The impact of wildfires on the diet of <i>Podarcis lusitanicus</i> revealed by DNA metabarcoding

by Catarina Simões, Diana S. Vasconcelos, Raquel Xavier, Xavier Santos, Catarina Rato, D. James Harris

Fire has long been recognized as an important ecological and evolutionary force in plant communities, but its influence on vertebrate community ecology, particularly regarding predator-prey interactions, remains understudied. This study reveals the impact of wildfires on the diet of Podarcis lusitanicus, a lizard species inhabiting a fire-prone region in the Iberian Peninsula. In order to explore diet variability associated with different local burn histories, we evaluated P. lusitanicus diet across three types of sites in Northern Portugal: those had not burned since 2016, those burned in 2016, and those more recently burned in 2022. Podarcis lusitanicus is a generalist arthropod predator with dietary flexibility. Given the turnover of arthropod species after fire, it is expected to find variations in diet caused by different fire histories, especially between unburned and recently burned sites. From DNA metabarcoding of faecal samples, our study revealed that while prey richness remained unaffected by wildfire regime, significant shifts occurred in diet composition between more recently burned and unburned areas. Specifically, we found that differences in diet composition between these two fire regimes were due to the presence of Tapinoma ants and jumping spiders (Salticus scenicus). These prey were present in the diets of lizards occupying unburned areas, while these were absent in areas burned in 2022. Interestingly, diets in unburned areas and areas burned in 2016 showed no significant differences, highlighting the lizards’ ecological flexibility and the habitat’s resilience over time. The ant species T. topitotum was found in dominance in both burned areas, suggesting that this species may be fire tolerant. In addition, families such as Cicadellidae and Noctuidae were found to be more associated with more recently burned areas. The use of DNA metabarcoding in this study was essential to provide a more detailed and accurate view of predator-prey interactions in ecosystems susceptible to fire, and therefore a better understanding of changes in prey consumption in this fire-adapted ecosystem.

Prevalence and factors influencing drug-resistant tuberculosis in four regions of Ghana

by Esther Ba-Iredire, James Atampiiga Avoka, Luke Abanga, Abigail Awaitey Darkie, Emmanuel Junior Attombo, Eric Agboli

Introduction

The alarming rate of drug-resistant tuberculosis (DR-TB) globally is a threat to treatment success among positive tuberculosis (TB) cases. Studies aimed at determining the prevalence, trend of DR-TB and socio-demographic and clinical risk factors contributing to DR-TB in the four regions of Ghana are currently unknown. This study sought to determine the prevalence and trend of DR-TB, identify socio-demographic and clinical risk factors that influence DR-TB, and analyse the relationship between underweight and adverse drug reactions and treatment outcomes among DR-TB patients in four regions of Ghana.

Method

It was a retrospective review conducted over 5 years, from January 2018 to the end of December 2022. The data were retrieved from the DR-TB registers and folders at the Directly Observed Treatment (DOT) centres in the four regions. Analysis of the data was conducted using STATA version 17.

Results

The prevalence of DR-TB in Ashanti was 10.1%, Eastern 5.3%, 27.8% in Central, and 2.7% in the Upper West region for the year 2022. The overall prevalence rate of DR-TB for the period 2018–2022 was 13.8%. The socio-demographic and clinical risk factors that influence DR-TB in the four regions are: age, marital status (aOR 3.58, P-value Conclusion

The study shows that the prevalence of DR-TB in Ghana is low, probably not because the cases have reduced but due to inadequate GeneXpert machines to detect the cases. Age, marital status, education, alcohol intake, previously treated TB cases, adverse drug reactions, underweight, and treatment outcome are factors influencing the development of DR-TB. Therefore, interventions aimed at improving the nutritional status of DR-TB cases and minimising adverse drug reactions will improve treatment outcomes.

Physiological consequences of Aldolase C deficiency during lactation

by James A. Votava, Jing Fan, Brian W. Parks

The lactating mammary gland strongly induces de novo lipogenesis (DNL) to support the synthesis of fatty acids, triglycerides, and cholesterol found within milk. In monogastric species, glucose is a major substrate utilized for DNL within the lactating mammary gland and must be efficiently taken up and processed to supply cytosolic acetyl-CoA for DNL. Along with the enzymes of the DNL pathway, the glycolytic enzyme, Aldolase C (Aldoc), is transcriptionally upregulated and is highly expressed during lactation in the mammary gland, suggesting a role for Aldoc in lactation. Aldoc is also a transcriptional target of the sterol regulatory element binding proteins 1 and 2 (Srebp1 and Srebp2), which transcriptionally regulate enzymes within the DNL pathway and has recently been shown to regulate plasma cholesterol and triglycerides. Here, we investigate the role of Aldoc in lactation, by utilizing a whole-body Aldoc knockout mouse. Our results demonstrate that Aldoc has a significant impact on lactation, whereby pups nursing from Aldoc^-/- dams have reduced body weight. Biochemical analysis of milk identified that milk from Aldoc^-/- dams have significantly higher galactose, lower lactose, and cholesterol content. Mass spectrometry analysis of milk lipids from Aldoc^-/- dams revealed significantly lower quantities of medium and long chain fatty acid containing triglycerides, which has direct implications on lactation as these are the predominant triglycerides synthesized from glucose in human mammary gland. Overall, our results provide functional evidence for the contribution of Aldoc in mammary gland lactose and lipid synthesis during lactation.