Leaf mutations induced in black gram by X-rays and EMS

Four new leaf mutants, crinkled-leaf, waxy-leaf, narrow-leaf and unifoliate were induced in black gram, Phaseolus mungo, following treatments with X-rays and/or ethyl methanesulfonate (EMS). The crinkled-leaf and waxy-leaf mutants had normal fertility and vitality, whereas the narrow-leaf mutant was partially sterile and the unifoliate (an extreme dwarf) completely sterile. All the mutants except unifoliate behaved as monogenic recessive to the normal.     

Characteristics of morphological changes in the myocardium of rats with different degrees of hereditary resistance to hypoxia during the development of adrenaline-induced myocardial dystrophy

By means of polarizational microscopy method morphological changes of the cardiac muscle have been studied in highly-(HS) and poorly-stable (PS) rats to hypoxia 1 h and 1 day after injection of cardiotoxic dose of adrenaline (1.5 mg/kg of body mass). One hour after injection of adrenaline in PS animals the II-III stages of contractive myofibrillar changes are revealed, while in HS rats--the I-II stages. In 1 day in the myocardium of PS animals contractures of the III-IV degree are observed, more foci of clumping decay and myocytolysis than in HS rats. Severity of the morphological changes of the cardiac muscle after cardiotoxic dose of adrenaline essentially depends on the organism's reactivity.     

Length-weight relationships of ornamental fish species from Amanã Lake,Amanã Reserve,Amazonas, Brazil

Length-weight relationships (LWRs) were estimated for 16 ornamental fish species from Amanã Lake and nine tributary streams, in Central Brazilian Amazonia. Sampling was carried out bimonthly for a year (2007–2008), using two sets of four gillnets (20 m × 2 m, 2,5; 3,5; 04; 4,5 cm stretch mesh size); trawls were performed with seine nets (35 m × 6 m, 3 mm stretch mesh size); native fish-traps (fyke-net like fish-traps woven from local lianas), and dip nets (0.5 m × 0.5 m stretch mesh size). Measurements were done for standard length (SL – 0.1 cm precision) and total weight (Wt – 0.01 g precision). This study provides information on the length–weight relationships for all sampled species and, in addition, provides new maximum standard lengths for six species.     

Almost half of the RTX domain is dispensable for complement receptor 3 binding and cell-invasive activity of the Bordetella adenylate cyclase toxin

The whooping cough agent Bordetella pertussis secretes an adenylate cyclase toxin (CyaA) that through its large carboxy-proximal Repeat-in-ToXin (RTX) domain binds the complement receptor 3 (CR3). The RTX domain consists of five blocks (I–V) of characteristic glycine and aspartate-rich nonapeptides that fold into five Ca²⁺-loaded parallel β-rolls. Previous work indicated that the CR3-binding structure comprises the interface of β-rolls II and III. To test if further portions of the RTX domain contribute to CR3 binding, we generated a construct with the RTX block II/III interface (CyaA residues 1132–1294) linked directly to the C-terminal block V fragment bearing the folding scaffold (CyaA residues 1562–1681). Despite deletion of 267 internal residues of the RTX domain, the Ca²⁺-driven folding of the hybrid block III/V β-roll still supported formation of the CR3-binding structure at the interface of β-rolls II and III. Moreover, upon stabilization by N- and C-terminal flanking segments, the block III/V hybrid-comprising constructs competed with CyaA for CR3 binding and induced formation of CyaA toxin-neutralizing antibodies in mice. Finally, a truncated CyaAΔ_1295-1561 toxin bound and penetrated erythrocytes and CR3-expressing cells, showing that the deleted portions of RTX blocks III, IV, and V (residues 1295–1561) were dispensable for CR3 binding and for toxin translocation across the target cell membrane. This suggests that almost a half of the RTX domain of CyaA is not involved in target cell interaction and rather serves the purpose of toxin secretion.