Biased-corrected richness estimates for the Amazonian tree flora

Amazonian forests are extraordinarily diverse, but the estimated species richness is very much debated. Here, we apply an ensemble of parametric estimators and a novel technique that includes conspecific spatial aggregation to an extended database of forest plots with up-to-date taxonomy. We show that the species abundance distribution of Amazonia is best approximated by a logseries with aggregated individuals, where aggregation increases with rarity. By averaging several methods to estimate total richness, we confirm that over 15,000 tree species are expected to occur in Amazonia. We also show that using ten times the number of plots would result in an increase to just ~50% of those 15,000 estimated species. To get a more complete sample of all tree species, rigorous field campaigns may be needed but the number of trees in Amazonia will remain an estimate for years to come

Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

This is the final version. Available on open access from Wiley via the DOI in this recordData availability statement: The percentages of dispersal modes per plot are included as Supporting Information (Table S7, based on 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests in Amazonia). The dispersal modes assigned to these 5433 species and morphospecies are also included as Supporting Information (Table S8).Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types.Colombian institution Departamento Administrativo de Ciencia, Tecnología e Innovación COLCIENCIASFaculty of Sciences, Universidad de los Ande

Produtos da glicação avançada dietéticos e as complicações crônicas do diabetes Dietetics advanced glycation end-products and chronic complications of diabetes

A geração dos produtos de glicação avançada é um dos principais mecanismos desencadeadores das doenças associadas ao diabetes mellitus, que incluem cardiopatia, retinopatia, neuropatia e nefropatia. Esta revisão tem como objetivo analisar o papel dos produtos de glicação avançada presentes na alimentação como mediadores das complicações diabéticas e apresentar estratégias de redução de sua ingestão. Para tanto, foram realizados levantamentos em bancos de dados de publicações da área, dos últimos 15 anos, considerando-se artigos de revisão, estudos clínicos e experimentais. Os produtos de glicação avançada são um grupo heterogêneo de moléculas formadas a partir de reações não enzimáticas entre grupamentos amino e carbonilo, sendo a carboximetilisina e a pentosidina exemplos de produtos de glicação avançada identificados em alimentos e in vivo. Os produtos de glicação avançada ingeridos são absorvidos, somando-se aos endógenos no surgimento e na progressão das diversas complicações do diabetes, existindo uma correlação direta entre o consumo e a concentração sanguínea. Sua restrição na alimentação se correlaciona à supressão dos níveis séricos de marcadores de doença vascular e de mediadores inflamatórios diretamente envolvidos no desenvolvimento das degenerações diabéticas. As atuais orientações dietéticas centram-se na proporção em nutrientes e na restrição energética, sem considerar o risco da ingestão de produtos de glicação avançada formados durante o processamento dos alimentos. Recomendações simples, como a utilização de temperaturas baixas por períodos mais curtos, em presença de água, no preparo de alimentos, exercem efeitos importantes na prevenção das complicações do diabetes. O estudo dos mecanismos envolvidos na geração de produtos de glicação avançada e das propriedades anti-glicação de compostos presentes nos alimentos podem contribuir com a conduta terapêutica, concorrendo para a melhoria da qualidade de vida dos portadores dessa enfermidade.<br>The generation of advanced glycation end products is one of the principal mechanisms that lead to the pathologies associated with diabetes mellitus, which include cardiopathy, retinopathy, neuropathy and nephropathy. The objective of this revision is to analyse the role of the advanced glycation end products present in food as intermediaries of diabetic complications, presenting strategies to reduce their ingestion. For this purpose, research was carried out in databases of publications of the area, for the last 15 years, taking into account revision, experimental and clinical studies. Advanced glycation end products are a heterogenous group of molecules coming from non-enzymatic reactions between amino and carbonyl groups, examples being carboxymethyllisine and pentosidine found in food and in vivo. The advanced glycation end products ingested are absorbed and, along with endogenous advanced glycation end-products, promote the progression of the complications of diabetes. There is a direct correlation between advanced glycation end products consumption and blood concentration. Their restriction in food results in the suppression of serum levels of the markers of vascular disease and the intermediaries of inflammation directly involved in the development of diabetic degenerations. The current dietary orientations are concentrated on the proportion of nutrients and on energetic restriction. The risk of ingestion of advanced glycation end products formed during the processing of food should be taken in consideration. It is simply recommended that in the preparation of food, the use of low temperatures for short periods, in the presence of water, has important effects in the prevention of the complications of diabetes. The study of the mechanisms involved in the generation of advanced glycation end products and the antiglycation properties of compounds presented in foods can contribute to a therapeutic practice and an improvement in the quality of life of people with this disease