Combined Effects of Early Life Stress and Prolonged Exposure to Western Diet on Emotional Responses and Gut Microbiota.

BACKGROUND: Exposure to early life stress (ELS) and maternal consumption of a high-fat and high-sugar diet can have detrimental effects on adult emotional responses. The microbiota and gut-brain axis have been proposed as playing a mediating role in the regulation of stress and emotion. METHOD: Young male rats were exposed to maternal separation (MS) together with maternal and postnatal consumption of a HFS diet (45%kcal saturated fat, 17%kcal sucrose). Anxiety-like behaviour was evaluated using an elevated zero-maze, and depression-like behaviour using the forced-swim and sucrose preference tests. Microbiota composition and derived metabolites were also analysed in faecal samples using a gas chromatograph and mass spectrometry. RESULTS: Combined exposure to MS and lifelong consumption of a HFS diet partially reversed the abnormal anxiety-like and depression-like behaviours in early adulthood caused by each adverse factor alone. Diet composition had a greater negative impact than ELS exposure on the gut microbiota, and both environmental factors interacted with microbiota composition partially counteracting their negative effects. CONCLUSIONS: The effects of exposure to early life stress and a HFS diet independently are partially reversed after the combination of both factors. These results suggest that ELS and diet interact to modulate adult stress response and gut microbiota.

A shift to a standard diet after exposure to a high-fat, high-sucrose diet from gestation to weaning restores brain metabolism and behavioral flexibility in adult rats.

Prolonged consumption of diets high in saturated fat and sugar has been related to obesity and overweight, which in turn are linked to cognitive impairment in both humans and rodents. This has become a current issue, especially in children and adolescents, because these stages are crucial to neurodevelopmental processes and programming of adult behavior. To evaluate the effects of gestational and early exposure to an obesogenic diet, three groups with different dietary patterns were established: high-fat and high-sucrose diet (HFS), standard diet (SD), and a dietary shift from a high-fat, high-sucrose diet to a standard diet after weaning (R). Spatial learning and behavioral flexibility in adult male and female Wistar rats were evaluated using the Morris water maze (MWM) at PND 60. Furthermore, regional brain oxidative metabolism was assessed in the prefrontal cortex and the hippocampus. Contrary to our hypothesis, the HFS diet groups showed similar performance on the spatial learning task as the other groups, although they showed impaired cognitive flexibility. The HFS group had increased brain metabolic capacity compared to that of animals fed the standard diet. Shifting from the HFS diet to the SD diet after weaning restored the brain metabolic capacity in both sexes to levels similar to those observed in animals fed the SD diet. In addition, animals in the R group performed similarly to those fed the SD diet in the Morris water maze in both tasks. However, dietary shift from HFS diet to standard diet after weaning had only moderate sex-dependent effects on body weight and fat distribution. In conclusion, switching from an HFS diet to a balanced diet after weaning would have beneficial effects on behavioral flexibility and brain metabolism, without significant sex differences.

Combined Effects of Early Life Stress and Prolonged Exposure to Western Diet on Emotional Responses and Gut Microbiota / Efectos Combinados del Estrés Vital Temprano y la Exposición Prolongada a la Dieta Occidental Sobre las Respuestas Emocionales y la Microbiota Intestinal

Background: Exposure to early life stress (ELS) and maternal consumption of a high-fat and high-sugar diet can have detrimental effects on adult emotional responses. The microbiota and gut-brain axis have been proposed as playing a mediating role in the regulation of stress and emotion. Method: Young male rats were exposed to maternal separation (MS) together with maternal and postnatal consumption of a HFS diet (45%kcal saturated fat, 17%kcal sucrose). Anxiety-like behaviour was evaluated using an elevated zero-maze, and depression-like behaviour using the forced-swim and sucrose preference tests. Microbiota composition and derived metabolites were also analysed in faecal samples using a gas chromatograph and mass spectrometry. Results: Combined exposure to MS and lifelong consumption of a HFS diet partially reversed the abnormal anxiety-like and depression-like behaviours in early adulthood caused by each adverse factor alone. Diet composition had a greater negative impact than ELS exposure on the gut microbiota, and both environmental factors interacted with microbiota composition partially counteracting their negative effects. Conclusions: The effects of exposure to early life stress and a HFS diet independently are partially reversed after the combination of both factors. These results suggest that ELS and diet interact to modulate adult stress response and gut microbiota.(AU)

Antecedentes: El estrés temprano (ET) y el consumo materno de una dieta alta en grasas y azúcares (HFS) pueden tener efectos perjudiciales sobre las respuestas emocionales en la adultez. La microbiota y el eje intestino-cerebro podrían mediar la regulación del estrés y las emociones. Método: Ratas macho jóvenes se expusieron a separación materna (SM) y a consumo materno y postnatal de una dieta HFS (45%kcal grasa saturada, 17%kcal sacarosa). Se evaluó el comportamiento ansioso mediante el laberinto cero elevado y el comportamiento depresivo mediante natación forzada y preferencia por sacarosa. Se analizó la microbiota en heces empleando cromatografía de gas y espectrometría de masas. Resultados: La exposición combinada a la SM y el consumo de una dieta HFS revirtió parcialmente la ansiedad y depresión en adultos causadas independientemente por cada factor adverso. La dieta influyó negativamente más que la exposición a ET en la microbiota y ambos factores modificaron su composición contrarrestando parcialmente sus efectos negativos. Conclusiones: Los efectos del ET y una dieta HFS por independiente varían con respecto a los efectos de la combinación de ambos factores, sugiriendo que el ET y la dieta interactúan modulando en el adulto la respuesta al estrés y la microbiota intestinal.(AU)

Rumen Microbial Predictors for Short-Chain Fatty Acid Levels and the Grass-Fed Regimen in Angus Cattle.

The health benefits of grass-fed beef are well documented. However, the rumen microbiome features in beef steers raised in a grass-fed regimen have yet to be identified. This study examined the rumen microbiome profile in the feeding regimes. Our findings show that the rumen microbiome of the grass-fed cattle demonstrated greater species diversity and harbored significantly higher microbial alpha diversity, including multiple species richness and evenness indices, than the grain-fed cattle. Global network analysis unveiled that grass-fed cattle's rumen microbial interaction networks had higher modularity, suggesting a more resilient and stable microbial community under this feeding regimen. Using the analysis of compositions of microbiomes with a bias correction (ANCOM-BC) algorithm, the abundance of multiple unclassified genera, such as those belonging to Planctomycetes, LD1-PB3, SR1, Lachnospira, and Sutterella, were significantly enriched in the rumen of grass-fed steers. Sutterella was also the critical genus able to distinguish the two feeding regimens by Random Forest. A rumen microbial predictor consisting of an unclassified genus in the candidate division SR1 (numerator) and an unclassified genus in the order Bacteroidales (denominator) accurately distinguished the two feeding schemes. Multiple microbial signatures or balances strongly correlated with various levels of SCFA in the rumen. For example, a balance represented by the log abundance ratio of Sutterella to Desulfovibrio was strongly associated with acetate-to-propionate proportions in the rumen (R2 = 0.87), which could be developed as a valuable biomarker for optimizing milk fat yield and cattle growth. Therefore, our findings provided novel insights into microbial interactions in the rumen under different feed schemes and their ecophysiological implications. These findings will help to develop rumen manipulation strategies to improve feed conversion ratios and average daily weight gains for grass- or pasture-fed cattle production.

Sexual dimorphism in spatial learning and brain metabolism after exposure to a western diet and early life stress in rats.

Prolonged daily intake of Western-type diet rich in saturated fats and sugars, and exposure to early life stress have been independently linked to impaired neurodevelopment and behaviour in animal models. However, sex-specific effects of both environmental factors combined on spatial learning and memory, behavioural flexibility, and brain oxidative capacity have still not been addressed. The current study aimed to evaluate the impact of maternal and postnatal exposure to a high-fat and high-sugar diet (HFS), and exposure to early life stress by maternal separation in adult male and female Wistar rats. For this purpose, spatial learning and memory and behavioural flexibility were evaluated in the Morris water maze, and regional brain oxidative capacity and oxidative stress levels were measured in the hippocampus and medial prefrontal cortex. Spatial memory, regional brain oxidative metabolism, and levels of oxidative stress differed between females and males, suggesting sexual dimorphism in the effects of a HFS diet and early life stress. Males fed the HFS diet performed better than all other experimental groups independently of early life stress exposure. However, behavioural flexibility evaluated in the spatial reversal leaning task was impaired in males fed the HFS diet. In addition, exposure to maternal separation or the HFS diet increased the metabolic capacity of the prefrontal cortex and dorsal hippocampus in males and females. Levels of oxidative stress measured in the latter brain regions were also increased in groups fed the HFS diet, but maternal separation seemed to dampen regional brain oxidative stress levels. Therefore, these results suggest a compensatory effect resulting from the interaction between prolonged exposure to a HFS diet and early life stress.

Whole-Genome Assessment of Clinical Acinetobacter baumannii Isolates Uncovers Potentially Novel Factors Influencing Carbapenem Resistance.

Carbapenems-one of the important last-line antibiotics for the treatment of gram-negative infections-are becoming ineffective for treating Acinetobacter baumannii infections. Studies have identified multiple genes (and mechanisms) responsible for carbapenem resistance. In some A. baumannii strains, the presence/absence of putative resistance genes is not consistent with their resistance phenotype-indicating the genomic factors underlying carbapenem resistance in A. baumannii are not fully understood. Here, we describe a large-scale whole-genome genotype-phenotype association study with 349 A. baumannii isolates that extends beyond the presence/absence of individual antimicrobial resistance genes and includes the genomic positions and pairwise interactions of genes. Ten known resistance genes exhibited statistically significant associations with resistance to imipenem, a type of carbapenem: blaOXA-23, qacEdelta1, sul1, mphE, msrE, ant(3")-II, aacC1, yafP, aphA6, and xerD. A review of the strains without any of these 10 genes uncovered a clade of isolates with diverse imipenem resistance phenotypes. Finer resolution evaluation of this clade revealed the presence of a 38.6 kbp conserved chromosomal region found exclusively in imipenem-susceptible isolates. This region appears to host several HTH-type DNA binding transcriptional regulators and transporter genes. Imipenem-susceptible isolates from this clade also carried two mutually exclusive plasmids that contain genes previously known to be specific to imipenem-susceptible isolates. Our analysis demonstrates the utility of using whole genomes for genotype-phenotype correlations in the context of antibiotic resistance and provides several new hypotheses for future research.

Efecto de la sustitución de grasas en salchichas de tilapia roja (Oreochromis sp.) por una mezcla de piel de cerdo y fibra de quinua / Effect of fat replacement in red tilapia sausages (Oreochromis sp.) with a mixture of pork skin and quinoa fiber

RESUMEN La disminución del consumo de grasas saturadas aportadas por los alimentos de origen animal y la búsqueda de alimentos más sanos es una tendencia, a nivel mundial. La producción de tilapia en Colombia ha venido en franco crecimiento en las últimas décadas, lo cual, plantea la necesidad de búsqueda de alternativas para su procesamiento. Se evaluó la sustitución de grasas por una mezcla de piel de cerdo, agua y fibra de quinua (PCFQ) en salchichas de filete de tilapia. Se determinó la composición química de las salchichas elaboradas, el contenido calórico, el pH, las coordenadas de color CIELab, las pérdidas de humedad por cocción, la estabilidad de la emulsión, el perfil de textura y se estableció la apreciación sensorial. La adición de PCFQ conllevó a un aumento en la humedad y en las proteínas totales, gracias a la capacidad de retención de agua de la fibra de quinua. La salchicha con mayor adición de PCFQ (20%) obtuvo un 48,2% menos de grasas, un 32,3% menos de calorías y un 31,1% de pérdida de humedad por cocción, con relación a la salchicha control. Se obtuvieron emulsiones cárnicas más estables, con buenos parámetros de perfil de textura - TPA. Con relación a los parámetros sensoriales, no se apreciaron diferencias significativas entre las salchichas elaboradas y la salchicha control. Por lo anterior, se concluye que, la mezcla, se puede usar como sustituto de grasas en la elaboración de salchichas de filete de tilapia, sin afectar sus propiedades fisicoquímicas y sensoriales.

ABSTRACT The decrease in the consumption of saturated fats provided by animal foods and the search for healthier foods is a worldwide trend. Tilapia production in Colombia has been growing rapidly in recent decades, which raises the need to find alternatives for processing. The substitution of fats for a mixture of pork skin, water and quinoa fiber (PCFQ) in tilapia fillet sausages was evaluated. The chemical composition of the processed sausages, the caloric content, the pH, the CIELab color coordinates, the cooking moisture losses, the emulsion stability, the texture profile and the sensory assessment were determined. The addition of PCFQ led to an increase in moisture and total proteins, thanks to the water retention capacity of quinoa fiber. The sausage with the highest PCFQ addition (20%), obtained 48.2% less fat, 32.3% less calories and 31.1% loss of moisture from cooking compared to the control sausage. More stable meat emulsions were obtained with good texture profile parameters -TPA. Regarding sensory parameters, no significant differences were observed between processed sausages and control sausage. Therefore, it is concluded that the mixture can be used as a fat substitute in the preparation of tilapia fillet sausages, without affecting its physicochemical and sensory properties.

Current State of and Future Opportunities for Prediction in Microbiome Research: Report from the Mid-Atlantic Microbiome Meet-up in Baltimore on 9 January 2019.

Accurate predictions across multiple fields of microbiome research have far-reaching benefits to society, but there are few widely accepted quantitative tools to make accurate predictions about microbial communities and their functions. More discussion is needed about the current state of microbiome analysis and the tools required to overcome the hurdles preventing development and implementation of predictive analyses. We summarize the ideas generated by participants of the Mid-Atlantic Microbiome Meet-up in January 2019. While it was clear from the presentations that most fields have advanced beyond simple associative and descriptive analyses, most fields lack essential elements needed for the development and application of accurate microbiome predictions. Participants stressed the need for standardization, reproducibility, and accessibility of quantitative tools as key to advancing predictions in microbiome analysis. We highlight hurdles that participants identified and propose directions for future efforts that will advance the use of prediction in microbiome research.

Complete Genome Sequences of 14 Salmonella enterica Serovar Enteritidis Strains Recovered from Human Clinical Cases between 1949 and 1995 in the United States.

Salmonella enterica serovar Enteritidis is one of the most commonly isolated foodborne pathogens and is transmitted primarily to humans through consumption of contaminated poultry and poultry products. We are reporting completely closed genome and plasmid sequences of historical S Enteritidis isolates recovered from humans between 1949 and 1995 in the United States.

Bacterial genome adaptation to niches: divergence of the potential virulence genes in three Burkholderia species of different survival strategies.

BACKGROUND: Two closely related species Burkholderia mallei (Bm) and Burkholderia pseudomallei (Bp) are serious human health hazards and are potential bio-warfare agents, whereas another closely related species Burkholderia thailandensis (Bt) is a non-pathogenic saprophyte. To investigate the genomic factors resulting in such a dramatic difference, we first identified the Bm genes responsive to the mouse environment, and then examined the divergence of these genes in Bp and Bt. RESULTS: The genes down-expressed, which largely encode cell growth-related proteins, are conserved well in all three species, whereas those up-expressed, which include potential virulence genes, are less well conserved or absent notably in Bt. However, a substantial number of up-expressed genes is still conserved in Bt. Bm and Bp further diverged from each other in a small number of genes resulting from unit number changes in simple sequence repeats (ssr) in the homologs. CONCLUSION: Our data suggest that divergent evolution of a small set of genes, rather than acquisition or loss of pathogenic islands, is associated with the development of different life styles in these bacteria of similar genomic contents. Further divergence between Bm and Bp mediated by ssr changes may reflect different adaptive processes of Bm and Bp fine-tuning into their host environments.

Structural flexibility in the Burkholderia mallei genome.

The complete genome sequence of Burkholderia mallei ATCC 23344 provides insight into this highly infectious bacterium's pathogenicity and evolutionary history. B. mallei, the etiologic agent of glanders, has come under renewed scientific investigation as a result of recent concerns about its past and potential future use as a biological weapon. Genome analysis identified a number of putative virulence factors whose function was supported by comparative genome hybridization and expression profiling of the bacterium in hamster liver in vivo. The genome contains numerous insertion sequence elements that have mediated extensive deletions and rearrangements of the genome relative to Burkholderia pseudomallei. The genome also contains a vast number (>12,000) of simple sequence repeats. Variation in simple sequence repeats in key genes can provide a mechanism for generating antigenic variation that may account for the mammalian host's inability to mount a durable adaptive immune response to a B. mallei infection.