Global urban environmental change drives adaptation in white clover

Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale

Cirurgia gastrointestinal no tratamento da diabete tipo 2 Gastrointestinal surgery for the treatment of type 2 diabetes

RACIONAL: Evidências científicas demonstram o controle metabólico da diabete tipo 2 obtido com diversas intervenções sobre o sistema gastrointestinal, principalmente as operações bariátricas. OBJETIVOS: Revisar os dados da literatura referentes aos efeitos da cirurgia gastrointestinal na diabete tipo 2, especialmente os relacionados ao controle metabólico e sua fisiopatologia. MÉTODOS: Foi realizada pesquisa no Medline em páginas da internet procurando referências de artigos de maior relevância e estudos apresentados e publicados nos anais da conferência de Roma sobre os efeitos da cirurgia gastrointestinal no tratamento da diabete tipo 2 em 2007. Revisão da literatura - Entre as operações bariátricas, as derivações biliopancreáticas apresentam as mais altas taxas de controle da diabete tipo 2, seguidas pelo bypass gástrico e pela banda gástrica. Esse controle está relacionado à perda de peso e redução da ingestão de alimentos. As derivações biliopancreáticas e o bypass gástrico apresentam ainda efeito importante promovido por modificações hormonais. Os hormônios mais significativos são: o GLP-1, o GIP, o PYY, a grelina, a leptina, o IGF-1 e a adiponectina. Além dos efeitos sobre o controle do apetite no hipotálamo, os hormônios apresentam ação sobre as células &#946;, promovem a secreção de insulina e diminuem sua resistência periférica. Duas hipóteses foram formuladas para explicar as modificações desses hormônios: a do intestino anterior, em que a exclusão do duodeno e do jejuno proximal previne a secreção de algum agente ainda não identificado que promove a resistência periférica à insulina; e a do intestino posterior, em que a derivação intestinal promove a passagem rápida do quimo até o intestino distal e induz à secreção precoce dos hormônios que promovem o controle da diabete. Além das operações bariátricas tradicionais, novos procedimentos promissores foram desenvolvidos nos últimos anos. Entre eles estão o bypass duodeno-jejunal, a interposição ileal e as ressecções intestinais associadas à gastrectomia vertical. Esses novos procedimentos ainda são considerados experimentais. CONCLUSÃO: Os procedimentos cirúrgicos sobre o trato gastrointestinal, principalmente as cirurgias bariátricas, proporcionam controle metabólico da diabete tipo 2. Entre as cirurgias bariátricas os melhores resultados são obtidos com as derivações biliopancreáticas seguidas pelo bypass gástrico e pela banda gástrica. Novos procedimentos cirúrgicos, ainda considerados experimentais, estão demonstrando resultados preliminares favoráveis ao controle metabólico da diabete tipo 2.<br>BACKGROUND: The ability of gastrointestinal surgical interventions, mainly bariatric surgery, to promote the control of type 2 diabetes, has already been well documented. AIM: To review the literature related to the effects of gastrointestinal surgery regarding type 2 diabetes, especially in relation to metabolic control and its physiopathology. METHODS: Literature was reviewed on Medline, pages on the internet, references from relevant articles and studies presented and published on the annals of the International Conference on Gastrointestinal Surgery to Treat Type 2 Diabetes, which occurred in Rome in 2007. CONCLUSIONS: Among all bariatric surgeries, biliopancreatic diversion, presented the best control rates for type 2 diabetes followed by gastric bypass and gastric banding. This control is related to weight loss and reduction on food intake. Biliopancreatic diversion and gastric bypass also presented important modifications in gut hormones. The most significant ones being: GLP-1, GIP, PYY, ghrelin, leptin, IGF-1, adiponectin. These hormones promote loss of appetite, promote actions over ß cells, increase the secretion of insulin, and increase insulin sensitivity. Two theories have been formulated to explain the changes observed on these hormones: the foregut theory, where the bypass of the duodenum and proximal jejunum avoids the secretion of an unknown factor that induces insulin resistance; and the hindgut theory, where the early presentation of food to the ileum anticipates the production of hormones that control diabetes. Recently, new promising procedures have been developed. Among them are the duodenal-jejunal bypass, ileal interposition, and intestinal resection associated to vertical gastrectomy. These new procedures are still considered experimental

Global urban environmental change drives adaptation in white clover

Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale

Global urban environmental change drives adaptation in white clover

Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale

Global urban environmental change drives adaptation in white clover

Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale