Search

The control of CD4 gene expression is essential for proper T lymphocyte development. Signals transmitted from the T-cell antigen receptor (TCR) during the thymic selection processes are believed to be linked to the regulation of CD4 gene expression during specific stages of T cell development. Thus, a study of the factors that control CD4 gene expression may lead to further insight into the molecular mechanisms that drive thymic selection. In this review, we discuss the work conducted to date to identify and characterize the cis-acting transcriptional control elements in the CD4 locus and the DNA-binding factors that mediate their function. From these studies, it is becoming clear that the molecular mechanisms controlling CD4 gene expression are very complex and differ at each stage of development. Thus, the control of CD4 expression is subject to many different influences as the thymocyte develops.

Background: Innovative HIV and pregnancy prevention products that are easy to use and acceptable are needed to expand prevention options, especially for adolescent girls and young women (AGYW). A microarray patch (MAP)--a novel drug delivery system--is being developed to administer HIV PrEP and as a multipurpose prevention technology (MPT) to protect from HIV and unintended pregnancy. Feedback from user/stakeholder assessments early in product development can help refine product features to meet the needs of intended users. Methods: Employing focus group discussions (FGD), key informant interviews, and mock-use exercises with prototypes, we explored user/stakeholder perceptions of the MAP technology and needs/preferences regarding product features that could influence usability, acceptability, and programmatic integration. This study was conducted among 6 target audiences in 8 rural and urban sites in South Africa and Uganda. Overall, we conducted 14 FGDs with AGYW (18-24 years), 2 with female sex workers (FSW), 8 with heterosexual men, and 2 with men who have sex with men. We also interviewed 20 HIV and family planning health care providers, 4 FSWs, and 6 policymaker/program managers. Seventy additional participants representing all user groups evaluated the usability of MAP prototypes. Findings were coded/analyzed using Atlas.Ti software. Results: All groups expressed interest in the MAP technology, reporting potential advantages over methods such as pills and injectables. Most participants preferred a smaller MAP and long-term protection (1-3 + months) with some differences noted across groups. Self-administration and discreet use were valued by all. Preferred application site and duration of application varied by MAP size. An MPT MAP was preferred over an HIV prevention-only MAP by most AGYWs and FSWs. Participants wanted more confidence from the feedback indicator regarding correct MAP application and drug delivery. Participants wanted more information about how the MAP works and voiced concerns about potential drug-related side effects and effectiveness. Conclusions: This early-stage user assessment of MAPs for HIV PrEP and MPT found high potential acceptability among users/stakeholders. MAP size and duration of protection are key attributes that will influence acceptability and uptake. Ongoing user assessments are essential to refine MAP prototypes to better meet users' needs., OA04.01 M. Kilbourne-Brook (1); A. Ismail (2); S. Magni (2); T. Fellows (2); A. Ruhweza Katahoire (3); F. Ayebare (3); G. Siu (3); F. Semitala (4); P. Kyambadde (5); D. [...]

Wenyan Nong, Zhe Qu, Yiqian Li, Tom Barton-Owen, Annette Wong and colleagues provide genomes and small RNA transcriptomes for the mangrove horseshoe crab and the tri-spine horseshoe crab. They show that horseshoe crabs have undergone three rounds of whole genome duplication and shed light on how gene families and microRNAS evolved following this genome duplication event.

Stable isotope tracer addition can enhance the isotopic differences of primary producers for a wider food-web resolution than the use of natural abundance stable isotopes (NASIs) alone, particularly in ecosystems where primary producers have similar NASI values. To investigate the food sources and the trophic status of benthic infauna in an intertidal area near a Halophila minor seagrass bed within inner Tai Tam Bay, Hong Kong, China, a 15N addition experiment was conducted, and the results were compared with those from NASI data. Only benthic microalgae (BMA) were labeled by applying 15N-enriched NH4Cl to the sediment daily for the first 7 days during a 21-day study. In contrast to the NASI results, Bayesian mixing models based on the isotope tracer experiment suggested a larger dietary contribution of BMA for nematode Daptonema sp. and copepods, whereas a higher reliance on phytoplankton and seagrass detritus was noted for polychaete Neanthes sp. However, both NASI and isotope tracer addition demonstrated that seagrass detritus was a major food source for nematode Spilophorella sp. The present isotope tracer experiment also revealed a contrasting result of the relatively lower contribution of meiofauna in the diets of carnivores/omnivores as compared to the results of NASIs. This finding suggested that the isotope values in these consumers may have not reached an equilibrium with the added isotope in the study period. Thus, there is a need for applying NASI coupled with isotope tracer addition in the investigation of ecosystems in which primary producers have similar isotope values, especially in ecosystems with lower tissue turnover rates, in order for a more accurate determination of dietary contribution and trophic status of consumers in the food-web study.

As a well-known example of “living fossil,” horseshoe crabs are ecologically significant macroinvertebrates in coastal and estuarine ecosystems. The tri-spine horseshoe crab, Tachypleus tridentatus, has been widely utilized for Tachypleus amebocyte lysate production and food consumption since the 1980s, which led to considerable population declines along the west coast of the Pacific Ocean. The declining horseshoe crab population is expected to have ecological and social impacts. Stock enhancement through captive rearing of juveniles is cited as an important alternative to repopulate the native T. tridentatus, which in turn supports sustainable resource utilization and research activities. The hatchery production techniques for this species have gradually developed following the mass culture efforts in Japan since the late 1980s. However, the previous studies have primarily concerned the feed types and husbandry conditions to maximize the growth and survival of the juveniles. Little is known about the practicability and effectiveness of releasing large numbers of hatchery-bred individuals through releasing programs. In this review, we (1) summarize the available captive breeding and rearing techniques, (2) discuss the release strategies that could potentially improve the survival of released juveniles, and (3) identify the future opportunities and challenges in establishing technical frameworks to support responsible stock enhancement programs for T. tridentatus. The information should benefit future horseshoe crab fisheries management efforts in the attempt to restore the severely depleted populations.

Horseshoe crabs are currently threatened by escalating human stresses along the Indo-Pacific coastline. Conservation of their remaining populations, however, is hindered by limited baselines throughout their ranges. We performed a questionnaire survey of conservation experts from diverse geographic regions to identify baselines, prominent threats, impediments and alternative strategies that prioritize Asian horseshoe crab conservation. Despite long-term monitoring across habitat types is lacking, local population declines were widely perceived. Ongoing residential/commercial development along the coast was regarded as the most serious threat. A combination of top-down institutional management and bottom-up stakeholder participation was cited as the most promising strategy. Population and habitat baseline collections should be prioritized in future research to inform conservation planning. In this paper, we summarize the survey findings into the BTPAE (Baseline, Threat, Purpose, Action and Evaluation) framework, which constitutes to our best hope for the future of Asian horseshoe crab conservation.

Horseshoe crabs are a group of marine chelicerates that contain only four extant species, some of which are endangered. Their hemolymph has been widely used in medical applications for endotoxin detection. Nevertheless, there is limited information on the profiles of their hemolymph proteins and their gut microbial diversity. In this study, we performed the first detailed investigation of the hemolymph proteomics and gut microbiota of two Asian horseshoe crabs Tachypleus tridentatus and Carcinoscorpius rotundicauda. Among the identified proteins being cataloged in the juvenile and adult hemolymph, unexpectedly, sesquiterpenoid signaling pathway proteins including Heat shock protein 83 (HSP83), Chd64, and a juvenile hormone binding protein (JHBP) were revealed. This provides evidence for the presence of functional sesquiterpenoid hormonal systems in these marine chelicerates. consumption of certain horseshoe crab species often leads to tetrodotoxin poisoning and the horseshoe crab is thought to possess a tetrodotoxin resistance mechanism. As such, sodium channels were analyzed and found to have critical amino acid residues that are similar to the toxin resistant pufferfish sodium channels. The source of the toxin is unknown so we investigated the gut microbiota, and found that Clostridium and Vibrio were the most dominant bacteria in T. tridentatus and C. rotundicauda, respectively. Together, this study provides a framework for further understanding of sesquiterpenoids and gut microbiota of these marine chelicerates.

Developmental expression of the CD4 gene in mature T cells is controlled by at least four transcriptional control elements: a promoter, two enhancers and a silencer. In this report we use a transgenic approach to study the mechanisms in which these elements interact to convey appropriate tissue- and cell-specific expression at all stages of T cell development. Our data indicate that the control of CD4 gene expression requires the interaction of multiple elements functioning in different combinations at different stages of T cell development. Expression of the CD4 gene in immature CD4+CD8+ thymocytes requires a third enhancer element located in the 3' flanking region of the CD4 gene. Interestingly, the CD4 promoter and proximal/distal enhancers first begin to function at the HSAlo CD69lo H-2Khi CD4 single-positive stage; cells of this phenotype are believed to have survived positive selection. These data indicate that the CD4 promoter and late enhancer elements are induced by positive selection; thus, the final maturation process is an active event that requires the initiation of a novel program of gene expression. [ABSTRACT FROM AUTHOR]

The effects of environmental and nutritional factors on population dynamics and toxin production were examined in Alexandrium catenella, maintained in enriched K media in laboratory cultures. Starting with a density of 50 cell ml-1, the dinoflagellate population typically showed a lag phase and an exponential growth phase which lasted 14 days each, and then entered the stationary phase, with a maximal capacity of 12-18,000 cell ml-1. Population densities showed distinct diurnal patterns, with population growth beginning 2-4hours in darkness. The optimal physical conditions for growth were pH 8.5, salinity of 30-35, temperature of 20-25 deg. C, and photoperiod of 14//10D to 16L/8D. The cell cycle was determined by flow cytometry on synchronized batch cultures maintained at optimal pH, salinity, temperature and under 5 different photoperiod regimes. It was foundthat the G1 phase was timed to end at approximately 3 h after onset of darkness, and the G2/M phase had begun at 4 hours. Nutrient supply markedly affected population growth. Under optimal physical conditions, the optimal concentrations for macronutrients and micronutrients were: NH+-4 0.025-0.2 mM,NO-3 0.22-8.83 mM, glycerophosphate 0.04-0.06 mM, silicate 0.1-0.54 mM; FeEDTA 0.07-0.11 mM; Co 0.1 5M, Cu 0.005-0.04 5M; Mn 0.22-7.2 5M; Mo 0.03-0.6 5M; Se 0.02-0.1 5M; Zn 0.04-1.6 5M; thiamin 0.075-6 5M; vitamin B12 0.0004-0.004 5M; biotin 0.007-0.0155M; EDTA 5-40 5M. The toxin profile of A. catenella was determined by HPLC and found to include in descending order: GTX-4, GTX-3, GTX-1,B2, neosaxitoxin, saxitoxin. Toxin content per cell was highest in cell populations in the early exponential phase. The highest toxin perlitre medium was recorded at 20 deg. C at the beginning of the stationary phase, when cell density was highest and toxin/cell was still relatively high. At 10 deg. C, the cell density was low while the amount of [ABSTRACT FROM AUTHOR]

Background: There is a growing need for interventions that reduce both violence against children and intimate partner violence in low- and middle-income countries. However, few parenting interventions deliberately address this link. We tested the feasibility of a 16-session group-based parenting programme, Parenting for Respectability, in semi-rural Ugandan communities., Methods: This was a pre-post study with parents and their children (N = 484 parents; 212 children)., Results: Pre-post comparisons found large effects for parent-reported reduced harsh parenting (Cohen's f2 = 0.41 overall; f2 = 0.47 (among session attendees); with an overall reduction of 26% for harsh parenting. Session attendees reported higher reductions than non-attendees (p = 0.014), and male caregivers reported higher reductions than female caregivers (p<0.001). Children also reported reduced harsh parenting by attending fathers (f2 = 0.64 overall; f2 = 0.60) and attending mothers (f2 = 0.56 overall; f2 = 0.51); with reduction in harsh parenting ranging between 27% to 29% in the various categories. Overall, spousal violence reduced by 27% (f2 = 0.19 overall; f2 = 0.26 (among session attendees). Both parents and children reported reduced dysfunctional parent relationships; parents: f2 = 0.19 overall; f2 = 0.26 (among session attendees); and children: f2 = 0.35 overall; f2 = 0.32 (for attending parents); with reductions ranging between 22% to 28%. Parents who attended more than 50% of the program reported greater effects on reduced dysfunctional relationships than those who attended less than half of the program (B = -0.74, p = 0.013). All secondary outcomes were improved with f2 ranging between 0.08 and 0.39; and improvements ranging between 6% and 28%., Conclusion: Results suggest the importance of more rigorous testing to determine program effectiveness., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Siu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Oral HIV pre-exposure prophylaxis (PrEP) is highly effective, but alternative delivery options are needed to reach more users. Microarray patches (MAPs), a novel drug-delivery system containing micron-scale projections or "microneedles" that deliver drugs via skin, are being developed to deliver long-acting HIV PrEP and as a multipurpose prevention technology to protect from HIV and unintended pregnancy. We explored whether MAP technology could meet user and health system needs in two African countries., Methods: Researchers in South Africa and Uganda conducted 27 focus group discussions, 76 mock-use exercises, and 31 key informant interviews to explore perceptions about MAPs and specific features such as MAP size, duration of protection, delivery indicator, and health system fit. Participants included young women and men from key populations and vulnerable groups at high risk of HIV and/or unintended pregnancy, including adolescent girls and young women; female sex workers and men who have sex with these women; and men who have sex with men. In Uganda, researchers also recruited young women and men from universities and the community as vulnerable groups. Key stakeholders included health care providers, sexual and reproductive health experts, policymakers, and youth activists. Qualitative data were transcribed, translated, coded, and analyzed to explore perspectives and preferences about MAPs. Survey responses after mock-use in Uganda were tabulated to assess satisfaction with MAP features and highlight areas for additional refinement., Results: All groups expressed interest in MAP technology, reporting perceived advantages over other methods. Most participants preferred the smallest MAP size for ease of use and discreetness. Some would accept a larger MAP if it provided longer protection. Most preferred a protection duration of 1 to 3 months or longer; others preferred 1-week protection. Upper arm and thigh were the most preferred application sites. Up to 30 minutes of wear time was considered acceptable; some wanted longer to ensure the drug was fully delivered. Self-administration was valued by all groups; most preferred initial training by a provider., Conclusions: Potential users and stakeholders showed strong interest in/acceptance of MAP technology, and their feedback identified key improvements for MAP design. If a MAP containing a high-potency antiretroviral or a MAP containing both an antiretroviral and hormonal contraceptive is developed, these products could improve acceptability/uptake of protection options in sub-Saharan Africa., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Ismail et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Introduction: Global and national initiatives have successfully increased access to public education in low- and middle-income countries. However, many students in rural regions in these countries have high rates of absenteeism and drop-out, and low levels of academic engagement. Together, these significantly limit children's academic performance and achievement. One strategy that addresses these barriers seeks to engage members of the wider local community in schools. Most previous research focuses on adults' perspectives even though the potential benefit of community engagement is greatest when learners perceive it to be positive. Past research has also focused on community members structured engagement in activities within schools. This research provides a wider exploration of children's lived experience and perceptions concerning community members' influence on their schooling and learning. The aim was to gain a rich picture of how primary school students in rural Uganda perceive that community members' behavior helps or hinders their education., Methods: Qualitative data from students 10 to 13 years of age were collected through individual interviews that used the draw-and-talk technique ( n = 20) and four focus group discussions., Results: Seven broad categories of community members' actions were perceived to be positive (conflict resolution; supporting students' physical well-being; encouraging learning and positive behavior; reducing truancy; providing food and financial support; collective community work; and political representation). Four categories of community members' actions were perceived to have a negative influence (creating barriers to attending school; noise and other distractions; insecurity; and theft and vandalism)., Discussion: We conclude that carefully structured community involvement in schooling may improve the emotional and material support that facilitates students' continued school attendance and their motivation for learning. However, we also identify some limits on the role that local communities may be able to play in overcoming the challenges facing education in low- and middle-income countries., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Balikoowa, Ojiambo, Emuron, Siu, Mbabazi-Mpyangu, Kikooma, Mugambwa, Nuwagaba, Baluku and Onen.)

Uganda applies the World Health Organization threshold of 1,000 copies/ml to determine HIV viral non-suppression. While there is an emerging concern of low-level viraemia (≥50 to <1,000 copies/ml), there is limited understanding of how people on antiretroviral therapy perceive viral load testing and low-level viremia in resource-limited settings. This qualitative study used the health belief model to explore the meaning that people living with HIV attach to viral load testing and low-level viraemia in Uganda. We used stratified purposive sampling to select people on antiretroviral therapy from eight high volume health facilities from the Central, Eastern, Northern and Western regions of Uganda. We used an interview guide, based on the health belief model, to conduct 32 in-depth interviews, which were audio-recorded and transcribed verbatim. Thematic analysis technique was used to analyze the data with the help of ATLAS.ti 6. The descriptions of viral load testing used by the participants nearly matched the medical meaning, and many people living with HIV understood what viral load testing was. Perceived benefits for viral load testing were the ability to show; the amount of HIV in the body, how the people living with HIV take their drugs, whether the drugs are working, and also guide the next treatments steps for the patients. Participants reported HIV stigma, lack of transport, lack of awareness for viral load testing, delayed and missing viral load results and few health workers as the main barriers to viral load testing. On the contrary, most participants did not know what low-level viraemia meant, while several perceived it as having a reduced viral load that is suppressed. Many people living with HIV are unaware about low-level viraemia, and hence do not understand its associated risks. Likewise, some people living with HIV are still not aware about viral load testing. Lack of transport, HIV stigma and delayed viral load results are major barriers to viral load testing. Hence, there is an imminent need to institute more strategies to create awareness about both low-level viraemia and viral load testing, manage HIV related stigma, and improve turnaround time for viral load results., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Nanyeenya et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

A new labrid fish, Terelabrus toretore sp. nov., the fifth species within the genus, is herein described from two specimens collected at a depth of 140 m from a mesophotic coral ecosystem in Tahiti, French Polynesia. Terelabrus toretore sp. nov. is characterized by having 43-44 scaled rows in longitudinal series; 42 pored lateral-line scales; 5+10 gill rakers; 10 scale rows below the lateral line; 8 posterior branches on the main supratemporal sensory canal; a relatively long snout (snout length 9.6-9.7% SL), and a coloration consisting of a yellow caudal fin and a wide, red, mid-lateral stripe with no blotching, the space above which is white anteriorly, becoming predominantly yellow from beneath the dorsal fin to the caudal peduncle. In addition to describing this new species, we document the first record of Terelabrus rubrovittatus from the Republic of Marshall Islands, and the first record of Terelabrus zonalis from Australia, along with the first description of its coloration. We present a molecular phylogeny of the genus based upon mitochondrial cytochrome c oxidase subunit I ( COI ) DNA sequences.