Comparative pathology of neurovirulent lineage 1 (NY99/385) and lineage 2 (SPU93/01) West Nile virus Infections in BALBc mice

The pathology in mice infected with neurovirulent South African lineage 2 West Nile virus (WNV) strains has not previously been described. Three- to 4-month-old male BALBc mice were infected with South African neurovirulent lineage 2 (SPU93/01) or lineage 1 (NY385/99) WNV strains and the gross and microscopic central nervous system (CNS) and extra-CNS pathology of both investigated and compared. Mice infected with both lineages showed similar illness, paralysis, and death from days 7 to 11 postinfection (PI). Two survivors of each lineage were euthanized on day 21 PI. WNV infection was confirmed by nested real-time reverse transcription polymerase chain reaction of tissues, mostly brain, in the majority of mice euthanized sick or that died and in 1 healthy lineage 2 survivor. Gross lesions caused by both lineages were identical and included marked gastric and proximal small intestinal fluid distension as described in a previous mouse study, but intestinal microscopic lesions differed. CNS lesions were subtle. Immunohistochemical (IHC)–positive labeling for WNV E protein was found in neurons multifocally in the brain of 3 lineage 1–infected and 3 lineage 2–infected mice from days 9 to 11 PI, 4 of these including brainstem neurons, and of cecal myenteric ganglion neurons in 1 lineage 2–infected day 8 PI mouse. Findings supported hypotheses in hamsters that gastrointestinal lesions are likely of brainstem origin. Ultrastructurally, virus-associated cytoplasmic vesicular or crystalline structures, or amorphous structures, were found to label IHC positive in control-positive avian cardiomyocytes and mouse thalamic neurons, respectively, and WNV-like 50-nm particles, which were scarce, did not label.National Research Foundation of South Africa and Pfizer Animal Health. Section of Pathology of the Department of Paraclinical Sciences of the Faculty of Veterinary Science, University of Pretoria, South Africa.http://vet.sagepub.comhb201

Do soil fertilization and forest canopy foliage affect the growth and photosynthesis of Amazonian saplings?

Most Amazonian soils are highly weathered and poor in nutrients. Therefore, photosynthesis and plant growth should positively respond to the addition of mineral nutrients. Surprisingly, no study has been carried out in situ in the central Amazon to address this issue for juvenile trees. The objective of this study was to determine how photosynthetic rates and growth of tree saplings respond to the addition of mineral nutrients, to the variation in leaf area index of the forest canopy, and to changes in soil water content associated with rainfall seasonality. We assessed the effect of adding a slow-release fertilizer. We determined plant growth from 2010 to 2012 and gas exchange in the wet and dry season of 2012. Rainfall seasonality led to variations in soil water content, but it did not affect sapling growth or leaf gas exchange parameters. Although soil amendment increased phosphorus content by 60 %, neither plant growth nor the photosynthetic parameters were influenced by the addition of mineral nutrients. However, photosynthetic rates and growth of saplings decreased as the forest canopy became denser. Even when Amazonian soils are poor in nutrients, photosynthesis and sapling growth are more responsive to slight variations in light availability in the forest understory than to the availability of nutrients. Therefore, the response of saplings to future increases in atmospheric [CO2] will not be limited by the availability of mineral nutrients in the soil

Estudos morfoanatômicos da semente e da plântula de espécies de Anileiras (Indigofera L., Leguminosae) Morpho-anatomical studies of seeds and seedlings of wild indigo, "anileira", Indigofera- Leguminosae

O nome popular "anileira" designa Indigofera anil L., I. suffruticosa Mill. e I. truxillensis Kunth, muito semelhantes quanto à morfologia externa. Este trabalho teve por objetivo avaliar se caracteres da semente e plântula apresentavam valor diagnóstico para este grupo, já que tais caracteres têm sido muito utilizados na Taxonomia de Leguminosae. A superfície e morfoanatomia de sementes e cotilédones foram estudadas por microscopias eletrônica de varredura e de luz, e as etapas do desenvolvimento das plântulas descritas. Embora as plântulas sejam semelhantes, caracteres de sementes (tamanho, forma, ornamentação da superfície, forma do hilo e tamanho do embrião) e cotilédones (forma, organização do parênquima lacunoso na nervura central e distribuição de metabólitos nos tecidos) apresentaram valor diagnóstico para as espécies. I. anil distingue-se de I. suffruticosa por suas sementes maiores e cotilédones com borda acuminada. I. truxillensis caracteriza-se por apresentar sementes cilíndricas e cotilédones reniformes contendo gotas de óleo e alcalóides. Nossos dados, a morfologia externa dos frutos (curvos em I. anil e I. suffruticosa, e retos em I. truxillensis) e, ainda, a anatomia foliar (células parenquimáticas grandes e fenólicas no floema de I. suffruticosa e sua ausência em I. anil) sugerem que I. anil, I. suffruticosa e I. truxillensis não devem ser sinonimizadas.<br>The common name "wild indigo" specifies Indigofera anil L., I. suffruticosa Mill. (legitimate name) and I. truxillensis Kunth (legitimate name) that are very similar due to their external morphology. This work analyzed diagnostic characteristics of seeds and seedlings of these species since such features are widely used in taxonomic approaches within Leguminosae. We studied surface features and morpho-anatomy of seeds and cotyledons with scanning electronic microscopy and light microscopy, and described seedling phases. Although seedlings are similar, seed characteristics (size, shape, surface ornamentation, shape of the hilum and embryo size) and cotyledon characteristics (shape, trichome ornamentation, organization of spongy parenchyma along central veins and metabolite distribution in the tissues) have diagnostic features for the species. I. anil differs from I. suffruticosa in its larger seeds and acuminate-margined cotyledons. I. truxillensis is recognized by its cylindrical seeds and kidney-shaped cotyledons with large oil drops. We assume that the characteristics examined, plus fruit morphology and foliar anatomy suggest that I. anil, I. suffruticosa and I. truxillensis should not be synonymized