Marine litter pollution in a subantarctic beach of the Strait of Magellan, Punta Arenas, Chile.

This study assessed the presence of marine litter along the beach of the city of Punta Arenas, Chile. The sampling period coincided with the COVID-19 pandemic. A total of 239 plastic waste items were identified out of a total of 638 litter items. The Clean Coast Index reported within this study ranged from Clean (CCI 2-5) to Extremely dirty (CCI >20), especially near the port. The majority of litter items has been classified as originating from varied origins, as it is not possible to pinpoint a precise origin in most items. The results indicate that the predominant plastic litter in Punta Arenas is PVC. The results are discussed in relation to the sources and composition of the residues, the morpho dynamics of the coast, and the CCI is compared with other locations around the globe.

An outsider on the Antarctic Peninsula: A new record of the non-native moth Plodia interpunctella (Lepidoptera: Pyralidae).

We report the first record of the microlepidopteran Plodia interpunctella beyond the South Shetland Islands at the Chilean Yelcho scientific station (64°52'33.1428″ S; 63°35'1.9572″ W), Doumer Island, close to the west coast of the Antarctic Peninsula. It is notable that P. interpunctella, a globally distributed stored product pest species, exhibits a remarkable capacity for prolonged viability within food storage facilities. The dual challenges of food transportation and storage in the context of Antarctica's challenging operational conditions may have facilitated P. interpunctella's initial arrival to the Antarctic region. Non-perishable food items, such as grains, flour and rice, provide practical options for the bulk food transportation and storage required in the long-term operation of Antarctic research stations. The presence of P. interpunctella in Antarctica, even if restricted to synanthropic environments within buildings, is a clear threat to Antarctic biodiversity, not only through being an invasive species itself but also as a potential vector for other non-native species (bacteria, acari, between others.), which could carry diseases to the native species.

S-nitrosylation regulates VE-cadherin phosphorylation and internalization in microvascular permeability.

The adherens junction complex, composed mainly of vascular endothelial (VE)-cadherin, ß-catenin, p120, and γ-catenin, is the main element of the endothelial barrier in postcapillary venules.S-nitrosylation of ß-catenin and p120 is an important step in proinflammatory agents-induced hyperpermeability. We investigated in vitro and in vivo whether or not VE-cadherin isS-nitrosylated using platelet-activating factor (PAF) as agonist. We report that PAF-stimulates S-nitrosylation of VE-cadherin, which disrupts its association with ß-catenin. In addition, based on inhibition of nitric oxide production, our results strongly suggest that S-nitrosylation is required for VE-cadherin phosphorylation on tyrosine and for its internalization. Our results unveil an important mechanism to regulate phosphorylation of junctional proteins in association with S-nitrosylation.

Assessing the micro-phytoplankton response to nitrate in Comau Fjord (42°S) in Patagonia (Chile), using a microcosms approach.

Anthropogenic (aquaculture) changes in environment nutrient concentrations may affect phytoplankton (biomass and taxa composition) in marine coastal waters off the Chilean Patagonia. The effects of adding nitrate (NO3(-)) to natural phytoplankton assemblages were evaluated considering biomass, cell abundance, and taxonomic composition. Microcosm experiments were performed in the spring, summer, and winter in the Comau Fjord located in Subantarctic Patagonia. At the end of the experiments, NO3(-) decreased rapidly and was undetectable in treatments, indicating a strong NO3(-) deficiency associated with an exponential increase in Chl-a concentrations, particulate organic nitrogen, and carbon in these treatments. Moreover, given the depleted nitrate concentrations of the spring and summer experiments, the micro-phytoplankton taxa structure shifted from mixed diatom and dinoflagellate assemblages (Ceratium spp., Dinophysis spp., Coscinodiscus sp., Rhizosolenia pungens) to assemblages dominated by blooms of the classic chain-forming diatoms found in temperate and cold waters such as Chaetoceros spp., Skeletonema spp., and Thalassiosira spp. Thus, nitrogen sources (i.e., nitrate, ammonia) may influence phytoplankton abundance and biomass accumulation dynamics in the northern section of Patagonia. It also emphasizes the importance of diatom taxa in regards to the short-term response of phytoplankton to changing environmental nutrient conditions due to natural (decreasing freshwater stream flow) and anthropogenic (aquaculture) events. This situation may be one of the future scenarios in the Patagonian fjords, thus stressing the needs for active environmental monitoring and impact assessment.