Female-induced sexual arousal in male mice and rats: behavioral and testosterone response

Exposure of a male mouse to a female mouse separated from it by a holed partition induced specific behavior and an increase in blood testosterone in the male. The male made more approaches to the partition and spent more time at it. The time spent by the male mouse over the first 10 min at the partition, behind which an estrus female was placed, was increased sixfold compared to the time spent by a male mouse exposed to the vacant neighboring compartment; and 1.5-fold compared to that spent by a male mouse exposed to a nonreceptive female or a male. Increased blood testosterone level was detected at 20 min of exposure to a receptive female in winter and at 40 min in summer. No variation in blood testosterone levels in the male mouse exposed to a nonreceptive female or a male was observed. Similar response to a receptive female placed in the neighboring compartment was shown in a male rat. The time spent by the male rat at the partition was 12 times higher when there was an estrus female behind it than in control. Blood testosterone in the male rat increased in response to a female rat and did not change in response to a male rat indicating female-induced motivation. It was concluded that the partition time might serve as a quantitative measure of sexual motivation in the males and that the model of female-induced sexual arousal used was suitable for studying both motivational and hormonal components of sexual arousal in male mice and rats.     

Inter-plot competition in yield trials of potatoes (Solanum tuberosum L.) with single-drill plots

An experiment was carried out to assess the significance of inter-plot competition in a yield trial of potato cultivars. Seventeen cultivars were deliberately chosen and assessed for yield in single-drill and four-drill plots. Inter-plot competition for fresh-weight yield was a significant factor in the single-drill plots. It was modelled using a common competition coefficient with a covariate based on neighbour fresh-weight yields. In contrast, there was no statistically significant inter-plot competition for specific gravity. After adjustment for inter-plot competition, varietal ranking in estimated monoculture yield differed little from that based on unadjusted means. However, there was a reduction in the range of yield estimates, and a closer agreement with the observed pure-stand yields from the inner two drills of the four-drill plots. The adjustment for monoculture performance was most pronounced for the higher and lower yielding varieties, as expected from the assumption that the performance of high yielding varieties was enhanced in a competitive environment at the expense of low yielding ones. A general and flexible method of estimating competition coefficients in variety trials, together with a suitable algorithm, was developed and is explained in an appendix. It was used to check for inter-plot competition in a number of potato trials with single-drill plots and a large number of entries. Competition was found in some trials but not in others. Thus, where potato tubers are grown in single-drill plots for assessment of fresh-weight yield, adjustment should be made for inter-plot competition when evidence of inter-drill competition is found.     

豆豉纤溶酶基因在大肠杆菌中的可溶性表达及纯化(英文)

豆豉纤溶酶是从豆豉中发现的新型纤溶酶.从枯草杆菌DC-12中提取总DNA,PCR法扩增pro-DFE基因.将pro-DFE基因插入载体pET-32a,构建表达质粒pET-pro-DFE,转化大肠杆菌BL21(DE3),对重组菌株进行变温诱导表达,重组菌株于37℃培养至OD600为0.6时,加入终浓度为0.4mmol/L的IPTG于24℃进行诱导,SDS-PAGE显示可溶性重组融合蛋白约占重组蛋白的60%.且少量融合重组蛋白发生自切割,形成成熟的豆豉纤溶酶,破菌上清中含有成熟的豆豉溶栓酶,纤溶活性为200IU/mL.重组酶经纯化后比酶活为1280IU/mg.     

MicroRNA-146a抑制胶质瘤细胞增殖的研究

目的：检测胶质瘤中miR-146a的表达水平,并研究miR-146a对胶质瘤细胞增殖的影响。方法：应用实时定量PCR的方法检测胶质瘤组织和癌旁组织中miR-146a的表达水平,采用脂质体细胞转染miRNA模拟物的方式过表达miR-146a,MTT法检测转染后细胞的增殖率,利用在线软件targetScan预测miRNA可能的靶基因。结果：miR-146a在胶质瘤组织中表达明显降低（P〈0.01）,相对表达水平为癌旁组织的35%,细胞转染miR-146a模拟物后,miR-146a表达明显增加,癌细胞增殖率明显降低（P〈0.01）,仅为原细胞的47%。Notch1基因是miR-146a影响胶质瘤细胞增殖活力的可能靶基因。结论：miR-146a可能通过抑制Notch1基因的表达调控胶质瘤细胞的增殖。     

Fluid consumption in lithium-treated rats: Roles of stimulus novelty and context novelty

In 5 experiments thirsty rats received an injection of lithium chloride or of saline, and their consumption of fluid was monitored at 5-min intervals for 30min. The novelty of the fluid and the novelty of the test context was varied. In Experiment 1 a novel fluid (a sucrose solution) was offered in a novel context; in Experiment 2 the fluid was novel and the context was familiar (the home cage); in Experiment 3 the fluid was familiar and the context was novel; and in Experiment 4 both fluid and context were familiar. Lithium influenced fluid consumption in those designs that included at least one novel feature (Experiments 1, 2, and 3, but not in Experiment 4). Consumption was initially enhanced (with respect to the controls) when the context was novel, but was suppressed when the fluid was novel. In Experiment 5, the flavor was over-ingested after lithium treatment when it was presented in a short (5min) test conducted in a novel place, but was rejected in a subsequent consumption in the home cages. It is argued that the effect of lithium depends on two factors: enhanced attention to salient cues that modifies the exploratory responses evoked by a novel context; rapid conditioning of an aversion when the fluid consumed is novel. Implications for the use of fluid consumption as an index of lithium-induced nausea are considered.     

Copper removal from an industrial waste by bioleaching

Summary Copper contained in a solid industrial waste produced in a silicone manufacturing process was leached with spent iron medium from aThiobacillus ferrooxidans culture. Most effective leaching was observed in a continuously fed, dual reactor system. Spent iron medium was generated by growingT. ferrooxidans in 0.9 K iron medium at pH 1.5 in the first reactor, and was transferred to a second reactor in which it leached the copper from the waste. Leaching was effective at a pulp density of the waste material as high as 20%. In experiments run at a pulp density of 2.5%, the spent iron medium was most efficient in leaching copper when it was first diluted 100-fold with a mineral salts solution at pH 1.5. Removal of the copper from the waste appeared to involve its displacement by acid, dissolved mineral salts, and ferric iron. Potentials for practical application of this process are discussed.     

光肩星天牛的脑部结构

通过Mallory和HE染色,对光肩星天牛Anoplophora glabnpenn脑部显微结构进行了观察.结果表明,光肩星天牛的脑由前脑、中脑、后脑三部分组成.前脑叶髓层包括一对蕈形体、一个中央体、一个脑桥体和一对附叶,其中每个蕈形体仅有一个帽状的蕈体冠.中脑触角叶较大,由九簇放射状排列的触角神经束组成,中央的一束较粗,说明其嗅觉发达.后脑较小.     

Hydrolysis of triglyceride by the whole cell of Pseudomonas putida 3SK in two-phase batch and continuous reactors systems

Batch and continuous hydrolysis of olive oil in an organic-aqueous two-phase system using the live whole cell of Pseudomonas putida 3SK as a source of a lipase is investigated. The strain was not only fully viable and grown well, but also produced extracellular lipase simultaneously. The degree of hydrolysis, depending on olive oil concentration in the solvents, was maximal at 13.5% (w/v) and decreased with the increase of the substrate concentration. At the optimal condition, a degree of hydrolysis higher than 95% was achieved with 24 h at 30 degrees C when the reaction was carried out in a two-phase batch stirred reactor. For long-term operation a continuous stirred reactor was designed. When the reaction was carried out in a continuous stirred reactor, the degree was hydrolysis reached 86% at a dilution rate of 0.2 h(-1). Satisfactory performance of a two-phase bioreactor was obtained in a long-term continous operation, which lasted for at least 30 days by feeding organic solvent containing olive oil and aqueous media separately. (c) 1994 John Wiley & Sons, Inc.     

Flower-inducing and -inhibiting activities of Phloem Exudate from Cotyledons of Pharbitis Seedlings

The flower-inducing and -inhibiting activities of phloem exudate (PE) prepared from cotyledons of Pharbitis seedlings were examined, using apex cultures in vitro from Pharbitis as a bioassay system.The PE was prepared from photoperiodically-induced cotyledons (SD-PE). The SD-PE was subjected to the following fractionations: When the SD-PE was extracted with CHCl₃ and then ethyl acetate, the inducing activity was located in the final aqueous fraction. The activity was localized in the diffusate when the aqueous fraction was dialyzed (molecular weight cut off was 10,000). The diffusate was fractionated by ion exchange chromatography, and flower-inducing activity was found in the fraction adsorbed onto anion exchange resin. When the fraction was applied to a Sep-Pak C18 cartridge, the activity eluted with 25% MeOH. As a result of the above fractionation, activity was increased about 30-fold.The nature of the flower-inhibiting activity of the PE taken from cotyledons exposed to continuous-light conditions was examined (CL-PE). The inhibiting activity was decreased as the cotyledons were exposed to longer dark periods; it appeared to be heat-stable. The CL-PE also inhibited flowering in Lemna. The CL-PE was subjected to the following fractionations: When the CL-PE was extracted with CHCl₃ and ethyl acetate, activity was located in the final aqueous fraction. Activity was localized in the diffusate when the aqueous fraction was dialyzed (molecular weight cut off was 10,000). When the diffusate was fractionated by ion exchange chromatography, the activity was found in the flow-through fraction. When the fraction was applied to a hydroxyapatite cartridge, the activity eluted with 25 mM sodium phosphate buffer. When the fraction was re-dialyzed (molecular weight cut off was 1,000), the diffusate contained the activity. As a result of the above fractionation, activity was increased about 10-fold.     

Stability of bilirubin oxidase in organic solvent media: a comparative study on two low-water systems

The storage stability of bilirubin oxidase was studied in water-in-oil CTAB microemulsions with a chloroformrich continuous organic phase. The kinetics of the inactivation process were best described by a double exponential equation. Approximately half of enzymatic activity was lost during a "fast" phase with a half life of ca. 50 min, whereas the remaining activity was lost much more slowly (half life ca. 1000 min). Rates of inactivation were not affected significantly by variation of either solvent composition or concentration of water droplets, but inactivation was more rapid when droplet size was very small. Steady-state enzyme kinetics were studied at various stages in the inactivation process, and it was shown that inactivation occurred without change in the K(m) of the enzyme for bilirubin. Stability was also studied in a liquid/solid two-phase system; it was found that the inactivation process in this system; it was found that the inactivation process in this system was best described by a single exponential term. The rate was similar to the "fast" phase rate observed in the water-in-oil microemulsion system. Inactivation of the enzyme slow. Addition of the surfactant CTAB to the aqueous environment increased the rate of inactivation to levels comparable to those of the "slow" phase observed in water-in-oil microemulsions. (c) 1993 Wiley & Sons, Inc.     

Phosphatidylcholine metabolism in ischemic and hypoxic hearts

The rates of phosphatidylcholine biosynthesis in the isolated hamster hearts under ischemic and hypoxic conditions were examined. Global ischemia was produced by perfusion of the heart with a reduced flow, whereas hypoxia was produced by perfusion with a N₂-saturated buffer. A 51% reduction in the biosynthesis of phosphatidylcholine was observed in the ischemic heart. The reduction was caused by a severe decrease in ATP level which resulted in a diminished conversion of choline into phosphocholine. A 22% reduction in the biosynthetic rate of phosphatidylcholine was also detected in the hypoxic heart. The reduction was caused by a diminished level of CTP which resulted in a decreased conversion of phosphocholine to CDP-choline. No compensatory mechanism was triggered during ischemia, but the CTP: phosphocholine cytidylyltransferase activity was enhanced in the hypoxic heart. Our results demonstrate the possible rate-limiting role of choline kinase and reconfirm the regulatory role of the cytidylyltransferase in the biosynthesis of phosphatidylcholine. (Mol Cell Biochem116: 53–58, 1992)     

Effect of including genetic progress in milk yield on evaluating the use of sexed semen and other reproduction strategies in a dairy herd

The objective of this study was to explore the importance of including genetic progress in milk yield when evaluating different reproductive strategies in a dairy herd by simulation modeling. The model used in this study was SimHerd V, a dynamic and mechanistic Monte Carlo simulation model of a dairy herd including young stock. A daily increasing trend describing genetic milk yield potential of the sire population was included in the model. The inaccuracy of assuming that replacement heifers have the same (milk yield) potential as the cows present in the herd was hereby dealt with. Improving estrus detection rate from 0.45 to 0.80 increased gross margin (GM) per cow-year by €20 when genetic progress was not included in the model. When genetic progress was included in the model, then the same improvement in estrus detection decreased the GM per cow-year by €7.4. This reduced effect was explained by a lower replacement rate in consequence of the improved estrus detection and thereby a slower genetic progress in the herd. There was a reduced effect of including genetic progress on GM when surplus heifers were sold selectively based on breeding values. Repeated insemination with sexed semen on the superior half of all heifers reduced GM by €8 per cow-year when genetic progress was not included and increased the GM by €16 per cow-year when genetic progress was included in the model. Including genetic progress reduced the losses caused by lower conception and estrus detection rates and had a minimal effect with regard to postponing first insemination. This study has proven that it is important to include genetic progress in decisions on reproduction strategies in a dairy herd.     

青冈常绿阔叶林钾的生物循环研究

本文对分布于浙江建德的青冈常绿阔叶林K的生物循环进行了研究。群落各代表种类的K浓度大都在0．2～0．4％之间,其令藤本、草本＞下木层＞乔木层、亚乔木层植物,各器官中K浓度叶＞枝、根＞干。青冈中K浓度为下木层＞乔木层＞亚乔木层;幼嫩、同化和生殖器官中积累了较多的K。凋落物凋落之前,K有被回输的现象。K在群落中现存量为431．64kg／hm2,死地被层中积累量为25．88ky／hm2,土壤（A0－B层）中储存量为64298kg／hm2。群落K的存留量为53．83ky／hm2.a;归还量为51．89ky／hm2．a,其中大部分通过穿透水归还（占70％）;吸收量为105．72kg／hm2．a。降水输入了7．10kg／hm2．a的K。与世界上其它森林类型相比,青冈林K的循环速申和利用效申是对一定水热条件的正常反映。     

Cardiovascular and respiratory responses associated with limb autotomy in the blue crab, Callinectes sapidus

Cardiovascular and respiratory variables were recorded in the blue crab, Callinectes sapidus, during injury and subsequent autotomy of a chela. Cardiac function and haemolymph flow rates were measured using a pulsed-Doppler flowmeter. Oxygen uptake was recorded using an intermittent flow respirometry system. Crabs reacted to the loss of a chela with a rapid increase in heart rate, which was sustained for 2 h. Stroke volume of the heart also increased after the chela was autotomized. A combined increase in heart rate and stroke volume led to an increase in cardiac output, which was maintained for an hour after the loss of a chela. There was also differential haemolymph perfusion of various structures. There was no change in perfusion of the anterolateral arteries or posterior and anterior aortae, during injury of the chela or subsequent autotomy. Haemolymph flow rates did increase significantly through the sternal artery during injury and immediately following autotomy of the chela. This was at the expense of blood flow to the digestive gland: a sustained decrease in haemolymph flow through the hepatic arteries occurred for 3 h following autotomy. Fine-scale cardiac changes associated with the act of autotomy included a bradycardia and/or associated cardiac pausing before the chela was shed, followed by a subsequent increase in cardiac parameters. Changes in the cardiovascular physiology were paralleled by an increase in oxygen uptake, which was driven by an increased ventilation of the branchial chambers. Although limb loss is a major event, it appears that only acute changes in physiology occur. These may benefit the individual, allowing rapid escape following autotomy with a subsequent return to normal activity.     

Synthesis of phosphatidylcholine with defined fatty acid in the sn-1 position by lipase-catalyzed esterification and transesterification reaction

The incorporation of caproic acid in the sn-1 position of phosphatidylcholine (PC) catalyzed by lipase from Rhizopus oryzae was investigated in a water activity-controlled organic medium. The reaction was carried out either as esterification or transesterification. A comparison between these two reaction modes was made with regard to product yield, product purity, reaction time, and byproduct formation as a consequence of acyl migration. The yield in the esterification and transesterification reaction was the same under identical conditions. The highest yield (78%) was obtained at a water activity (a(w)) of 0.11 and a caproic acid concentration of 0.8 M. The reaction time was shorter in the esterification reaction than in the transesterification reaction. The difference in reaction time was especially pronounced at low water activities and high fatty acid concentrations. The loss in yield due to acyl migration and consequent enzymatic side reactions was around 16% under a wide range of conditions. The incorporation of a fatty acid in the sn-1 position of PC proved to be thermodynamically much more favorable than the incorporation of a fatty acid in the sn-2 position.     

Role of methylation in aerotaxis in Bacillus subtilis.

Taxis to oxygen (aerotaxis) in Bacillus subtilis was characterized in a capillary assay and in a temporal assay in which the concentration of oxygen in a flow chamber was changed abruptly. A strong aerophilic response was present, but there was no aerophobic response to high concentrations of oxygen. Adaptation to a step increase in oxygen concentration was impaired when B. subtilis cells were depleted of methionine to prevent methylation of the methyl-accepting chemotaxis proteins. There was a transient increase in methanol release when wild-type B. subtilis, but not a cheR mutant that was deficient in methyltransferase activity, was stimulated by a step increase or a step decrease in oxygen concentration. The methanol released was quantitatively correlated with demethylation of methyl-accepting chemotaxis proteins. This indicated that methylation is involved in aerotaxis in B. subtilis in contrast to aerotaxis in Escherichia coli and Salmonella typhimurium, which is methylation independent.     

Study on the Photosynthetic Characteristics of Eucommia ulmoides Leaves

A field study on the photosynthetic characteristics in Eucommia ulmoides Oliv. was conducted using a LI-6200 Portable Photosynthesis Analysis System as a measuring device and the modified half-leaf method. It was revealed that the light-saturating photosynthetic rate measured in leaves was in a range of 6~10 μmol CO2 · m-2 · s-1, and the lowest apparent quantum requirement was about 17. The CO2 compensation concentration of photosynthesis was a little more than 100μmol · mol-1 indicating that E. ulmoides was a C3 type plant. Besides stomatal limitation, photoinhibition of photosynthesis was a possible cause of the midday depression in photosynthetic rate. Only about 14 percent of the photosynthetic product was transported from the leaves during photosynthesis.     

Obesity and Malnutrition in a Shantytown Population in the City of São Paulo,Brazil

To investigate the prevalence of obesity and malnutrition in the poor Brazilian population we conducted a survey on the socioeconomic and nutritional status of 535 families (comprising 2 411 individuals) living in shanty towns in the city of São Paulo. There was a 30% prevalence of malnutrition in the children, with chronic malnutrition as the most predominant problem. The prevalence of obesity was 6.4% in boys and 8.7% in girls. Overweight and obesity associated with stunting was found in 5.8% of boys and 6.8% girls. Adolescents showed a higher prevalence of malnutrition when weight-for-age distribution was used (boys 46.4%, girls 40.2%), but a right deviation in the distribution was observed with an increase in obesity and a decrease of malnutrition was observed (obesity was 21% in girls and 8.8% in boys; malnutrition was 15.5% in boys and 12.6% in girls) when the weight-for-height adjustment was made. Stunting was the most predominant type of malnutrition in both sexes. Obesity associated with stunting was more common than obesity without stunting, both in younger children and adolescents. Adults had a higher prevalence of obesity than malnutrition according to both the Metropolitan Life Insurance tables (1.7% of undernutrition, 16.7% of overweight, and 14.1% of obesity) and Body Mass Index (8.5% of undernutrition, 21.9% of overweight, and 14.6% of obesity). There was an increase in the percentage of obese children when at least one adult in the family was obese and an increased percentage of malnourished children when undernourished adults were present in the family. Obesity among the adults of the family decreased the occurrence of malnutrition among the children. In 9% of families there was a coexistence of obesity in the adults and malnutrition in the children. These results demonstrate a coexistence of malnutrition and obesity in poor urban Brazilian communities.     

Protein and collagen content of rat skeletal muscle following space flight

Summary Biochemical determinations of non-collagenous protein and hydroxyproline were made on rat skeletal muscles following 7 days of space flight aboard the NASA space shuttle mission SL-3. Relative to ground-based controls, the wet weight of each experimental muscle was significantly reduced. This was concomitant with a reduction in noncollagenous protein in the muscles. Protein concentration, however, was reduced only in slow-twitch muscles. The effect of space flight on the concentration and hydroxyproline content was different among the muscles. As a result, the loss of muscle mass in some muscles was the consequence of a reduction in both collagenous and non-collagenous proteins, while in others it was primarily the result of a non-collagenous protein loss.