Moving towards social inclusion: Engaging rural voices in priority setting for health

BACKGROUND

Achieving universal health coverage (UHC) in the context of limited resources will require prioritising the most vulnerable and ensuring health policies and services are responsive to their needs. One way of addressing this is through the engagement of marginalised voices in the priority setting process. Public engagement approaches that enable group level deliberation as well as individual level preference capturing might be valuable in this regard, but there are limited examples of their practical application, and gaps in understanding their outcomes, especially with rural populations.

OBJECTIVE

To address this gap, we implemented a modified priority setting tool (Choosing All Together-CHAT) that enables individuals and groups to make trade-offs to demonstrate the type of health services packages that may be acceptable to a rural population. The paper presents the findings from the individual choices as compared to the group choices, as well as the differences among the individual choices using this tool.

METHODS

Participants worked in groups and as individuals to allocate stickers representing the available budget to different health topics and interventions using the CHAT tool. The allocations were recorded at each stage of the study. We calculated the median and interquartile range across study participants for the topic totals. To examine differences in individual choices, we performed Wilcoxon rank sum tests.

RESULTS

The results show that individual interests were mostly aligned with societal ones, and there were no statistically significant differences between the individual and group choices. However, there were some statistically significant differences between individual priorities based on demographic characteristics like age.

DISCUSSION

The study demonstrates that giving individuals greater control and agency in designing health services packages can increase their participation in the priority setting process, align individual and community priorities, and potentially enhance the legitimacy and acceptability of priority setting. Methods that enable group level deliberation and individual level priority setting may be necessary to reconcile plurality. The paper also highlights the importance of capturing the details of public engagement processes and transparently reporting on these details to ensure valuable outcomes.

PUBLIC CONTRIBUTION

The facilitator of the CHAT groups was a member from the community and underwent training from the research team. The fieldworkers were also from the community and were trained and paid to capture the data. The participants were all members of the rural community- the study represents their priorities.

Decomposing consumer and producer effects on sugar from beverage purchases after a sugar-based tax on beverages in South Africa

Growing global concern about obesity and diet-related non-communicable diseases has raised interest in fiscal policy as a tool to reduce this disease burden and its social costs, especially excise taxes on sugar-sweetened beverages (SSBs). Of particular interest have been nutrient-based taxes to improve diet quality. These can incentivize producers to reformulate existing products and introduce healthier alternatives into their ranges. In 2018, South Africa adopted a sugar-based tax on SSBs, the Health Promotion Levy (HPL). Early findings suggest that purchases of higher-sugar taxable beverages fell and purchases of no- and lower-sugar beverages increased, alongside significant reductions in the sugar content of overall beverage purchases. However, underlying these changes are consumption shifts as well as product reformulation and changes in producers' product portfolios. Drawing on a household scanner dataset, this study employed a descriptive approach to decompose changes in the sugar content of households' non-alcoholic beverage purchases into producer factors (reformulation and product entry and exit) and consumer factors (product switching and volume changes as a result of price changes, changing preferences, or other factors). We look at these factors as the tax was announced and implemented across a sample of over 3000 South African households, and then by Living Standard Measures (LSM) groups (middle vs. high). The sugar content of beverage purchases fell by 4.9 g/capita/day overall, a 32% decrease. Taken in isolation, consumer switching and volume changes together led to a reduction equivalent to 71% of the total change, while reformulation accounted for a decrease equal to 34% of that change. Middle-LSM households experienced larger reductions than high-LSM households due to larger changes on the consumer side. For both LSM groups, reformulation-led reductions mostly occurred after implementation, and most changes came from taxable beverage purchases. As sugary drink tax designs evolve with broader implementation globally, understanding both supply- and demand-side factors will help to better assess the population and equity potential of these policies.

Foregone Health Care During the COVID-19 Pandemic: Early Survey Estimates from 39 Low- and Middle-Income Countries

In addition to the direct health effects of the COVID-19 pandemic, the pandemic has increased the risks of foregone non-COVID-19 health care. Likely, these risks are greatest in low- and middle-income countries (LMICs), where health systems are less resilient and economies more fragile. However, there are no published studies on the prevalence of foregone health care during the pandemic in LMICs. We used pooled data from phone surveys conducted between April and August 2020, covering 73,638 households in 39 LMICs. We estimated the prevalence of foregone care and the relative importance of various reported reasons for foregoing care, disaggregated by country-income group and region. In the sample, 18·8% (95% CI 17·8%-19·8%) of households reported not being able to access health care when needed. Financial barriers were the most-commonly self-reported reason for foregoing care, cited by 31·4% (28·6%-34·3%) of households. More households in wealthier countries reported foregoing care for reasons related to COVID-19 ((27·2% [22·5%-31·8%] in upper middle-income countries compared to 8·0% [4·7%-11·3%] in low-income countries); more households in poorer countries reported foregoing care due to financial reasons (65·6% [59·9%-71·2%]) compared to 17·4% [13·1%-21·6%] in upper middle-income countries. A substantial proportion of households in LMICs had to forgo health care in the early months of the pandemic. While in richer countries this was largely due to fear of contracting COVID-19 or lockdowns, in poorer countries foregone care was due to financial constraints.

South Africa's Health Promotion Levy: Excise tax findings and equity potential

In 2016, the South African government proposed a 20% sugar-sweetened beverage (SSB) tax. Protracted consultations with beverage manufacturers and the sugar industry followed. This resulted in a lower sugar-based beverage tax, the Health Promotion Levy (HPL), of approximately 10% coming into effect in April 2018. We provide a synthesis of findings until April 2021. Studies show that despite the lower rate, purchases of unhealthy SSBs and sugar intake consumption from SSBs fell. There were greater reductions in SSB purchases among both lower socioeconomic groups and in subpopulations with higher SSB consumption. These subpopulations bear larger burdens from obesity and related diseases, suggesting that this policy improves health equity. The current COVID-19 pandemic has impacted food and nutritional security. Increased pandemic mortality among people with obesity, diabetes, and hypertension highlight the importance of intersectoral public health disease-prevention policies like the HPL, which should be strengthened.

Facility standards and the quality of public sector primary care: Evidence from South Africa's "Ideal Clinics" program

Primary healthcare systems are central to achieving universal healthcare coverage. However, in many low- and middle-income country settings, primary care quality is challenged by inadequate facility infrastructure and equipment, limited human resources, and poor provider process. We study the effects of a recent large-scale quality improvement policy in South Africa, the Ideal Clinics Realization and Maintenance Program (ICRMP). The ICRMP introduced a set of standards for facilities and a quality improvement process involving manuals, district-based support, and external assessment. Exploiting differential prioritization of facilities for the ICRMP's quality improvement process, we apply differences-in-differences methods to identify the effects of the program's efforts on standards scores and primary care quality indicators over the first 12 months of implementation. We find large and statistically significant increases in standards scores, but mixed effects on care outcomes-a small magnitude improvement in early antenatal care usage, null effects on childhood immunization and cervical cancer screening, and small negative effect of human immunodeficiency virus (HIV) care. While the ICRMP process has led to significant improvements in facilities' satisfaction of the program's standards, we were unable to detect meaningful change in care quality indicators.

The potential health and revenue effects of a tax on sugar sweetened beverages in Zambia

The global burden of non-communicable diseases (NCDs) has been rising. A key risk factor for NCDs is obesity, which has been partly linked to consumption of sugar sweetened beverages (SSBs). A tax on SSBs is an attractive control measure to curb the rising trend in NCDs, as it has the potential to reduce consumption of SSBs. However, studies on the potential effects of SSB taxes have been concentrated in high-income countries with limited studies in low-income and middle-income countries. Using data from the 2015 Zambia Living Conditions Monitoring Survey (LCMS) data, the 2017 Zambia NCD STEPS Survey, and key parameters from the literature, we simulated the effect of a 25% SSB tax in Zambia on energy intake and the corresponding change in body mass index (BMI), obesity prevalence, deaths averted, life years gained and revenues generated using a mathematical model developed using Microsoft Excel. We conducted Monte Carlo simulations to construct 95% confidence bands and sensitivity analyses to account for uncertainties in key parameters. We found that a 25% SSB would avert 2526 deaths, though these results were not statistically significant overall. However, when broken down by gender, the tax was found to significantly avert 1133 deaths in women (95% CI 353 to 1970). The tax was found to potentially generate an additional US$5.46 million (95% CI 4.66 to 6.14) in revenue annually. We conclude that an SSB tax in Zambia has the potential to significantly decrease the amount of disability-adjusted life years lost to lifestyle-related diseases in women, highlighting important health equity outcomes. Women have higher baseline BMI and therefore are at higher risk for NCDs. In addition, an SSB tax will provide government with additional revenue which if earmarked for health could contribute to healthcare financing in Zambia.

Changes in beverage purchases following the announcement and implementation of South Africa's Health Promotion Levy: an observational study

BACKGROUND

In 2016, South Africa announced an intention to levy a tax on sugar-sweetened beverages (SSBs). In 2018, the country implemented an SSB tax of approximately 10%, known as the Health Promotion Levy (HPL). We aimed to assess changes in the purchases of beverages before and after the HPL announcement and implementation.

METHODS

We used Kantar Europanel data on monthly household purchases between January, 2014, and March, 2019, among a sample of South African households (n=113 653 household-month observations) from all nine provinces to obtain per-capita sugar, calories, and volume from taxable and non-taxable beverages purchased before and after the HPL announcement and implementation. We describe survey-weighted means for each period, and regression-controlled predictions of outcomes and counterfactuals based on pre-HPL announcement trends, with bootstrapped 95% CIs, and stratify results by socioeconomic status.

FINDINGS

Mean sugar from taxable beverage purchases fell from 16·25 g/capita per day (95% CI 15·80-16·70) to 14·26 (13·85-14·67) from the pre-HPL announcement to post-announcement period, and then to 10·63 g/capita per day (10·22-11·04) in the year after implementation. Mean volumes of taxable beverage purchases fell from 518·99 mL/capita per day (506·90-531·08) to 492·16 (481·28-503·04) from pre-announcement to post announcement, and then to 443·39 mL/capita per day (430·10-456·56) after implementation. Across these time periods, there was a small increase in the purchases of non-taxable beverages, from 283·45 mL/capita per day (273·34-293·56) pre-announcement to 312·94 (296·29-329·29) post implementation. When compared with pre-announcement counterfactual trends, reductions in taxable beverage purchase outcomes were significantly larger than the unadjusted survey-weighted observed reductions. Households with lower socioeconomic status purchased larger amounts of taxable beverages in the pre-announcement period than did households with higher socioeconomic status, but demonstrated bigger reductions after the tax was implemented.

INTERPRETATION

The announcement and introduction of South Africa's HPL were followed by reductions in the sugar, calories, and volume of beverage purchases.

FUNDING

Bloomberg Philanthropies, International Development Research Centre, South African Medical Research Council, and the US National Institutes of Health.

Availability and advertising of sugar sweetened beverages in South African public primary schools following a voluntary pledge by a major beverage company: a mixed methods study

Background: Towards the end of the 2017 school year, a prominent beverage company in South Africa pledged to remove their sugar-sweetened beverages (SSBs) and advertisements from primary schools in order to contribute to the realization of a healthy school environment.Objectives: To assess the availability and advertising of the company's beverages in public primary schools in Gauteng province following their voluntary pledge to remove the products, and to explore perceptions of school staff regarding SSB availability in schools and processes related to the implementation of the pledge.Methods: In 2019, we conducted a representative survey of public sector primary (elementary) schools in Gauteng province, South Africa. A random sample of schools was drawn, with schools stratified by whether or not they charge fees. This was a proxy for the socioeconomic status of the locale and student body. At each school, the availability of beverages and presence of advertising or not was assessed by an observational audit tool and differences across fee status assessed by Pearson χ 2 test. Semi-structured interviews were conducted with a purposive sample of school officials. Data from the interviews were coded and thematic analysis conducted.Results: Two years following a voluntary pledge, the company's carbonated SSBs were available for sale in 54% (CI: 45-63%) of schools with tuck shops and advertised in 31% (CI: 25-39%). Qualitative interviews revealed a complex landscape of actors within schools, which, combined with indifference or resistance to the pledge, may have contributed to the continued availability of SSBs.Conclusions: Though we were unable to examine SSB availability before and after the pledge, our findings provide some preliminary evidence that voluntary pledges by commercial entities are not sufficient to remove SSBs and advertisements from schools. Mandatory regulations coupled with in-depth engagement with schools may be an avenue to pursue in the future.

The potential global gains in health and revenue from increased taxation of tobacco, alcohol and sugar-sweetened beverages: a modelling analysis

Introduction

Globally, a growing burden of morbidity and mortality is attributable to lifestyle behaviours, and in particular to the consumption of tobacco, alcohol and sugar-sweetened beverages (SSB). In low-income and middle-income countries, this increased disease burden falls on already encumbered and resource-constrained healthcare systems. Fiscal policies, specifically taxation, can lower consumption of tobacco, alcohol and SSB while raising government revenues.

Methods

We simulated the health and economic effects of taxing cigarettes, alcohol and SSB over 50 years for 30-79 years old populations using separate mathematical models for each commodity that incorporated country-level epidemiological, demographic and consumption data. Based on data availability, national-level health effects of higher tobacco, alcohol and SSB taxes were simulated in 141, 166 and 176 countries, respectively, which represented 92%, 97% and 95% of the global population, respectively. Economic effects for tobacco, alcohol and SSB were estimated for countries representing 91%, 43% and 83% of the global population, respectively. These estimates were extrapolated to the global level by matching countries according to income level.

Results

Over 50 years, taxes that raise the retail price of tobacco, alcoholic beverages and SSB by 20% could result in a global gain of 160.7 million (95% uncertainty interval (UI): 96.3 to 225.2 million), 227.4 million (UI: 161.2 to 293.6 million) and 24.3 million (UI: 15.7 to 35.4 million) additional life years, respectively.

Conclusion

Excise tax increases on tobacco, alcohol and SSB can produce substantial health gains by reducing premature mortality while raising government revenues, which could be used to increase public health funding.

The distributional impact of taxing sugar-sweetened beverages: findings from an extended cost-effectiveness analysis in South Africa

BACKGROUND

Facing increasing obesity prevalence and obesity-related disease burden, South Africa has devised an obesity prevention strategy that includes a recently implemented tax on the sugar content of sugar-sweetened beverages (SSB). We assess the potential distributional impact (across socioeconomic groups) of this tax on type 2 diabetes mellitus (T2DM) incidence and associated mortality and its financial burden on households.

METHODS

We conducted an extended cost-effectiveness analysis of the new 10% tax on SSBs in South Africa, and estimated: the averted premature deaths related to T2DM, the financial benefits to households (out-of-pocket (OOP) medical costs and indirect costs due to productivity losses averted), the increased government tax revenues and healthcare savings for the government, all across income quintiles.

FINDINGS

A 10% SSB tax increase would avert an estimated 8000 T2DM-related premature deaths over 20 years, with most deaths averted among the third and fourth income quintiles. The government would save about South African rand (ZAR) 2 billion (US$140 million) in subsidised healthcare over 20 years; and would raise ZAR6 billion (US$450 million) in tax revenues per annum. The bottom two quintiles would bear the smallest tax burden increase (36% of the additional taxes). The bottom two income quintiles would also have the lowest savings in OOP payments due to significant subsidisation provided by government healthcare. Lastly, an estimated 32 000 T2DM-related cases of catastrophic expenditures and 12 000 cases of poverty would be averted.

CONCLUSIONS

SSB taxation would have a substantial distributional impact on obesity-related premature deaths, cost savings to the government and the financial outcomes of South Africa's population.

The direct medical cost of type 2 diabetes mellitus in South Africa: a cost of illness study

Background: Type 2 diabetes mellitus (T2DM) is known to require continuous clinical care and management that consumes significant health-care resources. These costs are not well understood, particularly in low- and middle-income countries. Objective: The aim of this study was to estimate the direct medical costs associated with T2DM in the South African public health sector and to project an estimate of the future direct costs of T2DM by 2030. Methods: A cost of illness study was conducted to estimate the direct medical costs of T2DM in South Africa in 2018 and to make projections for potential costs in 2030. Costs were estimated for diagnosis and management of T2DM, and related complications. Analyses were implemented in Microsoft Excel, with sensitivity analysis conducted on particular parameters. Results: In 2018, public sector costs of diagnosed T2DM patients were approximately ZAR 2.7 bn and ZAR 21.8 bn if both diagnosed and undiagnosed patients are considered. In real terms, the 2030 cost of all T2DM cases is estimated to be ZAR 35.1 bn. Approximately 51% of these estimated costs for 2030 are attributable to the management of T2DM, and 49% are attributable to complications. Conclusion: T2DM imposes a significant financial burden on the public healthcare system in South Africa. Treatment of all prevalent cases would incur a cost equivalent to approximately 12% of the total national health budget in 2018. With rising prevalence, direct costs will grow if current care regimes are maintained and case-finding improved. Increased financial resources are necessary in order to deliver effective services to people with T2DM.

Simulating the impact of excise taxation for disease prevention in low-income and middle-income countries: an application to South Africa

Introduction

Excise taxes are policy tools that have been applied internationally with some success to reduce consumption of products adversely impacting population health including tobacco, alcohol and increasingly junk foods and sugary beverages. As in other low-income and middle-income countries, South Africa faces a growing burden of lifestyle diseases; accordingly we simulate the impact of multiple excise tax interventions in this setting.

Methods

We construct a mathematical model to simulate the health and revenue effects of increased excise taxes, which is adaptable to a variety of settings given its limited data requirements. Applying the model to South Africa, we simulate the impact of increased tax rates on tobacco and beer and of the introduction of a tax on sugar-sweetened beverages (SSB). Drawing on surveys of product usage and risk factor prevalence, the model uses a potential impact fraction to simulate the health effects of tax interventions.

Results

Adopting an excise rate of 60% on tobacco would result in a gain of 858 923 life-years (95% uncertainty interval (UI) 480 188 to 1 310 329), while adopting an excise rate of 25% on beer would result in a gain of 568 063 life-years (95% UI 412 110 to 775 560) and the adoption of a 20% tax on SSBs would result in a gain of 688 719 life-years (95% UI 321 788 to 1 079 653).

Conclusion

More aggressive excise tax policies on tobacco, beer and SSBs in South Africa could result in meaningful improvements in population health and raised revenue.

Sugary beverage taxation in South Africa: Household expenditure, demand system elasticities, and policy implications

South Africa faces a severe and growing obesity epidemic. Obesity and its co-morbidities raise public and private expenditures on healthcare. Sugary beverages are heavily consumed in South Africa and are linked to the onset of overweight and obesity. Excise taxation of sugary beverages has been proposed and adopted in other settings as a means to reduce harms from their consumption. A tax on the sugar content of non-alcoholic beverages has been proposed for implementation in South Africa, however, the public health effects and revenue raising potential of this measure hinges on estimates of the targeted beverages own- and cross-price elasticities. This study applies demand system methods by combining expenditure survey data and sub-national price data to provide the first estimates of price and expenditure elasticities for categories of soft drinks that would be subject to South Africa's proposed sugary beverage tax. The results suggest that demand for these products is sufficiently price-elastic such that a significant reduction in consumption may result from a tax.

Decomposing race and gender differences in underweight and obesity in South Africa

Using data from the National Income Dynamics Study, we document differentials in both underweight and obesity across race and gender in post-Apartheid South Africa. Using a nonlinear decomposition method, we decompose these differences across gender within race and then across race within gender. Less than one third of the differences in obesity and underweight across gender are explained by differences in covariates. In contrast, at least 70% of the obesity differences across race are explained by differences in covariates. Behavioral variables such as smoking and exercise explain the largest part of the bodyweight differentials across gender. For bodyweight differentials across race within gender, however, socioeconomic status and background variables have the largest explanatory power for obesity differentials, while background variables play the key role in explaining the underweight differentials. These results indicate that eradicating obesity and underweight differentials will require targeting policies to specific groups.

Lenses for learning: visual techniques in natural resource management

In this study, we explored the use of selected visual techniques (e.g. video, photography, diagramming) in facilitating learning among Indigenous communities living in remote protected areas at sites in Vietnam and Australia. The techniques were employed during interviews and workshops aimed at accessing and enhancing local peoples' perspectives on their landscape and on specific natural resource management issues. The effectiveness of the different techniques for enabling learning varied markedly with the context, highlighting the need for facilitator skill and flexibility in application of techniques. Visual techniques helped to engage participants; encourage unrestrained and lateral thinking; provide opportunities for self-expression and reflection; and to expose participants to perspectives of other community members. Valuable insights emerged on broad aspects of learning and these were incorporated into a simple model that highlights three types of conceptualisation found to be important in these processes.

The role of the maturation-inducing steroid, 17,20beta-dihydroxypregn-4-en-3-one, in male fishes: a review

The major progestin in teleosts is not progesterone, as in tetrapods, but 17,20beta-dihydroxypregn-4-en-3-one (17,20beta-P) or, in certain species, 17,20beta,21-trihydroxy-pregn-4-en-3-one (17,20beta,21-P). Several functions for 17,20beta-P and 17,20beta,21-P have been proposed (and in some cases proved). These include induction of oocyte final maturation and spermiation (milt production), enhancement of sperm motility (by alteration of the pH and fluidity of the seminal fluid) and acting as a pheromone in male cyprinids. Another important function, initiation of meiosis (the first step in both spermatogenesis and oogenesis), has only very recently been proposed. This is a process that takes place at puberty in all fishes and once a year in repeat spawners. The present review critically examines the evidence to support the proposed functions of 17,20beta-P in males, including listing of the evidence for the presence of 17,20beta-P in the blood plasma of male fishes and discussion of why, in many species, it appears to be absent (or present at low and, in some cases, unvarying concentrations); consideration of the evidence, obtained mainly from in vitro studies, for this steroid being predominantly produced by the testis, for its production being under the control of luteinizing hormone (gonadotrophin II) and, at least in salmonids, for two cell types (Leydig cells and sperm cells) being involved in its synthesis; discussion of the factors involved in the regulation of the switch from androgen to 17,20beta-P production that seems to occur in many species just at the time of spermiation; discussion of the effects of in vivo injection and application of 17,20beta-P (and closely related compounds) in males; a listing of previously published evidence that supports the proposed new function of 17,20beta-P as an initiator of meiosis; finally, discussion of the evidence for environmental endocrine disruption by progestins in fishes.

Milt production in goldfish: regulation by multiple social stimuli

Previous studies in goldfish (Carassius auratus) demonstrate that milt (sperm and seminal fluid) volume is increased both by a preovulatory steroidal pheromone, 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17,20 beta-P), that acts by increasing serum concentrations of gonadotropin II (GTH-II), and by a post-ovulatory prostaglandin (PG) pheromone, that acts by stimulating sexual interactions. Here, we show that male goldfish also increase milt volume when isolated for 24 h, or when placed with another male injected with human chorionic gonadotropin (hCG) for 12 h. In contrast to the milt increase induced by pheromonal 17,20 beta-P, the milt increase following isolation or exposure to hCG-injected males was not associated with increased serum GTH-II. Serum growth hormone also was unaffected, although serum testosterone increased in isolated males. The absence of GTH-II increase following isolation or exposure to hCG-injected males and the long latency time for these two types of responses, suggests these effects are mediated by a novel mechanism as yet undescribed. The present findings suggest that sperm competition has selected for complex mechanisms regulating milt production and fertility in goldfish: males regulate milt production not only in response to stimulatory pheromonal cues from ovulatory females, but also in response to unknown stimulatory and inhibitory cues from male competitors.

DcAGP1, a secreted arabinogalactan protein, is related to a family of basic proline-rich proteins

A cDNA corresponding to the core protein of an immunoaffinity-purified arabinogalactan protein (AGP) secreted aucus carota (carrot) cells in liquid culture was isolated. This cDNA, DcAGP1, encodes a new class of non-classical' AGP with strong similarity to a family of basic proline-rich proteins. The protein is rich in proline (17%), alanine (10%) and lysine (11%) and contains four distinct domains: a signal peptide, a proline-rich domain, a histidine-rich basic domain and a cysteine-containing 'PAC' domain that is found in a range of other cell wall proteins. The protein contains several sequence motifs found in otherwise unrelated cell wall proteins, but also displays some unique features. Northern blot analyses show that while the DcAGP1 transcript is abundant in the suspension-culture cells from which the AGP was obtained; in carrot seedlings the gene is only expressed at low levels in the roots and it is neither wound- nor stress-inducible. Furthermore, northern and western blot analyses demonstrate that the core polypeptide of DcAGP1 is differentially glycosylated in two different carrot suspension cultures. The unusual features of the protein sequence suggest that the DcAGP1 protein is a member of a family of basic proline-rich proteins defined by the C-terminal PAC domain, and the possible function(s) of the DcAGP1 protein is considered in the light of current views on AGP structure and function.

Inhibition of phenolic acid metabolism results in precocious cell death and altered cell morphology in leaves of transgenic tobacco plants

Several complex phenotypic changes are induced when the transcription factor AmMYB308 is overexpressed in transgenic tobacco plants. We have previously shown that the primary effect of this transcription factor is to inhibit phenolic acid metabolism. In the plants that we produced, two morphological features were prominent: abnormal leaf palisade development and induction of premature cell death in mature leaves. Evidence from the analysis of these transgenic plants suggests that both changes resulted from the lack of phenolic intermediates. These results emphasize the importance of phenolic secondary metabolites in the normal growth and development of tobacco. We suggest that phenolic acid derivatives are important signaling molecules in the final stages of leaf palisade formation and that phenolic acid derivatives also play a prominent role in tissue senescence.

Inhibition of phenolic acid metabolism results in precocious cell death and altered cell morphology in leaves of transgenic tobacco plants

Several complex phenotypic changes are induced when the transcription factor AmMYB308 is overexpressed in transgenic tobacco plants. We have previously shown that the primary effect of this transcription factor is to inhibit phenolic acid metabolism. In the plants that we produced, two morphological features were prominent: abnormal leaf palisade development and induction of premature cell death in mature leaves. Evidence from the analysis of these transgenic plants suggests that both changes resulted from the lack of phenolic intermediates. These results emphasize the importance of phenolic secondary metabolites in the normal growth and development of tobacco. We suggest that phenolic acid derivatives are important signaling molecules in the final stages of leaf palisade formation and that phenolic acid derivatives also play a prominent role in tissue senescence.

The steroid pheromone 4-pregnen-17,20ss-diol-3-one increases fertility and paternity in goldfish

Previous studies in goldfish (Carassius auratus) showed that the oocyte maturation-inducing steroid 4-pregnen-17,20ss-diol-3-one (17,20ssP) functions after release as a pheromone that increases male serum gonadotropin II (GtH II) concentration, milt (sperm and seminal fluid) volume and sexual activity, effects hypothesized to increase male reproductive success in the sperm competition of multi-male spawnings. The present study tested this hypothesis by determining whether overnight exposure to 17,20ssP increases fertility. In pair spawnings, 17,20ssP-exposed males fertilized a greater percentage of eggs than did control males, apparently because 17,20ssP-exposed males had more releasable sperm at the onset of spawning. Microsatellite DNA paternity analysis showed that 17,20ssP-exposed males also fertilized more eggs in competitive spawnings involving one control male and one 17,20ssP-exposed male. This effect of 17,20ssP on competitive fertility could be due to demonstrated increases in spawning activity, milt volume, duration of sperm motility and proportion of motile sperm. However, it appears that a change in sperm quality is a major component of the pheromonal effect because, in competitive in vitro fertilizations, sperm from 17,20ssP-exposed males fertilized more eggs than did sperm from control males. The results indicate that the response to pheromonal 17,20ssP is a major determinant of reproductive success in male goldfish.

Androgen induction of male sexual behaviors in female goldfish

The effectiveness of testosterone (T) and 11-ketotestosterone (K) in inducing male-typical sex behaviors in goldfish was examined by implanting intact adult females with one empty (blank) Silastic implant (B females), one implant containing T or K, or one T and one K implant (T + K females). Behavior of the four female groups was compared to that of untreated males and males containing a blank implant. Male-typical behaviors (coutship, spawning) and associated behavioral changes (increased activity, reduced spontaneous feeding) were assessed 3.5 and 4.5 months after implant in 30-min tests in which the test female or male was allowed to interact with a stimulus female in which sexual receptivity and attractivity had been induced by acute prostaglandin F2alpha injection. Prostaglandin-induced female-typical spawning behavior in the test females and males was also assessed 4.5 months after implant in a 60-min test for female-typical behavior in which the test fish was injected with prostaglandin and placed immediately with a sexually active male. Blood samples 5 months postimplant showed that implants generated physiological levels of T and K. In both tests for male-typical behaviors, K and T + K females exhibited the full suite of behaviors shown by spawning males, e.g., male-typical courtship and spawning, increased swimming activity, and reduced spontaneous feeding. Although behaviors of K and T + K females did not differ, those of T + K females were more often equivalent to those of males and significantly different from those of B females. T females exhibited marginal male-typical behaviors which never differed significantly from those of B females. Androgen-treated females exhibited female-typical; spawning behaviors equivalent to that of males and B females. The results show that adult female goldfish can be behaviorally masculinzed without behavioral defeminization, and suggest that male-typical sex behaviors in goldfish are dependent on K, although other steroids also may be required. The inducible behavioral bisexuality of goldfish, a gonochoristic species, is discussed in terms of the prevalence of hermaphroditism in teleosts.

Prostaglandin-induced female spawning behavior in goldfish (Carassius auratus) appears independent of ovarian influence

This study was conducted to determine whether prostaglandin f2 alpha (PGF)-induced spawning behavior in female goldfish (Carassius auratus) is influenced by sex steroids or by the stage of ovarian development (assessed by gonadosomatic index (GSI), ovary weight expressed as a percentage of body weight). In two groups of intact females with GSI values ranging from 0.2 to 16.6% (Experiment 1) and 0.6 to 12.7% (Experiment 5), respectively, there was a significant positive correlation between PGF-induced spawning behavior and GSI; however, within either the previtellogenic fish (GSI < 2.5%) or vitellogenic fish (GSI > 2.5%) of either experiment, the correlation between PGF-induced spawning and GSI was not significant. In one ovariectomy experiment, PGF-induced spawning behavior in ovariectomized fish remained equivalent to that of intact and sham fish between 3 and 13 weeks postsurgery. In a second ovariectomy experiment, ovariectomy did not decrease PGF-induced spawning of ovariectomized fish below presurgery levels, but did result in postsurgery spawning that was significantly less than that of intact and sham fish. At 4 weeks postovariectomy, PGF-induced spawning in females that had received blank silastic implants at surgery was no different from spawning of ovariectomized females implanted with either testosterone or 17 beta-estradiol. PGF-induced spawning also was unaffected by injection of the oocyte maturation-inducing steroid 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one 16 hr before PGF injection. Together the results indicate that factors associated with ovarian development have only minor influence at most on PGF-induced female spawning behavior, and support earlier proposals that female sex behaviors in externally fertilizing vertebrates are regulated not by ovarian steroids but by prostaglandins synthesized when ovulated oocytes are in the reproductive tract.

Antiestrogenic action of clomiphene citrate in goldfish

Hypophysectomized goldfish with regressed ovaries were injected with clomiphene citrate. No vitellogenesis was induced in the regressed ovaries. This indicates that clomiphene may be antiestrogenic in goldfish as far as induction of vitellogenesis is concerned.

Mode of action of clomiphene citrate in inducing ovulation of goldfish

Hypophysectomized and sham-operated gravid goldfish were injected with clomiphene citrate. Only the sham-operated fish ovulated. This indicates that clomiphene citrate acts through the hypophyseal axis.