The extracellular processing and catabolism of hyaluronan in cultured adult articular cartilage explants.

Hyaluronan was shown to have the same turnover time as aggrecan in explant cultures of adult bovine articular cartilage. Inclusion of fetal calf serum in the culture medium resulted in a similar decrease in the rate of catabolism of both hyaluronan and proteoglycan. Less than 9% of the hyaluronan lost from the explants in the course of the experiment was recovered from the culture medium as hyaluronan, suggesting that the catabolism of hyaluronan involves the uptake of this glycosaminoglycan by the chondrocytes. Analysis of the molecular size of the newly synthesized hyaluronan in these cultures showed that the hyaluronan was initially synthesized as large macromolecules that were gradually depolymerized with time within the extracellular matrix. The resulting size distribution of newly synthesized hyaluronan molecules after 12 days in culture was similar to that determined for the endogenous hyaluronan. The kinetics of depolymerization of the newly synthesized hyaluronan was consistent with a random fragmentation of the macromolecule. The rate constants for the depolymerization of hyaluronan indicate that oxygen-derived radicals may be involved in the fragmentation of this macromolecule. Inclusion of either cycloheximide or proteinase inhibitors in the medium of the explant cultures resulted in a marked decrease in the rate of loss of hyaluronan from the tissue and in the inhibition of the depolymerization of the newly synthesized macromolecule. This suggests that both the catabolism and the depolymerization of hyaluronan are cell mediated and depend on metabolically active cells.     

Hwabyung: The construction of a korean popular illness among korean elderly immigrant women in the United States

The cultural construction of Hwabyung, a Korean culture-bound syndrome, is explored among a sample of 20 elderly Korean immigrant women in the United States. Hwabyung results when distressed emotions associated with the specifically Korean way of perceiving and reacting to intolerable and tragic life situations cause bodily symptoms by interfering with the harmony of Ki (vital energy). Korean elderly immigrants report a broad range of symptoms associated with Hwabyung; they less frequently report the epigastric mass, which had been considered the cardinal symptom by cosmopolitan and traditional medical writers. Hwabyung is treated holistically with psychosocial support from family, spiritual comfort, home and popular remedies, traditional Korean medicine, and biomedical treatments. Hwabyung provides a way of conceptualizing and resolving emotional distress through somatization among Korean elderly immigrant women.     

版纳鱼螈和双带鱼螈核型的比较研究

本文对版纳鱼螈的核型作了观察,并与双带鱼螈进行了比较。两者的核型基本一致,均为2n=42,但版纳鱼螈的NF=62,而双带鱼螈的NF=60;版纳鱼螈的染色体有中部着丝粒、亚中部着丝粒和端部着丝粒三种类型,而双带鱼螈则无亚中部着丝粒的染色体。     

Genetic mapping studies of 40 loci and 23 cosmids in chromosome 11p13-11g13, and exclusion of μ-calpain as the multiple endocrine neoplasia type 1 gene

Forty loci (16 polymorphic and 24 non-polymorphic) together with 23 cosmids isolated from a chromosome 11-specific library were used to construct a detailed genetic map of 11p13-11g13. The map was constructed by using a panel of 13 somatic cell hybrids that sub-divided this region into 19 intervals, a meiotic mapping panel of 33 multiple endocrine neoplasia type 1 (MEN1) families (134 affected and 269 unaffected members) and a mitotic mapping panel that was used to identify loss of heterozygosity in 38 MENI-associated tumours. The results defined the most likely order of the 16 loci as being: 11pter-D11S871(D11S288, D11S149)-11cen-CNTF-PGA-ROM1-D11S480-PYGM-SEA-D11S913-D115970-D11S97-D11S146-INT2-D11S971-D11S533-11gter. The meiotic mapping studies indicated that the most likely location of the MEN1 gene was in the interval flanked by PYGM and D11S97, and the results of mitotic mapping suggested a possible location of the MEN1 gene telomeric to SEA. Mapping studies of the gene encoding μ-calpain (CAPN1) located CAPN1 to llg13 and in the vicinity of the MEN1 locus. However, mutational analysis studies did not detect any germ-line CAPN1 DNA sequence abnormalities in 47 unrelated MEN1 patients and the results therefore exclude CAPN1 as the MEN1 gene. The detailed genetic map that has been constructed of the 11p13-11g13 region should facilitate the construction of a physical map and the identification of candidate genes for disease loci mapped to this region.     

Tobacco (Nicotiana tobaccum) nuclear transgenics with high copy number can express NPTII driven by the chloroplast psbA promoter

A chloroplast expression vector containing the NPTII gene under the control of apsbA promoter (psbA-NPTII) was constructed, and was biolistically delivered into both suspension cells and leaf strips of tobacco (Nicotiana tabaccum). Analyses of subsequently recovered kanamycin-resistant transgenic plants indicate that the psbA-NPTII gene was not located in the chloroplast, but was in the nucleus in very high copy number. This conclusion was based upon results from: (1) Southern hybridization analyses of chloroplast and nuclear DNAs using NPTII, chloroplast-marker, and nuclear-marker probes; (2) pulse-field gel electrophoresis; and (3) kanamycin screening of sexual progenies. This study suggests that the nuclear expression of the NPTII gene may have been associated with many copies of the psbA-NPTII construction. Very high copy number in the nucleus might either allow NPTII expression from the otherwise inadequate psbA promoter, or might increase the chance of recombining with upstream tobacco regulatory sequences.     

Plant regeneration from somatic embryos ofTaxus brevifolia

Summary Taxusbrevifolia is the source of paclitaxel (Taxol®), an anticancer drug. A method for regeneration ofTaxus brevifolia from immature zygotic embryos via somatic embryogenesis is described. Embryogenic callus tissues were obtained by culturing immature zygotic embryos on Lloyd and McCown medium (MCM) supplemented with 160 M 2,4-dichlorophenoxyacetic acid (2,4-D) + 5 M benzylaminopurine (BA) + 5 M naphthaleneacetic acid (NAA) for 4 weeks. Putative embryoids were obtained following transfer of cultures to MCM medium supplemented with 4 M BA + 5 M kinetin + 1 M NAA for 6 to 8 weeks. Conversion of embryos was obtained on MCM medium supplemented with 40 M abscisic acid (ABA) + 1% activated charcoal. Development of bipolar structures with recognizable shoot and root apices was observed in somatic embryos. Five percent of somatic embryos were regenerated into plantlets on half-strength growth regulator-free MCM medium.     

Specificity of binding of beta-glucoside activators of ryegrass (1-->3)-beta-glucan synthase and the synthesis of some potential photoaffinity activators.

Structure-activity relationships among glycoside activators of ryegrass (Lolium multiflorum) (1-->3)-beta-glucan synthase were investigated using a number of natural and synthetic glycosides, including some carrying photoaffinity functions. There is an absolute requirement for a beta-D-glycosyl moiety in the activator, both S- and N-glucosides are active, and the position of the glucosidic linkage in beta-glucose disaccharides has a significant effect on the affinity of binding. However, the binding requirement does not extend beyond a single beta-D-glucosyl residue, and beta-D-oligoglucosides are less effective than disaccharides. The nature of the aglycon has a major influence on the binding affinity. Hydrophobic aglycons lower the concentration required for half-maximal stimulation of the enzyme obtained from an Eadie-Hofstee plot of kinetic data (Ka) for activation, but charge aglycons increase Ka. Relative to methyl-beta-D-glucoside and cellobiose (Ka 1.1 mM), the most potent compounds tested were N-[4-(benzoyl)benzoyl]-beta-D-glucosylamine and 2'-[4-azidosalicylamino]ethyl-1-thio-beta-D-glucoside with K(a)s of approximately 30 microM. The latter also was tested for its potential to specifically label the beta-glucoside-binding site on the synthase, but under the conditions used the binding was found to be nonspecific.     

The genetics of blackleg [Leptosphaeria maculans (Desm.) Ces. et De Not.] resistance in rapeseed (Brassica napus L.)

The genetic control of adult-plant blackleg [Leptosphaeria maculans (Desm.) Ces. et De Not.] resistance in rapeseed (Brassica napus L.) was studied in the F₂ and first-backcross populations of the cross Maluka (blackleg-resistant) x Niklas (highly susceptible). A L. maculans isolate possessing high levels of host specificity (MB2) was used in all inoculations. Resistance/susceptibility was evaluated using three separate measures of crown-canker size, i.e. the percentage of crown girdled (%G), external lesion length (E) and internal lesion area (%II). Disease severity scores for the F₂ and first-backcross populations based on E and %II gave discontinuous distributions, indicating major-gene control for these measures of resistance; but those for %G were continuous, indicating quantitative genetic control for this measure. Chi-square tests performed on the (poorly-defined) resistance classes, based on E, in the F₂ and first-backcross populations indicated the likelihood for resistance being governed by a single, incompletely dominant major gene. Although the distributions of the F₂ and first-backcross populations, based on%II, were clearly discontinuous, the observed segregation ratios for resistance and susceptibility did not fit any of the numerous Mendelian ratios which were considered. Differences in inheritance of resistance according to the assessment method and blackleg isolate used, were discussed.