Deciphering carbon dioxide fluxes and interactions in the Ganga river Basin of South Asia.

Anthropogenic influences significantly modify the hydrochemical properties and material flow in riverine ecosystems across Asia, potentially accounting for 40-50% of global emissions. Despite the pervasive impact on Asian rivers, there is a paucity of studies investigating their correlation with carbon dioxide (CO2) emissions. In this study, we computed the partial pressure of CO2 (pCO2) using the carbonate equilibria-based model (pCO2SYS) and examined its correlation with hydrochemical parameters from historical records at 91 stations spanning 2013-2021 in the Ganga River. The investigation unveiled substantial spatial heterogeneity in the pCO2 across the Ganga River. The pCO2 concentration varied from 1321.76 µatm, 1130.98 µatm, and 1174.33 µatm in the upper, middle, and lower stretch, respectively, with a mean of 1185.29 µatm. Interestingly, the upper stretch exhibited elevated mean pCO2 and FCO2 levels (fugacity of CO2: 3.63 gm2d-1) compared to the middle and lower stretch, underscoring the intricate interplay between hydrochemistry and CO2 dynamics. In the context of pCO2 fluctuations, nitrate concentrations in the upper segment and levels of biological oxygen demand (BOD) and dissolved oxygen (DO) in the middle and lower segments are emerging as crucial explanatory factors. Furthermore, regression tree (RT) and importance analyses pinpointed biochemical oxygen demand (BOD) as the paramount factor influencing pCO2 variations across the Ganga River (n = 91). A robust negative correlation between BOD and FCO2 was also observed. The distinct longitudinal patterns of both parameters may induce a negative correlation between BOD and pCO2. Therefore, comprehensive studies are necessitated to decipher the underlying mechanisms governing this relationship. The present insights are instrumental in comprehending the potential of CO2 emissions in the Ganga River and facilitating riverine restoration and management. Our findings underscore the significance of incorporating South Asian rivers in the evaluation of the global carbon budget.

School resource inadequacy and school social engagement: Mediating effect of principals' stress.

This study is intended to assess and help us understand the role of school resource inadequacy (SRI) on school social engagement (SSE). The authors also utilize this opportunity to analyze the influence of school resource inadequacies on principal stress (PS) and the influence of PS on SSE. School administrators would stand to benefit by understanding the direct influences of school resource inadequacies on SSE, the direct influence of school resource inadequacies on PS, the direct influence of PS on SSE, and the interactional effect of school resource inadequacies and PS on SSE. This study utilizes data from the "Teaching and Learning International Survey (TALIS) Principal Questionnaire," 2018 available for England (United Kingdom). The respondents for this survey are principals of public and private schools in England (United Kingdom). Cronbach alpha values were calculated for the variables to confirm the reliability of variables considered for this study. Also used in this study are the Kaiser-Meyer-Olkin (KMO) test and the Andrew F. Hayes model 4 to test the mediating influence and interactional effects. SPSS 23.0 was used for the purpose of data analysis and the output tables are from the results of the tests done using SPSS. The results reiterate the relationship between SRI and PS. This study also establishes the relationship between PS and SSE as being negative, meaning that the lower the PS greater is the SSE. Results also show evidence of the relationship between SRI and SSE, meaning that adequate school resources have a positive influence on SSE. Further, the mediating effect of PS on SSE and SRI was also tested and established. The findings of this study are important for school administrators and regulators in understanding the relationship between school resources, SSE, and the mediating influence of PS. This study establishes the relationship between SRI and PS, SRI and SSE, PS, and SSE. The research is also unique as it establishes the mediating influence of PS.

Impact of microplastics on riverine greenhouse gas emissions: a view point.

In recent decades, microplastics (MPs < 5 mm) are ubiquitous and considered a serious emerging environmental problem. However, due to the limited recovery and long-lasting durability MPs, debris is frequently accumulating in riverine ecosystems, thereby impacting microbial activity and its communities. The presence of MPs may alter the microbial richness, variety, and population, thereby impacting the transformation of biogeochemical cycles. The occurrence, fate, and transport of MPs in marine and terrestrial ecosystems and their impact on biogeochemical or nutrient cycling are reported in the scientific fraternity. Yet, the global scientific community is conspicuously devoid of research on impact of MPs on riverine greenhouse gas (GHG) emissions. The presented view point provides a novel idea about the fate of MPs in the riverine system and its impact on GHG emissions potential. Literature reveals that DO and nutrients (organic carbon, NH4+, NO3-) concentrations play an important role in potential of GHG emission in riverine ecosystems. The proposed mechanism and research gaps provided will be highly helpful to the hydrologist, environmentalist, biotechnologist, and policymakers to think about the strategic mitigation measure to resolve the future climatic risk.

Accessory enzymes of hypercellulolytic Penicillium funiculosum facilitate complete saccharification of sugarcane bagasse.

BACKGROUND: Sugarcane bagasse (SCB) is an abundant feedstock for second-generation bioethanol production. This complex biomass requires an array of carbohydrate active enzymes (CAZymes), mostly from filamentous fungi, for its deconstruction to monomeric sugars for the production of value-added fuels and chemicals. In this study, we evaluated the repertoire of proteins in the secretome of a catabolite repressor-deficient strain of Penicillium funiculosum, PfMig188, in response to SCB induction and examined their role in the saccharification of SCB. RESULTS: A systematic approach was developed for the cultivation of the fungus with the aim of producing and understanding arrays of enzymes tailored for saccharification of SCB. To achieve this, the fungus was grown in media supplemented with different concentrations of pretreated SCB (0-45 g/L). The profile of secreted proteins was characterized by enzyme activity assays and liquid chromatography-tandem mass spectrometry (LC-MS/MS). A total of 280 proteins were identified in the secretome of PfMig188, 46% of them being clearly identified as CAZymes. Modulation of the cultivation media with SCB up to 15 g/L led to sequential enhancement in the secretion of hemicellulases and cell wall-modifying enzymes, including endo-ß-1,3(4)-glucanase (GH16), endo-α-1,3-glucanase (GH71), xylanase (GH30), ß-xylosidase (GH5), ß-1,3-galactosidase (GH43) and cutinase (CE5). There was ~ 122% and 60% increases in ß-xylosidase and cutinase activities, respectively. There was also a 36% increase in activities towards mixed-linked glucans. Induction of these enzymes in the secretome improved the saccharification performance to 98% (~ 20% increase over control), suggesting their synergy with core cellulases in accessing the recalcitrant region of SCB. CONCLUSION: Our findings provide an insight into the enzyme system of PfMig188 for degradation of complex biomass such as SCB and highlight the importance of adding SCB to the culture medium to optimize the secretion of enzymes specific for the saccharification of sugarcane bagasse.

Chemical profiling and quantification of potential active constituents responsible for the antiplasmodial activity of Cissampelos pareira.

ETHNOPHARMACOLOGICAL RELEVANCE: Cissampelos pareira is used traditionally in India as a remedy for the treatment of various diseases including malaria but the active ingredients responsible for antiplasmodial activity have not yet been investigated. AIM OF THE STUDY: The identification and quantification of compounds responsible for antiplasmodial activity in different parts (leaf, stem and root) of C. pareira is the target of current study. MATERIAL AND METHODS: The hydro ethanolic parent extracts of different parts of C. pareira and fractions prepared from these extracts were evaluated against Pf3D7 (chloroquine sensitive) and PfINDO (chloroquine resistance) strains in culture to quantify the IC50 for extracts and fractions. Promising fractions of root part of plant were subjected to silica gel column chromatography to obtain pure compounds and their structures were elucidated by detailed spectroscopic analysis. Pure compounds were also tested against Pf3D7 and PfINDO strains. A rapid and simple UPLC-DAD method was developed for the identification and quantification of pharmaceutically important metabolites of C. pareira. RESULTS: Among different extracts, the hydro ethanolic extract of root part of C. pareira was found most active with IC50 values (µg/ml) of 1.42 and 1.15 against Pf 3D7 and Pf INDO, respectively. Tested against Pf 3D7 the most potent fractions were root ethyl acetate fraction (IC50 4.0 µg/ml), stem water fraction (IC50 4.4 µg/ml), and root water fraction (IC50 8.5 µg/ml). Further, phytochemical investigation of active fractions of root part led to the isolation and characterization of a new isoquinoline alkaloid, namely pareirarine (8), along with five known compounds magnoflorine (5), magnocurarine (10), salutaridine (11), cissamine (13) and hayatinine (15). Hayatinine (15), a bisbenzylisoquinoline alkaloid, isolated from root ethyl acetate fraction was most promising compound with IC50 of 0.41 µM (Pf INDO) and 0.509 µM (Pf 3D7). Magnocurarine (10) and cissamine (13) were also found active with IC50 values of 12.51 and 47.34 µM against Pf INDO and 12.54 and 8.76 µM against Pf 3D7, respectively. A total of thirty compounds were detected in studied extracts and fractions, structures were assigned to 15 of these and five of these biologically important compounds were quantified. Isolation of saluteridine (11) from C. pareira and the evaluation of antiplasmodial activity of pure compound from C. pariera is disclosed for the first time. CONCLUSION: This study concludes that the antimalarial potential of C. pareira may be attributed to isoquinoline type alkaloids present in this plant and also provides the scientific evidence for the traditional use of this plant in treatment of malaria.

Evaluation of Antiplasmodial Potential of C2 and C8 Modified Quinolines: in vitro and in silico Study.

BACKGROUND: Malaria remains a common life-threatening infectious disease across the globe due to the development of resistance by Plasmodium parasite against most antimalarial drugs. The situation demands new and effective drug candidates against Plasmodium. OBJECTIVES: The objective of this study is to design, synthesize and test novel quinoline based molecules against the malaria parasite. METHODS: C2 and C8 modified quinoline analogs obtained via C-H bond functionalization approach were synthesized and evaluated for inhibition of growth of P. falciparum grown in human red blood cells using SYBR Green microtiter plate based screening. Computational molecular docking studies were carried out with top fourteen molecules using Autodoc software. RESULTS: The biological evaluation results revealed good activity of quinoline-8-acrylate 3f (IC50 14.2 µM), and the 2-quinoline-α-hydroxypropionates 4b (IC50 6.5 µM), 4j (IC50 5.5 µM) and 4g (IC50 9.5 µM), against chloroquine sensitive Pf3D7 strain. Top fourteen molecules were screened also against chloroquine resistant Pf INDO strain and the observed resistant indices were found to lie between 1 and 7.58. Computational molecular docking studies indicated a unique mode of binding of these quinolines to Falcipain-2 and heme moiety, indicating these to be the probable targets of their antiplasmodial action. CONCLUSION: An important finding of our work is the fact that unlike Chloroquine which shows a resistance Index of 15, the resistance indices for the most promising molecules studied by us were about one indicating equal potency against drug sensitive and resistant strains of the malaria parasite.

Rh(III)-Catalyzed C(8)-H Functionalization of Quinolines via Simultaneous C-C and C-O Bond Formation: Direct Synthesis of Quinoline Derivatives with Antiplasmodial Potential.

Here, a facile and efficient protocol for the synthesis of 3-hydroxyquinolin-8-yl propanoates via Rh(III)-catalyzed C(8)-H activation of 2-substituted quinolines has been developed. The reaction proceeds via C(8)-H activation, functionalization with acrylates, followed by intramolecular migration of the oxygen atom from quinoline N-oxides to the acrylate moiety. In this approach, N-oxide plays a dual role of a traceless directing group as well as a source of an oxygen atom for hydroxylation. This catalytic method involves simultaneous formation of new C-C and C-O bonds and is applicable only for C2-substituted quinolines. A catalytically competent five-membered rhodacycle has been characterized, thus revealing a key intermediate in the catalytic cycle. In silico docking studies against Falcipan-2 have revealed that 3a, 3b, 3g, and 3m have better scores. In vitro evaluation of selected compounds against CQ-sensitive pf3D7 and CQ-resistant pfINDO strains provided evidence that 3d (IC50 13.3 µM) and 3g (IC50 9.5 µM) had good promise against Plasmodium falciparum in the in vitro culture. Compound 3g was found to be the most potent on the basis of both in vitro antiplasmodial activity [IC50 9.5 µM ( Pf3D7) and 11.9 µM ( PfINDO), resistance index 1.25] and in silico studies.

Catalyst and Additive-Free Diastereoselective 1,3-Dipolar Cycloaddition of Quinolinium Imides with Olefins, Maleimides, and Benzynes: Direct Access to Fused N,N'-Heterocycles with Promising Activity against a Drug-Resistant Malaria Parasite.

A convenient and eco-friendly synthesis of various fused N-heterocyclic compounds through catalyst and additive-free 1,3 dipolar cycloadditions of quinolinium imides with olefins, maleimides, and benzynes in excellent yields and diastereoselectivities is reported. The thermally controlled diastereoselective [3 + 2] cycloaddition reaction between quinolinium imides and olefins provided cis-isomers at low temperature and trans-isomers at high temperature. A reaction between quinolinium imides with substituted maleimides gave four-ring-fused N-heterocyclic compounds in high yields as a single diastereomer. The aryne precursors also provided four-ring-fused N,N'-heterocyclic compounds in high yields. The in vitro antiplasmodial activity of selected molecules revealed that this class of molecules possesses potential for ongoing studies against malaria.

Bioprospecting and biotechnological applications of fungal laccase.

Laccase belongs to a small group of enzymes called the blue multicopper oxidases, having the potential ability of oxidation. It belongs to enzymes, which have innate properties of reactive radical production, but its utilization in many fields has been ignored because of its unavailability in the commercial field. There are diverse sources of laccase producing organisms like bacteria, fungi and plants. In fungi, laccase is present in Ascomycetes, Deuteromycetes, Basidiomycetes and is particularly abundant in many white-rot fungi that degrade lignin. Laccases can degrade both phenolic and non-phenolic compounds. They also have the ability to detoxify a range of environmental pollutants. Due to their property to detoxify a range of pollutants, they have been used for several purposes in many industries including paper, pulp, textile and petrochemical industries. Some other application of laccase includes in food processing industry, medical and health care. Recently, laccase has found applications in other fields such as in the design of biosensors and nanotechnology. The present review provides an overview of biological functions of laccase, its mechanism of action, laccase mediator system, and various biotechnological applications of laccase obtained from endophytic fungi.