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81.
Acetobacter acetii DSMZ3508 and related bacteria converted 2,2-dimethyl-1,3-propanediol into 3-hydroxypivalic acid (2,2-dimethyl-3-hydroxypropionic acid; 3HP) during submerged cultivation in mineral salt medium. The maximum yield of 3-hydroxypivalic acid was 24.4% of the fed substrate after 18 days. Cultivation parameters, as pH, cell density, optimal substrate concentration, and oxygen supply for the bioconversion process were determined. 相似文献
82.
Monte Carlo simulations of flexible two-dimensional model membranes embedded in three space dimensions are reported. We explain in detail the techniques how to simulate fluid open membranes and fluid closed membranes (vesicles). It is shown that polymerized open membranes are rough and flat. Accordingly, the two larger components of the inertia tensor are proportional to the number of monomers of the surface, λ3 ≈ λ2 ~ N, whereas the smallest λ1 ~ N 0.65. Polymerized vesicles are isotropic and their mean square radius of gyration is R 2 ~ λ k ~ N. In contrast, fluid membranes and vesicles exhibit crumpled shapes with λ k ~ N 0.8 for k = 1,2,3. A monomer on a fluid surface exhibits a time-dependent mean squared displacement of r 2 (t) ~ t 0.8. 相似文献
83.
84.
The in-situ recovery of ethanol from fermentation by different hydrophobic adsorbents has been studied. Liquid phase experiments have demonstrated that pentasil zeolites have a high selectivity for ethanol in the low concentration range. It is shown that the contact of the fermentation broth with the zeolite NaZSM-5 avoids the product inhibition. On the other hand, the ethanol production rate dramatically changes in dependence on the glucose-to-adsorbent ratio. 相似文献
85.
86.
Continental‐scale macrofungal assemblage patterns correlate with climate,soil carbon and nitrogen deposition 下载免费PDF全文
87.
Cornelia Speth Jörg T. Epplen Ilse Oberbäumer 《In vitro cellular & developmental biology. Animal》1991,27(8):646-650
Summary Oligonucleotide fingerprinting was applied to investigate the relatedness of several cell lines that were established between
1973 and 1977 from a teratocarcinoma. We were able to distinguish cell lines derived at different times. In addition, sublines
from one cell line (PYS-2) could be discriminated by using a combination of different probes. Therefore multilocus fingerprinting
with oligonucleotides is a useful method for monitoring changes in cell lines kept in culture for many generations.
This work was supported by the Deutsche Forschungsgemeinschaft (OB 66/2-1) and by the VW-Stiftung. 相似文献
88.
89.
During its life cycle, the amoebozoon Physarum polycephalum forms multinucleate plasmodial cells that can grow to macroscopic size while maintaining a naturally synchronous population of nuclei. Sporulation‐competent plasmodia were stimulated through photoactivation of the phytochrome photoreceptor and the expression of sporulation marker genes was analyzed quantitatively by repeatedly taking samples of the same plasmodial cell at successive time points after the stimulus pulse. Principal component analysis of the gene expression data revealed that plasmodial cells take different trajectories leading to cell fate decision and differentiation and suggested that averaging over individual cells is inappropriate. Queries for genes with pairwise correlated expression kinetics revealed qualitatively different patterns of co‐regulation, indicating that alternative programs of differential regulation are operational in individual plasmodial cells. At the single cell level, the response to stimulation of a non‐sporulating mutant was qualitatively different as compared to the wild type with respect to the differentially regulated genes and their patterns of co‐regulation. The observation of individual differences during commitment and differentiation supports the concept of a Waddington‐type quasipotential landscape for the regulatory control of cell differentiation. Comparison of wild type and sporulation mutant data further supports the idea that mutations may impact the topology of this landscape. 相似文献
90.
X Y Wu Y-Y Linko J Seppälä M Leisola P Linko 《Journal of industrial microbiology & biotechnology》1998,20(6):328-332
The enzymatic synthesis of aromatic polyesters by direct polyesterification between a diacid and a diol is described. The
effects of the type of substrate, type and quantities of lipase, temperature, vacuum, and reaction time on the synthesis of
aromatic polyesters were studied in detail. Among three lipases investigated, only Novozym 435 worked well for aromatic polyester
synthesis. Temperature and vacuum played an important role in obtaining a high molar mass of the aromatic polyesters. Furthermore,
with isophthalic acid and 1,6-hexanediol as substrates, the mass average molar mass of the polyester obtained increased with
an increase in the lipase quantity up to 0.375 g (11.7%, w/w of total reactor contents). The mass average molar mass of the
polyester was as high as 50000 g mol−1 in 168 h, with a polydispersity of PD ≈ 1.4.
Received 27 January 1998/ Accepted in revised form 19 May 1998 相似文献