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Micro- and nanoplastics are widespread throughout the world. In particular, polyethylene (PE) and polyethylene terephthalate or polyester (PET) are two of the most common polymers, used as plastic bags and textiles. To analyze the toxicity of these two polymers, oligomers with different numbers of units were used as models. The use of oligomers as polymeric templates has been used previously with success. We started with the monomer and continued with different oligomers until the chain length was greater than two nm. According to the results of quantum chemistry, PET is a better oxidant than PE, since it is a better electron acceptor. Additionally, PET has negatively charged oxygen atoms and can promote stronger interactions than PE with other molecules. We found that PET forms stable complexes and can dissociate the guanine-cytosine nucleobase pair. This could affect DNA replication. These preliminary theoretical results may help elucidate the potential harm of micro- and nanoplastics. [ABSTRACT FROM AUTHOR]

This article, published in Antarctic Science, discusses the risk of highly pathogenic avian influenza (HPAI) in the Southern Ocean and provides recommendations for prevention and control. HPAI outbreaks have resulted in the deaths of seabirds and marine mammals in various regions. The article emphasizes the importance of monitoring and early detection of HPAI, as well as taking precautions to prevent its spread. It provides guidelines for visitors to wildlife colonies, including maintaining distance from wildlife, practicing personal hygiene, and disinfecting equipment. The document also includes contact information for national competent authorities and organizations involved in Antarctic research. The recommendations aim to protect wildlife populations and prevent the spread of HPAI in the region. The article "Global dissemination of influenza A virus is driven by wild bird migration through arctic and subarctic zones" discusses the role of wild bird migration in the global spread of influenza A virus. It highlights the importance of arctic and subarctic zones as key areas for the transmission of the virus. The article also references other studies that examine the spread of avian influenza in different regions, including Azerbaijan, Antarctica, Chile, and Africa. It emphasizes the need for continued research and surveillance to better understand and manage the risk of avian influenza. [Extracted from the article]

Copyright of Revista de la Asociación Geológica Argentina is the property of Asociacion Geologica Argentina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Visitor Site Guidelines are the principal instruments guiding tourist activities and behaviour at intensively visited sites. These instruments attempt to minimize tourist impacts on Antarctic wildlife, including penguins. However, some recommendations still need to be reinforced by empirical research. Although penguins have enjoyed considerable research attention, a knowledge gap still exists regarding penguins' behavioural responses to realistic tourist activities, including talking sound, viewing distance and movement speed. To fill this gap, we conducted a series of experiments to simulate these activities on two penguin species breeding at an intensively visited site during the 2019–2020 season. We performed 106 replicates of passive and active human presence treatments. Responses varied between species, but active human presence consistently triggered significantly higher responses of strong vigilance behaviour. Our results reinforce Visitor Site Guidelines' recommendations of keeping quiet, moving slowly and increasing viewing distance if changes in behaviour are observed. We also recommend adopting a more conservative viewing distance in the early breeding season. Additional management-orientated empirical studies are needed, including on different species, sites and stages of the breeding season, as such results are valuable for strengthening tourism guidelines and assessing the efficacy of management measures under a post-COVID-19 scenario of increasing Antarctic tourism. [ABSTRACT FROM AUTHOR]

Research on immune response in polar fauna is gaining great importance due to different scenarios of environmental change. Total leukocyte counts in blood smears are one of the most widespread practices and provide useful information about the health status of individuals. However, there is no methodological agreement for these analyses. Total leukocyte counts can be performed at ×400 magnification in optical microscopy using 10,000 erythrocytes for standardizing. However, counting such number of erythrocytes is costly and time-consuming. Here, we describe a new technique to simplify leukocyte counts in blood smears from Antarctic wildlife based on the number of microscope fields instead of the number of erythrocytes which reduces considerably the time spent. We have counted total leukocytes using both methods in the three penguin species of the genus Pygoscelis—Adélie (P. adeliae), gentoo (P. papua), and chinstrap penguin (P. antarcticus)—and four Antarctic mammal species: crabeater seal (Lobodon carcinophaga), leopard seal (Hydrurga leptonyx), weddell seal (Leptonychotes weddellii), and southern elephant seal (Mirounga leonina) for validation. Our results show a high correlation between the total leukocyte counts using 10,000 erythrocytes or 10 microscope fields for standardizing. These results show the reliability of the latter method for counting the total number of leukocytes in different species of birds and mammals saving time and effort. [ABSTRACT FROM AUTHOR]

Copyright of Signata is the property of Presses Universitaires de Liege and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Fuentes, El Reventón Energético is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Over evolutionary time, pathogen challenge shapes the immune phenotype of the host to better respond to an incipient threat. The extent and direction of this selection pressure depend on the local pathogen composition, which is in turn determined by biotic and abiotic features of the environment. However, little is known about adaptation to local pathogen threats in wild animals. The Gentoo penguin (Pygoscelis papua) is a species complex that lends itself to the study of immune adaptation because of its circumpolar distribution over a large latitudinal range, with little or no admixture between different clades. In this study, we examine the diversity in a key family of innate immune genes—the Toll-like receptors (TLRs)—across the range of the Gentoo penguin. The three TLRs that we investigated present varying levels of diversity, with TLR4 and TLR5 greatly exceeding the diversity of TLR7. We present evidence of positive selection in TLR4 and TLR5 , which points to pathogen-driven adaptation to the local pathogen milieu. Finally, we demonstrate that two positively selected cosegregating sites in TLR5 are sufficient to alter the responsiveness of the receptor to its bacterial ligand, flagellin. Taken together, these results suggest that Gentoo penguins have experienced distinct pathogen-driven selection pressures in different environments, which may be important given the role of the Gentoo penguin as a sentinel species in some of the world's most rapidly changing environments. [ABSTRACT FROM AUTHOR]

Sexual segregation characterises many animal communities, and in seabirds (including penguins), foraging strategies are known to vary with sex. The forging strategies of Adélie penguins (Pygoscelis adeliae) have been studied to some extent in some Antarctic locations; however, sex-based differences in foraging in this species have only been studied in depth in East Antarctica. Therefore, in this study, we aim to determine whether sexual segregation drives the foraging ecology [in terms of foraging habitat and diet based on analysis of stable carbon (δ13C) and nitrogen (δ15N) isotopes, respectively] of Adélie penguins in the Antarctic Peninsula (Hope Bay) during the breeding season. Our results showed strong sexual isotopic spatial segregation. Females forage for more krill than fish in more offshore, pelagic waters in contrast to males which feed equally on both items in more inshore, benthic waters. These results suggest a link between foraging habitat and diet that differs according to sex, similar to that found in East Antarctica. Given these similarities, we hypothesise that the foraging ecology of Adélie penguins varies with sex throughout the Antarctic continent. Nevertheless, further research in other locations such as in western Antarctica is needed to confirm this hypothesis. [ABSTRACT FROM AUTHOR]

The personal, commercial, and scientific use of unmanned aerial systems (UAS) in Antarctica has increased dramatically in recent years. Due to the potential benefits for, and negative impacts to, sensitive Antarctic wildlife, the use of UAS (also called unmanned aerial vehicles (UAV), remotely piloted aircraft systems (RPAS) or drones) is a widely discussed topic. Accordingly, an assessment of the current state of UAS-wildlife response research and recommendations for future work is needed. This paper summarizes recent research and the expert opinion of several national Antarctic science programs in order to support Antarctic conservation policy discussions and inform forthcoming research. It encapsulates the current knowledge on the impact of UAS on Antarctic wildlife and the recommendations of the Action Group (AG) on ‘Development of a satellite-based, Antarctic-wide, remote sensing approach to monitor bird and animal populations’ of the Scientific Committee on Antarctic Research (SCAR) for the compilation of guidelines. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ornithology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)