Sub-Himalayan West Bengal Research Articles

In silico, in vitro, and in vivo acute and sub-acute toxicity profiling of whole plant methanol extract of Equisetum diffusum D. Don from the sub-Himalayan West Bengal, India, having ethnobotanical uses

BackgroundEquisetum diffusum D. Don commonly known as ‘Himalayan horsetail’, has been traditionally used in the treatment of back pain, bone fracture and dislocation, and arthritis by various tribal communities of India. Our previous study confirmed the anti-inflammatory efficacy of the plant through in silico, in vitro, and in vivo model studies. Therefore, the current research is focused on safety dose evaluation for the first-time of the whole-plant methanol extract (EDME) of E. diffusum through appropriate in silico, in vitro, and in vivo approaches.MethodThe whole plant, along with its rhizomes, was collected, and the methanol extract was prepared. The in silico ADMET study was performed to predict the pharmacokinetics profile and toxicity of all the identified phyto-compounds of EDME previously screened by GC–MS study. In vitro cytotoxicity study of EDME was performed using two cell lines: kidney (HEK293) and liver (Huh7) cell lines. The in vivo toxicity study of EDME was validated by the acute toxicity (OECD 423, 2002) and sub-acute toxicity assays (OECD 407, 2008) in the Wistar Albino rat model.ResultsThe in silico ADMET study of all 47 bioactives predicted good pharmacokinetic and low toxicity profiles. In vitro cytotoxicity showed higher IC50 values of EDME viz., 672 ± 15.7 μg/mL and 1698 ± 6.54 μg/mL for both kidney (HEK293) and liver (Huh7) cell lines, respectively, which were considered as low-toxic. Based on acute oral toxicity, the LD50 value of the extract was considered “non-toxic” up to a feeding range of 2000 mg/kg of body weight. The regular consumption of the extract for an extended period (28 days) was also qualified as safe based on the body and organ weight, hematological, biochemical, and histoarchitecture results in the sub-acute toxicity assay.ConclusionThe detailed in silico, in vitro, in vivo (acute and sub-acute oral toxicity) studies gave us a new insight to the safety dose evaluation of Equisetum diffusum, which may serve as a reliable documentation for undertaking the experimental validation of the ethnobotanical uses of the plant which would help in the field of drug development for the treatment of inflammation related complications.

Neurological potency of native plants from sub-Himalayan West Bengal through reverse pharmacology

Neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), and epilepsy, pose a growing global health challenge due to an aging population. These conditions share common processes, including protein accumulation, oxidative stress, and neuro-inflammation, making their treatment complex and costly. Network pharmacology, an innovative approach integrating systems biology and computational biology, offers insights into multi-target formulations and the repurposing of existing medications for neurodegenerative diseases. We shortlisted 730 bioactive compounds from 25 traditional Himalayan plants, assessed their drug-like properties using ADME criteria, and predicted their potential target proteins through reverse docking and pharmacophore mapping. Our study identified 287 compounds with high gastrointestinal absorption and good blood-brain barrier permeability. These compounds were subjected to target prediction, yielding a list of 171 potential target proteins. Functional annotation and pathway enrichment analysis highlighted their involvement in steroid hormone-related pathways, MAPK signaling, FOXO signaling, TNF signaling, VEGF signaling, and neurotrophin signaling. Importantly, one plant, Valeriana jatamansi, exhibited an association with beta-amyloid binding activity, a potential therapeutic approach for AD. From our study we could understand how these plants modulate our body to manage these diseases. However, further in vitro and in vivo validation is needed before commercial and public use of this data.

Unraveling the dynamics of climate: empirical evidence from the Indian state of West Bengal

Abstract Understanding climate variability and trends is crucial for managing a host of sectors. Everything from water availability to agricultural productivity is affected by variability and trends in temperature, rainfall, evapotranspiration, and solar radiation. Nevertheless, their dynamics have seldom been explored together, especially in India. To address this gap, the present study investigates the variability, trend, and magnitude of those parameters individually and concurrently using fractal dimension and non-parametric statistics over the Indian state of West Bengal from 1951 to 2020. The results show a south–north gradient in overall climate variability. The Gangetic West Bengal (GWB) is experiencing higher variability, along with a rising minimum temperature (≥0.008 °C year−1) and declining rainfall (≥− 1 mm year−1). Though the Sub-Himalayan West Bengal as a whole shows less variability, its foothills reveal modest variation coupled with increasing maximum temperature (≥0.005 °C year−1), reference evapotranspiration (≥0.4 mm year−1), and decreasing rainfall in the post-monsoon and winter seasons. Based on the results, we identified the western GWB, the Sundarbans, and the sub-Himalayan foothills as the most vulnerable areas and recommended proactive crop and water management strategies. Finally, we underline the need to analyze climate dynamics holistically to manage climate-sensitive sectors efficiently and sustainably.

Resistance status and activity of detoxifying enzymes in Oligonychus coffeae (Nietner)(Acari:Tetranychidae) on tea

Regular monitoring of acaricide resistance in economically important plant feeding mites is important for effective management. Oligonychus coffeae is one of the most important mite pests of tea and acaricides are frequently used to manage this pest, yet control failures sometimes occur at recommended doses. Hence, bioassay experiments were conducted to confirm whether such control failures were caused by resistance development in populations collected from major tea growing areas of Sub-Himalayan West Bengal, India. The adult females of O. coffeae were bio-assayed with commonly used six acaricides viz., dicofol, ethion, fenpropathrin, fenpyroximate, fenazaquin and propargite. Moreover, we estimated the activity of general esterase (GE), glutathione S-transferase (GST) and cytochrome P450 monooxygenase in the field collected samples as well as laboratory reared susceptible population. Based on the LC50 values, the resistance ratio of the field collected populations compared to the laboratory reared susceptible population varied from 3.29 to 5.85-fold,4.13–11.21-fold,12.07–28.28-fold,1.19–1.67-fold,1.12–1.77-fold, 2.73–5.34-fold for dicofol, ethion, fenpropathrin, fenpyroximate, fenazaquin and propargite, respectively. General esterase, GST and MFO activities of the tested populations were in the ranges of 5.69–16.54 mOD/min/mg protein, 91.51–319.91 μM/min/mg protein and 0.040–0.071 mOD/min/mg protein, respectively. The highest enzyme activity was detected in the Naxalbari population which was one of the most resistant populations to all the tested acaricides. The findings will be useful to the tea industry for selection of most effective chemical for successful management of this pest. Use of fenpropathrin and ethion should be discontinued for tea pest management and use of other chemicals having different mode of actions may be continued with rotation.

Quality of Life and Associated Determinants among Female Tea Garden Workers of Indigenous Communities in Sub-Himalayan West Bengal, India: A Cross- Sectional Mixed Methods

The purpose of this study was to examine the self-perceived quality of life (QOL) using World Health Organization quality of life (WHOQOL-BREF) instrument and associated controlling factors among socio-economically marginalized tribal female tea garden (TG) workers. A cross-sectional mixed-method research design involving both quantitative and qualitative techniques was employed on 378 study samples (18–60 years tribal female TG workers) between February and May 2022 across 10 TGs of Sub-Himalayan north Bengal, India. For the study, both summary statistics (mean, median, mode, standard deviation, and percentage distribution) and inferential statistics (Welch’s ANOVA, independent t-test, paired t-test and multivariate regression) were used to understand the dynamics of QOL and respondents narratives were facilitated to investigate the corresponding phenomenal scenario. Results: Findings indicate the QOL of the tribal female workers variably associated with different socioeconomic conditions and subjective well-being. The findings recommend that female tribal TG workers were perceived to have good ‘overall quality of life’ with a response rate of 33.1%, whereas more than 20% of participants respond that they were poor QOL on ‘overall quality of life’ and ‘general health’ items. The findings show lower summary statistics for most items in the environmental domain. Additionally, the study constructs a multivariate model that identifies several factors including socio-economy, neighbourhood, social relation, and others were significantly control the QOL of the study subjects. These outcomes may have important implications for future studies employing WHOQOL-BREF or similar instruments on different communities with distinctive sociocultural characteristics.

Unravelling the influence of teleconnection patterns on monsoon extreme precipitation indices over the Sikkim Himalayas and West Bengal

The influence of major climate indices of tropical seas and equatorial oceans on the variability of monsoon (June to September) extreme precipitation indices (EPIs) is explored for observed (1961–2017) period over two meteorological subdivisions of India. The strength and span of covariate relations for each EPI and the Indian Ocean Dipole (IOD), the Multivariate El Niño-Southern Oscillation Index (MEI), the Pacific Decadal Oscillation (PDO), the Southern Oscillation Index (SOI), and sea surface temperature (SST) anomaly of the Bay of Bengal (SST-BoB) as well as the Arabian Sea (SST-AS) are evaluated by linear and nonlinear functions. The periodicities and coherent patterns of each EPI and the climate indices are investigated in time–frequency space using wavelet power spectra. This is to identify the periodic behaviour, strength of nonlinear linkages and major climatic factors involved in the variability of monsoon precipitation extremes. EPIs show significant negative association for MEI and SST-AS. Consecutive dry days (CDD) develop significant positive (negative) correlation with MEI (SST-BoB) over Bihar, GWB, Orissa, Jharkhand and Sub-Himalayan West Bengal (SWB). The duration, intensity and absolute indices over the Sikkim (SIK) Himalayas exhibit significant negative correlation with the SST-BoB. The EPIs develop significant positive relation with PDO phases across the regions. EPIs show asymmetric correlation pattern for SST-BoB and SST-AS with the changes in latitudes and altitudes. Interannual periodic bands from low to medium frequency regions are observed in EPIs. CDD shows in-phase coherency with MEI, and a complex periodic oscillation with SST-BoB. Consecutive wet days (CWD) develop strong consistent decadal coherency with IOD. Monsoon total precipitation (PRCPTOT) is dominantly influenced by MEI and SST-BoB. Heavy precipitation events show strong response to the MEI and SST-AS over GWB. Absolute indices show regional variability in power spectra with intermittent breaks. For absolute indices, major controlling factors considerably vary at both subdivisions and timescales. This study reveals corresponding changes in active- and break-spells, drought and flood events, regional availability of water resources and its possible consequences.

Future changes in monsoon extreme climate indices over the Sikkim Himalayas and West Bengal

Utilizing an ensemble of regional climate models (RCMs) from Coordinated Regional Climate Downscaling Experiment (CORDEX) South Asia, projected changes in mean and extreme climate indices are analysed for future period (SCEN; 2021–2060). The parametric transformation bias correction technique is applied to enhance the model agreement in calibration period (1961–2005) and to produce reliable results for evaluation period. The observed pattern of temperature and precipitation indices is illustrated for control period (CTRL; 1961–2005), which exhibits high spatial variability with the altitudinal differences, especially over the Himalayas. Strong meridional moisture flow from the Bay of Bengal contributes higher, heavier and more intense precipitation events over the Sikkim Himalayas and northern Sub-Himalayan West Bengal (SWB). Despite spatial difference in the occurrences of return value for 5-, 10- and 50-year levels, some indices show close similarity between the Sikkim Himalayas and Gangetic West Bengal (GWB). The projected uncertainties under the RCPs remain very high for extreme temperatures over the Himalayas. Change in minimum temperature is largely significant. Conversely, maximum temperature shows insignificant change. Diurnal temperature range shows an expected decline for projected scenarios. Lower atmospheric easterlies towards east-central India enhance future moisture transport, which don’t eventually bring positive change for precipitation amount. Instead, the Sikkim Himalayas and the Eastern Ghats exhibit expected rise in higher, heavier and intense precipitation events. Consecutive dry days exhibit significant future rise over the plain and lower plateaus, which show significant decline over the mountains. The topographic forcings to the convective mechanism as well as model sensitivity evidently control the spatial pattern and occurrences of extreme events. Future rise in moisture level is more conspicuous under RCP8.5 along with the significant changes in extreme climate indices.

Detection of Virulence-Associated Genes and in vitro Gene Transfer From Aeromonas sp. Isolated From Aquatic Environments of Sub-himalayan West Bengal.

Aeromonas is omnipresent in aquatic environments and cause disease within a wide host range. A total of thirty-four isolates from water samples of small fish farms were identified as Aeromonas based on biochemical characteristics and 16S rRNA gene sequence. A total of six virulent factors were analyzed which indicated 100% of isolates as beta-haemolytic and proteolytic, whereas 44.1, 38.2, and 70.6% of isolates produced DNAse, siderophore, and amylase, respectively. Studies on the occurrence of four genetic determinants of virulence factors revealed that aer/haem (haemolytic toxin) and flaA (polar flagella) genes were present in 44.1% of strains whereas ascV (type 3 secretion system) and aspA (serine protease) genes were detected in 21.5 and 8.82% of strains, respectively. Fish (Anabas testudineus) challenge studies showed that the isolate GP3 (Aeromonas veronii) bearing five virulent factors with the combination of aer/haem+/ascV+/fla+ genes induced severe lesions leading to 100% of mortality. In contrast, RB7 possessing four virulence factors and three genes (aer/haem+/ascV+/aspA+) could not produce severe lesions and any mortality indicating the absence of correlation between the virulence factors, its genes, and the pathogenicity in fishes. GP3 was cytotoxic to human liver cell line (WRL-68) in trypan blue dye exclusion assay. The 431 bp aer/haem gene of GP3 was transferable to E. coli Dh5α with a conjugational efficiency of 0.394 × 10–4 transconjugants per recipient cell. The transfer was confirmed by PCR and by the presence of 23-kb plasmids in both donor and transconjugants. Therefore, the occurrence of mobile genetic elements bearing virulence-associated genes in Aeromonas indicates the need for periodic monitoring of the aquatic habitat to prevent disease outbreaks.

Do farmers perceive climate change clearly? An analysis of meteorological data and farmers’ perceptions in the sub-Himalayan West Bengal, India

AbstractFarmers must clearly perceive climate change to implement autonomous adaptations and support planned adaptation and mitigation initiatives. Based on the primary data collected from 300 farming households of the sub-Himalayan West Bengal of India, the present study compared farmers’ perceptions with meteorological trends obtained through a combination of statistical and graphical tests. Many farmers declared a change in local climate, and farmers’ perceptions mostly cognate the increasing summer temperature and decreasing monsoon precipitation from 1991 to 2020. However, a greater level of imperfect perceptions was observed for the winter temperature rise. Overall, only 23% of farmers were able to clearly perceive all the changes in climatic conditions. A binary logistic regression model was employed to identify the determining factors of farmers’ clear perceptions, and results showed that farmers who are younger, male, read newspapers, and experienced elephant crop-raiding perceived the changes more accurately. Whereas access to television and irrigation facilities decreased the probability of perceiving climate change accurately. The study recommends that bridging the knowledge gap between farmers and stakeholders is necessary for this region, which could be achieved by disseminating accurate weather information in combination with agricultural advice and targeted initiatives, especially for the older and female farmers.

Multidimensional Rural Livelihoods in Indian Sub-Himalaya: Regional Analysis, Households Well-Being and Its Determinants

A cursory review of literatures shows a void in regional patterns analysis of rural livelihood in the sub-Himalayan West Bengal, India. Therefore, this study has attempted to examine the regional pattern of multidimensional rural livelihoods (assets, accessibility, health and education) in the study area. The study has attempted to look at the various determinants that make a region different from others in the same geographical space in terms of livelihood practices and household well-being. The study has applied a mixed research method, that is, Principal component analysis (PCA), household well-being indicator approach, multiple regressions, and focus group discussions (FGDs). The community blocks of the study area are found to be differently endowed in terms of different assets. The results show that marginalised castes and non-Hindu households have a relatively lower well-being score than the other households. The results suggest that daily work opportunities and an increase in the number of casual labourers positively impact the generation of decent and sustainable livelihood. It also shows an increase in the household well-being score to occupation groups such as businesses and salaried jobs. However, collection of sandstone and other construction materials from the river bed is emerging as a new source of livelihood.

Heavy rainfall analysis over Teesta catchment and adjoining areas of Sub-Himalayan West Bengal and Sikkim

Heavy rainfall (HRF) forecasting in hilly region is always a challenge to the operational forecasters. Synoptic Analogue Model (SAM) is considered as one of the useful tools for HRF forecasting in topographically influenced hilly regions. In every monsoon season, the Teesta river catchment and its adjoining areas in Sub-Himalayan West Bengal and Sikkim (SHWB-S) generally receive several events of HRF. With the primary objective to find the method to issue HRF warning over Teesta river catchment and adjoining areas in SHWB-S, a SAM has been developed by analyzing 18 years (1998-2015) data comprising prevailing synoptic situations affecting the area and daily rainfall data of subsequent day of HRF. In addition, impact of different synoptic systems on the distribution of HRF has also been studied. The results revealed that there exists a good agreement between daily HRF warnings issued with the corresponding HRF event observed over this region on the next day.

What caused smallholders to change farming practices in the era of climate change? Empirical evidence from Sub-Himalayan West Bengal, India

What caused smallholders to change farming practices in the era of climate change? Empirical evidence from Sub-Himalayan West Bengal, India

Forecasting monthly rainfall of Sub-Himalayan region of India using parametric and non-parametric modelling approaches

Rainfall being a complex phenomenon governed by various meteorological parameters is difficult to model and forecast with high precision. For hilly regions such as state of Sikkim and adjoining areas of West Bengal, rainfall acts as lifeline. Several parametric models such as seasonal autoregressive integrated moving average (SARIMA) and exponential autoregressive (EXPAR) are very popular and extensively used to model and forecast rainfall. Owning to complex nature of rainfall series, non-parametric time delay neural network (TDNN) model has also gained substantial amount of attention by researchers. This study uses these two broad class of models and applies them to the monthly rainfall of Sub-Himalayan West Bengal and Sikkim. The models were compared based on their forecasting efficiencies and pattern prediction ability.

Study on Spikelet Morphology of Some Indian Grasses (Poaceae)

Poaceae (Graminae) is the most species-rich vascular flowering plant family that includes many economically valuable food crops consumed by human beings in different parts of the World. Grasses are most common floral component of all kind of vegetation and they grow in marshy lowland to higher altitude i.e., subalpine to alpine environment. Identification at the species level becomes extremely difficult in grasses and only the revelation of detailed spikelet structures can only provide a satisfactory result. Present work studied detailed morphology of various parts of spikelet of some grass from sub-Himalayan West Bengal along with their suitable illustrations.

HLA-A -B and -DRB1 distribution in Kami: A caste population of Gorkha community from the sub-Himalayan region of West Bengal, India

The present investigation is the first of its kind to understand the HLA profile of Kami population from the Indian Gorkha community of sub-Himalayan West Bengal, India. A total of 158 individuals from Kami population were genotyped at first field resolution by HLA ABDRB1 PCR SSP typing kit. The genotype assignment to the individuals was performed by Ready Gene V.1.0.0.0′ software. The data were analysed by PopWin32-0.7.0 software. All the loci typed were in Hardy-Weinberg equilibrium. The genotype data is accessible at Allele Frequencies Net Database with the name India, sub-Himalayan West Bengal, Kami number 3720.

Determinants of household livelihood vulnerabilities to climate change in the himalayan foothills of West Bengal, India

The impact of climate change and variability on household livelihood in the Himalayan region is hardly studied due to their locational inaccessibility. Therefore, the aim of the present study is to determine the factors which affect rural household vulnerability in sub-Himalayan West Bengal, India. How the socio-economic conditions of the households and climate change have been affecting the overall livelihood of this region? To understand the determining factors of household livelihood vulnerabilities, four main domains of vulnerabilities have been considered, namely, ‘income loss’, ‘crop loss’, ‘housing loss’, and ‘overall livelihood loss’ due to climate changes. The study has applied ordinal logistic regression along with focus group discussion to find out the determining factors. The survey data shows that specific variables such as the size of agricultural land, occupation of the households' heads, caste, membership of self-help groups, and perception of precipitation trends are the main determining factors of income loss in maximum households. Moreover, housing type, mainly non-concrete and semi-concrete houses are responsible for household vulnerability to climate change. Every household of this region loses a significant amount of crop due to the heavy rainfall or floods; although several households have adopted new resilient crop varieties. Nevertheless, crop loss is a major climatic threat in the sub-Himalayan region of West Bengal. Further, the results of the present study also suggest that the low adaptive capacity of the rural households of this region, such as low-income opportunities and inadequate infrastructure are the primarily reasons for most livelihood vulnerabilities.

Assessing the Status of Changing Channel Regimes of Balason and Mahananda River in the Sub-Himalayan West Bengal, India

Rapid infrastructural development, triggered by the economic policies implemented in 1991, subsequently modified the river channel planform of the Terai region of northern West Bengal, India, through perceptible channel fragmentation, excessive in-channel sediment mining and rampant landuse alterations of the floodplains. In this context, this study has attempted to assess the impacts of anthropogenic interventions on fluvial regime of the lower reaches of Balason and Mahananda River of the sub-Himalayan region over the last 30 years by adopting a combined methodological framework of remote sensing and field survey. Results showed that initially the naturally vegetated areas had converted into crop land and grass land, tea plantation or bare land, and afterwards, the majority of it had been converted into built-ups. Besides, a noticeable amount of channel narrowing was directly proportionate to unrestricted sediment mining and embanking of the river channels, evidenced between 1987 and 2017. Comparison of measured multi-temporal channel width along with cross-profiles showed remarkable channel narrowing (18.8 m/year) as well as significant bed lowering (3.15 m). Studies reveal that the rivers have started showing signs of losing their existing equilibrium condition and if that happens then that will lead to the sinking of the ground water table, decreasing flood occurrence interval, destabilization of existing infrastructures associated with rivers, and destruction of river ecology. In order to restore the state of socio-hydrological as well as eco-hydrological amenities of these rivers, certain recommendations have also been made towards promoting the wise use of riverine resources by the local communities and policy makers.

Channel Confluence Dynamics in the Lower Chel River System, Eastern Sub-Himalayan West Bengal, India

In the present study channel confluence movements of two confluence points namely, Chel-Kumlai rivers’ confluence and Chel-Neora rivers’ confluence in the lower Chel-Neora river system has been analyzed using multi temporal Landsat images and topographical sheets. The study area is a part of region popularly known as ‘Dooars’ which falls in the zone of transition between the dissected outer Himalayan hill surface and the gently rolling Teesta-Brahmaputra plains, and is famous for notorious incidents of channel avulsion and river capture activities. This study tries to elucidate various fluvial processes responsible for confluence dynamics. The temporal scale of the study spans 62 years (1955-2017) and establishes the fact that the confluence points of the rivers have shifted both upstream and downstream in much variable rates during the assessment period. Avulsions, cut-offs, aggradations and river capture has been identified as controlling processes for such confluence dynamics.

Insecticide resistance to Temephos and synthetic Pyrethroids in Culex quinquefasciatus say from sub-Himalayan West Bengal, India

Culex quinquefasciatus Say is a vector for lymphatic filariasis in human populations throughout the world. Vector control, a major strategy for eradication of filariasis mainly involves the application of chemical insecticides giving rise to resistance against insecticides. In this context, a study was conducted to find out the resistance status of Cx. quinquefasciatus populations from seven densely populated sites in Siliguri sub division, West Bengal. Larval bioassay against temephos and adult bioassay against 5% malathion, 0.05% deltamethrin and 0.05% lambdacyhalothrin was performed following the standard WHO protocol. A total of 630 larvae and 360 adults were tested from one sampling site. The activity of major insecticide detoxifying enzymes i.e., carboxylesterases and monooxygenases was also assessed through biochemical assay. The seven tested populations were found to exhibit moderate to severe resistance (27.27% - 83.33% mortality) against deltamethrin, lambdacyhalothrin and temephos. However, all of the seven populations were found to be completely susceptible to malathion. This study provides new information on the current status of insecticide resistance in Cx. quinquefasciatus from this area, which may be helpful to the concerned authorities to design an effective mosquito control strategy for efficient management of vector-borne diseases.

<p class="Body"><strong>New eriophyoid mite (Acari: Eriophyoidea) from sub-Himalayan West Bengal, India</strong></p>

A new eriophyoid mite Unilox lataguriensis gen. nov. et sp. nov. on Ardisia solanacea (Poir.) Roxb. (Primulaceae) is described here from Jalpaiguri district of sub-Himalayan West Bengal, India. The new genus, belongs to the family Diptilomiopidae, subfamily Diptilomiopinae, and is very close to the genus Dialox.