Genetic diversity and coefficient of parentage between clones and sugarcane varieties in Brazil.

The success of the development of new sugarcane varieties is associated with the ability to correctly select the genitor. The aim of this study was to evaluate the genetic diversity between 113 clones and sugarcane varieties using the Ward-modified location model procedure with added information about the coefficient of parentage and endogamy. In this study, data was used from 100 experiments that evaluated clones; the experimental phase was conducted in 70 places between the years 2002 and 2009 on the outlining in random blocks. According to the diversity analysis, 3 groups formed: G1, G2, and G3, which were composed of 58, 8, and 47 genotypes, respectively. The clones of groups G1 and G3 were the most outstanding. Thus, biparental crossbreeding involving clones and varieties of these 2 groups can efficiently obtain transgressive genotypes. Knowledge of the heterotypic groups indicated by the Ward-modified location model method, along with the parentage information, will make it a lot easier to define the desirable and undesirable crossbreeds for public and private breeding programs that develop sugarcane varieties.

Location of xylosyltransferase in the cisternae of the rough endoplasmic reticulum of embryonic cartilage cells.

Purified antibodies were prepared to UDP-D-xylose: core protein xylosyltransferase, the enzyme which initiates the formation of chondroitin sulfate chains in the course of proteoglycan biosynthesis in cartilage. The purified antibodies were conjugated to ferritin with a two-step glutaraldehyde procedure, and conjugates were then used to locate xylosyltransferase in fragments of embryonic cartilage cells. The results indicated that the enzyme is located within the cisternae of the rough endoplasmic reticulum. The distribution of the enzyme was similar to that of prolyl hydroxylase in the same cell fragments, suggesting that procollagen synthesis and initiation of chondroitin sulfate chains occur in the same regions of the rough endoplasmic reticulum.

Turnover of basic chromosomal proteins in fertilized eggs: a cytoimmunochemical study of events in vivo.

The chromosomal complements of mouse oocytes, ova, and fertilizing sperm have been studied by immunofluorescence with specific antisera to the basic protein fraction of sperm nuclei and to histones H2b and H4, and by staining with ethidium bromide. These studies support the hypothesis, previously proposed (Rodman and Barth, 1979, Dev. Biol. 68:82-95), that the chromosomes of the oocyte in maturation incorporate unique basic protein(s) similar to those incorporated during spermiogenesis. That similarity is characterized, here, by immunologic cross-reactivity. The basic proteins of the fertilizing sperm nucleus and the cross-reactive moiety of the two haploid complements of the ovum are displaced simultaneously, shortly after sperm entry. However, because the unique basic proteins incorporated into the oocyte chromosomes do not, as in the spermatogenic sequence, entirely replace the histones, the maternal chromosomes display histones H2b and H4 at all postfertilization stages examined, whereas the decondensing paternal complement, for an interval before maturation of the pronuclei, contains neither sperm basic chromosomal proteins nor histones. Sequential staining of the same specimens with ethidium bromide revealed well-organized nuclear morphology of the residual DNA complex. Those observations suggest that, for an as yet undefined period in the transformation from spermatozoal to embryonic genome, the chromatin is devoid of a complement of basic proteins.

Electrophoretic analysis of the stored histone pool in unfertilized sea urchin eggs: quantification and identification by antibody binding.

A maternal store of histones in unfertilized sea urchin eggs is demonstrated by two independent criteria. Stored histones are identified by their ability to assemble into chromatin of male pronuclei of fertilized sea urchin eggs in the absence of protein synthesis, suggesting a minimum of at least 25 haploid equivalents for each histone present and functional in the unfertilized egg. In addition, electrophoretic analysis of proteins from acid extracts of unfertilized whole eggs and enucleated merogons reveals protein spots comigrating with cleavage stage histone standards, though not with other histone variants found in later sea urchin development or in sperm. Quantification of the amount of protein per histone spot yields an estimate of several hundred haploid DNA equivalents per egg of stored histone. The identity of some of the putative histones was verified by a highly sensitive immunological technique, involving electrophoretic transfer of proteins from the two-dimensional polyacrylamide gels to nitrocellulose filters. Proteins in amounts less than 2 x 10(-4) micrograms can be detected by this method.

Segment-long-spacing aggregates and isolation of COOH-terminal peptides from type I procollagen.

Type I procollagen secreted by matrix-free cells from chick embryo tendons was purified by DEAE-cellulose chromatography. Electron microscopy of segment-long-spacing aggregates of the procollagen demonstrated the presence of both NH2-terminal and COOH-terminal extensions not found in collagen. The procollagen was digested with bacterial collagenase and the COOH-terminal fragments were isolated by gel filtration and polyacrylamide gel electrophoresis in sodium dodecyl sulfate. Analysis of tryptic peptides demonstrated that the COOH-terminal extensions on the pro alpha 1 and pro alpha 2 chains had different primary structures.

Mitochondrion of yeast: ultrastructural evidence for one giant, branched organelle per cell.

Three-dimensional models constructed from 80 to 150 consecutive serial sections of entire yeast cells showed that all the separate mitochondrial profiles were cross sections through a single, branching, tubular structure about 50 to 60 micrometers in length and 200 to 600 nanometers in diameter. The data are contrary to conventional notions of mitochondrial size, form, and number per cell and should lead to a reassessment of mitochondrial genetics and biogenesis.

Mesosomes in Pseudomonas aeruginosa.

The use of a combination fixative-staining procedure has allowed a detailed observation of mesosomes in thin sections of Pseudomonas aeruginosa.

Ultrastructural alterations associated with the growth of resistant Pseudomonas aeruginosa in the presence of benzalkonium chloride.

Cells of Pseudomonas aeruginosa resistant to benzalkonium chloride (BC) underwent unique ultrastructural reorganizations when they were grown in the presence of 1 mg of BC/ml. The resistant cells usually contained a single, centrally positioned pseudovacuole. The pseudovacuole was surrounded by a diffuse substance that spread irregularly throughout the cytoplasm. The presence of the pseudovacuole seemed to cause a physical compartmentalization of the cytoplasm into random pockets of ribosomes and nuclear material. Contained within the pseudovacuole was a horseshoe-shaped, electron-dense body which was bounded by a trilaminar membrane 5.2 nm in width. These bodies averaged 77 nm when measured through the long axis. The surfaces of resistant cells were covered by an additional layer not found in sensitive cells. Thin sections of sensitive cells which had been treated with 1 mg of BC/ml showed little or no lysis. The cytoplasm appeared to be deeply stained and coagulated. Ribosomes were no longer distinctly visible. Although the cell wall remained intact, the cell membrane was dissolved and fragmented. BC-grown resistant cells could not be successfully stained by standard techniques; however, details were demonstrated with the aid of a combination of 1.5% glutaraldehyde, 1% osmium tetroxide, and 1% phosphotungstic acid prepared in 0.1 m sodium dimethylarsonate buffer (pH 6.8).

Isolation of Intact Chloroplasts from Euglena gracilis by Zonal Centrifugation.

Chloroplasts were separated from Euglena gracilis by zonal centrifugation at low speed in density gradients of Ficoll or dextran. The chloroplasts were intact by the criteria of ultrastructure and their content of ribulose diphosphate carboxylase and soluble protein. The chloroplasts also contained ribosomes and ribosomal RNA uncontaminated by the corresponding cytoplasmic particles.

Cytochemical localization of catalase activity in yeast peroxisomes.

Diaminobenzidine oxidation product occurred in peroxisomes and in the intracristate spaces of mitochondria. The reaction was inhibited only in peroxisomes when 3-amino-1,2,4-triazole was present, but cyanide and azide inhibited deposition in both kinds of organelles.