Francisco Carrapiço

Resumo A evolução biológica é tradicionalmente considerada como um processo gradual que consiste essenci-almente na seleção natural, conduzida através de variações fenotípicas mínimas que são o resultado de mutações e recombinações genéticas para for-mar novas espécies. Este é um processo dinâmico que se desenvolve e responde não no sentido de perfeição e progresso, mas no sentido de adaptação a novas condições. No entanto, a evolução não é apenas o resultado de mutações e recombinações genéticas combinadas com a seleção natural. Envol-ve outros processos, nomeadamente associações simbióticas entre diferentes organismos, o que tem sido secundarizado ou mesmo menosprezado pela abordagem Neodarwinista. A simbiogénese, intro-duzida em 1909 pelo biólogo russo Constantin Me-reschkowsky e definida como a origem de organis-mos pela combinação ou associação de dois ou mais seres que entram em simbiose, é um mecanis-mo evolutivo que permite uma ruptura conceptual coerente em relação a ideias evolucionistas do pas-sado, mas simultaneamente constitui e constrói uma nova abordagem evolutiva da vida no nosso planeta. Neste âmbito, a simbiose é o veículo atra-vés do qual a aquisição de novos genomas e novas capacidades metabólicas e organismais ocorrem, tornando possível a construção evolutiva dos orga-nismos. Palavras-chave: Simbiogénese. Simbiose. Evolu-ção. Pós-Neodarwinismo. Abstract Biological evolution is traditionally considered as a gradual process that consists essentially of natural selection, conducted through minimal phenotypic variations that are the result of genetic mutations and recombinations to form new species. It is likewise a dynamic process that develops and responds not in the sense of perfection and progress, but in the sense of adapting to new conditions. However, evolution is not just the result of mutations and genetic recombination combined with natural selection. It involves other processes, namely symbiotic associations between different organisms, which has been secondary or even underestimated by the neo-Darwinist approach. Symbiogenesis, introduced in 1909 by the Russian biologist Constantin Mereschkowsky and defined as the origin of organisms by the combination or association of two or more beings that enter into symbiosis, is an evolutionary mechanism that allows a coherent conceptual rupture in relation to evolutionary ideas of the past, but simultaneously consists and builds a new evolutionary approach to life on our planet. In this context, symbiosis is the vehicle through which the acquisition of new genomes and new metabolic and organismal capacities occurs, making possible the evolutionary construction of organisms.

A fotossíntese é, conjuntamente com a glicólise, um dos mais antigos e importantes processos metabólicos responsáveis pela vida e no qual o armazenamento de energia ocorre nas regiões clorofilinas da planta, desenrolando-se este processo na presença da luz. A energia luminosa é armazenada sob a forma de um monossacárido (glucose) produzido a partir do dióxido de carbono presente no ar e da água absorvida pela planta. Quando o dióxido de carbono ea água se combinam para formar glucose, origina-se ...

A passagem dos vegetais do meio aquático para o meio aéreo foi acompanhada por modificações, não apenas a nível morfológico e reprodutor, como, de igual modo, a nível bioquímico. Estas novas vias bioquímicas desenvolveram-se a partir de aminoácidos aromáticos, cuja síntese é comum quer aos microorganismos, quer às plantas. No entanto, apenas alguns grupos vegetais foram capazes de desenvolver etapas bioquímicas ulteriores que, através da desaminação da fenilalanina e da tirosina, possibilitam a ...

Apesar da diversidade do mundo biológico, a linguagem química que caracteriza esse mundo é na maioria dos casos comum. Os organismos vivos são construídos por unidades ou entidades químicas, as quais podem ou não estar estruturadas sob a forma polimérica. No entanto, é sob a forma de polímeros que o seu papel é mais significativo na dinâmica da vida. Entre os polímeros que caracterizam um organismo salientam-se os polissacáridos (moléculas que armazenam energia química), as proteínas (moléculas estruturais que ...

This  work  is  a  contribution  to  the  literature  and  knowledge  on  evolution  that  takes  into  account  the  biological  data  obtained  on  symbiosis  and  symbiogenesis.  Evolution  is  traditionally  considered  a  gradual  process  essentially
consisting  of  natural  selection,  conducted  on  minimal  phenotypical  variations that  are  the  result  of  mutations  and  genetic  recombinations  to  form  new  species.  However,  the  biological  world  presents  and  involves  symbiotic  associations
between  different  organisms  to  form  consortia,  a  new structural  life  dimension  and a  symbiont-induced  speciation.  The  acknowledgment  of  this  reality  implies  a  new
understanding  of  the  natural  world,  in  which  symbiogenesis  plays  an  important role  as  an  evolutive  mechanism.  Within  this  understanding,  symbiosis  is  the  key to  the  acquisition  of  new  genomes  and  new  metabolic  capacities,  driving  living
forms’  evolution  and  the  establishment  of  biodiversity  and  complexity  on  Earth. This  chapter  provides  information  on  some  of  the  key  figures  and  their  major works  on  symbiosis  and  symbiogenesis  and  reinforces  the  importance  of  these
concepts  in  our  understanding  of  the  natural  world  and  the  role  they  play  in  the establishing  of  the  evolutionary  complexity  of  living  systems.  In  this  context,  the concept  of  the  symbiogenic  superorganism  is  also  discussed.

The development of the prokaryotic colony in Azolla filiculoides indicates that Anabaena azollae is maintained through the life cycle of the fern and present in the leaves and megasporocarps. The same biological pattern is applied to the bacteria that are also present in these structures and seems to follow a development pattern identical to the cyanobacteria and probably can be considered the third partner of this symbiotic association.

This work is a contribution to the literature and knowledge on evolution that takes into account the biological data obtained on symbiosis and symbiogenesis. Evolution is traditionally considered a gradual process essentially consisting of natural selection, conducted on minimal phenotypical variations that are the result of mutations and genetic recombinations to form new species. However, the biological world presents and involves symbiotic associations between different organisms to form consortia, a new structural life dimension and a symbiont-induced speciation. The acknowledgment of this reality implies a new understanding of the natural world, in which symbiogenesis plays an important role as an evolutive mechanism. Within this understanding, symbiosis is the key to the acquisition of new genomes and new metabolic capacities, driving living forms’ evolution and the establishment of biodiversity and complexity on Earth. This chapter provides information on some of the key figures and their major works on symbiosis and symbiogenesis and reinforces the importance of these concepts in our understanding of the natural world and the role they play in the establishing of the evolutionary complexity of living systems. In this context, the concept of the symbiogenic superorganism is also discussed.

Symbiosis is one of the main processes responsible for the biodiversity and evolution on Earth, which has had a leading role in the morphological, physiological, and metabolical complexification of organisms. Azolla, a heterosporious floating or semi-aquatic fern, constitutes a good example of a synergistic symbiotic system. In the chlorophyllous dorsal lobe leaf, there is an ellipsoid cavity with a filamentous nitrogen-fixing cyanobacterium, usually referred to as Anabaena azollae, and several genera of bacteria. This leaf cavity behaves both as the physiological and dynamic interface unit of this symbiotic association where the main metabolic and energetic flows occur, and as a natural microcosm. This symbiosis is sustained throughout the fern’s life cycle, where the cyanobacteria and bacteria are always present. In the Azolla-Anabaena-bacteria association, complex ecological communities of permanent microorganisms cooperate along with the fern in the maintenance of the whole, which leads to the idea that this symbiotic system can be considered as a superorganism in ecological terms. New metabolic and organic capabilities are acquired and developed by the partners, which establish a new level of organization that goes beyond the individual capabilities of any individual partner, suggesting that the synergies associated to symbiosis had and have a leading role in the morphology, reproduction, physiology, and metabolic complexification of the organisms.

When new entities are formed by the integration of individual organisms, these new entities possess characteristics which go beyond the sum of the individual properties of each element of the association, resulting in the development of new attributes and capacities as an integrated whole. In this process, these new entities also agglutinate and dynamize synergies not present in the individual organisms. In this sense, evolution is a dynamic process that evolves not in the way of perfection or progress, but in the way of adaptation to new conditions. Symbiogenesis, as an evolutionary mechanism, allows a coherent conceptual rupture with some evolutionary ideas of the past and, at the same time, shows and builds a new approach to life, based on solid evolutionary ideas, expanding evolution to an adequate level of integration with the more recent data in biology. These ideas and concepts should be integrated in a post-neodarwinian approach to evolution that needs further attention from the scientific community. The development of a Symbiogenic Theory of Evolution could contribute toward a new epistemological approach of the symbiotic phenomenon in the evolutionary context. This, in our point of view, could be the beginning of a new paradigm in science that rests almost unexplored.

Abstract Cell extracts from the Azolla-Anabaena system are known to cause agglutination of erythrocytes, and if lectins, which are carbohydrate-binding proteins, are involved in the establishment of the Azolla-Anabaena-bacteria symbiosis, they may play any role in it. In order to clarify this situation, we have isolated and identified six different bacterial strains contained in the leaf cavities of two Azolla species (A. filiculoides and A. pinnata). From

Abstract Cell extracts from the Azolla-Anabaena system are known to cause agglutination of erythrocytes, and if lectins, which are carbohydrate-binding proteins, are involved in the establishment of the Azolla-Anabaena-bacteria symbiosis, they may play any role in it. In order to clarify this situation, we have isolated and identified six different bacterial strains contained in the leaf cavities of two Azolla species (A. filiculoides and A. pinnata). From

Azolla filiculoides showed a planar development in four culture media, but with overlapping of sporophytes after 28 days, and curled roots in all cases except for IRRI2. The difference in biomass between the media IRRI2 and IRRI1‐Fe10x was statistically significant at Days 14, 21 and 28 by ANOVA. Medium IRRI2 gave the highest duplication time.

Family Azollaceae has seven species with a controversial taxonomy. The identification of species without reproductive structures relies on vegetative characters but some are variable, leading to misinterpretations. The molecular methods may be helpful, but until now, they did not provide a conclusive Azolla taxonomy. Therefore, we studied the family Azollaceae at vegetative and molecular levels. Analysis of vegetative, random amplified polymorphic DNA (RAPD) and combined data showed a comparable grouping of the Azolla species in two main clusters: cluster I, referred to as section Rhizosperma (A. pinnata and A. nilotica) and cluster II, referred to as section Azolla (A. filiculoides, A. microphylla, A. caroliniana and A. mexicana), with the exception of A. rubra, which clustered differently depending on the method. All the Azolla species were distinguished by the 13 polymorphic vegetative characters, the 211 RAPD markers or the combined data, with the latest showing the highest discrimination. The Shannon Index diversity was greater with RAPD (2.276) than with vegetative characters (0.054), highlighting the higher discriminating power of the molecular data. The partitioning of diversity was, as expected, high among species for all the types of data and low within species, with the lowest diversity obtained for morphological data. Both data sets (vegetative and RAPD) allowed the distinction of all the species and their clustering into sections Rhizosperma and Azolla, suggesting this as the most correct for this family. The dendrogram from the combined data was the most accurate, highlighting the benefit of integrating different types of data to study the family Azollaceae.

Abstract Azolla filiculoides is an aquatic pteridophyte that may be used as animal food, biofertilizer and phytoremediation. Its volatile composition was never studied although several phytochemical analyses were performed. The volatile composition of A. filiculoides grown outdoors in a pond at the Botanical Garden of Lisbon University (BGLU) or in culture conditions as well as the effect of different harvesting times and the storage type were evaluated.

Abstract This work analyses the environmental impact of the Azolla bloom which took place in the Guadiana river, in April 1993, namely in the Mértola region, where we describe the human population's behaviour, in particular that of professional communities, when facing this bloom. The fact that they had no previous knowledge of the phenomenon, as well as the absence of a practical management model in this kind of situation, brought about some difficulties.

Stenopelmus rufinasus Gyllenhal is a small, semiaquatic weevil which lives and feeds on floating aquatic pteridophytes of the genus Azolla Lam.(Azollaceae), and was described for the first time in Schönherr (1835). This beetle is indigenous to southern and western USA, being present also in Argentina and Paraguay as well as in Europe, where it was introduced accidentally with Azolla (Janson 1921; Richerson and Grigarick 1967; Hill 1998). In 1995, South Africa imported S.

Abstract Azolla is a free floating aquatic heterosporic pteridophyte that in some conditions becomes a weed. In previous works we have studied the causes and consequences of the first major Azolla bloom in Portugal. This occurred in the Guadiana river in April 1993. A similar phenomenon, also with an extension of several kilometers, took place in 1995, in the same river and in the same month of the year.

SUMMARY Infected roots of Ophrys lutea present nymerous peroxisome profiles identified by diaminobenzidine (DAB) staining. The presence of uricase in these peroxisomes could also be recognized cytochemically. The activities of catalase and uricase, assayed using a crude fraction of peroxisomes, reached 0· 8 μkat min− 1 protein-1 and 1· 73 nakat min− 1 mg protein− 1 respectively. The role of uricase in purine metabolism is discussed in terms of host/endophyte interactions in O. lutea mycorrhzas.

The Guadiana River is an international one that has its spring in Spain (Campo Montiel) and its mouth between Ayamonte and Vila Real de Santo Antonio (Algarve, Portugal). The basin area of the river is about 67,000 km super(2), of which 12,000 km super(2) are in Portuguese territory. In 1990-1993, southern Portugal experienced low rainfall with long dry seasons. This factor, combined with several dams along the river, caused low water flow during 1993.

Abstract (English) Azolla pinnata R. Br. subsp. africana (Desv.) AMK Saunders & K. Fowler is an aquatic floating fern that lives in the Geba River, located in the eastern region of the Republic of Guinea-Bissau (West Africa). This fern shows in this country a life cycle between August and March and has been tested, namely in the last few years, as green manure on rice culture. The aquatic macrophytes community associated with this fern is composed by eight species: Trapa natans L. var.

We live in a symbiotic world where many living forms, from the simplest
to the most complex ones, have associations with microorganisms. Thus, symbiosis plays a very important role in the origin, organization, and evolution of life. Given their role in the association, symbionts are among the key actors in this interplay. Traditionally, the symbiont is seen as a supporting actor, with a secondary role in the play, whereas the host is understood as having the leading role. However, bacteria and, more recently, viruses have gradually come to be seen as important elements of
these symbiotic relationships or consortia, and as one of the key factors in the evolution and organization of the web of life, as well as its health and disease. The gut microbiome, namely in humans, is another important case study to understand the importance of symbionts. Misunderstood and diabolized for a long time, the human gastrointestinal microbiome represents a challenge and an opportunity to understand in a holistic way how the human body works and the effects that it has on our health. This could be the beginning of a new paradigm in science, namely in
biology and medicine, that remains almost unexplored and that challenges the traditional concept of organism.