栉孔扇贝血淋巴中酯酶活性及其性质   总被引：5，自引：2，他引：5       下载免费PDF全文

孙虎山  王宜艳  王慧丽 《中国水产科学》2006,13(1):39-44

采用紫外分光光度法测定栉孔扇贝（Chlamysfarreri）血淋巴中酯酶的活性，并研究底物、抑制剂、激活剂、温度、pH对酯酶活力的影响及酶的热稳定性。结果表明，栉孔扇贝血清与血细胞中均存在酯酶，且血细胞中的酶活力高于血清。血清与血细胞中酯酶的最适作用底物有所不同，血清中为α-醋酸萘酯，而血细胞中为α-丁酸萘酯。当以α-醋酸萘酯为底物时，血清中酯酶的最适温度为45℃，最适pH值为7．5；以α-丁酸萘酯为底物时，血清中酯酶的最适温度为40℃，最适pH值为8．0。以α-醋酸萘酯及α-丁酸萘酯为底物分别测定酶的热稳定时，酶活力变化相似，在20℃时活力最高，而后缓慢下降。栉孔扇贝血淋巴中酯酶属中温型中性酶类，低温下较稳定，底物专一性不强，血清中的酯酶可能来自血细胞，该酶在贝类的免疫防御中町发挥重要的作用。  相似文献   

Intestinal phytase I: Detection and preliminary characterization of activity in the intestinal brush border membrane of hybrid striped bass Morone saxatilis × M. chrysops     

L.E. Ellestad  R. Angel  J.H. Soares Jr. 《Fish physiology and biochemistry》2002,26(3):249-258

While numerous studies have evaluated intestinal phytase activity in terrestrial monogastric species, little work has been conducted investigating the enzyme's activity in finfish. This experiment was conducted to determine if hybrid striped bass Morone saxatilis × M. chrysops possess intestinal phytase activity, and to perform a preliminary characterization of this activity in terms of pH, metal ion dependence and substrate kinetics. Hybrid bass do exhibit low levels of intestinal phytase activity. The activity has an acidic pH optimum between 3.5 and 4.5. Low concentrations of Mn²⁺ slightly enhance this activity. The divalent cations Mg²⁺ and Zn²⁺ were shown to either have no effect on the enzyme activity or to be inhibitory, particularly at high concentrations. The present results indicate that intestinal phytase activity in hybrid bass does follow Michaelis-Menten kinetics, with estimated K_m and V_max values of 2.5 mM phytate and 4.8 units mg⁻¹ protein, respectively. The physiologic significance of the enzyme's presence in hybrid striped bass is questionable due to the low activity as compared to terrestrial monogastrics, the acidic pH optimum and the low affinity the enzyme appears to have for phytate. These observations also raise the question of whether the intestinal phytase activity detected in hybrid bass is merely a manifestation of non-specific acid phosphatase activity. Further investigation is needed to determine the practical significance of phytase activity in hybrid bass in terms of phytate phosphorus utilization. Additional experiments should also be conducted which evaluate intestinal phytase activity in other important aquacultured finfish species. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Effect of shrimp head protein hydrolysates on the state of water and denaturation of fish myofibrils during dehydration   总被引：1，自引：0，他引：1  

Yaowalux?Ruttanapornvareesakul  Misako?Ikeda  Kenji?HaraEmail author  Kazufumi?Osako  Orawan?Kongpun  Yukinori?Nozaki 《Fisheries Science》2005,71(1):220-228

ABSTRACT:   To utilize fisheries waste products as food materials with functional properties, shrimp head protein hydrolysates (SHPH) from three species of shrimp, that is, Northern pink shrimp ( Pandalus eous ), Endeavour shrimp ( Metapenaeus endeavouri ) and Black tiger shrimp ( Penaeus monodon ), were produced by enzymatic hydrolysis using endopeptidase derived from Bacillus subtilis and exopeptidase derived from Aspergillus oryzae at a level of 0.1% (w/w). SHPH were rich in protein (90–91%) and amino acids (71–84%) but little fat (0.01–0.02%). The average molecular weight of SHPH was 300–1400. The effect of 5% SHPH (dry basis) addition on the state of water and denaturation of lizard fish myofibrils (Mf) during the dehydration process was evaluated by the desorption isotherm and the Ca-ATPase activity, and compared with the effect of sodium glutamate (Na-Glu). SHPH decreased the water activity and the Ca-ATPase inactivation, and increased monolayer sorbed water and multilayer sorbed water of Mf, although these effects of SHPH were smaller than those of Na-Glu. These findings suggest that the SHPH suppressed dehydration-induced denaturation of myofibrillar protein by stabilizing the hydrated water surrounding myofibrils.  相似文献   

GST-MtDef4融合蛋白的原核表达及体外抑菌活性的检测     

景晓辉  吴伦英  沈雁  赵辉  吴琳 《热带作物学报》2014,35(4):718-723

为研究苜蓿(Medicago truncatula)防卫素基因MtDef4的抑菌功能,以含有该基因片段的质粒pAND-MtDef4为模板,扩增出相应的目的基因,测序正确后将MtDef4基因片段连接到带有GST标签的原核表达载体pGEX6P-1中,转化大肠杆菌TransB(DE3),经IPTG诱导,Glutathione Sepharose 4B亲和纯化,通过SDS-PAGE电泳及Western blot确定融合蛋白的表达。体外抑菌试验表明,MtDef4能够抑制病原真菌Corynespora cassiicola而非Collectotrichum gloeosporioides的生长。本研究结果可为进一步培育转基因橡胶抗病品种奠定基础。  相似文献   

Aaptamine Derivatives with Antifungal and Anti-HIV-1 Activities from the South China Sea Sponge Aaptos aaptos     

Hao-Bing Yu  Fan Yang  Fan Sun  Jing Li  Wei-Hua Jiao  Jian-Hong Gan  Wen-Zhen Hu  Hou-Wen Lin 《Marine drugs》2014,12(12):6003-6013

Five new alkaloids of aaptamine family, compounds (1–5) and three known derivatives (6–8), have been isolated from the South China Sea sponge Aaptos aaptos. The structures of all compounds were unambiguously elucidated by spectroscopic analyses, as well as by comparison with the literature data. Compounds 1–2 are characterized with triazapyrene lactam skeleton, whereas compounds 4–5 share an imidazole-fused aaptamine moiety. These compounds were evaluated in antifungal and anti-HIV-1 assays. Compounds 3, 7, and 8 showed antifungal activity against six fungi, with MIC values in the range of 4 to 64 μg/mL. Compounds 7–8 exhibited anti-HIV-1 activity, with inhibitory rates of 88.0% and 72.3%, respectively, at a concentration of 10 μM.  相似文献   

Anti-Mycobacterial Nucleoside Antibiotics from a Marine-Derived Streptomyces sp. TPU1236A     

Ying-Yue Bu  Hiroyuki Yamazaki  Kazuyo Ukai  Michio Namikoshi 《Marine drugs》2014,12(12):6102-6112

Five new nucleoside antibiotics, named streptcytosines A–E (1–5), and six known compounds, de-amosaminyl-cytosamine (6), plicacetin (7), bamicetin (8), amicetin (9), collismycin B (10), and SF2738 C (11), were isolated from a culture broth of Streptomyces sp. TPU1236A collected in Okinawa, Japan. The structures of new compounds were elucidated on the basis of their spectroscopic data (HRFABMS, IR, UV, and 2D NMR experiments including ¹H-¹H COSY, HMQC, HMBC, and NOESY spectra). Streptcytosine A (1) belonged to the amicetin group antibiotics, and streptcytosines B–E (2–5) were derivatives of de-amosaminyl-cytosamine (6), 2,3,6-trideoxyglucopyranosyl cytosine. Compound 1 inhibited the growth of Mycobacterium smegmatis (MIC = 32 µg/mL), while compounds 2–5 were not active at 50 µg/disc. Bamicetin (8) and amicetin (9) showed the MICs of 16 and 8 µg/mL, respectively.  相似文献   

Anti-Inflammatory Activity and Mechanism of a Lipid Extract from Hard-Shelled Mussel (Mytilus Coruscus) on Chronic Arthritis in Rats     

Guipu Li  Yuanqing Fu  Jusheng Zheng  Duo Li 《Marine drugs》2014,12(2):568-588

The present study was designed to investigate the anti-inflammatory activity and mechanism of a lipid extract from hard-shelled mussel (Mytilus coruscus) on adjuvant-induced (AIA) and collagen-induced arthritis (CIA) in rats. AIA and CIA rats that received hard-shelled mussel lipid extract (HMLE group) at a dose of 100 mg/kg demonstrated significantly lower paw swelling and arthritic index, but higher body weight gain than those which received olive oil (control group). Similar results were found in arthritic rats that received New Zealand green-lipped mussel lipid extract (GMLE) at the same dosage. The levels of leukotriene B₄ (LTB₄), prostaglandin E₂ (PGE₂), thromboxane B₂ (TXB₂) in the serum, and interleukin-1β (IL-1β), IL-6, interferon-γ (INF-γ), tumor necrosis factor-α (TNF-α) in the ankle joint synovial fluids of HMLE group rats were significantly lower than those of control group. However, the levels of IL-4 and IL-10 in HMLE group rats were significantly higher than those in the control group. Decreased mRNA expressions of matrix metalloproteinase 1 (MMP1) and MMP13, but increased tissue inhibitor of metalloproteinase 1 (TIMP1) were observed in the knee joint synovium tissues of HMLE group rats when compared with the control group. No hepatotoxicity was observed in both HMLE and GMLE group rats. The present results indicated that HMLE had a similarly strong anti-inflammatory activity as GMLE. Such a strong efficacy could result from the suppression of inflammatory mediators (LTB₄, PGE₂, TXB₂), pro-inflammatory cytokines (IL-1β, IL-6, INF-γ, TNF-α) and MMPs (MMP1, MMP13), and the promotion of anti-inflammatory cytokines (IL-4, IL-10) and TIMPs (TIMP1) productions.  相似文献   

Antiplatelet and Anticoagulant Effects of Diterpenes Isolated from the Marine Alga,Dictyota menstrualis     

Laura de Andrade Moura  Ana Carolina Marqui de Almeida  Thaisa Francielle Souza Domingos  Fredy Ortiz-Ramirez  Diana Negr?o Cavalcanti  Valéria Laneuville Teixeira  André Lopes Fuly 《Marine drugs》2014,12(5):2471-2484

Cardiovascular diseases represent a major cause of disability and death worldwide. Therapeutics are available, but they often have unsatisfactory results and may produce side effects. Alternative treatments based on the use of natural products have been extensively investigated, because of their low toxicity and side effects. Marine organisms are prime candidates for such products, as they are sources of numerous and complex substances with ecological and pharmacological effects. In this work, we investigated, through in vitro experiments, the effects of three diterpenes (pachydictyol A, isopachydictyol A and dichotomanol) from the Brazilian marine alga, Dictyota menstrualis, on platelet aggregation and plasma coagulation. Results showed that dichotomanol inhibited ADP- or collagen-induced aggregation of platelet-rich plasma (PRP), but failed to inhibit washed platelets (WP). In contrast, pachydictyol A and isopachydictyol A failed to inhibit the aggregation of PRP, but inhibited WP aggregation induced by collagen or thrombin. These diterpenes also inhibited coagulation analyzed by the prothrombin time and activated partial thromboplastin time and on commercial fibrinogen. Moreover, diterpenes inhibited the catalytic activity of thrombin. Theoretical studies using the Osiris Property Explorer software showed that diterpenes have low theoretical toxicity profiles and a drug-score similar to commercial anticoagulant drugs. In conclusion, these diterpenes are promising candidates for use in anticoagulant therapy, and this study also highlights the biotechnological potential of oceans and the importance of bioprospecting to develop medicines.  相似文献   

Eunicellin-Based Diterpenoids,Hirsutalins N–R,from the Formosan Soft Coral Cladiella hirsuta     

Tzu-Zin Huang  Bo-Wei Chen  Chiung-Yao Huang  Tsong-Long Hwang  Chang-Feng Dai  Jyh-Horng Sheu 《Marine drugs》2014,12(5):2446-2457

New eunicellin-type hirsutalins N–R (1–5), along with two known eunicellins, (6 and 7) were isolated from the soft coral Cladiella hirsuta. The structures of the metabolites were determined by extensive spectroscopic analysis. Cytotoxic activity of compounds 1–7 against the proliferation of a limited panel of cancer cell lines was measured. The in vitro anti-inflammatory activity of compounds 1–7 was evaluated by measuring their ability in suppressing superoxide anion generation and elastase release in fMLP/CB-induced human neutrophils.  相似文献   

Quorum Quenching Agents: Resources for Antivirulence Therapy     

Kaihao Tang  Xiao-Hua Zhang 《Marine drugs》2014,12(6):3245-3282

The continuing emergence of antibiotic-resistant pathogens is a concern to human health and highlights the urgent need for the development of alternative therapeutic strategies. Quorum sensing (QS) regulates virulence in many bacterial pathogens, and thus, is a promising target for antivirulence therapy which may inhibit virulence instead of cell growth and division. This means that there is little selective pressure for the evolution of resistance. Many natural quorum quenching (QQ) agents have been identified. Moreover, it has been shown that many microorganisms are capable of producing small molecular QS inhibitors and/or macromolecular QQ enzymes, which could be regarded as a strategy for bacteria to gain benefits in competitive environments. More than 30 species of marine QQ bacteria have been identified thus far, but only a few of them have been intensively studied. Recent studies indicate that an enormous number of QQ microorganisms are undiscovered in the highly diverse marine environments, and these marine microorganism-derived QQ agents may be valuable resources for antivirulence therapy.  相似文献