http://hdl.handle.net/11422/13 2026-07-30T01:40:00Z 2026-07-30T01:40:00Z http://hdl.handle.net/11422/29858 2026-07-29T18:00:54Z 2025-07-18T00:00:00Z

Title: Influência de Estressores Associados às Mudanças Climáticas no Desenvolvimento Larval de Platynereis dumerilii (Annelida: Nereididae) Author(s)/Inventor(s): Fonseca, Lucas Alves da Advisor: Ruta, Christine Abstract: Changes in oceanic patterns driven by global climate change have especially affected the early life stages of marine organisms. Considering the scarcity of knowledge regarding the early development of annelids under the effects of climate change and their susceptibility, the present study aims to evaluate the isolated and synergistic effects of temperature and salinity on early development, survival, and the occurrence of morphological abnormalities in Platynereis dumerilii larvae. Three laboratory experiments were conducted: (i) salinity, with treatments of 35 (control), 30, and 25 at 18 °C; (ii) temperature, with treatments of 18 °C (control), 25 °C, 30 °C, and 35 °C at a constant salinity of 35; and (iii) a synergistic experiment, with seven combinations between 18 °C and 35 °C and salinities of 35, 30, and 25. The larvae were obtained through spontaneous fertilizations synchronized with the lunar cycle. Larval development was monitored up to the nectochaete stage. The results indicated that moderate temperatures (25 °C and 30 °C) accelerate development, while reduced salinities (25) cause significant delays and an increase in the incidence of morphological abnormalities. Exposure to 35 °C resulted in total mortality, suggesting a thermal limit for the species. In the combined treatments, moderate conditions favored development, while extreme combinations (35 °C/25) were lethal. The findings contribute to advancing knowledge on the responses of soft-bodied marine invertebrates to climate change, particularly within the phylum Annelida, an area still underexplored compared to studies on calcifying organisms and may serve as a reference for future experimental studies. Publisher: Universidade Federal do Rio de Janeiro Type: Dissertação

2025-07-18T00:00:00Z http://hdl.handle.net/11422/29856 2026-07-29T17:50:41Z 2025-09-19T00:00:00Z

Title: Efeitos das mudanças climáticas na capacidade de regeneração de Platynereis dumerilii (annelida: nereididae) Author(s)/Inventor(s): Gutiérrez, Delfina Advisor: Ruta, Christine Abstract: Anthropogenic climate change affects marine environments through alterations in salinity, rising temperatures, and ocean acidification. Understanding the effects of these factors on organisms is essential, although groups such as annelids remain underrepresented in research. The annelid Platynereis dumerilii stands out as an experimental model and exhibits posterior regenerative capacity, a key process following physical damage but potentially associated with fitness costs. This study evaluated the effects of projected variations in salinity, temperature, and pH, based on IPCC (2019, 2023) scenarios, on the regeneration of P. dumerilii. Temperatures of 18°C (control), 25°C, 30°C, and 33°C; salinities of 35 (control), 30, and 25; and pH values of 7.9 (control) and 7.6 were tested. Organisms with 30–40 segments and 3–4 months of age were amputated and monitored for five days, a period sufficient for complete regeneration under control conditions. Regeneration occurrence, survival, and the formation of anomalies were analysed using Generalized Linear Models. Results revealed that the regeneration of P. dumerilii is sensitive to future climate scenarios. Reduced salinity slightly delayed regeneration without affecting survival or inducing anomalies. Elevated temperature accelerated regeneration but caused anomalies at 30°C and mortality above this threshold. Lowered pH reduced survival and suggested a decelerating effect on regeneration. This study contributes to the understanding of climate change impacts on marine invertebrates and expands current knowledge on regeneration in annelids. Publisher: Universidade Federal do Rio de Janeiro Type: Dissertação

2025-09-19T00:00:00Z http://hdl.handle.net/11422/29842 2026-07-28T22:22:00Z 2025-03-11T00:00:00Z

Title: Sistemática e filogenia do gênero Centroceras Kützing (Ceramiaceae, Rhodophyta) Author(s)/Inventor(s): Menegale, Alda Carolina Lambone Advisor: Barros Barreto, Maria Beatriz Barbosa de Abstract: The genus Centroceras comprises filamentous marine red algae with complete cortication of the thallus, originating from periaxial cells, which consistently divide into two acropetal and one basipetal cells. Although morphological characteristics are traditionally employed to differentiate its species, the overlapping of these traits hampers accurate delimitation within the genus. This identification challenge has led to the adoption of phylogenetic techniques, which have revealed cryptic diversity within the group. Furthermore, the genus has undergone significant nomenclatural changes, particularly following the introduction of molecular biology. The first taxonomic revision of the genus Centroceras in the post-DNA era of macroalgal taxonomy revealed that Centroceras clavulatum (Agardh) Montagne is not a single species, but rather a species complex. Currently, the genus includes 18 species, several of which have been recently recognized. This study aimed to revise and analyze the systematics of the genus Centroceras using phylogenetic tools to refine the group’s taxonomic classification. Novel sequences were generated and analyzed for the Brazilian coast, in addition to data retrieved from GenBank, using two molecular markers: rbcL and COI-5P. The results indicated a need for taxonomic reorganization within the genus Centroceras. A key finding was the identification of the C. gasparrinii (Meneghini) Kützing complex, which possibly encompasses five distinct species, and the reinstatement of C. macracanthum Kützing for the Brazilian coast. Additionally, the distribution of C. gasparrinii was confirmed in both the Mediterranean Sea and the Sea of Japan. Molecular analyses also led to the identification of a new species from the Brazilian coast, occurring in two specific locations in Bahia and Rio de Janeiro. Furthermore, the results reinforced that morphology alone does not meet the criteria required for accurate species recognition within this genus. Morphological approaches may result in species underreporting, hinder the discovery of new taxa, and lead to nomenclatural misassignments. Based on molecular data, 16 species are currently recognized at the molecular level. When morphologically based species are included, the total number reaches 23. This revision excludes the occurrence of C. micracanthum sensu Won, Cho & Fredericq and C. gasparrinii from the Brazilian marine flora, as previously suggested by other studies. The study concludes that the integration of molecular data and phylogenetic methods, coupled with careful nomenclatural revision, allows for a more precise delimitation of Centroceras species, revealing a complex diversity and providing a more robust and up-to-date nomenclatural reorganization for the genus. In summary, this study significantly contributes to the understanding of the diversity and phylogeny of the genus Centroceras, highlighting the importance of molecular data in taxonomy and offering clearer insights into species distribution and identification, including the detection of novel species and the implementation of necessary nomenclatural adjustments. Publisher: Universidade Federal do Rio de Janeiro Type: Dissertação

2025-03-11T00:00:00Z http://hdl.handle.net/11422/29839 2026-07-28T17:43:42Z 2025-03-31T00:00:00Z

Title: Salmonella sp. em águas superficiais de regiões agropecuárias do Estado do Rio de Janeiro: ocorrência, identidade, virulência e resistência a antimicrobianos Author(s)/Inventor(s): Moura, Vinicius de Carvalho Advisor: Bonelli, Raquel Regina Abstract: Salmonella sp. is a bacterial genus of the Enterobacteriaceae family, composed of two species: S. bongori and S. enterica, the latter being of greater clinical and economic relevance due to its subspecies S. enterica subsp. enterica (I), which is responsible for causing infections in warm-blooded animals such as humans, cattle, and poultry. This pathogen plays a central role in the context of Waterborne and Foodborne Diseases (WFDs), impacting human, animal, and environmental health. Its association with hosts such as cattle and broiler chickens makes agricultural production regions potential epicenters of dissemination, either through water sources or food products. In this context, the aim of this study was to investigate the occurrence of Salmonella in water bodies in agricultural regions of the State of Rio de Janeiro, focusing on area impacted by cattle farming, broiler chicken production, and horticulture, as well as to characterize aspects of the isolates, such as serovars, virulome, resistome, and plasmidome. A total of 313 water samples were collected from rivers, streams, and creeks within the hydrographic basins of Médio Paraíba do Sul (MPS; marked by cattle farming and horticulture) and Piabanha (Pb; with intense horticulture and broiler chicken farming). From 181 (58%) of these samples, Salmonella was successfully isolated. After isolation, screening by RAPD, sequencing of up to five isolates per water sample, and bioinformatics analyses, 308 isolates were selected as representatives of the collection (all those that were determined to be non-clonal within each evaluated water sample). Among them, 46 serovars were identified, with emphasis on Panama (44/308), Newport (43/308), Typhimurium (27/308), and Saphra (23/308), with the first three serovars present in both basins and the last one exclusive to MPS. A total of 146 virulence genes were detected, including operons such as spv, pef, rck, and yopJ/yopP, which were associated with plasmids of the incompatibility group IncF, commonly linked to invasive virulence genes. Additionally, resistance mechanisms to β-lactams, aminoglycosides, tetracyclines, phenicols, quinolones, sulfonamide-trimethoprim were identified in chromosomal genes (mutations in gyrA and ramR) and in contigs associated with plasmid markers such as Col440I (containing qnrB19), ColRNAI (aph(3'')-Ib, aph(6)-Id, sul2, and tet(A)), IncC/A2 (sul2 and tet(A)), IncFIC (floR and tet(A)), IncR, and IncX (blaTEM-1, blaTEM-135, and tet(A)), as well as genes blaCMY-2, aadA1, aadA2, tet(B), tet(C), qnrS1, and dfrA in plasmids without a defined Inc group. The fosA7 gene (fosfomycin) was found in the genome of all Saphra isolates. The results of this study provide unique insights into the phylogeny, virulence, resistance, and plasmidome of Salmonella in water bodies of agricultural regions in Rio de Janeiro, contributing to a better understanding of the dissemination and adaptation of this pathogen in this region. Publisher: Universidade Federal do Rio de Janeiro Type: Dissertação

2025-03-31T00:00:00Z