Primera cita de Podosphaera fusca, responsable del oídio de la caléndula en Mendoza, Argentina

La caléndula (Calendula officinalis) es una planta herbácea utilizada por sus hermosas flores amarillas o naranjas en borduras, jardinería y como flor de corte. Está ampliamente difundida en el mundo, no sólo por la belleza de sus flores o por su uso en la cosmética sino por ser resistente, de fácil cultivo y poco exigente en condiciones ambientales. En Mendoza es muy empleada como ornamental y todos los años es afectada por una enfermedad denominada oídio. En Argentina se mencionan como agentes etiológicos del oídio diversas especies del género Erysiphe y Oidium erysiphoides, pero no se había descripto la forma teleomórfica sino hasta 1991 en Corrientes y Córdoba, cuando fue citada como Sphaerotheca fusca. En 2004, en Mendoza, se produjo un intenso ataque de oídio sobre esta especie floral y al estudiar la pulverulencia típica de la enfermedad se observaron cuerpos negros, lo que motivó el estudio etiológico de la enfermedad en dicha provincia. Se muestrearon ejemplares de caléndula afectados procedentes de distintos orígenes. En laboratorio se realizaron observaciones y estudios morfométricos que permitieron reconocer Podosphaera fusca (=Sphaerotheca fusca) como agente responsable del oídio de la caléndula en Mendoza.

Sarna del manzano : detección de la forma sexual (Venturia inaequalis ) en Mendoza (Argentina)

El aumento de los daños provocados por la sarna del manzano [Fusicladium dendritichum (Wallr.) Fuckl.] en montes frutales de Mendoza (Argentina), motivó estudios para aclarar la biología del hongo y buscar la presencia de la forma sexual, no detectada aún en la provincia. Al momento de la brotación se muestrearon hojas del año anterior que se encontraban en el suelo de dichos montes. En el laboratorio fueron observadas bajo estereomicroscopio. Los cuerpos negros inmersos en el tejido de la hoja fueron montados en preparados microscópicos y observados para establecer su identidad. Se confirmó la presencia en la zona de la forma teleomórfica del agente causal de la sarna del manzano. Este hecho tiene importancia en la epidemiología de la enfermedad y en las estrategias de control.

Composition of hydrothermal manganese oxide deposits from Galapagos mounds, DSDP Leg 70, Hole 509B

During DSDP Leg 70, a 1.60 m thick manganese oxide layer was sampled in hole 509B. This deposit is formed of alternating layers of hard plates of pure todorokite, about 2 mm thick, and of a more powdery material deeply impregnated with manganese oxide, about 3 mm thick. A SEM study of the plates and the associated powder shows that the powdery material is a transformation of a pre-existing sediment, while the plates are a direct precipitation from a hydrothermal solution. The uranium series disequilibrium method was used to determine the ages of the plates. They are found to be in good chronological sequence and in accordance with the sedimentation rate of the area (4.9 cm/10^3 years) which implies that they have been formed at the sediment-seawater interface during a pulsed injection of hydrothermal solution. The powder presents systematically an "older age" which is explained by a slowing down of the injection while the normal sediment settles; the older age is due to the 230Th excess of the sediment.

Palynology of marine sediment cores from the West African coast

Seven sediment cores from the cruises of the "Meteor" and "Valdivia" were examined palynologically. The cores were retrieved from the lower continental slope in the area of between 33.5° N and 8° N, off the West African coast. Most of the cores contain sediments from the last Glacial and Interglacial period. In some cases, the Holocene sediments are missing. Some individual cores contain sediments also from earlier Glacial and Interglacial periods. The main reason for making this palynological study was to find out the differences between the vegetation of Glacial and Interglacial periods in those parts of West Africa which at present belong to the Mediterranean zone, the Sahara and the zones of the savannas and tropical forests. In today's Mediterranean vegetation zone at core 33.5° N, forests and deciduous forests in particular, are missing during Glacial conditions. Semi-deserts are found instead of these. In the early isotope stage 1, there is a very significant development of forests which contain evergreen oaks; this is the Mediterranean type of vegestation development. The Sahara type of vegetation development is shown in four cores from between 27° N and 19° N. The differences between Glacial and Interglacial periods are very small. It must be assumed therefore that in this latitudes, both Glacial and Interglacial conditions gave rise to desert generally. The results are in favour of a slightly more arid climate during Glacial and more humid one during Interglacial periods. The southern boundary of the Sahara and the adjacent savannas with grassland and tropical woods were situated more to the south during the Glacial periods than they were during the Interglacial ones. In front of today's savanna belt, it can be seen from the palynological results that there are considerable differences between the vegetation of Glacial and Interglacial periods. The woods are more important in Interglacial periods. During the Glacial periods these are replaced from north to south decreasingly by grassland (savanna and rainforest type of vegetation development). The southern limit of the Sahara during stage 2 was somewhat between 12° N and 8° N which is between 1.5 and 5 degrees in latitude further south than it i s today. Not only do these differences in climate and vegetation apply to the maximum of the last Glacial and for the Holocene, but they apparently apply also to the older Glacial and Interglacial periods, where they have been found in the profiles. The North African deset belt can be said to have expanded during Glacial times both towards the north and towards the south. All the available evidence of this study indicates that the grass land or the semi-desert of the Southern Europe cam einto connection with those of the N Africa; there could not have been any forest zone between them. The present study was also a good opportunity for investigating some of the basic marine palynological problems. The very well known overrepresentation of pollen grains of the genus Pinus in marine sediments can be traced as fa as 21° N. The present southern limit for the genus Pinus is on the Canaries and on the African continent as approximately 31° N. Highest values of Ephedra pollen grains even occur south of the main area of the present distribution of that genus. These does not seem to be any satisfactory explanation for this. In general, it would appear that the transport of pollen grains from the north is more important than transport from the south. The results so far, indicate strongly that further palynological studies are necessary. These should concentrate particularly on cores from between 33° N and 27° N as well as between 17° N and 10° N. It would also be useful to have a more detailed examination of sediments from the last Intergalcial period (substage 5 e). Absolute pollen counts and more general examination of surface samples would be desirable. Surface samples should be taken from the shelf down to the bottom of the continental slope in different latitudes.

Explosion risk in coke, coal and sulphur storage

The self-ignition of all kind of powdery substances is a topic studied over the years, especially if the dusty substance is coal or substances related with coal because it may be a cause of energetic materials and human losses. But it is important to note that this is not the only risk in industrial plants that generate or store solid substances. Every combustible powders are potentially explosive and they may cause serious consequences if all the necessary factors are developed. Due to this potentially risk, it is essential a good characterization and knowledge of all the parameters involved in those processes.

Signwalling: signals derived from arabiopsis cell wall activate specific resistance to pathogens

The cell wall is a dynamic structure that regulates both constitutive and inducible plant defence responses. Different molecules o DAMPs (damage-associated molecular patterns) can be released from plant cell walls upon pathogen infection or wounding and can trigger immune responses. To further characterize the function of cell wall on the regulation of these immune responses, we have performed a biased resistance screening of putative/well-characterized primary/secondary Arabidopsis thaliana cell wall mutants (cwm). In this screening we have identified more than 20 cwm mutants with altered susceptibility/resistance to at least one of the following pathogens: the necrotrophic fungi Plectosphaerella cucumerina, the vascular bacterium Ralstonia solanacearum, the biotrophic oomycete Hyaloperonospora arabidopsidis and the powdery mildew fungus Erisyphe cruciferarum. We found that cell wall extracts from some of these cwm plants contain novel DAMPs that activate immune responses and conferred enhanced resistance to particular pathogens when they were applied to wild-type plants. Using glycomic profiling we have performed an initial characterization of the active carbohydrate structures present in these cwm wall fractions, and we have determined the signalling pathways regulated by thesse fractions. . The data generated with this collection of wall mutants support the existence of specific correlations between cell wall structure/composition, resistance to particular type of pathogens and plant fitness. Remarkably, we have identified specific cwm mutations that uncoupled resistance to pathogens from plant trade-offs, further indicating the plasticity of wall structures in the regulation of plant immune responses.

Isolation of a superfamily of candidate disease-resistance genes in soybean based on a conserved nucleotide-binding site.

The tobacco N and Arabidopsis RPS2 genes, among several recently cloned disease-resistance genes, share highly conserved structure, a nucleotide-binding site (NBS). Using degenerate oligonucleotide primers for the NBS region of N and RPS2, we have amplified and cloned the NBS sequences from soybean. Each of these PCR-derived NBS clones detected low-or moderate-copy soybean DNA sequences and belongs to 1 of 11 different classes. Sequence analysis showed that all PCR clones encode three motifs (P-loop, kinase-2, and kinase-3a) of NBS nearly identical to those in N and RPS2. The intervening region between P-loop and kinase-3a of the 11 classes has high (26% average) amino acid sequence similarity to the N gene although not as high (19% average) to RPS2. These 11 classes represent a superfamily of NBS-containing soybean genes that are homologous to N and RPS2. Each class or subfamily was assessed for its positional association with known soybean disease-resistance genes through near-isogenic line assays, followed by linkage analysis in F2 populations using restriction fragment length polymorphisms. Five of the 11 subfamilies have thus far been mapped to the vicinity of known soybean genes for resistance to potyviruses (Rsv1 and Rpv), Phytophthora root rot (Rps1, Rps2, and Rps3), and powdery mildew (rmd). The conserved N- or RPS2-homologous NBS sequences and their positional associations with mapped soybean-resistance genes suggest that a number of the soybean disease-resistance genes may belong to this superfamily. The candidate subfamilies of NBS-containing genes identified by genetic mapping should greatly facilitate the molecular cloning of disease-resistance genes.

Propagation of an attenuated virus by design: engineering a novel receptor for a noninfectious foot-and-mouth disease virus.

To gain entry into cells, viruses utilize a variety of different cell-surface molecules. Foot-and-mouth disease virus (FMDV) binds to cell-surface integrin molecules via an arginine-glycine-aspartic acid (RGD) sequence in capsid protein VP1. Binding to this particular cell-surface molecule influences FMDV tropism, and virus/receptor interactions appear to be responsible, in part, for selection of antigenic variants. To study early events of virus-cell interaction, we engineered an alternative and novel receptor for FMDV. Specifically, we generated a new receptor by fusing a virus-binding, single-chain antibody (scAb) to intracellular adhesion molecule 1 (ICAM1). Cells that are normally not susceptible to FMDV infection became susceptible after being transfected with DNA encoding the scAb/ICAM1 protein. An escape mutant (B2PD.3), derived with the mAb used to generate the genetically engineered receptor, was restricted for growth on the scAb/ICAM1 cells, but a variant of B2PD.3 selected by propagation on scAb/ICAM1 cells grew well on these cells. This variant partially regained wild-type sequence in the epitope recognized by the mAb and also regained the ability to be neutralize by the mAb. Moreover, RGD-deleted virions that are noninfectious in animals and other cell types grew to high titers and were able to form plaques on scAb/ ICAM1 cells. These studies demonstrate the first production of a totally synthetic cell-surface receptor for a virus. This novel approach will be useful for studying virus reception and for the development of safer vaccines against viral pathogens of animals and humans.

[Pamphlets on viticulture] /

[Cont.] The grape leaf-hopper (Bulletin no.198), by H. J. Quayle, 1908 -- Selection from Imperial Valley settlers' crop manual (pp.193-212) (Bulletin no.210), 1911?

Identity and pathogenicity of Fusarium spp. Isolated from wheat fields in Queensland and northern New South Wales

To establish the identity of Fusarium species associated with head blight (FHB) and crown rot (CR) of wheat, samples were collected from wheat paddocks with different cropping history in southern Queensland and northern New South Wales during 2001. CR was more widespread but FHB was only evident in northern NSW and often occurred with CR in the same paddock. Twenty different Fusarium spp. were identified from monoconidial isolates originating from different plant parts by using morphology and species-specific PCR assays. Fusarium pseudograminearum constituted 48% of all isolates and was more frequently obtained from the crown, whereas Fusarium graminearum made up 28% of all isolates and came mostly from the head. All 17 Fusarium species tested caused FHB and all 10 tested caused CR in plant infection assays, with significant (P < 0.001) difference in aggressiveness among species and among isolates within species for both diseases. Overall, isolates from stubble and crown were more aggressive for CR, whereas isolates from the flag leaf node were more aggressive for FHB. Isolates that were highly aggressive in causing CR were those originating from paddocks with wheat following wheat, whereas those from fields with wheat following maize or sorghum were highly aggressive for FHB. Although 20% of isolates caused severe to highly severe FHB and CR, there was no significant (P < 0.32) correlation between aggressiveness for FHB and CR. Given the ability of F. graminearum to colonise crowns in the field and to cause severe CR in bioassays, it is unclear why this pathogen is not more widely distributed in Australia.

Genetic diversity of Australian Fusarium graminearum and F-pseudograminearum

Genotypic diversity in Fusarium pseudograminearum and F. graminearum from Australia and the relationship between diversity and pathogen aggressiveness for head blight and/or crown rot of wheat were examined. Amplified fragment length polymorphism (AFLP) analysis revealed a high level of genotypic diversity within each species. Sixty-three of the 149 AFLP loci were significantly different between the two species and 70 of 72 F. pseudograminearum and 56 of 59 F. graminearum isolates had distinct haplotypes. When head blight and crown rot severity data from a recently published work on isolates representing the entire range of aggressiveness were used, only the genotypic diversity of F. pseudograminearum was significantly associated with its aggressiveness for the two diseases. Cluster analyses clearly demonstrated the polyphyletic structures that exist in both pathogen populations. The spatial diversity within F. graminearum was high within a single field, while frequent gene flow (N-m similar to 14) and a low fixation index (G(st) = 0.03) were recorded among F. pseudograminearum isolates from the adjacent states of New South Wales and Queensland. The differences in population structure between the heterothallic F. pseudograminearum (teleomorph G. coronicola) and the homothallic F. graminearum (teleomorph G. zeae) were not as pronounced as expected given their contrasting mating systems. Neither species was panmictic or strictly clonal. This points to sexual recombination in F. pseudograminearum, suggesting that ascospores of G. coronicola may also play a role in its biology and epidemiology.

On the drug adsorption capacity of SBA-15 obtained from various detemplation protocols

The effect of the mild detemplation method, based on Fenton chemistry (with and without previous solvent extraction), and calcination was evaluated by the drug uptake capacity of SBA-15 materials. A number of characterization techniques were applied for evaluation and comparison of the materials properties such as TGA, CNH, N2 physisorption and 29Si NMR. The mild Fenton detemplation method rendered a nearly pristine SBA-15 without structural shrinkage, low residual template, improved surface area, pore volume and silanol concentration. The drug (ibuprofen) adsorption experiments were carried out by solution immersion in powdery form. The mild detemplated samples experienced an enhanced uptake that could be explained by the enhanced density of silanols (mmol/g), originated from the absence of calcination in the Fenton approaches. © 2014 Elsevier B.V.

Análise de microestrutura e de características geotécnicas de misturas de resíduo de polimento de porcelanato e solo

Brazil is a country in development, rich in natural resources. In order to grow sustainably, it is necessary to Brazil to preserve its environment, which is an expressive challenge, especially to industries, such as those producing ceramic materials. This study was developed using Porcelain Tile Polishing Residue (RPP) in blends with soil to build compacted fills. This residue is a slurry generated during the polishing process of porcelain tiles and contains powdery material from the polished tile, the abrasives used during the process and cooling water. The RPP was collected from a private company located in Conde/PB and it was mixed with a sandy-clayey soil, to build the fills. Laboratorial tests were conducted with pure soil, pure RPP and blends in proportions of 5%, 10%, 15% and 20% of RPP in addition to the dry mass of pure soil. The Chemical and Physical Characterization tests performed were: specific solid weight, grain size distribution, laser analysis of grain size distribution, Atterberg limits, X ray fluorescence, X ray diffraction, scanning electron microscopy and soil compaction,. The materials and blends were also compacted and direct shear tests and plate load tests were performed. Plate load tests were conducted using a circular plate with 30 cm diameter, on specimens of pure soil and 5% blend, compacted in a metallic box inside the Soil Mechanics Laboratory of the Federal University of Rio Grande do Norte, Brazil. Both mechanical tests performed were conducted under inundated conditions, willing to reduce the influence of soil suction. An evaluation of the results of the tests performed shows that RPP is a fine material, with grain size distribution smaller than 0,015mm, composed mainly of silica and alumina, and particles in angular shape. The soil was characterized as a clayey sand, geologically known as a lateritic soil, with high percentages of alumina and iron oxide, and particles with rounded shape. Both the Soil and the blends presented low plasticity, while the residue showed a medium plasticity. Direct shear tests showed that the addition of RPP did not cause major changes into blends’ friction angle data, however, it was possible to note that, for the proportions studied, that is a tendency of obtain lower shear stresses for higher percentages of RPP in the blends. Both pure soil and 5% mixture showed a punching disruption for the Plate load test. For this same test, the allowable stress for 5% mixture was 44% higher than the pure soil, and smaller vertical settlement results for all stresses.

Análise de microestrutura e de características geotécnicas de misturas de resíduo de polimento de porcelanato e solo

Brazil is a country in development, rich in natural resources. In order to grow sustainably, it is necessary to Brazil to preserve its environment, which is an expressive challenge, especially to industries, such as those producing ceramic materials. This study was developed using Porcelain Tile Polishing Residue (RPP) in blends with soil to build compacted fills. This residue is a slurry generated during the polishing process of porcelain tiles and contains powdery material from the polished tile, the abrasives used during the process and cooling water. The RPP was collected from a private company located in Conde/PB and it was mixed with a sandy-clayey soil, to build the fills. Laboratorial tests were conducted with pure soil, pure RPP and blends in proportions of 5%, 10%, 15% and 20% of RPP in addition to the dry mass of pure soil. The Chemical and Physical Characterization tests performed were: specific solid weight, grain size distribution, laser analysis of grain size distribution, Atterberg limits, X ray fluorescence, X ray diffraction, scanning electron microscopy and soil compaction,. The materials and blends were also compacted and direct shear tests and plate load tests were performed. Plate load tests were conducted using a circular plate with 30 cm diameter, on specimens of pure soil and 5% blend, compacted in a metallic box inside the Soil Mechanics Laboratory of the Federal University of Rio Grande do Norte, Brazil. Both mechanical tests performed were conducted under inundated conditions, willing to reduce the influence of soil suction. An evaluation of the results of the tests performed shows that RPP is a fine material, with grain size distribution smaller than 0,015mm, composed mainly of silica and alumina, and particles in angular shape. The soil was characterized as a clayey sand, geologically known as a lateritic soil, with high percentages of alumina and iron oxide, and particles with rounded shape. Both the Soil and the blends presented low plasticity, while the residue showed a medium plasticity. Direct shear tests showed that the addition of RPP did not cause major changes into blends’ friction angle data, however, it was possible to note that, for the proportions studied, that is a tendency of obtain lower shear stresses for higher percentages of RPP in the blends. Both pure soil and 5% mixture showed a punching disruption for the Plate load test. For this same test, the allowable stress for 5% mixture was 44% higher than the pure soil, and smaller vertical settlement results for all stresses.