Sprouting Resistance and Falling Number Values in Introgressive Triticale/T. Monococcum Lines

The aim of this work was to evaluate how the Falling Number (FN) in introgressive triticale lines is influenced by introduced Triticum monococcum genes responsive for mature spikes sprouting resistance (SR). These lines were developed in two independent series (A and B) by incorporating of diploid wheat (T. monococcum) genes in two different strains of hexaploid triticale (LT 176/10 and LT 522/6) using the synthetic allotetraploid T. monococcum/Secale cereale (A^mA^mRR) as a bridging form. In three consecutive vegetation seasons the mature spikes response to artificial wetting was tested to assess SR. FN was evaluated in full milling of seeds to characterize the level of starch-protein matrix damage in 57 introgressive triticale lines. The obtained results showed twofold higher coefficients of variation of the SR than FN. SR-FN correlation was generally significant in a B-series of lines and statistically insignificant in an A-series showing dependence on the triticale recipient parent and year. In opposite to SR, in both series there was not a line having FN comparable with that of diploid wheat parent. This demonstrates that genetic background of the FN is more complicated in relation to inheritance of SR. This revised version was published online in July 2006 with corrections to the Cover Date.     

An ultrastructural study of microsporogenesis in tobacco line SR1

This article provides an ultrastructural atlas of microsporogenesis in the tobacco model line SR1. The stages of cell-wall remodeling and reorganization of the intercellular channels, accompanying this process, are reported for the microspore mother cells. The meiotic changes in the cell nucleus and cytoplasm are traced. The appearance of single-, double-, or multi-membrane nuclear vacuoles in microspore mother cells and their further elimination from the nucleus are for the first time described for the genus Nicotiana as well as deviations from a normal course for this process. Intercellular chromatin migration (cytomixis) was observed in the microsporogenesis of the line SR1 and behavior of the nuclear vacuoles within the cytomictic nucleus was described for the first time. The enzymatic activity of spherosome-like vesicles in the tobacco microsporogenesis is discussed. The features of microsporogenesis in the tobacco line SR1 are compared with those of other plant species and its association with the transition from a diploid to a haploid phase of the life cycle is discussed.     

Streptomycin resistance is inherited as a recessive Mendelian trait in a Nicotiana sylvestris line

Summary The SR180 cell line has been isolated in a callus culture derived from a haploid Nicotiana sylvestris (n = X = 12) plant by its ability to proliferate on a selective medium containing 2,000 g/ml streptomycin sulphate. From the cell line diploid plants have been regenerated. The SR180 selfs are resistant to streptomycin. Streptomycin sensitivity in F1, and a 31 (sensitive to resistant) segregation in F2 indicate that resistance in the SR180 mutant is the result of a recessive Mendelian mutation.     

Chromosome studies of the cultured cells of two species of side-necked turtles (Podocnemis unifilis and P. expansa)

The diploid chromosome number of two species of sidenecked turtles (Podocnemis unifilis and P. expansa) was found to be 28. Under normal culture conditions, half of the chromosomes of P. unifilis consistently show one or two clear secondary constrictions. In P. expansa, the incidence of cells with chromosomes bearing secondary constrictions and the number of such chromosomes per cell are less. Cells of two P. unifilis cell lines maintained a normal diploid karyotype for two years following their initiation. Then one cell line shifted to a hypodiploid mode of 27 and half of the population of the second line became pseudodiploid, the other half remaining diploid. A single six-month-old cell line from P. expansa has maintained a normal diploid mode through 10 passages.Supported in part by grant-CA 08737 from the National Cancer Institute.     

The presence of the enhanced K/Na discrimination trait in diploid Triticum species

Summary A number of accessions of the three species of diploid wheat, Triticum boeoticum, T. monococcum, and T. urartu, were grown in 50 mol m^-3 NaCl+2.5 mol m^-3 CaCl₂. Sodium accumulation in the leaves was low and potassium concentrations remained high. This was not the case in T. durum grown under the same conditions, and indicates the presence in diploid wheats of the enhanced K/Na discrimination character which has previously been found in Aegilops squarrosa and hexaploid wheat. None of the accessions of diploid wheat showed poor K/Na discrimination, which suggests that if the A genome of modern tetraploid wheats was derived from a diploid Triticum species, then the enhanced K/Na discrimination character became altered after the formation of the original allopolyploid. Another possibility is that a diploid wheat that did not have the enhanced K/Na discrimination character was involved in the hybridization event which produced tetraploid wheat, and that this diploid is now extinct or has not yet been discovered.     

<Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated <Emphasis Type="Italic">in planta</Emphasis> transformation of maize germ cells

A transfer DNA (T-DNA) carrying the marker gene nptII was detected in the genomes of diploid and haploid maize plants obtained after the treatment of pistil filaments with a suspension of Agrobacterium during artificial pollination. PCR analysis of total DNA isolated from 155 canamycin-resistant diploid F1 seedlings revealed T-DNA insertions in the genomes of 111 plants (32.7% of the total number of analyzed seeds). The example of matroclinal haploids was used to demonstrate that T-DNA may be transported to the egg cell by the growing pollen tube (PT). Twelve out of 16 analyzed haploid plants contained the T-DNA insertion. The possible mechanism of the transfer of the Agrobacterium T-DNA to the maize genome during pollination is discussed.     

Chromosome changes in methotrexate-resistant cell lines of Drosophila melanogaster

Cells resistant to methotrexate (MTX) were obtained from two established cell lines of D. melanogaster and a karyological analysis was performed. No conspicuous changes in the frequencies of cell types were observed in MTX-resistant (MTX^R) subline 0.57, as compared with the original line, whose cells were mostly near-tetraploid. On the contrary, altered karyotypes were frequently noticed in the C1 82 MTX^R subline, as compared with the original line, whose cells were mostly diploid. The C1 82 MTX^R subline was characterized by mostly tetraploid cells and by the presence of chromosome fragments (in 48% of them). The mitotic segregation suggests the presence of a centromere in these fragments and the fluorescence pattern, after quinacrine staining, suggests that they may be derivatives of the X chromosome.     

Mapping of the gene Nxphu that controls hypersensitive resistance to potato virus X in Solanum phureja IvP35

 The line IvP35 of the diploid (2n=2x=24) cultivated potato species Solanum phureja (family Solanaceae) expresses hypersensitive resistance (H) to potato X potexvirus (PVX). In this study, a diploid potato population was produced using IvP35 as the male parent and a diploid line of S. tuberosum (87HW13.7) as the female parent and tested for resistance to PVX. Data indicated that H to PVX in IvP35 is a dominant, monogenically inherited trait controlled by a single gene, named Nx _phu , that is in a simplex condition (Nxnx). RFLP analysis carried out on the progeny lines revealed 4 markers (CT220, TG328, CT112 and TG424) from the long arm of chromosome IX that were linked to the hypersensitive phenotype; the closest linkage was observed with the marker TG424. Previous authors have shown that the same region of chromosome IX contains the gene Sw-5 for resistance to tomato spotted wilt tospovirus in Lycopersicon peruvianum (Solanaceae). Received: 18 September 1997 / Accepted: 24 November 1997     

Establishment of the diploid gynogenetic hybrid clonal line of red crucian carp × common carp

This study investigated the gynogenetic cytobiological behavior of the third gynogenetic generation (G3), which was generated from the diploid eggs produced by the second gynogenetic generation (G2) of red crucian carp × common carp, and determined the chromosomal numbers of G3, G2×scatter scale carp and G2×allotetraploid hybrids of red crucian carp × common carp. The results showed that the diploid eggs of G2 with 100 chromosomes, activated by UV-irradiated sperm from scatter scale carp and without the treatment for doubling the chromosomes, could develop into G3 with 100 chromosomes. Similar to the first and second gynogenetic generations (G1 and G2), G3 was also diploid (2n=100) and presented the hybrid traits. The triploids (3n=150) and tetraploids (4n=200) were produced by crossing G2 with scatter scale carp and crossing G2 with allotetraploids, respectively. The extrusion of the second polar body in the eggs of G2 ruled out the possibility that the retention of the second polar body led to the formation of the diploid eggs. In addition, we discussed the mechanism of the formation of the diploid eggs generated by G2. The establishment of the diploid gynogenesis clonal line (G1, G2 and G3) provided the evidence that the diploid eggs were able to develop into a new diploid hybrid clonal line by gynogenesis. By producing the diploid eggs as a unique reproductive way, the diploid gyno- genetic progeny of allotetraploid hybrids of red crucian carp × common carp had important signifi- cances in both biological evolution and production application.     

Acute inhibitory effect of alpha‐mangostin on sarcoplasmic reticulum calcium‐ATPase and myocardial relaxation

The benefits of α‐mangostin for various tissues have been reported, but its effect on the heart has not been clarified. This study aimed to evaluate the effects of α‐mangostin on cardiac function. Using a cardiac sarcoplasmic reticulum (SR) membrane preparation, α‐mangostin inhibited SR Ca²⁺‐ATPase activity in a dose‐dependent manner (IC₅₀ of 6.47 ± 0.7 μM). Its suppressive effect was specific to SR Ca²⁺‐ATPase but not to myofibrillar Ca²⁺‐ATPase. Using isolated cardiomyocytes, 50 μM of α‐mangostin significantly increased the duration of cell relengthening and increased the duration of Ca²⁺ transient decay, suggesting altered myocyte relaxation. The relaxation effect of α‐mangostin was also supported in vivo after intravenous infusion. A significant suppression of both peak pressure and rate of ventricular relaxation (–dP/dt) relative to DMSO infusion was observed. The results from the present study demonstrated that α‐mangostin exerts specific inhibitory action on SR Ca²⁺‐ATPase activity, leading to myocardial relaxation dysfunction.     

Genetic depletion reveals an essential role for an SR protein splicing factor in vertebrate cells

SR proteins are essential for the splicing of messenger RNA precursors in vitro, where they also alter splice site selection in a concentration-dependent manner. Although experiments involving overexpression or dominant mutations have confirmed that these proteins can influence RNA processing decisions in vivo, similar results with loss-of-function mutations have been lacking. Now, a system for genetic depletion of the chicken B cell line DT40 has revealed that the SR protein ASF/SF2 (alternative splicing factor/splicing factor 2) is essential for viability in these cells⁽¹⁾. This study opens the way for a complete functional dissection of this protein, and other SR proteins, in vivo.     

New Heterothallic species of Hansenula

Summary As the genusHansenula is at present constituted,H. fabianii appears to be the first species of its phylogenetic line to have become independent of trees and bark beetles. It is also the last species of its line to occur in nature with the haploid, or basic, number of chromosomes. So near is it to the diploid level of evolution that a sporulation medium rich in malt extract favors the development of diploid vegetative cells in the period between conjugation of opposite sexes and the onset of sporulation. The diploid form is easily isolated from the mixture and, as long as sporulation is prevented, may be kept in pure state. Media that favor vegetative development of the species favor its occurrence as haploid vegetative cell.H. fabianii is most closely related toHansenula subpelliculosa Bedford, which occurs in nature as the diploid form. Both species have been isolated almost exclusively as contaminants of fermentations, and both have been used industrially in Oriental fermentations to make alcoholic beverages or foods.This is a laboratory of the Northern Utilization Research and Development Division, Agricultural Research Service, U.S. Department of Agriculture.     

Establishment and characterization of two embryonic cell lines of <Emphasis Type="Italic">Bombyx mori</Emphasis>

Two cell lines, i.e., BmE-SWU1 and BmE-SWU2, were established from silkworm embryonic tissues of the reversion phase through primary culture in Grace’s medium supplemented with 20% fetal bovine serum. The BmE-SWU1 cell line mainly included diploid spindle cells and round cells, which were large and had severe heteroploidy karyotypes. The population doubling time of the 30th passage of the cell line was 58.7 hr. BmE-SWU2 cells were oblong or round, and small. The population doubling time for the 30th passage of the cell line was 46.6 hr. Of BmE-SWU2 cells 89.9% were diploid (2n = 56). Both strains were attached to epithelial-like cell lines and were susceptible to Bombyx mori nucleopolyhedroviruse (BmNPV). Inter simple sequence repeat (ISSR) fingerprinting of silkworm embryonic cell line was obtained.     

Ca-ATPase activity and protein composition of sarcoplasmic reticulum membranes isolated from skeletal muscles of typical hibernator,the ground squirrel Spermophilus undulatus

Ca-ATPase activity in sarcoplasmic reticulum (SR) membranes isolated from skeletal muscles of the typical hibernator, the ground squirrel Spermophilus undulatus, is about 2-fold lower than that in SR membranes of rats and rabbits and is further decreased 2-fold during hibernation. The use of carbocyanine anionic dye Stains-All has revealed that Ca-binding proteins of SR membranes, histidine-rich Ca-binding protein and sarcalumenin, in ground squirrel, rat, and rabbit SR have different electrophoretic mobility corresponding to apparent molecular masses 165, 155, and 170 kDa and 130, 145, and 160 kDa, respectively; the electrophoretic mobility of calsequestrin (63 kDa) is the same in all preparations. The content of these Ca-binding proteins in SR membranes of the ground squirrels is decreased 3–4 fold and the content of 55, 30, and 22 kDa proteins is significantly increased during hibernation.     

The expression of maternally-transmitted sex ratio condition (SR) in two strains ofDrosophila melanogaster

A study was made ofwillistoni-SR infections, transmitted for many generations through the maternal line, in two wild-type strains ofD. melanogaster. As in the species of origin, the SR agent is essentially lethal only to males. The twomelanogaster strains differ from each other in the time required for the effects of SR to be expressed, both in terms of the first appearance of SR broods and in the developmental stages at which death of males occurs. Host genotype within a species is thus an important factor in the expression of SR. Host age and breeding temperature are also of consequence in determining the degree to which SR is expressed. In any given instance, the specific expression of SR is determined by complex interactions between host, SR agent, and the environment.     

Content of histone H1 and histone phosphorylation in relation to the higher order structures of chromatin in Drosophila

The amount of histone H1 relative to core histones has been determined in three Drosophila species (D. melanogaster, D. texana and D. virilis) in chromatin from several tissues differing in chromatin structure and genetic activity. Low levels of H1 were found in relatively undifferentiated, early embryos as well as in a line of cultured cells. In late embryos the content of H1 was highest in D. virilis which possesses larger amounts of and a partially more compacted constitutive heterochromatin than the two other species. Polytene chromatin from larval salivary glands showed increased levels of H1 compared with diploid chromatin and the degree of phosphorylation of this histone was relatively low. The degree of phosphorylation of H2A was found to be drastically reduced in polytene as compared with diploid embryonic chromatin, which parallels the extensive underreplication of constitutive heterochromatin. Also, in diploid chromatin a qualitative correlation was observed between the relative amounts of heterochromatin and the levels of H2A phosphorylation. These findings suggest a connection between H2A phosphorylation and heavy compaction of interphase chromatin.     

A stable, “near-haploid” mammalian cell line (Dipodomys ordii)

An established SV40-transformed cell line of Dipodomys ordii was cloned for selective loss of chromosomal material. A clone is described which has a modal chromosome number of 50 (in the normal diploid 2n=72), and has about 66% of the DNA content of normal diploid cells. Karyotype analysis shows that, although some chromosome rearrangement has taken place, 23 chromosomes are completely unpaired and 7 chromosomes are partially unpaired. Buoyant density analysis in neutral CsCl and Cs₂SO₄+Ag gradients of the DNA of this clone shows that there has been no selective retention or loss of any of the satellite DNA components present in D. ordii during the elimination of 34% of the genetic material.     

Male mating performance and cytoplasmic incompatibility in a wPip Wolbachia trans‐infected line of Aedes albopictus (Stegomyia albopicta)

Wolbachia pipientis Hertig (Rickettsiales: Rickettsiaceae) is a maternally inherited endosymbiont of a large number of insects and other arthropods that induces various effects on host reproductive biology. Among these, cytoplasmic incompatibility (CI) is a form of sterility induced in eggs produced by mating between infected males and females uninfected or infected by an incompatible Wolbachia strain. This phenomenon has been proposed as a potential way to produce functionally sterile males to be used in genetic control programmes. In this paper, we report on experiments carried out to evaluate the mating performances of males of an Aedes albopictus (Stegomyia albopicta) (Diptera: Culicidae) line (ARwP), harbouring a new Wolbachia infection [the wPip strain from Culex pipiens Linnaeus (Diptera: Culicidae)], in comparison with naturally infected males (SR line). ARwP males did not differ from SR males with regard to insemination capacity. Mating competitiveness did not differ significantly between lines in either laboratory or greenhouse conditions. Moreover, crosses with SR females were characterized by a 100% CI regardless of ARwP male age. All of these findings suggest that ARwP males may represent a very efficient tool for control programmes against Ae. albopictus based on the release of functionally sterile males.     

SR 140333, a Novel, Selective, and Potent Nonpeptide Antagonist of the NK1 Tachykinin Receptor: Characterization on the U373MG Cell Line

The effects of a novel nonpeptide NK1 tachy-kinin receptor antagonist, SR 140333, on the functional consequences of NK1 receptor activation in a human astrocytoma cell line, U373MG, were investigated. Radioligand binding conducted with ¹²⁵l-Bolton-Hunter substance P revealed a competitive inhibition by SR 140333 and its R enantiomer SR 140603 with K_i values of 0.74 and 7.40 nM, respectively. The NK1-selective agonist, [Sar⁹,Met(O₂)¹¹]-substance P, stimulated the formation of inositol phosphates with an EC₅₀ of 3.8 × 10^?9M. SR 140333 blocked the stimulatory effect of this agonist (10^?7M) with an IC₅₀ of 1.6 × 10^?9M,whereas the effect of another NK1 agonist, septide (EC₅₀= 1.5 × 10^?8M)was antagonized with an IC₅₀ of 2.1 × 10^?10M.Enhancement of [³H]taurine release by [Sar⁹,Met(O₂)¹¹]-substance P (EC₅₀= 7.4 × 10^?9M) was also inhibited by SR 140333 with an IC₅₀ of 1.8 × 10^?9 M. SR 140603 was 10-fold less potent than SR 140333 in inhibiting inositol monophosphate formation and [³H]taurine release. The calcium mobilization induced by [Sar⁹,Met(O₂)¹¹]-substance P (10^?8M) was totally prevented by 10^?8MSR 140333. Patchclamp experiments showed that SR 140333 depressed the outward current evoked by 5 × 10^?8M [Sar⁹, Met(O₂)¹¹]-substance P with an IC₅₀ of 1.3 × 10^?9M. The expression of c-fos was stimulated by [Sar⁹,Met(O₂)¹¹]-substance P with an EC₅₀ of 2.5 × 10^?10M, an effect that was also inhibited by SR 140333 with an IC₅₀ of 1.1 × 10^?9M. The present results illustrate the sequential events of the response elicited by NK1 agonists, which were antagonized by SR 140333, demonstrating its powerful NK1 antagonist activity on a functional basis.     

Mode of hybridogenesis and habitat preferences influence population composition of water frogs (Pelophylax esculentus complex,Anura: Ranidae) in a region of sympatric occurrence (western Slovakia)

Coexistence of sperm‐dependent asexual hybrids with their sexual progenitors depends on genetic and ecological interactions between sexual and asexual forms. In this study, we investigate genotypic composition, modes of hybridogenetic gametogenesis and habitat preferences of European water frogs (Pelophylax esculentus complex) in a region of sympatric occurrence. Pelophylax esculentus complex comprises parental species P. ridibundus and P. lessonae, whose primary hybridization leads to hybridogenetic lineages of P. esculentus. Hybrids clonally transmit one parental genome and mate with the other parental species, forming a new generation of hybrids. In the region of western Slovakia, we found syntopic occurrence of diploid and triploid hybrids with P. lessonae, syntopic occurrence of all three taxa as well as the existence of pure P. ridibundus populations. All triploid hybrids were exclusively male possessing one ridibundus and two different lessonae genomes (RLL). Sex ratio in diploid hybrids was substantially female‐biased. Irrespective of the population composition, diploid hybrids excluded the lessonae genome from their germ line and produced ridibundus gametes. Contrarily, RLL males unequivocally eliminated the ridibundus genome and produced diploid lessonae sperms. Perpetuation of RLL males in studied populations is most likely achieved by their mating with diploid hybrid females. The composition of water frog populations is also shaped by taxon‐specific habitat preferences. While P. ridibundus preferred larger water bodies (gravelpits, fishery ponds, dead river arms), P. lessonae was most frequently found in marshes and smaller sandpits. Pelophylax esculentus occupied predominately similar habitats as its sexual host P. lessonae.