大蹼铃蟾皮肤分泌物中βγ-CAT对血液和心血管系统作用及机制研究

非晶状体βγ-晶状体蛋白(non-lens βγ-crystallin, α-亚基)和三叶因子(trefoil factor, β-亚基) 复合物（non-lens βγ-crystallin and trefoil factor complex, 缩写为βγ-CAT）是从大蹼铃蟾皮肤中分离、纯化的一种新型蛋白, 具有促进细胞迁移、伤口愈合功能，同时还可通过核定位、调节转录因子和炎症相关蛋白诱导细胞脱落、凋亡。βγ-CAT对心血管和血液系统的作用和机制还不清楚。本研究的目的在于深入研究这些问题，为人类重大疾病的研究提供新思路。 首先，我们利用各种整体动物模型，研究了βγ-CAT对心血管系统和血液系统的影响。结果发现βγ-CAT可对白细胞、红细胞、血小板、肝细胞、肾细胞和心血管系统产生毒理作用。βγ-CAT可导致白细胞计数、红细胞计数和血小板计数减少、低血压、心律失常、心肌细胞轻度水肿、部分肺泡淤血、炎症细胞浸润肺泡壁、肝细胞水样变性、肾小管水肿、肾小球淤血和脾脏淤血、高钾血症、血糖升高、转氨酶和乳酸脱氢酶升高。我们推测βγ-CAT造成实验动物死亡的主要原因是心功能衰竭、高钾血症和白细胞毒素效应。 其次，为研究βγ-CAT对血管的效应，我们用兔胸主动脉进行了一系列的实验。结果表明，βγ-CAT可引起兔胸主动脉环剂量依赖性收缩，半数有效浓度为（EC50）10 nM; α-肾上腺素能受体阻断剂（酚妥拉明）和5-羟色胺受体阻断剂（S006）不能抑制βγ-CAT的血管收缩效应。因此，我们认为，整体实验观察到的低血压不是由于血管舒张造成的，而是由于βγ-CAT对心肌了产生了抑制效应，并且，βγ-CAT产生的血管收缩效应是通过新的途径引起的。 最后，我们把βγ-CAT导致兔死亡的原因归结为心血管系统衰竭，因为，一方面βγ-CAT抑制心肌使每搏量减少，另一方面它可收缩动脉使心脏的后负荷增加，从而导致重要器官、组织灌注不良而死亡。但导致心功能衰竭的机制还不清楚，于是，我们进行了离体心脏灌流、内皮细胞培养、细胞因子测定、免疫组化、凋亡实验，试图阐明导致动物心力衰竭的机制。首先，我们在离体心脏灌流装置上以恒压和恒流的灌流模式来研究βγ-CAT的心肌变力效应。接下来，我们用高钾去除冠脉血管内皮细胞，以评估内皮细胞在βγ-CAT对心肌的直接效应。最后，我们用βγ-CAT刺激培养的心内皮细胞和主动脉内皮细胞，之后检测细胞因子的释放；并用免疫组化的方法定位冠脉内皮和心肌细胞细胞因子的释放和对这些细胞的凋亡效应。实验一的结果表明，βγ-CAT导致心力衰竭的部分原因是由于βγ-CAT引起的冠脉血管收缩造成；实验二的结果表明，βγ-CAT引起的心力衰竭是内皮依赖的。实验三检测到心内皮、主动脉内皮和冠脉内皮释放TNF-α（TNF-α），高浓度的βγ-CAT还可诱导冠脉内皮凋亡，但不引起心肌细胞凋亡。综上所述，我们认为，冠脉内皮在βγ-CAT引起的心力衰竭中具有较大的贡献，通过冠脉内皮释放细胞因子（如TNF-α）作用于心肌细胞，从而导致收缩能力降低，引起心力衰竭。

A NOVEL ODOR SENSOR COATED WITH A LIPID-MEMBRANE

In this paper, an interdigital electrode lipid film odour sensor (ILOS) is designed, fabricated and tested. It is made from a microfabricated chemiresistor coated with a synthetic multibilayer film. Nine odorants in gas phase at room temperature have been detected using the odour sensor. For most of the odorants, the relation between the response of the ILOS and odorant concentration obeys Stevens' power law, and there is a good correlation between the minimum odorant concentrations that give rise to a change of the sensor's conductance and human olfactory thresholds.

Electro-mass multi odor sensor

For an olfactory sensor or electronic nose the task is not only to detect the object concentration, but also to recognize it. It is well known that all the elements can be identified by their charge to mass ratio e+/m. We tried to use this principle for molecular recognition. Two kinds of sensors are used simultaneously in testing. One is Quartz Crystal Microbalance (QCM) for detecting the change in mass, the other is Interdigital Electrode (IE) for detecting the change in conduction. In this paper the principle and the feasibility of this method are reported. The preliminary results on the recognition of alcohols are presented. The multisensor can be used as an instrument for research on material properties and kinetic process as well.

Concurrence of cat and tet genes in multiple antibiotic-resistant bacteria isolated from a sea cucumber and sea urchin mariculture farm in China

A basic understanding of abundance and diversity of antibiotic-resistant microbes and their genetic determinants is necessary for finding a way to prevent and control the spread of antibiotic resistance. For this purpose, chloramphenicol and multiple antibiotic-resistant bacteria were screened from a mariculture farm in northern China. Both sea cucumber and sea urchin rearing ponds were populated with abundant antibiotic-resistant bacteria, especially marine vibrios. Sixty-five percent chloramphenicol-resistant isolates from sea cucumber harbored a cat gene, either cat IV or cat II, whereas 35% sea urchin isolates harbored a cat gene, actually cat II. The predominant resistance determinant cat IV gene mainly occurred in isolates related to Vibrio tasmaniensis or Pseudoalteromonas atlantica, and the cat II gene mainly occurred in Vibrio splendidus-like isolates. All the cat-positive isolates also harbored one or two of the tet genes, tet(D), tet(B), or tet(A). As no chloramphenicol-related antibiotic was ever used, coselection of the cat genes by other antibiotics, especially oxytetracycline, might be the cause of the high incidence of cat genes in the mariculture farm studied.

Lateralized behaviour in the domestic cat, Felis silvestris catus

Lateralized behaviour in the felids has been subject to little investigation. We examined the paw use of 42 domestic cats on three tasks designed to determine whether the animals performed asymmetrical motor behaviour. The influence of the cats' sex and age on their paw preferences was also explored. The distribution of the cats' paw preferences differed significantly between the three tasks. Task 1, the most complex exercise involving retrieval of a food treat from an empty jar, encouraged the most apparent display of lateralized behaviour, with all but one animal showing a strong preference to use either their left or right paw consistently. Tasks 2 (an exercise involving reaching for a toy suspended overhead) and 3 (a challenge involving reaching for a toy moving along the ground) encouraged ambilateral motor performance. Lateralized behaviour was strongly sex related. Male and female cats showed paw preferences at the level of the population, but in opposite directions. Females had a greater preference for using their right paw; males were more inclined to adopt their left paw. Feline age was unrelated to either strength or direction of preferred paw use. Overall, the findings suggest that there are two distinct populations of paw preference in the cat that cluster strongly around the animals' sex. The results also point to a relationship between lateralized behaviour and task complexity. More apparent patterns of lateralized behaviour were evident on more complex manipulatory tasks, hinting at functional brain specialization in this species. © 2009 The Association for the Study of Animal Behaviour.

The ontogenesis of lateralized behavior in the domestic cat, Felis silvestris catus

For the first time, the development of paw preferences in the domestic cat, Felis silvestris catus, is explored. Twelve cats were tested at ages 12 weeks, 6 months, and 1 year on a challenge requiring them to use one of their paws to retrieve food. To control for repeated testing of the same cats at different ages, the subjects' paw preferences were compared with those of cats tested just once, at 6 months (n = 11) or 1 year (n = 14) of age. Analysis revealed a significant effect of age on the distribution of cats' paw preferences. Cats were significantly more likely to be ambilateral than paw preferent at 12 weeks and at 6 months but more likely to display a lateral bias in paw use at 1 year. There was a significant positive correlation between cats' paw preferences at 6 months and at 1 year. Lateralized behavior was strongly sex related. Females had a greater preference for using their right paw; males were significantly more inclined to adopt their left. Analysis revealed no significant difference in the direction or strength of paw preferences of cats tested longitudinally or cross-sectionally at 6 months or 1 year of age. Findings indicate that cats develop paw preferences by 1 year and hint at a relative stability in preferred paw use over time. The strong sex effect observed strengthens the case for the influence of a biological mechanism in the emergence of motor asymmetry in cats.