Aroma precursors of cigars from different tobacco parts and origins, and their correlations with sensory characteristics.

Cigars are developing rapidly around the world, but the content characteristics of aroma precursors and their contribution to sensory perception have not been fully elucidated. In this study, 69 aroma precursors from 61 tobaccos of different parts and origins were systematically determined, and the sensory characteristics of middle leaves from different origins and their correlation with aroma precursors were evaluated. The results showed that tobacco parts mainly affected amino acid content, and contents of nicotine, oxalic acid, malic acid, isovaleric acid, cystine, glutarnine, glycine, isoleucine, glutamicacid, asparticacid, and fructose-proline were significantly changed. Tobacco origins mainly influenced the contents of amino acids, polyacids and high fatty acids, and sugar alcohols, and significantly affected the contents of myosmine, anabasine, nonanoic acid, propanetriol, mannitol, mannose, glucose, alanine, arginine, glutarnine, glutamicacid, histidine, serine, threonine, tryptophan, fructose-alanine, and fructose-asparagine. The flavor characteristics were prominent by wood aroma, and the style and quality characteristics varied greatly among different origins of middle leaves. There were 34, 21, and 22 aroma precursors with high correlations with flavor, style, and quality characteristics. This study provides support for regulating the content and coordination of aroma precursors in different tobacco parts and origins to improve sensory characteristics.

Research progress on extraction, purification, structure and biological activity of Dendrobium officinale polysaccharides.

Dendrobium officinale Kimura et Migo (D. officinale) is a traditional medicinal and food homologous plant that has been used for thousands of years in folk medicine and nutritious food. Recent studies have shown that polysaccharide is one of the main biologically active components in D. officinale. D. officinale polysaccharides possess several biological activities, such as anti-oxidant, heptatoprotective, immunomodulatory, gastrointestinal protection, hypoglycemic, and anti-tumor activities. In the past decade, polysaccharides have been isolated from D. officinale by physical and enzymatic methods and have been subjected to structural characterization and activity studies. Progress in extraction, purification, structural characterization, bioactivity, structure-activity relationship, and possible bioactivity mechanism of polysaccharides D. officinale were reviewed. In order to provide reference for the in-depth study of D. officinale polysaccharides and the application in functional food and biomedical research.

Quantitative proteomics reveals that long non-coding RNA MALAT1 interacts with DBC1 to regulate p53 acetylation.

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a broadly expressed lncRNA involved in many aspects of cellular processes. To further delineate the underlying molecular mechanism, we employed a high-throughput strategy to characterize the interacting proteins of MALAT1 by combining RNA pull-down, quantitative proteomics, bioinformatics, and experimental validation. Our approach identified 127 potential MALAT1-interacting proteins and established a highly connected MALAT1 interactome network consisting of 788 connections. Gene ontology annotation and network analysis showed that MALAT1 was highly involved in five biological processes: RNA processing; gene transcription; ribosomal proteins; protein degradation; and metabolism regulation. The interaction between MALAT1 and depleted in breast cancer 1 (DBC1) was validated using RNA pull-down and RNA immunoprecipitation. Further mechanistic studies reveal that MALAT1 binding competes with the interaction between sirtuin1 (SIRT1) and DBC1, which then releases SIRT1 and enhances its deacetylation activity. Consequently, the deacetylation of p53 reduces the transcription of a spectrum of its downstream target genes, promotes cell proliferation and inhibits cell apoptosis. Our results uncover a novel mechanism by which MALAT1 regulates the activity of p53 through the lncRNA-protein interaction.

Deciphering the protein-protein interaction network regulating hepatocellular carcinoma metastasis.

Hepatocellular carcinoma (HCC) is one of the leading causes of mortality related to cancer all over the world. To better understand the molecular mechanisms of HCC metastasis, we analyzed the proteome of three HCC cell lines with different metastasis potentials by quantitative proteomics and bioinformatics analysis. As a result, we identified 378 cellular proteins potentially associated to HCC metastasis, and constructed a highly connected protein-protein interaction (PPI) network. Functional annotation of the network uncovered prominent pathways and key roles of these proteins, suggesting that the metabolism and cytoskeleton biological processes are greatly involved with HCC metastasis. Furthermore, the integrative network analysis revealed a rich-club organization within the PPI network, indicating a hub center of connections. The rich-club nodes include several well-known cancer-related proteins, such as proto-oncogene non-receptor tyrosine kinase (SRC) and pyruvate kinase M2 (PKM2). Moreover, the differential expressions of two identified proteins, including PKM2 and actin-related protein 2/3 complex subunit 4 (ARPC4), were validated using Western blotting. These two proteins were revealed as potential prognostic markers for HCC as shown by survival rate analysis.

Identification of a novel mitochondrial interacting protein of C1QBP using subcellular fractionation coupled with CoIP-MS.

The study of protein-protein interactions is an essential process to understand the biological functions of proteins and the underlying mechanisms. Co-immunoprecipitation coupled with mass spectrometry (CoIP-MS) is one of the most extensively used high-throughput techniques to discover novel protein-protein interactions. However, the traditional CoIP process uses whole cell lysate, disrupts cellular organization, and leads to potential false positives by inducing artificial protein-protein interactions. Here, we have developed a strategy by combining subcellular fractionation with CoIP-MS to study the interacting proteins of the complement component 1, q subcomponent binding protein (C1QBP) in the mitochondria. Using this method, a novel C1QBP interacting protein, dihydrolipoyllysine-residue acetyltransferase component of pyruvate dehydrogenase complex, mitochondrial (DLAT) was identified and validated. Furthermore, the activity of the pyruvate dehydrogenase (PDH) was found to be affected by the expression level of C1QBP. These results provide novel insights regarding the mitochondrial function of C1QBP in the regulation of cellular energy metabolism. This method could also be used to analyze the subcellular protein-protein interactions for other proteins of interest.

Quantitative proteomic analysis for high-throughput screening of differential glycoproteins in hepatocellular carcinoma serum.

OBJECTIVE: Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths. Novel serum biomarkers are required to increase the sensitivity and specificity of serum screening for early HCC diagnosis. This study employed a quantitative proteomic strategy to analyze the differential expression of serum glycoproteins between HCC and normal control serum samples. METHODS: Lectin affinity chromatography (LAC) was used to enrich glycoproteins from the serum samples. Quantitative mass spectrometric analysis combined with stable isotope dimethyl labeling and 2D liquid chromatography (LC) separations were performed to examine the differential levels of the detected proteins between HCC and control serum samples. Western blot was used to analyze the differential expression levels of the three serum proteins. RESULTS: A total of 2,280 protein groups were identified in the serum samples from HCC patients by using the 2D LC-MS/MS method. Up to 36 proteins were up-regulated in the HCC serum, whereas 19 proteins were down-regulated. Three differential glycoproteins, namely, fibrinogen gamma chain (FGG), FOS-like antigen 2 (FOSL2), and α-1,6-mannosylglycoprotein 6-ß-N-acetylglucosaminyltransferase B (MGAT5B) were validated by Western blot. All these three proteins were up-regulated in the HCC serum samples. CONCLUSION: A quantitative glycoproteomic method was established and proven useful to determine potential novel biomarkers for HCC.

[Effects of low temperature and weak light on the functions of photosystem in Prunus armeniaca L. leaves in solar greenhouse].

In this paper, the net photosynthetic rate (Pn), actual photochemical efficiency of PS II (PhiPSII), photochemical quenching (qp), and maximal photochemical efficiency of PS II in light (Fv'/Fm') of apricot (Prunus armeniaca) leaves in solar greenhouse were measured, and the effects of low temperature (7 degrees C) and weak light (200 micromol x m(-2) x s(-1) PFD) on the photoinhibition of PS I and PS II were investigated. The results showed that the optimal temperature for the photosynthesis of apricot leaves was around 25 degrees C, and the photosynthetic capacity was reduced greatly by the low temperature and weak light, inducing a markedly increased excitation press (1-qp) and in turn, resulting in photoinhibition. The functions of both PS I and PS II were damaged by the low temperature and weak light. Comparing with those only subjected to low temperature, the leaves subjected to both low temperature and weak light had a decreased activity of PS I, with a decrement of 28.26% within 2 h, but their maximal photochemical effeciency of PS II (Fv/Fm) had little change in the same period, suggesting that under low temperature and weak light, PS I was more suffered from photoinhibition than PS II.

[Physiological function of arginine and its metabolites in plants].

L-arginine is an important and unique amino acid in plants. It serves not only as an important nitrogen reserve and recycling, but also as a precursor of the biosynthesis of polyamines, nitric oxide and so on. Polyamines and nitric oxide are important messengers involved in almost all physiological and biochemical processes, growth & development, and adaptation of plants to stress. Arginine decarboxylase, arginase and nitric oxide synthase are the key enzymes in L-arginine catabolism, in which polyamines are formed through ADC or arginase-ODC pathway while nitric oxide is formed through the NOS pathway. The relative activity of these three enzymes can control the direction of arginine metabolism. Arginine content keeps higher level in roots during overwinter period. The arginine metabolism plays important role in perception and adaptation of plant to environmental disturbances.