Trisomics from triploid-diploid crosses in self-incompatible Lycopersicum peruvianum

Summary An attempt was carried out to produce trisomics of the wild tomato L. peruvianum, to define their essential features, and to detect relationships between trisomy and the expression of self-compatibility.Triploid-diploid crosses in L. peruvianum yielded nearly 40% aneuploids. Of these, 18% were single trisomics, and the rest had 2, 3 and 4 extra chromosomes. Almost all the trisomics occurred in crosses where the triploid was used as female parent. Vigour and fertility of trisomics were not much different from those of disomics, and morphologically they were very similar.The extra chromosome was identified in three self-compatible trisomic plants through somatic and pachytene chromosome morphology. One of these plants was trisomic for chromosome 1, while the other two were trisomic for chromosome 3. In these trisomics a positive correlation was found between chromosome length and trivalent formation, but no relationship between chromosome length and frequency of laggards was observed.A series of test-crosses revealed that the capacity of the trisomics to produce seed upon selfing always resulted from alterations of the incompatibility phenotype of the style and not from competitive interaction in the pollen. Progeny analyses showed that the self-compatibility features of the trisomics were not transmitted from one generation to the next. The implications of these findings are discussed.This work has been supported by a contract between the European Communities and the CNEN. This publication is contribution no. 1458 from the Biology Division of the European Communities and contribution no. 472 from the Divisione Applicazioni delle Radiazioni del CNEN.     

Different responses of CR(−) and CR(+) B cells to LPS stimulation

Proliferative response of B cells with or without CR [CR(+) or CR(?) B cells] was compared in their polyclonal response when they were stimulated with lipopolysaccharide (LPS). CR(+) B cells responded better in proliferation and more poorly in polyclonal antibody formation than did CR(?) B cells. The dissociation between proliferation and antibody formation in LPS response was not due to the shift of the time kinetics nor the exhaustion of the culture medium. T cells and macrophages did not take part in the dissociation, since macrophage depletion from nu/nu mouse spleen cells could not modify the dissociation. The polyclonal antibody response of CR(?) B cells was more resistant to irradiation than that of CR(+) B cells. These results suggest that among LPS-responsive B cells there are CR(?) B-cell subset(s) more mature than CR(+) B cells.     

碳量子点对模式植物拟南芥的生物效应研究

以模式植物拟南芥（Arabidopsis thaliana（L.）Heynh）为材料,从生理及分子层面研究碳量子点（Carbon quantum dots,CQDs）对拟南芥生物效应的影响。结果显示,CQDs能被拟南芥根部吸收并连续运输到叶片,对种子萌发率无明显影响,但能显著促进幼苗主根伸长和株重的增加。幼苗叶片叶绿体中色素含量随CQDs浓度的升高而显著降低。脯氨酸与丙二醛含量随CQDs浓度的升高呈先上升后下降趋势。超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性随CQDs浓度的升高呈先上升后下降趋势,在抗氧化酶系统中起主导作用;叶片内源过氧化氢（H₂O₂）的积累随CQDs浓度的升高而升高,具有显著的浓度依赖效应。与其他纳米材料处理不一样的是,硫同化及胁迫相关基因在CQDs处理后表达量下调,这可能与CQDs粒子本身的特性有关。     

Insulin-like growth factors, IGF-1, IGF-2 and somatomedin C trigger cell proliferation in mammalian epithelial cells cultured in a serum-free medium

A single insulin-like growth factor which constitutes part of a defined serum-free medium is sufficient to stimulate DNA synthesis and mitosis in mammalian lens epithelial cells. Rabbit lenses were cultured in KEI-4, a medium which mimics rabbit aqueous humor, or in KEI-4 containing insulin growth factor I (IGF I), insulin growth factor II (IGF II) or somatomedin C. The magnitude of DNA synthesis and mitosis was evaluated on whole mount preparations of the epithelium at various times of culture. IGF I and II, the most highly purified of the insulin-like growth factors, and somatomedin C were equipotent lens mitogens, were active at the ng level, were more mitogenic toward lens epithelial cells than insulin, and initiated cell proliferation throughout the normally amitotic central region of the lens epithelium. The time course of the mitotic response elicited by the insulin-like growth factors was identical to that noted in lenses cultured in medium supplemented with serum or insulin. The present results, coupled with those of other investigators, suggest that insulin-like factors may regulate cell division in the mammalian lens in vivo.     

生物群落的生态稳定性

1.生物群落生态稳定的概念从生态学意义看,生物群落是稳定的,就是指它在相当长的一段时间内保持其中各种群数目不变,意即一方面,任何一个种群的数量不会少到能繁衍后代,乃致绝灭,另一     

[B10,22-Asp,B25-Tyr-NH2]-去β链C端五肽胰岛素的合成和性质

本文报道了[B10,22-Asp,B25-Tyr-NH2]-去B链羧端五肽胰岛素的制备及其生物活性。结果表明,这一类似物的生物活力比去五肽胰岛素(DPI)的活力高一倍,但却比Gerald所报道的[B10-Asp,B25-Tyr-NH_2]-DPI的活力低很多,说明后者的高活性可能依赖于分子中B22-Arg的存在。     

Statistical assessment of population variability: a methodological approach

We have implemented a multivariate statistical methodology to assess the degree and pattern of cranial variability in skeletal samples. Specifically, the method is designed to test whether variability in a skeletal sample exceeds "normal within-group variability" defined in the present instance as variability present among crania from a cemetery associated with a village. It involves comparing a covariance matrix derived from a sample of unknown composition to one representing "normal within-group variability." The method has been applied to two Plains Indian craniometric samples. The Leavenworth site (39CO9) represents the remnants of previously autonomous Arikara Indian villages devastated by epidemic diseases in the late 1700s. The Bad River 2 Phase is an archaeological designation grouping together closely related sites in the Bad-Cheyenne region of South Dakota dating from 1740-1795 AD. We were able to show substantial heterogeneity among crania from Leavenworth. District burial areas at Leavenworth account for some of the heterogeneity, supporting the notion that they represent an attempt to maintain former social distinctions. We were unable to differentiate among sites within the Bad River 2 Phase, suggesting that it is a valid biological unit.     

Evidence for the occurrence of two forms of β-lipotropin in rat pituitary

A peptide isolated from porcine gut according to its glucagon-like activity in liver (bioactive enteroglucagon) has been characterized immunologically, biologically and chemically: its potency relative to pancreatic glucagon in interacting with an antiglucagon antibody, hepatic glucagon-binding sites and hepatic adenylate cyclase was ～100%, 20% and 10%, respectively. In contrast, it is ～20-times more potent than glucagon in oxyntic glands, justifying the term ‘oxyntomodulin’. Chemically, it consists in the 29 amino acid-peptide glucagon elongated at its C-terminal end by the octapeptide Lys—Arg—Asn—Lys—Asn—Asn—Ile &;—Ala; accordingly, it is called ‘glucagon-37’     

Number of alleles at the incompatibility loci in Secale cereale L.

Summary Two experiments were performed to estimate the number of alleles at the two incompatibility loci of rye in the variety Halo. In one experiment I₁ progenies from enforced selfing under controlled conditions were isolated. In the other experiment a genotype, homozygous at both incompatibility loci, was used as pollinator for a sample of the Halo population, which was regarded as an equilibrium population. Genotypes, which are homozygous at both incompatibility loci, can be found after selfing. The estimate for the number of alleles was 6 to 7 at one locus and 12 to 13 at the other locus.     

Purification of the prothoracicotropic hormone from the tobacco hornworm Manducasexta

Standard biochemical procedures were used to purify the prothoracicotropic hormone (PTTH) 4400 fold from whole head extracts of $\text{Mandura}$$\text{sexta}$ fifth instar larvae. Hormonal activity was bioassayed by injection into neck-ligated fourth instar larvae. The hormone was stable to heating at 85°C. Ammonium sulfate and acetone fractionation provided a crude preparation which showed dose-dependent activity in the bioassay. Chromatography on Sephadex G-100, DEAE-Sephadex, and hydroxylapatite gave a preparation with 2.6 $\text{Manduca}$ PTTH units/μg protein (4400-fold purification). Activity was sensitive to proteolytic enzymes. Further purification by preparative electrophoresis gave a preparation which migrated as a single band in two polyacrylamide gel electrophoresis systems. A molecular weight estimate of 25,000 Daltons was obtained for this bands on SDS polyacrylamide gels.