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The evolution of crocodylians as sea dwellers remains obscure because living representatives are basically freshwater inhabitants and fossil evidence lacks crucial aspects about crocodylian occupation of marine ecosystems. New fossils from marine deposits of Peru reveal that crocodylians were habitual coastal residents of the southeastern Pacific (SEP) for approximately 14 million years within the Miocene (ca 19 to 5 Ma), an epoch including the highest global peak of marine crocodylian diversity. The assemblage of the SEP comprised two long and slender-snouted (longirostrine) taxa of the Gavialidae: the giant Piscogavialis and a new early diverging species, Sacacosuchus cordovai. Although living gavialids (Gavialis and Tomistoma) are freshwater forms, this remarkable fossil record and a suite of evolutionary morphological analyses reveal that the whole evolution of marine crocodylians pertained to the gavialids and their stem relatives (Gavialoidea). This adaptive radiation produced two longirostrine ecomorphs with dissimilar trophic roles in seawaters and involved multiple transmarine dispersals to South America and most landmasses. Marine gavialoids were shallow sea dwellers, and their Cenozoic diversification was influenced by the availability of coastal habitats. Soon after the richness peak of the Miocene, gavialoid crocodylians disappeared from the sea, probably as part of the marine megafauna extinction of the Pliocene. [ABSTRACT FROM AUTHOR]

The thread blight disease (TBD) of cacao ( Theobroma cacao ) in the department of Amazonas, Peru was recently reported to be caused by Marasmius tenuissimus (sect. Neosessiles). This same species is known to be the main causal agent of TBD in West Africa. However, some morphological characteristics, such as the presence of rhizomorphs, the almost exclusively white color, and pileus sizes less than 5 mm, among others, differ to the description of M. tenuissimus. Therefore, we aimed to conduct a taxonomic revision of the cacao-TBD causal agent in Peru, by using thorough micro and macro morphological, phylogenetic, and nuclear and mitochondrial genomic approaches. We showed that the causal agent of TBD of cacao in Amazonas, Peru, belongs to a new species, Marasmius infestans sp. nov. This study enriches our knowledge of species in the sect. Neosessiles, and strongly suggests that the M. tenuissimus species complex is highly diverse., Competing Interests: No competing interests were disclosed., (Copyright: © 2024 Huamán-Pilco AF et al.)

Importance: Previous studies have suggested that oral lactoferrin enhances diversity in the gut microbiota in infants while inhibiting the growth of opportunistic pathogens. However, the effect of lactoferrin on infant gut microbiota over time has yet to be thoroughly studied. Our study suggests that lactoferrin oral treatment in infants aged 12-18 months does not affect gut microbiome diversity and composition over time. To our knowledge, this is the first study to report the effect of lactoferrin on infant gut microbiome composition over time and helps elucidate its impact on infant health and its therapeutic potential., Competing Interests: The authors declare no conflict of interest.

This research assessed carbon and nutrient burial during the past ~60 years within a Peruvian coastal marsh ecosystem affected by anthropogenic activities, by examining total organic carbon (TOC), total nitrogen (TN) and isotopes (δ 13 C and δ 15 N) tracers in two dated sediment cores. Significantly higher TOC and TN burial, up to 416.4 ± 65.0 and 0.7 ± 0.1 g m -2  year -1 respectively, were observed after an uncontrolled urban expansion starting in the early 1970's to the 1990's. The TOC and TN burial rates were up to twofold higher than those observed for preserved coastal marshes. Furthermore, the decreased δ 13 C values (-16.1 ± 0.6 ‰) and increasing δ 15 N values (+10.6 ± 2.6 ‰) indicate higher deposition of algal material and urban sewage during the same period. The higher burial rates during 1970's-1990's and reduced rates thereafter evidenced the role of coastal marsh ecosystems plays in sequestering carbon and nutrients., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The Rimac river is the main source of water for Lima, Peru's capital megacity. The river is constantly affected by different types of contamination including mine tailings in the Andes and urban sewage in the metropolitan area. In this work, we aim to produce the first characterization of aquatic bacterial communities in the Rimac river using a 16S rRNA metabarcoding approach which would be useful to identify bacterial diversity and potential understudied pathogens. We report a lower diversity in bacterial communities from the Lower Rimac (Metropolitan zone) in comparison to other sub-basins. Samples were generally grouped according to their geographical location. Bacterial classes Alphaproteobacteria, Bacteroidia, Campylobacteria, Fusobacteriia, and Gammaproteobacteria were the most frequent along the river. Arcobacter cryaerophilus (Campylobacteria) was the most frequent species in the Lower Rimac while Flavobacterium succinicans (Bacteroidia) and Hypnocyclicus (Fusobacteriia) were the most predominant in the Upper Rimac. Predicted metabolic functions in the microbiota include bacterial motility and quorum sensing. Additional metabolomic analyses showed the presence of some insecticides and herbicides in the Parac-Upper Rimac and Santa Eulalia-Parac sub-basins. The dominance in the Metropolitan area of Arcobacter cryaerophilus, an emergent pathogen associated with fecal contamination and antibiotic multiresistance, that is not usually reported in traditional microbiological quality assessments, highlights the necessity to apply next-generation sequencing tools to improve pathogen surveillance. We believe that our study will encourage the integration of omics sciences in Peru and its application on current environmental and public health issues., Competing Interests: The authors have declared that no competing interests exist.

The understanding of COVID-19, caused by the SARS-CoV-2, is essential to improve evidence-based public health policies. The effective reproductive number (Rt) in Peru was estimated using information from 113 complete genomes sequenced by the Instituto Nacional de Salud del Perú (INS), available in the GISAID public database. The Rt trend during March and April of 2020 was found to be similar to results from other epidemiological reports. The Rt decreased during the first two weeks of March. Its lowest value was reported during the week after the quarantine began. The Rt increased moderately after the second week of April. The implication of early decisions taken to mitigate the transmission are discussed. Genomic surveillance will be necessary to understand the transmission and evolution of SARS-CoV-2 in Peru, and will complement the epidemiological information.

Western South America was one of the worldwide cradles of civilization. The well-known Inca Empire was the tip of the iceberg of an evolutionary process that started 11,000 to 14,000 years ago. Genetic data from 18 Peruvian populations reveal the following: 1) The between-population homogenization of the central southern Andes and its differentiation with respect to Amazonian populations of similar latitudes do not extend northward. Instead, longitudinal gene flow between the northern coast of Peru, Andes, and Amazonia accompanied cultural and socioeconomic interactions revealed by archeology. This pattern recapitulates the environmental and cultural differentiation between the fertile north, where altitudes are lower, and the arid south, where the Andes are higher, acting as a genetic barrier between the sharply different environments of the Andes and Amazonia. 2) The genetic homogenization between the populations of the arid Andes is not only due to migrations during the Inca Empire or the subsequent colonial period. It started at least during the earlier expansion of the Wari Empire (600 to 1,000 years before present). 3) This demographic history allowed for cases of positive natural selection in the high and arid Andes vs. the low Amazon tropical forest: in the Andes, a putative enhancer in HAND2-AS1 (heart and neural crest derivatives expressed 2 antisense RNA1, a noncoding gene related to cardiovascular function) and rs269868-C/Ser1067 in DUOX2 (dual oxidase 2, related to thyroid function and innate immunity) genes and, in the Amazon, the gene encoding for the CD45 protein, essential for antigen recognition by T and B lymphocytes in viral-host interaction., Competing Interests: The authors declare no competing interest.