Efecto del fotoperiodo en la terminación de la diapausa de larvas de los taladros del maíz, Sesamia nonagrioides y Ostrinia nubilalis, desarrolladas en distintas variedades de maíz transgénico y sus isogénicas correspondientes

La creciente implantación de maíz transgénico en España está ocasionando cambios importantes en las poblaciones de taladros de maíz y en su ecofisiología, cambios que están por estudiar. En el evento de maíz transgénico Bt 176, hoy en día no autorizado, la concentración de proteína de Bacillus thuringiensis decrecía en el maíz senescente de forma que en otoño se podían encontrar en campos con este evento alguna larva de taladros. La implantación de maíz con el evento MON 810 sugirió la posibilidad de estudiar la posible supervivencia de larvas en maíz senescente y algunos aspectos de la diapausa de estas larvas. Para ello se infestaron 6 variedades de maíz, una con el evento Bt 176, dos con el evento MON 810 y las tres isogénicas correspondientes, con larvas neonatas de Sesamia nonagrioides (Lefébvre), confiando en una infestación natural de Ostrinia nubilalis (Hübner). Las larvas de S. nonagrioides recogidas en el evento Bt176 suponían el 14% del total de larvas de esta especie muestreadas, mientras que las de O. nubilalis recogidas en el maíz Bt suponían un 25% del total de esta especie. Sin embargo en las variedades con el evento MON 810 apenas se recogieron un 0,25% y un 1,9% de larvas de S. nonagrioides y O. nubilalis respectivamente. Las larvas recogidas en el evento Bt 176 no mostraron diferencias en su intensidad de diapausa con las recogidas en las isogénicas correspondientes. El efecto del fotoperiodo en la terminación de la diapausa fue diferente en ambas especies: mientras que el fotoperiodo largo aceleraba la terminación de diapausa en S. nonagrioides pero no en O. nubilalis pareciendo tener un efecto más pronunciado la oscuridad completa. El parasitismo por parte de Lydella thompsoni (Herting) fue del 5% para el total de larvas de O. nubilalis mientras que para el total de larvas de S. nonagrioides fue del 0,4% lo que indica la preferencia de esta taquínido por el pirálido.

Taxonomia numerica de algunas especies de Lavandula L., basada en caracteres morfologicos, cariologicos y palinologicos

Se hace un estudio sistemático de las especies y subespecies de Lavandula L. de la Península Ibérica, utilizando la taxonomía numérica y tomando en consideración 56 caracteres, 31 de los cuales son palinológicos y 25 morfológicos y cariológicos. Los resultados obtenidos justifican, a nuestro juicio, la ordenación sistemática del género y la existencia de una nueva sección que proponemos como sect. Dentada. Asimismo, consideramos que Lavandula stoechas L. subsp. pedunculata (Miller) Samp. ex Rozeira, por los caracteres palinológicos, merece la categoría de especie, reivindicando para este taxon el binomen Lavandula pedunculata Cav.

Aportacion a la cariologia del G. Lavandula L. de la Peninsula Iberica

Se dan a conocer por primera vez los números cromosomáticos de diferentes especies de Lavandula L.: L. angustifolia Miller subsp. pyrenaica (DC.) Guinea 2/1=48; L. stoechas L. subsp. lusitanica (Chaytor) Rozeira y L. stoechas L. subsp. luisieri (Rozeira) Rozeira 2n=30. Se publica para L. dentata L. 2n = 42, número que concuerda con el básico admitido para el género, x=6, y que difiere del obtenido por otros autores. Se confirman los números 2n=30 para L. stoechas L. subsp. stoechas, L. stoechas subsp. sampaiana Rozeira y L. pedunculata Cav.

Dades floristiques per a l'Alt Bergueda

Se presenta una lista de 19 táxones con interés corológico, del Alt Berguedá (Pirineos orientales), con algunas observaciones acerca de su ecología, y en algunos casos con su distribución en Cataluña. La lista incluye nuevas localidades pirenaicas para orófitos (Brassica repanda subsp. turbonis, Alyssum cuneifolium), plantas mediterráneas (Asparagus acutifolius, Arenaria modesta), sinantrópicas (Impatiens balfourii), etc.

Combinationes novae

Ranunculus Balbisii Moris subsp. Weyleri (Mares et Vig.) comb, nova ( = Ranunculus Weyleri Mares et Vigineix, Catalogue raisonne des plantes vasculaires des lies Baleares : 5, Paris 1880).

Peucedanum schottii Besser ex DC., novedad para la Flora Iberica.

En otoño de 1984 tuvimos la ocasión de recolectar este orófito europeo, con fruto maduro, en la cumbre del macizo calcáreo de la 'Mare de Deu del Mont', próximo a la población de Besalú (Prepirineos orientales). Vive en los rellanos herbosos inclinados, fisuras y oquedades de la cumbre, muy localizado, en pastos mesoxerófilos del Festucion gautieri. Un inventario tomado en el lugar muestra la siguiente composición florística (exp. N, incl. 60°, cobert. 100%): Festuca gautieri 5.5, Peucedanum schottii 2.3, Veronica austriaca subsp. vahlii 1.1, Avenula mirandana 1.1, Cruciata glabra 1.1, Phyteuma orbiculare 1.1, Seseli montanum 1.1, Dianthus seguieri subsp. gautieri 1.1, Galium pinetorum + , Vicia sepium +, Campanula rotundifolia +, Moehringia muscosa +.1, Allium senescens +, Teucrium chamaedrys + , Asperula cynanchica +, Dactylis glomerata + , Dianthus monspeliacus +, Sedum reflexum +, Vincetoxicum hirundinaria subsp. intermedium +.

Sobre la planta del genero 'Crassula' descubierta en el Baix Llobregat

En 1969 dos de nosotros (TERRADAS y VIGO) dimos cuenta en una publicación titulada 'Sobre la vegetación de la zona de acantilados del Baix Llobregat' del hallazgo en dicha región de una planta del género Crassula que resultó especie nueva para la flora de Europa. De acuerdo con las indagaciones que pudimos llevar a cabo entonces, llegamos a la conclusión de que la planta descubierta por nosotros debía considerarse como muy afín de Crassula pentandra (Royle ex Edgew) Schoenl., especie extendida por el África tropical y la India, y la describimos bajo el nombre de Crassula pentandra subsp. catalaunica. Los caracteres que separan esta planta de Crassula pentandra típica, especificados en la publicación mencionada, corresponden a diferencias cuantitativas de orden general y, más especialmente, en el menor tamaño de las piezas florales así como de los frutos y semillas

Acerca de los tipos de dos Veronica rifeñas.

Hace unos años, se publicó en esta misma sección una nota sobre Veronica rosea (Soriano, 1996), en la que se anticipaba el tratamiento de este taxón en la checklist de la fl ora del norte de Marruecos (Valdés & al. 2002; Soriano, 2002). Entre otras cosas, se formalizaba en ella la descripción de V. rosea subsp. atlantica var. macrantha, propuesta por Pau como V. rosea var. macrantha y distribuida por Font Quer en el Iter maroccanum de 1930, aunque sin la diagnosis correspondiente.

Galactofuranose in Mycoplasma mycoides is important for membrane integrity and conceals adhesins but does not contribute to serum resistance.

Mycoplasma mycoides subsp. capri (Mmc) and subsp. mycoides (Mmm) are important ruminant pathogens worldwide causing diseases such as pleuropneumonia, mastitis and septicaemia. They express galactofuranose residues on their surface, but their role in pathogenesis has not yet been determined. The M. mycoides genomes contain up to several copies of the glf gene, which encodes an enzyme catalysing the last step in the synthesis of galactofuranose. We generated a deletion of the glf gene in a strain of Mmc using genome transplantation and tandem repeat endonuclease coupled cleavage (TREC) with yeast as an intermediary host for the genome editing. As expected, the resulting YCp1.1-Δglf strain did not produce the galactofuranose-containing glycans as shown by immunoblots and immuno-electronmicroscopy employing a galactofuranose specific monoclonal antibody. The mutant lacking galactofuranose exhibited a decreased growth rate and a significantly enhanced adhesion to small ruminant cells. The mutant was also 'leaking' as revealed by a β-galactosidase-based assay employing a membrane impermeable substrate. These findings indicate that galactofuranose-containing polysaccharides conceal adhesins and are important for membrane integrity. Unexpectedly, the mutant strain showed increased serum resistance.

The lipopolysaccharide of Aeromonas spp: structure-activity relationships.

Marine microorganisms, including Aeromonas, are a source of compounds for drug development that have generated great expectations in the last decades. Aeromonas infections produce septicaemia, and ulcerative and haemorrhagic diseases in fish. Among the pathogenic factors associated with Aeromonas, the lipopolysaccharides (LPS), a surface glyconconjugate unique to Gram-negative bacteria consisting of lipid A (lipid anchor of the molecule), core oligosaccharide and O-specific polysaccharide (O antigen), are key elicitors of innate immune responses. The chemical structure of these three parts has been characterized in Aeromonas. Based on the high variability of repeated units of O-polysaccharides, a total of 97 O-serogroups have been described in Aeromonas species, of which four of them (O:11; O:16; O:18 and O:34) account for more than 60% of the septicemia cases. The core of LPS is subdivided into two regions, the inner (highly conserved) and the outer core. The inner core of Aeromonas LPS is characterized by the presence of 3-deoxy-D-manno-oct-2-ulosonic (ketodeoxyoctonic) acid (Kdo) and L-glycero-D-manno-Heptoses (L,D-Hep), which are linked to the outer core, characterized by the presence of Glc, GlcN, Gal, and GalNAc (in Aeromonas salmonicida), D,D-Hep (in Aeromonas salmonicida), and L,D-Hep (in Aeromonas hydrophila). The biological relevance of these differences in the distal part of the outer core among these species has not been fully assessed to date. The inner core is attached to the lipid A, a highly conserved structure that confers endotoxic properties to the LPS when the molecule is released in blood from lysed bacteria, thus inducing a major systemic inflammatory response known as septic or endotoxic shock. In Aeromonas salmonicida subsp. salmonicida the Lipid A components contain three major lipid A molecules, differing in acylation patterns corresponding to tetra-, penta- and hexaacylated lipid A species and comprising of 4′-monophosphorylated β-2-amino-2-deoxy-D-glucopyranose-(1→6)-2-amino-2-deoxy-D-glucopyranose disaccharide. In the present review, we discuss the structure-activity relationships of Aeromonas LPS, focusing on its role in bacterial pathogenesis and its possible applications.

Evolutionary Ecology of Mountain Birch in Subarctic Stress Gradients: Interplay of Biotic and Abiotic Factors in Plant-Plant Interactions and Evolutionary Processes

In nature, variation for example in herbivory, wind exposure, moisture and pollution impact often creates variation in physiological stress and plant productivity. This variation is seldom clear-cut, but rather results in clines of decreasing growth and productivity towards the high-stress end. These clines of unidirectionally changing stress are generally known as ‘stress gradients’. Through its effect on plant performance, stress has the capacity to fundamentally alter the ecological relationships between individuals, and through variation in survival and reproduction it also causes evolutionary change, i.e. local adaptations to stress and eventually speciation. In certain conditions local adaptations to environmental stress have been documented in a matter of just a few generations. In plant-plant interactions, intensities of both negative interactions (competition) and positive ones (facilitation) are expected to vary along stress gradients. The stress-gradient hypothesis (SGH) suggests that net facilitation will be strongest in conditions of high biotic and abiotic stress, while a more recent ‘humpback’ model predicts strongest net facilitation at intermediate levels of stress. Plant interactions on stress gradients, however, are affected by a multitude of confounding factors, making studies of facilitation-related theories challenging. Among these factors are plant ontogeny, spatial scale, and local adaptation to stress. The last of these has very rarely been included in facilitation studies, despite the potential co-occurrence of local adaptations and changes in net facilitation in stress gradients. Current theory would predict both competitive effects and facilitative responses to be weakest in populations locally adapted to withstand high abiotic stress. This thesis is based on six experiments, conducted both in greenhouses and in the field in Russia, Norway and Finland, with mountain birch (Betula pubescens subsp. czerepanovii) as the model species. The aims were to study potential local adaptations in multiple stress gradients (both natural and anthropogenic), changes in plant-plant interactions under conditions of varying stress (as predicted by SGH), potential mechanisms behind intraspecific facilitation, and factors confounding plant-plant facilitation, such as spatiotemporal, ontogenetic, and genetic differences. I found rapid evolutionary adaptations (occurring within a time-span of 60 to 70 years) towards heavy-metal resistance around two copper-nickel smelters, a phenomenon that has resulted in a trade-off of decreased performance in pristine conditions. Heavy-metal-adapted individuals had lowered nickel uptake, indicating a possible mechanism behind the detected resistance. Seedlings adapted to heavy-metal toxicity were not co-resistant to others forms of abiotic stress, but showed co-resistance to biotic stress by being consumed to a lesser extent by insect herbivores. Conversely, populations from conditions of high natural stress (wind, drought etc.) showed no local adaptations, despite much longer evolutionary time scales. Due to decreasing emissions, I was unable to test SGH in the pollution gradients. In natural stress gradients, however, plant performance was in accordance with SGH, with the strongest host-seedling facilitation found at the high-stress sites in two different stress gradients. Factors confounding this pattern included (1) plant size / ontogenetic status, with seedling-seedling interactions being competition dominated and host-seedling interactions potentially switching towards competition with seedling growth, and (2) spatial distance, with competition dominating at very short planting distances, and facilitation being strongest at a distance of circa ¼ benefactor height. I found no evidence for changes in facilitation with respect to the evolutionary histories of plant populations. Despite the support for SGH, it may be that the ‘humpback’ model is more relevant when the main stressor is resource-related, while what I studied were the effects of ‘non-resource’ stressors (i.e. heavy-metal pollution and wind). The results have potential practical applications: the utilisation of locally adapted seedlings and plant facilitation may increase the success of future restoration efforts in industrial barrens as well as in other wind-exposed sites. The findings also have implications with regard to the effects of global change in subarctic environments: the documented potential by mountain birch for rapid evolutionary change, together with the general lack of evolutionary ‘dead ends’, due to not (over)specialising to current natural conditions, increase the chances of this crucial forest-forming tree persisting even under the anticipated climate change.

The lipopolysaccharide of Aeromonas spp: structure-activity relationships

Marine microorganisms, including Aeromonas, are a source of compds. for drug development that have generated great expectations in the last decades. Aeromonas infections produce septicemia, and ulcerative and haemorrhagic diseases in fish. Among the pathogenic factors assocd. with Aeromonas, the lipopolysaccharides (LPS)​, a surface glyconconjugate unique to Gram-​neg. bacteria consisting of lipid A (lipid anchor of the mol.)​, core oligosaccharide and O-​specific polysaccharide (O antigen)​, are key elicitors of innate immune responses. The chem. structure of these three parts has been characterized in Aeromonas. Based on the high variability of repeated units of O-​polysaccharides, a total of 97 O-​serogroups have been described in Aeromonas species, of which four of them (O:11; O:16; O:18 and O:34) account for more than 60​% of the septicemia cases. The core of LPS is subdivided into two regions, the inner (highly conserved) and the outer core. The inner core of Aeromonas LPS is characterized by the presence of 3-​deoxy-​d-​manno-​oct-​2-​ulosonic (ketodeoxyoctonic) acid (Kdo) and l-​glycero-​d-​manno-​Heptoses (l,​d-​Hep)​, which are linked to the outer core, characterized by the presence of Glc, GlcN, Gal, and GalNAc (in Aeromonas salmonicida)​, d,​d-​Hep (in Aeromonas salmonicida)​, and l,​d-​Hep (in Aeromonas hydrophila)​. The biol. relevance of these differences in the distal part of the outer core among these species has not been fully assessed to date. The inner core is attached to the lipid A, a highly conserved structure that confers endotoxic properties to the LPS when the mol. is released in blood from lysed bacteria, thus inducing a major systemic inflammatory response known as septic or endotoxic shock. In Aeromonas salmonicida subsp. salmonicida the Lipid A components contain three major lipid A mols., differing in acylation patterns corresponding to tetra-​, penta- and hexa-​acylated lipid A species and comprising of 4'-​monophosphorylated β-​2-​amino-​2-​deoxy-​d-​glucopyranose-​(1→6)​-​2-​amino-​2-​deoxy-​d-​glucopyranose disaccharide. In the present review, we discuss the structure-​activity relationships of Aeromonas LPS, focusing on its role in bacterial pathogenesis and its possible applications.

The lipopolysaccharide of Aeromonas spp: structure-activity relationships

Marine microorganisms, including Aeromonas, are a source of compds. for drug development that have generated great expectations in the last decades. Aeromonas infections produce septicemia, and ulcerative and haemorrhagic diseases in fish. Among the pathogenic factors assocd. with Aeromonas, the lipopolysaccharides (LPS)​, a surface glyconconjugate unique to Gram-​neg. bacteria consisting of lipid A (lipid anchor of the mol.)​, core oligosaccharide and O-​specific polysaccharide (O antigen)​, are key elicitors of innate immune responses. The chem. structure of these three parts has been characterized in Aeromonas. Based on the high variability of repeated units of O-​polysaccharides, a total of 97 O-​serogroups have been described in Aeromonas species, of which four of them (O:11; O:16; O:18 and O:34) account for more than 60​% of the septicemia cases. The core of LPS is subdivided into two regions, the inner (highly conserved) and the outer core. The inner core of Aeromonas LPS is characterized by the presence of 3-​deoxy-​d-​manno-​oct-​2-​ulosonic (ketodeoxyoctonic) acid (Kdo) and l-​glycero-​d-​manno-​Heptoses (l,​d-​Hep)​, which are linked to the outer core, characterized by the presence of Glc, GlcN, Gal, and GalNAc (in Aeromonas salmonicida)​, d,​d-​Hep (in Aeromonas salmonicida)​, and l,​d-​Hep (in Aeromonas hydrophila)​. The biol. relevance of these differences in the distal part of the outer core among these species has not been fully assessed to date. The inner core is attached to the lipid A, a highly conserved structure that confers endotoxic properties to the LPS when the mol. is released in blood from lysed bacteria, thus inducing a major systemic inflammatory response known as septic or endotoxic shock. In Aeromonas salmonicida subsp. salmonicida the Lipid A components contain three major lipid A mols., differing in acylation patterns corresponding to tetra-​, penta- and hexa-​acylated lipid A species and comprising of 4'-​monophosphorylated β-​2-​amino-​2-​deoxy-​d-​glucopyranose-​(1→6)​-​2-​amino-​2-​deoxy-​d-​glucopyranose disaccharide. In the present review, we discuss the structure-​activity relationships of Aeromonas LPS, focusing on its role in bacterial pathogenesis and its possible applications.

Incidence of pectolytic erwinias associated with blackleg of potato in Rio Grande do Sul

Erwinia carotovora subsp. atroseptica (Eca), E. carotovora subsp. carotovora (Ecc) and E. chrysanthemi (Ech) may cause potato (Solanum tuberosum) blackleg. To determine the occurrence of these pathogens in the conditions found in the State of Rio Grande do Sul (RS), potato plants showing blackleg symptoms were harvested from 22 fields in nine counties in Serra do Nordeste, Planalto, Depressão Central, and Grandes Lagoas, from September to December of 1999 (Spring-Summer season). Green pepper (Capsicum annuum) fruits were used as a host to enrich for pectolytic erwinia from potato stems with blackleg symptoms. Bacteria were subsequently isolated on non-selective medium. Isolates that were Gram-negative, facultatively anaerobic, and pitted crystal-violet-pectate medium were tested for biochemical traits to identify the species and subspecies. Four hundred strains were identified as either Eca, Ecc or Ech. Although the three erwinias were found in RS potato fields, only three strains of Ech were found in one field. Frequencies of Eca and Ecc were 55 and 42%, respectively. Eight strains could not be assigned based on the biochemical characterization.

Controle biológico de Colletotrichum acutatum, agente causal da queda prematura dos frutos cítricos

O trabalho teve por finalidade estudar a potencialidade antagonística de isolados de Bacillus subtilis a Colletotrichum acutatum, agente causal da queda prematura dos frutos cítricos (Citrus spp.) (QPFC), sob condições de laboratório e de campo. Foram estudados 64 isolados de B. subtilis, quatro isolados de Bacillus spp. e um isolado de B. thuringiensis quanto à capacidade de inibir o desenvolvimento do patógeno em cultura pareada e quanto à produção de metabólitos com atividade antimicrobiana. Os isolados mais promissores foram testados em condições de campo para controle da doença. In vitro, todos os isolados de Bacillus spp. inibiram o crescimento de C. acutatum, não havendo diferenças significativas entre eles. Os isolados de Bacillus spp. produziram, in vitro, metabólitos capazes de inibir o crescimento micelial de C. acutatum, os quais mantiveram suas atividades capazes de causar a inibição, após autoclavagem a 120 ºC, durante 20 min. Dentre os sete isolados de B. subtilis testados para o controle da QPFC, em condições naturais, o ACB-69 diferiu da testemunha e de vários outros isolados, porém equiparou-se estatisticamente ao benomyl, proporcionando menor porcentagem de flores com sintomas e maior número médio de frutos efetivos. Ainda, sob condições de campo, isolados de cada uma das espécies Trichoderma viride, T. pseudokoningii e T. aureoviride foram ineficientes, apresentando o mesmo comportamento da testemunha. Em relação aos métodos de avaliação da doença, a porcentagem de flores com sintomas foi mais eficiente do que o número médio de frutos efetivos (NMFE), uma vez que esses resultam do efeito direto do patógeno.