Larval Development in Tropical Gar (Atractosteus tropicus) Is Dependent on the Embryonic Thermal Regime: Ecological Implications under a Climate Change Context

In ectotherm species, environmental temperature plays a key role in development, growth, and survival. Thus, determining how temperature affects fish populations is of utmost importance to accurately predict the risk of climate change over fisheries and aquaculture, critical to warrant nutrition and food security in the coming years. Here, the potential effects of abnormal thermal regimes (24, 28 and 32 °C; TR24, TR28, and TR32, respectively) exclusively applied during embryogenesis in tropical gar (Atractosteus tropicus) has been explored to decipher the potential consequences on hatching and growth from fertilization to 16 days post-fertilization (dpf), while effects on skeletal development and body morphology were explored at fertilization and 16 dpf. Egg incubation at higher temperatures induced an early hatching and mouth opening. A higher hatching rate was obtained in eggs incubated at 28 °C when compared to those at 24 °C. No differences were found in fish survival at 16 dpf, with values ranging from 84.89 to 88.86%, but increased wet body weight and standard length were found in larvae from TR24 and TR32 groups. Thermal regime during embryogenesis also altered the rate at which the skeletal development occurs. Larvae from the TR32 group showed an advanced skeletal development, with a higher development of cartilaginous structures at hatching but reduced at 16 dpf when compared with the TR24 and TR28 groups. Furthermore, this advanced skeletal development seemed to determine the fish body morphology. Based on biometric measures, a principal component analysis showed how along development, larvae from each thermal regime were clustered together, but with each population remaining clearly separated from each other. The current study shows how changes in temperature may induce craniofacial and morphological alterations in fish during early stages and contribute to understanding the possible effects of global warming in early development of fish and its ecological implications.

Long segment “Hanging-snout” end ileosotmy a safe “Surgical disaster mitigating” technique for an “Un-brookeable” end ileum: a study of 23 cases over 12 years

Background: In 1952, Professor Bryan Brooke described his technique for everting an ileostomy in order to minimise skin excoriation1. Pouting, mucosa-everting Brooke’s ileostomy have been accepted as the best technique for stoma formation in almost all cases, save a few difficult situations – such as edematous friable bowel with bulky short mesentry! In such cases formation of standard Brooke’s ‘Pouting’ ileostomy is not only difficult, but an impossible and a dangerous surgical exercise! In these situations where the bowel is “Un-Brookeable” due to aforementioned causes. Over a period of 12 years we could device a formula – “Ray’s Criteria” to decide at operation, if a given ileum in a particular patient, is safely “Brookeable” (i.e. evertable into a neat Brooke, spouting ileostomy) or is “Un-Brookeable”.Methods: 23 patients were included in this study over 12 years, who due to the peculiarity of their body morphology (obesity or thick abdominal fat), edematous friable bowel with bulky mesentry, the ileum could not be drawn outside the abdomen and everted as Brooke’s ileostomy. The “Brookeability” of the exteriorized ileum was decided based on satisfying two issues of Ray’s criteria.Results: By using “Ray’s criteria”, we could seggregate patients safely as “Brookeable” and “Un-Brookeable”. Those deemed “Un-Brookable” underwent “Long segment Hanging snout” end ileostomy, which is the theme of our study.Conclusions: We are emphatic in stating that by using “Ray’s criteria” we could accurately segregate cases into “Brookeable” and “Un-Brookeable” ileum.

Composite trait Mendelian randomization reveals distinct metabolic and lifestyle consequences of differences in body shape

Obesity is a major risk factor for a wide range of cardiometabolic diseases, however the impact of specific aspects of body morphology remains poorly understood. We combined the GWAS summary statistics of fourteen anthropometric traits from UK Biobank through principal component analysis to reveal four major independent axes: body size, adiposity, predisposition to abdominal fat deposition, and lean mass. Mendelian randomization analysis showed that although body size and adiposity both contribute to the consequences of BMI, many of their effects are distinct, such as body size increasing the risk of cardiac arrhythmia (b = 0.06, p = 4.2 ∗ 10−17) while adiposity instead increased that of ischemic heart disease (b = 0.079, p = 8.2 ∗ 10−21). The body mass-neutral component predisposing to abdominal fat deposition, likely reflecting a shift from subcutaneous to visceral fat, exhibited health effects that were weaker but specifically linked to lipotoxicity, such as ischemic heart disease (b = 0.067, p = 9.4 ∗ 10−14) and diabetes (b = 0.082, p = 5.9 ∗ 10−19). Combining their independent predicted effects significantly improved the prediction of obesity-related diseases (p < 10−10). The presented decomposition approach sheds light on the biological mechanisms underlying the heterogeneity of body morphology and its consequences on health and lifestyle.

Building behavior does not drive rates of phenotypic evolution in spiders

Do animals set the course for the evolution of their lineage when manipulating their environment? This heavily disputed question is empirically unexplored but critical to interpret phenotypic diversity. Here, we tested whether the macroevolutionary rates of body morphology correlate with the use of built artifacts in a megadiverse clade comprising builders and nonbuilders—spiders. By separating the inferred building-dependent rates from background effects, we found that variation in the evolution of morphology is poorly explained by artifact use. Thus natural selection acting directly on body morphology rather than indirectly via construction behavior is the dominant driver of phenotypic diversity.