Motivation, responsibilities, and experiences of HIV/AIDS counselors in the Volta Region of Ghana: a descriptive phenomenological study.

BACKGROUND: The provision of professional counseling services for persons living with human immunodeficiency virus (PLHIV) is crucial in the prevention and treatment continuum of the disease. However, for counselors of people infected with the human immunodeficiency virus (HIV) leading to acquired immune deficiency syndrome (AIDS) to give their best, their motivations to become counselors and the challenges they face in their line of duty need to be contextually understood and addressed. We ascertained the roles, motivations, and experiences of HIV/AIDS counselors in the Volta Region of Ghana to inform HIV/AIDS counseling decision-making in the region and the country. METHODS: A phenomenological study conducted among sixteen (16) HIV/AIDS counselors from five HIV/AIDS sentinel sites in the Volta region of Ghana, recruited through a purposive sampling approach and interviewed to ascertain their HIV/AIDS counseling-related experiences. The data were thematically analyzed using the Atlas. ti software, and sub-themes supported with verbatim quotes. RESULTS: Five motives for becoming an HIV/AIDS counselor were found. These include being randomly assigned to the unit, developing interest in the job, because of the status of a relative, witnessing bad attitudes of healthcare providers, and seeing HIV- clients lacking knowledge of the condition. The study found that these counselors performed six core roles: providing nutritional counseling, educating clients on HIV, treatment, and medication provision, conducting testing and comprehensive counseling of clients, providing social support to clients, and offering financial support to clients. The experiences these counselors had were boosting clients' health status, counseling clients back to a normal mental state, cooperation from clients, participants gaining knowledge on HIV through counseling, counseling clients to accept their status, and when a client delivered an HIV-negative baby. Their negative experiences included clients denying their HIV status, clients defaulting on their treatment, uncooperative clients, death of clients due to fear of breach of confidentiality, self-stigmatization among clients, and the myths some people hold towards HIV/AIDS. CONCLUSION: By organizing capacity-building training programs for HIV/AIDS counselors in the Volta region and addressing the negative experiences they encounter, they could be empowered to provide effective counseling, curative, and social services to people living with HIV in the region, leading to improved health outcomes.

Work-related stress among nurses: a comparative cross-sectional study of two government hospitals in Ghana.

BACKGROUND: Occupational stress is increasing globally and affecting all workplaces and countries' health professionals. Despite its significant impact on healthcare delivery, limited studies have actually compared the prevalence, causes, effects, and coping strategies of stress among nurses working in hospitals with variation in capacity and function in Ghana. We, therefore, examined and compared the prevalence, causes, effects and coping strategies of occupational stress among nurses working in a secondary care and tertiary hospital in Ghana. METHODS: We conducted a health facility-based cross-sectional study among 248 nurses from two hospitals (Volta Regional Hospital [VRH] and Ho Teaching Hospital [HTH]). The Perceived Stress Scale (PSS) and Weiman Occupational Stress Scale (WOSS) were used to measure the nurses' stress levels and causes of occupational stress respectively. A self-reported checklist was used to measure both the effects of stress and strategies. Descriptive analyses and t-tests were performed, and statistical significance was measured at the 0.05 level. RESULTS: The majority of nurses 77.8% experienced a moderate level of perceived stress. The total individual mean scores of the nurses from the two hospitals (VRH = 3.02 and HTH = 3.09) were 34% and 37% respectively higher than the established WOSS individual average of 2.25. Nursing difficult patients (t=-1.1196, p = 0.037), Unfriendly relationships with superiors, colleagues, and subordinates (t=-2.3333, p = 0.020), working with incompetent staff (t=-1.3129, p = 0.037) were the statistically significant stressors among nurses in the HTH. Whereas, long work hours (t = 2.0841, p = 0.038) and needle-stick injuries (t = 2.6669, p = 0.008) were the statistically significant stressors among nurses from the VRH. Headache (VRH = 73.8% and HTH = 97.9%), Fatigue (VRH = 68.9% and HTH = 83.5%), Frustration VRH = 50.5% and HTH = 68.3%) and Lack of Concentration (VRH = 81.6% and HTH = 80.0%) were most common effects of occupational stress reported. CONCLUSION: The majority of nurses reported moderate levels of stress, with the two institutions' stressors differing. Key causes of stress were needle stick injuries, long hours, dealing with challenging patients and strained interpersonal relationships. Common side effects were headaches, exhaustion, irritability, and trouble focusing. To accelerate progress towards achieving the sustainable development goal (SDG) 3.4 of promoting mental health and well-being by 2030, the 2012 Mental Health Act of Ghana and the Occupational Health and Safety Regulations, should fully and effectively be implemented in health facilities across the country.

Betting high, feeling low: a cross-sectional examination of gambling severity and psychological distress among Ghanaian youth.

BACKGROUND: Little is known about the nexus between online gambling and psychological distress among youth, especially in Ghana. This study aimed to investigate the effects of online sports betting on psychological distress, focusing on depression, anxiety, and stress among young individuals in the Volta region of Ghana. METHODS: A cross-sectional study was carried out at various betting centers in the Volta region of Ghana. Four hundred and three (403) participants were selected using a multi-stage sampling method. The study used a standardized questionnaire to assess psychological distress with the Depression, Anxiety, and Stress Scale (DASS 21) and problematic gambling with the Problem Gambling Severity Index (PGSI). The analysis included both descriptive and inferential methods. These include the implementation of the bootstrap technique within multiple regression models using the current versions of Jeffreys's Amazing Statistics Program (JASP) [0.18.2], Statistical Package for the Social Sciences (SPSS) [29.0.2], and Microsoft Excel (2019). RESULTS: The study found a prevalence of 40% for problematic gambling and 44% for moderate gambling problems among participants, resulting in an overall gambling prevalence of 84%. Regarding psychological distress, the estimated prevalence of depression among participants was 43.6%, with stress reported at 31.1% and anxiety at 68.8%. The overall prevalence of psychological distress was 48%. When analyzing the link between gambling and psychological distress, the study noted that males were more prone to gambling-related psychological distress than females (ß = 2.036, p = 0.025). Furthermore, individuals with problem gambling showed the highest probability of experiencing more significant psychological distress compared to other groups (ß = 9.228, p = 0.002), followed by those with moderate gambling levels (ß = 3.283, p = 0.002). CONCLUSION: We recommend that the mental health unit of the Ghana Health Service, in collaboration with the Gaming Commission of Ghana, should develop youth-friendly interventions to address the prevalence and onset of problematic gambling among the youth, especially males. This could, in turn, reduce the prevalence of psychological distress among youth engaged in online gambling in Ghana.

Evaluating groundwater resources trends through multiple conceptual models and GRACE satellite data.

In this research, three numerical groundwater flow models, developed and calibrated from three equally plausible conceptual models over the Nasia Basin, have been used to assess groundwater resources variations over a transient period. The use of multiple numerical models reduces the effect of uncertainties in conceptual model formulation. All the three calibrated numerical models indicate an increasing trend of groundwater recharge and storage over the period of the groundwater level monitoring. This suggests that the prevailing erratic climatic conditions in the area are conducive for increasing groundwater recharge and storage in the terrain. The high-intensity, short duration rainfall patterns, attending climate change in the basin, enhance high levels of infiltration and percolation, leading to steadily increasing groundwater recharge. Groundwater recharge estimates from each of the models over the transient period appear to reflect the pattern of seasonal variations in rainfall in the region. Data from the models indicates a significant role of baseflow in sustaining perennial streamflow in the area. This presents a significant development in terms of groundwater-based adaptation projects, especially in agriculture. The trend of groundwater recharge in the Nasia Basin is in sync with regional groundwater storage variations estimated from the Gravity Recovery and Climate Experiment (GRACE) satellite data collected and processed over the Volta Basin. At the Volta Basin level, groundwater storage variations indicate a strong positive trend of increasing groundwater recharge from 2002 (beginning of the GRACE mission) to 2022 (end point of the data used for this research). Analysis of the GRACE data suggests that there is a cumulative increase in groundwater storage by 30 cm, representing approximately 120 km3 of groundwater over the period in the basin. This translates into approximately 15 mm/year of groundwater storage increase. Thus, at both the regional and local levels, groundwater appears to be responding positively to the impacts of erratic rainfall patterns observed in the area recently. The high-intensity, short duration rainfall patterns appear to favor significant groundwater recharge, resulting in a strong positive groundwater storage signal. The high positive groundwater storage signal suggests increasing groundwater resources potential in the area, indicating promising opportunities for groundwater-based climate change adaptation interventions.

Dual-axis Volta phase plate cryo-electron tomography of Ebola virus-like particles reveals actin-VP40 interactions.

Cryo-electron tomography (cryo-ET) is a pivotal imaging technique for studying the structure of pleomorphic enveloped viruses and their interactions with the host at native conditions. Owing to the limited tilting range of samples with a slab geometry, electron tomograms suffer from so-called missing wedge information in Fourier space. In dual-axis cryo-ET, two tomograms reconstructed from orthogonally oriented tilt series are combined into a tomogram with improved resolution as the missing wedge information is reduced to a pyramid. Volta phase plate (VPP) allows to perform in-focus cryo-ET with high contrast transfer at low-resolution frequencies and thus its application may improve the quality of dual-axis tomograms. Here, we compare dual-axis cryo-ET with and without VPP on Ebola virus-like particles to visualize and segment viral and host cell proteins within the membrane-enveloped filamentous particles. Dual-axis VPP cryo-ET reduces the missing wedge information and ray artifacts arising from the weighted back-projection during tomogram reconstruction, thereby minimizing ambiguity in the analysis of crowded environments and facilitating 3D segmentation. We show that dual-axis VPP tomograms provide a comprehensive description of macromolecular organizations such as nucleocapsid assembly states, the distribution of glycoproteins on the viral envelope and asymmetric arrangements of the VP40 layer in non-filamentous regions of virus-like particles. Our data reveal actin filaments within virus-like particles in close proximity to the viral VP40 scaffold, suggesting a direct interaction between VP40 and actin filaments. Dual-axis VPP cryo-ET provides more complete 3D information at high contrast and allows for better interpretation of macromolecule interactions and pleomorphic organizations.

Annual and intra-annual climate variability and change of the Volta Delta, Ghana.

Deltas are geographically and socio-ecologically distinct systems, with a unique climate and contextually high vulnerabilities to climate dynamics. Hence, they require specific climate change adaptation and policy responses, informed by delta-scale analysis. However, available climate knowledge on deltas is based mainly on broad-scale analysis that masks information unique to deltas. This applies to the Volta Delta system of Ghana. This study presents annual and intra-annual climate variability and trend analysis carried out across the Volta Delta, using the coefficient of variation (CV), anomaly, Mann-Kendall and Pettit statistics. There were time and space differences in climate change and variability. Statistically significant (P < 0.05) positive trends were observed for the major wet season and the mean annual rainfall for Ada and highly significant (P < 0.01) positive trends for Akatsi. These contrasted with the observations in Adidome, which experienced a statistically highly significant (P < 0.01) decreasing trend in rainfall. There were significant (P< 0.05) increases in annual minimum, maximum, and mean temperatures over time in both coastal and inland delta stations. The annual rate of change of mean temperature ranged from 0.03 to 0.05. Ada, the more coastal location, has experienced a narrow range of temperature change, most probably due to the buffering capacity of the ocean. Point changes were observed in the climate data series in four (4) localities. We recommend that adaption and policy actions should include, the provision of small-scale irrigation, encouraging adoption of drought-resistant crop varieties and crop diversification, and also be made responsive to the existing spatiotemporal climate variability and change within the Volta Delta.

Cryo-EM structures of cardiac thin filaments reveal the 3D architecture of troponin.

Troponin is an essential component of striated muscle and it regulates the sliding of actomyosin system in a calcium-dependent manner. Despite its importance, the structure of troponin has been elusive due to its high structural heterogeneity. In this study, we analyzed the 3D structures of murine cardiac thin filaments using a cryo-electron microscope equipped with a Volta phase plate (VPP). Contrast enhancement by a VPP enabled us to reconstruct the entire repeat of the thin filament. We determined the orientation of troponin relative to F-actin and tropomyosin, and characterized the interactions between troponin and tropomyosin. This study provides a structural basis for understanding the molecular mechanism of actomyosin system.

Prevalence of sickle cell disorders and malaria infection in children aged 1-12 years in the Volta Region, Ghana: a community-based study.

BACKGROUND: Alterations in the structure of haemoglobin (Hb) are usually brought about by point mutations affecting one or, in some cases, two codons encoding amino acids of the globin chains. One in three Ghanaians are said to have sickle cell disorders, whereas malaria continues to be one of the leading causes of mortality among children. This study determined the prevalence of sickle cell disorders and malaria infection among children aged 1-12 years in the Volta Region. METHODS: This was a community-based cross-sectional survey that involved 938 children aged 1-12 years selected from three districts, one each from the 3 geographical zones of the Volta Region using a multistage sampling method. Demographic information was collected using a standard questionnaire and anthropometric indices were measured. Isoelectric focusing (IEF) electrophoresis was used to determine the Hb genotypes and sub-microscopic parasites were determined by PCR. RESULTS: The prevalence of sickling screening positive was 16.0% with an overall prevalence of sickle cell disorders being 2.0%. Among the individual genotypes making up the sickle cell disorders, genotype HbSF was the highest (0.9% as compared to 0.2%; HbSS, 0.6%; HbSC and 0.3%; HbSCF). Microscopic Plasmodium falciparum parasitaemia was detected among 5.5% of the children and 14.2% sub-microscopic prevalence by PCR. Children with sickle cell disorders were more likely to have sub-microscopic parasitaemia (AOR = 5.51 95%CI (2.15, 14.10), p < 0.001) as well as anaemia (AOR = 3.03 95% CI (1.04, 8.82), p = 0.042), compared to those with normal genotypes. There was no significant difference observed between sickle cell disorders and growth and development of the children screened. CONCLUSIONS: Sickle cell disorders were significantly associated with sub-microscopic parasitaemia as well as anaemia in this study. Establishment of sickle cell clinics in the district and regional hospitals will help in the management of children with the disorder and also generate a national database on sickle cell disorders. National neonatal screening policies must also be put in place to help in early detection and management of these disorders.

Potential health risk assessment of toxic metals contamination in clay eaten as pica (geophagia) among pregnant women of Ho in the Volta Region of Ghana.

INTRODUCTION: Geophagia although pleasurable and somewhat a necessity among pregnant women, also comes along with its own attendant problems such as exposure to potentially hazardous substances like bacteria, fungi, helminthes and ova, radioactive materials, and toxic elemental minerals in the soil depending on the geographical location. METHODOLOGY: This study evaluated the potential health risk involved during the exposure of pregnant women to toxic elemental minerals via the consumption of clay as pica (geophagia). Elemental mineral analysis was carried out using Buck Scientific 210VGP Flame Atomic Absorption Spectrophotometer (Buck Scientific, Inc. East Norwalk, USA). Risk assessment methods were also used to ascertain the various risks factors and the overall risk level. RESULTS: Concentrations of the macro elements investigated were 1.38 ± 1.5, 2.40 ± 1.5, 7.74 ± 1.5, 4.01 ± 1.0, 13.24 ± 2.2 and 13.76 ± 2.1 mg/Kg for iron (Fe), copper (Cu), zinc (Zn), potassium (K), magnesium (Mg) and sodium (Na) respectively. While that for the micro elements were 1.63 ± 0.03 µg/Kg, 4.72 ± 0.8, 0.53 ± 0.02 and 1.85 ± 0.3 mg/kg respectively for arsenic (As), manganese (Mn), lead (Pb) and nickel (Ni). Estimated Daily Intake (EDI), Hazard Quotient (HQ), Target Hazard Quotient (THQ) and Total Target Hazard Quotient (TTHQ) values ranged 0.611-5.44 (mg/kg Bw/day), 6.26 × 10- 4 - 106.5, 0.067-10.34 and 15 respectively. CONCLUSION: There is the likelihood of posing adverse health problems when clay samples obtained from Anfoega which is sited in the Volta region of Ghana is consumed due to the fact that the HQ's of these elemental minerals were > 1 which points to high content of Manganese (Mn) and Nickel (Ni). It is also likely to cause adverse health problems in an individual's life time since THQ for Arsenic, Lead and Nickel were above 1. Ultimately, the cumulative effect of these toxicants were exceedingly great (≤ 15) which implied a high level of unsafety associated with this clay. Per the results from this study, it is not safe for pregnant women to consume clay as pica since these toxic elements may cause detrimental effects on the foetus of the unborn child.

Community utilisation and satisfaction with the community-based health planning and services initiative in Ghana: a comparative study in two system learning districts of the CHPS+ project.

BACKGROUND: To strengthen the implementation of the Community-based Health Planning and Services (CHPS) programme which is Ghana's key primary health care delivery strategy, the CHPS+ Project was initiated in 2017. We examined community utilisation and satisfaction with CHPS services in two System Learning Districts (SLDs) of the project. METHODS: This community-based descriptive study was conducted in the Nkwanta South Municipality and Central Tongu District of Ghana. Data were collected from 1008 adults and analysed using frequency, percentage, chi-square, and logistic regression models. RESULTS: While the level of utilisation of CHPS services was 65.2%, satisfaction was 46.1%. Utilisation was 76.7% in Nkwanta South and 53.8% in Central Tongu. Satisfaction was also 55.2% in Nkwanta South and 37.1% in Central Tongu. Community members in Nkwanta South were more likely to utilise (AOR = 3.17, 95%CI = 3.98-9.76) and be satisfied (AOR = 2.77, 95%CI = 1.56-4.90) with CHPS services than those in Central Tongu. Females were more likely to utilise (AOR = 1.75, 95%CI = 1.27-2.39) but less likely to be satisfied [AOR = 0.47, 95%CI = 0.25-0.90] with CHPS services than males. Even though subscription to the National Health Insurance Scheme (NHIS) was just 46.3%, NHIS subscribers were more likely to utilise (AOR = 1.51, 95%CI = 1.22-2.03) and be satisfied (AOR = 1.45, 95%CI = 0.53-1.68) with CHPS services than non-subscribers. CONCLUSION: Ghana may not be able to achieve the goal of universal health coverage (UHC) by the year 2030 if current levels of utilisation and satisfaction with CHPS services persist. To accelerate progress towards the achievement of UHC with CHPS as the vehicle through which primary health care is delivered, there should be increased public education by the Ghana Health Service (GHS) on the CHPS concept to increase utilisation. Service quality should also be improved by the GHS and other stakeholders in Ghana's health industry to increase satisfaction with CHPS services. The GHS and the National Health Insurance Authority (NHIA) should also institute innovative strategies to increase subscription to the NHIS since it has implications for CHPS service utilisation and satisfaction.

Morphologies of synaptic protein membrane fusion interfaces.

Neurotransmitter release is orchestrated by synaptic proteins, such as SNAREs, synaptotagmin, and complexin, but the molecular mechanisms remain unclear. We visualized functionally active synaptic proteins reconstituted into proteoliposomes and their interactions in a native membrane environment by electron cryotomography with a Volta phase plate for improved resolvability. The images revealed individual synaptic proteins and synaptic protein complex densities at prefusion contact sites between membranes. We observed distinct morphologies of individual synaptic proteins and their complexes. The minimal system, consisting of neuronal SNAREs and synaptotagmin-1, produced point and long-contact prefusion states. Morphologies and populations of these states changed as the regulatory factors complexin and Munc13 were added. Complexin increased the membrane separation, along with a higher propensity of point contacts. Further inclusion of the priming factor Munc13 exclusively restricted prefusion states to point contacts, all of which efficiently fused upon Ca2+ triggering. We conclude that synaptic proteins have evolved to limit possible contact site assemblies and morphologies to those that promote fast Ca2+-triggered release.

In situ structural studies of tripeptidyl peptidase II (TPPII) reveal spatial association with proteasomes.

Tripeptidyl peptidase II (TPPII) is a eukaryotic protease acting downstream of the 26S proteasome; it removes tripeptides from the degradation products released by the proteasome. Structural studies in vitro have revealed the basic architecture of TPPII, a two-stranded linear polymer that assembles to form a spindle-shaped complex of ∼6 MDa. Dependent on protein concentration, TPPII has a distinct tendency for polymorphism. Therefore, its structure in vivo has remained unclear. To resolve this issue, we have scrutinized cryo-electron tomograms of rat hippocampal neurons for the occurrence and spatial distribution of TPPII by template matching. The quality of the tomograms recorded with the Volta phase plate enabled a detailed structural analysis of TPPII despite its low abundance. Two different assembly states (36-mers and 32-mers) coexist as well as occasional extended forms with longer strands. A distance analysis of the relative locations of TPPII and 26S proteasomes confirmed the visual impression that these two complexes spatially associate in agreement with TPPII's role in postproteasomal degradation.

Sub-3 Šapoferritin structure determined with full range of phase shifts using a single position of volta phase plate.

Volta Phase Plate (VPP) has become an invaluable tool for cryo-EM structural determination of small protein complexes by increasing image contrast. Currently, the standard protocol of VPP usage periodically changes the VPP position to a fresh spot during data collection. Such a protocol was to target the phase shifts to a relatively narrow range (around 90°) based on the observations of increased phase shifts and image blur associated with more images taken with a single VPP position. Here, we report a 2.87 Šresolution structure of apoferritin reconstructed from a dataset collected using only a single position of VPP. The reconstruction resolution and map density features are nearly identical to the reconstruction from the control dataset collected with periodic change of VPP positions. Further experiments have verified that similar results, including a 2.5 Šresolution structure, could be obtained with a full range of phase shifts, different spots of variable phase shift increasing rates, and at different ages of the VPP post-installation. Furthermore, we have found that the phase shifts at low resolutions, probably related to the finite size of the Volta spots, could not be correctly modeled by current CTF model using a constant phase shift at all frequencies. In dataset III, severe beam tilt issue was identified but could be computationally corrected with iterative refinements. The observations in this study may provide new insights into further improvement of both the efficiency and robustness of VPP, and to help turn VPP into a plug-and-play device for high-resolution cryo-EM.

Mapping Ecosystem Services to Human Well-being: a toolkit to support integrated landscape management for the SDGs.

The Sustainable Development Goals (SDGs) emphasize the global and multi-dimensional nature of sustainability and thus require improving our capacity to articulate and trace the impact of ecosystem change to measures of human well-being. Yet, the integrated nature of these goals is challenging to assess without similarly integrated assessment tools. We present a new modeling toolkit, "Mapping Ecosystem Services to Human well-being" (MESH), that integrates commonly used, stand-alone ecosystem services (ES) models from the InVEST suite of models to quantify and illustrate the trade-offs and synergies across five ecosystem services and up to 10 associated SDGs. Development of the software and its functionality were informed by a broad stakeholder consultation with ministries, non-governmental organizations and civil society groups in West Africa to identify common barriers to uptake and application of modeling tools in developing countries. In light of this process, key features included in MESH are (1) integration of multiple ecosystem service (ES) models into a common modeling framework supported by a curated base data set, (2) built-in scenario generation capacity to support policy analysis, (3) visualization of outcomes and trade-offs, and (4) mapping of ecosystem service change to SDG targets and goals. We illustrate the use of MESH in a case study in the Volta basin of West Africa comparing the effectiveness of three alternative conservation prioritization approaches: (1) land cover-based, (2) topographic-based, and (3) an ecosystem service-based approach to minimize the impact of agricultural expansion. We evaluate these approaches by linking changes in service supply to potential impacts on achievement of specific SDG goals and targets.

Factors influencing adherence to the new intermittent preventive treatment of malaria in pregnancy policy in Keta District of the Volta region, Ghana.

BACKGROUND: About 25% of pregnant women in malaria-endemic areas are infected with malaria and this accounts for about 15% of maternal deaths globally. Intermittent preventive treatment in pregnancy with sulfadoxine-pyrimethamine (IPTp-SP) is one of the main strategies for prevention of malaria in pregnancy. A new recommendation was made by the World Health Organization (WHO) that at least three doses of IPTp-SP should be administered before delivery. This study sought to determine the factors influencing adherence to the new IPTp-SP policy in Keta District, Volta region, Ghana. METHODS: A cross-sectional quantitative study among 375 nursing mothers at four selected health facilities in Keta district, Ghana was conducted using a structured questionnaire to interview participants. Sampling proportionate to the size of facility was used to determine the number of nursing mothers from each facility based on the caseload. For each facility systematic random sampling was used to select eligible nursing mothers. Data was analyzed using STATA 15. Chi-square was used to test bivariate association between categorical variables and adherence. Logistic regression analysis was used to examine sociodemographic, individual and institutional factors influencing adherence to IPTp-SP. RESULT: About 82.1% of participants adhered to the WHO policy recommendations of at least three doses of IPTp-SP. However, only 17.1% received Ghana's five dose coverage recommendation. The proportion of IPTp-SP coverage for IPTp1 was 98.9%; IPTp2 95.5%; IPTp3 80.8%; IPTp4 39.5%; IPTp5 17.1%. CONCLUSION: Adherence to IPTp-SP was satisfactory according to WHO's policy recommendation, however, majority of the participants had less than the five doses recommended in Ghana. Number of Antenatal Care (ANC) visits and knowledge of malaria were the main determinants of adherence to IPTp-SP.

Volta Phase Plate Cryo-EM Structure of the Human Heterodimeric Amino Acid Transporter 4F2hc-LAT2.

Heteromeric amino acid transporters (HATs) are protein complexes that catalyze the transport of amino acids across plasma membranes. HATs are composed of two subunits, a heavy and a light subunit, which belong to the solute carrier (SLC) families SLC3 and SLC7. The two subunits are linked by a conserved disulfide bridge. Several human diseases are associated with loss of function or overexpression of specific HATs making them drug targets. The human HAT 4F2hc-LAT2 (SLC3A2-SLC7A8) is specific for the transport of large neutral L-amino acids and specific amino acid-related compounds. Human 4F2hc-LAT2 can be functionally overexpressed in the methylotrophic yeast Pichia pastoris and pure recombinant protein purified. Here we present the first cryo-electron microscopy (cryo-EM) 3D-map of a HAT, i.e., of the human 4F2hc-LAT2 complex. The structure could be determined at ~13 Å resolution using direct electron detector and Volta phase plate technologies. The 3D-map displays two prominent densities of different sizes. The available X-ray structure of the 4F2hc ectodomain fitted nicely into the smaller density revealing the relative position of 4F2hc with respect to LAT2 and the membrane plane.

Strange Case of Signor Volta and Mister Nicholson: How Electrochemistry Developed as a Consequence of an Editorial Misconduct.

This Essay tells the colourful history of the invention of the pile by Alessandro Volta and of the subsequent discovery by William Nicholson of the electrolysis of water, carried out with the Voltaic pile (1800). Indeed, as a result of the dissemination of Volta's paper among London scientists, favoured by an incorrect behaviour of the President of the Royal Society, the article by Nicholson was published months before the publication of Volta's letter. The outstanding news that electricity could be generated by a simple and easy to build instrument (the pile) was printed also by daily newspapers, which favoured its spreading all over Europe and stimulated a multitude of enthusiast practitioners and amateurs to construct their own pile and to carry out the electrical decomposition of a variety of aqueous electrolytes. The correct chemical interpretation of the pile and of electrolysis had to wait for nearly one century, but in 1800 electrochemistry was born.

Volta phase plate data collection facilitates image processing and cryo-EM structure determination.

A current bottleneck in structure determination of macromolecular complexes by cryo electron microscopy (cryo-EM) is the large amount of data needed to obtain high-resolution 3D reconstructions, including through sorting into different conformations and compositions with advanced image processing. Additionally, it may be difficult to visualize small ligands that bind in sub-stoichiometric levels. Volta phase plates (VPP) introduce a phase shift in the contrast transfer and drastically increase the contrast of the recorded low-dose cryo-EM images while preserving high frequency information. Here we present a comparative study to address the behavior of different data sets during image processing and quantify important parameters during structure refinement. The automated data collection was done from the same human ribosome sample either as a conventional defocus range dataset or with a Volta phase plate close to focus (cfVPP) or with a small defocus (dfVPP). The analysis of image processing parameters shows that dfVPP data behave more robustly during cryo-EM structure refinement because particle alignments, Euler angle assignments and 2D & 3D classifications behave more stably and converge faster. In particular, less particle images are required to reach the same resolution in the 3D reconstructions. Finally, we find that defocus range data collection is also applicable to VPP. This study shows that data processing and cryo-EM map interpretation, including atomic model refinement, are facilitated significantly by performing VPP cryo-EM, which will have an important impact on structural biology.

Subtomogram analysis using the Volta phase plate.

Cryo-electron tomography (CET) and subtomogram analysis allow studying the structures of macromolecular complexes in their natural context. The radiation sensitivity of vitrified biological specimens and the resulting low signal-to-noise ratio (SNR) in CET limit the amount of structural information that can be mined from tomographic data. The Volta phase plate (VPP) has emerged as an effective means to increase the SNR and hence contrast compared to 'conventional' defocus-based phase contrast transmission electron microscopy (CTEM). Here, we assess the performance of the VPP compared to CTEM in subtomogram analysis, using the mammalian 80S ribosome as a test case. Accurate focusing is the major factor for achieving high resolution with the VPP, as highlighted by a comparison of slightly different focusing strategies. From only 1400 subtomograms, the VPP yields a subtomogram average of the mammalian 80S ribosome at 9.6Å resolution without laborious contrast transfer function (CTF) correction. The subtomogram averages obtained using CTEM approaches are comparable, but suffer from lower signal transfer in certain frequency bands due to the oscillations of the CTF. Our study demonstrates that the VPP is a valuable tool for subtomogram analysis, because it enables improved performance and efficiency in terms of structure localization and number of subtomograms required for a given resolution.

Optimized cryo-focused ion beam sample preparation aimed at in situ structural studies of membrane proteins.

While cryo-electron tomography (cryo-ET) can reveal biological structures in their native state within the cellular environment, it requires the production of high-quality frozen-hydrated sections that are thinner than 300nm. Sample requirements are even more stringent for the visualization of membrane-bound protein complexes within dense cellular regions. Focused ion beam (FIB) sample preparation for transmission electron microscopy (TEM) is a well-established technique in material science, but there are only few examples of biological samples exhibiting sufficient quality for high-resolution in situ investigation by cryo-ET. In this work, we present a comprehensive description of a cryo-sample preparation workflow incorporating additional conductive-coating procedures. These coating steps eliminate the adverse effects of sample charging on imaging with the Volta phase plate, allowing data acquisition with improved contrast. We discuss optimized FIB milling strategies adapted from material science and each critical step required to produce homogeneously thin, non-charging FIB lamellas that make large areas of unperturbed HeLa and Chlamydomonas cells accessible for cryo-ET at molecular resolution.