Phylogenetics of Tribe Collabieae (Orchidaceae,Epidendroideae) Based on Four Chloroplast Genes with Morphological Appraisal

Collabieae (Orchidaceae) is a long neglected tribe with confusing tribal and generic delimitation and little-understood phylogenetic relationships. Using plastid matK, psaB, rbcL, and trnH-psbA DNA sequences and morphological evidence, the phylogenetic relationships within the tribe Collabieae were assessed as a basis for revising their tribal and generic delimitation. Collabieae (including the previously misplaced mycoheterotrophic Risleya) is supported as monophyletic and nested within a superclade that also includes Epidendreae, Podochileae, Cymbidieae and Vandeae. Risleya is nested in Collabiinae and sister to Chrysoglossum, a relationship which, despite their great vegetative differences, is supported by floral characters. Ania is a distinct genus supported by both morphological and molecular evidence, while redefined Tainia includes Nephelaphyllum and Mischobulbum. Calanthe is paraphyletic and consists four clades; the genera Gastrorchis, Phaius and Cephalantheropsis should be subsumed within Calanthe. Calanthe sect. Ghiesbreghtia is nested within sect. Calanthe, to which the disputed Calanthe delavayi belongs as well. Our results indicate that, in Collabieae, habit evolved from being epiphytic to terrestrial.     

The metalloproteinase ADAM‐12 regulates bronchial epithelial cell proliferation and apoptosis

Abstract. Objectives: The ADAMs (a disintegrin and metalloproteinase) enzymes compose a family of membrane‐bound proteins characterized by their multi‐domain structure and ADAM‐12 expression is elevated in human non‐small cell lung cancers. The aim of this study was to investigate the roles played by ADAM‐12 in critical steps of bronchial cell transformation during carcinogenesis. Materials and methods: To assess the role of ADAM‐12 in tumorigenicity, BEAS‐2B cells were transfected with a plasmid encoding human full‐length ADAM‐12 cDNA, and then the effects of ADAM‐12 overexpression on cell behaviour were explored. Treatment of clones with heparin‐binding epidermal growth factor (EGF)‐like growth factor (HB‐EGF) neutralizing antibodies as well as an EGFR inhibitor allowed the dissection of mechanisms regulating cell proliferation and apoptosis. Results: Overexpression of ADAM‐12 in BEAS‐2B cells promoted cell proliferation. ADAM‐12 overexpressing clones produced higher quantities of HB‐EGF in their culture medium which may rely on membrane‐bound HB‐EGF shedding by ADAM‐12. Targeting HB‐EGF activity with a neutralizing antibody abrogated enhanced cell proliferation in the ADAM‐12 overexpressing clones. In sharp contrast, targeting of amphiregulin, EGF or transforming growth factor‐α failed to influence cell proliferation; moreover, ADAM‐12 transfectants were resistant to etoposide‐induced apoptosis and the use of a neutralizing antibody against HB‐EGF activity restored rates of apoptosis to be similar to controls.Conclusions: ADAM‐12 contributes to enhancing HB‐EGF shedding from plasma membranes leading to increased cell proliferation and reduced apoptosis in this bronchial epithelial cell line.     

Ribosomal subunits and ribosomal proteins of Tetrahymena thermophila. Effect of the presence of iodoacetamide during ribosome extraction on the properties of the subunits

Proteolytic degradation of ribosomal proteins occurs during the preparation of subunits of the cytoplasmic ribosomes of the protozoa Tetrahymena thermophila and the isolated subunits are inactive. Addition of 5 mM iodoacetamide to cell suspensions before extraction inhibits proteolytic activity and permits isolation of active subunits. The protein complements of these subunits have been characterized in two different two-dimensional electrophoretic systems, and their molecular weights have been determined.     

Effect of a Low-Protein Diet Supplemented with Ketoacids on Skeletal Muscle Atrophy and Autophagy in Rats with Type 2 Diabetic Nephropathy

A low-protein diet supplemented with ketoacids maintains nutritional status in patients with diabetic nephropathy. The activation of autophagy has been shown in the skeletal muscle of diabetic and uremic rats. This study aimed to determine whether a low-protein diet supplemented with ketoacids improves muscle atrophy and decreases the increased autophagy observed in rats with type 2 diabetic nephropathy. In this study, 24-week-old Goto-Kakizaki male rats were randomly divided into groups that received either a normal protein diet (NPD group), a low-protein diet (LPD group) or a low-protein diet supplemented with ketoacids (LPD+KA group) for 24 weeks. Age- and weight-matched Wistar rats served as control animals and received a normal protein diet (control group). We found that protein restriction attenuated proteinuria and decreased blood urea nitrogen and serum creatinine levels. Compared with the NPD and LPD groups, the LPD+KA group showed a delay in body weight loss, an attenuation in soleus muscle mass loss and a decrease of the mean cross-sectional area of soleus muscle fibers. The mRNA and protein expression of autophagy-related genes, such as Beclin-1, LC3B, Bnip3, p62 and Cathepsin L, were increased in the soleus muscle of GK rats fed with NPD compared to Wistar rats. Importantly, LPD resulted in a slight reduction in the expression of autophagy-related genes; however, these differences were not statistically significant. In addition, LPD+KA abolished the upregulation of autophagy-related gene expression. Furthermore, the activation of autophagy in the NPD and LPD groups was confirmed by the appearance of autophagosomes or autolysosomes using electron microscopy, when compared with the Control and LPD+KA groups. Our results showed that LPD+KA abolished the activation of autophagy in skeletal muscle and decreased muscle loss in rats with type 2 diabetic nephropathy.