吸水链霉菌、放线菌Sp.253和金色毛壳菌的次生代谢产物研究

链霉菌是十分重要的一类放线菌，绝大多数的抗生素都由该类细菌产生。毛壳属真菌是一类重要的丝状真菌，从中也发现有很多结构新颖、活性独特的活性物质。因此本论文对两株链霉菌的活性成分及一株金毛壳菌的次生代谢产物进行了研究。 1．从吸水链霉菌（Streptomyces hygroscopicus 1.358）液态发酵产物（乙酸乙酯提取物）中分离得到3个化合物，通过波谱方法鉴定为RK955A (1)、Nigericin（2）、Elaiophylin（3）。以青霉素耐药-金黄色葡萄球菌作为指示菌的抗菌活性测定表明，三者均具有较强抗菌活性。 2．通过抗肿瘤体外活性筛选模型筛选得到得到一株链霉属土壤放线菌，从中分离得到六个化合物：苯乙酰胺（4）、苯丙酰胺（5）、肉桂酰胺（6）、3-（N-（甲酰胺基）乙酰基）吲哚（7）、鸟苷磷酸（8）、鸟苷（9）。 3．从金色毛壳菌（Chaetomium aureus）的固态培养物中分离得到13个化合物，利用波谱方法将其鉴定为：金毛壳菌素A（10）、金毛壳菌素B（11）、Eugenetin（12）、Eugenitol（13）、Chaetoquadrin A（14）、Chaetoquadrin B（15）、Chaetoquadrin G（16）、Chaetoquadrin H（17）、Chaetochromin A（18）、Sterigmatocystin（19）、O-methylsterigmatocystin（20）、3β-羟基-麦角甾-5，7，22-三烯（21）和过氧麦角甾醇（22）。 4．综述了聚醚类抗生素的结构、生物合成、生物活性及作用机理。 The genus Streptomyces (Actinomycetes) is an important group of microbe. Most antibiotics known nowdays are discovered from species of Streptomyces. The fungi of the genus Chaetomium have attracted much attention because various kinds of secondary metabolites with diverse bioactivities have been found from them. Thus, the bioactive compounds from two strains of Streptomyces and the secondary metabolites of Chaetomium aureus were investigated. 1. Three compounds were isolated from the ethyl acetate extract of the fermentation broth of Streptomyces hygroscopicus. They are identified to be elaiophylin (1), nigericin (2), and antibiotic RK955A (3) on the basis of their spectroscopic data. Compounds 1-3 possess antibacterial activities against Staphyloccocus aureus. 2. It was found that the extract of the fermented broth of a strain of Actinomycetes could inhibit some tumor cel lines. Separation of the bioactive fraction led to the isolation of six compounds. They were characterized to be phenylacetamide (4), phenylpropylamide (5), trans-cinnamamide (6), 3- (N- (formylmethyl) acetamide) indole (7), guanylicacid (8), and guanosine (9). 3. From the fermented broth of Chaetomium aureus, 13 compounds were isolated for the first time. They were determined to be chaetomiumycin A (10), chaetomiumycin B (11), eugenetin (12), eugenitol (13), chaetoquadrin A (14), chaetoquadrin B (15), chaetoquadrin G (16), chaetoquadrin H (17), chaetochromin A (18), sterigmatocystin (19), O-methylsterigmatocystin (20), 3β-hydroxyergosta-5, 7, 22-triene (21) and peroxy-ergosterol (22). Compounds 10 and 11 are new ones. 4. Structure, biosynthesis, biological activity, and mechanisms of polyether antibiotics were reviewed.

The Development of a Marine Natural Product-based Antifouling Paint

Problems with tin and copper antifouling compounds have highlighted the need to develop new environmentally friendly antifouling coatings. Bacteria isolated from living surfaces in the marine environment are a promising source of natural antifouling compounds. Four isolates were used to produce extracts that were formulated into ten waterbased paints. All but one of the paints showed activity against a test panel of fouling bacteria. Five of the paints were further tested for their ability to inhibit the settlement of barnacle larvae, Balanus amphitrite, and algal spores of Ulva lactuca, and for their ability to inhibit the growth of U. lactuca. Two paints caused a significant decrease in the number of settled barnacles. One paint containing extract of Pseudomonas sp. strain NUDMB50-11, showed excellent activity in all assays. The antifouling chemicals responsible for the activity of the extract were isolated, using bioassay guided fractionation, and their chemical structures determined.

Methyleneimidazoline Complexes of Iridium, Rhodium, and Palladium from Selective C(sp(3))-H Bond Activation

Palladium, iridium, and rhodium complexes of 2-methyleneimidazolines have been synthesized by selective phosphine-assisted activation of the 2-methyl C-H bonds in 2-methylimidazolium compounds. Metallacycles of various sizes were obtained in the reaction of phosphine-tethered 2-methylimidazolium compounds and [{M(cod)X}(2)] (M = Rh or Ir cod = 1,5-cyclooctadiene: X = alkoxyl or Cl). representative complexes were characterized by X-ray crystallography. The selectivity for aliphatic C(sp(3))H versus aromatic C(sp(2))H activation could be adjusted by means of the steric bulk of the OR ligand, whereby a bulky, OR group favors activation of the 2-methyl C(sp(3))-H bond. Experimental results confirmed that a methyl C-H activation product (a seven-membered iridacycle) is the kinetic product, while the aryl C-H activation product (a six-membered iridacycle) is the thermodynamic product.

High resolution mass spectrometric alveolar proteomics: Identification of surfactant protein SP-A and SP-D modifications in proteinosis and cystic fibrosis patients

In the present study, one- and two-dimensional gel electrophoresis combined with high resolution Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) have been applied as powerful approaches for the proteome analysis of surfactant proteins SP-A and SP-D, including identification of structurally modified and truncation forms, in bronchoalveolar lavage fluid from patients with cystic fibrosis, chronic bronchitis and pulmonary alveolar proteinosis. Highly sensitive micro preparation techniques were developed for matrix-assisted laser desorption/ionization (MALDI) FT-ICR MS analysis which provided the identification of surfactant proteins at very low levels. Owing to the high resolution, FT-ICR MS was found to provide substantial advantages for the structural identification of surfactant proteins from complex biological matrices with high mass determination accuracy. Several protein bands corresponding to SP-A and SP-D were identified by MALDI-FT-ICR MS after electrophoretic separation by one- and two-dimensional gel electrophoresis, and provided the identification of structural modifications (hydroxy-proline) and degradation products.

Distribution of molluscan remains in the sediment of the Chukchi Sea and its vicinity, the Arctic

The result of an analysis of mollusca remains collected from the Chukchi Sea, Beaufort Sea and Bering Sea in the First Chinese National Arctic Research Expedition, from July to September, 1999 is presented. Seventeen species of mollusca have been identified, which belong to two classes: Bivalvia and Gastropoda. The compositions of the mollusca are very simple. According to the distribution pattern two groups may be distinguished among molluscan species. The Pan-Arctic and circumboreal group comprises Nuculana pernula, N.radiata, Nucula bellotii, Astarte montagui, Seripes groenlandicus, Macoma calcarea, M. moesta alaskana, Liocyrna fluctuosa, Mya pseudoarenaria and Turritella polaris. Three species, Cyclocardia crebricostata, Trichotrois coronata and Argobuccinum oregonense are components of the Pan-Arctic and Pacific boreal group. With regard to feeding habits, detritus feeders dominate. There are 7 species of detritus feeders, i.e., Nuculana pernula, N. radiata, Nucula bellotii, Macoma calcarea, M. moesta alaskana, Macoma sp. and Trichotropis coronata. Detritus feeders are dominant with regard to the numbers of species as well as to the frequency of occurrence. Macoma calcarea is the most abundant species.

Differences in the rDNA-bearing chromosome divide the Asian-Pacific and Atlantic species of Crassostrea (Bivalvia, Mollusca)

Karyotype and chromosomal location of the major ribosomal RNA genes (rDNA) were studied using fluorescence in situ hybridization (FISH) in five species of Crassostrea: three Asian-Pacific species (C. gigas, C. plicatula, and C. ariakensis) and two Atlantic species (C. virginica and C. rhizophorae). FISH probes were made by PCR amplification of the intergenic transcribed spacer between the 18S and 5.8S rRNA genes, and labeled with digoxigenin-11-dUTP. All five species had a haploid number of 10 chromosomes. The Atlantic species had 1-2 submetacentric chromosomes, while the three Pacific species had none. FISH with metaphase chromosomes detected a single telomeric locus for rDNA in all five species without any variation. In all three Pacific species, rDNA was located on the long arm of Chromosome 10 (10q)-the smallest chromosome. In the two Atlantic species, rDNA was located on the short arm of Chromosome 2 (2p)-the second longest chromosome. A review of other studies reveals the same distribution of NOR sites (putative rDNA loci) in three other species: on 10q in C. sikamea and C. angulata from the Pacific Ocean and on 2p in C. gasar from the western Atlantic. All data support the conclusion that differences in size and shape of the rDNA-bearing chromosome represent a major divide between Asian-Pacific and Atlantic species of Crassostrea. This finding suggests that chromosomal divergence can occur under seemingly conserved karyotypes and may play a role in reproductive isolation and speciation.

T-Muurolol Sesquiterpenes from the Marine Streptomyces sp M491 and Revision of the Configuration of Previously Reported Amorphanes

Two new sesquiterpenes, 15-hydroxy-T-muurolol (3d) and 11,15-dihydroxy-T-muurolol (3e), along with the plant cadinenes T-muurolol (3f) and 3 alpha-hydroxy-T-muurolol (3g), were isolated from the marine-derived Streptomyces sp. M491. Their absolute configuration was established via NMR spectroscopy and X-ray crystallography of 3-oxo-T-muurolol (3a), which was reisolated from this strain. In addition, the absolute configuration of further sesquiterpenes previously reported from this strain was revised. These products were tested for their cytotoxicity against 37 human tumor cell lines using the MTT method. Only 3d was cytotoxic against a range of human tumor cell lines with a mean IC50 of 6.7 mu g/mL.

Chinikomycins A and B: Isolation, structure elucidation, and biological activity of novel antibiotics from a marine Streptomyces sp isolate M045

In our screening of marine Streptomycetes for bioactive principles, two novel antitumor antibiotics designated as chinikomycins A (2a) and B (2b) were isolated together with manumycin A (1), and their structures were elucidated by a detailed interpretation of their spectra. Chinikomycins A (2a) and B (2b) are chlorine-containing aromatized manumycin derivatives of the type 64-pABA-2 with an unusual para orientation of the side chains. They exhibited antitumor activity against different human cancer cell lines, but were inactive in antiviral, antimicrobial, and phytotoxicity tests.

Changes in RNA, DNA, protein contents and growth of turbot Scophthalmus maximus larvae and juveniles

The growth potential of turbot Scophthalmus maximus larvae and juveniles was studied using nucleic acid-based indices and protein variables. The experiment was carried out from 4 to 60 days post hatching (dph). A significant increase in instantaneous growth rate during metamorphosis and retarded growth rate during post-metamorphic phase were observed. Ontogenetic patterns of DNA, RNA and protein all showed developmental stage-specific traits. The RNA:DNA ratio decreased up to 12 dph, then increased rapidly till 19 dph and fluctuated until 35 dph followed by a decline to the end. The RNA:DNA ratio was positively correlated with growth rate of juveniles during the post-metamorphic phase, whereas this ratio was not a sensitive indicator of growth during the pre-metamorphic phase and metamorphosis. The protein:DNA ratio showed a similar tendency to the RNA:DNA ratio. Changes of DNA content and protein:DNA ratio revealed that growth of S. maximus performed mainly by hyperplasia from 4 to 12 dph and hypertrophy until 21 dph during the pre-metamorphic larval phase. Growth was dominantly hypertrophical from the early- to mid-metamorphosing phase and hyperplastic thereafter. The results show that the DNA content and protein:DNA ratio can evaluate growth rates of larval and juvenile S. maximus on a cellular level.

Amorphane sesquiterpenes from a marine Streptomyces sp.

The chemical investigation of the crude extract of the marine-derived Streptomyces sp. M491 yielded three new sesquiterpenes, namely, 10 alpha,11-dihydroxyamorph-4-ene (4), 10 alpha,15-dihydroxyamorph-4-en-3-one (6), and 5 alpha,10 alpha,11-trihydroxyamorphan-3-one (7). In addition, the known compounds 10 alpha-hydroxyamorph-4-en-3-one (2), o-hydroxyacetanilide, genistein, prunetin, and indole-3-carbaldehyde and the macrolide antibiotic chalcomycin A were identified. The structures were determined on the basis of spectroscopic analysis, especially 1D and 2D NMR data. This is the first report of these sesquiterpenes from bacteria.

Cloning, characterization, and molecular application of a beta-agarase gene from Vibrio sp strain V134

V134, a marine isolate of the Vibrio genus, was found to produce a new beta-agarase of the GH16 family. The relevant agarase gene agaV was cloned from V134 and conditionally expressed in Escherichia coli. Enzyme activity analysis revealed that the optimum temperature and pH for the purified recombinant agarase were around 40 degrees C and 7.0. AgaV was demonstrated to be useful in two aspects: first, as an agarolytic enzyme, the purified recombinant AgaV could be employed in the recovery of DNA from agarose gels; second, as a secretion protein, AgaV was explored at the genetic level and used as a reporter in the construction of a secretion signal trap which proved to be a simple and efficient molecular tool for the selection of genes encoding secretion proteins from both gram-positive and gram-negative bacteria.

Cloning, characterization, and molecular application of a beta-agarase gene from Vibrio sp strain V134

V134, a marine isolate of the Vibrio genus, was found to produce a new beta-agarase of the GH16 family. The relevant agarase gene agaV was cloned from V134 and conditionally expressed in Escherichia coli. Enzyme activity analysis revealed that the optimum temperature and pH for the purified recombinant agarase were around 40 degrees C and 7.0. AgaV was demonstrated to be useful in two aspects: first, as an agarolytic enzyme, the purified recombinant AgaV could be employed in the recovery of DNA from agarose gels; second, as a secretion protein, AgaV was explored at the genetic level and used as a reporter in the construction of a secretion signal trap which proved to be a simple and efficient molecular tool for the selection of genes encoding secretion proteins from both gram-positive and gram-negative bacteria.