Similar carbohydrate but enhanced lactate utilization during exercise after 9 wk of acclimatization to 5,620 m

We hypothesized that reliance on lactate as a means of energy distribution is higher after a prolonged period of acclimatization (9 wk) than it is at sea level due to a higher lactate Ra and disposal from active skeletal muscle. To evaluate this hypothesis, six Danish lowlanders (25 +/- 2 yr) were studied at rest and during 20 min of bicycle exercise at 146 W at sea level (SL) and after 9 wk of acclimatization to 5,260 m (Alt). Whole body glucose Ra was similar at SL and Alt at rest and during exercise. Lactate Ra was also similar for the two conditions at rest; however, during exercise, lactate Ra was substantially lower at SL (65 micro mol. min(-1). kg body wt(-1)) than it was at Alt (150 micro mol. min(-1). kg body wt(-1)) at the same exercise intensity. During exercise, net lactate release was approximately 6-fold at Alt compared with SL, and related to this, tracer-calculated leg lactate uptake and release were both 3- or 4-fold higher at Alt compared with SL. The contribution of the two legs to glucose disposal was similar at SL and Alt; however, the contribution of the two legs to lactate Ra was significantly lower at rest and during exercise at SL (27 and 81%) than it was at Alt (45 and 123%). In conclusion, at rest and during exercise at the same absolute workload, CHO and blood glucose utilization were similar at SL and at Alt. Leg net lactate release was severalfold higher, and the contribution of leg lactate release to whole body lactate Ra was higher at Alt compared with SL. During exercise, the relative contribution of lactate oxidation to whole body CHO oxidation was substantially higher at Alt compared with SL as a result of increased uptake and subsequent oxidation of lactate by the active skeletal muscles.     

The effect of temperature on energy distribution during the last-larval stadium of the female house cricket, Acheta domesticus

The distribution of energy during the last stadium of the house cricket at two temperatures was the main theme of this study. Food consumption, growth, and oxygen consumption were greater in the first half of the stadium at both 25 and 35°C. An RQ > 1 indicated the conversion of carbohydrates to lipids during the first half of the instar at both temperatures. The duration of the stadium increased from 6 days at 35°C to 14 days at 25°C. The same maximal weight, protein content and lipid content were attained at both 25 and 35°C. A weight loss (mostly in stored lipids) after the midstadium peak weight was greater at the lower temperature. The absorption efficiency and the production of metabolic wastes were not affected by temperature, but the metabolic efficiency was much higher at 35 than at 25°C during the first half as well as the latter half of the stadium. Although during the first half of the stadium more energy was ingested, absorbed, and made available for growth at 25 than at 35°C, only slightly more growth occurred at 25°C. During the last half of the stadium less energy was ingested at 25 than at 35°C, and much more growth occurred at 35°C because of the even greater heat loss at 25 than at 35°C. Therefore at a lower temperature cricket larvae eat slightly more and reach the same maximal weight as at a higher temperature, but they end up smaller because they waste more energy during the extended duration of the stadium at the lower temperature.     

Biotransformation of ent-13-epi-manoyl oxides difunctionalized at C-3 and C-12 by filamentous fungi

Biotransformation of ent-3beta,12alpha-dihydroxy-13-epi-manoyl oxide with Fusarium moniliforme gave the regioselective oxidation of the hydroxyl group at C-3 and the ent-7beta-hydroxylation. The action of Gliocladium roseum in the 3,12-diketoderivative originated monohydroxylations at C-1 and C-7, both by the ent-beta face, while Rhizopus nigricans produced hydroxylation at C-7 or C-18, epoxidation of the double bond, reduction of the keto group at C-3, and combined actions as biohydroxylation at C-2/epoxidation of the double bond and hydroxylation at C-7/reduction of the keto group at C-3. In the ent-3-hydroxy-12-keto epimers, G. roseum originated monohydroxylations at C-1 and C-7 and R. nigricans originated the oxidation at C-3 as a major transformation, epoxidation of double bond and hydroxylation at C-2. Finally, in the ent-3beta-hydroxy epimer R. nigricans also originated minor hydroxylations at C-1, C-6, C-7 and C-20 and F. moniliforme produced an hydroxylation at C-7 and a dihydroxylation at C-7/C-11.     

Productivity of Thai Brahman and Simmental-Brahman crossbred (Kabinburi) cattle in central Thailand

The productivity of the new crossbred cattle Kabinburi (K) was compared to that of Thai Brahman (TB) using 756 production records from K cattle and 1,316 production records from TB cattle kept at three locations in Thailand. The data were analyzed for the effect of breeds and locations. The ambient temperature, the humidity, the Temperature–Humidity Index (THI) and the rainfall of the three locations were different. Lamphayaklang Livestock Research and Breeding Center (LP) had the highest rainfall/year followed by Nongkwang Livestock Research and Breeding Center (NK), and Prachinburi Livestock Breeding Station (PC). Kabinburi cattle had a higher bodyweight at birth as well as at 200, 400 and 600 days of age than TB cattle. Furthermore, K heifers gave birth to their first calf at a younger age and had a shorter calving interval than TB cows. Thai Brahman cattle kept at LP had significantly higher bodyweight at 400 and 600 days than the animals kept at NK, but bodyweight at birth and 600 days of age were not significantly different. Thai Brahman cattle kept at LP were younger at first calving and had a shorter calving interval than the animals kept at NK. K cattle kept at NK were heavier at birth and at 200, 400 and 600 days of age than the animals kept at PC. Furthermore, Kabinburi cows kept at NK were younger at first calving (P < 0.01), but the calving interval was not different between the two groups kept at NK or PC.     

四种农药对小菜蛾体温的影响

【目的】本研究旨在为阐明小菜蛾Plutellaxylostella体温在其防治中的应用价值提供资料。【方法】在不同人工气候箱内温度(环境温度)下,测定小菜蛾2, 3和4龄幼虫的体温,建立各龄幼虫体温(y)与环境温度(x)的关系方程;同时测定了不同环境温度下不同浓度阿维菌素、毒死蜱、氟虫腈和高效氯氰菊酯分别处理后小菜蛾3龄幼虫在不同处理时间的体温。【结果】小菜蛾2, 3和 4龄幼虫体温(y)与环境温度(x)关系方程分别为y＝0.95x+1.19(r=0.9463), y＝0.95x+1.18(r=0.9988),以及y＝0.93x+1.45(r=0.9989),等温点分别为22.16℃,21.40℃和21.41℃。在气候箱温度设定为15℃或40℃时,4种农药都对小菜蛾3龄幼虫体温无影响;而其他温度条件下,农药处理都可能改变小菜蛾3龄幼虫体温。对于阿维菌素,25℃下 2, 4和8 mg/L处理12 h,2和4 mg/L处理24 h, 0.5, 2, 4和8 mg/L处理36 h以及0.5, 1, 2和8 mg/L处理48 h时3龄幼虫体温均显著高于对照, 8 mg/L阿维菌素处理24 h时3龄幼虫体温显著低于对照;30℃下0.5 mg/L处理24 h及1 mg/L处理36 h 3龄幼虫体温显著低于对照,1 mg/L处理48 h和各浓度处理60 h时3龄幼虫体温均显著高于对照;35℃下只有1和8 mg/L处理48 h时3龄幼虫体温显著低于对照。对于毒死蜱,20℃下50, 200和800 mg/L处理24 h, 100, 400和800 mg/L处理36 h时3龄幼虫体温都显著低于对照;25℃下100和200 mg/L处理12h, 800 mg/L处理24 h, 100, 200和800 mg/L处理60 h时3龄幼虫体温均显著低于对照,而50, 100, 200和400 mg/L处理24 h, 100和200 mg/L处理36 h及100和400 mg/L处理48 h时3龄幼虫体温均显著高于对照;30℃下只有800 mg/L处理24 h时3龄幼虫体温显著低于对照,50, 100, 200和800 mg/L处理60 h时3龄幼虫体温显著高于对照。对于氟虫腈,20℃下只有0.5 mg/L处理36 h时3龄幼虫体温显著低于对照;25℃下 4 mg/L处理12 h和各浓度处理60 h时3龄幼虫体温显著低于对照,0.5 mg/L处理24 h以及0.25, 1和2mg/L处理48 h时3龄幼虫体温均显著高于对照;30℃下 0.25和0.5 mg/L处理12 h, 0.25和2 mg/L处理24h, 4 mg/L处理48 h以及2 mg/L处理60 h时3龄幼虫体温显著低于对照;35℃下只有0.25和0.5 mg/L处理60 h时3龄幼虫体温显著高于对照。对于高效氯氰菊酯,20℃下2和8 g/L处理36 h, 4和8 g/L处理48 h时3龄幼虫体温显著高于对照;25℃下 2, 4和8 g/L处理12 h时3龄幼虫体温均显著低于对照, 0.5, 4和8g/L处理24 h, 1, 4和 8 g/L处理36 h以及1, 2和4 g/L处理60 h时3龄幼虫体温均显著高于对照;30℃下 0.5和1 g/L浓度处理12 h, 0.5, 1, 4和8 g/L处理24 h以及1, 2和8 g/L处理60 h时3龄幼虫体温都显著低于对照。【结论】小菜蛾幼虫自律性体温调节能力低;阿维菌素、毒死蜱、氟虫腈或高效氯氰菊酯处理影响小菜蛾3龄幼虫的体温,影响形式随农药种类和浓度,环境温度及处理时间不同而不同。本研究拓宽了农药毒理学及害虫防治研究内容。     

Thermoinactivation of human cytomegalovirus

Vonka, Vladimir (Baylor University College of Medicine, Houston, Tex.), and Matilda Benyesh-Melnick. Thermoinactivation of human cytomegalovirus. J. Bacteriol. 91:221-226. 1966.-The inactivation at 4 and 37 C of several strains of human cytomegalovirus was studied. The preliminary findings that freshly harvested cytomegalovirus was inactivated more rapidly at 4 C than at higher temperatures was confirmed. Intracellular virus still within infected cells was found to be more stable at 4 C than virus released by sonic treatment just before incubation at 4 C. The composition of the diluent played an important role. In tris(hydroxymethyl)-aminomethane buffer, virus was unstable at both 4 and 37 C, with the rate of inactivation faster at 4 than at 37 C. Similar results were obtained when bicarbonate-phosphate buffer or Eagle's medium when bicarbonate was used as virus diluent. Calf serum stabilized the virus at 37 C, but not at 4 C. The deletion of bicarbonate from Eagle's medium had a stabilizing effect at both temperatures. An even greater stabilizing effect at both 4 and 37 C was obtained when distilled water was used as virus diluent. Inactivation rates varied from one strain to the next at 4 C but not at 37 C. Differences were found also with virus progeny derived from a single strain, but harvested at different stages during virus multiplication. Virus harvested early was more labile at 4 than at 37 C, whereas the late virus was more labile at the higher temperature. Intracellular and extracellular virus preparations were inactivated at the same rates at either 4 or 37 C.     

Compartmentation of the inulin space in mouse brain slices

(1) Mouse cerebrum slices swell in tris-buffered Krebs-Ringer medium. Swelling is rapid at first, then slows to a more or less constant rate. Even after 3 hr incubation, water content/g of tissue dry wt. shows no sign of an asymptotic limit. Swelling is the same at 37 degrees and at 0 degree. (2) Tissue water measured by incubation with tritiated water is equal to total tissue water measured by drying slices. Equilibration between tritiated water and tissue water is complete within 2 min. (3) Tissue liquid can be divided into three phenomenologically distinguishable compartments: first inulin space, which is the compartment permeable to inulin at both 0 degree and 37 degrees; second inulin space, which is the compartment permeable to inulin at 37 degrees but not at 0 degree; and 37 degrees non-inulin space, which is the compartment impermeable to inulin at both 0 degree and 37 degrees. The evidence for this is: (a) Penetration of inulin into tissue is greater at 37 degrees than at 0 degree. After the first 20 min the rate of penetration at 0 degree is approximately equal to the rate of penetration at 37 degrees, and only slightly less than the rate of increase of total tissue water. Therefore the smaller inulin space observed at 0 degree cannot be due to slower entry of inulin. (b) The inulin content of slices incubated in inulin-containing medium at 37 degrees and cooled to 0 degree in the same medium is the same as the inulin content of tissue incubated at 37 degrees without subsequent cooling. In contrast, the inulin content of tissues preincubated in inulin-free medium at 37 degrees and then incubated in inulin-containing medium at 0 degree is the same as the inulin content of tissues incubated in inulin-containing medium at 0 degree without preincubation at 37 degrees. Therefore the smaller inulin space at 0 degree than at 37 degrees can be due neither to a reversible temperature-dependent change in the size of one single inulin space nor to an irreversible, greater swelling of a single inulin space at the higher temperature, but is due to some portion of the 37 degrees inulin space becoming impermeable to inulin at 0 degree. (c) Some inulin is retained by tissue incubated with inulin at 37 degrees, then transferred to inulin-free medium at 0 degree; the amount of retained inulin is equal to the difference between inulin content of tissue incubated with inulin at 37 degrees and tissue incubated with inulin at 0 degree This confirms 3b above and in addition shows that inulin which has entered the second inulin space at 37 degrees is trapped there when this space becomes impermeable to inulin at 0 degree. (4) The penetration of the amino acids, L-lysine and D-glutamate at 0 degree is equal to the penetration of inulin at 37 degrees. This confirms the real existence of the 37 degrees inulin space at 0 degree, and shows that the barrier at 0 degree between the first and second inulin spaces does not exist for these substances. (5) The amino acids L-leucine and glycine penetrate total tissue water at 0 degree. L-leucine is actively transported at this temperature. (6) The amino acids alpha-aminoisobutyric acid, L-leucine, and L-lysine at 2 mM have no effect at 37 degrees on either the inulin space or the non-inulin space. (7) The inulin space is insensitive at 37 degrees to physiologically significant changes in the medium. In contrast, the non-inulin space is quite sensitive to these changes. Addition of D-glutamate greatly increases the non-inulin space; addition of ouabain or cyanide, or omission of glucose, increases the non-inulin space slightly; and replacement of Na+ ion by choline+ ion greatly decreases this space. These changes are independent and roughly additive.     

含水量与温度对球孢白僵菌孢子粉贮存寿命的影响及模拟分析

将含水量 1 12 %、4 73%、7 2 3%、9 84 %及 14 11%的球孢白僵菌BeauveriabassianaSG870 2分生孢子粉在4℃和 2 5℃下黑暗贮存 18个月 ,定期检测活孢率 ,以确定孢子粉的贮存寿命。结果显示 ,各温度处理中含水量显著(P <0 0 5 )影响孢子贮存期间的活孢率。在 4℃下 ,含水量为 1 12 %～ 9 84 %处理的活孢率在头 16个月均稳定在91%以上 ,且相互间差异不显著 ;次高含水量处理的活孢率在第 18个月才显著低于其它较低含水量处理 ;高含水量处理的活孢率则从第 6个月起显著低于其余较低含水量处理 ,第 12个月时降至 2 4 2 %。而在 2 5℃下 ,第 3和第 6个月的活孢率在不同含水量处理间均呈极显著差异 (P <0 0 1) ,即随含水量升高而显著下降 ,次高含水量处理在第6个月的活孢率仅剩 17 6 %。贮存期间活孢率对贮存时间和孢子粉含水量的依赖关系很符合改进的存活衰变模型(r2 >0 85 )。根据拟合的模型预测 ,在 4℃下贮存 ,若保证活孢率 90 % ,12 %含水量的孢子粉可贮存 7 3个月 ,10 %为 11 2个月 ,9%为 14 9个月 ,8%为 2 1 0个月 ,7%为 33 0个月 ,6 %达 6 5 5个月 ,故孢子粉冷贮的含水量应控制在8%以下。若在 2 5℃下贮存并保证活孢率 80 % ,含水量 10 %的孢子粉仅可贮存 1 7个月 ,8%为 2 3个月 ,6 %为 3 0个     

粘虫的胚胎发育

粘虫(Mythimna separata)胚胎发育经过卵裂及胚盘形成、胚带及原肠发生、胚带分节及附肢形成、体壁形成及背向闭合、胚胎反转和器官发生与形成6个时期。粘虫卵在25℃,胚胎发育至12h,胚带呈新月形或“C”字形。随着原肠发生,首先出现口陷与肛陷,与此同时,胚带逐渐伸长并开始分节。胚胎发育至32h,胚带头尾相接并呈波浪形弯曲,在胚胎反转前,胚胎发育至42h,前肠、后肠及马氏管已经形成。胚胎发育至54h时,胚动完成之 后,中肠才明显可见。同时将大量卵黄包围起来。神经系统的发生与气管形成始于原肠发生之后,至胚胎反转之前,神经节索才出现,随着胚动发生,神经节体积不断增大,腹神经索逐渐形成,纵走气管明显可见。     

Sea growth, smolt age and age at sexual maturation in Atlantic salmon

Relationships between growth at sea, smolt size and age at sexual maturation of Atlantic salmon Salmo salar were tested. The fish were offspring of brood stocks sampled in eight Norwegian rivers at latitudes between 59° and 70° N, hatchery reared and released at smolting at the mouth of the River Imsa (59° N). Smolt size influenced the subsequent growth rate of Atlantic salmon. The larger the fish were at release, the slower the yearly length increment at sea. Mean sea age at sexual maturity, measured as proportion of the returning adults attaining sexual maturity at sea age 2 years, was significantly correlated with mean growth rate during the first year at sea and mean smolt size ( r ²= 0·74, P < 0·001). Fish attaining maturity at a relatively high sea age were more fast growing during their first year at sea than those maturing at a younger age. The results indicate that high sea age at sexual maturation is a population-specific characteristic and associated with high early growth rate at sea.     

Effect of Temperature on Growth, Development and Reproduction of Meloidogyne hapla in Lettuce

Temperature was an important factor in growth, development and reproduction of Meloidogyne hapla in lettuce. Growth, as measured by increase in diameter of females, was not appreciably different at the intermediate (21.1 C night and 26.7 C day) and high (26.7 C night and 32.2 C day) temperature regimes, but was considerably less at the low temperature regime (15.5 C night and 21.1 C day) than at the two higher temperature regimes. Second-stage female larvae developed into adults 14 days after inoculation at the high, 18 days at the intermediate and 34 days at the low temperature regime. Eggs were observed 20 days after inoculation at the high, 26 days at the intermediate and 54 days at the low temperature regime. Number of eggs and larvae after 6 weeks was greater at the high than at the intermediate temperature regime and no eggs or larvae occurred at the low temperature regime during the observed 6 weeks.     

Inactivation of single cardiac Na+ channels in three different gating modes.

In small cell-attached patches containing one and only one Na+ channel, inactivation was studied in three different gating modes, namely, the fast-inactivating F mode and the more slowly inactivating S mode and P mode with similar inactivation kinetics. In each of these modes, ensemble-averaged currents could be fitted with a Hodgkin-Huxley-type model with a single exponential for inactivation (tauh). tauh declined from 1.0 ms at -60 mV to 0.1 ms at 0 mV in the F mode, from 4.6 ms at -40 mV to 1.1 ms at 0 mV in the S mode, and from 4.5 ms at -40 mV to 0.8 ms at +20 mV in the P mode, respectively. The probability of non-empty traces (net), the mean number of openings per non-empty trace (op/tr), and the mean open probability per trace (popen) were evaluated at 4-ms test pulses. net inclined from 30% at -60 mV to 63% at 0 mV in the F mode, from 4% at -90 mV to 90% at 0 mV in the S mode, and from 2% at -60 mV to 79% at +20 mV in the P mode. op/tr declined from 1.4 at -60 mV to 1.1 at 0 mV in the F mode, from 4.0 at -60 mV to 1.2 at 0 mV in the S mode, and from 2.9 at -40 mV to 1.6 at +20 mV in the P mode. popen was bell-shaped with a maximum of 5% at -30 mV in the F mode, 48% at -50 mV in the S mode, and 16% at 0 mV in the P mode. It is concluded that 1) a switch between F and S modes may reflect a functional change of inactivation, 2) a switch between S and P modes may reflect a functional change of activation, 3) tauh is mainly determined by the latency until the first channel opening in the F mode and by the number of reopenings in the S and P modes, 4) at least in the S and P modes, inactivation is independent of pore opening, and 5) in the S mode, mainly open channels inactivate, and in the P mode, mainly closed channels inactivate.     

Monitoring of chemical fertilizers on toxicity of two carbamate insecticides to the cyanobacterium Anabaena PCC 7120

The effects of individual chemical fertilizers (urea, superphosphate and potash) on the toxicity of two carbamate insecticides (carbaryl and carbofuran) to the nitrogen-fixing cyanobacterium Anabaena PCC 7120, were studied in vitro at partial lethal levels of each insecticide. Urea at 10 and 50 ppm levels reduced the toxicity due to carbaryl at 50 ppm partial lethal dose and due to carbofuran at 100 and 250 ppm partial lethal doses. Urea at 100 ppm enchanced the toxicity of both insecticides. Superphosphate at 10 ppm reduced the toxicity of carbaryl at 50 ppm and carbofuran at 100 and 250 ppm, but it enhanced the toxicity due to both insecticides at 50 ppm superphosphate. The toxicity due to carbaryl at 40 and 60 ppm were reduced by 100 and 200 ppm potash, but higher potash levels caused enhancement of toxicity. Carbofuran toxicity at 100 ppm was reduced but at 250 ppm the toxicity was enhanced with 100 ppm potash. Urea, superphosphate and potash caused no significant change in number of vegetative cells between the successive heterocysts at 10 and 50 ppm of urea and superphosphate, respectively, and 100 ppm of potash.     

Cytochromes of aquatic fungi

The cytochrome systems of two classes of aquatic fungi, the Oomycetes and Chytridiomycetes, were studied by means of reduced-minus-oxidized difference spectra at room and at low temperature. At room temperature, all of these fungi have a c-type cytochrome with an absorption maximum at 551 mmu and a b-type cytochrome at 564 mmu. The Oomycetes have a-type cytochromes at 605 mmu, and the Chytridiomycetes have a-type cytochromes at 606 mmu (Blastocladiales) or at 609 mmu (Monoblepharidales). Additional b-type cytochromes are found at 557 mmu in the Oomycetes and at approximately 560 mmu in the Chytridiomycetes. The data obtained from spectra at low temperature are consistent with these conclusions. Thus, the difference spectra reveal variation between the cytochrome systems of these two classes of aquatic fungi.     

Diurnal rhythms of pinealocyte ultrastructure, pineal serotonin content and plasma melatonin level in the domestic pig

The study was conducted to investigate diurnal changes in pinealocyte ultrastructure, pineal serotonin content and plasma melatonin concentration in the domestic pig. The immature pigs (n=24) were kept under a cycle of 12 h light : 12 h dark, with a photophase between 0800 and 2000. During the photophase the animals were exposed to direct sunlight. After four weeks the gilts were slaughtered at 0900, 1400, 2100 and 0200. The pineals were removed and divided into two parts - one for quantitative ultrastructural study (by a point count method) and one for serotonin assay. Simultaneously, blood samples were taken for melatonin assay. The relative volume of mitochondria in pinealocyte perikarya was significantly higher at 1400 than at 0200 and 0900 as well as at 2100 than at 0200. The relative volume of Golgi apparatus was higher at 0900 and 1400 than at 0200. The relative volume of dense bodies of the MBB-1 type in pinealocyte perikarya was significantly lower at 1400 and 2100 than at 0900. In contrast, the relative volume of MBB-2 was higher at 1400 than at 0900 and 0200. The numerical density of DCV in perikarya was significantly higher at 0200 than at 1400. No significant differences were found in rough endoplasmic reticulum, lysosomes and multivesicular bodies. The pineal serotonin content showed a prominent rhythm with the maximum at 1400. The plasma melatonin concentration was significantly higher at 0200 than at 0900, 1400 and 2100. The obtained results demonstrate that both pinealocyte ultrastructure and pineal biochemistry in the pig undergo significant changes in the course of the diurnal rhythm.     

Some catalytic and molecular properties of threonine deaminase from Bacillus stearothermophilus.

Threonine deaminase [EC 4.2.1.16] was highly purified from Bacillus stearothermophilus. The enzyme exhibited maximum activity at 65 degrees and at pH 9.2--9.6. It was inactivated on dilution and on storage at 4 degrees, but was protected by egg albumin. The enzyme was labile at 65 degrees, but became stable in the presence of egg albumin and isoleucine at pH 7.0. The substrate saturation curve for the enzyme reaction at 40 or 65 degrees was hyperbolic, but in the presence of isoleucine, the curve became sigmoidal (n = 2). The enzyme was more sensitive to isoleucine at 40 degrees than at 65 degrees, while valine slightly inhibited the enzyme at both 40 and 65 degrees. Inhibition of the enzyme by isoleucine was antagonized by valine at 40 and 65 degrees. These properties were essentially similar to those of the enzymes from mesophilic and thermophilic bacteria. The enzyme existed in two forms with different molecular sizes, 1.5-5 X 10(6) and 2 X 10(5) daltons, at pH 7.0 and at temperatures below 40 degrees. The larger component disaggregated into the small one at pH 8.5 or above, at temperatures above 50 degrees or in the presence of isoleucine and valine.     

Early development of fin-supports ani fin-rays in the milkfishChanos chanos

Development of fin-supports and fin-rays was observed in larval and juvenileChanos chanos, Chondrification of the caudal complex started at 4.70 mm SL. Ossification of the caudal elements started at 7.80 mm SL and was nearly completed at about 30 mm SL. Cartilaginous fusion of caudal elements, which occurs in hypurals of higher teleostean fishes but is not seen in lower teleosts, was observed between the neural arch of the preural centrum 1 and that of the ural centrum 1 via a small cartilage bridging the distal tips of the two arches. Caudal finrays began to develop at 6.60 mm SL, and an adult complement of principal rays was attained at 7.35 mm SL. Dorsal and anal pterygiophore elements were first evident at 6.70 mm and 6.65 mm SL, respectively. All proximal radiais were formed at 8.15 mm SL in both fins. Formation of dorsal and anal fin-rays started simultaneously at 8.60 mm SL, and adult fin-ray complements were attained at 10,00 mm and 10.70 mm SL, respectively. In the pectoral fin, the cleithrum, coraco-scapular cartilage and blade-like cartilage (fin plate) had already been formed at 4.65 mm SL. The mesocoracoid was observed to originate from the coraco-scapular cartilage and become detached from it in the course of ossification. Pectoral fin-ray formation started at 13.80 mm SL and was completed in number of rays at 20.00 mm SL. In the pelvic fin, the basipterygium was first evident at 13.00 mm SL. Pelvic fin-rays appeared at 13.80 mm SL and attained their adult count at 17.15 mm SL.     

Effects of low culture temperature on the induction of hsp70 mRNA and the accumulation of hsp70 and hsp105 in mouse FM3A cells.

We have shown that heat shock does not induce the synthesis of hsp70 in FM3A cells maintained at a low culture temperature of 33 degrees C although it does so in cells maintained at 37 degrees C [T. Hatayama et al. (1991) Biochem. Int. 24, 467-474]. In this paper, we show that FM3A cells maintained at 37 degrees C produced hsp70 mRNA during continuous heating at 42 degrees C or during postincubation at either 37 or 33 degrees C after being heated at 45 degrees C for 15 min, whereas cells maintained at 33 degrees C did not produce hsp70 mRNA during continuous heating at 37, 39, 42, or 45 degrees C, or during postincubation after being heated at any temperature. Thus the lack of hsp70 synthesis in cells maintained at 33 degrees C seemed to be due to the absence of hsp70 mRNA induction. Also, hsp70 was accumulated in cells maintained at 37 degrees C during continuous heating at 42 degrees C and during postincubation at 37 degrees C after heat shock at 45 degrees C, but not during postincubation at 33 degrees C. The cellular level of the constitutive hsp73 as well as the mRNA level were both similar in cells maintained at 33 and 37 degrees C. On the other hand, the cellular level of the constitutive hsp105 in cells maintained at 33 degrees C was only half of that in cells maintained at 37 degrees C. These hsp105 levels increased significantly in both types of cells after continuous heating at 39 degrees C. These findings indicate that the culture temperature affects not only the induction of hsp70 mRNA but also the accumulation of hsp70 and hsp105 in the cells.     

Characterization and evaluation of Aspergillus oryzae lactase coupled to a regenerable support

A derivative of crosslinked Sepharose, p-(N-acetyl-L-tyrosine azo) benzamidoethyl-CL-Sepharose 4B, was synthesized and used for the selective immobilization of thermostable lactase from Aspergillus oryzae.Preparations of soluble and immobilized lactase were evaluated under initial velocity conditions in a batch process. Immobilization had no significant effect on the pH optimum at 50 degrees C or kinetic parameters at pH 4.5 or pH 6.5 and 50 degrees C. At pH 4.5, the soluble enzyme possessed maximum activity at 60 degrees C and the immobilized at 55 degrees C; at pH 6.5 both showed maximum activity at 55 degrees C. The activation energy, entropy, and enthalpy decreased significantly with immobilization at pH 4.5 but not at pH 6.5. When the immobilized enzyme was placed in a packed-bed reactor, the effect of temperature on activity was altered as reflected by a marked decrease in the thermodynamic parameters of activation at both pH levels. Upon immobilization there was also a dramatic increase in the apparent thermal stability of the lactase, and the mean half-life at 50 degrees C was increased from 7.2 to 13 days at pH 4.5 and from 3.8 to 16 days at pH 6.5.