Size Doesn't Matter: Towards a More Inclusive Philosophy of Biology

notes: As the primary author, O’Malley drafted the paper, and gathered and analysed data (scientific papers and talks). Conceptual analysis was conducted by both authors.publication-status: Publishedtypes: ArticlePhilosophers of biology, along with everyone else, generally perceive life to fall into two broad categories, the microbes and macrobes, and then pay most of their attention to the latter. ‘Macrobe’ is the word we propose for larger life forms, and we use it as part of an argument for microbial equality. We suggest that taking more notice of microbes – the dominant life form on the planet, both now and throughout evolutionary history – will transform some of the philosophy of biology’s standard ideas on ontology, evolution, taxonomy and biodiversity. We set out a number of recent developments in microbiology – including biofilm formation, chemotaxis, quorum sensing and gene transfer – that highlight microbial capacities for cooperation and communication and break down conventional thinking that microbes are solely or primarily single-celled organisms. These insights also bring new perspectives to the levels of selection debate, as well as to discussions of the evolution and nature of multicellularity, and to neo-Darwinian understandings of evolutionary mechanisms. We show how these revisions lead to further complications for microbial classification and the philosophies of systematics and biodiversity. Incorporating microbial insights into the philosophy of biology will challenge many of its assumptions, but also give greater scope and depth to its investigations

Adição de bentonita sódica como adsorvente de aflatoxinas em rações de frangos de corte Utilization of sodium bentonite as adsorbent of aflatoxins in broiler feed

A presença de micotoxinas nas matérias-primas, principalmente no milho utilizado para rações para aves, é uma das maiores preocupações atuais devido aos danos causados por essa substâmcia não só aos animais, mas também aos produtores e às empresas do setor avícola. Considerando a utilização de adsorvente ou seqüestrante na ração para minimizar os efeitos deletérios, realizou-se um experimento para avaliar o efeito da adição de um adsorvente, baseado em bentonita sódica, na ração de frangos de corte, a fim de reduzir os efeitos de aflatoxinas. Foram utilizados 960 pintos Cobb de um dia de idade, distribuídos em oito repetições de 20 animais nos tratamentos: T1=sem aflatoxina;T2=3mg kg-1 de aflatoxina;T3=sem aflatoxina+0,5% de bentonita; T4=3mg kg-1 de aflatoxina+0,1% de bentonita; T5=3mg kg-1 de aflatoxina+0,3% de bentonita e T6=3mg kg-1 de aflatoxina+0,5% de bentonita. O consumo alimentar, o peso corporal e a conversão alimentar foram afetados pela presença da toxina na ração. A adição de bentonita sódica na ração sem aflatoxina não causou nenhum efeito depressivo nas aves. Nos tratamentos que continham 3mg kg-1 de aflatoxinas, a adição do adsorvente promoveu um melhor desempenho das aves, sendo que 0,3% de adição de bentonita apresentou melhores resultados.<br>High concentrations of micotoxins in raw materials, mainly in corn used in poultry rations of food, is an important subject of study due to hazardous problems not only to the animals themselves but also to the producer and to the poultry industry due to the reduction of performance by aflatoxins. Taking into account the lack of efficient tecnique for its elimination, from the feed, an adsorbent was added to the diets in order to reduce the effects of aflatoxins. Nine hundred sixty day old Cobb chicks, distributed in 8 replicates of 20 birds per pen the following treatments: T1=No aflatoxin; T2=3mg kg-1 of aflatoxin; T3=no aflatoxin+0.5% of bentonite; T4=3mg kg-1 of aflatoxin+0,1% of bentonite;T5=3mg kg-1 of aflatoxin+0.3% bentonite and T6=3mg kg-1 aflatoxin+ 0.5% of bentonite. Feed intake, body weight and feed conversion were depressed by aflatoxin in the feed. The addition of bentonite to the feed without aflatoxin did not caused negative effecs to the broilers. In treatments carried out with 3mg kg-1 of aflatoxins, the addition of the adsorbent promoted a better performance of the broilers with best results for those receiving 0.3% of bentonite

Sum1, a Component of the Fission Yeast eIF3 Translation Initiation Complex, Is Rapidly Relocalized During Environmental Stress and Interacts with Components of the 26S Proteasome

Eukaryotic translation initiation factor 3 (eIF3) is a multisubunit complex that plays a central role in translation initiation. We show that fission yeast Sum1, which is structurally related to known eIF3 subunits in other species, is essential for translation initiation, whereas its overexpression results in reduced global translation. Sum1 is associated with the 40S ribosome and interacts stably with Int6, an eIF3 component, in vivo, suggesting that Sum1 is a component of the eIF3 complex. Sum1 is cytoplasmic under normal growth conditions. Surprisingly, Sum1 is rapidly relocalized to cytoplasmic foci after osmotic and thermal stress. Int6 and p116, another putative eIF3 subunit, behave similarly, suggesting that eIF3 is a dynamic complex. These cytoplasmic foci, which additionally comprise eIF4E and RNA components, may function as translation centers during environmental stress. After heat shock, Sum1 additionally colocalizes stably with the 26S proteasome at the nuclear periphery. The relationship between Sum1 and the 26S proteasome was further investigated, and we find cytoplasmic Sum1 localization to be dependent on the 26S proteasome. Furthermore, Sum1 interacts with the Mts2 and Mts4 components of the 26S proteasome. These data indicate a functional link between components of the structurally related eIF3 translation initiation and 26S proteasome complexes

Distribution and Evolution of von Willebrand/Integrin A Domains: Widely Dispersed Domains with Roles in Cell Adhesion and Elsewhere

The von Willebrand A (VWA) domain is a well-studied domain involved in cell adhesion, in extracellular matrix proteins, and in integrin receptors. A number of human diseases arise from mutations in VWA domains. We have analyzed the phylogenetic distribution of this domain and the relationships among ∼500 proteins containing this domain. Although the majority of VWA-containing proteins are extracellular, the most ancient ones, present in all eukaryotes, are all intracellular proteins involved in functions such as transcription, DNA repair, ribosomal and membrane transport, and the proteasome. A common feature seems to be involvement in multiprotein complexes. Subsequent evolution involved deployment of VWA domains by Metazoa in extracellular proteins involved in cell adhesion such as integrin β subunits (all Metazoa). Nematodes and chordates separately expanded their complements of extracellular matrix proteins containing VWA domains, whereas plants expanded their intracellular complement. Chordates developed VWA-containing integrin α subunits, collagens, and other extracellular matrix proteins (e.g., matrilins, cochlin/vitrin, and von Willebrand factor). Consideration of the known properties of VWA domains in integrins and extracellular matrix proteins allows insights into their involvement in protein–protein interactions and the roles of bound divalent cations and conformational changes. These allow inferences about similar functions in novel situations such as protease regulators (e.g., complement factors and trypsin inhibitors) and intracellular proteins (e.g., helicases, chelatases, and copines)

Phototropism: Mechanism and Outcomes

Plants have evolved a wide variety of responses that allow them to adapt to the variable environmental conditions in which they find themselves growing. One such response is the phototropic response - the bending of a plant organ toward (stems and leaves) or away from (roots) a directional blue light source. Phototropism is one of several photoresponses of plants that afford mechanisms to alter their growth and development to changes in light intensity, quality and direction. Over recent decades much has been learned about the genetic, molecular and cell biological components involved in sensing and responding to phototropic stimuli. Many of these advances have been made through the utilization of Arabidopsis as a model for phototropic studies. Here we discuss such advances, as well as studies in other plant species where appropriate to the discussion of work in Arabidopsis