X-ray microtomography provides first data about the feeding behaviour of an endangered lizard, the Montserrat galliwasp (Diploglossus montisserrati)

Development of mucoadhesive Timolol loaded chitosan-nanocomposite to treat glaucoma

Timolol Maleate is an aqueous soluble β-blocker antiglaucoma drug used to suppress intraocular pressure. Several commercially available ocular formulations are not effective in delivering to the target site due to their water-soluble property and low mucoadhesiveness. Hence, there is a requirement for a highly mucoadhesive drug-loaded nanocomposite to suppress intraocular pressure with enhanced bioavailability. Herein, we have prepared a mucoadhesive Timolol-loaded graphene quantum dot-chitosan-nanocomposite to treat glaucoma in response to lysozyme, secreted in the tear fluid. The as-prepared nanocomposite has been characterized through high resolution-transmission electron microscopic, X-ray photoelectron spectroscopic, X-ray diffraction, and Fourier transform infrared spectral studies. The nanocomposite showed 93.74 % encapsulation efficiency with a loading capacity of 7.73 %. Further, 89.26 %, 95.62 %, and 99.29 % of drug release were observed from the nanocomposite in the presence of 1, 1.5, and 2 mg/mL of lysozyme. The mucoadhesion property has been confirmed by the increment in the particle size, fluorescence spectral variations, and Fourier transform infrared spectroscopic studies in the presence of mucin nanoparticles of size 291 nm. Interestingly, mucoadhesion has been demonstrated by pointing to the quenching in the luminescence of mucin. Further, in vitro biocompatibility assay on human corneal epithelial cells showed ≥80 % cell viability. Hence, this study offers the utilization of naturally secreting enzymes for drug delivery applications instead of uncontrolled pH and temperature-triggered releases.

Archaeological occurrences of terrestrial herpetofauna in the insular Caribbean: cultural and biological significance

Although the importance of the archaeological record for addressing questions of biodiversity is gaining ground, its relevance for describing past faunal communities is still under-exploited, particularly for the most under-documented areas and species. Among the most poorly documented taxa are reptiles and amphibians, which are rarely studied in detail in the archaeological record, even in tropical areas where most of these species occur today. Here I evaluate the archaeological and paleontological significance of reptiles and amphibians from the Indigenous archaeological record of the insular Caribbean. Quantitative (bone counts) and qualitative (taxonomic identification) analyses allow researchers to discuss the role of herpetofauna in the subsistence strategies of Indigenous populations as well as their interest for assessing past insular biodiversity. This overview sheds light on both the poor representation of herpetofaunal taxa in Caribbean archaeological deposits and trends in the potential exploitation of reptiles and amphibians by Indigenous populations. In terms of paleoecology, the presented results reveal strong regional differences in the quality and density of data as well as the inadequacy of available archaeofaunal data for addressing questions of past biodiversity.

A fossil Diploglossus (Squamata, Anguidae) lizard from Basse-Terre and Grande-Terre Islands (Guadeloupe, French West Indies)

Today, Diploglossine lizards (Anguidae) are common on the Greater Antillean Islands (West Indies), where they are represented by many endemic species. However these lizards are very rare on the Lesser Antillean Islands, where they are only represented by a single species, the Montserrat galliwasp (Diploglossus montisserrati). Here, we show that diploglossine lizards were present in the past on other Lesser Antillean islands, by reporting the discovery of Anguidae fossil remains in two Amerindian archaeological deposits and in a modern deposit. These remains are compared to skeletons of extant diploglossine lizards, including D. montisserrati, using X-ray microtomography of the type specimen of this critically endangered lizard. We also conducted a histological study of the osteoderms in order to estimate the putative age of the specimen. Our results show that the fossil specimens correspond to a member of the Diploglossus genus presenting strong similarities, but also minor morphological differences with D. montisserrati, although we postulate that these differences are not sufficient to warrant the description of a new species. These specimens, identified as Diploglossus sp., provide a new comparison point for the study of fossil diploglossine lizards and reflect the historical 17(th) century mentions of anguid lizards, which had not been observed since.