Degradation of crude oil-associated polycyclic aromatic hydrocarbons by marine-derived fungi.

One of the major environmental concerns today is hydrocarbon contamination resulting from the activities related to the petrochemical industry. Crude oil is a complex mixture of hydrocarbons like alkanes, naphthene and polycyclic aromatic hydrocarbons (PAHs). PAHs are known to be highly toxic to humans and animals due to their carcinogenic and mutagenic effects. PAHs are environmentally recalcitrant due to their hydrophobicity which makes them difficult to degrade, thus making them persistent environmental contaminants. The mechanical and chemical methods in practice currently to remove hydrocarbon contaminants have limited effectiveness and are expensive. Bioremediation is a cost-effective technology for treating hydrocarbon-contaminated sites as it results in the complete mineralisation of the pollutant. This study demonstrates the degradation of crude oil and associated PAHs using ten fungal cultures isolated from the aquatic environment. The current study reported a 98.6% and 92.9% reduction in total PAHs in crude oil by Fusarium species, i.e. isolate NIOSN-T4 and NIOSN-T5, respectively. The fungal isolate, NIOSN-T4, identified as Fusarium equiseti, showed maximum PAH degradation efficiency of LMW PAHs 97.8%. NIOSN-M126, identified as Penicillium citrinum, exhibited a 100% removal of HMW PAHs. Microorganisms possess an untapped potential for various applications in biotechnology, and the current study demonstrated the potential of marine fungi for use in the bioremediation of xenobiotic hydrocarbons in the environment. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03753-2.

Risk assessment of polycyclic aromatic hydrocarbon infested sediments along the coast of Goa, India.

Goa, a small state in India, is a tourist hotspot known for its coastline and beaches. Anthropogenic activities lead to pollution in the environment. Amongst many other pollutants, polycyclic aromatic hydrocarbons represent a major class of contaminants owing to their widespread distribution and protracted environmental persistence. No information is available about the levels of Polycyclic aromatic hydrocarbon (PAH) contamination in the sediments along the coastline of Goa. The study aimed to establish a baseline for PAH concentrations in the sediments along the shoreline to help comment on the pollution levels caused and thereby understand the risk and their impact on the marine life therein. The total concentration of PAHs along the selected sampling sites of the Goa coastline was 1.00 to 875 µg g-1. Maximum PAH concentrations were detected in the Divar island mangrove (875 µg g-1); the least was observed at Galgibaga beach (365 µg g-1). The results revealed that the sediment of the Goa coastline is heavily contaminated with PAH. Source apportionment of PAHs was analysed based on diagnostic ratios, and results exhibited that petroleum products and their combustion were primarily responsible for their generation. The results of risk quotients showed that the values are way above effect range median (ER-M), indicating these could pose a high risk to the ecosystem.

Folin-Ciocalteu assay as a rapid colourimetric screening method for evaluating PAH degradation abilities of heterotrophic bacteria.

Bioremediation using microbes is an eco-friendly approach being explored for reclaiming PAH-contaminated areas. However, isolation and screening of potential bacteria to degrade PAHs are very laborious and cumbersome. To alleviate this issue, we describe a rapid method for screening the bacterial cultures for their ability to degrade PAHs using Folin-Ciocalteu (FC) assay. Six hundred bacterial isolates were tested for their ability to degrade PAH using FC assay. The cultures capable of degrading PAH show blue colouration, resulting from the reaction of FC reagent with phenolic intermediates generated during PAH degradation. Out of the 600 cultures screened, 64 showed an ability to degrade PAH. This study provides a very easy, rapid, less laborious, and sensitive method to screen a large number of bacterial cultures for their ability to degrade PAH. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03549-4.

Recent work on vaginal rings containing antiviral agents for HIV prevention.

PURPOSE OF REVIEW: In response to the need for strategies women can use to protect themselves from HIV infection, a new class of product commonly referred to as vaginal 'microbicides' has been under development for the past few decades. Several leading products currently in development contain antiviral agents delivered in a vaginal ring. RECENT FINDINGS: Research published over the past year reports advances in identification and continued formulation of specific antiviral agents that have potential for delivery in vaginal rings, including drug combinations for HIV, other sexually transmitted infections and contraception. Most products are antiretroviral reverse transcriptase inhibitors. Advances in vaginal ring design have also been reported; some of these are designed to release specific antiviral agents, while other designs could be used for multiple drugs. This review focuses both on antiviral agents and vaginal ring designs. SUMMARY: Over the past year, advances continued to be made in the development of vaginal rings to deliver antiviral agents for prevention of HIV. An array of antiviral agents and vaginal ring designs to deliver these products are at various stages in the product pipeline process. Results from the first efficacy trials of an antiretroviral-containing vaginal ring are expected soon and will inform the continued development of this important product class.

Distribution of butyltins in the waters and sediments along the coast of India.

Water and surface sediment samples were analyzed for butyltins (TBT, DBT, MBT) from various ports along the east and west coast of India. The total butyltin (TB) in water samples varied between ~1.7 and 342 ng S nl⁻¹, whereas for sediments it varied between below detection limit to 14861 ng S ng⁻¹ dry weight of sediment. On an average Chennai port recorded the highest level of butyltins in the sediments while Paradip recorded the highest level of butylins in the waters. A fairly good relationship between the TB in the sediment and overlying water samples, as well as between organic carbon and TB, implicates the importance of adsorption/desorption process in controlling the levels of TBT in these port areas. In India the data on organotin pollution is very sparse; most of the port areas have been surveyed for butyltins for the first time during this study.

Distribution of butyltins in waters and sediments of the Mandovi and Zuari estuaries, west coast of India.

Butyltins (TBT, DBT, MBT) were measured in water and sediment samples collected from various locations in the Mandovi (ten stations) and Zuari (nine stations) estuaries during November 2007. The total butyltin (TB) in water samples varied between approximately 12 and 73 and from 0.5 to 77 ng Sn l(-1), whereas for the sediments, it varied from approximately 15 to 118 and 6 to 119 ng Sn g(-1) dry weight for the Mandovi and the Zuari estuaries, respectively. The average TB concentration in the sediments from the Zuari estuary was higher as compared to the Mandovi estuary, whereas for the water samples, it was vice versa. For both the water and sediment samples, MBT was generally the most predominant butyltin in these two estuaries. This suggests that the butyltin contamination was not freshly derived. Fairly good relationships between the concentrations of TB and organic carbon in water and sediment samples of these estuaries implicate the importance of adsorption/desorption processes in controlling the levels of TB in these estuaries.

Hepatic stellate cells express functional CXCR4: role in stromal cell-derived factor-1alpha-mediated stellate cell activation.

UNLABELLED: Chemokine interactions with their receptors have been implicated in hepatic stellate cell (HSC) activation. The hepatic expression of CXCR4 messenger RNA is increased in hepatitis C cirrhotic livers and plasma levels of its endogenous ligand, stromal cell-derived factor-1alpha (SDF-1alpha), correlate with increased fibrosis in these patients. The expression of CXCR4 by HSCs has not been reported. We therefore examined whether HSCs express CXCR4 in vivo and in vitro and explored whether SDF-1alpha/CXCR4 receptor engagement promotes HSC activation, fibrogenesis, and proliferation. The hepatic protein expression of both CXCR4 and SDF-1alpha is increased in hepatitis C cirrhotic livers and immunoflourescent and immunohistochemical staining confirms that HSCs express CXCR4 in vivo. Immortalized human stellate cells as well as primary human HSCs express CXCR4, and cell surface receptor expression increases with progressive culture-induced activation. Treatment of stellate cells with recombinant SDF-1alpha increases expression of alpha-smooth muscle actin and collagen I and stimulates a dose-dependent increase in HSC proliferation. Inhibitor studies suggest that SDF-1alpha/CXCR4-dependent extracellular signal-regulated kinase 1/2 and Akt phosphorylation mediate effects on collagen I expression and stellate cell proliferation. CONCLUSION: HSCs express CXCR4 receptor in vivo and in vitro. CXCR4 receptor activation by SDF-1alpha is profibrogenic through its effects on HSC activation, fibrogenesis, and proliferation. Extracellular signal-regulated kinase 1/2 and phosphoinositide 3-kinase pathways mediate SDF-1alpha-induced effects on HSC expression of collagen I and proliferation. The availability of small molecule inhibitors of CXCR4 make this receptor an appealing target for antifibrotic approaches.

The future of HIV microbicides: challenges and opportunities.

HIV microbicides are topical, self-administered products aimed at preventing or reducing HIV infection in women and may represent the most promising strategy for combating the HIV/AIDS epidemic at the present time. Although a safe and effective microbicide has yet to be identified, all products tested in Phase III trials to date have been vaginal gels containing non-specific compounds with modest potency that had to be applied close to the time of sexual intercourse. Issues regarding these early generation products were further complicated by widely publicized cases of halted efficacy trials. However, as a result of each of these challenges, new information and essential lessons have emerged for the field. These lessons have resulted in a meaningful increase in microbicide development efforts focusing on compounds with highly potent and HIV-specific mechanisms of action, combination products, novel formulations, and carefully designed pharmacokinetic and pharmacodynamic evaluations, all of which are reasons for renewed confidence that a safe and effective microbicide is achievable.

Seasonal variation in organotins in the waters of the Dona Paula Bay, west coast of India.

Surface seawaters from the Dona Paula Bay, were collected at weekly intervals during March 2007 to March 2008, and analyzed for butyltins (BT) such as tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT) using a GC-MS system. The mean concentrations of TBT, DBT, MBT and total BT varied from <1-37, 4-19, 6-28 and 21-84 ng Sn L(-1), respectively. Highest levels of BTs were recorded during May followed by April 2007 and March 2007 probably because the shipping and tourism activities are very high during these months.

Butyltins in the sediments of Kochi and Mumbai harbours, west coast of India.

Surface sediment samples were collected from various locations in the Mumbai and Kochi harbours, west coast of India, to assess the presence of butyltin compounds. Tributyltin (TBT) and dibutyltin (DBT) varied from 16 to 16,816 ng/g dry wt. and from undetected to 469 ng/g dry wt., respectively, of the sediment in Kochi harbour. In Mumbai harbour, the values of TBT and DBT ranged between 4.5 and 1193 ng/g dry wt. and from undetected to 131 ng/g dry wt. of the sediments, respectively. The concentrations of both TBT and DBT showed strong seasonal variation probably due to the effect of tides and currents. Nevertheless, the levels of butyltin compounds were generally higher at sites influenced by shipping activities such as navigation, dry dock and ship-building activities. The presence of DBT indicates the abiotic or microbiological degradation of TBT. Compared to TBT, DBT was relatively less abundant, suggesting either fresh inputs of TBT and/or less degradation of TBT. The concentrations of TBT showed significant positive relationships with organic carbon and lipid, implying that both lipophilic and ionic interactions were probably involved in controlling the abundance of TBT at these sediments. The observed levels of butyltin compounds are much higher than those required to induce toxic effects on marine organisms, suggesting that these sediments were contaminated with butyltin compounds.

Dynamics of amino acids in the conditioning film developed on glass panels immersed in the surface seawaters of Dona Paula Bay.

The conditioning film developed on glass panels immersed in surface seawater over a period of 24 h was analysed for total organic carbon (OC), total organic nitrogen (ON), and total hydrolyzable amino acid (THAA) concentrations and composition. The concentrations of C and N and THAA increased, whereas the C/N ratio decreased over the period of immersion. The amino acid-C and N accounted for 3.7-6.7% and 10.3-65.3% of OC and ON, respectively. The relative contribution of glycine plus threonine and serine to the total amino acids decreased while that of valine, phenylalanine, isoleucine and leucine increased over the period of immersion. Principal component analysis (PCA) based on mole% amino acid composition showed that the degradation indices (DI) for the conditioning film organic matter increased over the period of immersion. A high C/N ratio, a low %THAA-C, % THAA-N and DI values and the abundance of glycine plus threonine and serine in the conditioning film organic matter during the first few hours following immersion imply that the adsorbed organic matter was mostly derived from degraded organic matter.

Abundance of macroalgal organic matter in biofilms: evidence from n-alkane biomarkers.

Biofilm development on titanium panels immersed in the surface waters of Dona Paula Bay was investigated using molecular biomarkers such as n-alkanes and other chemical and biological parameters. Biofilm biomass measured as organic carbon (OC), organic nitrogen (ON), chlorophyll a, diatoms and bacterial numbers on the titanium panels generally increased over the period of immersion. Total lipids and n-alkane concentration also showed similar trends. n-alkanes from C(12) to C(30) were detected in the biofilm samples, which showed a bimodal distribution. The first mode consisted of n-alkanes > C(23) with a strong even over odd predominance. In the second mode, the n-alkanes < C(23) were more abundant with odd carbon number maxima at C(15), C(17) and C(19) and a strong odd over even carbon number predominance (Carbon Preference Index > 2). The predominance of these odd-chain n-alkanes strongly indicates that the organic matter derived from macroalgal sources was the major contributor to the biofilm organic matter developed on the titanium panels over the 15 d period of study. The data suggest that molecular characterization is a useful tool in understanding the sources of biofilm organic matter. The observed abundance of macroalgal organic matter during the 15 d period of biofilm development may play an important role in subsequent fouling by micro- and macrofouling organisms.

Butyltins in water, biofilm, animals and sediments of the west coast of India.

Biofilm, fish, oyster, mussel, clam, surface seawater, suspended particulate matter (SPM), and sediment samples were collected from marine and/or estuarine waters of the west coast of India. These samples were analysed for butyltin derivatives such as dibutyltin (DBT) and tributyltin (TBT). The concentrations DBT plus TBT varied between 2.4 and 8.3, 163 and 363 ng/l, 5 and 2853 ng/g dry wt in the SPM, seawater and sediment samples, respectively, of the Marmugao harbour. The values of DBT plus TBT ranged between 0.60 and 29, 123 and 242 ng/l and 1.4 and 65 ng/g dry wt in SPM, water and sediment samples, respectively, collected from the Mandovi estuary. In the Dona Paula Bay the DBT plus TBT varied from 10 to 89 ng/l in surface seawater, and TBT from 10 to 513 ng/g in biofilm samples. For the coastal sediment samples the concentration of DBT plus TBT ranged between 36 and 133 ng/g dry wt of sediment. For the animal samples the DBT plus TBT ranged between 58 and 825 ng/g dry wt of the tissue. Mussel tissues contained the highest amount of DBT plus TBT (825 ng/g dry wt tissue), whereas highest TBT concentration was recorded in the oyster (732 ng/g dry wt). TBT was generally the most abundant butyltin compound in most of the samples suggesting fresh inputs and/or less degradation of TBT. A wide range of the observed butyltin concentrations suggests the presence of localized areas of contamination. Leaching of tributyltin-containing antifouling paints from the ocean going ships, fishing and recreational boats, barges, and the inputs of TBT from the Goa shipyard and dry dock facility situated in the harbour are the probable sources of the DBT and TBT in the samples of the west coast of India. Higher levels of TBT were observed in biofilm relative to that in the surrounding seawater. When fed on TBT contaminated biofilm of the diatom Navicula subinflata, butyltin concentrations in the clam Paphia malabarica increased over the period of feeding suggesting the importance of biofilm in the transfer of butyltins to higher group of organisms.