马铃薯醇溶蛋白电泳分析方法的建立

[目的]探索并建立马铃薯醇溶蛋白酸性聚丙烯酰胺凝胶电泳(A-PAGE)方法和谱带分析技术.[方法]用25% 2-氯乙醇提取马铃薯醇溶蛋白,借助酸性聚丙烯酰胺凝胶电泳方法对马铃薯醇溶蛋白进行分析,电泳采用浓度12.4%聚丙烯酰胺凝胶,考马斯亮蓝染色.[结果]不同品种都显示出各自特有的醇溶蛋白带谱组合,且清晰可辨.[结论]酸性凝胶电泳技术可用于马铃薯醇溶蛋白分析,具有快速、分辨率高、重复性好等特点,可为马铃薯品种(系)选育提供一种十分有效的方法.     

Changes in the location of polyphenol oxidase in potato (Solanum tuberosum L.) tuber during cell death in response to impact injury: comparison with wound tissue

In order to elucidate the nature of the response of potato to impact injury at the biochemical level, changes in the location of the enzyme responsible for the discoloration, polyphenol oxidase, were determined using immunogold location with an antibody specific for potato tuber polyphenol oxidase. Tissue printing revealed that the enzyme was distributed throughout the tuber. Following impact injury, both tissue printing and quantitative electron microscopy indicated that there was no increase in the level of the enzyme although there was subcellular redistribution of polyphenol oxidase. This redistribution was first apparent at 12 h after impact, as determined by the use of confocal immunolocation, and coincided with loss of membrane integrity. These changes were examined in parallel with a number of stress-related parameters in both impact and wound responses. Wounding was accompanied by active gene expression and protein synthesis, leading to metabolic activity and tissue repair. In contrast, the bruising response was characterised by a limited active response and vital-staining methods indicated that after 16 h the tissue undergoes cell death.     

Cloning and characterization of plastid ribosomal protein S16 gene from potato (Solanum tuberosum L. cv Désirée)

STUDY OBJECTIVE: To determine whether an intensive educational campaign of emergency department personnel on the organ donor and procurement process would result in both increased organ donor referrals and organs procured. METHODS: A retrospective review of the performance of an urban teaching ED in identifying and referring potential organ donor candidates was performed. Subsequently an intensive educational campaign of all ED staff, in conjunction with the Regional Organ Procurement Agency of Southern California (ROPA), was initiated. Physicians and nurses were educated about the procurement process, and a ROPA representative was on call 24 hours a day to assist in this process. The need for aggressive resuscitation and vital sign maintenance in potential donors as a strategy to promote organ recovery was emphasized. Reeducation by ROPA occurred every 2 to 3 months. The identification and referral rates were then retrospectively reviewed to evaluate any improvement. RESULTS: In 1994 the initial referral rate of potential organ donors from the ED was 30% (3 of 10) resulting in no organs procured. After the intervention the referral rate increased to 100% (25 of 25) in 1995 (P < .0001). The number of actual donors procured was 0 in 1994, 5 in 1995, and 9 in 1996. The increased ED referrals resulted in 14 and 32 organs procured in 1995 and 1996, respectively. CONCLUSION: Emergency physicians are in a unique position as first caregivers to interact with both potential donors and their families. With intensive education of ED staff, proper identification and referral, as well as timely intervention by organ procurement representatives, the consent and donation rate of organs for transplantation can be increased and maintained.     

A novel interferon-inducible gene expressed during myeloid differentiation

As our knowledge of the interactions of the immune, nervous and endocrine systems progresses, complex links with the origin and course of psychopathology in childhood are revealed. In this article the neuroimmunological literature on autism is reviewed. Relevant aspects of immune functioning and the neuroendocrine-immune network are described. We present the immunological findings in autistic patients within two related conceptual frameworks: a viral and an autoimmune hypothesis. Interpretation of data is hampered by conceptual and methodological differences between studies. Both the clinical significance of the immune changes and the causal connection between immune changes and psychopathological phenomena in autism remain to be elucidated. Recommendations for further research are given.     

A novel stage-specific differentiation antigen is expressed on mouse testicular germ cells during early meiotic prophase

A murine cell surface antigen exhibiting stage-specific expression during spermatogenesis was detected with two monoclonal antibodies (mAbs), designated BC7 and CA12. In mouse testis, these mAbs recognized a small population of cells located near the periphery of seminiferous tubules at stages XII and I-VI, and these spermatogenic cells were identified as zygotene and early pachytene spermatocytes. Expression of the antigens was transient and was not detected in germ cells at more advanced stages of spermatogenesis such as late pachytene spermatocytes and round spermatids. Immunoprecipitation and immunoblotting studies showed that both mAbs CA12 and BC7 reacted with the same antigenic molecule, which had an estimated molecular mass of 95 kDa. CA12/BC7 antigen, detected in plasma membrane fraction, was a glycoprotein with sialic acid residues and had affinity with WGA lectin. Furthermore, intraperitoneal injection of mAb BC7 caused an apparent spermatogenic disturbance in prepubertal mice. These results suggested that CA12/BC7 antigen, a novel cell surface glycoprotein, is an essential molecule that plays an important role during early meiotic prophase of spermatogenesis.     

Math5 encodes a murine basic helix-loop-helix transcription factor expressed during early stages of retinal neurogenesis

We have identified Math5, a mouse basic helix-loop-helix (bHLH) gene that is closely related to Drosophila atonal and Xenopus Xath5 and is largely restricted to the developing eye. Math5 retinal expression precedes differentiation of the first neurons and persists within progenitor cells until after birth. To position Math5 in a hierarchy of retinal development, we compared Math5 and Hes1 expression in wild-type and Pax6-deficient (Sey) embryos. Math5 expression is downregulated in Sey/+ eyes and abolished in Sey/Sey eye rudiments, whereas the bHLH gene Hes1 is upregulated in a similar dose-dependent manner. These results link Pax6 to the process of retinal neurogenesis and provide the first molecular correlate for the dosage-sensitivity of the Pax6 phenotype. During retinogenesis, Math5 is expressed significantly before NeuroD, Ngn2 or Mash1. To test whether these bHLH genes influence the fates of distinct classes of retinal neurons, we ectopically expressed Math5 and Mash1 in Xenopus retinal progenitors. Unexpectedly, lipofection of either mouse gene into the frog retina caused an increase in differentiated bipolar cells. Directed expression of Math5, but not Xath5, in Xenopus blastomeres produced an expanded retinal phenotype. We propose that Math5 acts as a proneural gene, but has properties different from its most closely related vertebrate family member, Xath5.     

Fuel constituent redistribution during the early stages of U-Pu-Zr irradiation

Irradiation and fission-related phenomena in metallic fuels based on the U-Pu-Zr system result in fuel restructuring in the forms of fuel swelling (Xe/Kr bubble growth) and constituent redistribution. An experiment designed to analyze the early development of these phenomena and the correlative behavior between them has recently been completed. Fuel porosity development was traced carefully as a function of fuel burnup. The results indicated that the porosity distributions would lead to significant changes in fuel operating temperature. Concurrent observations concerning composition redistribution indicated that the porosity development preceded significant constituent redistribution. The zirconium redistribution had been theorized to be related to the position of phase boundaries at specific locations within the thermal gradients existing in the fuel. The restructuring phenomena were analyzed in terms of how they may affect the existence of specific phases and, therefore, atomic migration. This paper is based on a presentation made in the symposium “Irradiation-Enhanced Materials Science and Engineering” presented as part of the ASM INTERNATIONAL 75th Anniversary celebration at the 1988 World Materials Congress in Chicago, IL, September 25-29, 1988, under the auspices of the Nuclear Materials Committee of TMS-AIME and ASM-MSD.     

Heat transfer and microstructure during the early stages of metal solidification

Transient heat transfer in the early stages of solidification of an alloy on a water-cooled chill and the consequent evolution of microstructure, quantified in terms of secondary dendrite arm spacing (SDAS), have been studied. Based on dip tests of the chill, instrumented with thermocouples, into Al-Si alloys, the influence of process variables such as mold surface roughness, mold material, metal superheat, alloy composition, and lubricant on heat transfer and cast structure has been determined. The heat flux between the solidifying metal and substrate, computed from measurements of transient temperature in the chill by the inverse heat-transfer technique, ranged from low values of 0.3 to 0.4 MW/m² to peak values of 0.95 to 2.0 MW/m². A onedimensional, implicit, finite-difference model was applied to compute heat-transfer coefficients, which ranged from 0.45 to 4.0 kW/m² °C, and local cooling rates of 10 °C/s to 100 °C/s near the chill surface, as well as growth of the solidifying shell. Near the chill surface, the SDAS varied from 12 to 22 (μm while at 20 mm from the chill, values of up to 80/smm were measured. Although the SDAS depended on the cooling rate and local solidification time, it was also found to be a direct function of the heat-transfer coefficient at distances very near to the casting/chill interface. A three-stage empirical heat-flux model based on the thermophysical properties of the mold and casting has been proposed for the simulation of the mold/casting boundary condition during solidification. The applicability of the various models proposed in the literature relating the SDAS to heat-transfer parameters has been evaluated and the extension of these models to continuous casting processes pursued.     

Isolation of a gene expressed during early embryogenesis from the region of 22q11 commonly deleted in DiGeorge syndrome

DiGeorge syndrome (DGS) is one of several syndromes associated with deletions within the proximal long-arm of chromosome 22. The region of chromosome 22q11 responsible for the haploinsufficiency syndromes (the DiGeorge Critical Region or DGCR) has been mapped using RFLPs, quantitative Southern blotting and FISH. Similar deletions are seen in the velo-cardio-facial syndrome (VCFS) and familial congenital heart defects. It is not known whether the phenotypic spectrum is the result of the hemizygosity of one gene or whether it is a consequence of contiguous genes being deleted. However, the majority of patients have a large (> = 2Mb deletion). In this paper we report the isolation of a gene, lab name T10, encoding a serine/threonine rich protein of unknown function which maps to the commonly deleted region of chromosome 22q11. Studies in the mouse indicate that it maps to MMU16 and is expressed during early embryogenesis. Although not mapping within the shortest region of overlap for DGS/VCFS, and therefore not the major gene involved in DGS, the expression pattern suggests that this gene may be involved in modifying the haploinsufficient phenotype of hemizygous patients.     

A high-resolution linkage map of the citrus tristeza virus resistance gene region in Poncirus trifoliata (L.) Raf

Resistance to citrus tristeza virus (CTV) was evaluated in 554 progeny of 10 populations derived from Poncirus trifoliata. A dominant gene (Ctv) controlled CTV resistance in P. trifoliata. Twenty-one dominant PCR-based DNA markers were identified as linked to Ctv by bulked segregant analysis. Of the 11 closest markers to Ctv, only 2 segregated in all populations. Ten of these markers were cloned and sequenced, and codominant RFLP markers were developed. Seven RFLP markers were then evaluated in 10 populations. Marker orders were consistent in all linkage maps based on data of single populations or on combined data of populations with similar segregation patterns. In a consensus map, the six closest marker loci spanned 5.3 cM of the Ctv region. Z16 cosegregated with Ctv. C19 and AD08 flanked Ctv at distances of 0.5 and 0.8 cM, respectively. These 3 markers were present as single copies in the Poncirus genome, and could be used directly for bacterial artificial chromosome library screening to initiate a walk toward Ctv. BLAST searches of the GenBank database revealed high sequence similarities between 2 markers and known plant disease resistance genes, indicating that a resistance gene cluster exists in the Ctv region in P. trifoliata.     

High resolution RBA-banding comparison between early prometaphase chromosomes of cattle (Bos taurus L.) and goat (Capra hircus L.) at 700 band level

High resolution RBA-banded early prometaphase chromosomes of cattle (Bos taurus L.) and goat (Capra hircus L.), from thymidine synchronized lymphocyte cultures, are compared at a level of 700 bands per haploid genome, with the purpose of detecting the extent of banding homologies between the two species and improving the resolution level of the ISCNDA (1989) standardized RBA-banded karyotypes. The results demonstrate that, at this level of resolution, at least 10 autosomes can be fully homologized between the two species, namely chromosomes 11, 16, 17, 18, 20, 21, 22, 23, 24 and 26, whereas the remaining autosomes show variations in some regions which require further investigations on more elongated chromosomes. Such investigations should also involve the use of GTG, GBG and RBG-banding techniques. These variations concern basically the relative distance of the bands from the centromeres or telomeres, appearance of subbands, and clustering of some positive bands.     

Bodenin: a novel murine gene expressed in restricted areas of the brain

Chronic vasodilatation represents a stimulus for capillary growth associated with increased luminal shear stress. We have examined the ultrastructure of more than 2000 capillaries to establish whether the sequence of angiogenesis in response to this stimulus is similar to that described during development and under pathological circumstances. Administration of the alpha1-blocker prazosin to rats for 2 weeks led to a greater capillary length density in extensor hallucis proprius muscles without any change in capillary tortuosity: Jv(c,f)=262+/-54 compared with 350+/-17 mm-2, control compared with prazosin (P<0.002). There were obvious signs of endothelial cell (EC) activation after prazosin treatment, including an increased proportion of capillaries with rough endoplasmic reticulum, large cytoplasmic vacuoles, thickened endothelium and an irregular luminal surface. Capillaries from control muscles had a maximum of three ECs in cross section, whereas four ECs were noted in 0.8+0.5% of capillaries after 1 week (n.s.) and 2.5+/-0.9% after 2 weeks (P<0.01) of treatment. This could be due to elongation and/or migration of ECs, as cell proliferation has not been described at these time points. There was also an increase in the proportion of capillaries having a narrow, slit-like lumen (1.7+/-0. 8% of controls; 7.1+/-1.9% at 1 week; 8.8+/-2.5% at 2 weeks; P<0.02), some of which were smaller in size (less than 2 microm diameter) than in controls (3-5 microm) and/or "seamless", i.e. lacking EC junctions. These may represent newly formed vessels. Focal discontinuity of the basement membrane and abluminal EC processes were rarely seen, and capillary growth by abluminal sprouting appeared to be very infrequent (less than 0.001% of profiles). Of more importance was growth starting from the luminal side. Significantly more thin cytoplasmic processes were observed protruding into the lumen of capillaries after 1 week (47.5+/-6.2%, P<0.001) and 2 weeks of prazosin (34.2+/-5.5%, P<0.05) than in control vessels (16.7+/-3.9%). Some of these traversed the entire lumen and connected with endothelium of the opposite side, probably involving membrane fusion, resulting in the appearance of a double lumen. Individual capillaries with a complete double lumen were observed after 2 weeks' prazosin but comparatively rarely, in only four out of six muscles. These findings indicate a pattern of luminal growth which is completely different from intussusceptive growth previously described during development, and from the abluminal capillary sprouting seen under pathological circumstances.     

Development of synaptic contacts in the human brain during the early stages of embryogenesis

In vagotomized cats, after removal of the brain portion 5 mm rostral to the visual nerves crossing, the eupnoea type of respiration was preserved. Transection in the area of the visual nerves crossing was followed by a stable acceleration of respiration. Starting from the level of the posterior border of the visual nerves crossing and more caudal, successive transections of the brain entailed sharp decrease in the breathing rate, increase of the respiratory volume, and complicated changes of the lungs ventilation.     

Backfoot is a novel homeobox gene expressed in the mesenchyme of developing hind limb

Homeobox genes play important roles in pattern formation during development. Here, we report the cloning and temporal and spatial expression patterns of a novel homeobox gene Backfoot (BFT for the human gene, and Bft for the mouse gene), whose expression reveals an early molecular distinction between forelimb and hind limb. BFT was identified as a sequence-specific DNA-binding protein. In addition to the homeodomain, it shares a carboxyl-terminal peptide motif with other paired-like homeodomain proteins. Northern hybridization analysis of RNAs from human tissues revealed that human BFT is highly expressed in adult skeletal muscle and bladder. During midgestation embryogenesis, mouse Bft is expressed in the developing hind limb buds, mandibular arches, and Rathke's pouch. The expression of Bft begins prior to the appearance of hind limb buds in mesenchyme but is never observed in forelimbs. At later stages of limb development, the expression is progressively restricted to perichondrial regions, most likely in tendons and ligaments. The timing and pattern of expression suggest that Bft plays multiple roles in hind limb patterning, branchial arch development, and pituitary development. Bft is likely identical to a mouse gene, Ptx1, that was recently isolated by Lamonerie et al. ([1996] Genes Dev. 10:1284-1295) and that has been suggested to play a role in pituitary development.     

Switch in rod opsin gene expression in the European eel, Anguilla anguilla (L.)

The rod photoreceptors of the European eel, Anguilla anguilla (L.), alter their wavelength of maximum sensitivity (lambda max) from c.a. 523 nm to c.a. 482 nm at maturation, a switch involving the synthesis of a new visual pigment protein (opsin) that is inserted into the outer segments of existing rods. We artificially induced the switch in rod opsin production by the administration of hormones, and monitored the switch at the level of mRNA accumulation using radiolabelled oligonuleotides that hybridized differently to the two forms of eel rod opsin. The production of the deep-sea form of rod opsin was detected 6 h after the first hormone injection, and the switch in rod opsin expression was complete within four weeks, at which time only the mRNA for the deep-sea opsin was detectable in the retinal cells. It is suggested that this system could be used as a tractable model for studying the regulatory control of opsin gene expression.