Aim: The frog genus Rheobates (Anura: Aromobatidae) is endemic to mid-elevations in the Colombian Andes. Our aim was to evaluate the role of the northern Andean high peaks and the low Magdalena ...Valley in creating barriers to dispersal and promoting vicariance within Rheobates. Location: Three disjunct mid-elevation flanks of the northern Colombian Andes: the eastern and western flanks of the Eastern Cordillera, separated by high mountain peaks, and the eastern flank of the Central Cordillera, separated from the Eastern Cordillera by the arid Magdalena Valley. Methods: We analysed mitochondrial and nuclear DNA sequences from 37 individuals of Rheobates to infer their phylogenetic relationships, divergence times and ancestral areas. We used species distribution models to test the role of climatic variables in determining the present geographical boundaries of the species. Results: The phylogeny of Rheobates is largely predicted by geography, with one population from the eastern flank of the Eastern Cordillera sharing a most recent common ancestor with all other Rheobates 21 million years ago (Ma; 95% credible interval 31-10 Ma). Populations in the Central Cordillera were monophyletic, isolated across the Magdalena Valley with a divergence time estimated at 13 Ma (19-7 Ma). We also detected one recent crossing of the Eastern Cordillera, along with unanticipated latitudinal phylogeographical structure within the western flank of the Eastern Cordillera. Environmental niche tests indicated that the Magdalena Valley and the high peaks of the Eastern Cordillera are significant environmental barriers for Rheobates populations. Main conclusions: Diversification in Rheobates coincided with the early Miocene uplift of Colombia's Eastern Cordillera and the hypothesized onset of aridity in the Magdalena Valley during the middle Miocene. Our study offers broad support for the classic mountain orogeny model of vicariant divergence, but suggests that lowland habitat heterogeneity also played a long-term role in promoting vicariance, despite a long history of palaeoclimatic fluctuations.
Colombia hosts the second highest amphibian species diversity on Earth, yet its fauna remains poorly studied, especially using molecular genetic techniques. We present the results of the first ...wide-scale DNA barcoding survey of anurans of Colombia, focusing on a transect across the Eastern Cordillera. We surveyed 10 sites between the Magdalena Valley to the west and the eastern foothills of the Eastern Cordillera, sequencing portions of the mitochondrial 16S ribosomal RNA and cytochrome oxidase subunit 1 (CO1) genes for 235 individuals from 52 nominal species. We applied two barcode algorithms, Automatic Barcode Gap Discovery and Refined Single Linkage Analysis, to estimate the number of clusters or "unconfirmed candidate species" supported by DNA barcode data. Our survey included ~7% of the anuran species known from Colombia. While barcoding algorithms differed slightly in the number of clusters identified, between three and ten nominal species may be obscuring candidate species (in some cases, more than one cryptic species per nominal species). Our data suggest that the high elevations of the Eastern Cordillera and the low elevations of the Chicamocha canyon acted as geographic barriers in at least seven nominal species, promoting strong genetic divergences between populations associated with the Eastern Cordillera.
Background Leishmaniasis, a neglected disease and public health concern, is associated with various factors such as biological, social, economical conditions and climate, increasing the risk of human ...infection. Understanding the population dynamics of the vectors, like Pintomyia longiflocosa, and its relationship with ecological variables is crucial for developing effective strategies to control sand fly populations and combat cutaneous leishmaniasis in a tropical country like Colombia. Methodology Adult sand flies were collected in three different sample locations: outdoor, indoor, and peri-domestic areas in three houses located in the rural settlement of Campoalegre (Huila) between February 2020 and February 2021, using the CDC light traps. The sand fly density was quantified and associated with the sample locations and the sampling months using Analysis of Variance and Pearson correlations. Principal findings In the period of the sample, 98.86% of sand fly collected was identified as Pi. longiflocosa. The density of this species was significantly different between males and females, the latter contributing more to density in all sample locations (P<0.0001). The outdoor was the sample location with the highest and most significative density in this study (70%, P = 0.04). The density of these sand flies is related to the seasonality of Campoalegre, revealing a density peak from February and June to October (P < 0.05). Finally, precipitation is the environmental variable prominently linked to the density pattern, showing a negative correlation with it. Months with the highest precipitations show the lowest values of Pi. longiflocosa abundance. Conclusions/Signicance Our investigation reveals a inverse correlation between precipitation levels and the abundance of Pi. longiflocosa in Campoalegre (Huila), particularly in outdoor areas. This suggests that vector control strategies to periods of reduced precipitation in outdoor settings could offer an effective approach to minimizing cases of cutaneous leishmaniasis in the region.
The loggerhead sea turtle (Caretta caretta) is sensitive to climate change and is responding by colonising the Western Mediterranean. To understand the rapid nesting increase in recent years in ...Spain, we sampled 45 hatchlings from 8 nests between 2016 and 2019. We sequenced a mtDNA D-loop region, genotyped 2291 SNPs using 2bRAD and collected data on clutch size, hatching success, and incubation duration. We confirmed that the colonisation has a Mediterranean and Atlantic mixed origin and we detected that these nests were laid by different females, except for two nests within the same season. Our results suggest that the recent increase in nesting is due to an increase in the number of colonising individuals rather than females born in the same area returning to breed. We hypothesize that this increase in the number of colonisers results from successful conservation efforts, feminisation of the populations of origin and earlier sexual maturation. However, the percentage of offspring females produced in Spain suggests that future returning individuals will aid to the settlement of the new population. These results allow defining the current status of this colonisation although future efforts are needed to detect remigrants to confirm the establishment of a resident population.
Mating and spawning usually take place during the warmer months of the year, although in some areas, mainly in the western Caribbean, the breeding activity is continuous at low reproduction levels ...throughout the year (Avila-Poveda and Baqueiro-Cardenas, 2009; Aldana-Aranda et al., 2014; Boman et al., 2018). ...some populations migrate seasonally from open waters to shallower waters for spawning (Appeldoorn, 1993). Estimates of abundance and density of queen conch were made from diver-based visual surveys along 4 strip-transects of 30 × 8 m. Data collected during observations included georeferencing, depth, habitat type (seagrass habitat is not present on Serrana bank, probably replaced by the ruffled form of Lobophora variegata, see additional details in Sánchez et al., 2005, 2019), zoning regarding conservation, and density of adults and juveniles of the conch estimated as number of individuals per hectare (ind. ha−1). Statistical Analysis and Spatial Description To establish relationships between depth and adult and juvenile densities of the queen conch, Spearman rank correlations were calculated for the five different samplings given the lack of normality of the data (Shapiro Wilk test). ...open areas presented the highest densities of the snail, indicating preliminarily that the definition of conservation areas have not been efficient for the protection of the resource.
Selective activation of the neuropeptide Y (NPY)2 receptor to suppress appetite provides a promising approach to obesity management. A selective NPY2 polyethylene glycol-conjugated (PEGylated) ...peptide agonist is described that consists of a peptide core corresponding to residues 13 to 36 of human peptide YY (PYY) and a nonpeptidic moiety (2-mercaptonicotinic acid) at the peptide N terminus that is derivatized with 20-kDa monomethoxypolyethylene glycol. The PEGylated peptide elicits a dose-dependent reduction in food intake in lean C57BL/6 mice and Wistar rats that persists for 72 and 48 h, respectively. The effect on food intake in lean C57BL/6 mice is blocked by the selective NPY2 antagonist BIIE0246 (N-(1S)-4-(aminoiminomethyl)amino-1-2-(3,5-dioxo-1,2-diphenyl-1,2,4-triazolidin-4-yl)ethylaminocarbonylbutyl-1-2-4-(6,11-dihydro-6-oxo-5H-dibenzb,eazepin-11-yl)-1-piperazinyl-2-oxoethyl-cyclopentaneacetamide formate). A dose-dependent reduction in body weight in diet-induced obese (DIO) mice is seen following daily dosing for 14 days. The reduction in body weight is sustained following dosing for 40 days, and it is accompanied by an increase in plasma adiponectin. Improvements in glucose disposal and in plasma insulin and glucose levels that are risk factors for type II diabetes are observed following once-daily subcutaneous dosing in DIO mice. The results provide evidence from two animal species that the long-acting selective NPY2 peptide agonist has potential for obesity management.
Type 2 diabetes is characterized by reduced insulin secretion from the pancreas and overproduction of glucose by the liver. Glucagon-like peptide-1 (GLP-1) promotes glucose-dependent insulin ...secretion from the pancreas, while glucagon promotes glucose output from the liver. Taking advantage of the homology between GLP-1 and glucagon, a GLP-1/glucagon hybrid peptide, dual-acting peptide for diabetes (DAPD), was identified with combined GLP-1 receptor agonist and glucagon receptor antagonist activity. To overcome its short plasma half-life DAPD was PEGylated, resulting in dramatically prolonged activity in vivo. PEGylated DAPD (PEG-DAPD) increases insulin and decreases glucose in a glucose tolerance test, evidence of GLP-1 receptor agonism. It also reduces blood glucose following a glucagon challenge and elevates fasting glucagon levels in mice, evidence of glucagon receptor antagonism. The PEG-DAPD effects on glucose tolerance are also observed in the presence of the GLP-1 antagonist peptide, exendin(9-39). An antidiabetic effect of PEG-DAPD is observed in db/db mice. Furthermore, PEGylation of DAPD eliminates the inhibition of gastrointestinal motility observed with GLP-1 and its analogues. Thus, PEG-DAPD has the potential to be developed as a novel dual-acting peptide to treat type 2 diabetes, with prolonged in vivo activity, and without the GI side-effects.
Selective activation of the NPY2 receptor to suppress appetite provides an approach to obesity management. Selective NPY2 PEGylated peptide agonists are described that consist of a peptide core ...corresponding to residues 25−36 of PYY and a nonpeptidic moiety at the peptide N-terminus that contributes to in vitro potency and in vivo efficacy and provides a PEGylation site. The lead peptide elicits a dose-dependent reduction of food intake in lean mice and of food intake, body weight, and fat mass in DIO mice.
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