葡萄果实发育过程中果肉细胞超微结构的观察

用透射电镜观察了“巨峰”葡萄(Vitis vinifera×V.labrusca)果实3个发育时期中果肉细胞超微结构的变化。果实第一次快速生长期的果肉细胞超微结构表现出物质和能量代谢旺盛的特点。缓慢生长期的果实虽外部形态平静少变,但果肉细胞超微结构表现出深刻的变化:细胞核形状特化为裂瓣状是最显著的特点;线粒体数目丰富;粗面内质网槽库膨大形成的囊泡富集,出现向液泡汇融和向质膜靠近的现象;质膜内陷;液泡膜完整。另外,原生质也出现一些降解的现象。但总体结构特点表明果肉细胞在此期处于十分活跃的物质周转代谢和信息交换过程中。果实第二次快速生长期果肉细胞超微结构表现出衰老降解的特点,但线粒体结构依然完整,数量仍然丰富,原生质膜也保持了很好的完整性,这似乎与维持第二次快速生长或成熟有关。     

“Gene-fouled or gene-improved?” Media framing of GM crops and food in Hungary

This paper presents results from a research which analyzed the reporting on genetically modified crops and food in the Hungarian tabloids and political papers with the highest circulation from 1 May 2007 to 31 October 2009. Both quantitative and qualitative media analysis was conducted. It was found that in contrast to some Western countries the issue had low salience in the investigated period; it featured especially marginally in the tabloids. Two distinct valenced frames could be differentiated: a dominant ANTI-GM (Threat) frame – which was particularly frequent compared to what has been found for some other countries, and a minority PRO-GM (Advancement and Benefits) frame. Despite a range of similarities with what had been reported by previous research from some other countries, argumentation on the GMO topic in the Hungarian press had several distinct characteristics, one of which was the relative prominence of economic arguments against the technology.     

Parallel and nonparallel aspects of ecological, phenotypic, and genetic divergence across replicate population pairs of lake and stream stickleback

Parallel (or convergent) evolution provides strong evidence for a deterministic role of natural selection: similar phenotypes evolve when independent populations colonize similar environments. In reality, however, independent populations in similar environments always show some differences: some nonparallel evolution is present. It is therefore important to explicitly quantify the parallel and nonparallel aspects of trait variation, and to investigate the ecological and genetic explanations for each. We performed such an analysis for threespine stickleback (Gasterosteus aculeatus) populations inhabiting lake and stream habitats in six independent watersheds. Morphological traits differed in the degree to which lake-stream divergence was parallel across watersheds. Some aspects of this variation were correlated with ecological variables related to diet, presumably reflecting the strength and specifics of divergent selection. Furthermore, a genetic scan revealed some markers that diverged between lakes and streams in many of the watersheds and some that diverged in only a few watersheds. Moreover, some of the lake-stream divergence in genetic markers was associated within some of the lake-stream divergence in morphological traits. Our results suggest that parallel evolution, and deviations from it, are primarily the result of natural selection, which corresponds in only some respects to the dichotomous habitat classifications frequently used in such studies.     

Experimental oil exposure of Ascophyllum nodosum (L.) Le Jolis

The effect of weathered, crude oil on Ascophyllum nodosum was tested in an outdoor experiment and in a laboratory experiment. Adult A. nodosum plants which were exposed to oil in an outdoor basin for 3 days showed reduced growth for a certain period of time, after which growth recovered. Also, some necrotic damage was observed. Three-week-old and 1-year-old germlings placed under the adult plants showed no significant reduction in number compared to control plants. In the laboratory experiment some of the 1-month-old germlings were initially exposed to oil for 6 min, some for 1 h, some for 3 h and some for 5 h. After 3 weeks in running, filtered water oil-exposed germlings had reached the same length as those in the control groups, and no effect of exposing the germlings to oil for different lengths of time at the start of the experiment was found. The results indicate that a limited oil pollution of weathered, crude oil may reduce growth and biomass of adult plants for a certain period of time. However, this need not be detrimental to a population with good recruitment from germlings or vegetative shoots growing under a dense canopy layer.     

Freeze-fracture studies on barley plastid membranes. VII. Structural changes associated with phosphorylation of the light-harvesting complex

Chloroplast thylakoid membranes were isolated from barley at room temperature under redox conditions which ensured that the light-harvesting complex was either non-phosphorylated or phosphorylated. The ultrastructural appearance of these membranes was characterised by rotary shadowed, freeze-fracture electron microscopy. Upon phosphorylation, there was a slight (5%) decrease in the extent of thylakoid stacking, as evidenced by an increase in EFu face particle density. It was concluded from detailed measurements of particle density and size distribution that phosphorylation of the light-harvesting complex results in the movement of some of the Photosystem II EFs particles and some of the PFs particles containing the light-harvesting complex from grana to stroma membranes. There was also a slight increase in PFs particle size and the appearance of a population of large particles on this face, which may be due to conformational changes in the light-harvesting complex or to the movement of some Photosystem I particles from stroma to grana membranes.     

The development of the pattern of innervation in chicken hindlimb muscles: evidence for specification of nerve-muscle connections

The pattern of innervation in 13 chicken hindlimb muscles was studied at various stages of development in order to examine the mechanisms which regulate its formation. The pattern of innervation was visualized by examining the distribution of fiber types within each muscle. It was found that the fiber type which a myotube acquired was influenced by both its time of formation and its position within a muscle. The earliest generation of myotubes (primary) had a marked tendency to become type I fibers, whereas, in contrast, the later generation of myotubes (secondary) tended to differentiate into type II fibers. There were regions of muscle, however, in which primary myotubes differentiated into type II fibers and other regions in which secondary myotubes acquired type I characteristics. During the development of some muscles the pattern of fiber types changed as a result of either a selective loss of type I fibers or, in other cases, a rearrangement of some of the initial neuromuscular contacts. These observations are consistent with the pattern of innervation of a muscle being established as a result of differential projection patterns of fast and slow motoneurons and the existence of some type of chemoaffinity where particular myotubes are preferentially innervated by particular motoneurons.     

The genetics of self-incompatibility in Brassica campestris L. ssp. Oleifera Metzg. II. Genotypic and environmental modification of S locus control

Continuous variation in the expression of self-incompatibility, from complete self-incompatibility to self-compatibility, was observed among plants of the spring turnip rape cultivar Arlo. Significance of the variation between inbred progenies of plants from the base population suggested that a polygenic system had some influence on the expression of self-compatibility. The responses to one generation of selection within some of these progenies supported this conclusion. Further evidence of the operation of some polygenic modifying complex was provided by an analysis of a diallel cross among seven of the inbred lines. The analysis detected significant additive genetic variation among the parental lines, considerable non-allelic interaction and some dominance of an ambi-directional type.Significant seasonal variation in the expression of self-compatibility was observed in Arlo, the level of self-compatibility being substantially higher in summer than in winter. Under controlled environments, an increase in temperature from 25°C to 30°C resulted in a significant increase in the level of self-compatibility. The extent to which self-compatibility was affected by temperature differed among lines which were homozygous for a specific S allele.     

长穗偃麦草DNA导入小麦后代变异系醇溶蛋白的研究

应用花粉管通道技术,将抗逆性强的长穗偃麦草总ＤＮＡ导入普通小麦甘麦８号,后代中出现了广泛的变异,并筛选出两个高产、分蘖力强、抗条锈病的新品系。以这两个品系为材料,以供体和受体作为对照,研究了外源ＤＮＡ导入后籽粒醇溶蛋白的变化,发现醇溶蛋白的增加、缺失和电泳迁移率的变化,新增加的组分与供体长穗偃麦草某些组分相对应。由此推测外源ＤＮＡ导入受体后有可能某些ＤＮＡ片段插入受体基因组从而导致受体基因表达改变或基因突变。     

Inhibition of the UV induction of sister-chromatid exchanges in ICR-2A frog cells by pretreatment with gamma-rays

Nuclear toxicity of several known carcinogens and fecal fractions obtained from 10 healthy individuals was investigated in the colonic nuclear aberration (NA) assay using an intrarectal administration. Two known colon carcinogens, MNNG and DMAB, and a carcinogen of organs other than the colon, B(a)P, induced NA in a dose-related manner. Chromatographic fractions of feces from 10 donors were tested for their ability to produce NA. The dichloromethane fraction for several was active and yielded a significantly positive response which was dose-related. Our study demonstrated that the feces of some healthy individuals contain compound(s) which damage colonic nuclei in a similar manner to that seen with some known carcinogens.     

Identification of amino acid sequences that can function as translocators of β-lactamase in Escherichia coli

A plasmid vector, pYZ1, was constructed which lacks most of the beta-lactamase signal-peptide coding region, but has a unique EcoRI site spanning codons 2 and 3 of the resultant cytoplasmic beta-lactamase derivative. Short quasi-random DNA sequences were cloned into the EcoRI site and Escherichia coli transformants in which some translocation of beta-lactamase across the cytoplasmic membrane was restored were selected by their ability to survive and form colonies on plates containing a low level of ampicillin. About 15-20% of all in-frame inserts restored some beta-lactamase translocation and the salient feature of these sequences was their marked hydrophobicity. These results are discussed in the light of a similar study in which sequences able to function as translocators of invertase in yeast were cloned and analysed (Kaiser et al., 1987).     

Some principles in the organization of sigma70-specific promoters on the E. coli genome on the basis of electrostatic patterns of promoter DNA

The distribution of electrostatic potential of the complete sequence of the E. coli genome was calculated. It was found that DNA is not a uniformly charged molecule. There are some local inhomogeneities in its electrostatic profile, which correlate with the position of promoters in the genome. Electrostatic patterns of promoter DNAs can be specified due to the presence of some distinctive motifs, which may be involved as promoter signal elements in RNA-polymerase-promoter recognition.     

A reappraisal of the terverticillate penicillia using biochemical, physiological and morphological features. III. An evaluation of pectinase and amylase isoenzymes for species characterization

Polyacrylamide gel electrophoresis of extracellular pectinase and amylase isozymes of 170 mainly terverticillate Penicillium strains was undertaken. The data were coded and subjected to numerical analysis. Variation in intensity of isozymes was observed in repeat analyses of some strains, although most were consistent. Variation was also observed between some representative strains of species. P. viridicatum was more variable than P. brevicompactum and P. hordei for intensity of pectinase activity. There was a correlation between the grouping of the strains on the basis of the isozymes and the species concepts only in some cases. The method proved useful for the identification of strains producing intense activity which provided clear patterns, for example, P. brevicompactum and P. chrysogenum and to a lesser extent P. solitum var. crustosum and P. hordei. The method was also exclusionary in that some species were restricted to a particular cluster or subcluster. Amylase patterns confirmed that strains referred to as single species are not all homogeneous genetically, and that some strains are not simply haploid homokaryons. The genetic heterogeneity of the strains explains some of the problems in the systematics of the terverticillate penicillia.     

Selection for Mating Reluctance in Females of a Diploid Parthenogenetic Strain of DROSOPHILA MERCATORUM

A diploid parthenogenetic strain of Drosophila mercatorum was outcrossed to produce genetic variance among the impaternate female offspring. Selection experiments were carried out for reluctance of the parthenogenetic females to mate.After only two cycles of selection, a parthenogenetic strain which is significantly less receptive to males from three different bisexual strains was obtained. It was also found that there is some degree of sexual isolation among the three bisexual strains used. The results support the idea that selection can render a newly produced diploid parthenogenetic strain behaviorally different from its bisexual ancestor. This appears to provide a framework which can explain the natural coexistence of diploid bisexual and diploid parthenogenetic biotypes in some species of insects.     

Isolation and characterization of Pediococcus halophilus from salted anchovies (Engraulis anchoita)

The presence of bacteria in salted anchovies during and at the end of the curing process was investigated. Attempts to isolate bacteria under aerobic or anaerobic conditions led to the isolation of only bacteria of the genus Pediococcus which were identified as Pediococcus halophilus. The isolates correspond to a rather heterogeneous group in which some of the members differ in some biochemical tests from the types described in the literature.     

树鼩应激镇痛的研究

用辐射热和电刺激两种方法测定了应激状态下树鼩(Tupaia belangeri chinensis)的痛反应值。结果表明,在应激状态下,树鼩的痛反应值在1—7分钟内下降了100—200％。上述结果提示,树鼩的痛反应降低与应激镇痛有关。     

Some remarks on the clinical characteristics,infectiousness and treatment of dermatycoses caused by Trichophyton rubrum

The object of this report was to draw the attention of the dermatological public to the present-day variability of the clinical pictures produced byTrichophyton rubrum and to new findings which help to explain some of the more severe forms. Its purpose is also to remind the reader that local therapy, which has unwarrantedly been underestimated by some dermatologists since the discovery of griseofulvin, still has a significant place in treatment.     

Isolation and characterization of Pediococcus halophilus from salted anchovies (Engraulis anchoita).

The presence of bacteria in salted anchovies during and at the end of the curing process was investigated. Attempts to isolate bacteria under aerobic or anaerobic conditions led to the isolation of only bacteria of the genus Pediococcus which were identified as Pediococcus halophilus. The isolates correspond to a rather heterogeneous group in which some of the members differ in some biochemical tests from the types described in the literature.     

Nucleotide sequence of dihydrofolate reductase genes from trimethoprim-resistant mutants of Escherichia coli. Evidence that dihydrofolate reductase interacts with another essential gene product

Summary We report the construction of recombinant plasmids containing the dihydrofolate reductase structural gene (fol) from several trimethoprim-resistant mutants of Escherichia coli. Strains carrying some of these plasmids produced approximately 6% of their soluble cell protein as dihydrofolate reductase and are therefore excellent sources of the purified enzyme for inhibitor binding or mechanistic studies. The nucleotide sequence of the fol region from each of the plasmids was determined. A plasmid derived from a K_i mutant which produced a dihydrofolate reductase with lowered affinity for trimethoprim contained a mutation in the structural gene that altered the sequence of the polypeptide in a conserved region which is adjacent to the dihydrofolate binding site. Two other independently-isolated mutants which overproduced dihydrofolate reductase had a mutation in the-35 region of the fol promoter. One of them, strain RS35, was also temperature-sensitve for growth in minimal medium. This phenotype was shown to be the result of an additional mutation in a locus unlinked to fol by P1 transduction. The fol regions from two temperature-independent revertants of strain RS35 were sequenced. One of these had a mutation within the dihydrofolate reductase structural gene which altered some properties of the enzyme. This confirmed some previous enzymological data which suggested that some revertants of strain RS35 had mutations in fol (Sheldon 1977). These results suggest that dihydrofolate reductase interacts physically with some other essential gene product in E. coli.     

Extracellular matrix components in uterine leiomyoma and their alteration during the tumour growth

It was found that both normal human myometrium and uterine leiomyoma contain several glycosaminoglycans. In contrast to many normal and tumour tissues the amount of hyaluronic acid is very low and the proportional amount of sulphated glycosaminoglycans is distinctly higher. It is of interest that heparan sulphate is the major glycosaminoglycan component both in normal myometrium, and in leiomyoma. The amount of hyaluronic acid in myometrium and in the leiomyoma is very low. No significant change in hyaluronate content was observed during the tumour growth. In contrast to that the amount of some sulphated glycosaminoglycans (heparan sulphate, keratan sulphate, chondroitin sulphates and heparin) distinctly increased. It is suggested that some of the GAGs participate in the creation of a storage depot for biologically active molecules (growth factors, enzymes) which are thereby stabilized and protected. Hydrolytic degradation of some GAGs may result in the release of some cytokines which may promote the tumour growth and stimulate collagen biosynthesis by tumour cells.     

Maynard Smith: amplifying the reasons for signal reliability

One of the many questions to which John Maynard Smith contributed was that of why most animal signals are reliable. He initially rejected the "handicap" argument but gradually accepted it, a process I briefly describe. This episode illustrated his preference for mathematical models over verbal ones, and the generosity with which he could change his mind. Even after accepting that some signals are reliable because of their strategic costs, he argued for a pluralistic approach to signal reliability. Signal complexity was a developing interest when he died. Signals usually involve several components, some of which appear to amplify other signal components. The terms "amplifier" and "index" require more thought to reduce the scope for semantic confusion. I conclude by describing Maynard Smith's fascination with peacocks Pavo cristatus.