Development of an efficient regeneration and Agrobacterium-mediated transformation system in crab apple (Malus micromalus) using cotyledons as explants

Apple has become a model species for Rosaceae genetic and genomic research, but it is difficult to obtain transgenic apple plants by Agrobacterium-mediated transformation using in vitro leaves as explants. In this study, we developed an efficient regeneration and Agrobacterium-mediated transformation system for crab apple (Malus micromalus) using cotyledons as explants. The proximal cotyledons of M. micromalus, excised from seedlings that emerged from mature embryos cultured for 10–14 d in vitro, were suitable as explants for regeneration and Agrobacterium-mediated transformation. Cotyledon explants were cocultivated for 3 d with Agrobacterium tumefaciens strain EHA105 harboring the binary vector pCAMBIA2301 on regeneration medium. Kanamycin-resistant buds were produced on cotyledon explants cultured on selective regeneration medium containing 20 mg/L kanamycin. Acetosyringone supplemented in the Agrobacterium suspension or in the cocultivation medium slightly enhanced the regeneration of kanamycin-resistant buds. The maximum percentage of explants with kanamycin-resistant buds was 11.7%. The putative transformed plants were confirmed by histochemical analysis of β-glucuronidase activity and the polymerase chain reaction amplification of the neomycin phosphotransferase II gene. This transformation system also enables recovery of nontransformed isogenic controls developed from embryo buds and is therefore suitable for functional genomics studies in apple.     

A taxonomic study of the genus Panesthia (Blattodea,Blaberidae, Panesthiinae) from China with descriptions of one new species,one new subspecies and the male of Panesthia antennata

One new species Panesthia guizhouensis sp. n. and one new subspecies Panesthia stellata concava ssp. n. are described and illustrated. The male of Panesthia antennata Brunner von Wattenwyl, 1893 and its brachypterous form are described and illustrated for the first time. Panesthia strelkovi Bey-Bienko, 1969 is redescribed and illustrated. Three known species, Panesthia birmanica Brunner von Wattenwyl, 1893, Panesthia sinuata Saussure, 1839 and Panesthia angustipennis cognata Bey-Bienko, 1969 are illustrated. In addition, a key to all species of the genus Panesthia from China is presented.     

A Liquid Chromatography-Mass Spectrometry-based Approach to Characterize the Substrate Specificity of Mammalian Heparanase

Extracellular heparanase activity releases growth factors and angiogenic factors from heparan sulfate (HS) storage sites and alters the integrity of the extracellular matrix. These activities lead to a loss of normal cell matrix adherent junctions and correlate with invasive cellular phenotypes. Elevated expression of heparanase is associated with several human cancers and with vascular remodeling. Heparanase cleaves only a limited fraction of glucuronidic linkages in HS. There have been few investigations of the functional consequences of heparanase activity, largely due to the heterogeneity and complexity of HS. Here, we report a liquid chromatography-mass spectrometry (LC-MS)-based approach to profile the terminal structures created by heparanase digestion and reconstruct the heparanase cleavage sites from the products. Using this method, we demonstrate that heparanase cleaves at the non-reducing side of highly sulfated HS domains, exposing cryptic growth factor binding sites. This cleavage pattern is observed in HS from several tissue sources, regardless of overall sulfation degree, indicating a common recognition pattern. We further demonstrate that heparanase cleavage of HS chains leads to increased ability to support FGF2-dependent cell proliferation. These results suggest a new mechanism to explain how heparanase might potentiate the uncontrolled cell proliferation associated with cancer through its ability to activate nascent growth factor-promoting domains within HS.     

On the Origin and Evolution of Plant Brassinosteroid Receptor Kinases

Brassinosteroid (BR) signaling pathway is so far the best-understood receptor-kinase signaling pathway in plants. In Arabidopsis, the activation of this pathway requires binding of BRs to the receptor kinase BRASSINOSTEROID-INSENSITIVE I (AtBRI1). Although the function of AtBRI1 has been extensively studied, it is not known when the binding function emerged and how this important component of BR signaling pathway and related genes (the BRI1–BRL gene family) have evolved in plants. We define BRI1–BRL genes in sequenced plant genomes, construct profiles for critical protein domains, scan them against all accessible plant gene/EST resources, and reveal the evolution of domain configuration of this family. We also investigate its evolutionary pattern through phylogenetic analysis. The complete BR receptor domain configuration originates through two domain gain events in the ancestral receptor-like kinase: first juxtamembrane domain gained during the early diversification of land plants, and then island domain (ID) acquired in the common ancestor of angiosperms and gymnosperms after its divergence from spike moss. The 70 amino acid ID has characteristic sequences of BRI1–BRL family and this family keeps relative stable copy numbers during the history of angiosperms and the majority of duplications and losses have occurred in terminal taxa in current taxon sampling. This study reveals important events shaping structural and functional characteristics of plant BR receptors. It answers the question of how and when BR receptors originates, which provide insights into the origin and evolution of the BR signaling pathway.