Cientistas revelam o mistério da resistência da peste negra no tempo

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[{"selector":"#anim-3a68fbab-c0f6-46ae-a197-c951cd19c853","keyframes":{"opacity":[0,1]},"delay":0,"duration":1500,"easing":"cubic-bezier(0.4, 0.4, 0.0, 1)","fill":"both"}] [{"selector":"#anim-59449d08-3ac4-4665-bf63-aec34e0bdd93","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.4, 0.4, 0.0, 1)","fill":"both"}] [{"selector":"#anim-dec47f90-0f31-4ccf-afb0-072ea38b785f","keyframes":{"opacity":[0,1]},"delay":0,"duration":500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-d2e1727d-7552-4a43-8770-d824cf15892a","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-5b0a286d-f031-40f6-9cde-acc80eedc90a [data-leaf-element=\"true\"]","keyframes":{"transform":["translate3d(29.484339994729996%, 0, 0)","translate3d(0%, 0, 0)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] Um estudo solucionou o mistério do motivo que fez a bactéria Yersinia pestis , causadora da peste-negra , sobreviver tantos séculos até a atualidade. A resposta está em uma pequena alteração genética que fez o microorganismo ser menos fatal e mais transmissível CDC/ Courtesy of Larry Stauffer, Oregon State Public Health Laboratory

[{"selector":"#anim-5d369db4-4175-4ea5-9f2a-8d28a829337f","keyframes":{"opacity":[0,1]},"delay":0,"duration":1500,"easing":"cubic-bezier(0.4, 0.4, 0.0, 1)","fill":"both"}] [{"selector":"#anim-618a7711-2fb4-486b-9106-dad2541300e9","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.4, 0.4, 0.0, 1)","fill":"both"}] [{"selector":"#anim-45ea536d-4daa-43ac-bac4-e6859d9b37d8","keyframes":{"opacity":[0,1]},"delay":0,"duration":500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-18c94d57-f008-4f1f-9b48-9c4b9e25d98a","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-76bdac4c-3c07-490d-89ba-69540ff8f77c [data-leaf-element=\"true\"]","keyframes":{"transform":["translate3d(-29.04687487285725%, 0, 0)","translate3d(0%, 0, 0)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] A ciência já sabia que algumas cepas de Y. pestis eram menos agressivas, mas o novo estudo, publicado na revista Nature, trouxe a explicação para essa variação CDC/S. Tzortzis

[{"selector":"#anim-6cba4d9d-0b09-43f9-bebf-dc9e98fe29d0","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-c044cb1c-6a2d-47ea-827b-8e186d8b2fdd","keyframes":{"transform":["translate3d(0px, 249.07409%, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-a255b801-2c55-4f6f-802b-5367e2d28348","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-a5dffd23-2c11-49d8-85b7-b65e80c56213","keyframes":{"transform":["translate3d(0px, 274.963%, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] Nossas descobertas neste estudo caracterizam um caso em que um patógeno causador de pandemia evoluiu independentemente para causar o que acreditamos ser uma forma ligeiramente mais branda da doença Ravneet Sidhu, paleogeneticista da Universidade McMaster em Hamilton

[{"selector":"#anim-f43c5fc4-8b78-4638-9380-717d1d72de21","keyframes":{"opacity":[0,1]},"delay":0,"duration":1500,"easing":"cubic-bezier(0.4, 0.4, 0.0, 1)","fill":"both"}] [{"selector":"#anim-e7993fed-a783-4f91-8ccb-9aed8400b083","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.4, 0.4, 0.0, 1)","fill":"both"}] [{"selector":"#anim-761267e3-2069-43be-ba58-13d43ce59ed2","keyframes":{"opacity":[0,1]},"delay":0,"duration":500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-d41bfcde-8bdb-4b4a-a989-c383772cb40e","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-a3fe5431-51ba-4dd0-a95b-70ad939ebdac [data-leaf-element=\"true\"]","keyframes":{"transform":["translate3d(-39.68968247254961%, 0, 0)","translate3d(0%, 0, 0)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] Para chegar a esse resultado, os pesquisadores infectaram camundongos com níveis diferentes de Pla, um gene associado à agressividade da bactéria. Os animais que receberam a cepa com Pla reduzido viveram dois dias a mais do que os que receberam a cepa normal Pixabay

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[{"selector":"#anim-946fab9b-f44c-48e1-be12-015240598fac","keyframes":{"opacity":[0,1]},"delay":0,"duration":1500,"easing":"cubic-bezier(0.4, 0.4, 0.0, 1)","fill":"both"}] [{"selector":"#anim-1acd9a69-ad65-4829-bd43-cf083e3229e1","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.4, 0.4, 0.0, 1)","fill":"both"}] [{"selector":"#anim-60e747ca-12be-4828-9cd4-d60c3bde4981","keyframes":{"opacity":[0,1]},"delay":0,"duration":500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-9dc020c7-e4f0-477f-a227-bbb6787c57fa","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] As duas cepas, no entanto, foram igualmente fatais quando infectadas por via intravenosa ou nasal, simulando infecções sanguíneas e pulmonares Freepick

[{"selector":"#anim-ce55baa8-9839-4493-8fcc-eb740caf835e","keyframes":{"opacity":[0,1]},"delay":0,"duration":1500,"easing":"cubic-bezier(0.4, 0.4, 0.0, 1)","fill":"both"}] [{"selector":"#anim-f3b7025a-555c-4a95-83eb-a5940a5a1bb5","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.4, 0.4, 0.0, 1)","fill":"both"}] [{"selector":"#anim-8c38e360-0d23-4d37-9b00-c0274b31ab3c","keyframes":{"opacity":[0,1]},"delay":0,"duration":500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-5b583b36-2bcf-4077-a52f-aa975b5853d7","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-7603e9ee-46c9-4a19-98c1-b5948836a53b [data-leaf-element=\"true\"]","keyframes":{"transform":["translate3d(0, -4.601315418876627%, 0)","translate3d(0, 0%, 0)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] O estudo explica ainda que é vantajoso para a bactéria que ela seja menos letal, já que assim ela pode viver mais tempo dentro do hospedeiro e ser transmitida mais vezes António Plácido da Costa/FMUP/Wikimedia Commons

CNNBRASIL.COM.BR

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