The second anti-lipopolysaccharide factor (EsALF-2) with antimicrobial activity from Eriocheir sinensis

The anti-lipopolysaccharide factor CALF) is a small basic protein that can bind and neutralize lipopolysaccharide (LPS), mediating degranulation and activation of an intracellular coagulation cascade. In the present study, cDNA of the second Eriocheir sinensis ALF (designated as EsALF-2) was cloned and the full-length cDNA of EsALF-2 was of 724 bp, consisting of an open reading frame (ORF) of 363 bp encoding a polypeptide of 120 amino acids. The deduced amino acid of EsALF-2 shared 82% similarity with EsALF-1 from E. sinensis and about 53-65% similarity with ALFs from other crustaceans. The potential tertiary structures of EsALF-1 and EsALF-2 contained two highly conserved-cysteine residues to define the LPS binding site, but the N-terminal of EsALF-1 formed a single additional alpha-helix compared to EsALF-2, implying that EsALF-1 and EsALF-2 might represent different biological functions in E. sinensis. The mRNA transcript of EsALF-2 was detected in all examined tissues of healthy crabs, including haemocytes, hepatopancreas, gill, muscle, heart and gonad, which suggested that EsALF-2 could be a multifunctional molecule for the host immune defense responses and thereby provided systemic protection against pathogens. The mRNA expression of EsALF-2 was up-regulated after Listonelln anguillarum and Pichia pastoris challenge and the recombinant protein of EsALF-2 showed antimicrobial activity against L. anguillarum and P. pastoris. indicating that EsALF-2 was involved in the immune defense responses in Chinese mitten crab against L. anguillarum and P. pastoris. These results together indicated that there were abundant and diverse ALFs in E. sinensis with various biological functions and these ALFs would provide candidate promising therapeutic or prophylactic agents in health management and diseases control of crab aquaculture. (C) 2010 Elsevier Ltd. All rights reserved.

Novel antifouling and antimicrobial compound from a marine-derived fungus Ampelomyces sp.

In this study, using a bioassay-guided isolation and purification procedure, we obtained 3-chloro-2,5-dihydroxybenzyl alcohol from a marine-derived Ampelomyces species that effectively inhibited larval settlement of the tubeworm Hydroides elegans and of cyprids of the barnacle Balanus amphitrite. The inhibitive effect on larval settlement was nontoxic and the EC50 of 3-chloro-2,5-dihydroxybenzyl alcohol ranged from 3.19 mu g ml(-1) to 3.81 mu g ml(-1) while the LC50 was 266.68 lambda g ml(-1) for B. amphitrite cyprids; EC50 ranged from 0.67 mu g ml(-1) to 0.78 mu g ml(-1), and LC50 was 2.64 mu g ml(-1) for competent larvae of H. elegans, indicating that inhibitive effect of this compound was nontoxic. At a concentration of 50 mu g per disc, this compound showed strong inhibitive effects on the growth of 13 out of 15 marine bacterial species tested in disc diffusion bioassay. Overall, the high inhibitory activities against bacteria and larval settlement as well as the non- or low-toxic nature of this compound to the barnacle and polychaete larvae suggest this compound could be a potent antifoulant and/or antibiotic.

Extracellular hydrolytic enzyme screening of culturable heterotrophic bacteria from deep-sea sediments of the Southern Okinawa Trough

The Southern Okinawa Trough is an area of focused sedimentation due to particulate matter export from the shelf of the East China Sea and the island of Taiwan. In order to understand the geomicrobiological characteristics of this unique sedimentary environment, bacterial cultivations were carried out for an 8.61 m CASQ core sediment sample. A total of 98 heterotrophic bacterial isolates were characterized based on 16S rRNA gene phylogenetic analysis. These isolates can be grouped into four bacterial divisions, including 13 genera and more than 20 species. Bacteria of the gamma-Proteobacteria lineage, especially those from the Halomonas ( 27 isolates) and Psychrobacter ( 20 isolates) groups, dominate in the culturable bacteria assemblage. They also have the broadest distribution along the depth of the sediment. More than 72.4% of the isolates showed extracellular hydrolytic enzyme activities, such as amylases, proteases, lipases and Dnases, and nearly 59.2% were cold-adapted exoenzyme-producers. Several Halomonas strains show almost all the tested hydrolases activities. The wide distribution of exoenzyme activities in the isolates may indicate their important ecological role of element biogeochemical cycling in the studied deep-sea sedimentary environment.

Marine bacteria associated with marine macroorganisms: the potential antimicrobial resources

In order to explore marine microorganisms with medical potential, marine bacteria were isolated from seawater, sediment, marine invertebrates and seaweeds collected from different coastal areas of the China Sea. The antimicrobial activities of these bacteria were investigated. Ethyl acetate extracts of marine bacterial fermentation were screened for antimicrobial activities using the method of agar diffusion. The results showed that 42 strains of the isolates have antimicrobial activity. The proportion of active bacteria associated with marine invertebrates (20%) and seaweeds (11%) is higher than that isolated from seawater (7%) and sediment (5%). The active marine bacteria were assigned to the genera Alteromonas, Pseudomonas, Bacillus and Flavobacterium. The TLC autobiographic overlay assay implied that the antimicrobial metabolites produced by four strains with wide antimicrobial spectrum were different. Due to a competitive role for space and nutrient, the marine bacteria associated with marine macroorganisms (invertebrates and seaweeds) could produce more antibiotic substances. These marine bacteria were expected to be potential resources of natural antibiotic products.

Screening of surfactants for harmful algal blooms mitigation

Screening experiments were conducted in order to find promising synthetic surfactants for harmful algal blooms (HABs) mitigation. The chemically synthesized surfactant cocamidopropyl betaine (CAPB) showed characteristics of relatively high inhibition efficiency, high biodegradability and low cost. The motility inhibition ratios of 10 mg/L CAPB on Cochlodinium polykrikoides and Alexandrium tamarense were about 60% after 5 min. The biodegradation test indicated that the half-life of CAPB in seawater was shorter than one day and 90% was biodegraded after five days under the initial concentration of 100 mg/L at 25degreesC. Further cell lysis experiments revealed the selective lysis effect of CAPB on different HAB organisms. More than 90% of C. polykrikoides lysed at the concentration of 10 mg/L CAPB after 24 h and at 15 mg/L CAPB after 4 h, whereas the lysis effect of CAPB on A. tamarense was slight, no more than 10% after 2 h interaction with 50 mg/L CAPB. This research provided preliminary data for CAPB as a candidate in harmful algal blooms mitigation and pointed out unresolved problems for its practical application in the meantime. (C) 2003 Elsevier Ltd. All rights reserved.

Toxin-screening and identification of bacteria isolated from highly toxic marine gastropod Nassarius semiplicatus

Bacteria isolated from a highly toxic sample of gastropod Nassarius semiplicatus in Lianyungang, Jiangsu Province in July 2007, were studied to probe into the relationship between bacteria and toxicity of nassariid gastropod. The toxicity of the gastropod sample was 2 x 10(2) mouse unit (MU) Per gram Of tissue (wet weight). High concentration of tetrodotoxin (TTX) and its analogues (TTXs) were found in the digestive gland and muscle of the gastropod, using high performance liquid chromatography coupled with mass chromatography (LC-MS). Bacterial strains isolated from the digestive gland were cultured and screened for TTX with a competitive ELISA method. Tetrodotoxin was detected in a proportion of bacterial strains, but the toxin content was low. Partial 16S ribosomal DNA (rDNA) of the TTX-producing strains was then sequenced and compared with those published in the GenBank to tentatively identify the toxic strains. It was found that most of the toxic strains were closely affiliated with genus Vibrio, and the others were related to genus Shewanella, Marinomonas, Tenacibaculum and Aeromonas. These findings suggest that tetrodotoxin-producing bacteria might play an important role in tetrodotoxin accumulation/production in N. semiplicatus. (C) 2008 Elsevier Ltd. All rights reserved.

Antimicrobial activity of hydroxylbenzenesulfonailides derivatives of chitosan, chitosan sulfates and carboxymethyl chitosan

Chitosan, carboxymethyl chitosan (CIVICS) and chitosan sulfates (CSS) with different molecular weight were modified by reacting with 4-hydroxyl-5-chloride-1,3-benzene-disulfo-chloride or 2-hydroxyl-5-chloride-1,3 -benzene-disulfo-chloride to give 12 kinds of new hydroxylbenzenesulfonailides derivatives of them. The preparation conditions of the derivatives were discussed in this paper, and their structures were characterized by FT-IR and C-13 NMR spectroscopy. The solubility of the derivatives was measured in the experiment. In addition, their antimicrobial activities against four bacteria and five crop-threatening pathogenic fungi were tested in the experiment. Besides, the rule and mechanism of their antibacterial activities were discussed in this paper. (C) 2009 Published by Elsevier B.V.

Screening marine algae from China for their antitumor activities

Thirty-nine species of marine algae collected from the coast of China were screened for their antitumor activities, and eight species Leathesia difformes, Polysiphonia urcedata, Scytosiphon lomentarius, Gloiopeliis furcata, Punctaria latifolia, Symphyocladia latiuscula, Rhodomela confervoides and Ulva pertusa showed potent cytotoxic activities. Three, Rhodomela confervoides, Scytosiphon lomentarius and Gloiopeliis furcata, were used for further investigation. More than 30 compounds were isolated and purified, and 14 bromophenols, 1 steroid and 1 carotene were identified by advanced spectroscopic methods including IR, MS, and NMR techniques. Amongst the 16 identified compounds, 7 showed vigorously selective activities against KB, Bel7402 and A549 cancer cells, and 6 bromophenols were new compounds.

Synthesis of acyl thiourea derivatives of chitosan and their antimicrobial activities in vitro

Three different acyl thiourea derivatives of chitosan (CS) were synthesized and their structures were characterized by FT-IR spectroscopy and elemental analysis. The antimicrobial behaviors of CS and its derivatives against four species of bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Sarcina) and four crop-threatening pathogenic fungi (Alternaria solani, Fusarium oxysporum f. sp. vasinfectum, Colletotrichum gloeosporioides (Penz.) Saec, and Phyllisticta zingiberi) were investigated. The results indicated that the antimicrobial activities of the acyl thiourea derivatives are much better than that of the parent CS. The minimum value of MIC and MBC of the derivatives against E coli was 15.62 and 62.49 mu g/mL, respectively. All of the acyl thiourea derivatives had a significant inhibitory effect on the fungi in concentrations of 50 - 500 mu g/mL; the maximum inhibitory index was 66.67%. The antifungal activities of the chloracetyl thiourea derivatives of CS are noticeably higher than the acetyl and benzoyl thiourea derivatives. The degree of grafting of the acyl thiourea group in the derivatives was related to antifungal activity; higher substitution resulted in stronger antifungal activity. (c) 2007 Elsevier Ltd. All rights reserved.

Screening and analysis of biologically active compounds in Angelica sinensis by molecular biochromatography

A novel strategy for the screening and analysis of biologically active compounds in traditional Chinese medicine by molecular biochromatography is proposed. Molecular biochromatography with human serum albumin (HSA) immobilized on silica as stationary phase was used to screen and analyse the bioactive compounds in the typical Chinese medicine of Angelica sinensis (Oliv.) Diels. Ten peaks showed retention on this column, which is based on their affinity for HSA. Ferulic acid and liguistilide were identified as the principal active components, which agrees very well with the results in the literature. A quality control method was also developed based on the simultaneous determination the concentrations of ferulic acid and liguistilide in solutions of Angelica sinensis (Oliv.) Diels extracted with water and methanol. It was observed that the concentrations of ferulic acid and liguistilide in solution extracted with methanol were 2 and 53 times higher, respectively, than those with water. It was shown that molecular biochromatography is an effective way of analysing and screening biologically active compounds in traditional Chinese medicine.

High-throughput screening of HZSM-5 supported metal-oxides catalysts for the coupling of methane with CO to benzene and naphthalene

High-throughput screening of HZSM-5 supported metal-oxides catalysts were carried out for the coupling reaction of methane with CO to aromatics in a multi-stream reactor system. Zn/HZSM-5 and Mo/HZSM-5 were observed to be rather effective for the catalytic formation of aromatics from the coupling reaction of methane with CO. Temperature-programmed reaction has further proven the efficiency of the coupling of methane and CO over Zn/HZSM-5 catalyst. The results were also validated in a conventional fixed-bed reactor coupled with GC. The results propose that the coupling methane with CO toward benzene and naphthalene can be catalyzed by Zn/HZSM-5 at 500 ° C. Both methane and CO are needed for the formation of reactive coke on the catalyst, and the reactive coke may be the initial product in the producing of hydrocarbons. © 2005 Elsevier B.V. All rights reserved.

An in silico approach for screening flavonoids as P-glycoprotein inhibitors based on a Bayesian-regularized neural network

P-glycoprotein (P-gp), an ATP-binding cassette (ABC) transporter, functions as a biological barrier by extruding cytotoxic agents out of cells, resulting in an obstacle in chemotherapeutic treatment of cancer. In order to aid in the development of potential P-gp inhibitors, we constructed a quantitative structure-activity relationship (QSAR) model of flavonoids as P-gp inhibitors based on Bayesian-regularized neural network (BRNN). A dataset of 57 flavonoids collected from a literature binding to the C-terminal nucleotide-binding domain of mouse P-gp was compiled. The predictive ability of the model was assessed using a test set that was independent of the training set, which showed a standard error of prediction of 0.146 +/- 0.006 (data scaled from 0 to 1). Meanwhile, two other mathematical tools, back-propagation neural network (BPNN) and partial least squares (PLS) were also attempted to build QSAR models. The BRNN provided slightly better results for the test set compared to BPNN, but the difference was not significant according to F-statistic at p = 0.05. The PLS failed to build a reliable model in the present study. Our study indicates that the BRNN-based in silico model has good potential in facilitating the prediction of P-gp flavonoid inhibitors and might be applied in further drug design.