水母雪莲毛状根培养及黄酮类化合物生物合成的调控

水母雪莲(Saussurea medusa Maxim)为菊科凤毛菊属植物,是名贵中药材,其主要活性成分为黄酮类化合物。为解决雪莲资源匮乏，本文开展了利用水母雪莲毛状根培养生产黄酮类活性成分的研究。 在1/2MS液体培养基上研究了不同理化因子对水母雪莲毛状根生长和黄酮类化合物生物合成的影响。实验结果表明:氮源总浓度（包括NH4+和NO3-）为30 mmol/L;NH4+/NO3-比例为5:25;2 %蔗糖和3 %葡萄糖组合;0.5 mg/L GA3和0.5 mg/L IBA;pH 5.8;18 h/d���光照（光强为3500 Lux）;24℃;摇床转速为100 rpm的条件有利于毛状根生长及黄酮类化合物的生物合成。在此培养条件下，经过21 d���培养毛状根生长量达到12.8 g/L（DW），黄酮类化合物合成量为1922 mg/L，即黄酮类化合物含量占毛状根干重的15 %，约为野生水母雪莲植株干重黄酮类化合物含量的25倍。 用MJ和SA两种诱导子分别处理水母雪莲的毛状根，适宜条件下它们均能使毛状根中黄酮类化合物的产量得到提高。实验发现，在水母雪莲毛状根培养过程中，MJ抑制其生长，但提高了黄酮类化合物在毛状根中的百分含量;SA降低了黄酮类化合物在毛状根中的百分含量，但促进其生长。诱导子的作用效果与诱导子的浓度和添加时间有关。在延迟期后期添加浓度为0.02 mmol/L的MJ时黄酮类化合物产量达到 849 mg/L，比对照（633 mg/L）提高34.1 %;在指数生长期中期添加浓度为0.03 mmol/L的SA时，黄酮类化合物产量达到968 mg/L，比对照（633 mg/L）提高52.9 %。在指数生长期前期同时添加浓度为0.02 mmol/L的MJ 和0.03 mmol/L的SA，黄酮类化合物的产量为1125 mg/L，比对照（633 mg/L）提高77.7 %。 另外采取热水、碱提取，乙醇沉淀获得水母雪莲毛状根多糖。进一步用α-萘酚—浓硫酸法进行定性、定量分析，测得水母雪莲毛状根中水溶性多糖与碱溶性多糖的含量分别为2.453 %和3.391 % 。

A comparative study on the hatching of common carp eggs in hapa and hatchery (model CIFE D-80)

Common carp (Cyprinus carpio) eggs were incubated to study the efficiency of hatching in hapa and hatchery. During incubation the recorded temperature was 21-28 degree C and 20-31 degree C, dissolved oxygen 6-9 ppm. and 3-5 ppm., total alkalinity 180-250 ppm. and 28-62 ppm. respectively in the hatchery (model C.I.F.E. D-80) and hapa. CO sub(2) was totally absent in the hatchery, but recorded 3-10 ppm. in the hapa. The flow of water was maintained at 1.25 l/minute/jar in the hatchery. Under the above environmental conditions the eggs hatched in 42-51 hrs. in the hatchery and 61-81 hrs. in the hapa from egg to spawn thereby establishing the hatchery to be a better hatching system for carp eggs.

Antibacterial effect of the Indian squid, Loligo duvauceli (d'Orbigny), ink

The ink of the Indian squid Loligo duvauceli (d'Orbigny) was tested for antibacterial activity. The antibacterial effect of bacteria present in the ink gland was also tested. Only one type of bacteria was found to be present in the ink gland of squid and was identified as Photobacterium leiognathi. Among the various forms of ink extracts, the precipitated and freeze-dried ink showed more pronounced antibacterial effect against Gram-negative bacteria, Salmonella, spp. Escherichia coli, Vibrio cholerae, V. parahaemolyticus and Pseudoinonas spp., and a less pronounced effect against Gram-positive bacteria, Staphylococcus spp. and Micrococcus spp., P. leiognathi did not inhibit any of the above bacteria. The antibacterial activity was associated with the compounds of the ink.

Effects of physiological doses of vitamin D sub(3) (Cholecalciferol) on induced molting and growth in giant freshwater prawn, Macrobrachium rosenbergii (de Man)

Effects of three different doses of vitamin D sub(3) on molting, growth, and calcium and phosphate composition of tissue and molt during the grow-out of the giant freshwater prawn Macrobrachium rosenbergii (average weight 10.56 ± 0.20 g), obtained from a grow-out pond, were studied. Intramuscular doses of vitamin D sub(3) (100, 500 and 2000 IU/kg body weight) were given on the 1st, 3rd, 5th, 7th, 9th, 11th, 13th, 15th, 20th, 25th and 30th days. All the experimental animals were fed with a basal diet containing fish meal, shrimp meal, wheat flour, groundnut de-oiled cake, soybean meal and wheat bran at 3% of the body weight. The numbers of molts were recorded as 20±0.50, 29±1.16, 51±1.87, and 30±1.60 in control, 100, 500 and 2000 IU/kg body weight physiological doses, respectively. Maximum growth was recorded in prawns given 500 IU/ kg dose. Survival was between 58.33 ± 9.13 and 77.77 ± 8.61%. The ash content and calcium level increased significantly (p<0.05) and recorded the highest values in 500 IU/kg physiological dose. However, the inorganic phosphate (P sub(i)) content recorded the highest values in tissue in 2000 IU/kg dose (p<0.05, F = 50.60613). There is no significant difference in calcium contents (p>0.05) in both tissue and molt at 500 and 2000 IU/kg doses. It was found that a higher physiological dose (2000 IU/kg) of vitamin D sub(3) increased the rate of mortality. Results have shown that vitamin D sub(3) has a positive impact on the growth and survival of M. rosenbergii and it interferes with the metabolism of Ca and P sub(i), in tissue, and alters molting frequency. Results on physiological dose suggest an alternative and effective dietary supplementation method of vitamin D sub(3) in the grow-out phase of M. rosenbergii.

Investigation of the losses in the stator duct spacers of large A.C. motors using the A -ip 3-D eddy current formulation

This paper describes how the A -if) formulation may be applied to determine the losses in the stator duct spacers of large a.c. motors. The model is described in terms of its geometry and boundary conditions. The novel aspects of the application of the formulation to this problem are explained. These include the modelling of fixed currents sources (the stator windings), the location of the necessary cut surfaces and the determination of their magnetic scalar potential differences, and the implementation of periodic boundary conditions for vector variables. Results are presented showing how the duct spacer losses vary with load, and with the relative permeability of the spacer material. The effects of modelling iron nonlinearity, of both the spacer and the steel laminations, are also illustrated. © 1996 IEEE.

Economics of operation of 38' G.R.P. fishing vessels issued by the A.D.B. Fisheries Project: a case study

The author gives a financial and economic valuation of the operation of vessels in the 38 foot GRP class. He discusses particularly the materials and methods of fishing they use, species composition of their catches, their rate of return, break-even analysis, financial and social analysis.

Morphometry, length-weight relationship and biology of Sepia aculeata (d'Orbigny, 1848) from Mumbai coast, India

Seventeen morphometric characters of Sepia aculeata of Mumbai coast have been studied and the relationships of morphometric characters with dorsal mantle length (DML) were established. The characters compared showed a fair to high degree of correlation ('r' 0.63-0.99). Number of arm suckers and shell rings were related with DML. The shell rings also showed high degree of correlation with DML ('r' 0.79-0.95). However, the relationship between arm suckers and DML was not so good ('r' 0.1-0.4). The length-weight relationship is described as W=0.1821336 L sub(2.801102). Food and feeding analysis confirm the carnivorous feeding behaviour of the species. Mature females found in all months indicate that it has prolonged spawning season with two peaks, september and march-april. Absolute fecundity ranged from 214 to 4143 eggs.