反相高效液相色谱-柱后衍生法分析检测鱿鱼中的生物胺

建立了水产品中多组分生物胺的反相高效液相色谱-柱后衍生-荧光检测方法。采用荧光试剂邻苯二甲醛（OPA）为柱后衍生化试剂,在Capcell Pak MG-C18色谱柱上,通过梯度洗脱使酪胺、腐胺、尸胺、组胺、胍丁胺、精胺和亚精胺等7种生物胺得到良好分离,在给定的浓度范围内,各组分生物胺呈现良好线性相关（R^2〉0.999）。在水产品中添加生物胺混合标准溶液,平均回收率为88.3%～110.1%,相对标准偏差RSD小于10%。结合水产品的感官鉴定、pH值和TVBN值测定等方法检测水产食品的新鲜程度,分析了鱿鱼在不同保藏温度、保藏时间下的生物胺种类及含量的变化。其中胍丁胺和尸胺在鱿鱼的保藏过程中发生最显著变化,可以作为其质量变化的参考指标。     

Flurazepam interaction with sodium and potassium channels in squid giant axon

External application of 0.05-1.0 mM flurazepam was found to partially block both sodium and potassium currents in voltage-clamped squid giant axons. At the same concentration the fractional block of the potassium current was found to be 3 times greater than that of the sodium current. In the presence of the drug the potassium current appeared to "inactivate', as flurazepam block became more profound during the course of the depolarization. The decay of the potassium current can be explained by a model in which flurazepam enters and blocks the potassium channels only after they have opened. Once bound in the potassium channel, removal of flurazepam from its binding site develops slowly (tau = 48 ms). Thus repetitive stimulation of the nerve produced a cumulative block. When applied inside the axon flurazepam was found to be 1.5 (n = 4) times more potent blocker of potassium channels than following external application. This result suggests that when applied externally, a neutral form of the drug diffuses across the membrane and blocks occurs from the inner end of the channel.     

鱿鱼皮胶原蛋白水解肽抗氧化活性研究

目的探讨秘鲁鱿鱼(Dosidicus eschrichitiiSteenstrup)皮胶原蛋白多肽组分对自由基的清除作用以及水解产物的体内抗氧化作用,为鱿鱼加工废弃物的高值化利用探索一条新途径。方法采用化学发光法研究胶原蛋白活性多肽体外对超氧阴离子自由基(O2.-)和羟自由基(.OH)的清除作用,并筛选出体外清除自由基活性最好的组分;灌胃于D-半乳糖致衰老的模型小鼠,测定小鼠血液及皮肤中的超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活力和丙二醛(MDA)及羟脯氨酸(Hyp)含量。结果与结论鱿鱼皮胶原蛋白多肽分子量小于2000D组分对O2.-和.OH具有较好的清除效果,该活性多肽组分可以提高小鼠血液及皮肤中SOD和GSH-Px的活力,降低MDA含量,并能提高小鼠皮肤组织中Hyp的含量。     

A case of retroperitoneal abscess caused by Salmonella Oranienburg

The authors report a case of retroperitoneal abscess caused by Salmonella Oranienburg in an 8-year-old girl. This was one case in an epidemic of food poisoning from Salmonella Oranienburg or Salmonella Chester transmitted by many kinds of contaminated dried squid products. This is the first reported case of a retroperitoneal abscess by Salmonella Oranienburg.     

Reconstitution of squid and cattle rhodopsin by the use of metaretinochrome in their respective membranes

Retinochrome is, even in membranes, converted to metaretinochrome by exposure to orange light. Upon incubation of metaretinochrome in membranes with cattle opsin in rod outer segment membranes, cattle rhodopsin is reconstituted in the dark. When opsin is present in molar excess to metaretinochrome, about 80% of the prosthetic retinal of retinochrome present initially is utilized for the reconstitution of cattle rhodopsin. One reason why all of the prosthetic retinal is not used for the rhodopsin reconstitution is that metaretinochrome transforms slowly to retinochrome during incubation in the dark and another is that metaretinochrome is in a photoequilibrium mixture with a trace of retinochrome after exposure to orange light.Squid rhodopsin is reconstituted when a mixture of metaretinochrome and squid opsin in their respective membranes is incubated in the dark. The reconstituted rhodopsin is converted to acid or alkaline metarhodopsin by exposure to orange light at neutral or alkaline pH, respectively.Three possible mechanisms for the transference of 11-cis retinal from metaretinochrome in a membrane to opsin in a different membrane were considered: (1) the migration of 11-cis retinal through an aqueous medium between the separate membranes, (2) the migration of 11-cis retinal from metaretinochrome to opsin in a fused membrane and (3) the transfer of retinal from membrane to membrane in close contact. In conclusion, the first two mechanisms were inapplicable and the third appeared to explain the present experimental findings.The possibility is discussed that the photoproduct of retinochrome may contribute to the rhodopsin synthesis as an effective donor of 11-cis retinal to opsin in the squid retina.     

人参根和茎叶皂苷对孤独饲养小鼠自发运动及攻击行为的影响

目的探讨乌贼墨提取物对氧化性损伤小鼠心、脑组织的保护作用以及在不同剂量条件下的作用效果。方法40只昆明系健康小鼠随机分为空白对照组、模型组、低、高剂量组。模型组腹腔注射环磷酰胺造氧化性损伤模型。检测各组小鼠心肌和脑组织中SOD(超氧化物歧化酶),MDA(丙二醛),CAT(过氧化氢酶),GSH-Px(谷胱甘肽过氧化物酶)变化,血液中SOD,MDA变化。结果环磷酰胺均能不同程度的影响上述指标的变化(P<0.01或P<0.05),说明造模成功。与模型组比较,不同剂量的乌贼墨提取物均能不同程度的抑制由环磷酰胺所致的上述指标的变化(P<0.01或P<0.05),但部分数据表明,较高浓度的提取物的抑制作用有所减弱,有的甚至不起作用。结论适当浓度的乌贼墨提取物对氧化性损伤小鼠心肌和脑组织具有一定的保护作用。     

Glutamate metabolism by squid nerve fiber sheaths

The extrasynaptic region of the squid giant nerve fiber exhibits neuron-Schwann cell interactions that appear to involve glutamate as a mediator. In an earlier work, it was demonstrated that the periaxonal sheaths of such nerves (where the Schwann cells are located) possess the capacity to transport glutamate. However there was no information available about the possible fate of the glutamate incorporated into the sheaths. In this study, it is demonstrated that the periaxonal sheaths of the extrasynaptic region of squid giant nerves are capable of metabolizing glutamate. Sheaths incubated with 10 μM [1-¹⁴C] glutamate produced [¹⁴C]O₂ in a manner proportional to time and estimated cell water volume. At least 45% of this CO₂ production was determined to be independent of transaminase catalyzed isotopic exchange, thus reflecting real degradation (decarboxylation) of glutamate. It was also demonstrated that the sheaths were capable of glutamine synthesis. Taken together, the findings of our laboratory indicate not only that the Schwann cells of the sheaths fulfil the requirements for a site for the uptake and metabolism of transmitter glutamate in the squid giant nerve but also that certain metabolic characteristics associated with the neuro-glial unit around synapses are also found in non-synaptic areas of nerve fibers. GLIA 23:298–303, 1998. © 1998 Wiley-Liss, Inc.     

Dependency of absorption characteristics of retinochrome on pH and salts

It has been suggested that, in the inner segments of the visual cells of cephalopods, retinochrome may be located in lamellated structures, often called myeloid bodies. When the outer segment-free retinas are homogenized and divided into light and heavy fractions by centrifuging in 43% sucrose, most of the myeloid bodies are concentrated into the light fraction, from which one can easily prepare fine extract of retinochrome. According to this improved method of preparation, the yield of retinochrome from the light fraction reaches more than 80% of the total contained in the inner segments.Within a pH range of about 5–7, the absorption maximum (λ_max) of retinochrome remains near 495 nm, irrespective of the pH of the medium. In the presence of salt, however, its λ_max moves with changes of pH, as shifted to 476 nm in 1 m-NaCl by lowering the pH from 6·2 to 4·8. The mere addition of a variety of 1 m-salt (NaCl, KCl, MgCl₂ and KBr) also causes the λ_max 495 nm at about pH 5·5 to shift 10–20 nm toward shorter wavelengths, maximally to 476 nm. In any case, these blue shifts can be reversed by raising the pH and an isosbestic point always appears near 477 nm.On irradiation with orange light, the acid extract of retinochrome is usually bleached exponentially in the absence of salt. With increasing salt concentration, the photobleaching becomes slow, and its overall process is more or less deviated from the first-order kinetics. When the sample finally has λ_max 476 nm, the bleaching again follows a first-order process, although its rate is greatly reduced.The present experiments shows that retinochrome at weakly acid pH exists in two tautomeric forms with their own λ_max at about 495 nm and 476 nm, depending on ionic conditions.