85 research outputs found

    Paleoclimatic and diagenetic history of the Late Quaternary sediments in a core from the Southeastern Arabian Sea: geochemical and magnetic signals

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    Geochemical and rock-magnetic investigations were carried out on a sediment core collected from the SE Arabian Sea at 1420 m depth in oxygenated waters below the present-day oxygen minimum zone. The top 250 cm of the core sediments represent the last 35 kaBP. The δ18O values of Globigerinoides ruber are heaviest during the Last Glacial Maximum (LGM) and appear unaffected by low-saline waters transported from the Bay of Bengal by the strong northeast monsoon and West Indian coastal current. The signatures of Bølling-Allerød and Younger Dryas events are distinct in the records of magnetic susceptibility, organic carbon (OC) and δ 18O. Glacial sediments show higher OC, CaCO3, Ba, Mo, U and Cd, while the early-to-late Holocene sediments show increasing concentrations of OC, CaCO3, Ba, Cu, Ni and Zn and decreasing concentrations of Mo, U and Cd. Productivity induced low-oxygenated bottom waters and reducing sedimentary conditions during glaciation, and productivity and oxygenated bottom waters in the Holocene are responsible for their variation. The core exhibits different stages of diagenesis at different sediment intervals. The occurrence of fine-grained, low-coercivity, ferrimagnetic mineral during glacial periods is indicative of its formation in organic-rich, anoxic sediments, which may be analogous to the diagenetic magnetic enhancement known in sapropels of the Mediterranean Sea and Japan Sea. The glacial sediments exhibiting reductive diagenesis with anoxic sedimentary environment in this core correspond to reductive diagenesis and intermittent bioturbation (oxygenation) reported in another core in the vicinity. This suggests that the poorly oxygenated bottom water conditions during glacial times should not be generalized, but are influenced locally by productivity, sedimentation rates and sediment reworking

    Rock magnetic and geochemical record in a sediment core from the Eastern Arabian Sea: diagenetic and environmental implications during the late Quaternary

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    Rock magnetic concentration, grain size and mineralogy parameters together with organic carbon, calcium carbonate, redox-sensitive elements, δ18O of Globigerinoides ruber and radiocarbon dating were carried out on a 445 cm long sediment core collected at 1380 m depth off Mangalore, southwestern margin of India. The top 290 cm sediments of the core correspond to the last 18 kaBP. The δ18O and magnetic records exhibit major events at ∼ 16 kaBP, 14.5 kaBP, 11.5 kaBP and 9.8/8.6 kaBP related to start and intensity of the summer monsoon and climate change, and are synchronous with that of the western Arabian Sea and North Atlantic. The sediments with high magnetic susceptibility correlate with high sedimentation rates. The sediments are dominated by fine-grained magnetite, but intervals of 1.2-3.8 kaBP and 10-13.5 kaBP were subjected to diagenetic changes, resulting in the dissolution of fine-grained magnetites and enrichment of redox-sensitive trace elements (Cu, Ni, Zn, V, Mo and U). The sediments between 290 cm and 445 cm correspond to 18-27 kaBP and are characterized by distinct decrease in magnetic concentration, grain size and mineralogy parameters, high organic carbon, low concentrations of redox-sensitive trace elements and abundant pyritized tubules. The reductive diagenetic conditions indicated by rock magnetic properties are in contrast with the weak sub-oxic conditions revealed by low concentrations of trace elements in the sediments. The seasonal organic matter flux produced during the winter monsoon and moderate sedimentation rates favoured reductive diagenesis in the sediments at and below the last glacial maximum (LGM). Intermittent bioturbation, however, allowed oxidants to penetrate into the sediments, remobilized redox-sensitive trace elements into the water column and modified the primary geochemical signal of the sedimentary environment

    Bio prospecting of Lapachol producing endophytic fungi

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    Background: The association of endophytic fungi with medicinal plants has been one of the evolving areas of research in the past few decades. The secondary metabolites produced owing to such associations have been recognised for a wide range of biological activities. Objectives: The aim of the present review is to highlight the isolation of lapachol from endophytic microorganisms with an emphasis on its biotransformation to improve its efficacy. Methodology: The researchers followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. Published scientific articles on endophytes, host-pathogen interaction and lapachol isolation were collected from reputed journals from 1960 to 2022 using electronic databases using the key words as stated. Following that, the authors chose the required papers based on the criteria they devised. The data was extracted using the common research elements found in the publications. Results and discussion: Lapachol is one such secondary metabolite known for potent antitumor properties. Synthesis of lapachol and its isolation from plant sources have been reported but an expensive process. Therefore, bioprospecting of this metabolite from endophytic fungi have been evaluated by a few researchers. It has been identified that A. niger and Alternaria alternata along with some of the filamentous endophytic fungi have been identified to produce lapachol. Some findings of biotransformation of lapachol to render it more potent have also been reported in the present review. Conclusion: Lapachol is one of the plant secondary metabolites that possess several therapeutic benefits. Owing to its isolation being highly expensive from plant sources, endophytes have been exploited. Furthering to the isolation, the biotrasformation of this bioactive molecule to enhance its efficiency has proven to be useful. In this regard, this review has enlightened some of the biotransformed lapachol and its derivatives with special emphasis on the endophytes that produce them. This review comprehensively highlights the various endophytic sources for lapachol production and its biotransformed derivatives

    Artificial intelligence and Machine Learning based Techniques in Analyzing the COVID-19 Gene Expression data: A Review

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    The novel Coronavirus associated with respiratory illness has become a new threat to human health as it is spreading very rapidly among the human population. Scientists and healthcare specialists throughout the world are still looking for a breakthrough technology to help combat the Covid-19 outbreak, despite the recent worldwide urgency. The use of Machine Learning (ML) and Artificial Intelligence (AI) in earlier epidemics has encouraged researchers by providing a fresh approach to combating the latest Coronavirus pandemic. This paper aims to comprehensively review the role of AI and ML for analysis of gene expressed data of COVID-1

    QUASISPECIES FEATURE IN SARS-CoV-2

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    Since the identification of the SARS-CoV-2, genus Beta- Coronavirus, in January 2020, the virus quickly spread in less than 3 months to all continents with a susceptible human population of about a 7.9billion, and still in active circulation. In the process, it has accumulated mutations leading to genetic diversity. Regular emergence of variants of concern/significance in different ecology shows genetic heterogeneity in the base population of SARS-CoV-2 that is continuously expanding with the passage of the virus in the vast susceptible human population. Natural selection of mutant occurs frequently in a positive sense (+) single-stranded (ss) RNA virus upon replication in the host.  The Pressure of sub-optimal levels of virus-neutralizing antibodies and also innate immunity influence the process of genetic/ antigenic selection. The fittest of the mutants, that could be more than one, propagate and emerge as variants. The existence of different lineages, clades, and strains, as well as genetic heterogeneity of plaque purified virus population, justifies SARS-CoV-2 as ‘Quasispecies’ that refers to swarms of mutant sequences generated during replication of the viral genome, and all mutant sequences may not lead to virion. Viruses having a quasispecies nature may end up with progressive antigenic changes leading to antigenic plurality that is driven by ecology, and this phenomenon challenges vaccination-based control programs

    Comparison of clinical efficacy of methylprednisolone and serratiopeptidase for reduction of postoperative sequelae after lower third molar surgery

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    Background: Surgical removal of mandibular third molars results in some degree of post-operative pain, swelling and trismus. These can be controlled by proper administration of local anesthesia, careful bone removal, minimal trauma to adjacent soft tissues and administration of methylprednisolone and serratiopeptidase drugs. The aim of the present study was to compare the efficacy of methylprednisolone and serratiopeptidase in controlling post- operative pain, swelling and trismus after surgical removal of impacted mandibular third molars. Material and Methods: The subjects were divided into two groups of 50 patients each undergoing surgical removal of mandibular third molars. Group A was given methylprednisolone 4mg orally every 8th hourly and Group B was given serratiopeptidase 10 mg every 12th hourly orally. Post-operatively pain, swelling and trismus were evaluated at the end of 1st, 3rd and 5thday. Results: The results of this study showed that methylprednisolone is an effective analgesic, while serratiopeptidase has moderate analgesic activity. Serratiopeptidase is more effective than methylprednisolone in controlling post surgical swelling and trismus. Hence combination of these two drugs would be very effective than individual drug when widespread post-operative sequelae are expected after surgical removal of impacted lower third molars. Conclusions: We conclude that methylprednisolone affords better pain relief while serratiopeptidase exerts better anti-inflammatory and anti-swelling effects in the post-operative period. Synergistic combinations of these two drugs would however prove to be more effective when extensive post-operative sequelae are expecte

    COVID-19 PANDEMIC: A SYSTEMATIC REVIEW ON THE CORONAVIRUSES OF ANIMALS AND SARS-CoV-2

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    Coronaviruses (CoVs), classified into four genera, viz., alpha-, beta-, gamma-, and Delta- CoV, represent an important group of diverse transboundary pathogens that can infect a variety of mammalian and avian species including humans, animals, poultry, and non-poultry birds. CoVs primarily infect lung and gut epithelial cells, besides monocytes and macrophages. CoVs have high mutation rates causing changes in host specificity, tissue tropism, and mode of virus excretion and transmissions. The recent CoV zoonoses are SARS, MERS, and COVID-19 that are caused by the transmission of beta-CoVs of bats to humans.  Recently, reverse zoonoses of the COVID-19 virus have been detected in dogs, tigers, and minks. Beta-CoV strains also infect bovine (BCoV) and canine species (CRCoV); both these beta-CoVs might have originated from a common ancestor. Despite the high genetic similarity between BCoV, CRCoV, and HCoV-OC43, these differ in species specificity. Alpha-CoV strains infect canine (CCoV), feline (FIPV), swine (TGEV and PEDV), and humans (HCoV229E and NL63). Six coronavirus species are known to infect and cause disease in pigs, seven in human beings, and two in dogs. The high mutation rate in CoVs is attributed to error-prone 3′-5′ exoribonuclease (NSP 14), and genetic recombination to template shift by the polymerase. The present compilation describes the important features of the CoVs and diseases caused in humans, animals, and birds that are essential in surveillance of diverse pool of CoVs circulating in nature, and monitoring interspecies transmission, zoonoses, and reverse zoonoses

    Research Article A new Informatics Framework for Evaluating the Codon Usage Metrics, Evolutionary Models and Phylogeographic reconstruction of Tomato yellow leaf curl virus (TYLCV) in different regions of Asian countries

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    Tomato yellow leaf curl virus (TYLCV) is a major devastating viral disease, majorly affecting the tomato production globally. The disease is majorly transmitted by the Whitefly. The Begomovirus (TYLCV) having a six major protein coding genes, among them the C1/AC1 is evidently associated with viral replication. Owing to immense role of C1/AC1 gene, the present study is an initial effort to elucidate the factors shaping the codon usage bias and evolutionary pattern of TYLCV-C1/AC1 gene in five major Asian countries. Based on publically available nucleotide sequence data the Codon usage pattern, Evolutionary and Phylogeographic reconstruction was carried out. The study revealed the presence of significant variation between the codon bias indices in all the selected regions. Implying that the codon usage pattern indices (eNC, CAI, RCDI, GRAVY, Aromo) are seriously affected by selection and mutational pressure, taking a supremacy in shaping the codon usage bias of viral gene. Further, the tMRCA age was 1853, 1939, 1855, 1944, 1828 for China, India, Iran, Oman and South Korea, respectively for TYLCV-C1/AC1 gene. The integrated analysis of Codon usage bias, Evolutionary rate and Phylogeography analysis in viruses signifies the positive role of selection and mutational pressure among the selected regions for TYLCV (C1/AC1) gene

    RMAC study:A randomized study for evaluation of metronomic adjuvant chemotherapy in recurrent head and neck cancers post salvage surgical resection in those who are ineligible for re-irradiation

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    Background: Adjuvant re-chemoradiation after salvage surgery improves disease-free survival in recurrent head and neck cancer. However, most patients are ineligible for re-irradiation and are kept on observation. We investigated the efficacy of metronomic adjuvant chemotherapy (MAC) in this group of patients compared to observation. Methods: This was a randomized integrated phase II/III clinical trial. Adults with recurrent head and neck cancer, who had undergone salvage surgery, but were ineligible for adjuvant re-irradiation were randomized in a 1:1 ratio to either MAC arm or observation. MAC consisted of weekly oral methotrexate (at a dose of 15 mg per square meter of body surface area) and celecoxib (at a dose of 200 mg orally twice daily) for 6 months. The primary endpoint of phase 2 was disease-free survival (DFS) while that of phase 3 was overall survival (OS). For phase 2, to detect an improvement in the hazard ratio (HR) 0.67 with MAC, with a type 1 error of 10% (1-sided), type 2 error of 30%, 105 patients were required. While for phase 3, with a target HR of 0.77, with a type 1 error of 5%, type 2 error of 20%, 318 patients were required. Here we report the results of phase 2 part of the study. Results: At a median follow up of 30.2 months (95% confidence interval (CI), 25.3 to 35.1) the 1 year and 2-year DFS were 57.4% (95% CI, 42.8–69.5) and 37.6% (95% CI, 24.1–51) in MAC arm whereas the corresponding numbers were 62.3% (95% CI, 47.8 to 73.8) and 54.2%(95% CI, 39.8 to 66.5) in observation arm, respectively (hazard ratio for progression, 1.45; 95% CI, 0.87 to 2.47; P = 0.15). In the MAC arm, the 1 and 2 year OS was 78.7% (95% CI, 64.9 to 87.6) and 48% (95% CI, 34.1 to 62).The corresponding figures in the observation arm were 79.2% (95% CI, 65.7 to 87.9) and 65.5% (95% CI, 50.9 to 76.7) (hazard ratio for death, 1.7, 95% CI, 0.94 to 3.08; P = 0.08). Conclusion: The adjuvant 6-month metronomic schedule was ineffective in improving outcomes in recurrent head and neck cancers post salvage surgery who are ineligible for re-radiation. Trial registration. Clinical trial registry of India (CTRI)- CTRI/2016/04/006872 [Registered on 26/4/2016] © 2022 Elsevier Lt
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