The valve movement response of mussels: a tool in biological monitoring

Biological sensors are becoming more important to monitor the quality of the aquatic environment. In this paper the valve movement response of freshwater (Dreissena polymorpha) and marine (Mytilus edulis) mussels is presented as a tool in monitoring studies. Examples of various methods for data storage and data treatment are presented, elucidating easier operation and lower detection limits. Several applications are mentioned, including an early warning system based on this valve movement response of mussels.     

A novel, rapid method for the isolation of terminal sequences from yeast artificial chromosome (YAC) clones.

The recent development of yeast artificial chromosome (YAC) vectors has provided a system for cloning fragments that are over ten times larger than those that can be cloned in more established systems. We have developed a method for the rapid isolation of terminal sequences from YAC clones. The YAC clone is digested with a range of restriction enzymes, a common linker is ligated to the DNA fragments and terminal sequences are amplified using a vector specific primer and a linker specific primer. Sequence data derived from these terminal specific products can be used to design primers for a further round of screening to isolate overlapping clones. The method also provides a convenient method of generating Sequence Tagged Sites for the mapping of complex genomes.     

Lack of Change in Basal Ganglia Neuropeptide Content Following Subacute 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine Treatment of the Common Marmoset

Treatment of common marmosets with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP; 1-4 mg/kg for up to 4 days) caused a profound parkinsonian state. Ten days from the start of MPTP treatment, all animals showed marked motor impairment, consisting of bradykinesia and akinesia, limb rigidity, postural abnormalities, loss of vocalisation and blink reflex, and, on occasions, postural tremor. Measurement of caudate-putamen monoamine content at this time showed a profound loss in 3,4-dihydroxyphenylethylamine, homovanillic acid, and 3,4-dihydroxyphenylacetic acid concentrations. Measurement of neuropeptide concentrations in the caudate-putamen, internal and external segments of the globus pallidus, nucleus accumbens, substantia nigra, frontal cortex, and hippocampus showed met-enkephalin, leu-enkephalin, and cholecystokinin (CCK-8) concentrations to be unaffected by MPTP treatment. There was a small decrease in the substance P content of frontal cortex, but otherwise the content of this neuropeptide was unaltered. Parkinsonism in the marmoset, induced by MPTP treatment 10 days earlier, does not alter neuropeptide concentrations in the manner observed in Parkinson's disease.     

Specific [3H]Piflutixol Binding to CHAPS-Solubilised Rat Striatal Preparations Involves Dopamine D-2 but Not D-1 Binding Sites

[3H]Piflutixol binding to rat striatal membrane preparations identifies both D-1 and D-2 sites. We used [3H]piflutixol to characterise those binding sites present in 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS)-solubilised rat striatal preparations. The specific binding of [3H]piflutixol, as defined using cis-flupenthixol, to CHAPS-solubilised rat striatal tissue was saturable and of high affinity. Specific [3H]piflutixol binding to the solubilised preparations was displaced stereoselectively by the isomers of butaclamol and to an equal extent by both cis-flupenthixol and (+/-)-sulpiride. A positive correlation was found between the capacity of a range of drugs to displace [3H]piflutixol binding and the displacement of [3H]spiperone to the same preparations. The Bmax of [3H]piflutixol binding was not different from that of [3H]spiperone binding to the same preparation. These studies suggest that, in contrast to specific binding of membrane preparations, the specific binding of [3H]piflutixol to CHAPS-solubilised preparations involves mainly D-2 sites. Specific [3H]piflutixol binding, in contrast to [3H]spiperone binding, showed only slow dissociation from soluble preparations. The binding of [3H]piflutixol to CHAPS-solubilised preparations was retained during passage through a gel filtration column. This prelabelling of solubilised striatal preparations using [3H]piflutixol may aid in the purification of CHAPS-solubilised rat striatal D-2 sites.     

中国茶对变形链球菌的抑菌作用

对３６只ｓｐｒａｑｕｅ－Ｄａｗｌｅｙ鼠分４组给予诱龋饲料（Ｄｉｅｔ２０００,ｋｅｙｓ）,并连续５天在口腔内接种变链菌６７１５菌株,分别给予我国主要产茶区的三种茶浸液：龙井绿茶（Ｂ组）,四川涪陵红茶（Ｃ组）,乌龙茶（Ｄ组）,先用０．５ｇ茶和５０ｍｌ双蒸馏水加热煮沸过滤后浸泡１０分钟以及对照组（Ａ组）用双蒸馏水为饮料喂养实验鼠。实验６０天后,杀鼠观察计算鼠磨牙面的菌落形成单位（ＣＦＵ）和菌斑指数（ｐｌａｑｕｅｓｃｏｒｅ）均显著下降。实验结果,实验组和对照组菌斑指数下降值顺序如下：Ｃ组＞Ｄ组＞Ｂ组＞Ａ组,并与实验组含氟量有相关性。很多研究表明变链菌是较为肯定的致龋菌、茶中氟化物对变链菌生长、粘附都有抑制作用。本研究选用茶来源广泛、价廉、无毒安全等优点,为开拓新的防龋方法进行探索。     

Effects of temperature,salinity and agitation on byssus thread formation of zebra musselDreissena polymorpha

Byssus thread production ofD. polymorpha under different conditions of temperature, salinity and agitation were studied in the laboratory. The acclimation to salinity and temperature greatly affects the byssus production ofD. polymorpha. Byssus production of mussels was significantly reduced when temperature increased beyond 20°C and decreased below 10°C. Mussels with cut threads (for counting), produced a substantially increased number of threads. However, mussels with uncut byssus threads were comparatively more mobile. Byssus production of mussels did not vary significantly at salinities up to 3. Beyond this salinity byssus production was reduced significantly. Mussels increased their byssus production with increasing frequency of agitation.     

Increased striatal acetylcholine after 14 months cis-flupenthixol treatment in rats suggests functional supersensitivity of dopamine receptors

Rats received continuous administration of cis-flupenthixol (0.8-1.2 mg/kg/day) or trans-flupenthixol (0.9-1.2 mg/kg/day) in drinking water for 14 months. The administration of cis-flupenthixol, but not trans-flupenthixol, caused apparent cerebral dopamine receptor supersensitivity. Thus, animals receiving cis-flupenthixol, but not trans-flupenthixol, showed enhanced apo-morphine-induced stereotyped behaviour. Dopamine concentration in striatum was not altered by drug treatment but striatal HVA and DOPAC concentrations were reduced in animals receiving cis-flupenthixol, but not trans-flupenthixol. No consistent change in Bmax of KD for specific striatal 3H-spiperone binding was observed after 14 months drug intake. However, in cis-flupenthixol treated animals a 40% increase in Bmax was observed following 2 weeks drug withdrawal. Continuous cis-flupenthixol intake increased striatal acetylcholine concentrations; trans-flupenthixol was without effect. This suggests the apparent increase in cerebral dopamine receptor supersensitivity caused by continuous long-term cis-flupenthixol administration is of functional importance in the intact animal.     

A sensitive and specific radiometric method for the measurement of plasma histamine in normal individuals

A radioenzymatic method for assaying histamine using histamine-N-methyltransferase from guinea pig brain was modified to increase its sensitivity, precision, and specificity. This was achieved by incorporation of a thin-layer chromatography step and use of N_α-methyl histamine as an internal standard in each sample. No prior extraction of the plasma samples is required, permitting the assay of 30 samples in 1 working day. Histamine was detected in the plasma of 17 normal volunteers, at a level of 3.4 ± 0.69 nmol/liter (range 0.82 to 4.7 nmol/liter). In 19 asthmatics, a low-peak expiratory flow rate was found to be associated with a plasma histamine concentration above this “normal” range.