普通烟草和黄花烟草及体细胞杂种过氧化物酶同工酶等电聚焦电泳

日本学者长尾照义(1978)用原生质体融合获得普通烟草与黄花烟草的体细胞杂种植株。1980年陈家玉等在国内首先获得普通烟草(Copus Yeusuku No.4)和黄花烟草(Yellow Flower)的体细胞杂种植株。之后,中国农科院烟草所(1981)也得到相同的结果。陈家玉等(1983)对上述杂种进行了形态学、细胞学和同工酶的分析并取得一定的结果。Dlineee等(1975)分析比较了用等电聚焦技术分离的过氧     

Hybridization of Gossypium species through in ovulo embryo culture

An interspecific hybrid of the sexually incompatible species G. hirsutum cv. Laxmi and G. arboreum cv. Jyoti was obtained through in ovulo embryo culture. Eightto twelve-day-old ovules were excised and cultured on Beasley and Ting's medium supplemented with Indol-3 acetic acid (5×10^-6 to 7×10^-6 M), Kinetin (5×10^-6 to 5×10^-8 M), Gibberellic acid (5×10^-7 to 5×10^-9M), Ammonium chloride (5 to 15mM) and Casein hydrolysate (50 to 200mg/l) added individually and in various combinations along with sucrose. No single medium was adequate to ensure complete development of the fertilized ovules to plantlets, thus necessitating a sequential five step transfer to different media. Cytological studies confirmed the hybrid nature of the plants.Abbreviation IAA Indol-3 acetic acid - Kn Kinetin - GA₃ Gibberellic acid - CH Casein hydrolysate - NAA -Naphthalene-acetic acid - BT Beasley and Ting's basal medium - MS Murashige and Skoog's basal medium - W White's basal medium NCL Communication number 3823.     

Irreversible Activation of the Opiate Receptor of Neuroblastoma × Glioma Hybrid Cells by an Alkylating Benzomorphan Derivative

The benozomorphan derivative (-)-2-[2-(p-bromoacetamidophenyl)ethyl]-5,9 alpha-dimethyl-2'-hydroxy-6,7-benzomorphan (BAB), capable of reacting with nucleophilic groups, acts on neuroblastoma X glioma hybrid cells as a potent, irreversible opiate agonist. Its potency in inhibiting the increase in cellular cyclic AMP, evoked by prostaglandin E1, is comparable to that of Leu-enkephalin. This also applies to its capacity to compete with [3H]D-Ala2-Met-enkephalinamide ([3H]DAEA) in binding on cell membrane preparations. The comparatively lower potency of (-)-2-[2-(p-acetamidophenyl)-ethyl]-5,9 alpha-dimethly-2'-hydroxy-5,7-benzomorphan (AB), which differs from BAB in the substitution of the bromoacetamido group by an acetamido group, is of the same order of magnitude as that of morphine. The covalent interaction of BAB with the opiate receptors is deduced from the observations that (1) it is not possible to wash away this compound from the receptors, (2) the potency of BAB in inhibiting the specific binding of [3H]DAEA increases with prolonged preincubation time, and (3) AB behaves as a reversible agonist.     

Electrophoretic analysis of a chromosomal hybrid zone in the grasshopper Podisma pedestris

We have made an extensive allozyme survey of 21 enzyme and protein loci in populations of the alpine grasshopper Podisma pedestris. This species occurs in two races, differing by a chromosomal fusion which separates the ancestral XO/XX race from a derived neo-XY race. These races also differ in DNA content, and hybrids between them have reduced viability. Electrophoresis reveals that the amount of genetic differentiation between these races is no greater than the variation among populations within each race. Both larger-scale surveys and a detailed survey of an area where the races hybridize, show that the chromosomal change is not correlated with gene frequency changes at any of the 21 loci studied. These findings are consistent with recently developed theory concerning the strength of the barrier to gene flow posed by a hybrid zone with characteristics such as those measured experimentally in Podisma. It is argued that hybrid zones in other species which involve allozymic differences do so because of stronger selection against hybrids rather than through mating isolation.     

The carotenoid pigments in the juice and flavedo of a mandarin hybrid (Citrus reticulata) cv michal during ripening

The carotenoid pigments ofthe mandarin hybrid (Citrus reticulata) cv Michal, in the juice and flavedo were characterized at three ripening stages, before, during and after colour break. During ripening the characteristic mandarin pattern was formed in the juice, which contained cryptoxanthin as the principal pigment. In the flavedo the chloroplast carotenoid pattern of the green fruit changed into the characteristic pattern of C. reticulata with a high level of citraurin which, together with cryptoxanthin, imparts an intensive reddish tint to the hybrid. The flavedo contained an unusual C₃₀ apocarotenoid, β-citraurinene (8′-apo-β-caroten-3-ol). The flavedo carotenoids of this accidental hybrid were compared with the carotenoids of the presumed parents Dancy tangerine and Clementine. The hybrid resembles more the second parent, from which it inherited the ability to biosynthesize a higher amount of citraurin as well as citraurinene. Citraurinene, considered a Citrus hybrid-specific pigment, was found for the first time in a Citrus variety. A possible biosynthetic pathway of the Citrus C₃₀ -apocarotenoids is proposed.     

Resistance of Some Vitis Rootstocks to Xiphinema index

Thirty-eight grapevine (Vitis spp.) rootstocks were screened in pots for resistance to the dagger nematode, Xiphinema index, from 1979 to 1981. Resistance ratings were based on visible root symptoms and on changes in the nematode populations over 16 months. Nineteen of the 23 Californian hybrid rootstocks tested were resistant, as were ''Harmony'','' ''Freedom,'' ''Schwarzmann,'' and ''3309.'' Two hybrids of V. rufotomentosa, ''171-52'' and ''176-9,'' were possibly immune to X. index. The rootstocks ''ARG 1,'' '' 110 R,'' ''1202,'' and ''1616,'' which are used commercially for phylloxera resistance were susceptible.     

A high level of hybrid dysgenesis in Drosophila: High thermosensitivity, dependence on DNA repair, and incomplete cytotype regulation

Summary An unusually high level of P-M hybrid dysgenesis in Drosophila melanogaster is characteristic of hybrid offspring originating from both, A (M × ) and B (P × M) crosses of a subline of the Harwich P strain, termed H ^s . The novel properties induced by mobility of P elements carried by H ^s paternal chromosomes include: very high (over 95%) gonadal dysgenesis (GD) in both sexes at the low restrictive temperature of 21°C, and highly premature sterility when males are reared at 18°C and aged at 21°C. Although all three major chromosomes of the H ^s subline contributed to this atypical pattern of gonadal dysgenesis, chromosome 3 had the largest effect. Gonadal dysgenesis showed a temperature- and sex-dependent repression pattern by the defective P elements of Muller-5 Birmingham chromosomes; at 21°C there was virtually no repression of male sterility, but most effective repression of GD in females. At 29°C repression was effective in males, but declined in females. The high thermosensitive sterility, low fecundity, and premature aging of the male germ line were greatly exacerbated when males derived from either A or B crosses were deficient either in excision repair (mei-9 mutation) or in post-replication repair (mei-41 mutation). These findings demonstrate that both DNA repair pathways are essential for the repair of lesions induced by P element transposition and support the hypothesis that P element-induced chromosome breaks are responsible for the virtual abolition of the germ line. The relatively high premature sterility of cross B DNA repair-deficient males, reared at 18°C and aged at 21°C, indicates that there is incomplete cytotype regulation in H ^s subline hybrids.     

Testicular development and serum sex steroid profiles during the annual sexual cycle of the male sturgeon hybrid the bester

Testicular development in the adult male F₁ sturgeon hybrid, the bester ( Huso huso L. female x Acipenser ruthenus L. male), was examined monthly in relation to serum sex steroid levels. Spermatogenesis lasted for 1 year, with meiosis generally starting in September and spermiogenesis in November, although there was considerable variation in testicular developmental stages between fish sampled monthly. Testicular development continued, slowly, during the winter months until April. Fish did not exhibit spontaneous spermiation, and phagocytotic activity of Sertoli cells became prominent from May onwards. Androgen levels increased during Spermatogenesis and remained high throughout the pre-spermiation period. In the degeneration stage, 11-ketotestosterone concentrations declined to low levels, while testoster- one levels remained high. The serum concentration of 17,20β-dihydroxy-4-pregnen-3-one was low throughout the reproductive cycle. Based on these results, it is suggested that the time appropriate for induction of final maturation would be from November–December to April when the testes are in the late stage of development.     

Non-reciprocal cross-incompatibility in Trichogramma deion

In non-reciprocal cross-incompatibility (NRCI), the crossing of a female of a strain A with a male of a strain B results in hybrid offspring, whereas the reciprocal cross produces few or no hybrids. Only females are of hybrid origin in Hymenoptera because they arise from fertilized eggs; males arise from unfertilized (haploid) eggs. Crosses between many strains of Trichogramma deion showed some degree of NRCI. Crosses between a T. deion culture collected in Seven Pines, California (SVP) with one from Marysville, California (MRY) showed an extreme form of NRCI in which practically no female offspring was produced when MRY females were crossed with SVP males. The reciprocal cross produced a close to normal proportion of female and male offspring. Detailed studied of this cross indicated that 1) the female offspring produced in the compatible interstrain cross were not the result of parthenogenesis but were true hybrids, 2) the incompatible interstrain cross did not produce female offspring because fertilized eggs died during development, 3) the death of these eggs could not be prevented by either antibiotic or temperature treatment, 4) cytoplasmically inherited factors causing NRCI could be discounted because backcrossed females with the genome of MRY and the cytoplasm of SVP, exhibit the NRCI relationship characteristic of their genome. Therefore the NRCI between these strains appears to be caused by a modification coded for by the nuclear genes of MRY that results in incompatibility when SVP sperm fertilizes MRY eggs. In addition the level of incompatibility in crosses between the SVP females and MRY males is temperature sensitive, the higher the rearing temperature the lower the level of compatibility.