芜菁的诱导同源四倍体减数分裂分析

细胞学上芜菁 (Brassicarapa)为正常的二倍体 ,具有 1 1的联会和 1 - 1的染色体分离。它的花粉母细胞 (PMC’s )在小孢子发生过程中的减数分裂前期 (M1 )无“B染色体” ,也无任何次级缔合。用 0 0 2 %的秋水仙碱水溶液处理 6h对多倍体的诱导形成明显。诱导出的同源四倍体构型中无联会基因 ,而成 1或 2次交叉的二价体、三价体和四价体。从多倍体逆转的有趣现象中发现 ,4 6 7%的诱导多倍体后来恢复成二倍体。不平衡的染色体分离普遍存在于诱导出的同源四倍体中 ,这就是导致生存能力不同的异常配子体出现的主要原因。异常配子体的结合 ,在芸苔属 (Brassica)现存种的演化中起到了重要作用     

Occurrence of cestodes and comparative efficacy of Typha angustata and sulphadimidine against cestodes in Columba livia domestica (Domestic Pigeon)

The occurrence of intestinal parasites of Columba livia domestica has been on the increase, leading to high economic and production losses with more fatal cases. This study was designed to investigate the prevalence of cestodes in pigeons and determine the efficacy of Typha angustata extract and sulphadimidine against these cestodes in the domestic pigeon. A total of 30 pigeons were examined. 18 (60%) pigeons were found infected with only one type of cestode species (Raillietina spp.). The difference in prevalence between males and females was statistically significant (χ² = 8.167, p = 0.004). The mean EPG count in group A (treated with T. angustata extract) before treatment and after treatment was 176 ± 4.33 and 155 ± 4.24, respectively. In group B (treated with sulphadimidine), the mean EPG calculated before treatment and after treatment was 184 ± 6.74 and 35 ± 3.53, respectively. The efficacy at day 28 of T. angustata and Sulphadimidine was 11.93% and 80.97%, respectively. It was concluded on the basis of the EPG and efficacy data that T. angustata extract had low efficacy against raillietiniasis, while as sulphadimidine, which is also used before to treat different intestinal parasites, had a good efficacy against raillietiniasis. Further studies are required to know the prevalence of other gastrointestinal parasites in pigeons and efficacy of different medicinal plants against such parasites.     

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.     

Sodium azide dilates coronary arterioles via activation of inward rectifier K+ channels and Na+-K+-ATPase

Sodium azide (NaN(3)), a potent vasodilator, causes severe hypotension on accidental exposure. Although NaN(3) has been shown to increase coronary blood flow, the direct effect of NaN(3) on coronary resistance vessels and the mechanism of the NaN(3)-induced response remain to be established. To address these issues without confounding influences from systemic parameters, subepicardial coronary arterioles were isolated from porcine hearts for in vitro study. Arterioles developed basal tone at 60 cmH(2)O intraluminal pressure and dilated acutely, in a concentration-dependent manner, to NaN(3) (0.1 microM to 50 microM). The NaN(3) response was not altered by the nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester or endothelial removal. Neither inhibition of phosphoinositol 3-kinase and tyrosine kinases nor blockade of ATP-sensitive, Ca(2+)-activated, and voltage-dependent K(+) channels affected NaN(3)-induced dilation. However, the vasomotor action of NaN(3) was significantly attenuated in a similar manner by the inward rectifier K(+) (K(IR)) channel inhibitor Ba(2+), the Na(+)-K(+) ATPase inhibitor ouabain, or the guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one (ODQ). Ba(2+), in combination with either ouabain or ODQ, nearly abolished the vasodilatory response. However, there was no additive inhibition by combining ouabain and ODQ. The NaN(3)-mediated vasodilation was also attenuated by morin, an inhibitor of phosphatidylinositolphosphate (PIP) kinase, which can regulate K(IR) channel activity. With the use of whole cell patch-clamp methods, NaN(3) acutely enhanced Ba(2+)-sensitive K(IR) current in isolated coronary arteriolar smooth muscle cells. Collectively, this study demonstrates that NaN(3), at clinically toxic concentrations, dilates coronary resistance vessels via activation of both K(IR) channels and guanylyl cyclase/Na(+)-K(+)-ATPase in the vascular smooth muscle. The K(IR) channels appear to be modulated by PIP kinase.     

Biochemical and molecular characterization of a lipase produced by Rhizopus oryzae

A novel strain of Rhizopus oryzae WPG secretes a noninduced lipase (ROLw) in the culture medium; purified ROLw is a protein of 29 kDa, the 45 N-terminal amino acid residues were sequenced, this sequence is very homologous to Rhizopus delemar lipase (RDL), Rhizopus niveus lipase (RNL) and R. oryzae lipase (ROL29) sequences; the cloning and sequencing of the part of the gene encoding the mature ROLw, shows two nucleotides differences with RDL, RNL and ROL29 sequences corresponding to the change of the residues 134 and 200; ROLw does not present the interfacial activation phenomenon when using tripropionin or vinyl propionate as substrates; the lipase activity is maximal at pH 8 and at 37 degrees C, specific activities of 3500 or 900 U mg(-1) were measured at 37 degrees C and at pH 8, using olive oil emulsion or tributyrin as substrates, respectively; ROLw is unable to hydrolyse triacylglycerols in the presence of high concentration of bile salts; it is a serine enzyme as it is inhibited by tetrahydrolipstatin and was stable between pH 5 and pH 8.     

Inhaled marijuana smoke disrupts mitochondrial energetics in pulmonary epithelial cells in vivo

Habitual marijuana smoking is associated with inflammation and atypia of airway epithelium accompanied by symptoms of chronic bronchitis. We hypothesized that Delta(9)-tetrahydrocannabinol (THC), the primary psychoactive component of marijuana, might contribute to these findings by impairing cellular energetics and mitochondrial function. To test this hypothesis, we examined particulate smoke extracts from marijuana cigarettes, tobacco cigarettes, and placebo marijuana (0% THC) cigarettes for their effects on the mitochondrial function of A549 cells in vitro. Only extracts prepared from marijuana cigarettes altered mitochondrial staining by the potentiometric probe JC-1. With the use of a cross-flow, nose-only inhalation system, rats were then exposed for 20 min to whole marijuana smoke and examined for its effects on airway epithelial cells. Inhalation of marijuana smoke produced lung tissue concentrations of THC that were 8-10 times higher than those measured in blood (75 +/- 38 ng/g wet wt tissue vs. 9.2 +/- 2.0 ng/ml), suggesting high local exposure. Intratracheal infusion of JC-1 immediately following marijuana smoke exposure revealed a diffuse decrease in lung cell JC-1 red fluorescence compared with tissue from unexposed or placebo smoke-exposed rats. Exposure to marijuana smoke in vivo also decreased JC-1 red fluorescence (54% decrease, P < 0.01) and ATP levels (75% decrease, P < 0.01) in single-cell preparations of tracheal epithelial cells. These results suggest that inhalation of marijuana smoke has deleterious effects on airway epithelial cell energetics that may contribute to the adverse pulmonary consequences of marijuana smoking.     

Acquired antigenicity of DNA after modification with peroxynitrite

There are many contaminants affecting human beings, the most important being the metabolites of gases in air around us or certain deleterious by products from metabolic activity. They are reactive species of nitrogen, oxygen and their derivatives. Nitrogen is taken into body as nitrates, nitrites, peptides, proteins, etc. and its metabolites include higher oxides of nitrogen and peroxynitrite. Although NO is a free radical, it is probably insufficiently reactive to attack DNA directly. By contrast its derivatives N2O3, HNO2, ONOO- can nitrate, deaminate, cause strand breaks in DNA leading to serious consequences including mutations. The study exploits this property of ONOO-, such that on modification DNA which in its native form is non-immunogenic acquires the ability to elicit immune response in experimental animals. The extent of modifications, characterization of induced antibodies along with antigen-antibody interactions are studied and analyzed through different techniques.