Robust strictly positive real synthesis for *the fourth-order convex commnations

For the two fourth-order polynomials a ( s ) and b ( s ), the Hurrwitz stability of their convex combina tion is necessary and snfficient for the existence of a polynomial c (s) such that c ( s ) / a ( s ) and c ( s ) / b ( s ) are both strictly positive real.     

Expression of two insect-resistant genescryIA (b&c)/GNA in transgenic tobacco plants results in added protection against both cotton bollworm and aphids

The synthesizedBacillus thuringiensis insecticidal protein gene cryIA(b&c) and the synthesized geneGNA, (the mannose specific lectin from snowdrop (Galanthus nivalis)), tumefaciens have been inserted into plant expression vector pGW4BAI. Leave stripes ofNicotiana tabacum var. K326 have been transformed withAgrobacterium tumefaciens strain LBA4404 harboring the plant expression vector. 28 kanamycin resistant tobacco plants have been obtained. PCR and Southern blot analyses show that the foreigncryIA andGNA genes have been inserted into the genome of transformed tobacco plants. Haemagglutination assays show thatGNA has a functional activity. Leaf disc bioassays against cotton bollworm (H. armigera) show that the transgenic tobacco plants have a high insecticidal activity. The inhibition of aphid population in leaf disc bioassays againstMyzus persicae shows that the fecundity of aphid on transgenic plants is lower than that on untransformed plants; the aphid population on the transgenic tobacco plants is 25%–70% that on untransformed tobacco plants. ELISA analysis of ClyIA protein in tobcco leaves provides similar data to bioassay results. Through the two bioassays againstH. armigera andM. persicae, several transgenic tobacco plants showing high insect-resistant activities to both pests have been obtained.     

Interspecific hybridization ofHelicoverpa armigera andH. assulta (Lepidoptera: Noctuidae)

Reciprocal hybridization between Helicoverpa armigera (Hübner) and H. assulta Guenee followed by backcrossing of the hybrids (F₁) with H. armigera produced backcross (BC) lines consisting of fertile females and males. The F₁ of H. armigera female and H. assulta male had only male, no female sex. In this case Haldane’s rule applies, and therefore it is proved that the sex chromosomes of Helicoverpa species are of ZW type, and the female is the heterozygous sex. This hybrid also showed significant heterosis with the heaviest pupal weight, and when it was backcrossed with H. armigera female, the sex ratio of the BC offspring was distorted as 1∶4. The potential utilization of this hybrid in genetic controlling H. armigera was finally discussed.     

Expression ofBcl-2 in cells with different telomerase activities

Both telomerase andBcl-2 are important genes in controlling apoptosis. The activation of telomerase and the abnormal regulation ofBcl-2 are also closely related to carcinogenesis. However, little is known about the linkage between telomerase andBcl-2. The effect of activated telomerase on the expression ofBcl-2 has been investigated. It is demonstrated that in tumor and transformed cells with higher telomerase activity,Bcl-2 expression is significantly lower than that in telomerase negative or less telomerose activity cells. Further study showed that in the telomerase gene-transformed 2BS-fibroblasts,Bcl-2 expression is inhibited significantly while the exogenous telomerase catalytic subunit gene is re-expressed in fibroblasts. Results indicated that there might be a certain linkage between the expression of telomerase andBcl-2, and overexpression of exogenous telomerase gene might down regulate the expression ofBcl-2. They contributed equally to this work.     

Effects ofPKCα antisense RNA on human breast cancer cell proliferation and expression ofcyclinD1 andCDK4

The role of PKCα in human breast cancer cell proliferation and expression ofcyclinD1 andCDK4 has been investigated using inhibition ofPKCα expression by its antisense RNA. WhenPKCα expression was inhibited the rate of cell proliferation decreased apparently and the levels ofcyclinD1 andCDK4 mRNA were lower than the control. The results showed thatPKCα, a key member of signal transduction system, played an important role in human breast cancer cell proliferation and had a close relationship with expression ofcyclinD1 andCDK4 which control start of cell cycle.     

Morita equivalent blocks in subgroups of finite groups

0 IntroductionLeRte(f K.[,1]O), ,ki) .e b.e, aOips- am ocdoumlaplre tseys dtiesmcre(tese eva lCuhatpito .nII Iri nignwith unique maxi mal idealJ(O) suchthatJ(O) =(π)forπ∈O,Kis the quotient field ofOcharacteristic 0 ,andkis theresidue fieldO/(π)of characteristicp, wherepis a fixedpri me number .Inthis paper , we fix a finite groupG,andletKcontains all the |G|-throots of unity,where |G|is the or-der of finite groupG.In particular bothKandkare splittingfields of every subgroup ofG.D…     

Effect of mutation in ribosomal protein on translation elongation

Translation accuracy, translation elongation rate and translation processivity are three important parameters for each elongation cycle. To study the role of ribosomal protein in translation elongation, these parameters were measured simultaneously for the first time in threeEscherichia coli T83 mutantsrpsL, rplX andrpmA. The results suggested that the mutants of ribosomal protein S12(rpsL) and ribosomal protein L24(rplX) decreased the processivity of ribosome while the mutant of ribosomal protein L27(rpmA) had little effect on the processivity;rplX mutant andrpmA mutant had higher accuracy; the elongation rate ofrplX mutant was faster than that of the wild type, whereas the elongation rate ofrpmA mutant was the same as that of the wild type.     

The Effect of cdk-5 Overexpression and Overactivation on Tau Hyperphosphorylation in Cultured N2a Cells

Neurofibrillary tangles (NFTs) are one of the neuropathological hallmarks of Alzheimer‘s disease (AD) and abnormally hyperphosphorylated tau is the major protein of NFTs. It was reported that cyclin-dependent kinase5 (Cdk-5) could phosphorylate tau at most AD-related epitopes in vivo. In this study, we investigated the effect of cdk-5 overexpression on tau hyperphosphorylation in neuroblastoma N2a cells. We demonstrated that overexpression of cdk-5 whieh rcsul-ted in a 3.5-fold Cdk-5 activation in the transfected cells induced a dramatic increase in phosphorylation of tau at several phosphorylation sites. Overexpression of cdk-5 led to a reduced staining with antibody Tau-1 and an enhanced staining with antibody PHF-1, suggesting hyperphosphorylation of tau at Ser199/202 and Ser396/404 sites. It implies that in vitro overexpression of cdk-5 leads to Cdk-5 overactivation and tau hyperphosphorylation may be the underline mechanism.     

P15——a new tumor suppressor gene

In addition to the tumor suppressor genes such as Rb and p53, it has been found that some molecules of the same class named CKI (cyclin-dependent kinase inhibitor) also play an important role in the inhibition of tumorigenesis and the tumor progression. In the KIP and INK4 families of CKIs, p15 shares extensive homology with p16. Findings in many tumors and their cell lines show that the inactivation of p15 (deletion, mutation, rearrangement, etc.) is very frequent, and inactive p15 is involved in the progress of some tumors. These studies provide evidence that the p15 is a new tumor suppressor gene. Furthermore, the research on the molecular mechanism of p15 in regulation of cell proliferation shows that p15 can inhibit the growth of some kinds of tumor cells, and p15 is the mediator of TGF-β-induced cell arrest. Investigations on p15 in cell differentiation suggest that increased p15 is related to the change of malignant phenotype. These results supply clues for further interpretation about the molecular mechnism of cell cycle control and cell tumorigenesis. And they may provide theoretical and experimental basis for application of p15 to clinical therapy of tumors.     

Effect ofP15 INK4b/MTS2 on the proliferation of human hepatoma cells SMMC-7721

The full length cDNA coding forP15 ^INK4b, which is a cyclin-dependent kinase inhibitor, was cloned to plasmid PXJ41-neo (Eco R I /Xho I site) and the new constructed plasmid pXJp15 was obtained. pXJp15 was transferred into the human hepatoma SMMC-7721 cetls by lipofectine reagent. After G418 setection, a series of cetl lines stably expressing high levets ofP15 (named SHT) and the clone containing vector PXJ41-neo only (named SVXJ) were obtained by Northern and Western analysis. The results showed that the proliferation of SHT cells is inhibited compared with that of SVXJ cetls. Cell cycle analysis indicated that overexpressing ofP15 inhibited the growth of SHT cetls by decreasing progrssion of cetls from G1 to S and G2 to M phases. The levets ofc-Myc andc-Fos were obviously decreased in SHT cells compared with control cetls by Western blotting. The decreased expression of oncogene may be one of the molecular mechanisms of the effect ofP15 on the proliferation of in SHT cetls.     

A matrix version of the Wielandt inequality and its application to statistics

Suppose that A is an n × n positive definite Hemitain matrix. Let X and Y be n × p and n × q matrices (p+ q≤n), such that X* Y = 0. The following inequality is proved X*AY( Y* AY)-Y Y*AX≤( (λ1-λn)/(λ1+λn))2 X*AX, where λ1 and λn are respectively the largest and smallest eigenvalues of A, and M- stands for a generalized inverse of M. This inequality is an extension of the well-known Wielandt inequality in which both X and Y are vectors. The inequality is utilized to obtain some interesting inequalities about covari-ance matrix and various correlation coefficients including the canonical correlation, multiple and simple correlation.     

Generation of a recombinant herpes simplex virus which can provide packaging function for recombinant adeno-associated virus

The generation of a recombinant HSV (rHSV) that can provide packaging function for rAAV production is described. A set of cosmids including cos48, cos28, cos6, cosl4 and cos56, which represents the HSV-1 genome was used for generation of this rHSV.Rep andcap genes of AAV-2 were inserted intoXba I site ofUL2 gene on cod, generating cos6rcΔUL2. After being digested withPac I, cos6-rcΔUL2 and the other 4 cosmids were cotransfected into BHK-21 cells. The recombinant virus HSV1-rc/ΔUL2 carryingrep andcap genes was generated due to the homologous recombination of the 5 cosmids. The results showed that the existence ofrep andcap genes on this rHSV was stable from passage to passage and the rHSV could support the packaging of rAAV either in cells transiently transfected with AAV vector or in stable cell line harboring AAV vector. Further modification of this rHSV and optimization of conditions involved in rAAV preparation may lead to a large-scale production of rAAV in the near future.     

Preparation of (R)- and (S)-2-Allyl-1, 3, 2-dinaphtho (α, β) [d.f] dioxaborepin and their reactions with aldehydes

(R)- and(S)-2-Allyl-1,3,2-dinaphtho (α,β) [d.f] dioxaborepin ((R)-2 and(S)-2) have been first prepared by the reaction of(R)-(+)- or(S)-(−)-1, 1′-bi-2-naphthol and triallylborane in THF at room temperature, respectively.(S)-2 and(R)-2 are sensitive to moisture and oxygen in air and disproportionate easily to triallylborane and 1,1′-bi-2 naphthyl bis (1,1′-bi-2-naphtholborate) at ambient temperature. However, THF is a stabilizer for them. The reactions of(R)-2 or(S)-2 and some aliphetic or aromatic aldehydes in CH₂Cl₂ at −78°C for several hours afforded β-alkylenyl alcohols in up to 84.8%ee. Among them, optically active 1-(3, 5-dichlorophenyl)-3-butenol and 1-(2-methoxyphenyl)-3-butenol were first prepared Foundation item: Supported by the National Natural Science Foundation of China (29972033) Biography: Liu Dejun (1973), male, Ph. D, research direction: asymmetric synthesis     

Responses of woody plant root and xylem sap ATP to soil drying

The ATP in roots and xylem sap of two woody plant species, Platycladus orientalis and Acacia auriculiformis, subjected to rapid and slow soil drying has been determined employing firefly luciferase ATP assay method (sensitivity is at 10-12 mol ATP L-1). The ATP levels in the two species were 1.6 nmol·gDW-1 and 0.6 nmol·gDW-1 in roots, and 5.6 μmol·m-3 and 8 μmol ·m-3 in xylem sap, respectively. When plants of P. orientalis and A. auriculiformis were subjected to rapid soil drying, respectively, as soil water content (SWC) decreased from the normal level ( 0. 25 g ·gDW-1) to 0. 02 and 0. 06 g ·gDW-1, separately, plant water potential ( ) dropped to -4 and -3.2 MPa, differently, the ATP in roots decreased 99.7% and 42%, respectively . When the rapidly dried soil was watered for up to 6 d, SWC and were found to recover to their normal levels, but ATP content in roots of P. orientalis and A. auriculiformis recovered by 10% and 23%, respectively. When plants of P. orientalis and A. auriculiformis were subjected to slow soil drying, respectively, as SWC was found to decrease from the normal level to 0.1 and 0.13 g·gDW-1, separately, dropped to - 2.5 and - 2 MPa, differently, the ATP content in roots decreased 98% and 38%, respectively. When the slowly dried soil was watered for up to 8 d, ATP levels in roots of P. orientalis and A, auriculiformis recovered by 30% and 24%, respectively. However, ATP concentrations in xylem sap were not directly influenced by either SWC or . The plot dots of xylem sap ATP concentration versus root ATP content were found to be distributed diagonally. It is concluded that ATP in roots is more sensitive in response to SWC changes than that to and root-sourced ATP is a source of that in xylem sap. When plants are subjected to slow soil drying, the ATP levels in both root and xylem sap are higher than that to rapid soil drying.     

Root and xylem ABA changes in response to soil drying in two woody plants

Two woody plants, Platycladus orientalise (tolerant to drought) and Acacia auriculi-formis (sensitive to drought), have been subjected to rapid and slow soil drying. ABA levels in their roots and xylem sap have been determined using radioimmunoassay (RIA, sensitivity is 0.4 pmol per assay vial) with a monoclonal antibody against ( + )-ABA. ABA contents of P. orientalise and A. auriculiformis growing in well watered soil are 0.3 and 2.5 nmol·gDW-1 in roots and 1.6 and 0.4 μmol in xylem saps, respectively. A rapid soil drying has been applied to these two plants with soil water content (SWC) being reduced to 0.02 and 0.06 g·gDW-1 respectively. Under such treatment, ABA was increased by 22 times and 2 times in roots and by 7 times and 34 times in xylem saps respectively for P. orientalise and A. auriculiformis. After rewatering for 6 d, ABA in roots and xylem sap of both species returned to control levels. When a slow soil drying was applied, SWC was reduced to 0.1 and 0.13 g·gDW-1 respectively for P. orientalise and A. auriculiformis. ABA was increased by 5 times and 1.6 times in roots and by 6 times and 19 times in xylem saps respectively for these two plants. ABA in roots and xylem saps decreased to near control levels 8 d after watering. Plant leaf water potentials of both plants hardly changed at times when root and xylem ABA showed substantial increase in response to soil drying. It is concluded that ABA levels in the roots and xylem saps of P. orientalise and A. auriculiformis are more sensitively regulated than leaf water potential in response to soil drying and can act as a chemical signal in root-shoot communications of the drought stress.     

Construction of the glucose isomerase deficient strain ofStreptomyces M1033 by homologous recombination

After the establishment of the transformation conditions ofStreptomyces diastaticus No.7 Strain M1033, the integration plasmid pXW for homologous recombination, which contains a 600 bp fragment of incompleteGI (G138P. G247D) gene, has been constructed in order to realize the stable overexpression of theGI (G138P. G247D) which is valuable for large-scale industrial production. The Gigene’s disruption has been realized by pXW’s integration into M1033 chromosomes via homologous recombination andGI deficient strain ofStreptomyces M1033 has been obtained. The reliability of introduction of mutation has been proved by analysis of recombinant fragment and affirmance of existence of the mutation, as well as detection of the stability of the deficient strain.     

A novel tobacco gene coding for a product similar to bacterial two-component regulators

The two-component signaling system has been studied in bacteria. It takes part in signal transduction of adaptive behavior. Recent studies have shown that a similar two-component system is also present in eukaryotes. Examples of this areETRl andCKLl genes which may involve the signal transduction of plant hormone ethylene and cytokinin respectively. The cloning and characterization of a novel gene (NTHKl) fragment from tobacco are presented. Its partial sequence codes for a product which shows similarity to many two-component signaling proteins. Southern blot analysis indicated that there are 2 to 3 copies ofNTHKl gene in tobacco genome (allotetraploid). Homologous genes may also exist in other plants such as Arabidopsis, soybean and spinach. The expression ofNTHKl gene has also been analyzed in tobacco. Further studies on the isolation of full-length cDNA ofNTHKl gene will elucidate more clearly its function in signal perception and transduction.