmental pollutant. FQs are very significant, broad-spectrum antibiotics used in treating various pathogenic diseases of humans and animals. The most known and used FQs are ciprofloxacin, norfloxacin, ofloxacin, levofloxacin, enrofloxacin, danofloxacin, and moxifloxacin. After human and animal administration, about 70% of these drugs are excreted out in unaltered form into the environment. Besides, wastewater discharge from pharmaceutical industries, hospitals, and agriculture runoff is the major contributor to the accumulation of FQs into the ecosystem. Their long-term presence in the environment creates selection pressure on microorganisms and contributes to the emergence of multi-drug-resistant bacteria. In addition to the resistance, these antibiotics also impose ecotoxicological effects on various animals and plant species. The presence of the fluorine atom in Fluoroquinolones makes them highly electronegative, strong, recalcitrant, and less compatible with microbial degradation. Many biological and chemical processes have been invented and successfully implemented during the past few decades for the elimination of these pollutants from the environment. This review provides a detailed overview of the classification, occurrence, distribution, and ecotoxicological effects of Fluoroquinolones. Their modes of action, resistance mechanism, detection and analysis methods, and remediation strategies have also been discussed in detail.
•Fluoroquinolones are broad-spectrum antibiotics and ubiquitous in the environment.•Pharma industries, hospitals, and agriculture runoff are the major FQ contributors.•Multi-drug resistant bacteria generate due to FQ's selection pressure on microbes.•Classification, occurrence, and ecotoxicological effects of FQ have been discussed.•Resistance mechanism, detection, and remediation strategies have been summarized.
Although medical literature shows that children are minimally susceptible to 2019-Corona virus disease (COVID-19), they are hit the hardest by psychosocial impact of this pandemic. Being quarantined ...in homes and institutions may impose greater psychological burden than the physical sufferings caused by the virus. School closure, lack of outdoor activity, aberrant dietary and sleeping habits are likely to disrupt children's usual lifestyle and can potentially promote monotony, distress, impatience, annoyance and varied neuropsychiatric manifestations. Incidences of domestic violence, child abuse, adulterated online contents are on the rise. Children of single parent and frontline workers suffer unique problems. The children from marginalized communities are particularly susceptible to the infection and may suffer from extended ill-consequences of this pandemic, such as child labor, child trafficking, child marriage, sexual exploitation and death etc. Parents, pediatricians, psychologists, social workers, hospital authorities, government and non-governmental organizations have important roles to play to mitigate the psychosocial ill-effects of COVID-19 on children and adolescents. To provide the basic amenities, social security, medical care, and to minimize the educational inequities among the children of the different strata of the society are foremost priorities.
Here, we have analyzed the enzyme ornithine carbamoyltransferase (OCTase) in different classes of microorganisms belonging to psychrophiles, mesophiles and thermophiles. This OCTase catalyzes the ...formation of citrulline from carbamoyl phosphate (CP) and ornithine (ORN) in arginine biosynthesis pathway and has certain unique adaptations to regulate metabolic pathways in extreme conditions. The tertiary structure of OCTase showed two binding domains, the CP domain and ORN-binding domain at N and C terminals, respectively. We propose general acid–base catalysis in
Pseudomonas gessardii
between His259 and Asp220 in which later may act as a recipient of proton in the process. The comparative docking analysis showed that substrate-binding loops have been evolved to accommodate their lifestyles across the physiological temperature range where two substrates bind on two distinct loops in psychrophiles and mesophiles, whereas both the substrates bind on a single-substrate-binding loop in thermophiles and bring down the flexibility of the active site pocket to improve its evolutionary fitness.
Soils host diverse communities of interacting microbes and the nature of interspecific interactions is increasingly recognized to affect ecosystem-level processes. Antagonistic interactions between ...bacteria and fungi are of particular relevance for soil functioning. A number of soil bacteria produce secondary metabolites that inhibit eukaryotic growth. Antibiosis may be stimulated in the presence of competing bacteria, and we tested if biodiversity within bacterial communities affects their antagonistic activity against fungi and fungal-like species. We set up
Pseudomonas
communities of increasing diversity and measured the production of the broad spectrum antifungal compound 2,4-DAPG and their antagonistic activity against different eukaryotes. Diversity increased DAPG concentration and antifungal activity, an effect due to a combination of identity and interactions between species. Our results indicate that investment of pseudomonads into broad spectrum anti-eukaryotic traits is determined by both community composition and diversity and this provides new avenues to understand interactions between bacterial and fungal communities.
This paper addresses energy efficiency (EE)-spectrum efficiency (SE) trade-off in an energy harvesting (EH) cooperative cognitive radio network operated in a frame structure comprising of spectrum ...sensing (SS) and cooperation-transmission mode. The secondary users (SUs) are clustered into two groups and function in a way that when the SUs in Group I participate in cooperative SS, the SU nodes in Group II harvest energy from the radio frequency signal of primary user (PU). If PU is detected to be in transmit mode, the SU nodes in Group II cooperate in PUs transmission while the SUs in Group I perform EH. All the SU nodes transmit data when PU is detected idle. The objective is to maximize EE and SE via joint optimization of SS time, final decision threshold, self and cooperative transmission power gains. Mathematical analysis is done to solve the problem of EE-SE trade-off under the constraints of SS reliability, SU power budget, PU cooperative SE and fairness in SE for each SU. Numerical results highlight about 19% and 14% gain in normalized EE and SE values, respectively, compared to the existing work and the issue of EE-SE trade-off is clearly investigated.
Department of Microbiology, Bose Institute, Kolkata 700054, India
Correspondence Tapan K. Dutta tapan{at}bic.boseinst.ernet.in
Staphylococcus sp. strain PN/Y, capable of utilizing phenanthrene as a ...sole source of carbon and energy, was isolated from petroleum-contaminated soil. In the degradation of phenanthrene by strain PN/Y, various metabolites, isolated and identified by a combination of chromatographic and spectrometric analyses, revealed a novel phenanthrene assimilation pathway involving 2-hydroxy-1-naphthoic acid. Metabolism of phenanthrene was initiated by the dioxygenation on the 1,2-position of phenanthrene followed by meta -cleavage of phenanthrene-1,2-diol, leading to 2-hydroxy-1-naphthoic acid, which was then processed via a novel meta -cleavage pathway, leading to the formation of trans -2,3-dioxo-5-(2'-hydroxyphenyl)-pent-4-enoic acid and subsequently to salicylic acid. In the lower pathway, salicylic acid was transformed to catechol, which was then metabolized by catechol-2,3-dioxygenase to 2-hydroxymuconaldehyde acid, ultimately forming TCA cycle intermediates. The catabolic genes involved in phenanthrene degradation were found to be plasmid-encoded. This detailed study of polycyclic aromatic hydrocarbon (PAH) metabolism by a Gram-positive species involving a unique ring-cleavage dioxygenase in a novel phenanthrene degradation pathway provides a new insight into the microbial degradation of PAHs.
Abbreviations: d 6 -DMSO, deuterated DMSO; ESI, electrospray ionization; PAH, polycyclicaromatic hydrocarbon
The GenBank/EMBL/DDBJ accession number for the sequence determined in this study is DQ404012.
If the 20th century was the revolution era of plastic industry for manufacturing too many plastic based products starting from bucket to car, then the 21st century is the time to face its ...consequences. Improper management, lack of information about its negative effect and irresponsible use as well as dumping of plastic products turns this planet into “plastic planet”. Besides emerging as solid waste, these plastic materials also appeared as a great threat for human and animal health. It not only polluted the roads, forests, mountains but also polluted our oceans. Ignorant human populations always throw the plastic waste into water bodies and most probably the “out of sight out of mind” thought leads them to do so. This is why the problem of microplastics in the marine ecosystem is an issue of great concern nowadays.Here we discuss the different sources of microplastics in the oceans and their harmful impacts on the marine organisms. The microscopic size of these plastic fragments gets them easily available for ingestion by an array of marine habitants, causing adverse effects on their health. The potential of microplastics to absorb various harmful hydrophobic pollutants from the surrounding environment indirectly transfers these contaminants in the food chain. Thus to tackle this serious issue of microplastic pollution in the marine ecosystem, various policies and rules must be formulated. To avoid future threat, it is important to stop producing it further and replace the plastic with alternative eco‑friendly materials.
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