Identification of 57 conventional RFLP and 6 VNTR systems with 32 DNA clones on chromosome 11p15

Fifty-four clones containing human inserts were selected from a cosmid library constructed from a somatic cell hybrid containing chromosome 11p15.3-p15.5 as its only human complement. In 32 of these clones, 63 polymorphic systems were identified with a panel of restriction enzymes: 57 conventional RFLP systems and 6 highly polymorphic VNTR systems. Although we examined the cosmid with only seven enzymes, 18 clones (including 6 VNTRs) were polymorphic with three or more enzymes. The results suggested that DNA sequences on the peritelomeric region of chromosome 11p tend to be highly variable. Because these markers are highly informative, they will be excellent resources for investigations of hereditary diseases and tumor suppressor genes in this region of chromosome 11.     

Culture of Amelanchier x grandiflora in a programmable micropropagation apparatus

A micropropagation system was developed to test concepts for automation and microenvironment alteration. Amelanchier x grandiflora Rehd. Princess Diana (serviceberry) shoot cultures were grown in seven-liter polycarbonate containers. Through computer control, the apparatus intermittently applied culture medium to the plant material according to a selected schedule. Shoot growth in the programmable system was compared with four micropropagation treatments: gelled and liquid medium in baby food jars and gelled and non-cycling liquid medium in a seven-liter vessel. Plants cultured in continuous contact with liquid medium became increasingly vitrified. Significantly greater shoot number, shoot length, shoot weight, and culture weight occurred in the programmable system than in jars with gelled medium. The combination of liquid medium, 7-liter vessel, and intermittent contact with medium caused a significantly higher proliferation rate than any combination of jar/vessel and gelled/liquid medium tested.     

Interaction of two variable proteins (PilE and PilC) required for pilus-mediated adherence of Neisseria gonorrhoeae to human epithelial cells

Pili confer the initial ability of Neisseria gonorrhoeae to bind to epithelial cells. Pilin (PilE), the major pilus subunit, and a minor protein termed PilC, reportedly essential for pilus biogenesis, undergo intra-strain phase and structural variation. We demonstrate here that at least two different adherence properties are associated with the gonococcal pili: one is specific for erythrocytes, which is virtually unaffected by PilE variation, and another is specific for epithelial cells, and is modulated in response to the variation of PilE. Based on this finding, mutants of a recA- strain were selected that had lost the ability to bind to human cornea epithelial cells (A-) but retained the ability to form pili (P+) and to agglutinate human erythrocytes (H+). The adherence-negative mutants failed to produce detectable levels of PilC1 or PilC2 proteins, representing piIC phase variants generated in the absence of RecA. The A- pilC phase variants were indistinguishable from their A+ parents and spontaneous A+ revertants with regard to the amount of PilE produced and its electrophoretic mobility, the degrees of piliation and haemagglutination, and the pilE nucleotide sequence. These data demonstrate a central role for PilC in pilus-mediated adherence of N. gonorrhoeae to human epithelial cells and further indicate that neither PilC1 nor PilC2 is obligatory for the assembly of gonococcal pili.     

Seed morphology under SEM and light microscopy in Kansas Juncus (Juncaceae)

Seed morphology was studied in 15 species of four subgenera ofJuncus occurring in Kansas, to determine if seeds provide traits useful in assessing systematic relations within the genus. In this study seed size and shape were of limited value, while surface ornamentation of the hard inner seed coat provided encouraging results. SubgenusPoiophylli showed little variation in surface ornamentation among taxa; similar ornamentation was observed in subgenusGenuini. SubgeneraGraminifolii andSeptati were separately distinct with the taxa in theSeptati forming a continuum of variation.     

Genetic and developmental characterization of the aldox-2 locus of Drosophila melanogaster

The aldox-2 locus in Drosophila melanogaster has been shown to affect differentially three molybdoenzymes, aldehyde oxidase, pyridoxal oxidase, and xanthine dehydrogenase. These effects are most obvious at times surrounding the pupal-adult boundary, when the normal organism accumulates large amounts of these enzymes in their active form. This locus has been more precisely mapped genetically to 2-82.9 +/- 2.1, with complete concordance between the effects of all recombinant chromosomes on all three enzymes. The cytogenetic location has also been determined to be between 52E and 54E8, with the likelihood that it lies within the region 54B1-54E8. The aldox-2 mutant allele has no visible phenotype and is completely recessive for enzyme effects at all stages tested. Segmental duplication of this region, including the aldox-2+ allele, has no apparent effect on the visible phenotype or the enzymatic activity. The mutant aldox-2 allele has no effect on the developmental expression of two unrelated enzymes, 6-phosphogluconate dehydrogenase and NADP+-dependent isocitrate dehydrogenase. The effects of this locus on aldehyde oxidase, xanthine dehydrogenase, and pyridoxal oxidase suggest that this locus may code for a product involved in the synthesis of the molybdenum cofactor common to these enzymes.     

Localization of the ganglioside-binding site of fibronectin

It has been demonstrated via biological assays that fibronectin possesses a receptor for gangliosides that is involved in cell adhesion and restoration of the normal morphology of transformed cells. In this study, fluorescence polarization has been employed to monitor the binding of ganglioside oligosaccharide to fibronectin. Parameters involved in ganglioside oligosaccharide binding to fibronectin are described and compared to the interaction of heparin with fibronectin. A Kd of 1.4 X 10(-8) mol/liter has been calculated, and it is demonstrated that labeled ganglioside oligosaccharides can be eluted from fibronectin with either unlabeled ganglioside oligosaccharides or 4 M urea. Using the fluorescence polarization assay developed in this study for measurement of ganglioside binding to fibronectin, it is demonstrated that gangliosides bind to the 31,000-dalton amino terminal heparin-binding domain of fibronectin. A ganglioside-Sepharose affinity column has been constructed which specifically binds the 31,000-dalton amino terminal fragment of fibronectin. The localization of the ganglioside receptor to the amino terminal domain of fibronectin indicates that the ganglioside receptor is distinct from the putative fibronectin cell surface receptor which is located near the center of the fibronectin molecule.     

Improved Fixation of Cellulose-Acetate Reverse-Osmosis Membrane for Scanning Electron Microscopy

Fixation of cellulose-acetate membranes with either glutaraldehyde-osmium tetroxide or glutaraldehyde-ruthenium tetroxide resulted in extensive electron beam damage. Beam damage was eliminated and the bacterial surface structure was preserved, however, when cellulose-acetate membranes were fixed with glutaraldehyderuthenium tetroxide and treated successively with thiocarbohydrazide and osmium tetroxide.     

Circadian rhythms in Neurospora crassa: the effects of point mutations on the proteolipid portion of the mitochondrial ATP synthetase

Summary Five oligomycin-resistant (oli ^r) mutant strains of Neurospora crassa were analyzed for their growth rate and for the periodicity of their circadian rhythm. The most resistant strains had periods of 18–19 h while the least resistant strain had a normal period of 21.0 h. There was a rough correlation between the in vivo degree of oligomycinresistance and the amount of change in the period. Several of the oli ^r mutations have been previously described by Sebald et al. (1977) in terms of known amino acid changes in the primary structure of the proteolipid, or DCCD-binding protein, found in the F₀ membrane portion of the mitochondrial ATP synthetase. Amino acid changes in the structure of this protein are reported here for two other oli ^r mutations. The proteolipid isolation procedures were slightly modified to include a delipidation step, and an HPLC procedure was developed to separate the hydrophobic peptides of this protein. Analysis of heterocaryons carrying both the oli ^r and oli ^s markers indicated that the oli ^r and oli ^s mutations were codominant to each other in terms of period and growth rate. The changes in the primary structure of this DCCD-binding protein reported here are the first known examples of changes in the primary structure of a protein which alter the period of a circadian rhythm.