Castanea spp. biodiversity conservation: collection and characterization of the genetic diversity of an endangered species

Centuries of co-evolution between Castanea spp. biodiversity and human populations has resulted in the spread of rich and varied chestnut genetic diversity throughout most of the world, especially in mountainous and forested regions. Its plasticity and adaptability to different pedoclimates and the wide genetic variability of the species determined the spread of many different ecotypes and varieties in the wild. Throughout the centuries, man has used, selected and preserved these different genotypes, vegetatively propagating them by grafting, for many applications: fresh consumption, production of flour, animal nutrition, timber production, thereby actively contributing to the maintenance of the natural biodiversity of the species, and providing an excellent example of conservation horticulture. Nonetheless, currently the genetic variability of the species is critically endangered and hundreds of ecotypes and varieties are at risk of being lost due to a number of phytosanitary problems (canker blight, Chryphonectria parasitica; ink disease, Phytophthora spp.; gall wasp, Dryocosmus kuriphilus), and because of the many years of decline and abandonment of chestnut cultivation, which resulted in the loss of the binomial male chestnut. Recently, several research and experimentation programmes have attempted to develop strategies for the conservation of chestnut biodiversity. The purpose of this paper is to give an overview of the status of biodiversity conservation of the species and to present the results of a 7?year project aimed at the individuation and study of genetic diversity and conservation of Castanea spp. germplasm.     

Identification of positive cells to interleukin-4 in bovine haemal nodes

The bovine haemal nodes are lymphatic organs located in the haemal circulation. Their parenchyma is represented by plasma cells, macrophages and B and T lymphocytes. The T helper type 2 (Th2) CD4 lymphocyte can be found within the T lymphocytes. The activated Th2 CD4 lymphocyte produces interleukin-4 (IL-4), a peptidic hormone involved in the acute-phase immune response. This interleukin can promote either B-lymphocyte differentiation and T-lymphocyte proliferation or it can promote the type of immunoglobulin that can be liberated. Our results have shown, by immunostaining with anti-IL-4, not only the presence and localization of these lymphocytes in bovine haemal nodes but also the participation of polymorphonuclear cells (neutrophils) in the storage of IL-4. These results give value to the humoral and cellular immunological importance of haemal nodes in bovines and they can serve as a contribution to determine the cross-reactivity of bovine IL-4 with the human anti-serum used in this work.     

Prooxidant states and tumor promotion

There is convincing evidence that cellular prooxidant states--that is, increased concentrations of active oxygen and organic peroxides and radicals--can promote initiated cells to neoplastic growth. Prooxidant states can be caused by different classes of agents, including hyperbaric oxygen, radiation, xenobiotic metabolites and Fenton-type reagents, modulators of the cytochrome P-450 electron-transport chain, peroxisome proliferators, inhibitors of the antioxidant defense, and membrane-active agents. Many of these agents are promoters or complete carcinogens. They cause chromosomal damage by indirect action, but the role of this damage in carcinogenesis remains unclear. Prooxidant states can be prevented or suppressed by the enzymes of the cellular antioxidant defense and low molecular weight scavenger molecules, and many antioxidants are antipromoters and anticarcinogens. Finally, prooxidant states may modulate the expression of a family of prooxidant genes, which are related to cell growth and differentiation, by inducing alterations in DNA structure or by epigenetic mechanisms, for example, by polyadenosine diphosphate-ribosylation of chromosomal proteins.     

Potential for increasing the zinc content in common bean using genetic improvement

A large proportion of the world’s population is at risk of developing symptoms of zinc deficiency due to its low levels in food. The objective of this research was to estimate the heritability in early hybrid generations for the zinc content character in seeds of common bean (Phaseolus vulgaris L.), to investigate possible maternal effects on zinc contents and to evaluate the potential for genetic improvement. Reciprocal F₁, and F₂ generations as well as backcross (RCP₁ and RCP₂) populations were produced by crosses of three cultivars. The seed zinc content was measured by the nitric-perchloric digestion method and using the atomic absorption spectrophotometer. The range of variation in zinc content among tested progenies was from 21.76 mg kg⁻¹ dry matter to 53.48 mg kg⁻¹ dry matter, and no significant maternal effect was discovered. Narrow sense heritability was of an intermediate 57.5% to high 77.84% value and transgressive segregation was observed. These results suggest that breeding for increased zinc content in the seeds of common bean can be quite successful; an increase of 37.3% was obtained using just the three parents tested in this study.     

The Chlamydomonas genome reveals the evolution of key animal and plant functions

Chlamydomonas reinhardtii is a unicellular green alga whose lineage diverged from land plants over 1 billion years ago. It is a model system for studying chloroplast-based photosynthesis, as well as the structure, assembly, and function of eukaryotic flagella (cilia), which were inherited from the common ancestor of plants and animals, but lost in land plants. We sequenced the approximately 120-megabase nuclear genome of Chlamydomonas and performed comparative phylogenomic analyses, identifying genes encoding uncharacterized proteins that are likely associated with the function and biogenesis of chloroplasts or eukaryotic flagella. Analyses of the Chlamydomonas genome advance our understanding of the ancestral eukaryotic cell, reveal previously unknown genes associated with photosynthetic and flagellar functions, and establish links between ciliopathy and the composition and function of flagella.     

A Scanning and Immunohistochemical Study in Bovine Haemal Node

The bovine haemal nodes are lymphatic organs with haemal circulation. The blood circulates inside of them through virtual cavities named sinuses. In these sinuses there is passage of cells and particulate materials from parenchyma to sinuses and vice versa. For this passage temporal overtures exist in the sinus walls. The sinus wall is composed of endothelial cells, basal membrane and reticular cells. Our results have demostrated that type IV collagen was one of the basal membrane constituents in bovine haemal nodes and by this constitution a dynamic equilibrium of the sinus walls was permitted.     

From Farmers to Loggers: The Role of Shifting Cultivation Landscapes in Timber Production in Cameroon

This article focuses on timber sourced from the agricultural areas in the shifting cultivation landscapes of the Central Region of Cameroon. Data about volumes marketed in urban centres, harvesting operations and on-farm timber management are used to discuss the ecological impact of small-scale logging and its sustainability in the long term. An opportunistic association exists between small-scale logging and agricultural land uses, determined mostly by the abundance of valuable species in fallows and on cocoa farms, their easy accessibility and the low price of farmland timber. Farmers apply various strategies to the management of tree resources in fallows and cocoa agroforests, with most felling authorized in fallows and most trees preserved on the cocoa farms. With current agricultural expansion and intensification trends associated with small-scale logging, timber resources on rural land are at risk of depletion with direct consequences for domestic timber supply and the thousands of livelihoods it sustains. Marketing and regulatory changes are needed to encourage the integration of timber production in agricultural management systems.     

Peanut cake can replace soybean meal in supplements for lactating cows without affecting production

Tropical Animal Health and Production - This study evaluated the total replacement of soybean meal with peanut cake in the concentrate supplement of lactating cows grazing. Eight crossbred 5/8...