家蚕二化性杂交品种部分数量性状遗传参数的初步评估

采用完全随机设计法根据10头老熟幼虫体重、全茧重、茧层量、茧层率（%）、存活率、万蚕茧层量和茧丝长等指标,对两对二化性家蚕Bombyx mori L. 杂交品系（SH6×NB₄D₂和CSR₂×CSR₄）杂交一代的22个子代个体进行了遗传参数估算,以缩小优质蚕品种的候选范围,并且计算出直接筛选的参数,如遗传力和遗传进度等,使这些信息可用于以筛选高产新品种为目的的育种和选择过程中。杂交子代2, 4, 5, 6, 7, 10, 14, 16, 19和20号个体在这几个指标中表现出显著的优越性。全茧重、万蚕茧层量和茧丝长的遗传力和遗传进度较大,可以简单地从表现型的差异对这些性状进行选择并取得遗传性状改良。其他几个指标(10头老熟幼虫体重、茧层量、茧层率(%)和存活率)的遗传力和遗传进度较低,对这些性状进行直接选择来改良品种的效果较差。     

Detecting lung overdistention in newborns treated with high-frequency oscillatory ventilation.

Positive airway pressure (Paw) during high-frequency oscillatory ventilation (HFOV) increases lung volume and can lead to lung overdistention with potentially serious adverse effects. To date, no method is available to monitor changes in lung volume (DeltaVL) in HFOV-treated infants to avoid overdistention. In five newborn piglets (6-15 days old, 2.2-4.2 kg), we investigated the use of direct current-coupled respiratory inductive plethysmography (RIP) for this purpose by evaluating it against whole body plethysmography. Animals were instrumented, fitted with RIP bands, paralyzed, sedated, and placed in the plethysmograph. RIP and plethysmography were simultaneously calibrated, and HFOV was instituted at varying Paw settings before (6-14 cmH(2)O) and after (10-24 cmH(2)O) repeated warm saline lung lavage to induce experimental surfactant deficiency. Estimates of Delta VL from both methods were in good agreement, both transiently and in the steady state. Maximal changes in lung volume (Delta VL(max)) from all piglets were highly correlated with Delta VL measured by RIP (in ml) = 1.01 x changes measured by whole body plethysmography - 0.35; r(2) = 0.95. Accuracy of RIP was unchanged after lavage. Effective respiratory system compliance (Ceff) decreased after lavage, yet it exhibited similar sigmoidal dependence on Delta VL(max) pre- and postlavage. A decrease in Ceff (relative to the previous Paw setting) as Delta VL(max) was methodically increased from low to high Paw provided a quantitative method for detecting lung overdistention. We conclude that RIP offers a noninvasive and clinically applicable method for accurately estimating lung recruitment during HFOV. Consequently, RIP allows the detection of lung overdistention and selection of optimal HFOV from derived Ceff data.     

Solubilization of human prostatic 5 alpha-reductase

A sensitive assay for 5 alpha-reductase was introduced which is capable of detecting at least 0.2 U of activity per sample. The assay was used in developing a method for the solubilization of human prostatic 5 alpha-reductase. Homogenisation conditions were devised under which 95% of the total prostatic 5 alpha-reductase was released into the microsomal fraction. A combination of 0.1 M sodium citrate, 0.1 M KCl, 20% (v/v) glycerol, 0.5 mM NADPH and 1 microM testosterone was found to stabilise 5 alpha-reductase in the presence of detergents. The effect of the presence of low concentrations of detergents in the assay on the activity of 5 alpha-reductase was studied. Triton X-100, Lubrol PX and Nonidet P-40, caused a concentration-dependent inhibition of activity. The ability of several detergents (Triton X-100 MEGA-9, Tween 20, Tween 80, digitonin, Lubrol PX and Nonidet P-40) to solubilise 5 alpha-reductase was studied. All detergents caused a concentration-dependent solubilization of 5 alpha-reductase. Significant amounts of active solubilized enzyme were recovered only with Lubrol PX at concentrations less than 1.1 mg/ml. Seventy percent of the 5 alpha-reductase was solubilized in an active form by extracting the membranes 3 times with 0.8 mg/ml Lubrol PX.     

Sialomucins at resection margin and likelihood of recurrence in colorectal carcinoma.

Oncogenic transformation of colonic epithelium is accompanied by changes in surface carbohydrate, notably an increased secretion of sialomucins at the expense of the normally predominant sulphomucins. In a multicentre prospective trial the correlation between the presence of sialomucins at the resection margin and the subsequent development of local recurrence was studied in 250 patients who had undergone "curative" resection for colorectal carcinoma with a mean follow up period of 14 months. Nineteen of 70 patients (27.1%) with a sialomucin predominant pattern at either resection margin developed local recurrence compared with 15 of 180 patients (8.3%) with a mixed or sulphomucin predominant pattern (p less than 0.01). Increased sialomucin staining at the resection margins was associated with reduced survival in these patients (p less than 0.01). At a mean of 14 months of follow up 153 patients (85%) were alive in the sulphomucin group and 53 patients (76%) were alive in the sialomucin group. Regression analysis predicted five year survivals of 32.8% and 18.9% for the sulphomucin and sialomucin groups respectively. Abnormal mucus production at the resection margin in patients treated for colorectal carcinoma appears to identify those with a higher risk of local recurrence and reduced survival.     

A fuel cell model in biological energy conversion

Consideration of the high energy conversion efficiency of biological systems leads to the idea that mechanical energy may arise via a series of steps, of which a rate-determining one occurs in a fuel-cell-like element. The mitochondrion is suggested as the site of such entities. The observed efficiency would be consistent with a potential loss of about 0.5 V. The supposed biological fuel cells would be able to act as an electrical power source, driving chemical reactions against their spontaneous direction.Considerations of electrical conductance in wet proteins shows that ohmic (i.e., non-interfacial) potential differences through mitochondrial membranes could be negligible. The cathodic reaction would be the reduction of oxygen, O₂+4H⁺+4e^–H₂O and the anodic reaction, 2NADH⁺2NAD+2H⁺+4e^–. The anodes are suggested as being molecular, buried in the invaginations of the inner membrane forming the cristae. The cathodes are located on enzymes which are probably on the inner side of the membrane but could be, respectively, on the outer (cathodic), and the inner (anodic) sides. The electron transport occurs though proteins within each membrane. The relation of the so-called fuel cell potentials to potentially observable membrane potentials, and those measured by fluorescent probes, are discussed.The fuel cells produce electrical energy and this energy is transferred to ADP by an electrolytic route, using electric power from the cells to work the endergonic ATP synthesis. Possible electrode reactions are suggested. An exponential dependence of the rate of ATP synthesis upon applied potential has been observed.Biological cells radiate electromagnetically in the 10⁹ to 10¹⁵ Hz region. Such phenomena support a fuel cell model of a biological cell because they demand the presence of mobile electrons.     

Mineralization in vitro of matrix formed by osteoblasts isolated by collagenase digestion

Osteoblasts from calvaria of 18-day-old fetal Sprague-Dawley rats were isolated using a dissecting procedure followed by collagenase digestion. Freshly isolated or previously frozen cells were cultured for up to 4 weeks in a Dulbecco's modified Eagle's medium supplemented with 10% fetal calf serum and 50 micrograms/ml ascorbic acid, with or without 10 mM beta-glycerophosphate. Most of the cells were alkaline phosphatase positive throughout the culture period and expressed a type-I collagen as assessed by immunofluorescence. Cells cultured in the presence of beta-glycerophosphate formed a matrix with type-I collagen in 7 days. The matrix underwent mineralization in less than 2 weeks. In the absence of beta-glycerophosphate, only the formation of a nonmineralized matrix was observed. Electron-microscopic examination revealed osteoblasts embedded in a dense network of collagen fibers, with a well-defined mineralization process in association with matrix vesicles. Scanning electron-microscopy showed that the matrix composed of layers of irregularly shaped spread cells with smooth surfaces trapped in a fiber matrix. No mineralization process was observed when rat skin fibroblasts were cultured under similar conditions. These data demonstrate the ability of enzymatically isolated osteoblasts cultured in the presence of beta-glycerophosphate to form bone in vitro, and that this process is similar to bone formation in vivo.     

Increase of oleic acid in erythrocytes associated with malignancies.

Total lipid extracts of erythrocyte cell membranes from 60 patients with documented malignancies, 41 patients with various acute and chronic diseases, and 40 healthy subjects were analysed. The results were expressed as ratios of stearic to oleic acid, reflecting the degree of desaturation of stearic acid. The mean ratios for the healthy subjects and controls without cancer were 1.5 (SD 0.27) and 1.45 (0.28), respectively, whereas the ratios for patients with malignancies were consistently lower than the cut off point of 1.0, with a mean of 0.69 (0.15) (p less than 0.001). The desaturation ratio was also significantly lower (p less than 0.001) in the group with recurrent tumours (mean 0.75 (0.04)) compared with those with no evidence of recurrent tumours (mean 1.55 (0.27)). It is suggested that the increased unsaturation (oleic acid) in the circulating erythrocytes may be useful in the diagnosis and postoperative monitoring of patients with cancer.     

Purification and characterization of secreted acid phosphatase under phosphate-deficient condition inPholiota nameko

Activity of acid phosphatase secreted by mycelia ofPholiota nameko on cultivation for 30d in Pi-depleted medium was 88-fold higher than the corresponding activity in the Pi-supplied medium. One isozyme of the secreted acid phosphatases was purified from the culture filtrate of Pi-depleted medium by ammonium sulfate fractionation and cation exchange chromatography. The purified enzyme was homogeneous on electrophoresis. Gel filtration analysis showed change chromatography. The purified enzyme was homogeneous on electrophoresis. Gel filtration analysis showed that the native molecule had a molecular weight of 117,000. The molecular weight on gel electrophoresis with SDS was 52,000, indicating that the native form of the enzyme was a homodimer. The optimum pH and temperature of the enzyme were, 5.5 and 45°C, respectively, and the isoelectric point of the enzyme was pH 6.9. Adsorption on Con A-Sepharose and periodic-Schiff stain suggested that the enzyme is a glycoprotein. The enzyme hydrolyzed a wide variety of phosphate esters, nucleoside phosphates, sugar phosphates, and phosphorylated amino acids. Cu²⁺, Fe²⁺, Hg²⁺, iodoacetate, molybdate, tartaric acid, and SDS inhibited the enzyme activity. Fe³⁺ (1 mM), Triton X-100, methanol, and ethanol activated it. Fifteen residues of the N-terminal amino acid sequence were determined.     

Reactions of the adult female of the soft scale Kilifia acuminata to some physical factors in laboratory experiments (Homoptera: Coccoidea: Coccidae)

The soft scale insect, Kilifia acuminata (Signoret) reacts positively to light. The simple eyes are the photoreceptors by means of which the insect can sum up the light from various directions and steers in a path towards the high intensity beam. The insect reacts skototactically towards dark objects.
The linear velocity of the insect significantly increases with the increase of temperature. It has a zone of thermopreferendum extending between 22° and 32°C. Above 37°C, the insect is sensitive to small temperature differences of 2°C.
At different humidity combinations below 75% R.H., the insect prefers the moist side, while in the upper range above 83% R.H., it usually prefers the dry side. The preferred zone of humidity extends between 75 and 83%.
Orthokinesis, klinokinesis and klinotaxis are the main mechanisms regulating the insect reaction towards different physical factors.
The insect behaviour and its correlation to the normal environment is also discussed.     

Stimulation of heterotrophic and autotrophic growth ofSphaerotilus discophorus by manganous ions

Growth ofS. discophorus in a casamino acids-mineral salts medium was stimulated 3-fold on addition of 0.05% MnSO₄·H₂O to the medium. Growth was measured by determinations of total nitrogen, protein and DNA on the washed cellular material.Autotrophic growth ofS. discophorus strain 43-R was obtained in an inorganic mineral salts medium supplemented with trace amounts of the essential vitamins, thiamin, biotin and cyanocobalamin and with Mn⁺⁺ as the sole available source of energy. A gas mixture of 5% CO₂-95% air was bubbled continuously through the cultures during incubation. Concomitant with growth, Mn⁺⁺ disappeared from the cultures and MnO₂ was formed.