On the classification of Calligonum juochiangense and C. pumilum (Polygonaceae)

After observing specimens of Calligonum pumilum Losinsk. and C. juochiangense Y. X. Liou in both the field and in herbarium collections, it was found that the morphological characters of these two species are quite different, especially with respect of the twisted direction of fruit ribs, number of bristle rows along each rib, rigidity and degree of interweaving of bristles, as well as their geographic distribution. Therefore, it is concluded that C. pumilum and C. juochiangense should be accepted as two independent species.     

The response ofAzolla pinnata R. Brown to the split application of phosphorus and the transfer of assimilated phosphorus to flooded rice plants

A field experiment was conducted at the Bangladesh Rice Research Institute, Joydebpur, Dhaka during the late wet season. Basal application of P at both 5 and 10 kg ha⁻¹ significantly increased total biomass production and nitrogen fixation byAzolla pinnata R. Brown (local strain). Addition of both 5 and 10 kg P ha⁻¹ in equal splits at inoculation and at six day intervals thereafter during growth periods of 12, 24 and 36 days increased biomass production and nitrogen fixation by Azolla over that attained with the basal application. Biomass and nitrogen fixation using a split application of 5 kg P ha⁻¹ exceeded that attained with basal application of 10 kg P ha⁻¹ and split application of 10 kg P ha⁻¹ resulted in 0.58, 11.2, and 18.3 t ha⁻¹ more biomass, and 0.47, 18.9, and 18.3 more kg fixed N ha⁻¹ at 12, 24 and 36 days, respectively, than the same amount applied as a basal application. Analyses indicated that the critical level of dry weight P in Azolla for sustained growth was in the range of 0.15–0.17%. Compared with the control, where no P was added, and additional 30 and 36 kg N ha⁻¹ were fixed after 24 and 36 days, respectively, when P was provided at 10 kg ha⁻¹ using a split application. A separate field study showed that flooded rice plants received P from incorporated Azolla with about 28% of the P present in the supplied Azolla being incorporated into the rice plants.     

Cytotoxic T lymphocyte recognition of novel allodeterminants expressed on in vitro selected H-2Kb mutants

In the present study, in vitro derived H-2Kb mutants have been examined by alloreactive CTL. Two mutants, R8.24 and R8.246, have been shown to express novel determinants detected by CTL generated against some but not all in vivo derived Kb mutants. BDF1 anti-bm3, anti-bm11, anti-bm19, anti-bm23, and anti-bm6 CTL populations lyse the two R8 variants. The novel determinants expressed on the R8 mutants detected by the bm3 and bm23-specific CTL appear to differ from the determinant recognized by the bm6-specific CTL. No new serologically defined determinants were detected on any of 18 independent R8 variants. However, these results do not rule out the existence of new determinants which could be recognized by antibodies. Finally, the relationship between the T cell recognition of the in vivo and in vitro derived mutants and their use in understanding the structure/function relationships between the immune response and class I Ag based on recent crystallographic analyses is discussed.     

Directional Ca2+ effect on stimulation of secretion of common mucins and unique sulphate-rich components from chicken trachea in vitro

High submucosal Ca2+ (3.6-18 mM) significantly increased the secretion of a common high molecular weight fibrillar mucin (approx. Mr is greater than 2.10(6)) and also elicited the secretion of an additional low molecular weight component (approx. Mr 325,000). Low luminal Ca2+ (0.018 mM) also significantly increased the secretion of a common high molecular weight gelatinous mucin (approx. Mr is greater than 2.10(6)) and elicited the secretion of an additional low molecular weight component (approx. Mr 46,200). The additional low molecular weight components were more heavily sulphated (6.7 and 4.2%) than common high molecular weight mucins (2.1 and 1%). The low molecular weight components and high molecular weight mucins were secreted as aggregates which could be dissociated by EGTA. The low molecular weight components and high molecular weight mucins were different in the number of their glycoprotein constituents and in the ion-exchange chromatographic profiles and the carbohydrate and ester sulphate residue content of their acidic glycoproteins.     

Identification of monoclonal antibodies specific for the T cell receptor complex by Fc receptor-mediated CTL lysis

Monoclonal antibodies (mAb) directed at the T cell receptor complex (TcR) on cloned T cells have generally been identified by their ability to inhibit the clone's antigen-specific function. Because such inhibition is highly dependent on antibody concentration and affinity, detection of anti-clonotypic antibodies to murine alloreactive T cells has been very difficult. In this report, an alternative method is described on the basis of the ability of antibodies specific for the TcR complex to activate T cells in an antigen-independent manner. The assay is based upon the observation that soluble antibodies to human T3 promote lysis of irrelevant, Fc receptor-positive targets by a human CTL line. By using this approach, an anti-TcR mAb has been identified among a panel of murine mAb generated against an alloreactive CTL clone. Induction of lysis by soluble anti-TcR mAb has been shown to require both the expression of Fc receptors on the target cell and conjugate formation between the effector and the target cell. This assay provides a screening procedure that is much more sensitive than inhibition of function, and it preferentially detects antibodies specific for cell surface molecules involved in T cell activation.     

Condensed tannins: co-occurrence of procyanidins,prodelphinidins and profisetinidins in the heartwood of Acacia baileyana

The flavonoids and condensed tannins of the heartwood of Acacia baileyana var. purpurea are described. In conformity with other Acacia species, the hydroxylation pattern of the flavonoids is of the resorcinol type but, in sharp contrast, the tannins are heterogeneous consisting of a mixture of the resorcinol and phtoroglucinol series. Dimeric proanthocyanidins of the phloroglucinol type were absent and this exception to the general observation that they invariably co-occur with the polymers may be explained by the relative nucleophilicity of the aromatic A-rings.     

Analysis of cell-growth-phase-related variations in hyaluronate synthase activity of isolated plasma-membrane fractions of cultured human skin fibroblasts.

Hyaluronate synthase activity is localized exclusively in plasma-membrane fractions of cultured human skin fibroblasts. The enzyme activity of plasma membranes prepared from exponential-growth-phase cells was about 6.5 times that of stationary-growth-phase cells. Hyaluronate synthase from exponential-growth-phase cells exhibited lower Km and higher Vmax. values for both UDP-N-acetylglucosamine and UDP-glucuronic acid and higher rate of elongation of hyaluronate chains compared with the enzyme from stationary-growth-phase cells. Hyaluronate synthase exhibited an extremely short half-life, 2.2 h and 3.8 h respectively when cells were treated with cycloheximide and actinomycin D. The cell-growth-phase-dependent variations in hyaluronate synthase activity appear to be due to its high turnover rate as well as due to some post-translational modification of the enzyme protein as cells progress from early exponential to stationary growth phase. The isolated plasma membranes contained a protein (Mr approx. 450,000) that was selectively autophosphorylated from [gamma-32P]ATP in vitro in the presence of hyaluronate precursors in the reaction mixture and that also exhibited some hyaluronate-synthesis-related properties. The 32P-labelled protein isolated from plasma membranes of exponentially growing cells expressed an efficient UDP-[14C]glucuronic acid- and UDP-N-acetyl[3H]glucosamine-binding activity and was able to synthesize oligosaccharides (Mr 5000) of [14C]glucuronic acid and N-acetyl[3H]glucosamine residues. The corresponding protein of stationary-growth-phase cells, which expressed much higher nucleotide-sugar-precursor-binding activity, appeared to have lost its oligosaccharide-synthesizing activity.     

青海藏族青少年骨龄与生长发育关系研究

本文报告了青海省境内,世居在海拔3000-4000米地区的728名7-18岁健康藏族青少年学生的手、腕部骨骼发育情况,对骨化中心出现和骨骺愈合求出了50%出现年龄,并对骨龄与青春期身高突增的关系及与月经初衬潮的关系进行了分析。     

Identification of quantitative trait loci for plant height, lodging, and maturity in a soybean population segregating for growth habit

The use of molecular markers to identify quantitative trait loci (QTLs) has the potential to enhance the efficiency of trait selection in plant breeding. The purpose of the present study was to identify additional QTLs for plant height, lodging, and maturity in a soybean, Glycine max (L.) Merr., population segregating for growth habit. In this study, 153 restriction fragment length polymorphisms (RFLP) and one morphological marker (Dt1) were used to identify QTLs associated with plant height, lodging, and maturity in 111 F₂-derived lines from a cross of PI 97100 and Coker 237. The F₂-derived lines and two parents were grown at Athens, Ga., and Blackville, S.C., in 1994 and evaluated for phenotypic traits. The genetic linkage map of these 143 loci covered about 1600 cM and converged into 23 linkage groups. Eleven markers remained unlinked. Using interval-mapping analysis for linked markers and single-factor analysis of variance (ANOVA), loci were tested for association with phenotypic data taken at each location as well as mean values over the two locations. In the combined analysis over locations, the major locus associated with plant height was identified as Dt1 on linkage group (LG) L. The Dt1 locus was also associated with lodging. This locus explained 67.7% of the total variation for plant height, and 56.4% for lodging. In addition, two QTLs for plant height (K007 on LG H and A516b on LG N) and one QTL for lodging (cr517 on LG J) were identified. For maturity, two independent QTLs were identified in intervals between R051 and N100, and between B032 and CpTI, on LG K. These QTLs explained 31.2% and 26.2% of the total variation for maturity, respectively. The same QTLs were identified for all traits at each location. This consistency of QTLs may be related to a few QTLs with large effects conditioning plant height, lodging, and maturity in this population.     

Molecular markers associated with seed weight in two soybean populations

Seed weight (SW) is a component of soybean, Glycine max (L.) Merr., seed yield, as well as an important trait for food-type soybeans. Two soybean populations, 120 F₄-derived lines of YoungxPI416937 (Pop1) and 111 F₂-derived lines of PI97100xCoker 237 (Pop2), were mapped with RFLP makers to identify quantitative trait loci (QTLs) conditioning SW across environments and populations. The genetic map of Pop1 consisted of 155 loci covering 973 cM, whereas Pop2 involved 153 loci and covered 1600 cM of map distance. For Pop1, the phenotypic data were collected from Plains, GA., Windblow, N.C., and Plymouth, N.C., in 1994. For Pop2, data were collected from Athens, GA., in 1994 and 1995, and Blackville, S.C., in 1995. Based on single-factor analysis of variance (ANOVA), seven and nine independent loci were associated with SW in Pop1 and Pop2, respectively. Together the loci explained 73% of the variability in SW in Pop1 and 74% in Pop2. Transgressive segregation occurred among the progeny in both populations. The marker loci associated with SW were highly consistent across environments and years. Two QTLs on linkage group (LG) F and K were located at similar genomic regions in both populations. The high consistency of QTLs across environments indicates that effective marker-assisted selection is feasible for soybean SW.