不同成熟采收期对清水白桃果实达到完熟时品质的影响(英文)

以软溶质水蜜桃清水白桃为试材,分别在树上完熟的前6、4和2d采样,贮藏于25℃,相对湿度90%的环境条件下至完熟,与树上完熟果实相比较,调查了果实的生理变化、色泽和果汁品质性状,并对完熟果实进行了风味评定。结果表明,贮藏期间的果实乙烯释放量以完熟前2d采收的果实增加最快并在果实完熟时达到最大,树上完熟的果实乙烯释放量最少。树上完熟前6d采收的果实,果皮亮度、果汁的蔗糖含量、“果香型”内酯类物质含量均低于后3次采收的果实,其中以树上完熟前2d采收的果实为最高。相反滴定酸、柠檬酸、天冬酰胺和“清香型”香气物质含量以树上完熟前6d采收的果实最高。完熟果实的风味评定也显示了树上完熟前2d采收的果实综合评价最高,早期采收的果实即使贮藏后达到完熟果肉硬度,甜度和香味少、酸味重。另外,树上完熟的果实肉质粗,酸度低,有怪香味,综合评价不高。     

Plants tolerant of high boron levels

Reduced crop productivity due to soils containing toxic levels of boron (B) is a worldwide problem in food production. It is estimated that up to 17% of the barley yield losses in southern Australia are caused by B toxicity. We found that the expression of AtBOR4, an Arabidopsis paralog of BOR1, the first identified boron transporter gene, generates plants that are tolerant of high B levels. BOR4 is a polarly localized borate exporter that enhances B efflux from roots. The present study is a foundation for the improvement of crop productivity in soils containing excess B, which are distributed in arid areas of the world.     

Bacterial degradation of antibiotic residues in marine fish farm sediments of Uranouchi Bay and phylogenetic analysis of antibiotic-degrading bacteria using 16S rDNA sequences

ABSTRACT:   Antibiotic residues in marine sediments of fish farms negatively influence microbial ecologic systems. The microbial degradation of antibiotic residues was experimentally examined in the marine sediments of Uranouchi Bay, to which one of five antibiotics was added. After incubation reducing physical factors, ampicillin, doxycycline, oxytetracycline, and thiamphenicol were significantly degraded, while josamycin maintained most of the initial amounts. The isolates resistant to ampicillin, josamycin, oxytetracycline, or thiamphenicol degraded each antibiotic in wide ranges of degrees, whereas the isolates degrading doxycycline were not obtained. Microbial degradation may contribute to the disappearance of ampicillin, doxycycline, oxytetracycline, and thiamphenicol in the fish farm. In contrast, the disappearance of josamycin would depend on physical factors, but the bacteria degrading josamycin at least exist in the marine sediments. Phylogenetic analysis using 16S rDNA sequences demonstrated that the antibiotic-resistant isolates formed several clusters in the Gram-positive bacterial group, the Flavobacterium–Cytophaga–Bacteroides group, and the proteobacteria subdivisions. The antibiotic-resistant bacterial population would be composed of various species including ubiquitous coastal bacterial groups. Several species of antibiotic resistant bacteria show antibiotic degradation activities, and appear to contribute to the disappearance of antibiotics in Uranouchi Bay.     

Normal DNA methylation status in sperm from a somatic cell cloned bull and their fertilized embryos

Epigenetic reprogramming confers totipotency even during somatic cell nuclear transfer (SCNT), which has been used to clone various animal species. However, as even apparently healthy cloned animals sometimes have aberrant epigenetic status, the harmful effects of these defects could be passed onto their offspring. This is one of the biggest obstacles for the application of cloned animals for livestock production. Here, we investigated the DNA methylation status of four developmentally regulated genes (PEG3, XIST, OCT4, and NANOG) in sperms from a cloned and a non‐cloned bull, and blastocysts obtained by in vitro fertilization using those sperms and SCNT. We found no differences in the methylation status of the above genes between cloned and non‐cloned bull sperms. Moreover, the methylation status was also similar in blastocysts obtained with cloned and non‐cloned bull sperms. In contrast, the methylation status was compromised in the SCNT blastocysts. These results indicate that sperm from cloned bulls would be adequately reprogrammed during spermatogenesis and, thus, could be used to produce epigenetically normal embryos. This study highlights the normality of cloned bull offspring and supports the application of cloned cattle for calf production.     

Carbon nanotube enhanced label-free immunosensor for amperometric determination of oocyte maturation-inducing hormone in fish

Maintaining high-quality fish eggs stably and efficiently is important for aquaculture. We developed a label-free immunosensor system for measuring 17,20β-dihydroxy-4-pregnen-3-one (DHP). DHP is suddenly secreted before ovulation as a maturation-inducing hormone in fish, and therefore, DHP levels are an indicator for predicting ovulation. The method is based on immunologic reactions and amperometric measurement using cyclic voltammetry (CV). For biomolecular immobilization on the surface of sensing electrode, Au electrode, we used self-assembled monolayers of thiol-containing compounds to fix anti-DHP immunoglobulin. In addition, we used a single-walled carbon nanotube to improve sensitivity. Using this electrode, we were able to determine the CV signal change caused by the antigen–antibody complex. The proposed immunosensor system showed a linear correlation (correlation coefficient: 0.9827) between the anodic peak current of the CV and the DHP level in range from 15.6 to 50,000 pg ml^?1. The sensor system was then applied to monitor DHP of goldfish (Carassius auratus). Blood plasma of fish was collected every 3 h after administering a DHP inducer. In the measurement, the anodic peak current of the CV showed distinct changes depending on DHP levels in the blood plasma. A good relationship was observed between DHP levels determined by our proposed system and the conventional method (correlation coefficient: 0.9351).     

Ultra highly sensitive method for detecting Flavobacterium psychrophilum using high‐gradient immunomagnetic separation with a polymerase chain reaction

We attempted to develop an ultrahigh sensitive method for detecting Flavobacterium psychrophilum using high‐gradient immunomagnetic separation (HGIMS) with a polymerase chain reaction (PCR). HGIMS is a magnetic separation method in which the magnetic force is strengthened by introducing a magnetic gradient between the magnetic filter and nearby column. Because immunomagnetic beads specifically react with target cells, target cells are collected efficiently. Accumulated beads are released from the filter by removing the external magnetic force. After concentrating the samples using the HGIMS system, DNA was extracted from the samples, and PCR was applied to detect F. psychrophilum. Our primers did not react with reference bacteria and reacted specifically with F. psychrophilum. The detection sensitivity using the HGIMS system was higher than that of the method without the HGIMS system, and the total assay time, including sample preparation, was <3.5 h. PCR products of the expected size were obtained from samples of concentrated 4 × 10^?1 to 4 × 10³ cfu mL^?1F. psychrophilum more than 80% of the time using the HGIMS system. Furthermore, our proposed method could be useful for the specific detection of F. psychrophilum from actual samples. Our proposed method is suitable for the highly sensitive detection of F. psychrophilum.     

Effect of low molecular weight lignin fragments including oxalic acid in alkaline-oxygen stage waste liquor on Al toxicity

Our previous study indicated the existence of some low molecular weight contaminants in separated fractions (F1 to F4) of alkaline-oxygen stage waste liquor by spectroscopic analysis. In the present study, the quantities of these compounds were determined by capillary electropheresis (CE). Substantial amounts of oxalate and acetate were found in F3. The complexes between Al and oxalate as well as F3 were characterized by ²⁷Al-nuclear magnetic resonance (NMR) spectroscopy, and the spectra of Al-oxalate complexes demonstrated the ability of oxalate to chelate Al and to produce different forms of complexes at varied molar ratios. Plant growth experiments in the presence of Al-oxalate complexes suggested that at a proper range, oxalate has a favorable effect on the detoxification of Al toxicity. It can be assumed that oxalate in F3 also plays an important role in the efficiency of removing Al toxicity. ²⁷Al-NMR was proved to be a useful method for the study of complexes between Al and organic compounds without disturbing their equilibrium conditions.     

Termite resistance and wood-penetrability of chemically modified tannin and tannin-copper complexes as wood preservatives

We examined the ability of chemically modified tannin and tannin-copper complexes to penetrate wood and the ability of the treated wood to resist termites. Only the tannin-treated wood retained the agents after treatment. Wood with untreated mimosa tannin (MT) retained the least amount, followed by wood with resorcinolated tannin (RMT) and that with catecholated tannin (CMT). When RMT or CMT was mixed with ammonia-copper, the wood retained twice as much of these solutions as the MT -ammonia-copper solution. The degree of retention of RMT-NH₃-Cu and CMT-NH₃-Cu ranged from 268 to 326kg/m³. The solutions penetrated 2–13 mm from the tangential sections of the logs. We also measured the termite resistance conferred by these solutions. Most of the tannin-NH₃-Cu solutions showed contact lethality for termites in the contact toxicity test. However, the termites were fed cellulose treated with those solutions and most survived the oral toxicity test (14 days). Moreover, these solutions reduced the amount of damage to the wood by termites. However, the mortality rate of the termites during the eating-damage test (>21 days) did not reach 100% for any of the solutions except for RMT. As a result of the field stake test with the same log's used for the penetrability test, the mass loss of wood treated with RMT or CMT alone or with RMT + NH₃ + CuCl₂, was about one-third to one-half that of the controls. Because these solutions have good wood penetrability and good termite resistance, they have potential use as low-toxicity wood preservatives.     

Prominent expression of spinocerebellar ataxia type-1 (SCA1) gene encoding ataxin-1 in LH-producing cells, LbetaT2

The LH-producing cell line, LbetaT2, and non LH-producing cell line, alphaT3-1 cells, established from a pituitary tumor, were employed for cDNA subtraction cloning to identify genes with expression unique to LH producing cells. Several cDNAs that code for known as well as for many unidentified clones were discovered. Most clones were the spinocerebellar ataxia type-1 (SCA1) gene encoding ataxin-1, the abnormality of which causes neurodegeneration and loss of cerebellar Purkinje cells. We examined whether the expression of SCA1 gene in LbetaT2 cells is related to hormone production. We also compared the expression of SCA1 with that in various other pituitary tumor derived cell lines, and confirmed the prominent expression of SCA1 in LbetaT2 cells. The effect of gonadal factor(s) for SCA1 gene expression was examined. The expression level in female rats was low and did not change during the estrus cycle, but increased significantly after ovariectomy and did not return to the normal level under low and high doses of estrogen. In the male pituitary SCA1 gene expression increased markedly after castration and was not decreased by estrogen or testosterone. The Ontogeny of SCA1 gene expression was investigated in porcine fetal and postnatal pituitaries and revealed biphasic and sexually dimorphic expression. Transient expression of SCA1 gene was observed at fetal day 50 and 65 in males and day 40 in females, followed by a decline and increased expression before birth in both genders. Thus the expression of SCA1 gene is prominent in LH-producing cells and is not under direct control of gonadal factor(s) in both genders. In addition to the variable expression of SCA1 gene during the fetus period, the present results provide a novel aspect to the understanding of Boucher-Neuhauser syndrome (Ataxia Hypogonadism Choroidal Dystrophy).