Design,synthesis, characterization,antibacterial and antifungal activities of a novel class of 5,7-diaryl-4,4-dimethyl-4,5,6,7-tetrahydropyridino[3,4-d]-1,2,3-selenadiazoles

Compound 26 is more potent against Escherichia coli. and 24 is more active against Staphylococcus aureus, β-Heamolytic streptococcus, Vibreo cholerae, Salmonella typhii, and Shigella flexneri than the standard drug ciprofloxacin. Moreover, of all the compounds tested, 26 is more effective against Aspergillus flavus and Mucor, than the standard drug fluconazole.     

Antibacterial Agents in Mediterranean Finfish Farming: A Synopsis of Drug Pharmacokinetics in Important Euryhaline Fish Species and Possible Environmental Implications

The literature pertaining to the use of registered antibacterial agents in Mediterranean finfish farming is reviewed, with an emphasis on the Greek fish-farming industry. This review provides a scientific resource dedicated to the design of future antibacterial dosing regimes in Mediterranean fish farming, where insufficient supporting information is currently available. This paper addresses the paucity in knowledge concerning pharmacokinetics and the efficacy and environmental impact of commonly used antibacterials needed to direct future research and promote good practices in the euryhaline fish farming industry. Several registered antibacterials are currently available for combating bacterial infections, including tetracyclines, (fluoro) quinolones, potentiated sulfa, penicillin and chloramphenicol derivatives. Based on the available data, oxytetracycline (OTC) and quinolone drugs (oxolinic acid – OA and flumequine – FLU) are the most widely used in Mediterranean aquaculture. As a result these drugs have received the most extensive studies, whereas, there is considerable paucity of reliable data on pharmacokinetic and the depletion characteristics of other drugs used, particularly potentiated sulfa, penicillin derivatives and florfenicol. We find there is incomplete data on drug efficacy and minimum inhibitory concentrations (MIC) for common antibacterials used against the major bacterial pathogens of Mediterranean fish species. Furthermore, a considerable lack of data on environmental drug concentrations around Mediterranean fish farms was also identified, highlighting the need for more extensive environmental studies to monitor contamination in environmental components i.e., water and sediment, and in non-target species (flora and fauna). Prudent selection and use of antibacterials can encourage lower dosage applications, enhance treatment efficacy, and help to minimize contamination of the environment. Selection of readily bioavailable drugs which have low environmental persistence, low aquatic toxicity and high antibacterial efficacy is advised, to reduce potential losses to the environment and associated toxic effects on target species and the development of bacterial resistance. Lack of present data made it impossible to provide thorough and accurate guidance on selection and use of antibacterials and approaches for minimizing environmental impacts for the treatment of major euryhaline aquaculture species.     

柞蚕抗菌肽D中精氨酸、赖氨酸和色氨酸等氨基酸残基的化学修饰

用不同的化学试剂修饰了柞蚕抗菌肽D分子中的色氨酸、精氨酸和赖氨酸等氨基酸残基。NBS修饰抗菌肽D,以及氨肽酶M对抗菌肽D作用的结果表明色氨酸残基对抗菌肽D抑制E.coli D31的作用影响不大。CHD和MLH对精氨酸和赖氨酸残基的修饰,导致抗菌肽D失去抑制E.coli的作用,但可逆地消除CHD和MLH的修饰作用后,抗菌肽D恢复了对E.coli D31的抑菌作用。这些结果初步认为,抗菌肽D抑菌作用与分子中的荷电性有关,改变了分子的电荷,也就同时失去了其抑菌功能。 此外,对精氨酸残基修饰的结果还表明,抗菌肽D的免疫原性与精氨酸残基有关。但是,抗菌肽D的免疫决定簇与其生物活性中心并不完全平行。     

光枝勾儿茶内生真菌多样性及抑菌活性研究

为探索贵州苗药光枝勾儿茶内生真菌类群特征、分布部位及其抑菌活性,该研究采用传统方法对贵州省贵阳市和黔西市光枝勾儿茶内生真菌进行分离,并基于分子生物学及统计学对其分类地位进行鉴定及多样性评价,最后通过微量肉汤倍比稀释法筛选具有抑菌活性的菌株。结果表明:(1)从光枝勾儿茶中分离到191 株内生真菌,隶属于3 个门5 个纲10 个目15 个科19 个属,优势属为叶点霉属(Phyllosticta)、间座壳属(Diaporthe)、葡萄座腔菌属(Botryosphaeria)和刺盘孢属(Colletotrichum)。(2)黔西光枝勾儿茶内生真菌香农-维纳多样性指数(H''_Q=2.112)较贵阳(H''_G=1.801)高,索伦森相似性指数Cs_G-Q为0.923,不同组织香农-维纳多样性指数为茎(H''_S=2.004)>根(H''_R=1.764)>叶(H''_L=1.654)>果实(H''_F=1.473),茎和叶内生真菌的索伦森相似性最高(Cs_S-L=0.667)。(3)筛选出的21株内生真菌对供试菌大肠杆菌(Escherichia coli)、金黄色葡萄球菌(Staphylococcus aureus)和沙门氏菌(Salmonella enterica)具有抑菌效果,其中Diaporthe sp. QX4G6对大肠杆菌、金黄色葡萄球菌和沙门氏菌的最小抑菌浓度分别为12.5、6.25、12.5 mg·mL^-1,最小杀菌浓度分别为12.5、6.25、12.5 mg·mL^-1。以上研究结果揭示了光枝勾儿茶蕴藏丰富的内生真菌资源,不同地区及组织内生真菌类群组成有差异,多个分离菌株具有抗菌活性,为光枝勾儿茶内生真菌天然抗菌药物或药源研发奠定了基础。     

Preparation and Characterization of a Silk Fibroin/Polyurethane Fiber Blend Membrane Containing Actinomycin X2 with Excellent Mechanical Properties and Enhanced Antibacterial Activities

Development of suitable antimicrobial biomaterials for hygienic wound dressing and healing is an important requirement for medical application. Durable mechanical properties increase the application range of biomaterial in different environmental and biological conditions. Due to the inherent brittleness of silk fibroin (SF), polyurethane fiber (PUF) was used to modify SF containing actinomycin X2 (Ac.X2) to prepare silk fibroin@actinomycin X₂/polyurethane fiber (ASF/PUF) blend membranes. The ASF/PUF blend membrane was developed by solution casting method. Incorporation of PUF improved the flexibility of material and introduction of Ac.X2 has increased antibacterial activity of materials. Excellent mechanical properties (tensile strength up to 25.7 MPa and elongation at break up to 946.5 %) of 50 % SF+50 % PUF blend membrane were proved by tensile testing machine. FT-IR spectra, TGA, contact angle and DMA were tested to prove the blend membrane's physico-chemical characteristics. ASF/PUF blend membrane displayed satisfactory antibacterial activity against S. aureus, and the cytotoxicity tests showed that the blend membrane has better biosafety compared to directly applied Ac.X2 in soluble form. These results suggest that the modification of SF through PUF for development of flexible antibacterial membranes has great potential application value in the field of silk-like material fabrication.     

Synthesis of New Bis(pyrazolo[1,5-a]pyrimidines) Linked to Different Spacers as Potential MurB Inhibitors

An efficient protocol was adopted to efficiently prepare three new series of bis(pyrazolo[1,5-a]pyrimidines) linked to different spacers. The new bis(pyrazolo[1,5-a]pyrimidines) were prepared in 80–90 % yields by reacting the respective bis(enaminones) and 4-(4-substituted benzyl)-1H-pyrazole-3,5-diamines in pyridine at reflux temperature for 5–7 h. The new products showed a wide spectrum of antibacterial activity against six different bacterial strains. In general, propane- and butane-linked bis(pyrazolo[1,5-a]pyrimidines), which are attached to 3-(4-methyl- or 4-methoxybenzyl) units, had the best antibacterial activity with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values up to 2.5 and 5.1 μM, respectively. Additionally, the previous products demonstrated promising MurB inhibitory activity with IC₅₀ values up to 7.2 μM.     

Antibacterial Compound Isolation and Characterization from the Plant Cynotis axillaris Schult

A novel flavone glycoside was isolated from the methanolic extract of Cynotis axillaris Schult. Various analysis and characterization techniques were used to determine its structure and properties. The compound exhibited a melting point range of 231–232 °C and had a molecular formula of C₂₇H₃₀O₁₄. Several spectral characterization techniques were employed to establish the isolated compound's structure. These included UV-visible spectroscopy, FT-IR, LC-ESI-MS, and NMR spectroscopy. Based on these analyses, the structure of the isolated compound was determined to be 5,7,4’-trihydroxyflavone-8-α-L-rhamnopyranoside-4’-O-β-D-galactopyranosyl. This structure indicates that it is a flavone glycoside consisting of a flavone (5,7,4’-trihydroxyflavone) moiety attached to a sugar molecule (galactopyranosyl) at position 4’, which further bears a rhamnose group at position 8 of the flavone. In addition, to the structural characterization, the compound also demonstrated significant antibacterial efficacy against various bacterial pathogens, including Gram-positive bacteria such as Bacillus subtilis MTCC441 and Gram-negative bacteria such as Escherichia coli MTCC1098, Proteus vulgarize MTCC426, and Salmonella Typhimurium MTCC3224. The antimicrobial activity was evaluated by measuring the zone of inhibition in millimetres, which provides an indication of the compound's ability to inhibit bacterial growth. The study successfully identified and characterized a novel flavone glycoside from Cynotis axillaris Schult. and its antimicrobial activity.     

Purification of antibacterial attacins induced in Hyalophora cecropia pupae immunized with Enterobacter cloacae C7-501 using ion-exchange chromatography,hydrophobic interaction chromatography,and Rotofor® isoelectric focusing

Hyalophora cecropia pupae were infected by Enterobacter cloacae C7-501 to induce antibacterial attacins for purification. The induction of attacins in immunized pupae was confirmed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Ion-exchange chromatography (IEC), hydrophobic interaction chromatography (HIC), and Rotofor® isoelectric focusing (ISEF) were applied to isolate attacins from the hemolymph. IEC separated attacins from most hemolymph proteins, but the fractions containing attacins also had other proteins of 20 and 64 kDa in length. In IEC, attacin was eluted with ~0.2 M NaCl. The best conditions for IEC were pH 9, flow rate of 2 mL/min, with step elution (0.025, 0.05, 0.075, 0.1, 0.2, 0.4 and 1.0 M NaCl). In HIC, most other proteins were eluted with the ammonium persulfate treatment. HIC isolated attacin proteins under hydrophobic conditions, at ~50% EtOH. However, the fraction with attacins also contained other proteins. The Rotofor® ISEF produced fractions containing attacins at isoelectric points ranging between 5.7 and 8.3. However, non-specific proteins were detected in the fraction samples, and the recovery of attacins was low. The purification efficiency of ISEF was lower than IEC and HIC. In this study, the expression of attacins was induced in H. cecropia pupae infected with E. cloacae C7-501, and attacins could be purified by IEC and ISEF. Overall, IEC provided better separation of attacins from the hemolymph of H. cecropia pupae immunized with E. cloacae bacteria than HIC and Rotofor® ISEF.     

20-羟基蜕皮酮对蓖麻蚕蛹体液免疫的调节作用(英)

本研究指出20—羟基蜕皮酮(20-OHE)参加蓖麻蚕蛹对大肠杆菌的体液免疫反应。20-OHE的作用方式是多方面的,包括提高血淋巴蛋白质含量,产生抗菌蛋白,增加溶菌酶活性,和激活原酚氧化酶系统。这表明多个免疫控制系统参与蓖麻蚕蛹体液免疫反应的可能性。