Schinus terebinthifolius leaf extract causes midgut damage, interfering with survival and development of Aedes aegypti larvae

In this study, a leaf extract from Schinus terebinthifolius was evaluated for effects on survival, development, and midgut of A. aegypti fourth instar larvae (L4), as well as for toxic effect on Artemia salina. Leaf extract was obtained using 0.15 M NaCl and evaluated for phytochemical composition and lectin activity. Early L4 larvae were incubated with the extract (0.3–1.35%, w/v) for 8 days, in presence or absence of food. Polymeric proanthocyanidins, hydrolysable tannins, heterosid and aglycone flavonoids, cinnamic acid derivatives, traces of steroids, and lectin activity were detected in the extract, which killed the larvae at an LC50 of 0.62% (unfed larvae) and 1.03% (fed larvae). Further, the larvae incubated with the extract reacted by eliminating the gut content. No larvae reached the pupal stage in treatments at concentrations between 0.5% and 1.35%, while in the control (fed larvae), 61.7% of individuals emerged as adults. The extract (1.0%) promoted intense disorganization of larval midgut epithelium, including deformation and hypertrophy of cells, disruption of microvilli, and vacuolization of cytoplasms, affecting digestive, enteroendocrine, regenerative, and proliferating cells. In addition, cells with fragmented DNA were observed. Separation of extract components by solid phase extraction revealed that cinnamic acid derivatives and flavonoids are involved in larvicidal effect of the extract, being the first most efficient in a short time after larvae treatment. The lectin present in the extract was isolated, but did not show deleterious effects on larvae. The extract and cinnamic acid derivatives were toxic to A. salina nauplii, while the flavonoids showed low toxicity. S. terebinthifolius leaf extract caused damage to the midgut of A. aegypti larvae, interfering with survival and development. The larvicidal effect of the extract can be attributed to cinnamic acid derivatives and flavonoids. The data obtained using A. salina indicates that caution should be used when employing this extract as a larvicidal agent

Troponina no Infarto Agudo do Miocárdio sem Supradesnivelamento do Segmento ST: Uma Revisão Sistemática

This work presents a systematic review on the role of troponin in Non-ST Elevation Myocardial Infarction (NSTEMI). The introduction underscores the significance of troponin as a sensitive biomarker for myocardial injury, particularly in the context of NSTEMI. The methodology outlines a rigorous approach following PRISMA guidelines, including inclusion and exclusion criteria, database searches, and study quality assessment. The development section covers the analysis of results, highlighting diagnostic sensitivity, long-term prognostic value, and challenges in interpreting troponin levels. The conclusion underscores the clinical relevance of troponin, emphasizing its role in rapidly identifying patients, risk stratification, and prognosis in NSTEMI. The evolving diagnostic methodology and challenges to be addressed are also discussed, pointing towards future directions in research.Este trabalho apresenta uma revisão sistemática sobre o papel da troponina no Infarto Agudo do Miocárdio (IAM) sem Supradesnivelamento do Segmento ST. A introdução destaca a importância da troponina como biomarcador sensível de lesão miocárdica, especialmente em contextos de IAM sem supra de ST. A metodologia descreve a abordagem rigorosa seguindo as diretrizes do PRISMA, incluindo critérios de inclusão e exclusão, busca em bases de dados e avaliação da qualidade dos estudos. O desenvolvimento abrange a análise dos resultados, destacando a sensibilidade diagnóstica, prognóstico a longo prazo e desafios na interpretação dos níveis de troponina. A conclusão ressalta a relevância clínica da troponina, enfatizando seu papel na rápida identificação de pacientes, estratificação de risco e prognóstico em IAM sem supra de ST. Discute-se também a evolução da metodologia diagnóstica e desafios a serem abordados, apontando para direções futuras na pesquisa

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

<i>Aedes aegypti</i> L₄ larvae incubated for 12 h with <i>Schinus terebinthifolius</i> leaf extract (1.0%, w/v).

<p>(A) Larva eliminating the gut content covered by the peritrophic matrix. (B) Shrunken and pigmented midgut dissected from a larva incubated with the leaf extract. (C) Midgut dissected from a control larvae, after removal of gut content and peritrophic matrix, without apparent alterations. (D) Midgut dissected from a larva incubated with the leaf extract containing the 0.01 M phenylthiourea (PTU), a phenoloxidase inhibitor. (E) Midgut dissected from a larva incubated with 0.01 M PTU.</p

Toluidine Blue stained histological sections of the midgut of <i>Aedes aegypti</i> L4 from control (A) and incubated for 12 h with the <i>Schinus terebinthifolius</i> leaf extract (B).

<p>Midgut from control larva (A) showed a single-layered epithelium (ep) comprised of digestive (dc) and regenerative cells (rc) with preserved morphology (C). L, midgut lumen; m, muscle; n, digestive cell nuclei. Midgut from treated larva (B) showed intense disorganization of the epithelial layer (ep) with several spaces between cells (*) and some hypertrophied digestive cells (dc). Tissue/cell debris (arrowhead) is seen in the midgut lumen. m, muscle; n, digestive cell nucleus; pm, peritrophic matrix. Details of columnar digestive cells for control (C) and treated (D) larvae. Structure resembling vacuoles (v) are seen in D. n, cell nucleus; N, nucleolus; B, brush border.</p

Electron micrographs of the midguts of <i>Aedes aegypti</i> L4 from control and those treated with <i>Schinus terebinthifolius</i> leaf extract at 1.0% (w/v).

<p>Mitochondria (arrowheads); microvilli (m); electron-lucent vacuoles (V); endoplasmic reticulum (ER); nucleus (n).</p

Number of different cell types in the midgut of <i>Aedes aegypti</i> L₄ from control and those incubated for 12 h with the <i>Schinus terebinthifolius</i> leaf extract (1.0%, w/v).

<p>(A) Digestive, regenerative, and enteroendocrine cells from the midgut epithelium were counted under the fluorescence microscope. (B) Number of proliferating regenerative cells or cells with nuclear DNA damage (TUNEL positive) in the midgut epithelium were determined by fluorescence microscopy. (*) indicates significant difference (p < 0.05) in comparison to the control.</p

Proliferating regenerative cells or cells with nuclear DNA damage in the midgut of <i>Aedes aegypti</i> L₄ incubated for 12 h with distilled water (control) and <i>Schinus terebinthifolius</i> leaf extract at 1.0% (w/v).

<p>(A) Nuclei of proliferating (phosphohistone H3-positive) regenerative cells (arrow) at the posterior region of the midgut. (B) Nuclei of digestive and regenerative cells positive for DNA damage/fragmentation (arrowhead).</p