碳/碳复合密封材料及其的制备方法

一种碳／碳复合密封材料及其制备方法，它是以石墨蠕虫为基体填料，短切碳纤维为增强剂，耐高温有机硅高温漆或ＦＢ树脂为粘结剂，经冷压成型后固化、半碳化或热压成型，半碳化工艺制得产品，具有耐高温、强度高、寿命长、耐腐蚀、回弹性好、工艺简单、成本低的特点。

Chandrananimycins A-C: Production of novel anticancer antibiotics from a marine Actinomadura sp isolate M048 by variation of medium composition and growth conditions

In our screening of marine actinomycetes for bioactive principles, three novel antibiotics designated as chandrananimycin A (3c), B (3d) and C (4) were isolated from the culture broth of a marine Actinomadura sp. isolate M045. The structures of the new antibiotics were determined by detailed interpretation of mass, 1 D and 2 D NMR spectra.

胶州湾海洋链霉菌抑菌活性筛选、2株抑菌活性菌株的鉴定及次级代谢产物的研究

本文对256株胶州湾海洋链霉菌进行了抑菌活性的筛选，并选取10株典型菌株进行化学筛选，获得2株有研究价值的菌株。通过大规模发酵，获得纯化的次级代谢产物，进行了结构解析。通过与其他5株活性菌株的16S rRNA基因序列比较，并结合生理生化、形态特征和培养特征分析，探讨了这两株菌的分类地位。 　　采用液体扩散法，选用金黄色葡萄球菌、大肠杆菌、绿脓杆菌、八叠球菌、隐球菌、白色念珠菌、Mucor miehei (TÜ 284)和Streptomyces viridochromogenes (TÜ57) 8株受试菌进行抑菌活性的筛选，结果22%的菌株显示出对至少一种受试菌具有抑制作用(抑菌圈Æ ³ 8 mm)。根据菌株的形态特征和抑菌活性特点，选择M024、M028、M042、M083、M086、M095、M097、M124、M134和M226 10株链霉菌进行化学筛选。考察了8种培养基和4种培养条件，结果发现菌株M095在Meat extract培养基、pH 6.5、28℃和95 r/min条件下，菌株M097在Meat extract培养基、pH 7.8、 28℃、95 r/min(条件Ⅰ)和M2+培养基、pH 7.8、 35℃、110 r/min(条件Ⅱ)条件下，可供进一步研究。 对菌株M095(24 L规模)和M097(Ⅰ为30 L规模，Ⅱ为14 L规模)进行发酵，采用乙酸乙酯提取和柱层析分离纯化次级代谢产物，通过ESI-MS、EI-MS、1H-NMR和13C-NMR等波谱解析，鉴定出次级代谢产物的结构。发现菌株M095产生一抑菌活性很强的化合物全霉素，首次证实该全霉素具有抑制丝状真菌的作用；菌株M097主要产生10个化合物，其中8个具有不同程度的生物活性，另外两个化合物中，Aloesaponaria Ⅱ为首次从微生物野生菌株(wild strain)中获得，化合物Cui D为一新结构的蒽醌类化合物。 经分子鉴定，初步认为本实验分离的7株活性海洋链霉菌分属于4个链霉菌类群，结合生理生化、形态特征和培养特征分析，认为菌株M095可能为灰色链霉菌的变种，M097可能为球孢类群中的一个新种。

四株海洋放线菌遗传转化体系的研究

作者所在的课题组，自1998年以来从胶州湾海泥中陆续分离了800株海洋放线菌，并从4株放线菌中分离出了12个新结构活性化合物。选择产生新颖抗肿瘤抗生素的海洋放线菌M045和M048，产全霉素的海洋放线菌M095和产蒽醌类化合物的海洋放线菌M097为研究材料，建立了海洋放线菌的遗传转化体系，为海洋放线菌的遗传工程操作及天然化合物组合生物合成奠定了基础。 （1）通过接合转移建立了菌株M045的遗传转化体系。用来源于蓝藻Anacystis nidulans UTEX625的别藻蓝蛋白基因验证了转化体系的有效性。通过PCR及基因组步移方法获得长度为1709bp的部分聚酮合成酶（PKS）基因，分析其同放射菌素基因具有同源性，利用基因中断插入失活该基因，但未获得突变株。因此尝试通过反向遗传学方法，克隆该菌株中新骨架抗肿瘤抗生素——中国霉素的生物合成基因簇，本研究已经构建了该菌株Fosmid基因组文库，对基因组文库的筛选工作正在进行中。 （2）利用PEG-介导的质粒pIJ702转化原生质体和接合转移两种方法均成功获得菌株M048的转化子，其中接合转移率高达10-4。菌株M048来源于高盐的海洋环境，维持原生质体所需渗透压与模式菌株—变铅青链霉菌（Streptomyces lividans）有很大差异，本研究对菌株M048原生质体形成和再生的各种因素进行了优化，获得了渗透压稳定剂蔗糖最佳浓度为0.4M。 质粒pIJ8600整合于菌株M048染色体上，对该转化株的抑菌活性、薄层层析（TLC）以及HPLC-MS进行了分析。结果表明，同野生菌株相比，该转化株对7种受试菌的抑菌活性显著增强，TLC显示差异的化合物条带，HPLC-MS显示化合物组分有差异。因此质粒pIJ8600的整合，引起菌株次级代谢产物生物合成途径的改变，使有抑菌活性的化合物大量累积。 从菌株M048染色体上克隆获得了1196bp的部分PKS基因，通过基因中断插入失活该基因，结果显示M048突变株次级代谢产物抑菌活性增强，HPLC分析发现显著差异。初步分析该PKS基因的中断使菌株体内某些生物合成途径受阻，而大量合成抗菌活性强的chandrananimycin C，或者产生了抑菌活性强的其它化合物。 （3）本研究成功建立了菌株M095的接合转移体系。M095/pIJ8600转化株的生物学活性分析并未发现差异，表明该菌株染色体上的整合位点（attB）是中性（neutral）的。通过PCR以及基因组步移的方法克隆获得了该菌株的部分糖基转移酶基因，该基因中断突变株对4株受试菌的抑菌活性增强，HPLC显示有差异，表明该糖基转移酶基因参与了菌株M095活性次级代谢产物的生物合成过程。 （4）对于菌株M097，用接合转移法成功获得了转化子。实现了别藻蓝蛋白基因的重组表达，并纯化了表达产物，体外试验表明其具有清除羟基自由基能力。结果表明来源于蓝藻的外源基因可以在海洋放线菌体内有效表达和正确折叠，初步验证了本研究所建立的海洋放线菌遗传转化体系的稳定性及有效性。对M097/pIJ8600转化株的生物学活性分析，未发现差异，表明该菌株染色体上的整合位点是中性的。 本论文首次将基因工程技术引入四株海洋放线菌，建立了海洋放线菌自身的基因转移系统，为利用基因工程技术改造海洋放线菌的天然化合物生物合成途径提供了方法。对部分PKS基因中断突变株的生物学活性及化学分析，初步揭示了通过遗传转化方法进行化合物组合生物合成的可行性。

青海高寒草甸土壤放线菌区系研究

2001～2002年从海北高寒草甸生态系统采集土样,用不同方法从中分离放线菌300余株,根据其形态和分类特征,分别归入小单孢菌属(Micromonospora)、诺卡氏菌属(Nocardia)、糖多孢菌属(Saccharopolyspora)、原小单孢菌属(Promicromonospora)和链霉菌属(Streptomyces),并将链霉菌归入7个类群.同时对230株中温菌和110株低温菌的部分酶活性及其对真菌和细菌的拮抗性进行了测定,发现链霉菌不仅具有许多酶活性,而且对真菌和细菌有拮抗性.

Biodiscovery of natural products from microbes associated with Irish coastal sponges

Marine sponges have been an abundant source of new metabolites in recent years. The symbiotic association between the bacteria and the sponge has enabled scientists to access the bacterial diversity present within the bacterial/sponge ecosystem. This study has focussed on accessing the bacterial diversity in two Irish coastal marine sponges, namely Amphilectus fucorum and Eurypon major. A novel species from the genus Aquimarina has been isolated from the sponge Amphilectus fucorum. The study has also resulted in the identification of an α–Proteobacteria, Pseudovibrio sp. as a potential producer of antibiotics. Thus a targeted based approach to specifically cultivate Pseudovibrio sp. may prove useful for the development of new metabolites from this particular genus. Bacterial isolates from the marine sponge Haliclona simulans were screened for anti–fungal activity and one isolate namely Streptomyces sp. SM8 displayed activity against all five fungal strains tested. The strain was also tested for anti–bacterial activity and it showed activity against both against B. subtilis and P. aeruginosa. Hence a combinatorial approach involving both biochemical and genomic approaches were employed in an attempt to identify the bioactive compounds with these activities which were being produced by this strain. Culture broths from Streptomyces sp. SM8 were extracted and purified by various techniques such as reverse–phase HPLC, MPLC and ash chromatography. Anti–bacterial activity was observed in a fraction which contained a hydroxylated saturated fatty acid and also another compound with a m/z 227 but further structural elucidation of these compounds proved unsuccessful. The anti–fungal fractions from SM8 were shown to contain antimycin–like compounds, with some of these compounds having different retention times from that of an antimycin standard. A high–throughput assay was developed to screen for novel calcineurin inhibitors using yeast as a model system and three putative bacterial extracts were found to be positive using this screen. One of these extracts from SM8 was subsequently analysed using NMR and the calcineurin inhibition activity was con rmed to belong to a butenolide type compound. A H. simulans metagenomic library was also screened using the novel calcineurin inhibitor high–throughput assay system and eight clones displaying putative calcineurin inhibitory activity were detected. The clone which displayed the best inhibitory activity was subsequently sequenced and following the use of other genetic based approaches it became clear that the inhibition was being caused by a hypothetical protein with similarity to a hypothetical Na+/Ca2+ exchanger protein. The Streptomyces sp. SM8 genome was sequenced from a fragment library using Roche 454 pyrosequencing technology to identify potential secondary metabolism clusters. The draft genome was annotated by IMG/ER using the Prodigal pipeline. The Whole Genome Shotgun project has been deposited at DDBJ/EMBL/GenBank under the accession AMPN00000000. The genome contains genes which appear to encode for several polyketide synthases (PKS), non–ribosomal peptide synthetases (NRPS), terpene and siderophore biosynthesis and ribosomal peptides. Transcriptional analyses led to the identification of three hybrid clusters of which one is predicted to be involved in the synthesis of antimycin, while the functions of the others are as yet unknown. Two NRPS clusters were also identified, of which one may be involved in gramicidin biosynthesis and the function of the other is unknown. A Streptomyces sp. SM8 NRPS antC gene knockout was constructed and extracts from the strain were shown to possess a mild anti–fungal activity when compared to the SM8 wild–type. Subsequent LCMS analysis of antC mutant extracts confirmed the absence of the antimycin in the extract proving that the observed anti–fungal activity may involve metabolite(s) other than antimycin. Anti–bacterial activity in the antC gene knockout strain against P. aeruginosa was reduced when compared to the SM8 wild–type indicating that antimycin may be contributing to the observed anti–bacterial activity in addition to the metabolite(s) already identified during the chemical analyses. This is the first report of antimycins exhibiting anti–bacterial activity against P. aeruginosa. One of the hybrid clusters potentially involved in secondary metabolism in SM8 that displayed high and consistent levels of gene–expression in RNA studies was analysed in an attempt to identify the metabolite being produced by the pathway. A number of unusual features were observed following bioinformatics analysis of the gene sequence of the cluster, including a formylation domain within the NRPS cluster which may add a formyl group to the growing chain. Another unusual feature is the lack of AT domains on two of the PKS modules. Other unusual features observed in this cluster is the lack of a KR domain in module 3 of the cluster and an aminotransferase domain in module 4 for which no clear role has been hypothesised.

Electron refluxing and K-shell line emission from Ti foils irradiated with sub-picosecond laser pulses at 527nm

We present data on emission of K-shell radiation from Ti foils irradiated with subpicosecond pulses of second harmonic radiation (527 nm) from the TARANIS laser system at intensities of up to 1018 Wcm-2. The data are used to demonstrate that a resonance absorption type mechanism is responsible for absorption of the laser light and to estimate fast electron temperatures of 30–60 keV that are in broad agreement with expectation from models of absorption for a steep density gradient. Data taken with resin-backed targets are used to demonstrate clear evidence of electron refluxing even at the modest fast electron temperatures inferred.

Improved diffusive gradients in thin films (DGT) measurement of total dissolved inorganic arsenic in waters and soils using a hydrous zirconium oxide binding layer

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A high-capacity diffusive gradients in thin films (DGT) technique has been developed for measurement of total dissolved inorganic arsenic (As) using a long shelf life binding gel layer containing hydrous zirconium oxide (Zr-oxide). Both As(III) and As(V) were rapidly accumulated in the Zr-oxide gel and could be quantitatively recovered by elution using 1.0 M NaOH for freshwater or a mixture of 1.0 M NaOH and 1.0 M H2O2 for seawater. DGT uptake of As(III) and As(V) increased linearly with deployment time and was independent of pH (2.0–9.1), ionic strength (0.01–750 mM), the coexistence of phosphate (0.25–10 mg P L–1), and the aging of the Zr-oxide gel up to 24 months after production. The capacities of the Zr-oxide DGT were 159 μg As(III) and 434 μg As(V) per device for freshwater and 94 μg As(III) and 152 μg As(V) per device for seawater. These values were 5–29 times and 3–19 times more than those reported for the commonly used ferrihydrite and Metsorb DGTs, respectively. Deployments of the Zr-oxide DGT in As-spiked synthetic seawater provided accurate measurements of total dissolved inorganic As over the 96 h deployment, whereas ferrihydrite and Metsorb DGTs only measured the concentrations accurately up to 24 and 48 h, respectively. Deployments in soils showed that the Zr-oxide DGT was a reliable and robust tool, even for soil samples heavily polluted with As. In contrast, As in these soils was underestimated by ferrihydrite and Metsorb DGTs due to insufficient effective capacities, which were likely suppressed by the competing effects of phosphate.

A coiled-coil-repeat protein 'Ccrp' in Bdellovibrio bacteriovorus prevents cellular indentation, but is not essential for vibroid cell morphology

Bdellovibrio bacteriovorus are small, vibroid, predatory bacteria that grow within the periplasmic space of a host Gram-negative bacterium. The intermediate-filament (IF)-like protein crescentin is a member of a broad class of IF-like, coiled-coil-repeat-proteins (CCRPs), discovered in Caulobacter crescentus, where it contributes to the vibroid cell shape. The B. bacteriovorus genome has a single ccrp gene encoding a protein with an unusually long, stutter-free, coiled-coil prediction; the inactivation of this did not alter the vibriod cell shape, but caused cell deformations, visualized as chiselled insets or dents, near the cell poles and a general 'creased' appearance, under the negative staining preparation used for electron microscopy, but not in unstained, frozen, hydrated cells. Bdellovibrio bacteriovorus expressing 'teal' fluorescent protein (mTFP), as a C-terminal tag on the wild-type Ccrp protein, did not deform under negative staining, suggesting that the function was not impaired. Localization of fluorescent Ccrp-mTFP showed some bias to the cell poles, independent of the cytoskeleton, as demonstrated by the addition of the MreB-specific inhibitor A22. We suggest that the Ccrp protein in B. bacteriovorus contributes as an underlying scaffold, similar to that described for the CCRP protein FilP in Streptomyces coelicolor, preventing cellular indentation, but not contributing to the vibroid shape of the B. bacteriovorus cells.

A tale of two bioprocesses

Bioprocesses use microorganisms or cells in order to produce and/or obtain some desired products. Nowadays these strategies appear as a fundamental alternative to the traditional chemical processes. Amongst the many advantages associated to their use in the chemical, oil or pharmaceutical industries, their low cost, easily scale-up and low environmental impact should be highlighted. This work reports two examples of bioprocesses as alternatives to traditional chemical processes used by the oil and pharmaceutical industries. In the first part of this work it was studied an example of a bioprocess based on the use of microorganisms in enhanced oil recovery. Currently, due to high costs of oil and its scarcity, the enhanced oil recovery techniques become very attractive. Between the available techniques the use of microbial enhanced oil recovery (MEOR) has been highlighted. This process is based on the stimulation of indigenous microorganisms or by the injection of microorganism consortia to produce specific metabolites and hence increase the amount of oil recovered. In the first chapters of this work the isolation of several microorganisms from samples of paraffinic Brazilian oils is described, and their tensioactive and biodegradability properties are presented. Furthermore, the chemical structures of the biosurfactants produced by those isolates were also characterized. In the final chapter of the first part, the capabilities of some isolated bacteria to enhance the oil recovery of paraffinic Brazilian oils entrapped in sand-pack columns were evaluated. In the second part of this work it was investigated aqueous two-phase systems or aqueous biphasic systems (ABS) as extractive strategies for antibiotics directly from the fermented broth in which they are produced. To this goal, several aqueous two-phase systems composed of ionic liquids (ILs) and polymers were studied for the first time and their phase diagrams were determined. The novel ATPS appear as effective and economic methods to extract different biomolecules or/and biological products. Thus, aiming the initial antibiotics extraction purpose it was studied the influence of a wide range of ILs and polymers in the aqueous two-phase formation ability, as well as their influence in the partitioning of several type-molecules, such as amino acids, alkaloids and dyes. As a final chapter it is presented the capacity of these novel systems to extract the antibiotic tetracycline directly from the fermented broth of Streptomyces aureofaciens.

O terrível nascimento da beleza: a criação literária em diversos autores

De onde brota a inspiração para baladas de amor e canções de guerra, lendas e narrativas, tragédias e comédias? Ao longo de séculos, escritores e leitores interrogaram-se acerca do nascimento da beleza. Neste artigo, abordo essa questão intrigante, em quatro etapas: a) Examino algumas personificações criadas por Hesíodo, Homero, Luís de Camões e Federico García Lorca para descreverem a inspiração; b) Exploro as estratégias utilizadas por Samuel Coleridge, Salvador Dalí e William Burroughs, para penetrar no reino da fantasia, o inconsciente; c) Apresento as explicações científicas propostas por Sigmund Freud, Carl Jung e Robert Sperry para o impulso criativo; d) Para concluir, menciono as razões que levaram Fernando Pessoa, Eugénio de Andrade e Emily Dickinson a desconfiarem da musa inspiradora, preferindo o esforço que corrige a emoção e gera a obra de arte. Seguindo uma perspectiva comparada, o meu objectivo é mostrar diferentes formas de perceber a criatividade literária. Para tanto, recorro ao trabalho dos escritores e cientistas atrás mencionados e, naturalmente, à minha opinião.

L'Écho de Paris

1892/10/04 (Numéro 3060).