BIOSYSTEMATIC STUDIES IN THE BOUTELOUA CURTIPENDULA COMPLEX. I. THE ANEUPLOID RHIZOMATOUS B. CURTIPENDULA OF TEXAS

Gould , F. W., and Z. J. Kapadia . (A. & M. College of Texas, College Station.) Biosystematic studies in the Bouteloua curtipendula complex. I. The aneuploid rhizomatous B. curtipendula of Texas. Amer. Jour. Bot. 49(8): 887–891. Illus. 1962.—Widespread throughout central U.S. is a rhizomatous form of B. curtipendula that basically is tetraploid (2n = 40). In the southwest the predominant type is a caespitose aneuploid with a high chromosome number (2n = ca. 80 to 2n = ca. 102). The present study has shown the presence of an extensive series of rhizomatous aneuploids in central Texas, with chromosome numbers ranging from 2n = 41 to 2n = 64. The distribution of these plants is centered about the region of overlap in the ranges of the 2 previously mentioned types. Available evidence indicates that the rhizomatous aneuploids have arisen through hybridization of the caespitose aneuploids and the rhizomatous tetraploids.     

Biology and comparative predation efficacy of three heteropteran species recorded as predators ofBemisia tabaci in Maharashtra

Two mirids,Deraeocoris sp. andCampylomma nicolasi Reuter and one lygaeid,Geocoris ochropterus Fieber were found preying onB. tabaci (Gennadius) for the first time in Maharashtra State of India during 1987–88. Their biology and predation capacity onB. tabaci were studied in detail under laboratory conditions. The nymphal stage ofDeraeocoris sp. passed through 6 instars, whereas 5 instars in case of the remaining species.G. ochropterus, Deraeocoris sp. andC. nicolasi consumed on an average 482.5, 275.3 and 128.8 nymphs of 57.3, 25.5 and 20.6 days, respectively. On the basis of consumption rate per day,Deraeocoris sp. proved to be a superior predator. Part of Ph. D. Thesis submitted to Marathwada Agricultural University, Parbhani 431402, India.     

Stargardt's macular dystrophy

Stargardt's disease is the most common hereditary macular dystrophy with an estimated incidence of 1 in 10000. The typical patient presents with visual symptoms between the first and third decades of life. This paper will discuss a patient who was diagnosed with Stargardt's macular dystrophy (SMD) at an older age. The clinical characteristics, functional testing, histopathology, differential diagnosis and recent genetics advances related to SMD will be discussed in this report.     

Melovinone,an open chain analogue of melochinone from Melochia tomentosa

Melovinone, a new alkaloid isolated from the roots of Melochia tomentosa has been characterized as 3,7,8-trimethoxy-2-methyl-5(5′-phenylpentyl)-4-quinolinone.     

Nitric oxide regulates the 26S proteasome in vascular smooth muscle cells

It is well established that nitric oxide (NO) inhibits vascular smooth muscle cell (VSMC) proliferation by modulating cell cycle proteins. The 26S proteasome is integral to protein degradation and tightly regulates cell cycle proteins. Therefore, we hypothesized that NO directly inhibits the activity of the 26S proteasome. The three enzymatic activities (chymotrypsin-like, trypsin-like and caspase-like) of the 26S proteasome were examined in VSMC. At baseline, caspase-like activity was approximately 3.5-fold greater than chymotrypsin- and trypsin-like activities. The NO donor S-nitroso-N-acetylpenicillamine (SNAP) significantly inhibited all three catalytically active sites in a time- and concentration-dependent manner (P < 0.05). Caspase-like activity was inhibited to a greater degree (77.2% P < 0.05). cGMP and cAMP analogs and inhibitors had no statistically significant effect on basal or NO-mediated inhibition of proteasome activity. Dithiothreitol, a reducing agent, prevented and reversed the NO-mediated inhibition of the 26S proteasome. Nitroso-cysteine analysis following S-nitrosoglutathione exposure revealed that the 20S catalytic core of the 26S proteasome contains 10 cysteines which were S-nitrosylated by NO. Evaluation of 26S proteasome subunit protein expression revealed differential regulation of the α and β subunits in VSMC following exposure to NO. Finally, immunohistochemical analysis of subunit expression revealed distinct intracellular localization of the 26S proteasomal subunits at baseline and confirmed upregulation of distinct subunits following NO exposure. In conclusion, NO reversibly inhibits the catalytic activity of the 26S proteasome through S-nitrosylation and differentially regulates proteasomal subunit expression. This may be one mechanism by which NO exerts its effects on the cell cycle and inhibits cellular proliferation in the vasculature.     

Spontaneous mutations in recombinant inbred mice: mutant toll-like receptor 4 (Tlr4) in BXD29 mice

Recombinant inbred (RI) mice are frequently used to identify QTL that underlie differences in measurable phenotypes between two inbred strains of mice. Here we show that one RI strain, C57BL/6J x DBA/2J (BXD29), does not develop an inflammatory response following inhalation of LPS. Approximately 25% of F2 mice [F1(BXD29 x DBA/2J) x F1] are also unresponsive to inhaled LPS, suggesting the presence of a recessive mutation in the BXD29 strain. A genomic scan of these F2 mice revealed that unresponsive animals, but not responsive animals, are homozygous for C57BL/6J DNA at a single locus on chromosome 4 close to the genomic location of Tlr4. All progeny between BXD29 and gene-targeted Tlr4-deficient mice are unresponsive to inhaled LPS, suggesting that the mutation in the BXD29 strain is allelic with Tlr4. Moreover, the intact Tlr4 receptor is not displayed on the cell surface of BXD29 macrophages. Finally, a molecular analysis of the Tlr4 gene in BXD29 mice revealed that it is interrupted by a large insertion of repetitive DNA. These findings explain the unresponsiveness of BXD29 mice to LPS and suggest that data from BXD29 mice should not be included when using BXD mice to study phenotypes affected by Tlr4 function. Our results also suggest that the frequency of such unidentified, spontaneously occurring mutations is an issue that should be considered when RI strains are used to identify QTL.