Socioeconomic inequalities in psychosocial well-being among adolescents under the COVID-19 pandemic: a cross-regional comparative analysis in Hong Kong, mainland China, and the Netherlands.

BACKGROUND: Despite evidence on socioeconomic inequalities in psychosocial well-being of adolescents under the COVID-19 pandemic, the explanatory factors and their potential variations across contexts remained understudied. Hence, this cross-regional study compared the extent of inequalities and the mediating pathways across Hong Kong, Mainland China, and the Netherlands. METHODS: Between July 2021 and January 2022, 25 secondary schools from diverse socioeconomic background were purposively sampled from Hong Kong, Zhejiang (Mainland China), and Limburg (the Netherlands). 3595 junior students completed an online survey during class about their socioeconomic position, psychosocial factors, and well-being. Socioeconomic inequalities were assessed by multiple linear regressions using the Slope Index of Inequality (SII), whereas the mediating pathways through learning difficulty, overall worry about COVID-19, impact on family' financial status, resilience, trust in government regarding pandemic management, and adaptation to social distancing were examined by mediation analyses moderated by regions. RESULTS: The adverse psychosocial impact of COVID-19 was stronger in the Netherlands and Hong Kong compared with Mainland China. The greatest extent of socioeconomic inequalities in the change in psychosocial well-being was observed among students in the Netherlands (SII = 0.59 [95% CI = 0.38-0.80]), followed by Hong Kong (SII = 0.37 [0.21-0.52]) and Mainland China (SII = 0.12 [0.00-0.23]). Learning difficulty and resilience were the major mediators in Mainland China and Hong Kong, but to a lesser extent in the Netherlands. CONCLUSION: Socioeconomic inequalities in psychosocial well-being were evident among adolescents under the pandemic, with learning difficulty and resilience of students as the key mediators. Differences in the social contexts should be considered to better understand the variations in inequalities and mediating pathways across regions.

Secular trends of life expectancy and disability-free life expectancy at age 65 and associated gender and area-level socioeconomic inequalities in Hong Kong: a serial cross-sectional study between 2007 and 2020.

Background: Despite Hong Kong's world leading longevity, little is known about its associated disability burden and social patterning. Hence, this study assessed the gender-specific secular trends and area-level inequalities in life expectancy (LE) and disability-free life expectancy (DFLE) at age 65 in Hong Kong. Methods: Population structure, death records, and disability data in 2007, 2013, and 2020 were retrieved from the Census and Statistics Department to estimate LE and DFLE using the Sullivan Method. District-based sociodemographic indicators were used to compare LE and DFLE across 18 districts of Hong Kong in 2013. Findings: Between 2007 and 2020, LE at age 65 increased by 3.7 years (from 18.3 to 22.0) in men and by 2.1 years (from 22.7 to 24.8) in women. By contrast, DFLE increased more slowly, by 1.8 years (from 14.6 to 16.3) in men and by only 0.1 year (from 16.4 to 16.5) in women, leading to a substantial increase in proportion of life spent with disability. Results from multiple linear regression using district-based data in 2013 showed a similar extent of associations of education with LE and DFLE (mean year difference: 0.81 [95% CI: 0.14, 1.48] and 0.68 [0.10, 1.27], respectively, per 10% increase in average education level), while female gender was more strongly associated with LE (4.44 [3.56, 5.31]) than with DFLE (2.00 [1.18, 2.82]). Interpretation: Expansion of disability burden and male-female health-survival paradox hold true in Hong Kong. Unlike Western countries with a stronger socioeconomic patterning of DFLE, the extent of area-level socioeconomic inequalities in LE and DFLE appears to be more comparable in Hong Kong. Funding: Health and Medical Research Fund (Ref. no.: 19202031) by the Health Bureau of Hong Kong.

Experience of South and Southeast Asian minority women in Hong Kong during COVID-19 pandemic: a qualitative study.

BACKGROUND: Hong Kong has a relatively low incidence rate of COVID-19 across the globe. Nevertheless, ethnic minorities in Hong Kong, especially South Asians (SAs) and Southeast Asians (SEAs), face numerous physical, mental, social, economic, cultural and religious challenges during the pandemic. This study explores the experiences of SA and SEA women in a predominantly Chinese metropolitan city. METHODS: Ten SA and SEA women were recruited and face-to-face interviews were conducted. Questions about participants' daily life experience, physical and mental health conditions, economic situation and social interaction amid COVID-19 pandemic were asked to assess the impact of COVID-19. RESULTS: SAs and SEAs have a distinctive family culture, and women experienced significant physical and mental impact of COVID-19 due to their unique gender role in the family. In addition to taking care of their family in Hong Kong, SA and SEA women also had to mentally and financially support family members residing in their home countries. Access to COVID-related information was restricted due to language barrier. Public health measures including social distancing imposed extra burden on ethnic minorities with limited social and religious support. CONCLUSIONS: Even when COVID-19 incidence rate is relatively low in Hong Kong, the pandemic made life even more challenging for SAs and SEAs, which is a community already struggling with language barriers, financial woes, and discrimination. This in turn could have led to greater health inequalities. Government and civil organizations should take the social determinants of health inequalities into account when implementing COVID-19-related public health policies and strategies.

Socioeconomic inequality in the worsening of psychosocial wellbeing via disrupted social conditions during COVID-19 among adolescents in Hong Kong: self-resilience matters.

Background: Adolescents, especially the socioeconomically disadvantaged, are facing devastating psychosocial impact of the COVID-19 pandemic during their critical developmental period. This study aims to (i) examine the socioeconomic patterning of the worsening of psychosocial wellbeing, (ii) delineate the underlying mediating factors (i.e., overall worry about COVID-19, family's financial difficulty, learning problems, and loneliness), and (iii) explore the moderating effect of resilience in the inter-relationship among adolescents under COVID-19. Methods: Based on maximum variation sampling of 12 secondary schools of diverse socioeconomic background in Hong Kong, 1018 students aged 14-16 years were recruited and completed the online survey between September and October 2021. Multi-group structural equation modeling (SEM) by resilience levels was employed to delineate the pathways between socioeconomic position and the worsening of psychosocial wellbeing. Results: SEM analysis showed a significant total effect of socioeconomic ladder with the worsening of psychosocial wellbeing during the pandemic in the overall sample (ß = -0.149 [95% CI = -0.217 - -0.081], p < 0.001), which operated indirectly through learning problems and loneliness (both p < 0.001 for their indirect effects). Consistent pattern with stronger effect size was observed in the lower resilience group; nonetheless, the associations were substantially mitigated in the higher resilience group. Conclusion: In addition to facilitating self-directed learning and easing loneliness during the pandemic, evidence-based strategies to build up resilience among adolescents are critical to buffer against the adverse socioeconomic and psychosocial impacts of the pandemic or other potential catastrophic events in the future.

Determinants of depression and anxiety in homeless people: A population survey of homeless people in Hong Kong.

BACKGROUND: There are growing concerns about the homeless and mental health issues globally. This study aims to examine the mental health situation of homelessness and the determinants of anxiety and depression of them in Hong Kong. METHOD: The data from the largest territory-wide study of the homeless population in 2021 was analyzed. Descriptive statistics and logistic regressions were used to investigate the association between mental health and socioeconomic variables, including demographic background, economic indicators, COVID-19 worries, government measures, and respect by others. The symptoms of depression and anxiety were assessed using Patient Health Questionnaire (PHQ) and General Anxiety Disorder (GAD). RESULTS: The results showed that being female, food insecurity, and chronic diseases were the risk factors for anxiety and depression. A high level of respect by others was the protective factor for depression (adjusted OR 0.37, 95% CI [0.23, 0.61]) and anxiety (adjusted OR 0.40, 95% CI [0.24, 0.68]), compared to a low level of respect in the multivariate model. CONCLUSIONS: Providing medical outreach services, additional resources for social services, implementation of homeless-friendly policies, and a progressive supply of public and transitional housing would help enhance the well-being of the homeless population.

The mediating role of individual-level social capital among worries, mental health and subjective well-being among adults in Hong Kong during the COVID-19 pandemic.

The COVID-19 pandemic has substantially induced worries and affected individual mental health and subjective well-being. Nonetheless, a high level of social capital could potentially protect individuals who suffer from mental health problems and thus promote their subjective well-being, especially under the social distancing policies during the pandemic. To this end, based on a random sample of 1053 Hong Kong adults, structural equation modeling was applied to study the path relationships between the worries of COVID-19, social capital, mental health problems, and subjective well-being. The study found that worries during the pandemic were associated with mental health and subjective well-being, through social capital as a mediator. Moreover, social capital exhibited a stronger influence on mental health and subjective well-being in the economically inactive group than in the economically active group. This study highlights the important role of social capital during the COVID-19 pandemic. While Hong Kong's COVID-19 response has primarily focused on disease prevention, it must be noted that social services and mutual-help activities are also crucial for people to withstand the crisis.

Mitigating inequalities in community care needs of older adults with dementia: a qualitative case study of an integrated model of community care operated under the proportionate universalism principle.

BACKGROUND: Population ageing and community care on older adults, as well as the marked social inequalities in health, have received growing concern by the government and the community. This study evaluated the medico-social integrated day care model of the Cadenza Hub for older adults with dementia. We also examined whether services subsidized by the publicly funded graded financial support of the Community Care Service Voucher for the Elderly (CCSV) could mitigate social inequalities in community care needs, from the perspective of the caregivers. METHODS: In this qualitative case study, we adopted purposeful sampling strategy to recruit 14 caregivers of active day care service users with dementia, with different socioeconomic background and duration of service use, for face-to-face semi-structured in-depth interviews between June and August 2021. The transcribed data were closely read to capture key themes using thematic analyses. RESULTS: Caregivers faced tremendous caregiving burden in the absence of community care support and struggled in choosing care services. Most informants benefited from the day care service, whereas the financial support of CCSV was crucial to ensure equitable access to community care. Non-governmental organizations and social workers were the key to bridging the information gap. CONCLUSION: The integrated day care of the Cadenza Hub appeared to have addressed the unmet needs of older adults with dementia and their caregivers, including the socioeconomically disadvantaged with the CCSV support. The community care service delivery model might be applicable to address other health inequalities problems.

Transcriptome responses of RNAi-mediated ETH knockdown in Scylla paramamosain at different premolt substages.

Ecdysis triggering hormone (ETH) plays an important role in molting, reproduction, and courtship behavior in insects. To investigate the potential downstream pathways and genes of ETH in Scylla paramamosain, RNA interference (RNAi) was conducted on crabs at early (D0) and late (D2) premolt substages, and the transcriptome profiles of each group were compared by RNA sequencing. Real-time quantitative polymerase chain reaction (RT-qPCR) and semiquantitative polymerase chain reaction (RT-PCR) results showed a significant knockdown of ETH at D0 stage, whereas a significant increase was shown conversely in crabs at D2 substage after the injection of dsETH. A total of 242,979 transcripts were assembled, and 44,012 unigenes were identified. Transcriptomic comparison between crabs at D2 and D0 substages showed 2,683 differentially expressed genes (DEGs); these genes were enriched in ribosome and pathways related to transcription factor complex and cell part. Twenty DEGs were identified between dsETH-injected and dsGFP-injected crabs at D0 substage; these DEGs were involved in carbohydrate metabolism, one carbon pool by folate, and chitin binding. Twenty-six DEGs were identified between dsETH-injected and dsGFP-injected crabs at D2 substage; these DEGs were involved in calcium channel inhibitor activity, fat digestion and absorption, and cardiac muscle contraction. RT-qPCR verified the differential expression of the selected genes. In conclusion, crabs at D0 substage are more active in preparing the macromolecular complex that is needed for molting. Moreover, ETH has potential roles in carbohydrate metabolism, one carbon pool by folate, and chitin binding for crabs at D0 substage, while the role of ETH turns to be involved in calcium channel inhibitor activity, fat digestion and absorption, and cardiac muscle contraction at D2 substage to facilitate the occurrence of molting. The selected DEGs provide valuable insight into the role of ETH in the regulation of crustacean molting.

Inequalities in Psychiatric Morbidity in Hong Kong and Strategies for Mitigation.

This study explores the social gradient of psychiatric morbidity. The Hong Kong Mental Morbidity Survey (HKMMS), consisting of 5719 Chinese adults aged 16 to 75 years, was used. The Chinese version of the Revised Clinical Interview Schedule (CIS-R) was employed for psychiatric assessment of common mental disorders (CMD). People with a less advantaged socioeconomic position (lower education, lower household income, unemployment, small living area and public rental housing) had a higher prevalence of depression and anxiety disorder. People with lower incomes had worse physical health (OR 2.01, 95% CI 1.05-3.82) and greater odds of having CMD in the presence of a family history of psychiatric illnesses (OR 1.67, 95% CI 1.18-2.36). Unemployment also had a greater impact for those in lower-income groups (OR 2.67; 95% CI 1.85-3.85), whereas no significant association was observed in high-income groups (OR 0.56; 95% CI 0.14-2.17). Mitigating strategies in terms of services and social support should target socially disadvantaged groups with a high risk of psychiatric morbidity. Such strategies include collaboration among government, civil society and business sectors in harnessing community resources.

Resilience and coping strategies of older adults in Hong Kong during COVID-19 pandemic: a mixed methods study.

BACKGROUND: Despite the adverse physical health impact of COVID-19 on older adults, whether they are psychosocially vulnerable under the pandemic remains debatable. In this mixed methods study, we examined the psychosocial vulnerability of older adults relative to their younger counterparts and explored how they coped with the pandemic. METHODS: From September to October 2020, 1067 adults in Hong Kong were randomly sampled and completed a telephone survey, whereas 10 older adults were recruited for individual interviews between September 2020 and April 2021. Quantitative measurements included subjective well-being, worries about COVID-19, and changes in social capital and social interaction since the pandemic. The transcribed qualitative data were closely read and summarized using thematic analyses. RESULTS: Compared with younger adults, older adults tended to be less worried about COVID-19 infection and economic activity/livelihood, despite being slightly more worried about supplies of personal protective equipment. They also had better subjective well-being in terms of happiness and life satisfaction, with their social capital and social interaction less affected. In addition, five themes emerged from the qualitative interviews: (1) life philosophy; (2) economic security; (3) telecommunication; (4) role of community organizations and social workers; and (5) positive coping strategies. CONCLUSIONS: Older adults in this study showed better psychosocial well-being than their younger counterparts under the COVID-19 pandemic, which challenged the deeply rooted societal stereotype about the vulnerability of older adults. The stronger resilience for positive coping, technological assistance, and targeted government and community support may have protected older adults from distress during the pandemic.

The impact of trust in government on pandemic management on the compliance with voluntary COVID-19 vaccination policy among adolescents after social unrest in Hong Kong.

Background: The launch of COVID-19 vaccines among students provides an opportunity to re-open schools safely. Nonetheless, under the voluntary vaccination policy, the lack of trust in government since the unprecedented massive social unrest in Hong Kong may hinder the vaccination progress. This study aims to assess the impact of trust in government regarding pandemic management on the willingness, uptake, and intention of COVID-19 vaccination among students in Hong Kong. Methods: Based on maximum variation sampling of 12 secondary schools of diverse socioeconomic background, 1,020 students aged 14-16 years completed an online survey between September and October 2021. Results: 59.2% of the sample received at least one dose of the COVID-19 vaccine, 25.2% showed willingness of vaccination, 44.7% of the unvaccinated intended to receive the vaccine, whereas 13.4% were trustful to the government regarding pandemic management. Results from multivariable logistic regressions showed independent associations of trust with greater vaccination uptake [aOR = 1.63 (95% CI = 1.06-2.52), compared to distrust], willingness [aOR = 12.40 (7.72-19.93)], and intention [aOR = 4.49 (2.06-9.75)]. However, the impact of trust on vaccine uptake reversed [aOR = 0.53 (0.32-0.87)] after additional adjustment for the willingness of vaccination. Conclusion: Students with higher trust in government regarding pandemic management tended to have greater vaccination willingness and hence uptake; nonetheless, given the same level of willingness, distrust might have facilitated a faster adoption of vaccination as a self-initiated protective behavior. As the level of trust is generally low among secondary school students in Hong Kong, rebuilding trust during adolescence is of importance for better preparedness of the next pandemic.

Socioeconomic inequality in mental well-being associated with COVID-19 containment measures in a low-incidence Asian globalized city.

The COVID-19 pandemic exposes and amplifies pre-existing inequalities even in places with relatively well-controlled outbreaks such as Hong Kong. This study aimed to explore whether the socioeconomically disadvantaged fare worse via various types of worry in terms of their mental health and well-being. Between September and October 2020, 1067 adults in Hong Kong were recruited via a cross-sectional population-wide telephone survey. The inter-relationship between deprivation, types of worry, mental health disorders, and subjective well-being was assessed using structural equation modelling. Results showed significant total effects of deprivation on worries about being infected (p = 0.002), economic activities and livelihood (p < 0.001), and personal savings (p < 0.001), as well as mental health disorders (p < 0.001) and subjective well-being (p < 0.001). Specifically, worry about economic activities and livelihood partly mediated the total effect of deprivation on mental health disorders (p = 0.004), whereas worry about personal savings and worry about economic activities and livelihood partially mediated the total effect of deprivation on subjective well-being (p = 0.007 and 0.002, respectively). Socioeconomic inequality, particularly in mental health and well-being, could be exacerbated via people's economic concerns during the pandemic, which was largely induced by the COVID-19 containment measures rather than the pandemic per se given the relatively low COVID-19 incidence in Hong Kong.

Socioeconomic Patterns of COVID-19 Clusters in Low-Incidence City, Hong Kong.

Although coronavirus disease (COVID-19) outbreaks have been relatively well controlled in Hong Kong, containment remains challenging among socioeconomically disadvantaged persons. They are at higher risk for widespread COVID-19 transmission through sizable clustering, probably because of exposure to social settings in which existing mitigation policies had differential socioeconomic effects.

Differential Impacts of Multimorbidity on COVID-19 Severity across the Socioeconomic Ladder in Hong Kong: A Syndemic Perspective.

The severity of COVID-19 infections could be exacerbated by the epidemic of chronic diseases and underlying inequalities in social determinants of health. Nonetheless, there is scanty evidence in regions with a relatively well-controlled outbreak. This study examined the socioeconomic patterning of COVID-19 severity and its effect modification with multimorbidity in Hong Kong. 3074 local COVID-19 cases diagnosed from 5 July to 31 October 2020 were analyzed and followed up until 30 November 2020. Data on residential addresses, socio-demographic background, COVID-19 clinical conditions, and pre-existing chronic diseases of confirmed cases were retrieved from the Centre for Health Protection and the Hospital Authority. Results showed that, despite an independent adverse impact of multimorbidity on COVID-19 severity (aOR = 2.35 [95% CI = 1.72-3.19]), it varied across the socioeconomic ladder, with no significant risk among those living in the wealthiest areas (aOR = 0.80 [0.32-2.02]). Also, no significant association of the area-level income-poverty rate with severe COVID-19 was observed. In conclusion, the socioeconomic patterning of severe COVID-19 was mild in Hong Kong. Nonetheless, socioeconomic position interacted with multimorbidity to determine COVID-19 severity with a mitigated risk among the socioeconomically advantaged. Plausible explanations include the underlying socioeconomic inequalities in chronic disease management and the equity impact of the public-private dual-track healthcare system.

Insulin-like androgenic gland hormone from the shrimp Fenneropenaeus merguiensis: Expression, gene organization and transcript variants.

Male sex differentiation in the crustacean is best known to be controlled by the insulin-like androgenic gland hormone (IAG). In this report, the cDNA and gene of the shrimp Fenneropenaeus merguiensis FmIAG were studied and characterized. FmIAG gene shares a high sequence identity in the coding region as well as the promoter region with that of F. chinensis. FmIAG gene is most likely consists of 5 exons and 4 introns. The cDNA reported here is the most abundant transcript that retained cryptic intron 4. The use of different splicing acceptor sites in exon 2 can produce a long-form FmIAG transcript variant with 6 additional amino acids inserted. Splicing of cryptic intron 4 would produce a transcript variant with a different C-terminal end. Therefore 4 different FmIAG transcripts can be produced from the FmIAG gene. During the molt cycle, the expression level of FmIAG was low in the early intermolt, increase steadily towards the late premolt and decreased rapidly in the early postmolt. In addition to the androgenic gland, FmIAG is also expressed in the hepatopancreas and ovary of adult females. Unilateral eyestalk ablation caused a significant increase in FmIAG transcript suggesting that the eyestalk consists of inhibiting factor(s) that suppressesFmIAGexpression. To explore the function of FmIAG in males, injection of FmIAG dsRNA knock-down the expression of FmIAG and up-regulated the expression of the vitellogenin gene in the testis and hepatopancreas. Interestingly a CHH-like gene identified in the androgenic gland was down-regulated. CHH-like gene knock-down resulted in altered expression of FmIAG in males suggesting that the CHH-like may be involved in FmIAG's regulation. RT-PCR with specific primers to the different transcript variant were used to determine if there is an association of different sizes of male and the type of IAG transcript. Results indicated that a high percentage of the large male shrimp expressed the long-form of FmIAG. The results suggested that FmIAG may be useful as a size marker for male shrimp aquaculture. In summary, the results of this study have expanded our knowledge of shrimp insulin-like androgenic gland hormone in male sex development and its potential role as a marker gene for growth regulation in shrimp.

Molecular characterization and expression dynamics of three key genes in the PI3K-AKT pathway reveal its involvement in the immunotoxicological responses of the giant river prawn Macrobrachium rosenbergii to acute ammonia and nitrite stress.

Ammonia nitrogen and nitrite are two common forms of environmental toxicants for aquatic organisms including crustaceans. The PI3K-AKT pathway is an important intracellular signaling pathway related to cellular stress response, but involvement of this pathway in the immunotoxicological response of decapod crustaceans to aquatic toxicants such as ammonia nitrogen and nitrite still remains enigmatic. In this study, based on transcriptome mining and molecular cloning techniques, three key genes (named as MrPI3K, MrAKT and MrFoxO) in the PI3K-AKT signaling pathway were identified from the giant river prawn Macrobrachium rosenbergii. Sequence homology and phylogenetic analysis revealed that all the three genes harbored signature sequences of corresponding protein families, and shared high levels of similarities with their respective homologs from other species. MrPI3K, MrAKT and MrFoxO all displayed ubiquitous tissue distribution profiles, but their expression levels varied to a great extend among different tissues and between sexes. Following exposure to nitrite (20 mg/L nitrite-N) or ammonia (25 mg/L total ammonia-N) stresses for 24 h and 48 h, the three genes all responded by altering their expression levels at different time points, but they didn't show uniform expression patterns following these stresses, indicating the diversified roles of these genes in different tissues and the complexity of this signaling pathway. Remarkably, MrPI3K and MrAKT were induced only in the hemocytes and intestine, respectively, indicating their specific roles in these organs. Our study demonstrated the potential utility of these genes as biomarkers of acute ammonia or nitrite toxicity in prawns, and also provided evidence that the PI3K-AKT pathway is involved in the immunotoxicological responses to nitrite and ammonia stress in M. rosenbergii.

Investigation of Gene Sequence Divergence, Expression Dynamics, and Endocrine Regulation of the Vitellogenin Gene Family in the Whiteleg Shrimp Litopenaeus vannamei.

In this report, we studied the vitellogenin gene family in the whiteleg shrimp Litopenaeus vannamei by transcriptomics, bioinformatics, and molecular biology methods. At least three moderately homologous vitellogenin (Vg) genes (i.e. LvVg1, LvVg2, and LvVg3) were identified in the genome. The deduced LvVg proteins consisted of a vitellogenin_N domain, a DUF1943 domain, and a VWD domain typical of most vitellogenins from oviparous animals. LvVg1 was the most abundant Vg expressed in the hepatopancreas and ovary of maturing females. Furthermore, multiple isoforms of LvVg1 were evolved presumably due to the need for rapid Vg production during the rapid phase of vitellogenesis. LvVg transcripts were detected in different larval stages, juveniles, and subadults. During the non-reproductive cycle, LvVg expression in the hepatopancreas peaked at the intermolt stages. During the female vitellogenesis cycle, a two-phase expression pattern of LvVg1 gene was observed in the hepatopancreas and ovary. Moreover, the eyestalk optic nerve, brain, and thoracic ganglion consisted of factors that differentially regulated the expression of the three Vg genes. In addition to their reproduction-related roles, Vg may also be involved in growth and molt-related processes. Phylogenetic analysis revealed the early expansion and separation of these Vg genes, and it is most likely correlated with the expansion of Vg's function. In conclusion, the evolution of multiple LvVg1 isoforms and the acquisition of different Vg genes (i.e. LvVg2 and LvVg3) may occur universally in most decapods. Full information on the total number of Vg genes and precise knowledge on the expression pattern and endocrine regulation of each Vg during all life cycle stages are crucial for us to understand the roles of this emerging gene family in the control of shrimp reproduction and other non-reproductive processes.

Comparative transcriptomics reveals eyestalk ablation induced responses of the neuroendocrine-immune system in the Pacific white shrimp Litopenaeus vannamei.

In decapod crustaceans, eyestalk ablation is widely used to expedite ovarian maturation and spawning because of the removal of a gonad inhibiting hormone produced by the X-organ sinus gland. However, eyestalk ablation also results in negative impacts on the immunocompetence of the eyestalk-ablated females. In the current study, we investigated the impact of eyestalk ablation on the transcriptomic responses of three major nervous organs of shrimp, including the eyestalk ganglion, brain and thoracic ganglion, using the Illumina Hiseq™ 4000 platform. A total of 48,249 unigenes with an average length of 1253 bp and a N50 value of 2482 bp were obtained. Following eyestalk ablation treatment, a total of 2,983, 6325 and 6575 unigenes were detected as differentially expressed (log2Ratio >1 and FDR <0.05) from the eyestalk, brain and thoracic ganglia, respectively. Functional GO and KEGG analysis of these differential expression genes (DEGs) showed that these DEGs were associated with a wide variety of biological processes and pathways. The distribution of DEGs among three comparison groups was similar, and many DEGs were mapped to the phagosome pathway, indicating that eyestalk ablation triggers activation of the neuroendocrine-immune (NEI) system. Interestingly, several important pathways were uniquely enriched in the brain tissue, suggesting that the brain may play a crucial role in the NEI system in response to eyestalk ablation. This is the first report on the transcriptomic regulation of the nervous system in response to eyestalk ablation in L. vannamei. The genes and pathways identified in this study will help to elucidate the molecular mechanisms of neuroendocrine-immune responses to eyestalk ablation in penaeid shrimp.

Crustacean neuroparsins-a mini-review.

Crustacean neuroparsins are poly-cysteine rich neuropeptides that share some similarities with the ovary ecdysteroidogenesis hormone (OEH) of mosquitoes, the N-terminal end of the growth factor binding protein region of the vertebrate and mollusk insulin-like growth factor binding protein and single insulin binding domain protein. Neuroparsins can promote reproduction and neurite outgrowth in various insects. Though many studies have been made in insects, the amount of work reported in crustaceans is still limited. This review emphasizes the neuroparsins found in decapod crustaceans with references to the neuroparsin first discovered in insects. To be more complete in identifying all the neuroparsin members and to understand the structure/function relationship within a single species, we have collected all neuroparsins from the GenBank and our transcriptome datasets. Then, we employed a comparative approach to study the sequence homology, tissue expression patterns, making predictions of their function and the evolutionary relationship particularly in decapod crustaceans. Results from alignment and phylogenetic studies indicated that crustacean neuroparsins consist of unique feature that can be used as criteria for their classification. These features include the presence of 12 cysteine residues in the mature peptide, the strict spacing between these cysteine residues and the size of the mature peptide. Because of the limited data on the expression information, the functions of most neuroparsin are unknown. The review will focus on the site of synthesis, expression, functions, the sequence homology and the evolutionary relationship of this group of neurohormones.

Functional characterization of a protein inhibitor of activated STAT (PIAS) gene in Litopenaeus vannamei.

Protein inhibitor of activated STAT (PIAS) plays a critical role in the feedback modulation of the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway as a negative regulator in mammals and Drosophila, but the function of PIAS in crustaceans is still unclear. In this study, a PIAS termed LvPIAS was cloned and characterized from Litopenaeus vannamei. The full length of LvPIAS was 3065 bp, including a 2361 bp open reading frame (ORF) coding for a protein of 786 aa. LvPIAS expression was most abundant in muscle and could respond to the challenge of LPS, Vibrio parahaemolyticus, Staphhylococcus aureus, Poly I: C and white spot syndrome virus (WSSV). LvPIAS could be induced by the transcription factor LvSTAT, but LvPIAS could inhibit the transcriptional activity of LvSTAT to the LvPIAS promoter conversely, which indicated that there was a negative feedback loop between LvSTAT and LvPIAS. Furthermore, RNAi-mediated knockdown of LvPIAS shrimps showed higher survival rate to WSSV infection than those in the control group (dsGFP injection), suggesting that LvPIAS may play a negatively role against WSSV infection.