Intensely potent anthracycline antibiotic oxaunomycin produced by a blocked mutant of the daunorubicin-producing microorganism

A new potent anthracycline antibiotic oxaunomycin was isolated from the culture broth of a blocked mutant derived from a baumycin producer and was identified as 7-O-(alpha-L-daunosaminyl)-beta-rhodomycinone. It exhibited about 100 times more strongly cytotoxic activity against leukemic L1210 cell culture than doxorubicin.     

Microbial conversion of anthracyclinones to carminomycins by a blocked mutant of Actinomadura roseoviolacea

New anthracycline antibiotics, 1-hydroxy-11-deoxycarminomycin II and 11-deoxycarminomycin II were produced by a blocked mutant MuW1 of Actinomadura roseoviolacea from epsilon-pyrromycinone and aklavinone, respectively. We found that the enzyme catalyzing hydroxylation at the C-11 position was not lost but was down regulated in the strain MuW1.     

Stimulation of cephalosporin production by methionine peptides in a mutant blocked in reverse transsulfuration.

The previously reported inability of methionine to stimulate cephalosporin C production in a cysteine auxotroph is due to cysteine interference with methionine uptake. In such a cse, "illicit transport" of alanylmethionine can be used to demonstrate the efficacy of methionine in such mutants blocked in the path from methionine to cysteine. This result supports the hypothesis that the stimulatory activity of methionine is not due to its ability to donate sulfur to the caphalosporin C molecule.     

Anthracycline metabolites from Streptomyces violaceus A262. II. New anthracycline epelmycins produced by a blocked mutant strain SU2-730

New anthracycline antibiotics, identified as epsilon-rhodomycinone glycosides, were isolated from the culture broth of a blocked mutant of beta-rhodomycin-producing Streptomyces violaceus A262. They were designated as epelmycins A, B, C, D and E, and assayed for their in vitro cytotoxicities against murine leukemic L1210 cell culture and the antimicrobial activities in comparison with known anthracycline antibiotics.     

一株海洋真菌产青霉酸的发酵优化研究

目的 对一株海洋真菌Penicillium janthinellum HK1-6的青霉酸代谢产物进行发酵优化,以期获得足量的化合物研究青霉酸对水稻纹枯病菌的拮抗性。方法 采用正交实验设计对真菌HK1-6产青霉酸的土豆液体培养基进行优化,采用高效液相色谱法对青霉酸产量进行定量分析。结果 研究表明,真菌HK1-6高产青霉酸的土豆液体培养基各因素最优水平为葡萄糖30 g,土豆200 g,海盐10 g,pH为4,产量可达0.908 g/L,而原发酵条件下青霉酸产量约为0.423 g/L。结论 真菌HK1-6采用最优土豆液体培养基发酵后,青霉酸的产量显著提高,产量较原培养条件提高约2.1倍。     

5-hydroxyramulosin,a new natural product produced by Phoma tropica,a marine-derived fungus isolated from the alga Fucus spiralis

The fungus Phoma tropica was isolated from the inner tissue of the marine brown alga Fucus spiralis. After large-scale cultivation the fungus was investigated for its secondary metabolite content and found to contain the new natural product 5-hydroxyramulosin ( 1) together with 7-methoxycoumarin. Both structures were elucidated using spectroscopic methods, mainly 1D and 2D NMR, and in the case of 1, a single crystal X-ray diffraction analysis.     

培养基优化设计提升多拉菌素生物发酵水平

运用响应面法优化了多拉菌素生产菌的发酵培养基。首先通过单因素实验发现正效应因子;接着采用Plackett-Burman(P-B)设计确定了黄豆饼粉、麦芽糊精和MgSO4是影响多拉菌素产量的显著因素;然后利用最陡爬坡试验分别找到3个因素的合理浓度范围;并进一步利用中心组合设计优化了黄豆饼粉、麦芽糊精和MgSO4的最佳浓度配比。筛选并优化得到了最适的培养基浓度为黄豆饼粉17.30g/L,麦芽糊精77.30g/L,MgSO4 1.50g/L,基于此,效价达到了589.43mg/L,验证实验结果与模型预测基本吻合,优化后的培养基工艺能够提升多拉菌素发酵单位20.37%。5L反应罐上发酵过程生理代谢参数变化表明：优化的培养基能够加促菌体的比生长速率,维持较高的氧消耗速率和产物合成速率,大幅度提升了多拉菌素的发酵生产效率。     

培养基优化设计提升多拉菌素生物发酵水平

运用响应面法优化了多拉菌素生产菌的发酵培养基。首先通过单因素实验发现正效应因子;接着采用Plackett-Burman(P-B)设计确定了黄豆饼粉、麦芽糊精和MgSO4是影响多拉菌素产量的显著因素;然后利用最陡爬坡试验分别找到3个因素的合理浓度范围;并进一步利用中心组合设计优化了黄豆饼粉、麦芽糊精和MgSO4的最佳浓度配比。筛选并优化得到了最适的培养基浓度为黄豆饼粉17.30g/L,麦芽糊精77.30g/L,MgSO4     

Regular and lasting neocortical spiking produced by systemic administration of a steroid derivative in the rat

The hypothesis was tested that sedation and stereotyped behaviour, developing in rats after the administration of the steroid derivative with γ-aminobutyric acid (GABA) antagonistic properties. R 5135, are of an epileptiform nature. Electroencephalographic (EEG) and visual evoked potentials (VEP) were recorded and behaviour was observed over not less than 5–7 hr after subconvulsive doses of R 5135. Doses of 2–4 mg/kg of the compound produced quasi-rhythmic spikes resembling experimental focal epileptic discharges in all rats. This epileptiform activity was accompanied by behavioural sedation and somnolence, followed by a build-up of stereotyped behaviour and sporadic episodes of epileptiform motor activity, developing 1–2 hr after injection. The secondary components (SNW) of the visual evoked potentials were suppressed by R 5135 and the primary potential (N₁) facilitated, virtually reducing the visual evoked potential to the form of an evoked spike.Pretreatment with the anticonvulsant GABAergic drugs γ-acetylenic GABA (GAG) (100 mg/kg). sodium valproate (VPA) (400 mg/kg) and diazepam (5 mg/kg) suppressed the motor components of seizure activity, producing severe ataxia, but not the electrographic manifestation of seizure activity. Neither γ-acetylenic GABA nor valproate significantly altered the latency to onset of spiking, although all three drugs did significantly reduce the frequency of discharges. Diazepam was the only anticonvulsant tested which completely suppressed spike activity in 3 of 5 rats. Moreover, R 5135 was found to antagonize diazepam. but not valproate induced suppression of secondary components of the visual evoked potential, suggesting that diazepam and R 5135 may compete for the same receptor.     

S-15183a and b, new sphingosine kinase inhibitors, produced by a fungus

In the course of our screening for inhibitors of sphingosine kinase, we found two active compounds in a culture broth of a fungus, Zopfiella inermis SANK 15183. The structures of the compounds, named S-15183a and b, were elucidated by a combination of spectroscopic analyses to be new azaphilone-type metabolites. S-15183a and b inhibited sphingosine kinase from rat liver with IC50 values of 2.5 and 1.6 microM, respectively. S-15183a also inhibited endogenous SPH kinase activity in intact platelets.     

Mutagenesis of OA-6129 carbapenem-producing blocked mutants and the biosynthesis of carbapenems

Streptomyces fulvoviridis A933 17M9 1501 is an A933 acylase-defective mutant derived from S. fulvoviridis A933 17M9 and thus produces the OA-6129 group of carbapenems and carbapenams. By further mutation of mutant 1501, 4 types of mutants (OA-6129 A + B1 + B2 producers; OA-6129 A + B2 producers; an OA-6129 A producer; non-producers) were obtained. The second type of mutant strains 4N 3607, 5NA 3949-40 and 5NE 252 proved useful for the fermentative production of carbapenem OA-6129 B2. These results of mutagenesis demonstrated that the sequence of carbapenem bioconversion in the horizontal route was hydroxylation at C-8----isomerization at C-6----sulfation at C-8 hydroxyl.