Development and validation of the Axiom®Apple480K SNP genotyping array

Cultivated apple (Malus × domestica Borkh.) is one of the most important fruit crops in temperate regions, and has great economic and cultural value. The apple genome is highly heterozygous and has undergone a recent duplication which, combined with a rapid linkage disequilibrium decay, makes it difficult to perform genome‐wide association (GWA) studies. Single nucleotide polymorphism arrays offer highly multiplexed assays at a relatively low cost per data point and can be a valid tool for the identification of the markers associated with traits of interest. Here, we describe the development and validation of a 487K SNP Affymetrix Axiom^® genotyping array for apple and discuss its potential applications. The array has been built from the high‐depth resequencing of 63 different cultivars covering most of the genetic diversity in cultivated apple. The SNPs were chosen by applying a focal points approach to enrich genic regions, but also to reach a uniform coverage of non‐genic regions. A total of 1324 apple accessions, including the 92 progenies of two mapping populations, have been genotyped with the Axiom^®Apple480K to assess the effectiveness of the array. A large majority of SNPs (359 994 or 74%) fell in the stringent class of poly high resolution polymorphisms. We also devised a filtering procedure to identify a subset of 275K very robust markers that can be safely used for germplasm surveys in apple. The Axiom^®Apple480K has now been commercially released both for public and proprietary use and will likely be a reference tool for GWA studies in apple.     

Selective neurotoxicity of ruthenium red in primary cultures

The inorganic dye ruthenium red (RuR) has been shown to be neurotoxic in vivo when injected intracerebrally. In this work toxicity of RuR was compared in primary cultures of rat cotical neurons, cerebellar granule neurons and cerebellar astroglia. Microscopic examination of the cultures revealed that RuR penetrates the somata of both types of neurosn used and produces vacuolization and loss and fragmentation of neurites. In contrast, no RuR was seen inside cultured astrocytes and no morphological signs of damage were observed in these cells. RuR toxicity wa also assessed by immunocytochemistry of -tubulin and by biochemical measurement of the reduction of (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) by the cultured cells. The morphological alteratios in the neuros were closely correlated with loss of tubulin immunoreactivity and partivular with a notable decrement in the ability to reduce MTT. Using the latter parameter, it was found that neuronal damage was independent of the age of the cultures, augmented progressively with time of incubation with RuR, from 8 to 24 h, and showed a clear dose-response curve from 20 to 100 M RuR. Astrocytes showed only a slight decrease in MTT reduction after 24 h of incubation with 100 M RuR. It is concluded that RuR seems to be toxic for neurons but not for astroglia, and that this selectivity is probably related to the ability of the neurons to internalize the dye. The possible mechanisms ofRuR penetration and neuronal damage are discussed.Special issue dedicated to Dr. Robert Balázs.     

Decoupled responses of biodiversity facets driven from anuran vulnerability to climate and land-use changes

Biodiversity loss not only implies the loss of species but also entails losses in other dimensions of biodiversity, such as functional, phylogenetic and interaction diversity. Yet, each of those facets of biodiversity may respond differently to extinctions. Here, we examine how extinction, driven by climate and land-use changes may affect those different facets of diversity by combining empirical data on anuran–prey interaction networks, species distribution modelling and extinction simulations in assemblages representing four Neotropical ecoregions. We found a mismatch in the response of functional, phylogenetic and interaction diversity to extinction. In spite of high network robustness to extinction, the effects on interaction diversity were stronger than those on phylogenetic and functional diversity, declining linearly with species loss. Although it is often assumed that interaction patterns are reflected by functional diversity, assessing species interactions may be necessary to understand how species loss translates into the loss of ecosystem functions.     

The effect of low temperatures on ultrastructure of hyphae and young zygospores ofRhizopus sexualis (Smith) Callen

Summary Aerial hyphae and young zygospores ofR. sexualis were exposed to a temperature of 7 °C for periods of 6 to 72 hours. The zonation of organelles seen in the apices of hyphae grown at 20 °C was lost by treatment at 7 °C. In particular the small vesicles normally present at the apex were absent. The shape and alignment of mitochondria was altered in a manner suggesting cessation of cytoplasmic streaming. Small vacuoles coalesced to form fewer large ones. With longer exposure to low temperature the mitochondrial cristae were altered in form and the membranes of the nuclear envelope tended to separate. The amount of endoplasmic reticulum associated with nuclei was reduced. Similar changes occurred in young zygospores, and in addition the normal processes of dissolution of the fusion wall and formation of gametangial septa were disrupted and the vesicles associated with these processes largely disappeared. The significance of these ultrastructural changes is discussed in relation to the known effects of low temperature on zygospore development.     

Orbital muscle of Müller: observations on human fetuses measuring 35-150 mm

The arrangement and relationships of the orbital muscle of Müller in human fetuses have been analyzed. This is a constant muscle made of smooth muscle fibers arranged over the longer axis of the inferior orbital fissure; some of its fibers reach the inferior wall of the cavernous sinus. The muscle layer is pierced by orbital rami of the medial maxillary artery and by thin veins communicating with the ophthalmic vein system and pterygoid plexus. The zygomatic nerve can be found in the midst of the muscle mass along most of its course. It is innervated by short rami from the sphenopalatine ganglion.     

试管苗嫩枝顶端嫁接技术的研究

根据植物顶端生长优势的原理,在猕猴桃(Actinidia chinensis)胚乳培养中,将愈伤组织上分化的芽,切割下来作接穗,利用简单装置,进行“嫩枝顶端嫁接”,嫁接成活率高达90%左右,并至少提前1—2年开花、结果。利用嫩枝顶端嫁接技术,不仅提高了试管苗的成活率,而且在简化培养程序、缩短培养周期、降低培养成本上都有明显的效果。     

Loss of the nutrient sensor TAS1R3 leads to reduced bone resorption

The taste receptor type 1 (TAS1R) family of heterotrimeric G protein-coupled receptors participates in monitoring energy and nutrient status. TAS1R member 3 (TAS1R3) is a bi-functional protein that recognizes amino acids such as L-glycine and L-glutamate or sweet molecules such as sucrose and fructose when dimerized with TAS1R member 1 (TAS1R1) or TAS1R member 2 (TAS1R2), respectively. It was recently reported that deletion of TAS1R3 expression in Tas1R3 mutant mice leads to increased cortical bone mass but the underlying cellular mechanism leading to this phenotype remains unclear. Here, we independently corroborate the increased thickness of cortical bone in femurs of 20-week-old male Tas1R3 mutant mice and confirm that Tas1R3 is expressed in the bone environment. Tas1R3 is expressed in undifferentiated bone marrow stromal cells (BMSCs) in vitro and its expression is maintained during BMP2-induced osteogenic differentiation. However, levels of the bone formation marker procollagen type I N-terminal propeptide (PINP) are unchanged in the serum of 20-week-old Tas1R3 mutant mice as compared to controls. In contrast, levels of the bone resorption marker collagen type I C-telopeptide are reduced greater than 60% in Tas1R3 mutant mice. Consistent with this, Tas1R3 and its putative signaling partner Tas1R2 are expressed in primary osteoclasts and their expression levels positively correlate with differentiation status. Collectively, these findings suggest that high bone mass in Tas1R3 mutant mice is due to uncoupled bone remodeling with reduced osteoclast function and provide rationale for future experiments examining the cell-type-dependent role for TAS1R family members in nutrient sensing in postnatal bone remodeling.     

Parenting styles in white‐rumped swallows (Tachycineta leucorrhoa) show a trade‐off between nest defense and chick feeding

Studies about personalities in wild animals usually focus on five categories of behavioral traits that do not easily accommodate all aspects of parental care, a class of behaviors with direct consequence to reproductive success. Parental care can vary consistently between individuals and constitute parenting styles. Here we investigate the consistency of four behaviors of parental care across two breeding seasons of white‐rumped swallows Tachycineta leucorrhoa in southern Brazil. These behaviors are a prospection of potential nest‐sites, nest defense against predators or conspecifics, and chick feeding. If these first three behaviors are consistent, they can be classified according to the standard categories of personality as exploration, boldness, and aggressiveness, respectively. We find that all behaviors, except exploration, are consistent between individuals in the long term. We also show that, besides individual identity, couple identity is an important component explaining variation in behavior. This pattern can arise if behavior influences pair formation or if behavior is a consequence of a common environment affecting the couple. We show that, depending on the parental task, males or females are more consistent, suggesting that sexes are adopting different strategies of parental care allocation. We then investigate if there is a trade‐off between nest defense and chick feeding. We find that birds that defend more also feed the brood less often and suggest that testosterone might be the mechanism modulating this trade‐off. Lastly, we discuss the implications of our results to mate choice and highlight the need for studies linking parenting styles to fitness in swallow species.