Interactive effects of some environmental and physiological variables on fluorescent age pigment accumulation in brain and heart tissues of an aquatic poikilotherm

Synopsis The present study was undertaken to determine the effects of temperature, ration level, photoperiod, and clutch on variation of fluorescent age-pigment (FAP) accumulation in brain and heart tissues of the freshwater teleost,Puntius conchonius. Two experiments were designed, one testing temperature and ration interactions, the other testing temperature and photoperiod interactions. Three non-sibling clutches were used in each experiment. Temperature affected FAP levels in brain and heart in both experiments, but in a different manner. Brain FAP was inversely correlated with rearing temperature in both experiments. Conversely, heart FAP was directly affected. Ration level affected FAP through body size effects, however, statistical analysis of this observation was not possible. Photoperiod had no significant effect on FAP in either tissue. Significant FAP differences were detected between non-sibling fish, implicating genomic variation in the rate of FAP genesis. The mixed effects of temperature on FAP in each tissue indicates involvement of factors other than metabolic rate in the formation of FAP products. It is proposed that homeoviscous adaptation via modification of cellular lipid constituents may affect the potential for lipid peroxidation and FAP formation in each tissue type at different temperatures.     

Effects of nitrite-induced methaemoglobinaemia on oxygen affinity of carp blood

Synopsis The oxygen transport characteristics and the acid-base status of carp blood was studied in vitro by equilibration of blood samples with and without addition of 5mmol l^–1 of nitrite for 30 min at various Po₂ values in combination with Pco₂ of 1.5 and 5.7mmHg (0.2 and 0.76kPa). After equilibration pH, Po₂, Pco₂, and Co₂ as well as methaemoglobin and HCO₃ ^– concentration were determined and oxygen dissociation curves established. At Pco₂ of 1.5mmHg (0.2kPa) oxygen affinity, expressed by a normal P₅₀ of 3.3mmHg (0.44kPa) was unaffected by nitrite exposure, whereas at Pco₂ 5.7 (0.76kPa), nitrite exposure shifted P₅₀ from 7.59mmHg (1.01kPa) to 21.9mmHg (2.92kPa). Methaemoglobin formation was greater at the higher Pco₂ and increased with falling Po₂. Erythrocyte shrinkage and rising plasma [HC0₃ ^–] during nitrite exposure indicated that the erythrocyte osmoregulation was significantly affected. The present results indicate significantly reduced oxygen affinity upon exposure of carp blood to nitrite. This result contrasts with findings in mammalian blood, where oxygen affinity is greatly enhanced.     

A carbon-13 nuclear magnetic resonance investigation of the metabolic fluxes associated withy glucose metabolism in human erythrocytes

We have used [2-¹³C]d-glucose and carbon-13 nuclear magnetic resonance (NMR) spectroscopy to investigate metabolic fluxes through the major pathways of glucose metabolism in intact human erythrocytes and to determine the interactions among these pathways under conditions that perturb metabolism. Using the method described, we have been able to measure fluxes through the pentose phosphate pathway, phosphofructokinase, the 2,3-diphosphoglycerate bypass, and phosphoglycerate kinase, as well as glucose uptake, concurrently and in a single experiment. We have measured these fluxes in normal human erythrocytes under the following conditions: (1) fully oxygenated; (2) treated with methylene blue; and (3) deoxygenated. This method makes it possible to monitor various metabolic effects of stresses in normal and pathological states. Not only has ¹³C-NMR spectroscopy proved to be a useful method for measuring in vivo flux through the pentose phosphate pathway, but it has also provided additional information about the cycling of metabolites through the non-oxidative portion of the pentose phosphate pathway. Our evidence from experiments with [1-¹³C]-, [2-¹³C]-, and [3-¹³C]d-glucoses indicates that there is an observable reverse flux of fructose 6-phosphate through the reactions catalyzed by transketolase and transaldolase, even in the presence of a net flux through the pentose phosphate pathway.     

Involvement of fibronectin during epiboly and gastrulation in embryos of the common carp,Cyprinus carpio

Summary The present report firstly describes a pilot study in which, during early development of embryos of the common carp, Cyprinus carpio, the cellular adhesion to fibronectin (FN) was blocked by administration of GRGDS peptide (which binds to the FN-receptor). As this treatment resulted in developmental aberrations, suggesting a functional role for FN, the major part of the work was focussed on the distribution of reactivity of anti-FN antibodies during epiboly and gastrulation. GRGDS treatment had a concentration dependent effect on development. Incubation of embryos in 1.5 mg/ml from the 32-cell stage onwards caused a retardation of epiboly, which did not proceed beyond 60%. The embryos did not show involution, as was confirmed by histological study. These preliminary results suggest that FN is involved in both epiboly and gastrulation of carp embryos. During cleavage, no specific extracellular binding of anti-FN antiserum could be observed. However, binding to a number of cell membranes took place from early epiboly onwards. After the onset of gastrulation, we observed a gradually increasing number of the deepest epiblast cells, showing immunostaining on part of their surface, facing the yolk syncytial layer (YSL) or the involuted cells. During early epiboly, anti-FN binding was restricted to areas in front of the migratory hypoblast cells. Later on, binding was found at the border of hypoblast and epiblast cells. At 100% epiboly, some contact areas of epiblast and hypoblast showed a discontinuous lining of reactivity, whilst other areas appeared devoid of anti-FN binding sites. The results indicate that FN is involved in the migration and guidance of hypoblast cells during gastrulation in carp. Correspondence to: P. Gevers     

血糖控制水平与2型糖尿病患者根尖周病的相关关系研究

摘要 目的：探讨血糖控制水平与2型糖尿病合并根尖周病的相关性。方法：回顾性选择2018年9月～2022年9月我院收治的300例2型糖尿病患者临床资料,根据是否发生根尖周病将患者分为根尖周病组（45例）和对照组（255例）,根据糖化血红蛋白（HbA1c）分为血糖控制不佳组（HbA1c≥6.5%,105例）,血糖控制良好组（HbA1c＜6.5%,195例）。多因素Logistic回归分析2型糖尿病合并根尖周病的相关因素,受试者工作特征曲线（ROC）分析HbA1c诊断2型糖尿病合并根尖周病的价值。结果：血糖控制不佳组根尖周病发病率（28.57% vs 7.69%）、PAI评分（2.66±0.41分 vs1.24±0.26分）均高于血糖控制良好组（P＜0.001）。根尖周病组吸烟史比例、牙周疾病比例、血糖控制不佳比例、FPG高于对照组（P＜0.001）,2型糖尿病病程长于对照组（P＜0.001）,服用二甲双胍比例低于对照组（P＜0.01）。多因素Logistic回归结果显示血糖控制不佳、吸烟史是2型糖尿病患者合并根尖周病的危险因素（P＜0.001,P＜0.01）,服用二甲双胍是保护因素（P＜0.001）。HbA1c诊断2型糖尿病患者合并根尖周病的曲线下面积为0.659（95%CI：0.650-0.756, P＜0.01）,灵敏度为73.33%,特异度为62.75%,约登指数为0.3608。结论：血糖控制不佳可能与2型糖尿病患者根尖周病的发生有关,临床应积极控制血糖水平以阻止根尖周病的发生。     

Mutations affecting pigmentation and shape of the adult zebrafish

 Mutations causing a visible phenotype in the adult serve as valuable visible genetic markers in multicellular genetic model organisms such as Drosophila melanogaster, Caenorhabditis elegans and Arabidopsis thaliana. In a large scale screen for mutations affecting early development of the zebrafish, we identified a number of mutations that are homozygous viable or semiviable. Here we describe viable mutations which produce visible phenotypes in the adult fish. These predominantly affect the fins and pigmentation, but also the eyes and body length of the adult. A number of dominant mutations caused visible phenotypes in the adult fish. Mutations in three genes, long fin, another long fin and wanda affected fin formation in the adult. Four mutations were found to cause a dominant reduction of the overall body length in the adult. The adult pigment pattern was found to be changed by dominant mutations in wanda, asterix, obelix, leopard, salz and pfeffer. Among the recessive mutations producing visible phenotypes in the homozygous adult, a group of mutations that failed to produce melanin was assayed for tyrosinase activity. Mutations in sandy produced embryos that failed to express tyrosinase activity. These are potentially useful for using tyrosinase as a marker for the generation of transgenic lines of zebrafish. Received: 17 June 1996 / Accepted: 15 July 1996     

鱼类精子携带的外源基因导入

将鲤鱼（或泥鳅）精子在保存液内与人生长激素（ｈＧＨ）重组质粒ＤＮＡ保温,再与鲤（或泥鳅）卵受精。由此发育的鱼苗经ＤＮＡ分子杂交和ＰＣＲ检测证明,３３．３％（或３７．０％）的个体带ｈＧＨ基因,其拷贝数在４—１５０／细胞之间。在一定条件下,精子可作为携带外源基因的载体,通过受精作用产生转基因鱼。     

我国西北地区49例Hb G Coushatta的分布——东北亚古代游牧民族的遗传标志

本文报道49例Hb G Coushatta在我国西北部的分布情况。新疆和甘肃的发生率为0.57‰和0.43‰,高于陕西的发生率0.07‰。维吾尔、哈萨克、柯尔克孜和回族的发生率为0.66‰—1.74‰,高于汉族的发生率0.45‰。Hb G Coushatta基因流呈由北向南和向西漂移和特点,结合国内外有关资料进行分析,这种变异体起源于东北亚地区,为古代游牧民族的遗传标志。     

Easel, a gypsy LTR-retrotransposon in the Salmonidae

Despite the close similarities between retroviruses and the gypsy/Ty3 group of LTR-retrotransposons their host ranges are largely distinct: the retroviruses are found only in vertebrates, whereas the gypsy LTR-retrotransposons are almost exclusively restricted to invertebrates, plants and fungi. Here we report the amplification by PCR, and characterisation, of one of the first LTR-retrotransposons to be discovered in vertebrates - in several members of the piscine family Salmonidae. Phylogenetic analysis of this retroelement, termed easel, indicates that it is probably a phylogeneticaly basal member of the gypsy group of LTR-retrotransposons and occurs in some of the same species from which retroviruses have previously been isolated. Thus some members of the Salmonidae are the first organisms known to harbour both retroviral branch elements and the gypsy LTR-retrotransposon branch elements. This creates an overlap in the host ranges of the two retroelement families.