Grape breeding in China

The paper introduces the achievements of grape breeding in China since 1950. So far, around 50 new varieties and many new lines of grape have been produced. Some new varieties are cold resistant, disease resistant with high yield and are suitable for making wine. Some are early maturing with large, seedless berries. Some are suitable for the climate of high humidity and for cultivation in rainy areas of southern China. Some bear large clusters and berries of beautiful appearance and are of high yield and quality. Some are suitable for canning and making juice

Studies on germplasm resources of wild grape species (Vitis spp.) in China

China is the country rich in germplasm resources of the genus Vitis, with nearly 40 native species. This paper introduces into their geographical distribution and chief characteristics, utilization and research on 11 wild species

Stability Analysis of a Population Model with Maturation Delay and Ricker Birth Function

A single species population model is investigated, where the discrete maturation delay and the Ricker birth function are incorporated. The threshold determining the global stability of the trivial equilibrium and the existence of the positive equilibrium is obtained. The necessary and sufficient conditions ensuring the local asymptotical stability of the positive equilibrium are given by applying the Pontryagin's method. The effect of all the parameter values on the local stability of the positive equilibrium is analyzed. The obtained results show the existence of stability switch and provide a method of computing maturation times at which the stability switch occurs. Numerical simulations illustrate that chaos may occur for the model, and the associated parameter bifurcation diagrams are given for certain values of the parameters

Effect of Electrical Current Stimulation on the Metabolic Flux Distribution of Corynebacterium crenatum under Anaerobic Conditions

The effect of electrical current stimulation on the fermentation characteristics of Corynebacterium crenatum under anaerobic conditions was investigated, and the impacting mechanism was discussed by calculating metabolic fluxes and measuring gene expression levels. It turned out that electrical current stimulation greatly contributed to glucose metabolism and succinic acid synthesis. Applying an electric current of −5 mA increased the glucose consumption rate, the concentration of succinic acid in the fermentation broth, the yield of succinic acid, the metabolic flux in the pentose phosphate pathway (HMP), and intracellular NADH/NAD+ ratio by 27.4%, 109.4%, 62.5%, 150.6% and 30.8% respectively, compared with the control group (0 mA). The results of metabolic flux and key enzyme gene expression levels indicated that glucose-6-phosphate was the key node that could influence the production of succinic acid. Electrical current stimulation up-regulated the expression levels of the glucose-6-phosphate dehydrogenase gene (zwf) and the phosphoenolpyruvate carboxylase gene (pepc), and increased the metabolic fluxes in the HMP and succinic acid biosynthesis pathway, thereby increasing the production of succinic acid. These results support the combined application of electrochemistry and fermentation

A Differential Equation Model of HIV Infection of CD

An epidemic model of HIV infection of CD4+ T-cells with cure rate and delay is studied. We include a baseline ODE version of the model, and a differential-delay model with a discrete time delay. The ODE model shows that the dynamics is completely determined by the basic reproduction number R01, a unique endemic equilibrium exists and is globally stable in the interior of the feasible region. In the DDE model, the delay stands for the incubation time. We prove the effect of that delay on the stability of the equilibria. We show that the introduction of a time delay in the virus-to-healthy cells transmission term can destabilize the system, and periodic solutions can arise through Hopf bifurcation

The Painlevé Tests, Bäcklund Transformation and Bilinear Form for the KdV Equation with a Self-Consistent Source

The Painlevé property and Bäcklund transformation for the KdV equation with a self-consistent source are presented. By testing the equation, it is shown that the equation has the Painlevé property. In order to further prove its integrality, we give its bilinear form and construct its bilinear Bäcklund transformation by the Hirota's bilinear operator. And then the soliton solution of the equation is obtained, based on the proposed bilinear form

Persistence of an SEIR Model with Immigration Dependent on the Prevalence of Infection

We incorporate the immigration of susceptible individuals into an SEIR epidemic model, assuming that the immigration rate decreases as the spread of infection increases. For this model, the basic reproduction number, R0, is found, which determines that the disease is either extinct or persistent ultimately. The obtained results show that the disease becomes extinct as R01

Analysis of beauvericin in Isaria cicadae Miquel culture on different media

Objective To analyze beauvericin and enniatins concentrations in the culture complex after Isaria cicadae Miquel was inoculated on different media for certain time. Methods One strain of Isaria cicadae Miquel was inoculated on 4 kinds of liquid culture media and 4 kinds of solid culture media. After incubation for 1-7 weeks under 25 ℃, high performance liquid chromatography tandem mass spectrometry was employed to detect beauvericin and enniatins. Results The detection rates of beauvericin in Isaria cicadae Miquel culture on 4 kinds of liquid media ranged between 42.9%-100.0%, and the beauvericin concentrations varied from 1.0 to 94.6 μg/L. The positive rates of beauvericin in Isaria cicadae Miquel culture on 4 kinds of solid media were 100.0%, and the beauvericin concentrations ranged from 60.9 to 44 677.5 μg/kg. Enniatins were negative for Isaria cicadae Miquel on 8 kinds of culture media. Conclusion The strain of Isaria cicadae Miquel used in our study could produce beauvericin in 8 kinds of culture media after incubation for certain time, and the beauvericin concentrations in solid media were much higher than in liquid media. The strain of Isaria cicadae Miquel didn’t produce enniatins in 8 kinds of culture media after incubation for certain time