Posts Tagged ‘membrana’

Origens da Vida: Nova pesquisa sugere que o RNA não precisou de membrana para se formar

quarta-feira, outubro 10th, 2018

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Origin of life in membraneless protocells

October 9, 2018, Max Planck Society

https://phys.org/news/2018-10-life-membraneless-protocells.html

Uma nova perspectiva se abriu no tema da busca para explicar as origens da vida. O surgimento da primeira membrana sempre foi motivo de debate, pois se calculava que era necessário aparecer primeiro uma membrana para possibilitar a formação e desenvolvimento das primeiras biomoléculas, como enzimas, proteínas e RNA. Um forte candidato para solucionar o mistério são as bolhas como se vê formando na água. Mas agora um grupo de cientistas descobriram que os coacervados – uma espécie de protocélula – que não possuem membranas, podem conter em si biomoléculas de RNA e a ausência de membranas facilita a transferência de pedaços curtos da biomolécula entre indivíduos, fornecendo assim um complexo maior de informações. Mas quando focalizamos toda esta situação, ou quando lemos um artigo como esse, tendo em mente a formula da Matrix/DNA, nos vem a mente todas as soluções para as questões e se vê novos aspectos do problema. Deixarei aqui registrado o link para o artigo para retornar e destrinchar cada item citado. Enquanto isso, abaixo vai cópias de meus comentários publicado pela PHYS.ORG:

Morelli – posted at 10/10/18
Great job, but, still a scientific wrong worldview is avoiding to see the obvious here. From where Nature got the mechanism of self-replication? What else was – in the state of the world at that time and before that time – doing self-replication ? What means, which is the natural force, that produces the function of self-replication? Who drove the terrestrial atoms composing rocks, water, air, suddenly to such never seen before new connections that produced biomolecules? And why complex biomolecules?
There is a new theory with a new world view that suggests explanations for all these questions following a unique logic line: linking cosmological evolution with biological evolution we can find the picture of an evolutionary link, like a kind of non-biological DNA. The picture is at my website and it solves all these questions. Of course, while I can not show the real link, it is merely a theory. But theories are the drivers for science to find out the next missing information.

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V4Vendicar – not rated yet5 hours ago
membranes came first’
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Morelli posted 10/10/18 – not rated yetjust added

membranes came first’

Well… you are right. Before life’s origins, there were membranes in the sky, composed as membranes and working as membranes: the horizon event surrounding galactic nuclei. So, why Nature should to do the hard work of creating from nothing (applying magics?) the natural phenomena called “membrane”, if it already exists? Life which real name is “biological system” was generated here by the forces and elements existing in a planet belonging to a surrounding natural system called “solar”, which is inside other called Milk Way. It is always systems down. It is the same and unique evolutionary lineage. Of course, galaxies are our ancestors like bacteria are.So, really, membranes came first. I can’t understand why humans arbitrarily decided to separate universal evolution into two blocks without any evolutionary link between them… can you explain me? Thanks…

Read more at: https://phys.org/news/2018-10-life-membraneless-protocells.html#jCp

Membranas Vesiculares Fechadas: Nova evidência para Matrix/DNA Theory

terça-feira, janeiro 24th, 2012

O texto abaixo me fêz perceber que o aparecimento de vesiculas nas origens da Vida foi mera reprodução do “aparecimento” da aureóla de poeira estelar contendo um vórtice nas origens da galáxia. É o que chamam de “horizonte de eventos”. O tema suscita muitas questões, inclusive filosóficas e deixo-o aqui registrado para voltar quando o tempo permitir. O texto abaixo é de um post-comentário no artigo:

Can Science Define Life In Three Words?

http://www.science20.com/carl_zimmer/can_science_define_life_three_words-86052#comment-96222

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Thor Russell ..
Thor Russell | 01/21/12 | 21:49 PM

OK I can’t pass up that kind of a challenge …Firstly what do you classify as life? Presumably a prion isn’t, a cellular virus is, what about a computer virus that can modify its own code?
Its not known how life began, but a definition of life must give sensible answers to different proposed processes. One I personally find interesting (compared to the replicator starting first) is that the boundary came first “closed, membrane vesicles” as they are called.

I can’t remember the steps in detail unfortunately but lets go with what i have, and you tell me exactly when chemistry becomes life.
1. The vesicles are essentially stable bubbles, made up of a phospholipid bilayer. These can form naturally, grow naturally in the right environment divide into two because of surface tension effects I think. Now as I said I don’t think it makes sense to make a binary on/off decision about what is life, because unless it starts suddenly it makes sense to describe the steps in terms of a progression. I would not call these vesicles alive, but label them as the beginning of a potential process from which it could start.

2. Vesicles that are porous enough to let long thin molecules through are more successful than those that don’t, because those molecules clump together when inside to give structure. These vesicles out-compete the other type. Alive or not?

3. Sometimes crystal-like molecules that can grow by themselves are assimilated into the vesicle. These provide more consistent structure than just random molecules. Vesicles that let these ones through specifically are more successful than those that just let anything through. The crystals and vesicles are now dependent on each other for their successful proliferation. This is looking a lot like “independent spontaneous cooperation” now isn’t it? Surely if you insist on this definition and a binary yes/no for life then this system is now alive.

However the system described is also clearly less life-like than a complete living cell with DNA. I argue that a clear yes/no answer for what is life is not possible or desirable and that your particular definition while definitely useful and thought provoking does not always give the correct answer.

Doenças: Matriz Explicando Porque Archaea Não Causa Doenças?

quinta-feira, março 24th, 2011

A diferença que faz virus produzirem doenças e archaeas não produzirem parece estar na diferente localização das duas espécies na Matriz Astronômica, ou LUCA. Já temos mostrado vários indícios em que os vírus parecem ter vindo do trecho entre F4 e F5, ou seja, seriam aqui os representantes de pulsares e cometas, as partes masculinas de LUCA. Dois motivos são apontados para a razão de existirem virus doentíos: a) procuram a parte fêmea do circuíto, a qual está no DNA ou mitocondria das células, para se reproduzirem, mas com isso danificam a célula; b) estão no princípio da ativação da entropia. A principal diferença da archaea que lhe valeu um terceiro lugar na evolução desde o ultimo comum ancestral, ao lado dos reinos “eucariotes” e “bactérias” está na membrana externa. Tôdas as membranas são formadas por duas camadas paralelas de lípideos e basta saber que membrana é o representante do circuíto total externo para entender o porque das duas camadas: representam os dois fluxos esféricos. Mas enquanto nos outros organismos estas duas camadas podem facilmente serem separadas (como em LUCA os dois fluxos se separam), na archaea existe uma forte ponte entre as duas camadas impedindo sua separação. Ora, o trecho de LUCA onde os dois fluxos são inseparáveis é entre E1 e F3 ( saída do black hole, passagem pelo astro-baby e finalização no planeta). Isto significa que archaea está ainda antes, na evolução do que os virus. Mas explicaria porque nenhuma das quatro espécies d6estes micro-organismos não causam doenças no corpo humano, apesar de muitas habitarem o corpo humano: elas vieram do trecho de LUCA onde a energia é apenas construtiva. E também esta ligação entre as duas camadas explicaria porque a archaea difere de bactéria e eucariotes no sentido que possuem enzimas para operar nas duas faces das moléculas, a left-handed e a right-handed: apesar de, como todos os seres vivos, representar apenas a parte esquerda de LUCA, nela são expressadas com igual intensidade os dois fluxos, que compreendem a totalidade da face de LUCA.

Veja figura a seguir:

Archaea membrana

Membrane structures. Top, an archaeal phospholipid: 1, isoprene chains; 2, ether linkages; 3, L-glycerol moiety; 4, phosphate group. Middle, a bacterial or eukaryotic phospholipid: 5, fatty acid chains; 6, ester linkages; 7, D-glycerol moiety; 8, phosphate group. Bottom: 9, lipid bilayer of bacteria and eukaryotes; 10, lipid monolayer of some archaea

E para prosseguir esta tese, deixemos já registrado o que a Wikipedia fala sôbre a membrana da archaea:

Membranes

Archaeal membranes are made of molecules that differ strongly from those in other life forms, showing that archaea are related only distantly to bacteria and eukaryotes. In all organisms cell membranes are made of molecules known as phospholipids. These molecules possess both a polar part that dissolves in water (the phosphate “head”), and a “greasy” non-polar part that does not (the lipid tail). These dissimilar parts are connected by a glycerol moiety. In water, phospholipids cluster, with the heads facing the water and the tails facing away from it. The major structure in cell membranes is a double layer of these phospholipids, which is called a lipid bilayer.

These phospholipids are unusual in four ways:

Bacteria and eukaryotes have membranes composed mainly of glycerol-ester lipids, whereas archaea have membranes composed of glycerol-ether lipids. The difference is the type of bond that joins the lipids to the glycerol moiety; the two types are shown in yellow in the figure above. In ester lipids this is an ester bond, whereas in ether lipids this is an ether bond. Ether bonds are chemically more resistant than ester bonds. This stability might help archaea to survive extreme temperatures and very acidic or alkaline environments. Bacteria and eukaryotes do contain some ether lipids, but in contrast to archaea these lipids are not a major part of their membranes.
The stereochemistry of the glycerol moiety is the reverse of that found in other organisms. The glycerol moiety can occur in two forms that are mirror images of one another, called the right-handed and left-handed forms; in chemistry these are called enantiomers. Just as a right hand does not fit easily into a left-handed glove, a right-handed glycerol molecule generally cannot be used or made by enzymes adapted for the left-handed form. This suggests that archaea use entirely different enzymes for synthesizing phospholipids than do bacteria and eukaryotes. Such enzymes developed very early in life’s history, suggesting an early split from the other two domains.
Archaeal lipid tails are chemically different from other organisms. Archaeal lipids are based upon the isoprenoid sidechain and are long chains with multiple side-branches and sometimes even cyclopropane or cyclohexane rings. This is in contrast to the fatty acids found in other organisms’ membranes, which have straight chains with no branches or rings. Although isoprenoids play an important role in the biochemistry of many organisms, only the archaea use them to make phospholipids. These branched chains may help prevent archaean membranes from leaking at high temperatures.
In some archaea the lipid bilayer is replaced by a monolayer. In effect, the archaea fuse the tails of two independent phospholipid molecules into a single molecule with two polar heads; this fusion may make their membranes more rigid and better able to resist harsh environments. For example, the lipids in Ferroplasma are of this type, which is thought to aid this organism’s survival in its highly acidic habitat.