Spatial Ecology and Resource Selection of Eastern Box Turtles

Eastern box turtles (Terrapene carolina carolina) are widely distributed throughout the eastern United States. Although once common throughout much of its distribution, the species has experienced declines in local populations. Understanding resource selection is important for the conservation of this species; however, few data exist on resource selection for eastern box turtles in the southeastern United States. We estimated home range and resource selection for 100 individual turtles in the Blue Ridge, Ridge and Valley, and Cumberland Plateau and Mountains physiographic regions in Tennessee, USA, from 2016 to 2018. We used step-selection functions to investigate eastern box turtle resource selection during May–August 2017 and May–August 2018 at 2 spatial scales. We classified vegetation type, measured vegetation composition and structure, recorded time since fire, and measured coarse woody debris abundance at 1,225 used telemetry locations and 1,225 associated available points. Home range sizes averaged 9.3 ha ± 3.0 (SE) using minimum convex polygon analysis, 8.25 ha ± 2.88 using 95% kernel density analysis, and 1.50 ha ± 0.56 using 50% kernel density analysis. Box turtles selected areas with greater visual obstruction at the 0–0.25-m level, greater amounts of 10-hour and 100-hour fuels (timelag categories used in fire-danger ratings), and greater litter depths compared to available locations. Box turtles were more likely to select areas with greater cover of brambles and coarser woody debris and were less likely to select areas with less vegetation cover. Vegetation type and time since last fire did not affect selection. Our data suggest that management activities that encourage greater understory vegetation cover, greater visual obstruction at the 0–0.25-m level, and greater bramble cover will enhance habitat quality for eastern box turtles. © 2020 The Wildlife Society.     

Ontogenic study of the brachiopod Dicoelosia by geometric morphometrics and morphing techniques

The distinctive brachiopod Dicoelosia King 1850 is characterized by a strongly bilobed outline. To date, studies have concentrated on its functional morphology, taxonomy and evolution; little attention has been paid to its ontogeny. Here, we map population variation by principal component analysis for over 80 specimens distributed across five species of Dicoelosia. Using geometric morphometrics with landmarks for some 40 specimens, the ontogenic trends in D. sp. nov. are compared with those of Dicoelosia biloba. In addition, the ontogenic pathway in D. sp. nov. is investigated by morphing with control points, a new technique introduced here to palaeontology. Combining the results above, the ontogeny of the key character of the genus, emargination, is modelled. Within single populations, taxa may develop from broad weakly emarginate forms into those that are elongate and deeply emarginate. As the identification of the genus and its species depends on external morphological characters, the definition of ontogenetic trends in each species is essential for taxonomic discrimination. Substantial population variation exists in many of its species; however, the morphing technique provides a method of simulation, predicting the full range of ontogenetic variation in given populations.     

Common Variation Neighbouring Micro-RNA 22 Is Associated with Increased Left Ventricular Mass

Aims

Previous genome-wide linkage analysis has suggested that chromosomal region 17p13.3 may harbour genes influencing left ventricular mass (LVM) in man. To date, the genetic factors accounting for LVM variability remain largely unknown but a non-coding RNA gene within this region, micro-RNA 22 (miR-22), has been implicated in cardiac hypertrophy and heart failure in animal models. We thus investigated the relationship between common genetic polymorphisms surrounding miR-22 and left ventricular mass in a family-based association study.

Methods and Results

We studied a cohort of 255 families comprising 1,425 individuals ascertained via a hypertensive proband. Ten single nucleotide polymorphisms which together tagged common genetic variation surrounding the miR-22 gene were genotyped. There was evidence of association between the rs7223247 polymorphism, which lies within the 3′UTR of a gene of unknown function, TLCD2, immediately downstream from miR-22, and left ventricular mass determined by Sokolow-Lyon voltage (Bonferroni corrected p-value = 0.038). The T allele at rs7223247 was associated with an 0.272 standard deviation higher Sokolow-Lyon voltage. Genotype was responsible for ∼1% of the population variability in LVM.

Conclusions

Genotype at the rs7223247 polymorphism affects left ventricular mass determined by Sokolow-Lyon voltage. The neighbouring genes miR-22 and TLCD2 are strong candidates to account for this observation.     

Spatial pattern of invasive and native graminoids in the Brazilian cerrado

Plant Ecology - Invasive grasses are an important threat in tropical savannas and grasslands and may be affected by natural and anthropogenic features of the environment. They may affect native...     

Peroxisome proliferator-activated receptor gamma 2 and acyl-CoA synthetase 5 polymorphisms influence diet response

Peroxisome proliferator-activated receptor gamma (PPARgamma) and its response gene, Acyl CoA synthetase 5 (ACSL5), which has an important role in fatty acid metabolism, may affect weight loss in response to caloric restriction. Therefore, we aimed to determine whether these genes were involved in the interindividual response to dietary treatment. Genotypic/phenotypic comparisons were made between selected obese women from the quintiles losing the most (diet responsive, n = 74) and the quintiles losing the least (diet-resistant, n = 67) weight in the first 6 weeks of a 900-kcal formula diet. Two common PPARgamma single nucleotide polymorphisms, Pro(12)Ala and C1431T, and eight polymorphisms across the ACSL5 gene were selected for single locus and haplotypic association analyses. The PPARgamma Pro(12)Ala single nucleotide polymorphism was associated with diet resistance (odds ratio = 3.48, 95% confidence interval = 1.41 to 8.56, p = 0.03), and the rs2419621, located in the 5'untranslated region of the ACSL5 gene, displayed the strongest association with diet response (odds ratio = 3.45, 95% confidence interval = 1.61 to 7.69, p = 0.001). Skeletal muscle ACSL5 mRNA expression was significantly lower in carriers of the wildtype compared with the variant rs2419621 allele (p = 0.03). Our results suggest a link between PPARgamma2 and ACSL5 genotype and diet responsiveness.     

Global distribution of cryptic native,introduced and hybrid lineages in the widespread estuarine amphipod Ampithoe valida

Biological invasions can pose a severe threat to coastal ecosystems, but are difficult to track due to inaccurate species identifications and cryptic diversity. Here, we clarified the cryptic diversity and introduction history of the marine amphipod Ampithoe valida by sequencing a mtDNA locus from 683 individuals and genotyping 10,295 single-nucleotide polymorphisms (SNPs) for 349 individuals from Japan, North America and Argentina. The species complex consists of three cryptic lineages: two native Pacific and one native Atlantic mitochondrial lineage. It is likely that the complex originated in the North Pacific and dispersed to the north Atlantic via a trans-arctic exchange approximately 3 MYA. Non-native A. valida in Argentina have both Atlantic mitochondrial and nuclear genotypes, strongly indicating an introduction from eastern North America. In two eastern Pacific estuaries, San Francisco Bay and Humboldt Bay, California, genetic data indicate human-mediated hybridization of Atlantic and Pacific sources, and possible adaptive introgression of mitochondrial loci, nuclear loci, or both. The San Francisco Bay hybrid population periodically undergoes population outbreaks and profoundly damages eelgrass Zostera marina thalli via direct consumption, and these ecological impacts have not been documented elsewhere. We speculate that novel combinations of Atlantic and Pacific lineages could play a role in A. valida’s unique ecology in San Francisco Bay. Our results reinforce the notion that we can over-estimate the number of non-native invasions when there is cryptic native structure. Moreover, inference of demographic and evolutionary history from mitochondrial loci may be misleading without simultaneous survey of the nuclear genome.

     

Comparison of the subcellular distribution of G-proteins in hepatocytes in situ and in primary cultures

The subcellular localization of the heterotrimeric G-proteins in hepatocytes in situ was compared to that in hepatocytes in primary culture. The ability of various ligands to activate adenylyl cyclase (AC) in membrane preparations was also investigated. In hepatocytes in situ the G proteins were mainly localized at the plasma membrane while in hepatocytes in culture they were predominantly cytoplasmic. The localization of the G-proteins in hepatocytes in situ correlates with their role in signal transduction. In homogenates prepared from the cultured cells, ligands which stimulate AC via G_sα were without effect, which was consistent with the localization of G_sα in the cytoplasmic and nuclear compartments. The “relocalization” of the G proteins to the cytoplasm when cells are cultured suggests that transmembrane signalling may be regulated by cell differentiation and cell-cell and cell-extracellular matrix interactions. © 1996 Wiley-Liss, Inc.