Identification of somaclonal variants of sugarcane (Saccharum spp.) resistant to sugarcane mosaic virus via RAPD markers

Somaclonal variants resistant to sugarcane mosaic virus (SCMV) were obtained from susceptible sugarcane cv PR62258 through somatic embryogenesis by increasing the number of subcultures of the embryogenic callus tissue in MS medium with 3 mg/L 2,4-dichlorophenoxyacetic acid. Transfers were made at 30-day intervals for 1, 2 or 3 subcultures. Two somaclones, namely AT626 and BT627, were selected by their resistance to SCMV. These subclones have maintained the resistance trait over seven years of testing in the field. In this report we identified the somaclonal SCMV resistant variants from the maternal line and the nonresistant somaclones, using the RAPD technique.     

Noradrenergic and adrenergic systems in the brain of the urodele amphibian,Pleurodeles waltlii,as revealed by immunohistochemical methods

The distribution of noradrenaline and adrenaline in the brain of the urodele amphibian Pleurodeles waltlii has been studied with antibodies raised against noradrenaline and the enzymes dopamine--hydroxylase and phenylethanolamine-N-methyltransferase. Noradrenaline-containing cell bodies were found in the anterior preoptic area, the hypothalamic nucleus of the periventricular organ, the locus coeruleus and in the solitary tract/area postrema complex at the level of the obex. Noradrenergic fibers are widely distributed throughout the brain innervating particularly the ventrolateral forebrain, the medial amygdala, the lateral part of the posterior tubercle, the parabrachial region and the ventrolateral rhombencephalic tegmentum. Putative adrenergic cell bodies were found immediately rostral to the obex, ventral to the solitary tract. Whereas the cell bodies and their dendrites were Golgi-like stained, axons were more difficult to trace. Nevertheless, some weakly immunoreactive fibers could be traced to the basal forebrain. A comparison of these results with data previously obtained in anurans reveals not only several general features, but also some remarkable species differences.Abbreviations Acc Nucleus accumbens - AP area postrema - Apl amygdala, pars lateralis - Apm amygdala, pars medialis - ca commissura anterior - Cb cerebellum - cc central canal - Dp dorsal pallium - epl external plexiform layer - gl glomerular layer of the olfactory bulb - H ganglion habenulae - igl internal granular layer - Ip nucleus interpeduncularis - Lc locus coeruleus - Ll lateral line lobe - Lp lateral pallium - Ls lateral septum - ml mitral cell layer - Mp medial pallium - Ms medial septum - nPT nucleus pretectalis - NPv nucleus of the periventricular organ - nV nervus trigeminus - oc optic chiasm - Poa preoptic area - Ri nucleus reticularis inferior - SC nucleus suprachiasmaticus - sol solitary tract - Str striatum - thd thalamus dorsalis - thv thalamus ventralis - To tectum opticum - TP tuberculum posterius - V ventricle - VH ventral hypothalamic nucleus - III nucleus nervi oculomotorii - IXm nucleus motorius nervi glossopharyngei - Xm nucleus motorius nervi vagi     

Complex interaction between different proteinaceous components within the cell-wall structure ofCandida albicans

We have previously described a monoclonal antibody, MAb DC3:H10, which recognized an epitope preferentially expressed on the surface ofCandida albicans germ tubes. In the present study we examined the MAb-reactive material further. Immunoblot analysis of the material purified partially by Sephadex G-200 and DEAE-Sephacel chromatography reacted with antibodies to theC. albicans C3d receptor (CR2). In an ELISA, MAb DC3:H10 captured antigen that was recognized by both anti-CR2 and anti-mp58 fibrinogen binding mannoprotein polyclonal antibodies. The MAb DC3:H10 failed to compete with either of these antisera in an ELISA. Indirect immunofluo-rescence (IIF) analysis showed differences in surface distribution for the MAb DC3:H10, the CR2, and the mp 58 epitopes. Dual labeling IIF experiments showed MAb DC3:H10 binding to be unaffected by binding of fibrinogen or anti-mp58 antibody. However, the binding patterns of MAb DC3:H10 were modified in the presence of anti-CR2 antibody, suggesting a complex interaction between these cell wall components.     

The larval development of lateral musculature in gilthead sea bream Sparus aurata and sea bass Dicentrarchus labrax

Fibre-type differentiation of the lateral musculature has been studied in Sparus aurata (L.) and Dicentrarchus labrax (L.) during larval development. Histochemical and ultrastructural techniques show two presumptive muscle layers and two germinative zones of presumptive myoblasts. At hatching, myotomal muscle consists of a monolayer of thin undifferentiated cells near the skin (first germinative zone) overlying another mono-layer of small diameter fibres extending hypaxially and epaxially away from the transverse septum. Below this, there is a much thicker, deep layer of fibres, generally large in diameter and polygonal in shape. The presumptive myoblasts are located between these two layers of fibres in the second germinative zone. Initially, the superficial and deep muscle fibres show high and low myosin ATPase activity, respectively. Both layers grow by generating new fibres from the two mentioned germinative zones. At the end of larval life, the superficial layer changes its histochemical profile from high to low myosin ATPase activity and, at the same time, intermediate or pink muscle fibres can be observed by oxidative activity (the NADH-TR reaction). Morphometric analysis shows a significant increase in mean fibre diameter during successive ages, as shown by the Student's t-test (hypertrophic growth). Skewness and kurtosis values of fibre diameters point to the generation of a new fibre population from the germinative zones (hyperplastic growth).     

RS46(DXS548) genotyping of reproductive cells: approaching preimplantation testing of the fragile-X syndrome

In order to approach preimplantation testing for the fragile-X syndrome, we used genotyping of the polymorphic RS46(DXS548) locus closely linked to the FMR1 gene, in single reproductive cells of females. The RS46(DXS548) amplification was adjusted to the single cell level by a two-round polymerase chain reaction (PCR) procedure. Unfertilized oocytes and extruded polar bodies were subjected to PCR. RS46(DXS548) genotyping at the single cell level was successful in 95% of the samples. In two-third of the metaphase II oocytes and first polar bodies obtained from women who were heterozygous at the RS46(DXS548) locus, both maternal RS46(DXS548) alleles were observed because of crossing over during the first meiotic division. This makes gamete selection by first polar body analysis inefficient. From the allele frequencies found in 56 unrelated individuals, a heterozygote frequency of 51% was estimated, whereas the observed heterozygote frequency was 56%. The whole PCR procedure can be performed within 16 h after blastomere biopsy. Consequently, the selection and transfer of the diagnosed embryos can be carried out within an acceptable time. Therefore, preimplantation testing for the fragile-X syndrome with the RS46(DXS548) AC-repeat may be an alternative choice for prenatal testing for those carrier females who are heterozygous (informative) at the RS46(DXS548) locus.     

Isodicentric Y chromosome: cytogenetic,molecular and clinical studies and review of the literature

Dicentrics are among the most common structural abnormalities of the human Y chromosome. Predicting the phenotypic consequences of different duplications and deletions of dicentric Y chromosomes is usually complicated by varying degrees of mosaicism (45,X cell lines), which may, in some cases, remain undetected. Molecular studies in patients with dicentric Y chromosomes have been few, and only two studies have attempted to determine the presence of SRY (the putative testis-determining factor gene). We report an 18-year-old female with short stature, amenorrhea, hirsutism, hypoplastic labia minora, and clitoromegaly who has a 45,X/46,X,idic(Y)(p11.32)/47,X,idic(Y)(p11.32),idic(Y) (p11.32) karyotype. Southern analysis using Y-specific probes (Y97, 2D6, 1F5, pY3.4) and polymerase chain reaction (PCR) analysis using primers for ZFY and SRY were positive for all loci tested, indicating that almost all of the Y chromosome was present. Our findings and an extensive review of the literature emphasize the importance of molecular analyses of abnormal Y chromosomes before any general conclusions can be reached concerning the relative effects of the Y-chromosome abnormality and mosaicism on sexual differentiation.     

XY gonadal dysgenesis and gonadoblastoma: a study in two sisters with a cryptic deletion of the Y chromosome involving the SRY gene

This paper reports a case of XY gonadal dysgenesis in two sisters. Both patients presented an eunochoid female phenotype with normal external genitalia. At laparotomy, the elder sister was found to have bilateral gonadoblastoma. Cytogenetic studies, which included G and C banding and in situ hybridization, showed that the patients had an apparently normal 46, XY karyotype. PCR analyses revealed absence of the conserved portion (HMG box) of the SRY gene and of the Y chromosome pseudoautosomal boundary region sequence in both patients. The presence of the ZFY sequence was detected by Southern hybridization in the two affected sisters. The patients' father (46, XY, no mosaicism detected in peripheral blood lymphocytes) was positive for SRY and ZFY sequences. The occurrence of gonadoblastoma is discussed in terms of the genetic factors that may lead to tumor development.     

Dinucleotide repeat polymorphism at the D4S2458 locus close to the PKD2 locus on human chromosome 4q

A new polymorphic CA repeat sequence was identified within the candidate region fot the autosomal dominant polycystic kidney disease type 2 (PKD2) locus. It should be a useful marker in the localization of this gene.     

An autosomal dominant retinitis pigmentosa family with close linkage to D7S480 on 7q

Retinitis pigmentosa is the most prevalent inherited disorder of the retina. It can be autosomal dominant (adRP), autosomal recessive (arRP) or X-linked (XLRP). A form of adRP mapping to chromosome 7q was reported in a large Spanish pedigree. We have typed DNA from the members of another Spanish family for polymorphic markers from the known candidate genes. Positive lod scores were obtained only for the markers located on 7q31-35, giving a maximum lod score of 2.98 (3.01 by multipoint analysis) at = 0.00 for D7S480. A brief clinical evaluation is given.     

Influence of the culture medium on the expression of surface polypeptides of Yersinia enterocolitica

Three polypeptides (200, 46, and 25 kDal) encoded by the virulence plasmid were detected by SDS-PAGE in the outer membrane of Yersinia enterocolitica 09 grown at 37°C in brain-heart infusion medium. Bacteria grown at the same temperature in the tissue culture medium RPMI 1640 expressed five additional polypeptides (170, 135, 118, 100, and 98 kDal), but the 25-kDal band was not seen. The protein profile in RPMI 1640 resembles the expression pattern displayed by yersiniae when grown in vivo. The immunoblot of total membrane proteins of bacteria grown in brain-heart infusion medium revealed eight plasmid-encoded polypeptides, four of which were also in the outer membrane preparations, including a 28-kDal polypeptide. These peptides do not coincide with known plasmid-encoded outer membrane proteins.