Adrenergic regulation of ion transport by primary cultures of canine tracheal epithelium: Cellular electrophysiology

Summary We examined the effect of adrenergic agents on the cellular electrical properties of primary cultures of canine tracheal epithelium. Both isoproterenol and epinephrine stimulated Cl secretion, as evidenced by an increase in transepithelial voltage and a fall in transepithelial resistance. Moreover, both agents appear to increase the conductance of apical and basolateral membranes. However, the pattern of response was different. Isoproterenol initially depolarized apical voltage _a and decreased the fractional resistance of the apical membranef _R. These changes are consistent with an initial increase in apical Cl conductance. In contrast, epinephrine acutely hyperpolarized _a and increasedf _R, changes consistent with an initial increase in basolateral K conductance. Following the acute effect of epinephrine, _a depolarized andf _R decreased to values not significantly different from those observed with isoproterenol. The acute increase in basolateral K conductance produced by epinephrine appeared to result from stimulation of adrenergic receptors because it was reproduced by addition of the agonist phenylephrine, and blocked by the antagonist phentolamine. The ability of prazosin but not yohimbine to block the acute epinephrine-induced increase in K permeability indicates the presence of ₁ adrenergic receptors. The acute adrenergic-induced increase in basolateral K conductance may be mediated by an increase in cell Ca because the response was mimicked by addition of the Ca ionophore A23187. In contrast, the response to isoproterenol was similar to that observed with addition of 8-bromo-cAMP and theophylline. These results indicate that both and adrenergic agents mediate the ion transport processes in canine tracheal epithelium. adrenergic agents have their primary effect on the apical Cl conductance, probably via an increase in cAMP. adrenergic agents exert their primary effect on the basolateral K conductance, possibly via an increase in cell Ca.     

Regulation of guanylate cyclase activity by atrial natriuretic factor and protein kinase C

Summary The putative second messenger of certain atrial natriuretic factor (ANF) signal transductions is cyclic GMP. Recently, we purified a 180-kDa protein, apparently containing both ANF receptor and guanylate cyclase activities, and hypothesized that this is one of the cyclic GMP transmembrane signal transducers. The enzyme is ubiquitous and appears to be conserved. Utilizing the 180-kDa membrane guanylate cyclase, we now show that the 180-kDa guanylate cyclase is regulated in opposing fashions by two receptor signals—ANF stimulating it and protein kinase C inhibiting it. Furthermore, protein kinase C phosphorylates the 180-kDa enzyme. This suggests a novel switch on and switch off mechanism of the cyclic GMP signal transduction. Switch off represents the phosphorylation while switch on the dephosphorylation of the enzyme.     

How natural is a nature reserve?: an ideological study of British nature conservation landscapes

Areas set apart for nature conservation in Britain are broadly categorised according to their cultural purpose, and names are assigned to these in this paper. Nature reserves may be similar to zoos and botanic gardens in aiming to maintain the diversity of species and if so are termed biodiversity reserves. This tradition understands nature as a static collection of entities apart from humans. Maintaining traditional management at a site is arguably a good way to sustain species, it also retains old ways in which humans and nature were integrated in the life of the nation and so are called historic countryside parks. There is growing interest in wilderness areas, where nature is seen as primarily processes protected from human interference. Despite the strength of each of these, they suffer from attempting to restrict nature to a ghetto, a process that is economically and environmentally costly. Companion places are places which set sustainable examples of integrating human life and economic activity with maintaining biodiversity and offering an opportunity to encounter wild processes at the heart of life. The language of these four types, or vectors, of nature reserves is offered to help the discussion of our place in nature.     

Thiol modulation of TNFα and IL-1 induced MnSOD gene expression and activation of NF-κB

TNF and IL-1 each can activate NF-B and induce gene expression of manganese superoxide dismutase (MnSOD), a mitochondrial matrix enzyme which can provide critical protection against hyperoxic lung injury. The regulation of MnSOD gene expression is not well understood. Since redox status can modulate NF-B and potential B site(s) exist in the MnSOD promoter, the effect of thiols (including NAC, DTT and 2-ME) on TNF and IL-1 induced activation of NF-B and MnSOD gene expression was investigated. Activation of NF-kB and increased MnSOD expression were potentiated by thiol reducing agents. In contrast, thiol oxidizing or alkylating agents inhibited both NF-B activation and elevated MnSOD expression in response to TNF or IL-1. Since protease inhibitors TPCK and TLCK can inhibit NF-B activation, we also investigated the effect of these compounds on MnSOD expression and NF-B activation. TPCK and TLCK each inhibited MnSOD gene expression and NF-B activation. Since the MnSOD promoter also contains anAP-1 binding site, the effect of thiols and thiol modifying agents on AP-1 activation was investigated. Thiols had no consistent effect onAP-1 activation. Likewise, some of the thiol modifying compounds inhibited AP-1 activation by TNF or IL-1, whereas others did not. Since diverse agents had similar effects on activation of NF-B and MnSOD gene expression, we have demonstrated that activation of NF-B and MnSOD gene expression are closely associated and that reduced sulfhydryl groups are required for cytokine mediation of both processes.Abbreviations O₂ Superoxide radical - H₂O₂ Hydrogen peroxide - NAC N-acetyl L-cysteine - DTT Dithiothreitol - 2-ME 2-Mercaptoethanol - MnSOD Manganese superoxide dismutase - NF-B Nuclear factor kappa B - AP-1 Activator protein-1 - NBT Nitroblue tetrazolium - CAT Chloramphenicol acetyltransferase - TPCK N-tosyl-L-phenylalanine chloromethyl ketone - TLCK Na-p-tosyl-L-lysine chloromethyl ketone - TAME N--p-tosyl-L-arginine methyl ester - NEM N-ethyl maleimide - DEM Diethyl maleate - CDNB 1-chloro-2,4-dinitrobenzene - DTT_OX Oxidized dithiothreitol     

Differential location of regulatory and nonregulatory trehalases inCandida utilis cells

The isolation of vacuoles by density gradient centrifugation of protoplast lysates fromCandida utilis cells showed a high specific activity for nonregulatory trehalase in vacuoles whereas the regulatory trehalase activatable by phosphorylation behaves as a cytoplasmic enzyme. The vacuolar trehalase is a glycoprotein that can be precipitated by Con A-Sepharose. Treatment of this enzyme with endo H reduced its reactivity with the lectin without loss of enzyme activity and decreased its apparent molecular weight by gel filtration.Abbreviations cAMP adenosine 3, 5-cyclic monophosphate - Con A Concanavalin A - CP buffer 10mM sodium citrate-phosphate pH 6.8 - endo H endo--N-acetyl glucosaminidase H - PMSF phenyl-methyl-sulphonylfluoride - PNPG p-nitrophenyl--glucoside - PNPP p-nitrophenyl-phosphate     

Lectinochemical studies on the glyco-recognition factors of a <Emphasis Type="Bold">Tn</Emphasis> (GalNAc<Emphasis Type="Bold">α</Emphasis>1→Ser/Thr) specific lectin isolated from the seeds of <Emphasis Type="Italic">Salvia sclarea</Emphasis>

The lectin extracted from the seeds of Salvia sclarea (SSL) recognizes the Tn antigen (GalNAc 1Ser/Thr) expressed in certain human carcinomas. In previous studies, knowledge of the binding properties of SSL was restricted to GalNAc1 related oligosaccharides and glycopeptides. Thus, the requirements of functional groups in monosaccharide and high-density polyvalent carbohydrate structural units for SSL binding and an updated affinity profile were further evaluated by enzyme-linked lectinosorbent (ELLSA) and inhibition assays. Among the glycoproteins (gps) tested for interaction, a high density of exposed Tn-containing glycoproteins such as in the armadillo salivary Tn glycoprotein and asialo ovine salivary glycoprotein reacted best with SSL. When the gps were tested for inhibition of SSL binding, which was expressed as 50% nanogram inhibition, the high density polyvalent Tn present in macromolecules was the most potent inhibitor. Among the monosaccharide and carbohydrate structural units studied, which were expressed as nanomole inhibition, GalNAc 13GalNAc 13Gal 14Gal 14Glc (Fp), GalNAc 13Gal 14Glc (A_L), GalNAc 13GalNAc 1Me (F), GalNAc 13GalNAc 1Me (F ) and GalNAc 1 Ser/Thr (Tn) were the most active ligands, being 2.5–5.0× 10³ and 1.25–2.5 times more active than Gal and GalNAc, respectively. From the results, it is suggested that the combining site of SSL is a shallow groove type, recognizing the monosaccharide of GalNAc as the major binding site or Tn up to the Forssman pentasaccharide (Fp). It can be concluded that the three critical factors for SSL binding are the –NH CH₃CO at carbon-2 in Gal, the configuration of carbon-3 in GalNAc, and the polyvalent Tn (GalNAc 1Ser/Thr) present in macromolecules. These results should assist in understanding the glyco-recognition factors involved in carbohydrate–lectin interactions in biological processes. The effect of the polyvalent F , F and GalNAc 13Gal 1 (P ) glycotopes on binding should be examined. However, this is hampered by the lack of availability of suitable reagents.     

A quantitative method for separating reaction components of CMP-sialic acid: Lactosylceramide sialyltransferase using Sep Pak C18 cartridges

A rapid procedure is described for the separation of CMP-sialic acid:lactosylceramide sialyltransferase reaction components using Sep Pak C₁₈ cartridges. The quantitative separation of the more polar nucleotide sugar, CMP-sialic acid, and its free acid from the less polar G_M3-ganglioside is simple and rapid relative to previously described methods. Recovery of G_M3 is optimized by the addition of phosphatidylcholine to the reaction mixture prior to the chromatographic step. Using rat liver Golgi membranes as a source of CMP-sialic acid: lactosylceramide sialyltransferase activity (G_M3 synthase; ST-1), the transfer of [¹⁴C] sialic acid from CMP-[¹⁴C] sialic acid to lactosylceramide can be quantified by this assay. The procedure is reliable and may be applicable to the isolation of ganglioside products in otherin vitro glycosyltransferase assays.Abbreviations G_M3 G_M3-ganglioside - II³NeuAc-LacCer NeuAc2-3Gal1-4Glc1-1Cer - G_D1a G_D1a-ganglioside, IV³NeuAc, II³NeuAc-GgOse₄Cer, NeuAc2-3Gal1-3GalNac1-4(NeuAc2-3)Gal1-4Glc1-1Cer - G_D3 G_D3-ganglioside, II³(NeuAc)₂LacCer, NeuAc2-8NeuAc2-3Gal1-4Glc1-1Cer - GgOse₄Cer asialo-G_M1 Gal1-3GalNAc1-4Gal1-4Glc1-1Cer - FucG_MI fucosyl-G_MI-ganglioside, Fuc1-2Gal1-3GalNAc1-4Gal1-4 Glc1-1Cer - ST-1 G_M3 synthase, CMP-sialic acid:lactosylceramide sialyltransferase - LacCer lactosylceramide, Gal1-4Glc1-1Cer - CMP-NeuAc cytidine 5-monophospho-N-acetylneuraminic acid - PC phosphatidylcholine - PMSF phenylmethylsulfonyl fluoride     

Template-directed oligomerization of 5′-deoxy-5′-nucleosideacetic acid derivatives

5-Deoxy-5-nucleosideacetic acids II–V are isostructural analogues of nucleotides with a carboxylate group in the place of the 5-phosphate group. We have studied their oligomerization in aqueous solution using a water-soluble carbodiimide as the condensing agent in the presence or absence of an appropriate polynucleotide template. Condensation of adenylic acid analogues IIa, IIIa, and Va in the presence of polyuridylic acid were found to be the most efficient reactions. Cyclization of the activated monomers to lactones and the insolubility of the oligomers in aqueous solution were found to be obstacles to the efficient formation of long oligomers.     

Thidiazuron substitution for chilling requirement in three apple cultivars

Thidiazuron [(TDZ)N-phenyl-N-1,2,3-thidiazol-5-ylurea] at 750 M was applied to buds of apple trees to determine if it could substitute for the chilling requirement to induce bud break. Shoots of cv. Anna (low chill), Delicious cv. Redchief (medium chill), and Northern Spy (high chill) were untreated, treated with TDZ prior to chilling (before-chill), and treated with TDZ at various intervals after the accumulation of specific amounts of chilling (after-chill). Shoots were stored in a cold room at 4°C. TDZ applied prior to chilling reduced the chill unit (CU) requirement (1 CU = 1 h at 4°C) for the promotion of bud break on 1-year-old shoots of Anna and Northern Spy and 1- and 2-year-old wood of Delicious. TDZ applied after-chill promoted bud break only for Anna and buds on 2-year-old wood of Delicious. While accumulating CUs, untreated buds or buds treated with TDZ on 1-year Delicious and Northern Spy did not respond to the cold treatment even after 1848 h of CU accumulation. For all three cultivars, TDZ treatment was more effective in promoting bud break when applied before the initiation of chilling.The use of a company or product name does not constitute an endorsement by USDA or the University of Maryland nor imply approval to the exclusion of other suitable products.     

Ultrastructure of wheat seedling mitochondria under anoxia and postanoxia

Summary To characterize the cytoplasmic streaming in characean cells, tonoplast-free cells were prepared and the chemical composition of the cytoplasm was modified by intracellular perfusion. Perfusion media containing sulfate inhibited the cytoplasmic streaming. The extent of inhibition was dependent on the concentration of ATP: the lower the concentration of ATP, the stronger the inhibition. It was suggested that inhibition by sulfate is competitive with respect to ATP. The effects of other anions were also examined.Abbreviations ATP adenosine-5-triphosphate - [ATP] ATP concentration - ADP adenosine-5-diphosphate - EGTA ethylene glycolbis(-aminoethyl ether)-N,N,N,N-tetraacetic acid - MES 2-(N-morforino) ethanesulfonic acid - PEP phosphoenol pyruvate - Tris tris(hydroxymethyl) aminomethane - v velocity of cytoplasmic streaming     

The effect of some macronutrients on adventitious root development on scion apple cultivars in vitro

The influence of some macronutrients, especially NH₄NO₃ and KNO₃, on root development of microcuttings from 3 apple scion cultivars is discussed. A reduction of the level of NH₄NO₃ in the medium from full strength to 1/4 strength significantly increased the percentage rooting of Gala and Royal Gala, but not Jonagold. Further reduction of NH₄NO₃ level from 1/4 strength to zero significantly reduced the percentage of rooting in Gala but not Royal Gala. Jonagold rooted best at zero concentration NH₄NO₃. Without NH₄NO₃, rooting percentages were as high as 100% for all 3 cultivars when KNO₃ was provided at full strength. The results show that adventitious roots can be induced on apple scion cultivars by media manipulation.     

Glycosphingolipids of leukocytes are unbranched at the galactopyranosyl residue and contain fucosylα-1-3-N-acetylglucosamine structures

Glycolipids of peripheral leukocytes which had been used for the production of interferon were separated into oligoglycosylceramides, polyglycosylceramides and polyglycosylpeptides (erythroglycan). Neutral oligoglycosylceramides comprised glucosylceramide, galactosylceramide, lactosylceramide, lactotriaosylceramide, globotriaosylceramide andneolactotetraosylceramide. Globotetraosylceramide was not detected. Glycolipids which were more complex thanneolactotetraosylceramide belonged exclusively to theneolacto series of compounds and were essentially unbranched at galactopyranosyl residues. The polyglycosylceramide fraction contained a glycolipid with a probable structure Gal1-4(Fuc1-3) GlcNAc1-3Gal1-4GlcNAc1-3 Gal1-4GlcNAc1-3Gal1-4Glc1-1ceramide. Polyglycosylpeptides were found only in trace amounts and were also unbranched at galactopyranosyl residues. All glycoconjugates studies did not contain significant amounts of carbohydrate structures derived from ABH immunodominant groups.Nomenclature Gal1-4Gal1-4GlcCer Lactotrioasylcermide (LcOse₃Cer) - Gal1-4Gal1-4GlcCer globotriaosylceramide, (GbOse₄Cer) - GalNAc1-3Gal1-4 Gal1-4GlcCer globoside (globotetraosylceramide, GbOse₄Cer) - Gal1-4GlcNAc1-3Gal1-4GlcCer paragloboside (lacto-N-neo tetraosylceramide,nLcOse₄Cer)     

A simple brassinolide analogue 2α, 3α-dihydroxy-17β-(3-methyl-butyryloxy)-7-oxa-B-homo-5α-androstan-6-one which induces bean second internode splitting

A new synthetic brassinolide analogue, 2,3-dihydroxy-17-(3-methylbutyryloxy)-7-oxa-B-homo-5-androstan-6-one (11), has been shown to exhibit typical brassinolide activity characterised by elongation, swelling, twisting and splitting of the bean second internode. It was prepared from the known lactone 2,3,17-trihydroxy-7-oxa-B-homo-5-androstan-6-one (4) which was transformed to an isopropylidenedioxy derivative. After protection of the 2- and 3-hydroxy groups it yielded the 2,3-isopropylidenedioxy-17-(3-methyl-butyryloxy)-7-oxa-B-homo-5-androstan-6-one (7) on treating with 3-methylbutyryl chloride in pyridine. The analogue with a 2-methylbutyric moiety (10, 2,3-dihydroxy-17-(2-methyl-butyryloxy)-7-oxa-B-homo-5-androstan-6-one) in position 17 stimulated only elongation and swelling of the bean second internode. However, in this bioassay 100 times more 10 or 11 compared to 24-epibrassinolide is required to obtain the same effects. Analogues with -oriented hydroxyl groups at C-2 and C-3 (14,15), a 6-ketone (17,18) or 6-oxa-7-oxo-lactone system (12,13) in ring B lack the typical brassinolide activity. In addition, the active brassinosteroids applied to the second internode stimulated a similar, but 30% lower elongation of the first internode. From data presented here we conclude that the presence of two hydroxy groups in the positions 22 and 23 of the brassinolide side chain, which are considered as a key structural requirement, is not absolutely necessary for a compound to exhibit typical brassinosteroid activity. Nevertheless, these compounds have generally 2–10 times lower activity than that having 22,23-vicinal diol in the side chain.     

Aflatoxin influences on seed germination and root elongation by two cultivars of Glycine max and uptake of 65 Zn-ZnCl2 by the cultivars

Maximum inhibition of Glycine max, cv. Essex seed germination occurred at 10 g/ml following 72 hr imbibition in constant light. Seeds imbided 108 hr in constant darkness at this concentration showed a 20% rise in germination over that of the control. Imbibition of G. max, cv. Williams seeds in either light or dark for 96 hr did not suppress germination. Imbibition of Essex seeds in either light or dark at 2.5 through 10 g/ml stimulated root elongation except for 10 g/ml at 96 hr (light). Maximum inhibition of Williams root elongation under constant light was at 48 and 72 hr with 10 g/ml. Statistically significant differences in cotyledon, leaf and stem lengths between non-treated (NT) and treated (T) seedlings were not found except for Williams stem length at 2.5 / ml. Root elongation was stimulated 1.2- and 1.1-folds, respectively, at 5.0 (Essex) and 2.5 (Williams) g/ml. Toxin at 2.5 through 10.0 g/ml did not markedly alter either cotyledon or leaf widths with the exception of Williams leaf width at 2.5 g/ml. Medium supplementation with 2.5 through 10.0 g/ml resulted in cotyledon, leaf and root weight enhancements for Essex seedlings. Stem weight was not markedly affected. An 18% rise in Williams cotyledon weight above that of the control was seen at 2.5 g/ml. Williams leaf weights were increased 1.75- and 1.25-folds, respectively, at 2.5 and 10.0 g/ml. Aflatoxin B₁, at 2.5 g/ml promoted Williams stem and root elongation 1.20- and 1.09-folds, respectively. Most of the radioactivity from ⁶⁵Zn-ZnCl₂ recovered within organs was found within Essex roots for both T and NT seedlings. A higher amount of radioactivity was recovered within roots at each toxin concentration than was without toxin. However, this was not statistically significant. Significant differences in the distribution of radioactivity within roots between NT and T Williams seedlings were not observed. Generally, AFB₁ failed to affect significantly these two varieties of soybeans based on the tests relating to germination, growth and radiolabel uptake.     

Endogenous abscisic acid and 2-trans-abscisic acid in alternate bearing ‘Wilking’ mandarin trees

The relationship of abscisic acid (ABA) and 2-trans-abscisic acid (t-ABA) to alternate bearing has been examined in Wilking mandarin (Citrus reticulata Blanco) trees. Leaves, stems and buds of trees loaded with fruit (on trees) had 4.3, 6.0 and 2.2 fold higher ABA levels than the corresponding organs from off trees. Leaves had higher ABA levels than stems and buds in both on and off trees. t-ABA was non-detectable in Wilking leaf, stem and bud tissue. Amounts of t-ABA not exceeding 40% of the ABA content, were found in Shamouti and Valencia orange buds and in Wilking fruit peel.The elevated levels of ABA in on tree organs may reflect a stress imposed by the fruit overload.     

Regio- and stereo-selective synthesis of vinyl glucose ester catalyzed by an alkaline protease of Bacillus subtilis

The transesterification of -d-glucose with divinylsuccinate, divinyladipate and divinylsebacate in pyridine at 55 °C for 3 days was catalyzed by an alkaline protease from Bacillus subtilis to give corresponding 6-O-vinyl glucose esters at 30%, 53% and 35% yield, respectively. The stereo-selectivity of the alkaline protease toward the -anomer was affected by the acyl donor chain length. 6-O-Vinylsuccinyl-d-glucose was mixture of - and -anomers (/=44/56), the other two products were the pure -d-glucose derivatives.     

Growth of rose flower peduncles and effects of applied plant growth regulators

Removal of flower buds results in abscission of peduncles of the rose cv. Nubia and cessation of peduncle growth in cv. Mercedes. Peduncle growth was inhibited when pistils and stamens were removed, but was not affected by removal only of sepals and petals. Growth of the decapitated peduncles of Mercedes was partially restored by the application of auxin in lanolin paste on the base of the peduncle and was completely restored by the application of gibberellin, while the combined application of auxin and gibberellin was the most effective for growth restoration. Growth of non-decapitated Nubia peduncles was promoted by application of gibberellin or gibberellin and auxin but not auxin alone.Peduncle elongation of both cultivars was not affected by application of cytokinin and the effect of gibberellin was antagonized by combined application with cytokinin. The peduncles strength (resistance to bending) was affected more strongly by auxin than by gibberellin, and most strongly when auxin and gibberellin were combined. The effect of auxin on the strength of peduncles, but not of gibberellin, was antagonized by application of cytokinin. Excised, non-decapitated flowering stems of Nubia treated with gibberellin and auxin in situ, showed, recovery of the peduncles from wilting after exposure to heat conditions.     

Bacteriophage ?29 DNA replication in vitro: Participation of the terminal protein and the gene 2 product in elongation

Summary From 29-infected Bacillus subtilis cells, we have isolated a protein fraction which promotes in vitro replication of 29 DNA. This fraction catalyses both initiation and elongation, indicating that it contains the product of gene 3 (tp: terminal protein) and the product of gene 2 (gp2: probably a DNA polymerase), since initiation requires the two products (Blanco et al. 1983; Matsumoto et al. 1983). The fractions isolated from cells infected with temperature-sensitive (ts) mutants of gene 2 and gene 3 were thermolabile in both the initiation and elongation assays. When the pre-initiated material from the ts fractions of each mutant was heat-inactivated and mixed no complementation, restoring the elongation activity, was found. These results indicate: (i) tp and gp2 participate not only in the initiation but also in the elongation of 29 DNA replication, (ii) they probably function in tight physical association with each other.Abbreviations gp2 product of gene 2 - tp terminal protein - DNAtp DNA with terminal protein covalently linked at both the 5 ends - ddCTP 2,3-dideoxycytidine 5-triphosphate - ddGTP 2,3-dideoxyguanosine 5 triphosphate     

High-level Expression of Maize <Emphasis Type="Italic">γ</Emphasis>-zein Protein in Transgenic Soybean (<Emphasis Type="Italic">Glycine max</Emphasis>)

Primers were developed for 118 microsatellites isolated from grape (Vitis vinifera) genomic libraries enriched for (AC)n repeats. Only one microsatellite sequence matched other grape SSR-sequences in the GeneBank database. Genotyping was carried out in the parental lines and four offspring of two pseudo-test-cross populations, Cabernet Sauvignon x Seyval and Chardonnay x Bianca, and a further six other grape genotypes (V. vinifera Sultanina, Merlot, Syrah, Müller-Thurgau, Vitis Regent and V. riparia Gloire de Montpellier). A total of 108 microsatellites showed easily scorable alleles and 100 of them segregated according to a configuration suitable for mapping in either cross. A further 8 SSRs, although unsuitable for mapping in those crosses, showed polymorphism in the other genotypes tested. This set of markers was used, along with 75 microsatellites of other repeat-types, to fingerprint 46 offspring of the cross Chardonnay x Bianca. For each full-sib, individual heterozygosity and distance in repeat units between pairs of alleles at each locus (mean d²) were calculated as a tool for predicting highly outbred recombinant individuals. Six microsatellites with segregation ratios significantly distorted towards the lack of homozygous sibs were identified and mapped to linkage groups LG 3 and LG 5. Estimation of heterozygosity at genome-wide level and genotyping at loci for which homozygous sibs are discriminated against are discussed for marker-assisted background selection in outcrossing grapevines.     

The beta chorionic gonadotropin-beta luteinizing gene cluster maps to human chromosome 19

Summary We used a cloned human cDNA probe homologous to the placenta chorionic gonadotropin subunit (CGB) and to the pituitary luteinizing hormone subunit (LHB) and Southern blotting techniques to analyse DNA from a series of rodent x human somatic cell hybrids for the presence of specific gonadotropin subunit related sequences. Our results provide evidence for the assignment and linkage of the eight genes (or pseudogenes) coding for the subunit of these glycoprotein hormones to chromosome 19. Moreover, we observed a strict concordance between the permissivity of mouse x man hybrid cells to enteroviruses (which is linked to the presence of specific cell receptors encoded by human chromosome 19) and the presence of CGB and LHB related sequences, thus confirming the localization of the structural genes for the subunits on chromosome 19.This work was supported in part by INSERM grants CRL 81 1041 and by MRC grant MT 4860