Population Genomics of an Anadromous Hilsa Shad Tenualosa ilisha Species across Its Diverse Migratory Habitats: Discrimination by Fine-Scale Local Adaptation

The migration of anadromous fish in heterogenic environments unceasingly imposes a selective pressure that results in genetic variation for local adaptation. However, discrimination of anadromous fish populations by fine-scale local adaptation is challenging because of their high rate of gene flow, highly connected divergent population, and large population size. Recent advances in next-generation sequencing (NGS) have expanded the prospects of defining the weakly structured population of anadromous fish. Therefore, we used NGS-based restriction site-associated DNA (NextRAD) techniques on 300 individuals of an anadromous Hilsa shad (Tenualosa ilisha) species, collected from nine strategic habitats, across their diverse migratory habitats, which include sea, estuary, and different freshwater rivers. The NextRAD technique successfully identified 15,453 single nucleotide polymorphism (SNP) loci. Outlier tests using the F_ST OutFLANK and pcadapt approaches identified 74 and 449 SNPs (49 SNPs being common), respectively, as putative adaptive loci under a divergent selection process. Our results, based on the different cluster analyses of these putatively adaptive loci, suggested that local adaptation has divided the Hilsa shad population into two genetically structured clusters, in which marine and estuarine collection sites were dominated by individuals of one genetic cluster and different riverine collection sites were dominated by individuals of another genetic cluster. The phylogenetic analysis revealed that all the riverine populations of Hilsa shad were further subdivided into the north-western riverine (turbid freshwater) and the north-eastern riverine (clear freshwater) ecotypes. Among all of the putatively adaptive loci, only 36 loci were observed to be in the coding region, and the encoded genes might be associated with important biological functions related to the local adaptation of Hilsa shad. In summary, our study provides both neutral and adaptive contexts for the observed genetic divergence of Hilsa shad and, consequently, resolves the previous inconclusive findings on their population genetic structure across their diverse migratory habitats. Moreover, the study has clearly demonstrated that NextRAD sequencing is an innovative approach to explore how dispersal and local adaptation can shape genetic divergence of non-model anadromous fish that intersect diverse migratory habitats during their life-history stages.

Depression, anxiety, and stress among public university students in Bangladesh during the COVID-19 pandemic

“Coronaphobia” has spread across the world due to the overwhelming impact of coronavirus-2019 (COVID-19). The education sector has suffered from the pandemic, and university students find themselves in an unprecedented situation. Many university students in Bangladesh require psychological intervention due to adverse mental health conditions created by the COVID-19 pandemic. This cross-sectional study was conducted to evaluate the psycho­logical conditions among public university students in Bangladesh during university campus closures necessitated by the pandemic. It also sought to ascertain factors associated with adverse psychological conditions during this period. Convenience and snowball sampling techniques were employed. In all, 1,382 university students participated in an online survey during the COVID-19 pandemic. Relationships between student demographic factors and DASS 21 subscales were determined using linear regression models. Students were classified as suffering from anxiety (26.85 percent), normal depression (25.47 percent), moderate depression (29.52 percent), or extremely severe depression (17.73 percent). Students who lived with their families reported less adverse mental health. Factors strongly associated with students’ psychological conditions include age, academic field, university year, perception of their own mental health condition during the COVID-19 pandemic, safety concerns about their living place relative to COVID-19, perceptions about social life, academic profile, academic performance, concerns about pandemic impact on their studies, and part-time jobs during the pandemic. Outcomes of this research may assist social organizations and health workers to identify psychologically vulnerable university students in order to support them more effectively. Our findings could also be integrated into comprehensive pandemic control efforts.

Reproductive Biology and Ecology of the Green Mussel Perna viridis: A Multidisciplinary Approach

A multidisciplinary approach was applied to explore deeper knowledge about the reproductive biology and ecology of the green mussel (Perna viridis) by interlinking among ecological factors, ingested gut plankton, gonad fatty acid profile, and reproductive traits. Mussels were collected throughout the year from the coastal region of the Bay of Bengal of Bangladesh, and the histological analysis of 242 mussels revealed five stages of gametogenesis with an annual spawning season from January to April. The gonadosomatic index showed a strong correlation with the water quality parameters, ingested gut plankton groups, and gonadal fatty acids, and also displayed prominent effects of seasonality. In all datasets, we performed principal component analysis in which the first two principal components showed that seasonality explained >65% of the variability, and the multivariate spaces of seasonality corresponded to the gonad development. High salinity, nutrients, chlorophyll a, and plankton abundance in the water column were positively correlated with gonad development and the spawning of mussels. During the development stage, mussel ingested more plankton, particularly Bacillariophyceae and Pyrrophyceae, which were an important source of increased n-3 polyunsaturated fatty acids content in gonads. Furthermore, gonads accumulated more lipids and saturated fatty acids during the mature and spawning stages, which were probably utilized during embryogenesis and early larval development as energy sources and constituents of the cell membrane. This research provides a model toward a better understanding of reproductive biological traits and how these traits are interrelated with the surrounding environmental variables of the green mussel, which would be helpful in marine aquaculture and the sustainable exploitation of the fishery resources.

Endoscopic third ventriculostomy in children: problems and surgical outcome: analysis of 34 cases

Background

Endoscopic third ventriculostomy (ETV) has been established as a viable treatment option for obstructive hydrocephalus of children over 6 weeks of age. ETV in pediatric groups may be unsuccessful due to the failure of absorption of cerebrospinal fluid (CSF) or reclosure of ventriculostomy stoma or due to infection. The exact cause is still debatable. Some issues like failure to eliminate the second membrane during the procedure or formation of the new arachnoid membrane at the stoma are still not clear. This study aims to assess the surgical failure of ETV and its predisposing factors.

Methods

Thirty-four pediatric patients with hydrocephalus were analyzed retrospectively. The patients’ age limit was between 2.5 months and 14 years. This is a retrospective study of 34 patients in a single private hospital between June 2012 and January 2018. Patients having hydrocephalus in pediatric groups more than 6 weeks of age were included in the study.

Results

The mean age of all patients was 51.25 ± 53.90 months and the mean follow-up period was 50.47 ± 20.84 months. Of 34 surgeries, the success rate was 79% and the failure rate was 21%. Within 2 years, the success rate was 68.42% and above 2 years’ success rate was 93.33%. In this series, 7 cases of ETV were re-explored and found ventriculostomy stoma closure in 3 cases, the presence of the second membrane in re-exploration 2 cases, and presence of inflammatory arachnoid membrane in re-exploration 2 cases. The use of dexamethasone around the stoma in inflammatory stoma was useful, having no recurrence. In one patient of the second membrane probably due to absorption failure in communicating hydrocephalus re-exploration was failed and was managed successfully with VP shunt.

Conclusions

Predisposing factors causing ETV failure are ventriculostomy stoma closure by new arachnoid granulation tissues, remnants of the second membrane inside the stoma, CSF absorption failure, infection/high protein in CSF and inappropriate patient selection.

Growth and Survival of Goldfish (Carassius auratus) Juveniles Fed Tubifex, Custard Meal and Commercial Feeds

An experiment was conducted to investigate suitable feed for Carassius auratus juveniles. 30-day-old juveniles (3.31±0.14 cm and 0.84±0.3 g) were reared in glass aquaria (50×30×30 cm3) at stocking density of 10 juveniles/aquaria in triplicates. The juveniles were fed four different feeds, Tubifex, egg custard, commercial feed, and aquarium feed, twice daily until satiation. After 28 days of trial, fish fed custard and Tubifex had significantly higher survival rates (91% and 88%) than those fed aquarium feed (81%, P < 0.05) and commercial fish feed (75%, P < 0.05). The final length, weight, absolute growth rate and metabolic growth rate were significantly varied among the treatments (P < 0.05). However, no significant differences were evident in weight gain and SGR (P > 0.05). The fish fed custard and Tubifex were comparable in terms of growth performance (P > 0.05) while a significantly lower growth rate was found in fish fed commercial feed (P < 0.05). Fish fed Tubifex and custard had significantly higher protein content (15.28% and 14.86%, respectively) than those fed commercial fish feed (13.41%) and aquarium feed (12.21%). The overall findings suggest that the formulated egg custard can promote growth and survival in goldfish.

Dietary supplementation of host‐associated lactic acid bacteria modulates growth, metabolic activities, and immune‐related gene expression in giant freshwater prawn, Macrobrachium rosenbergii

The present study was carried out to evaluate the dietary effects of host‐associated lactic acid bacteria on growth performance, metabolic enzyme activities, and immune response of Macrobrachium rosenbergii juveniles. To formulate the test diets, a control (Con) diet was supplemented with a commercial probiotic and three host‐derived bacteria Enterococcus faecalis (EC), Lactococcus lactis I (LC‐I), and L. lactis II (LC‐II), which were previously isolated from the gastrointestinal tract of adult individuals of M. rosenbergii. Juvenile M. rosenbergii (0.65 ± 0.008 g) were randomly stocked at 20 individuals/100 L of fiberglass tanks with three replications for each test diet. After 50 days, juveniles fed the diets LC‐I and LC‐II showed significantly higher (p < .05) weight gain, specific growth rate, and the lowest feed conversion ratio. The analyses of glutamic oxaloacetate transaminase and glutamic pyruvate transaminase in muscle and hepatopancreas revealed significantly (p < .05) reduced values in LC‐I fed juveniles. The total hemocyte count and phenoloxidase activity were significantly increased (p < .05) in LC‐I and LC‐II fed juveniles. The relative mRNA expression patterns of immune‐related α2‐M, LGBP, ProPO, Cu, Zn‐SOD, TG, PE, AKP, and ACP genes were significantly (p < .05) upregulated in juveniles fed with LC‐I followed by the diet LC‐II. Finally, the study suggests that the growth performance and immune response of M. rosenbergii can be improved through supplementation of host‐associated L. lactis bacteria for its higher production.

Status and view toward COVID-19 and mental health among vulnerable group: A cross-sectional rapid survey among rickshaw pullers of Bangladesh

Bangladesh has experienced the hardest coronavirus disease 2019 (COVID-19) impact on the socioeconomic sector. The underprivileged group, rickshaw pullers, faced extreme situations due to the pandemic. This rapid cross-sectional study was conducted among 190 rickshaw pullers of Dhaka city. Knowledge, attitude, and practice (KAP) survey was carried out to evaluate their view and COVID-19 response level. Descriptive statistics were calculated. Statistical analyses such as Kruskal–Wallis or Mann–Whitney U tests, Spearman’s rank correlation, the linear regression model, Chi-square test, and Fisher’s exact test were performed where appropriate. The majority of them rated the high impact of COVID-19 on their income and mental health. Age, living with family, accommodation type, income, and COVID-19 infection history were found as associating factors with these impacts. A large number of the study population demonstrated low knowledge level (42.63 percent), moderate attitude level (57.37 percent), and moderate practice level (58.95 percent) toward COVID-19 and the vaccination. Positive attitude could reduce their mental health concern due to the pandemic. The study population mostly used their surrounding people as the main source of COVID-19 information. However, digital media have played a crucial role to disseminate authentic information. Ensuring better socioeconomic conditions can help these highly vulnerable people to be effectively prepared and respond against the pandemic.

pH induced stress enhances lipid accumulation in microalgae grown under mixotrophic and autotrophic condition

Production of biodiesel together with wastewater treatment and CO2 sequestration is a promising technology. The growing levels of carbon dioxide in the atmosphere increase the amount of dissolved CO2 in natural watercourses, triggering the increase in concentrations of bicarbonate and hydrogen ions while dropping those of carbonate and hydroxyl ions. The active carbon cycling in coastal areas, which can result in periodic and daily fluctuations in pH and CO2 concentrations that may surpass those anticipated for the extensive marine ecosystems, is regarded as one of the consequences of climate change. Studies were conducted to examine the effects of various pH levels on algal growth and lipid production in order to better understand how the growth of algae may be influenced in such conditions. In the present study, the influence of three different pH levels (6, 8, and 10) was studied to evaluate microalgae’s carbohydrate utilisation and lipid accumulation during the operation’s starvation phase (SP). Microalgae, in the study, were cultivated in two modes, namely mixotrophic [growth phase (GP)] and autotrophic [pH-induced (SP)] conditions. Enhancement in biomass formation, and intracellular carbohydrate accumulation were recorded during the GP operation, while noticeable lipid productivities (Total/neutral, 26.93/10.3%) were observed during SP operation at pH 8. Pigment analysis showed variations in both the procedures where higher Chl a concentration was noticed in GP, and higher Chl b was detected during SP. Nile red fluorescent staining strongly supports the existence of intracellular lipid bodies (LB). GC analysis of fatty acid methyl esters (FAME) showed the existence of a substantial amount of saturated fatty acids (SFA) compared with unsaturated fatty acids (USFA). Efficient wastewater treatment with nutrient assimilation was reported during the GP operation, demonstrating the phyco-remediation.