Alberto Magno y la revisión de la teoría hilemórfica de Aristóteles

La doctrina hilemórfica de la materia como pura potencia y la forma como acto parece no satisfacer al dominico Alberto Magno, pues le resulta insuficiente para explicar los procesos naturales. Por esto, redefine los principios metafísicos fundamentales del aristotelismo, y asimismo expone nuevos principios constitutivos de la realidad, bajo inspiración de la filosofía neoplatónica y del pensamiento árabe. Así, Alberto sostiene que la materia prima debe ser entendida como una suerte de realidad actualizada, compuesta por diversas formas incoadas previamente al advenimiento de la forma sustancial. La incohatio formae, según el dominico, dispone a la materia a recibir cierta forma en vez de otra en la futura generación, lo cual justifica la regularidad de todo proceso natural. La materia primera, entonces, no participa meramente como sustrato del cambio sustancial y no puede ser definida como una realidad completamente simple. Por sí misma, posee un esse materiae y constituye una entidad substancial, la materia posee un ser independiente de la forma, al igual que la forma es independiente de la materia. En los tratados de la Physica y Metaphysica, Alberto Magno desarrolla una doctrina propia, aunque claramente influenciada por la cosmología y metafísica averroísta.

Vsus et exercitatio demonstrationis & ejusde[m] variae,multiplicisque formae imago .../

CCBE. S. XVIII,

Formae orandi christianae /

Edit16,

De agrorum conditionibus & constitutionibus limitum, Siculi Flacci lib. I. Iulii Frontini lib. I. Aggeni Vrbici lib. II. Hygeni Gromatici lib. II. Variorum auctorum ordines finitionum. De iugeribus metiundis. Finium regundorum. Lex Manilia. Coloniarum pop. Romani descriptio. Terminorum inscriptiones & formae. De generibus lineamentorum. De mensuris & ponderibus : Omnia figuris illustrata.

Mode of access: Internet.

Salicetum sive Salicum formae, quae bodie innotuere, descriptae et systematice dispositae.

Mode of access: Internet.

Characterization of disease resistance gene candidates of the nucleotide binding site (NBS) type from banana and correlation of a transcriptional polymorphism with resistance to Fusarium oxysporum f.sp. cubense race 4

Most plant disease resistance (R) genes encode proteins with a nucleotide binding site and leucine-rich repeat structure (NBS-LRR). In this study, degenerate primers were used to amplify genomic NBS-type sequences from wild banana (Musa acuminata ssp. malaccensis) plants resistant to the fungal pathogen Fusarium oxysporum formae specialis (f. sp.) cubense (FOC) race 4. Five different classes of NBS-type sequences were identified and designated as resistance gene candidates (RGCs). The deduced amino acid sequences of the RGCs revealed the presence of motifs characteristic of the majority of known plant NBS-LRR resistance genes. Structural and phylogenetic analyses grouped the banana RGCs within the non-TIR (homology to Toll/interleukin-1 receptors) subclass of NBS sequences. Southern hybridization showed that each banana RGC is present in low copy number. The expression of the RGCs was assessed by RT-PCR in leaf and root tissues of plants resistant or susceptible to FOC race 4. RGC1, 3 and 5 showed a constitutive expression profile in both resistant and susceptible plants whereas no expression was detected for RGC4. Interestingly, RGC2 expression was found to be associated only to FOC race 4 resistant lines. This finding could assist in the identification of a FOC race 4 resistance gene.

DNA amplification fingerprinting analysis of genetic variation within Fusarium oxysporum f.sp zingiberi

Genetic variation among 29 isolates of Fusarium oxysporum f.sp. zingiberi (Foz) collected from diseased ginger rhizome in production regions throughout Queensland was analysed using DNA amplification fingerprinting (DAF). Eight isolates of other Fusarium species and/or formae speciales were included for comparative analysis. Within the Foz isolates, three haplotypes were identified based on 17 polymorphic bands generated with five primers. Two groups showed very little genetic variation (98.6% similarity), whereas the third single isolate was quite distinct in terms of its molecular profile (77.2% similarity). Genetic similarity among the Fusarium solani, F. oxysporum f.sp. lycopersici and F. oxysporum f.sp. cubense races 1, 3 and 4 isolates compared well with the published literature.

Fusarium solani f. sp. passiflorae: A new forma specialis causing collar rot in yellow passion fruit

The aim of this study was to characterize a Fusarium population obtained from yellow passion fruit (YPF) with collar rot using pathogenicity, morphocultural characteristics and molecular tests. Pathogenicity and disease severity were assessed in six plant species: YPF, zucchini, tomato, bean, soya bean and cucumber. Potato dextrose agar medium (PDA) was used to determine mycelial growth at five temperatures (15-35°C). The colour produced by isolates was also determined on PDA at 25°C. Synthetic nutrient agar medium was used to evaluate: (i) type of mycelium and phialides; (ii) size, shape and number of septa from conidia; and (iii) production of chlamydospores and perithecia. Molecular tests consisted of sequencing the ITS-5·8S rDNA region and elongation factor 1α (EF-1α) gene. The isolates caused large lesions on YPF, zucchini and tomato, with YPF having the highest mean disease severity and being the only one that showed wilt symptoms and death of the plant. Thus the isolates showed host specificity. Maximum mycelial growth occurred at 25°C and the predominant colour was bluish-white. The isolates produced long phialides, dense aerial mycelium, oval microconidia with a mean size of 9·5 × 2·6 μm, macroconidia of 32·7 × 3·4 μm with 3·3 septa, and chlamydospores; only one isolate lacked perithecia. Phylogenetic trees of the ITS region and EF-1α gene showed that isolates from YPF formed a distinct group within the F. solani group and the formae speciales of F. solani. It is proposed to name all isolates from YPF as F. solani f. sp. passiflorae. © 2013 British Society for Plant Pathology.

A família Pinnulariaceae (Bacillariophyceae) no estado de São Paulo: levantamento florístico

Pós-graduação em Ciências Biológicas (Biologia Vegetal) - IBRC

Variabilidade genética de Fusarium spp. isolados de solos e de bananeiras com sintomas do Mal-do-Panamá

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Diversidade específica e de hábitat dos Cosmarium de parede lisa (Zygnemaphyceae) do estado de São Paulo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Observaciones sobre la belleza y su trascendentalidad en Alberto Magno

La belleza, como tema eterno de reflexión filosófica ha tenido entre los pensadores del siglo XIII un lugar particular. Ellos, desde una matriz intelectual neoplatónica, han intentado tender puentes, en algunos casos, con el aristotelismo recientemente descubierto. Este hecho parece ofrecer la posibilidad de pensar el pulchrum no sólo desde su unidad con el bonum, sino también desde su especificidad. Es aquí donde Alberto Magno ha tenido un lugar importante. Es por ello que el presente trabajo quiere ocuparse del Magno en el singular tratamiento que hace de lo bello en dos de sus obras: la Summa de Bono y el In de Divinis Nominibus. Un sucinto recorrido por estos textos permitirá advertir el esfuerzo de Alberto para perfilar un concepto de belleza que, respetando la tradición neoplatónica de su unidad con el bien, parecería encontrar su lugar propio al introducir algunos elementos pertenecientes a la filosofía del Estagirita.

Multiple avirulence paralogues in cereal powdery mildew fungi may contribute to parasite fitness and defeat of plant resistance

Powdery mildews, obligate biotrophic fungal parasites on a wide range of important crops, can be controlled by plant resistance (R) genes, but these are rapidly overcome by parasite mutants evading recognition. It is unknown how this rapid evolution occurs without apparent loss of parasite fitness. R proteins recognize avirulence (AVR) molecules from parasites in a gene-for-gene manner and trigger defense responses. We identify AVRa10 and AVRk1 of barley powdery mildew fungus, Blumeria graminis f sp hordei (Bgh), and show that they induce both cell death and naccessibility when transiently expressed in Mla10 and Mlk1 barley (Hordeum vulgare) varieties, respectively. In contrast with other reported fungal AVR genes, AVRa10 and AVRk1 encode proteins that lack secretion signal peptides and enhance infection success on susceptible host plant cells. AVRa10 and AVRk1 belong to a large family with mayor que30 paralogues in the genome of Bgh, and homologous sequences are present in other formae speciales of the fungus infecting other grasses. Our findings imply that the mildew fungus has a repertoire of AVR genes, which may function as effectors and contribute to parasite virulence. Multiple copies of related but distinct AVR effector paralogues might enable populations of Bgh to rapidly overcome host R genes while maintaining virulence.

Mitochondrial inheritance during a parasexual cycle in {\it Fusarium oxysporum\/} forma specialis {\it cubense\/}

Fusarium oxysporum is a diverse, asexual fungal species composed of both saprophytic and pathogenic members. The destructive phytopathogens are classified into formae speciales based on the host species and into vegetative compatibility groups (VCGs) based on the ability of two individuals to form heterokaryons. Parasexuality, a non-sexual mode of genetic exchange unique to some fungi has been demonstrated in the laboratory in Fusarium oxysporum f. sp. cubense (FOC). The goals of this dissertation were threefold: to ascertain whether mitochondrial (mt) markers can distinguish race differences in FOC; to determine genetic relatedness of VCGs in FOC based on a mt marker; and to discover the mode of mt inheritance during a parasexual cycle.^ Band patterns produced by electrophoresis of Hae III digested genomic DNA indicated that VCG differences, not race, could be discerned by mtDNA analysis. Primers were designed to amplify a mt intergenic locus which served as a molecular marker to screen 55 strains of FOC in 16 VCGs using both single strand conformational polymorphism and DNA sequencing. Based on homogeneity of the locus, strains were assigned to seven mitotypes, a classification unit which I introduced and found informative for grouping related VCGs.^ To determine the mode of mt inheritance during a parasexual cycle, strains in different mitotypes were paired. Mitochondrial inheritance in all hybrid progeny was found to be uniparental. I speculated that if a parasexual cycle occurs in nature there would be greater variation in the nuclear genome than the mt. This could produce multiple VCGs within a mitotype, a phenomenon observed in FOC. Based on these data, I concluded that parasexuality in nature may contribute to the diversity observed in Fusarium oxysporum. ^

Distribution of diatom species as abundance estimates from vertical multinet hauls from 150 m water depth in the Indian Ocean

During the Indian Ocean Expedition of R/V METEOR phytoplankton samples were taken with a multiple closing net (Multinet) at 103 stations. In this material the diatoms were investigated. In all 247 taxa could be identified which belong to 242 species and 5 varieties of formae of 80 genera. Of these 1 variety, 15 pecies, and 3 genera are newly described. New combinations were made for 18 species, and a number of old combinations was reinstated.