Biomedical subjects

Yu Ziniu

Publications and source records attributed to Yu Ziniu.

6 recordsLinked to original sources

PubMed2005

Medium optimization by response surface methodology for poly-gamma-glutamic acid production using dairy manure as the basis of a solid substrate.

Dairy manure, supplemented with agro-industrial materials, was used as the solid substrate for high yield of poly-gamma-glutamic acid (gamma-PGA) by Bacillus subtilis CCTCC202048. The solid-state fermentation medium was optimized by response surface methodology. In the first optimization step, a Plackett-Burman design was used to evaluate the influence of related factors. Wheat bran, soybean cake and glutamic acid were found to be more compatible supplement with dairy manure and positively influenced on gamma-PGA production. In the second step, the concentrations of the three supplemental nutrients above were further optimized using a Box-Behnken design. The average gamma-PGA yield (4.70%) in triplicate under optimal conditions was obtained on the laboratory scale, whereas it was 3.58% at compost experiment. These would lay a foundation for lessening the pollution of dairy manure, increasing fertilizer efficiency and exploring a late-model organic fertilizer that retains water and nutrients.

Animals↗

PubMed2004

Microcalorimetric investigation on the growth model and the protein yield of Bacillus thuringiensis.

A novel microcalorimetric technique based on the bacterial heat output was applied to evaluate the special growth model, the protein expression and the generation time of Bacillus thuringiensis for the first time. The thermogenic curves of the aerobic metabolism of B. thuringiensis strains YBT-833, YBT-1520 and YBT-833-2-1 were determined by using an LKB-2277 BioActivity Monitor. The analysis of the thermogenic curves indicated both the mutant strain and the wild-type strains followed the same linear growth model during sporulation. The metabolism heat output revealed heat output was correlated to the yield of the insecticidal crystal proteins (ICPs) very well, the more protein product, and the less heat output. Based on the data acquired, we proposed that this method could be a useful tool in monitoring the fermentation of B. thuringiensis.

Bacillus thuringiensis↗

PubMed2003

Study of the thermokinetic properties of copper(II) on Escherichia coli growth.

By using an LKB2277 Bioactivity Monitor, stop-flow mode, the power-time curves of Escherichia coli at 37 degrees C affected by Cu(II) were determined. Some parameters, such as growth rate constants k, inhibitory ratio I, the heat output Qlog in the log phase, and the generation times G were obtained. According to these parameters, we found that a low concentration of Cu(II) (0-20 microg/mL) had an promoting action on the growth of E. coli, but a high concentration of Cu(II) (40-100 microg/mL) had an inhibitory action. The toxicity of Cu(II) can also be expressed as the half-inhibitory concentration IC50; the value is 69.7 microg/mL. The assay is quantitative, inexpensive, and versatile.

Algorithms↗

PubMed2003

Microcalorimetric investigation of the effect of manganese(II) on the growth of Tetrahymena shanghaiensis S199.

The heat output of and the effect of manganese (II) on Tetrahymena shanghaiensis S199 growth metabolism has been determined by means of a LKB-2277 BioActivity monitor. Different concentrations of manganese(II) ions have different effects on the growth of T. shanghaiensis. At low concentrations (0-40 microg/mL) culture growth is promoted, whereas high concentrations (60-800 microg/mL) slow growth. Furthermore, concentrations of 1200 microg/mL or greater stop the growth of this protozooa completely.

Algorithms↗

PubMed2003

Effect of Sm(3+) ion on growth of Bacillus thuringiensis by microcalorimetry.

By using an LKB-2277 Bioactivity Monitor, cycle-flow method, the thermogenic curves of aerobic growth for Bacillus thuringiensis cry II strain at 28 degrees C have been obtained. The metabolic thermogenic curves of B. thuringiensis cry II contained two distinct patterns: the first reflects the changes during the bacterial growth phase and the second corresponds to the sporulation phase. From these thermogenic curves in the absence and presence of Sm(3+) ions, the thermokinetic parameters such as the growth rate constants k, the interval time tau(I), the maximum power P (max 1) and heat-output Q(log) for log phase, the maximum power P (max 2) and heatoutput Q(stat) for stationary phase, the heat-output Q(spor) for sporulation phase and total heat effects QT are calculated. Sm(3+) ion has promoting action on the growth of B. thuringiensis cry II in its lower concentration range; on the other hand, this ion has inhibitory action on the sporulation of B. thuringiensis in its higher concentration range. We also found that the effects of Sm(3+) ion on B. thuringiensis during the sporulation phase were far greater than that during the bacterial phase. It is concluded that the application of B. thuringiensis for controlling insecticides is not affected by the presence of the rare-earth elements in the environmental ecosystem.

Bacillus thuringiensis↗

PubMedDate not supplied

The action of Cu2+ on Bacillus thuringiensis growth investigated by microcalorimetry.

By using an LKB-2277 Bioactivity Monitor, ampoule mode, the heat output of Bacillus thuringiensis growth metabolism has been determined at 28 degrees C and effect of Cu2+ on B. thuringiensis growth was studied. Copper has been regarded as an essential trace element for life. Its deficiency may be the cause of diseases. Cu2+ of different concentration have different effects on B. thuringiensis growth metabolism, Cu2+ of low concentration (0-30 micrograms/ml) can promote the growth of B. thuringiensis, and Cu2+ of high concentration (40-120 micrograms/ml) is able to inhibit its growth and B. thuringiensis can't grow at all when the concentration of Cu2+ is up to 130 micrograms/ml.

Bacillus thuringiensis↗