scholarly journals Interactions of Cloud Proteins, Pectins and Pectinesterases in Flocculation of Citrus Cloud

2002 ◽  
Author(s):  
Ilan Shomer ◽  
Louise Wicker ◽  
Uzi Merin ◽  
William L. Kerr
Keyword(s):  
Structural Changes ◽  
Specific Interaction ◽  
Light And Electron Microscopy ◽  
Citrus Fruit ◽  
Heat Inactivation ◽  
Complex Process ◽  
Neutral Sugars ◽  
Important Quality

The overall objective was to understand the cloud flocculation of citrus juice by characterization of the interactions between proteins and pectins, and to determine the role of PE isozymes in catalyzing this phenomenon. Specific objectives were to: 1. identify/characterize cloud-proteins in relation to their coagulable properties and affinity to pectins; 2. to determine structural changes of PME and other proteins induced by cation/pectin interactions; 3. localize cloud proteins, PME and bound protein/pectates in unheated and pasteurized juices; 4. to create "sensitized" pectins and determine their effect on clarification. The original objectives were not changed but the methods and approach were modified due to specific research requirements. Two i postulates were: 1. there is a specific interaction of cloud proteins with de-esterified regions of ! pectin and this contributes to cloud loss; 2. isozymes of pectin-methyl-esterase (PME) vary in efficiency to create sensitized pectins. The appearance of citrus fruit juice is an important quality factor and is determined by the color and turbidity that .are conferred by the suspended particles, i.e., by the cloud and its homogeneity. Under some circumstances the cloud tend to flocculate and the juice clarifies. The accepted approach to explain the clarification is based on pectin demethoxylation by PME that promotes formation of Ca-pectate. Therefore, the juice includes immediate heat-inactivation upon ~ squeezing. Protein coagulation also promotes cloud instability of citrus fruit extracts. However, the clarification mechanism is not fully understood. Information accumulated from several laboratories indicates that clarification is a more complex process than can be explained by a single mechanism. The increasing trend to consume natural-fresh juice emphasizing the importance of the knowledge to assure homogeneity of fresh juice. The research included complementary directions: Conditions that induce cloud-instability of natural- juice [IL]. Evaluate purification schemes of protein [USA]. Identifications of proteins, pectin and neutral sugars ([IL]; Structure of the cloud components using light and electron microscopy and immuno-labeling of PME, high-methoxyl-pectin (HMP) and low-methoxyl-pectin (LMP); Molecular weight of calcium sensitized pectins [US]; Evaluation of the products of PME activity [US]. Fractions and size distribution and cloud components [IL-US]. The optimal pH activity of PME is 7 and the flocculation pH of the cloud is 3-4. Thus, the c roles of PME, proteins and pectins in the cloud instability, were studied in pH ranges of 2- 7. The experiments led to establish firstly repeatable simulate conditions for cloud instability [IL]. Thermostable PME (TS-PE) known to induce cloud instability, but also thermolabile forms of PME (TL-PE) caused clarification, most likely due to the formation and dissolution of inactive :. PE-pectin complexes and displacement of a protective colloid from the cloud surface [US]. Furthermore, elimination of non-PME protein increases TS-PE activity, indicating that non-PME proteins moderate PME activity [US]. Other experiments Concomitantly with the study of the PME activity but promotes the association of cloud-proteins to pectin. Adjusting of the juice pH to f 7 retains the cloud stability and re-adjusting of the pH to 40% DE reacts to immuno-labeling in the cloud fragments, whereas

scholarly journals USG and CT scan evaluation of patients of acute and chronic pancreatitis- a cross-sectional, comparative study

2017 ◽  
Vol 5 (8) ◽  
pp. 3713 ◽  
Author(s):  
Aastha Bhatt ◽  
Awdhut Tiparse ◽  
Arpita Patel ◽  
Birwa Gandhi
Keyword(s):  
Ct Scan ◽  
Structural Changes ◽  
Radiation Hazard ◽  
Government Medical College ◽  
Detailed Characterization ◽  
Cross Sectional ◽  
Medical College ◽  
Adjacent Structures

Background: Pancreatitis is a condition of inflammation of pancreas with high rate of morbidity and mortality. USG provides the initial radiological assessment of the organ, clue of the extent of involvement and an opportunity to evaluate other abdominal organs. CT scan provides a cross-sectional anatomy of the organ, its internal structure, focal or diffuse involvement and involvement of adjacent structures. This study is done to evaluate the role of USG and CT scan in patients of pancreatitis admitted to Sir Takhtsinhji hospital, government medical college, Bhavnagar, Gujarat, India. Aim was to understand the role of CT and USG in determination of diagnosis of pancreatitis and to highlight and evaluate the cases in which USG failed to diagnose the cases which were helped through by CT.Methods: This study was done in department of radio diagnosis at Sir Takhtsinhji hospital, government medical college, Bhavnagar, Gujarat, India, over a period of one year from June 2015 to June 2016. Each patient was studied taking into consideration relevant clinical and laboratory factors. USG of patients was done using My Lab 40 or My Lab 20 plus machine. CT scan was done using GE 16 Slice CT scan machine.Results: Ultrasound by non-invasiveness, lack of radiation hazard and by ability to demonstrate structural changes in organ is first investigation of choice in pancreatitis. However, USG fails imaging in conditions with excess of bowel gas or fatty patient. It lacks in detailed characterization of the inflammatory process and does not delineate extent of necrosis of the gland. CT is superior to ultrasound for precise detection of size, parenchyma, MPD, calcification, pseudocyst, ascites, pleural effusion, necrosis and peri pancreatic region and hence helps to determine exact extent of inflammation of the organ, multi-system involvement and prognosis.Conclusions: Ultrasound by non-invasiveness, easy availability, cost parameters, lack of radiation hazard and by ability to demonstrate structural changes in organ is first investigation of choice in pancreatitis. However, ultrasonography lacks in detailed characterization of the extent of involvement of the organ and adjacent structures. CT is superior to ultrasound for precise detection and extension of the pancreatitis and it has better sensitivity and specificity than ultrasonography. 

scholarly journals Human testis-expressed (TEX) genes: a review focused on spermatogenesis and male fertility

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Hela Bellil ◽  
Farah Ghieh ◽  
Emeline Hermel ◽  
Béatrice Mandon-Pepin ◽  
François Vialard
Keyword(s):  
Current Knowledge ◽  
Gene Mutations ◽  
Subtractive Hybridization ◽  
Human Testis ◽  
Rna Seq ◽  
Reproductive Process ◽  
Complex Process ◽  
Expression Atlas

AbstractSpermatogenesis is a complex process regulated by a multitude of genes. The identification and characterization of male-germ-cell-specific genes is crucial to understanding the mechanisms through which the cells develop. The term “TEX gene” was coined by Wang et al. (Nat Genet. 2001; 27: 422–6) after they used cDNA suppression subtractive hybridization (SSH) to identify new transcripts that were present only in purified mouse spermatogonia. TEX (Testis expressed) orthologues have been found in other vertebrates (mammals, birds, and reptiles), invertebrates, and yeasts. To date, 69 TEX genes have been described in different species and different tissues. To evaluate the expression of each TEX/tex gene, we compiled data from 7 different RNA-Seq mRNA databases in humans, and 4 in the mouse according to the expression atlas database.Various studies have highlighted a role for many of these genes in spermatogenesis. Here, we review current knowledge on the TEX genes and their roles in spermatogenesis and fertilization in humans and, comparatively, in other species (notably the mouse). As expected, TEX genes appear to have a major role in reproduction in general and in spermatogenesis in humans but also in all mammals such as the mouse. Most of them are expressed specifically or predominantly in the testis. As most of the TEX genes are highly conserved in mammals, defects in the male (gene mutations in humans and gene-null mice) lead to infertility. In the future, cumulative data on the human TEX genes’ physiological functions and pathophysiological dysfunctions should become available and is likely to confirm the essential role of this family in the reproductive process. Thirteen TEX genes are now referenced in the OMIM database, and 3 have been linked to a specific phenotype. TEX11 (on Xq13.1) is currently the gene most frequently reported as being associated with azoospermia.

Analysis of Composites for Best Designs of Refractive Solar Concentrators

2014 ◽  
Vol 887-888 ◽  
pp. 57-61
Author(s):  
José Ignacio Pérez Calero
Keyword(s):  
Finite Elements ◽  
Composite Laminates ◽  
Solar Concentrators ◽  
Complex Process

This Paper studies the important role of the Composites, in the complex process of designing Solar Refractive Concentrators, that would be unthinkable and unrealizable without their employment, when having necessary the technical characteristics that they make them viable. It contributes, also, the methodologies followed for the accomplishment of optimal prototypes, by means of Numeric Methods of simulation (Finite Elements), experimental on models and of characterization of composite laminates.

scholarly journals Characterization of a caffeoyl-CoA O-methyltransferase-like enzyme involved in biosynthesis of polymethoxylated flavones in Citrus reticulata

2020 ◽  
Vol 71 (10) ◽  
pp. 3066-3079 ◽  
Author(s):  
Xiaojuan Liu ◽  
Chenning Zhao ◽  
Qin Gong ◽  
Yue Wang ◽  
Jinping Cao ◽  
...  
Keyword(s):  
Citrus Fruit ◽  
Citrus Reticulata ◽  
Fruit Peel ◽  
Polymethoxylated Flavones ◽  
Transient Overexpression ◽  
Highly Correlated

Abstract Polymethoxylated flavones (PMFs), which accumulate exclusively in fruit peel of citrus, play important physiological and pharmacological roles but the genetic basis for the methylation of flavonoids has not been fully elucidated in citrus. Here we characterize a caffeoyl-CoA O-methyltransferase-like enzyme, designated CrOMT1. The expression pattern of CrOMT1 was highly correlated with the concentration of the three major PMFs in two different citrus fruit tissues during fruit maturation. Exposure of fruit to UV-B radiation sharply increased the level of CrOMT1 transcripts and also led to the accumulation of three PMFs. The potential role of CrOMT1 was studied by testing the catalytic activity of recombinant CrOMT1 with numerous possible substrates in vitro. The enzyme could most efficiently methylate flavones with neighboring hydroxy moieties, with high catalytic efficiencies found with 6-OH- and 8-OH-containing compounds, preferences that correspond precisely with the essential methylation sites involved in the synthesis of the three naturally occurring PMFs in Citrus reticulata. This indicates that CrOMT1 is capable of in vitro methylation reactions required to synthesize PMFs in vivo. Furthermore, transient overexpression of CrOMT1 increased levels of the three major PMFs in fruit, indicating that CrOMT1 is likely to play an essential role in the biosynthesis of PMFs in citrus.

scholarly journals Characterization of the OFP Gene Family and its Putative Involvement of Tuberous Root Shape in Radish

2020 ◽  
Vol 21 (4) ◽  
pp. 1293 ◽  
Author(s):  
Yanping Wang ◽  
Qingbiao Wang ◽  
Wei Hao ◽  
Honghe Sun ◽  
Li Zhang
Keyword(s):  
Root Elongation ◽  
Root Formation ◽  
Expression Patterns ◽  
Tuberous Root ◽  
Quality Trait ◽  
Functional Protein ◽  
Specific Proteins ◽  
Important Quality

The shape of the tuberous root, a very important quality trait, varies dramatically among radish cultivars. Ovate family proteins (OFPs) are plant-specific proteins that regulate multiple aspects of plant growth and development. To investigate the possible role of OFPs in radish tuberous root formation, 35 putative RsOFPs were identified from radish, and their expression patterns were detected during tuberous root development in six different radish cultivars. Phylogenetically, RsOFP2.3 clustered together with AtOFP1 and other members of this family that are known to regulate organ shape. Moreover, RsOFP2.3 expression was negatively correlated with tuberous root elongation after the cortex splitting stage, which made this gene the top candidate for the involvement of tuberous root shape. To further characterize the function of RsOFP2.3, it was ectopically expressed in Arabidopsis. RsOFP2.3 overexpression in Arabidopsis led to multiple phenotypical changes, especially the decreased length and increased width of the hypocotyl. Furthermore, RsOFP2.3 expression was induced by all the five classic plant hormones except ethylene, and it was most sensitive to exogenous gibberellic acid treatment. We also found that RsOFP2.3 was localized in the cytoplasm. Taken together, our results suggested the possible involvement for RsOFP2.3 in suppressing radish tuberous root elongation and that it encodes a functional protein which mainly inhibits the elongation of Arabidopsis aerial organs.

scholarly journals Gas Chromatographic Characterization of Silica Bonded with a Phenylpolysiloxane Film

1998 ◽  
Vol 16 (5) ◽  
pp. 319-329 ◽  
Author(s):  
T.M. Roshchina ◽  
K.B. Gurevich ◽  
A.Y. Fadeev
Keyword(s):  
Retention Volume ◽  
Specific Interaction ◽  
Retention Indices ◽  
Kováts Retention Indices ◽  
Initial Silica ◽  
Residual Silanol Groups ◽  
Chromatographic Characterization ◽  
Retention Parameters

A method of synthesizing modified silica with a dense grafted phenylpolysiloxane layer is described. Gas chromatography at zero surface coverage has been used for investigating the adsorption properties of both modified and initial silicas. It was shown that the thermodynamic parameters for retention (retention volume, Va; heat, q; and entropy, ΔS0, of adsorption) and the Kovats retention indices I for different classes of organic compounds are essentially changed with surface modification. The increase in Va and q for n-alkanes on phenyl-bonded silica was interpreted as due to penetration of the solutes into the grafted phenylpolysiloxane layer. The significant reduction in retention parameters for all compounds capable of specific interaction, including the formation of hydrogen bonds, on the phenyl-bonded silica relative to the initial silica has allowed conclusions to be drawn regarding the weak role of residual silanol groups in the retention process. These conclusions have been confirmed by a comparison of the chromatographic properties of phenyl-bonded silica and the polymethylphenylsiloxanes OV-17 and OV-25.

Digital x-ray mapping of nanometer-size supported bimetallic catalysts

1988 ◽  
Vol 46 ◽  
pp. 530-531
Author(s):  
L. T. Germinario
Keyword(s):  
Background Radiation ◽  
Metal Cluster ◽  
Single Element ◽  
Beam Diameter ◽  
X Rays ◽  
X Ray ◽  
Major Interest ◽  
Induced Changes

Understanding the role of metal cluster composition in determining catalytic selectivity and activity is of major interest in heterogeneous catalysis. The electron microscope is well established as a powerful tool for ultrastructural and compositional characterization of support and catalyst. Because the spatial resolution of x-ray microanalysis is defined by the smallest beam diameter into which the required number of electrons can be focused, the dedicated STEM with FEG is the instrument of choice. The main sources of errors in energy dispersive x-ray analysis (EDS) are: (1) beam-induced changes in specimen composition, (2) specimen drift, (3) instrumental factors which produce background radiation, and (4) basic statistical limitations which result in the detection of a finite number of x-ray photons. Digital beam techniques have been described for supported single-element metal clusters with spatial resolutions of about 10 nm. However, the detection of spurious characteristic x-rays away from catalyst particles produced images requiring several image processing steps.

The Role of Mitochondria in the Genesis of Neuroaxonal Dystrophy in the Brains of Aging Mice

1975 ◽  
Vol 33 ◽  
pp. 372-373
Author(s):  
J.E. Johnson
Keyword(s):  
Electron Microscopy ◽  
Present Report ◽  
Light And Electron Microscopy ◽  
Dorsal Column ◽  
Neuroaxonal Dystrophy ◽  
Nucleus Gracilis ◽  
Dystrophic Axons ◽  
The Brain ◽  
Nucleus Cuneatus

Although neuroaxonal dystrophy (NAD) has been examined by light and electron microscopy for years, the nature of the components in the dystrophic axons is not well understood. The present report examines nucleus gracilis and cuneatus (the dorsal column nuclei) in the brain stem of aging mice.Mice (C57BL/6J) were sacrificed by aldehyde perfusion at ages ranging from 3 months to 23 months. Several brain areas and parts of other organs were processed for electron microscopy.At 3 months of age, very little evidence of NAD can be discerned by light microscopy. At the EM level, a few axons are found to contain dystrophic material. By 23 months of age, the entire nucleus gracilis is filled with dystrophic axons. Much less NAD is seen in nucleus cuneatus by comparison. The most recurrent pattern of NAD is an enlarged profile, in the center of which is a mass of reticulated material (reticulated portion; or RP).

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