1-甲基环丙烯对猕猴桃贮藏品质和蛋白质组分的影响

【目的】研究了室温贮藏条件下1-甲基环丙烯(1-MCP)对猕猴桃果实呼吸、乙烯释放、贮藏品质和蛋白质组分变化的影响,为研究1-MCP在猕猴桃商业贮藏中的应用及1-MCP的作用机理提供理论依据。【方法】以‘秦美’和‘海沃德’猕猴桃为试材,研究了1-MCP在室温((20±1)℃)贮藏条件下对果实呼吸速率、乙烯释放速率、果实硬度、可滴定酸含量、可溶性固形物含量及可溶性总蛋白组分的影响。【结果】0.1μL/L 1-MCP处理能降低猕猴桃果实的呼吸速率和乙烯释放速率,抑制果实软化,延缓可滴定酸含量的下降,增加可溶性固形物含量;随着贮藏时间的延长,有特异蛋白条带出现,1-MCP处理对‘秦美’猕猴桃19.0 ku特异蛋白条带有抑制作用。【结论】1-MCP处理能延缓猕猴桃果实的衰老进程。两个猕猴桃品种相比,‘海沃德’猕猴桃产生的乙烯远低于‘秦美’猕猴桃,乙烯高峰出现也晚,果实的软化进程也较‘秦美’猕猴桃慢。

Effects of Nitrogen Fertigation Rate on Protein Components in Grains and Processing Quality of Different Wheat Varieties

[Objective] This study aimed to explore the effects of nitrogen fertigation rate on the protein components in grains and processing quality of different wheat varieties. [Method] Under the condition of higher soil fertility, different amounts of N-fertilizer were applied in the plots, and then the contents of total protein and its components, percentage of the component content to total protein content as well as the processing quality of grains of two strong-gluten wheat varieties （Linyou145 and Zhengmai9023） and two weak-gluten wheat varieties （Ningmai9 and Baofeng949） were determined. [Result] The contents of total protein and globulin, gliadin and glutenin were improved significantly with the increase of the N-fertilizer amount; but the content of albumin did not show remarkable increase; in addition, the percentage of each protein component was relative stable and did not increase significantly. Increase in the amount of N-fertilizer improved the sedimentation value, wet gluten content, loaf volume and loaf score, decreased the volume weight of grain. [Conclusion] This study provideed theoretical support for high-quality wheat production.

Agronomic Trait and Protein Component of F_2 Hybrid Originated from Intergeneric Somatic Hybridization Between Triticum aestivum and Agropyron elongatum

Protoplasts derived from common wheat (Triticum aestivum L,. cv. Jinan 177) were fused with UV-treated protoplasts of Agropyron elongatum. (Host) Nevski by PEG method, and fertile asymmetric somatic hybrid plants resembling wheat morphology were obtained. The F-2 hybrid plants could be divided into 3 types according to their morphology. Type I hybrids had high and loosely standing stalks with big spikes and grains. Type ii hybrids were dwarf and compact in shape with high tillering ability and smaller spikes. Type III hybrids were similar to type I as a whole but had more compact and erect spikes. All the F-2 hybrid lines were superior to wheat in seed protein content, although some difference existed between themselves. Protein analysis of immature embryos and flag leaves from hybrids by two-dimensional electrophoresis showed that they possessed characteristic proteins of both parents and some new proteins. There existed also some different kinds of proteins in different lines.

High-coverage proteome analysis reveals the first insight of protein modification systems in the pathogenic spirochete Leptospira interrogans

Leptospirosis is a widespread zoonotic disease caused by pathogenic spirochetes of the genus Leptospira that infects humans and a wide range of animals. By combining computational prediction and high-accuracy tandem mass spectra, we revised the genome annotation of Leptospira interrogans serovar Lai, a free-living pathogenic spirochete responsible for leptospirosis, providing substantial peptide evidence for novel genes and new gene boundaries. Subsequently, we presented a high-coverage proteome analysis of protein expression and multiple posttranslational modifications （PTMs）. Approximately 64.3% of the predicted L. interrogans proteins were cataloged by detecting 2 540 proteins. Meanwhile, a profile of multiple PTMs was concurrently established, containing in total 32 phosphorylated, 46 acetylated and 155 methylated proteins. The PTM systems in the serovar Lai show unique features. Unique eukaryotic-like features of L. interrogans protein modifications were demonstrated in both phosphorylation and arginine methylation. This systematic analysis provides not only comprehensive information of high-coverage protein expression and multiple modifications in prokaryotes but also a view suggesting that the evolutionarily primitive L. interrogans shares significant similarities in protein modification systems with eukaryotes.

Methyl-CpG binding proteins in the nervous system

Classical methyl-CpG binding proteins contain the conserved DNA binding motif methyl-cytosine binding domain(MBD), which preferentially binds to methylated CpG dinucleotides. These proteins serve as transcriptional repressors,mediating gene silencing via DNA cytosine methylation. Mutations in methyl-CpG binding protein 2 (MeCP2) have beenlinked to the human mental retardation disorder Rett syndrome, suggesting an important role for methyl-CpG bindingproteins in brain development and function. This mini-review summarizes the recent advances in studying the diversefunctions of MeCP2 as a prototype for other methyl-CpG binding proteins in the development and function of thevertebrate nervous system.

Serum Protein Capillary Electrophoretic Pattern in Camels （Camelus dromedarius）： Influence of Age and Sex

The objective of this study was to characterise serum protein capillary electrophoretic pattern in relation to the age and sex in dromedary camels. Fourteen healthy young camels （age： 3-5 months）, 12 adult male and 10 female camels （age： 5-8 years） were used. Blood samples collected from the jugular vein were used for the determination of serum proteins by capillary electrophoresis technique. Female camels had significantly （P 〈 0.05） higher serum-[Protein] of 63.7 ± 6.6 g/L （reference range = 51-74 g/L） compared to the other age groups. Adult male camels showed significantly （P 〈 0.05） higher percentage of albumin fraction （60%） compared to the other age groups. The concentrations of ul and ct2 globulin fractions were significantly （P 〈 0.05） higher mean value in young camels compared to the other groups （3.5% and 8.5%, respectively）. 13-globulin fraction was not affected significantly by the age. The concentration of y-globulin fraction （26%） in lactating camels was higher （P 〈 0.05） compared to the other age groups. Significantly （P 〈 0.05） A/G ratio was observed in young camels. Sex had no significant effect on serum protein fractions. The results obtained were compared and interpreted in the light of finding reported by other investigators in camels, humans and other animals.

The plasma membrane calcium pump in the hearing process:physiology and pathology

Mammalian cells express four different plasma membrane Ca2+ ATPases.Two of them(PMCA1 and PMCA4) are expressed ubiquitously,and are considered housekeeping isoforms.Two(PMCA2 and PMCA4) have tissue restricted distribution.They are abundantly expressed in the brain and in nervous tissue-derived cell types.The primary transcripts of all PMCAs undergo alternative splicing,generating a large number of additional isoforms.Splicing occurs at site A,in the N-terminal moiety of the pump,and at site C,within the C-terminal calmodulin binding domain:The pumps are canonical targets of calmodulin stimu-lation.The site C insertion leads to a truncation of the pump about 50 residues short of the original C-terminal.One of the pumps(PMCA2) has special properties:It displays high activity even in the absence of the natural activator calmodulin,and has a particularly complex pattern of alternative splicing at both sites A and C.A variant of the PMCA2 pump containing an insert at site A and truncated C-terminally is the resident isoform of the pump in the stereocilia of hair cells of the inner ear.It exports Ca2+to the endolymph that bathes the stereocilia less efficiently than the full length,non-inserted PMCA2 pump.The proper functioning of hair cells demands the precise maintenance of the Ca2+balance between hair cells and the endolymph. Disturbances in the balance affect the process of mechano-electrical transduction,which depends on the ability of the stereo-ciliar bundle to deflect in response to sound waves.The tip links that organize the bundle are formed by the Ca2+binding pro-tein cadherin 23 and by protocadherin 15:Disturbances of the Ca2+binding by cadherin 23 and/or of the ability of the PMCA2 variant of the stereocilia to export Ca2+to the endolymph generate hearing loss phenotypes.Such phenotypes have now been described in mice and humans.In some cases they are linked to mutations of both cadherin 23 and the PMCA2 pump,but in other cases they may be generated by mutations of particular severity in only one of the two proteins.The PMCA2 defect that leads to deafness has now been analyzed molecularly:It affects the long range,unstimulated ability of PMCA2 to export Ca2+.

Science Letters:Proteomic analysis of differentially expressed proteins in mice with concanavalin A-induced hepatitis

Objective： To find new protein biomarkers for the detection and evaluation of liver injury and to analyze the relationship between such proteins and disease progression in concanavalin A （Con A）-induced hepatitis. Methods： Twenty-five mice were randomly divided into five groups： an untreated group, a control group injected with phosphate buffered saline （PBS）, and groups with Con A-induced hepatitis evaluated at 1, 3 and 6 h. Two-dimensional gel electrophoresis （2-DE） and mass spectrometry （MS） were used to identify differences in protein expression among groups. Quantitative real-time polymerase chain reaction （qRT-PCR） was performed to verify the results. Results： In mice with Con A-induced hepatitis, expression levels of four proteins were increased： RIKEN, fructose bisphosphatase 1 （fbp1）, ketohexokinase （khk）, and Chain A of class pi glutathione S-transferase. Changes in fbpl and khk were confirmed by qRT-PCR. Conclusion： Levels of two proteins, fbp1 and khk, are clearly up-regulated in mice with Con A-induced hepatitis.

Antigenically dominant proteins within the human liver mitochondrial proteome identified by monoclonal antibodies

Analysis of the mitochondrial proteome would provide valuable insight into the function of this important organelle, which plays key roles in energy metabolism, apoptosis, free radical production, thermogenesis, and calcium signaling. It could also increase our understanding about the mechanisms that promote mitochondrial disease. To identify proteins that are antigenically dominant in human liver mitochondria, we generated >240 hybridoma cell lines from native mitochondrial proteins after cell fusion, screening, and cloning. Antibodies that recognized mitochondrial proteins were identified by screening human liver cDNA expression libraries. In this study, we identified 6 major antigens that were recognized by at least 2 different monoclonal antibodies (mAbs). The proteins that were antigenically dominant were: acetyl-Coenzyme A acyltransferase 2 (mitochondrial 3-oxoacyl-Coenzyme A thiolase), aldehyde dehydrogenase 1 family member A1, carbamoyl phosphate synthetase 1, dihydrolipoamide S-acetyltransferase (E2 component of pyruvate dehydrogenase complex), enoyl coenzyme A hydratase 1, and hydroxysteroid (11-beta) dehydrogenase 1. We also determined the subcellular localizations of these enzymes within the mitochondria using immunohistocytochemistry. We believe that these well-characterized antibodies will provide a valuable resource for the Human Liver Proteome Project (HLPP), and will make studies aimed at investigating liver mitochondrial function far easier to perform in future. Our results provide strong evidence that, (i) depletion of dominant proteins from liver mitochondrial samples is possible and, (ii) the approaches adopted in this study can be used to explore or validate protein-protein interactions in this important organelle.