Mealiness assessment in fruits using MRI techniques.

Mealiness is a sensory attribute that cannot be defined by a single parameter but through a combination of variables (multidimensional structure). Previous studies propose the definition of mealiness as the lack of crispiness, of hardness and of juiciness. Current aims are focused on establishing non destructive tests for mealiness assessment. MultiSliceMultiEcho Magnetic resonance images (MRI, 64*64pixels) have been taken corresponding to a 3ms of Echo time. Small samples of Top Red apples stored 6 months at controlled atmosphere (expected to be non mealy) and 2°C (expected to be mealy) have been used for MRI imaging. Three out of four apples corresponding to the sample maintained at controlled atmosphere did not develop mealiness while three out of four fruits corresponding to the sample stored at 2°C became mealy after 6 month of storage. The minimum T2 values/image obtained for the mealy apples shows to be significantly lower when compared with non mealy apples pointing that a more dis-aggregated structure leads to a quicker loss of signal Also, there is a significant linear correlation (r=-0.76) between the number of pixels with a T2 value below 35ms within a fruit image and the deformation parameter registered during the Magness-Taylor firmness test. Finally, all the T2 images of the mealy apples show a regional variation of contrast which is not shown for non mealy apples. This variation of contrast is similar to the MRI images of water-cored apples indicating that in these cases there is a differential water movement that may precede the internal browning.

Fruit by fruit identification of mealy peaches. Extraction of storage features.

Mealiness is a negative attribute of sensory texture, characterised by the lack of juiciness decrease in the total amount of of water content of tissues. Peach mealy textures are known as \ and leatheriness. Besides the lack of juiciness and flavour, that characterises mealy fruits, in associated with internal browning near the stone and an incapacity of ripening although there i ripe appearance. It is considered as a physiological disorder that appears in stone fruits probably < unbalanced pectolitic enzyme activity during storage. Since January 1996, a wide EC Project entitled: "Mealiness in fruits. Consumer perception and i detection" is being carried out. Within it, the Physical Properties Laboratory (ETSIA-UPM) working to develop instrumental procedures to detect mealiness in different types of fruits (s contributions by Barreiro to AgEng). The results obtained have shown to correlate well with \ measurements in apples (Barreiro et al), also we have succeeded in identifying individual mealy j the basis of instrumental measurement in peaches. The definition of these texture categories will be used in further studies as a base for new individual classification.

Mealiness assessment in apples and peaches using MRI techniques.

Since Januarv 1946 a wade EC Project entitled "Mealiness in fruits Consumers perception and means for detection is being carried out. Mealiness is a sensory attribute that cannot be defined by a single parameter but through a combination of variables (multidimensional structure) Previous studies propose the definition of mealiness as the lack of crispiness of hardness and of juiciness. A destructive instrumental procedure combined with a integration technique has been already developed enabling to identify mealy fruits by destructive instrumental means use other contributions of Barreiro and Ortiz to this Ag Eng 98. Current aims .are focused on establishing non destructive tests for mealiness assessment. Magnetic resonance Imaging (MRI) makes use of the magnetic properties that some atomic nuclei have. especially hidrogen nuclei from water molecules to obtain high quality images in the field of internal quality evaluation the MRI has been used to assess internal injury due to conservation as o treatments as chilling injury un Persimmons Clark&Forbes (1994) and water-core in apples (Wang et al. 1998. In the case of persimmons the chilling injury is described as an initial tissue breakdown and lack of cohesion between cells followed by formation of a firm gel and by a lack of juiciness without changes in the total amount ol water content. Also a browning of the flesh is indicated (Clark&Forhes 1994). This definition fits into the previous description of mealiness.

Woolliness assessment in peaches (Cv. Springcrest) by sensory and instrumental means.

Mealiness is a negative attribute of sensory texture, characterised by the lack of juiciness without variation of total water content in the tissues. In peaches, mealiness is also known as "woolliness" and "leatheriness". This internal disorder is characterised by the lack of juiciness and flavour. In peaches, it is associated with interna browning near the stone and the incapacity of ripening although there is externa ripe appearance. Woolliness is associated with inadequate cold storage and is considered as a physiological disorder that appears in stone fruits when an unbalanced pectolitic enzyme activity during storage occurs (Kailasapathy and Melton, 1992). Many attempts have been carried out to identify and measure mealiness and woolliness in fruits. The texture of a food product is composed by a wide spectrum of sensory attributes. Consumer defines the texture integrating simultaneously all the sensory attributes. However, an instrument assesses one or several parameters related to a fraction of the texture spectrum (Kramer, 1973). The complexity of sensory analysis by means of trained panels to assess the quality of some producing processes, supports the attempt to estimate texture characteristics by instrumental means. Some studies have been carried out comparing sensory and instrumental methods to assess mealiness and woolliness. The current study is centered on analysis and evaluation of woolliness in peaches and is part of the European project FAIR CT95 0302 "Mealiness in fruits: consumer perception and means for detection". The main objective of this study was to develop procedures to detect woolly peaches by sensory and by instrumental means, as well as to compare both measuring procedures.

Disrupted splenic architecture, but normal lymph node development in mice expressing a soluble lymphotoxin-β receptor–IgG1 fusion protein

Early in ontogeny, the secondary lymphoid organs become populated with numerous cells of mesodermal origin which forms both the lymphoid and stromal elements. The critical receptor/ligand interactions necessary for lymphoid organogenesis to occur are for the most part unknown. Although lymphotoxin-α (LTα) has been shown to be required for normal lymph node, Peyer’s patch, and splenic development, it is unclear if soluble LTα3, and/or cell-bound lymphotoxin-αβ (LTαβ) mediate these developmental events. Here we report that blocking LTαβ/lymphotoxin-β receptor (LTβR) interaction in vivo by generating mice which express a soluble LTβR–Fc fusion protein driven by the human cytomegalovirus promoter results in an array of anatomic abnormalities affecting both the spleen and Peyer’s patches, but not the lymph nodes. These results demonstrate that surface LTαβ ligand plays a critical role in normal lymphoid organ development.

Mice transgenic for human CD4 and CCR5 are susceptible to HIV infection

HIV entry into human cells is mediated by CD4 acting in concert with one of several members of the chemokine receptor superfamily. The resistance to HIV infection observed in individuals with defective CCR5 alleles indicated that this particular chemokine receptor plays a crucial role in the initiation of in vivo HIV infection. Expression of human CD4 transgene does not render mice susceptible to HIV infection because of structural differences between human and mouse CCR5. To ascertain whether expression of human CD4 and CCR5 is sufficient to make murine T lymphocytes susceptible to HIV infection, the lck promoter was used to direct the T cell-specific expression of human CD4 and CCR5 in transgenic mice. Peripheral blood mononuclear cells and splenocytes isolated from these mice expressed human CD4 and CCR5 and were infectible with selected M-tropic HIV isolates. After in vivo inoculation, HIV-infected cells were detected by DNA PCR in the spleen and lymph nodes of these transgenic mice, but HIV could not be cultured from these cells. This indicated that although transgenic expression of human CD4 and CCR5 permitted entry of HIV into the mouse cells, significant HIV infection was prevented by other blocks to HIV replication present in mouse cells. In addition to providing in vivo verification for the important role of CCR5 in T lymphocyte HIV infection, these transgenic mice represent a new in vivo model for understanding HIV pathogenesis by delineating species-specific cellular factors required for productive in vivo HIV infection. These mice should also prove useful for the assessment of potential therapeutic and preventative modalities, particularly vaccines.

Ca2+/calmodulin-dependent protein kinase II phosphorylation of the presynaptic protein synapsin I is persistently increased during long-term potentiation

Long-term potentiation (LTP) is an increase in synaptic responsiveness thought to be involved in mammalian learning and memory. The localization (presynaptic and/or postsynaptic) of changes underlying LTP has been difficult to resolve with current electrophysiological techniques. Using a biochemical approach, we have addressed this issue and attempted to identify specific molecular mechanisms that may underlie LTP. We utilized a novel multiple-electrode stimulator to produce LTP in a substantial portion of the synapses in a hippocampal CA1 minislice and tested the effects of such stimulation on the presynaptic protein synapsin I. LTP-inducing stimulation produced a long-lasting 6-fold increase in the phosphorylation of synapsin I at its Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) sites without affecting synapsin I levels. This effect was fully blocked by either the N-methyl-d-aspartate receptor antagonist d(−)-2-amino-5-phosphonopentanoic acid (APV) or the CaM kinase II inhibitor KN-62. Our results indicate that LTP expression is accompanied by persistent changes in presynaptic phosphorylation, and specifically that presynaptic CaM kinase II activity and synapsin I phosphorylation may be involved in LTP expression.

Shifts of Intracellular pH Distribution as a Part of the Signal Mechanism Leading to the Elicitation of Benzophenanthridine Alkaloids1 : Phytoalexin Biosynthesis in Cultured Cells of Eschscholtzia californica

Cultured cells of Eschscholtzia californica (Californian poppy) respond to a yeast elicitor preparation or Penicillium cyclopium spores with the production of benzophenanthridine alkaloids, which are potent phytoalexins. Confocal pH mapping with the probe carboxy-seminaphthorhodafluor-1-acetoxymethylester revealed characteristic shifts of the pH distribution in challenged cells: within a few minutes after elicitor contact a transient acidification of cytoplasmic and nuclear areas occurred in parallel with an increase of the vacuolar pH. The change of proton concentration in the vacuole and in the extravacuolar area showed a nearly constant relation, indicating an efflux of vacuolar protons into the cytosol. A 10-min treatment with 2 mm butyric or pivalic acid caused a transient acidification of the cytoplasm comparable to that observed after elicitor contact and also induced alkaloid biosynthesis. Experimental depletion of the vacuolar proton pool reversibly prevented both the elicitor-triggered pH shifts and the induction of alkaloid biosynthesis. pH shifts and induction of alkaloid biosynthesis showed a similar dependence on the elicitor concentration. Net efflux of K+, alkalinization of the outer medium, and browning of the cells were evoked only at higher elicitor concentrations. We suggest that transient acidification of the cytoplasm via efflux of vacuolar protons is both a necessary and sufficient step in the signal path toward biosynthesis of benzophenanthridine alkaloids in Californian poppy cells.

Equine rhinovirus 1 is more closely related to foot-and-mouth disease virus than to other picornaviruses.

Equine rhinovirus 1 (ERhV1) is a respiratory pathogen of horses which has an uncertain taxonomic status. We have determined the nucleotide sequence of the ERhV1 genome except for a small region at the 5' end. The predicted polyprotein was encoded by 6741 nucleotides and possessed a typical picornavirus proteolytic cleavage pattern, including a leader polypeptide. The genomic structure and predicted amino acid sequence of ERhV1 were more similar to those of foot-and-mouth disease viruses (FMDVs), the only members of the aphthovirus genus, than to those of other picornaviruses. Features which were most similar to FMDV included a 16-amino acid 2A protein which was 87.5% identical in sequence of FMDV 2A, a leader (L) protein similar in size to FMDV Lab and the possibility of a truncated L protein similar in size to FMDV Lb, and a 3C protease which recognizes different cleavage sites. However, unlike FMDV, ERhV1 had only one copy of the 3B (VPg) polypeptide. The phylogenetic relationships of the ERhV1 sequence and nucleotide sequences of representative species of the five genera of the family Picornaviridae were examined. Nucleotide sequences coding for the complete polyprotein, the RNA polymerase, and VP1 were analyzed separately. The phylogenetic trees confirmed that ERhV1 was more closely related to FMDV than to other picornaviruses and suggested that ERhV1 may be a member, albeit very distant, of the aphthovirus genus.

Expression of a single-chain HLA class I molecule in a human cell line: presentation of exogenous peptide and processed antigen to cytotoxic T lymphocytes.

We have synthesized a recombinant gene encoding a single-chain HLA-A2/beta 2-microglobulin (beta 2m) molecule by linking beta 2m through its carboxyl terminus via a short peptide spacer to HLA-A2 (A*0201). This gene has been expressed in the beta 2m-deficient colorectal tumor cell line DLD-1. Transfection of this cell with the single-chain construct was associated with conformationally correct cell surface expression of a class I molecule of appropriate molecular mass. The single-chain HLA class I molecule presented either exogenously added peptide or (after interferon-gamma treatment) endogenously processed antigen to an influenza A matrix-specific, HLA-A2-restricted cytotoxic T-lymphocyte line. The need for interferon gamma for the processing and presentation of endogenous antigen suggests that DLD-1 has an antigen-processing defect that can be up-regulated, a feature that may be found in other carcinomas. Our data indicate that single-chain HLA class I constructs can form functional class I molecules capable of presenting endogenously processed antigens. Such molecules should be of use for functional studies, as well as providing potential anticancer immunotherapeutic agents or vaccines.

Function of the p86 subunit of eukaryotic initiation factor (iso)4F as a microtubule-associated protein in plant cells.

The isozyme form of eukaryotic initiation factor 4F [eIF-(iso)4F] from wheat germ is composed of a p28 subunit that binds the 7-methylguanine cap of mRNA and a p86 subunit having unknown function. The p86 subunit was found to have limited sequence similarity to a kinesin-like protein encoded by the katA gene of Arabidopsis thaliana. Native wheat germ eIF-(iso)4F and bacterially expressed p86 subunit and p86-p28 complex bound to taxol-stabilized maize microtubules (MTs) in vitro. Binding saturation occurred at 1 mol of p86 per 5-6 mol of polymerized tubulin dimer, demonstrating a substoichiometric interaction of p86 with MTs. No evidence was found for a direct interaction of the p28 subunit with MTs. Unlike kinesin, cosedimentation of eIF-(iso)4F with MTs was neither reduced by MgATP nor enhanced by adenosine 5'-[gamma-imido]triphosphate. Both p86 subunit and p86-p28 complex induced the bundling of MTs in vitro. The p86 subunit was immunolocalized to the cytosol in root maize cells and existed in three forms: fine particles, coarse particles, and linear patches. Many coarse particles and linear patches were colocalized or closely associated with cortical MT bundles in interphase cells. The results indicate that the p86 subunit of eIF-(iso)4F is a MT-associated protein that may simultaneously link the translational machinery to the cytoskeleton and regulate MT disposition in plant cells.

The crystal structure of an N-terminal two-domain fragment of vascular cell adhesion molecule 1 (VCAM-1): a cyclic peptide based on the domain 1 C-D loop can inhibit VCAM-1-alpha 4 integrin interaction.

Vascular cell adhesion molecule 1 (VCAM-1) represents a structurally and functionally distinct class of immunoglobulin superfamily molecules that bind leukocyte integrins and are involved in inflammatory and immune functions. X-ray crystallography defines the three-dimensional structure of the N-terminal two-domain fragment that participates in ligand binding. Residues in domain 1 important for ligand binding reside in the C-D loop, which projects markedly from one face of the molecule near the contact between domains 1 and 2. A cyclic peptide that mimics this loop inhibits binding of alpha 4 beta 1 integrin-bearing cells to VCAM-1. These data demonstrate how crystallographic structural information can be used to design a small molecule inhibitor of biological function.

Versiones en español de películas de género fantástico en el Hollywood de los años treinta del siglo XX

A finales de la década de los años veinte el cine mudo estaba llegando a su fin y comenzaron a producirse masivamente películas habladas. Los grandes estudios de Hollywood temen perder público fuera de Estados Unidos y antes de decidirse por el doblaje, ya que este sistema presentaba en aquella época problemas de sincronización, comienzan filmar versiones múltiples de un mismo guion en diferentes idiomas para exportar a los países de habla no inglesa. Dentro de todas las películas en español producidas por Hollywood, esta tesis doctoral está centrada únicamente en las de género fantástico. Es cierto que en las versiones en español encontramos pocas de dicho género, pero dentro de las existentes hay películas muy variadas, desde películas totalmente de género como las dos versiones de Drácula hasta otras que contienen elementos fantásticos lo suficientemente interesantes como para ser incluidas en esta investigación. La mayoría de las versiones en español que se produjeron en la década de los años treinta eran comedias o melodramas, los dos géneros más populares de la época. Pero de las más de cien películas en español que se filmaron en Hollywood durante la década de los años treinta algunas pueden catalogarse dentro del género fantástico. Estas películas son: ¡Pobre infeliz! (Charles Rogers, 1930), versión en español de The Shrimp (Ídem, Charles Rogers ,1930); Noche de duendes (James Parrott, 1930), versión en español de The Laurel-Hardy Murder Case (Ídem, James Parrot, 1930); La voluntad del muerto (George Melford, 1930), versión en español de The Cat Creeps (Rupert Julian, John Willard, 1930); Wu Li Chang (Nick Grinde, 1930), versión en español de Mr. Wu (William Night, 1927); Drácula (George Melford, 1931), versión en español de Drácula (Dracula, Tod Browning, 1931); Cheri-Bibi (Carlos F. Borcosque, 1931), versión en español de The Phantom of Paris (Ídem, John S. Robertson, 1931) y El último varón sobre la tierra (James Tinling, 1933), versión en español de It's Great to Be Alive (Alfred L. Werker, 1933)...

Effiziente Spurensicherung im Waffenlauf

Schüsse mit aufgesetzter Waffenmündung können biologische Antragungen im Waffenlauf hinterlassen, die durch Endoskopie optisch und durch PCR analytisch detektiert werden können. Im Rahmen des vom SNF geförderten Projektes wurden verschiedene Verfahren der Spurensicherung überprüft. Mit Vlies abgedeckte Farbpads (2 ml Acrylfarbe, 2 ml Humanblut, 1 ml Bariumsulfat) wurden in 12 cm grosse Gelatinewürfel integriert. Diese wurden mit aufgesetzter Waffenmündung mit verschiedenen Pistolen im Kaliber 7.65 mm Browning beschossen und die Waffenläufe endoskopiert. Die Spurensicherung erfolgte getrennt für den vorderen und den hinteren Laufabschnitt und wurde in mehreren Testreihen mit folgenden Mitteln durchgeführt: Wattetupfer (Holzstäbchen, Applimed), Forensic Swab (Sarstedt), COPAN FLOQSwab™, DNA-freie VFG-Filz-Stopfen. Anschliessend erfolgte eine endoskopische Kontrolle. Der DNA-Gehalt wurde mittels qPCR ermittelt. Grundsätzlich waren alle Verfahren für die Spurensicherung geeignet und erzielten eine gute Spurenausbeute. Wesentliche Unterschiede ergaben sich in der Handhabung. Holzstäbchen waren lang genug, jedoch rigide, was bisweilen zu ihrem Abbruch führte, andererseits aber guten Abrieb ergab. Der Forensic Swab war mit seinem flexiblen Kunststoffstiel leichter von hinten im Waffenlauf anzuwenden, was ihn auch für schwer zugängliche Stellen empfiehlt. Am einfachsten war eine gründliche Spurensicherung mit den FLOQs zu erreichen. Durch deren Nylonbürste wurde eine gute Abriebleistung bei flexiblem Stiel erzielt. FLOQs mit verschiedener Länge ermöglichten eine kontrollierte Spurennahme insbesondere im hinteren Teil des Waffenlaufes. FLOQs waren auch im molekular-biologischen Labor leicht zu verarbeiten. Mit den DNA-frei gemachten, kalibrierten VFG-Stopfen liessen sich restliche Spuren in teils erheblicher Konzentration mobilisieren. Allerdings sind Handhabung und Weiterverarbeitung im DNA-Labor wesentlich aufwändiger.

Stable carbon isotope record of sediment core Bass_River_Site

A thick, apparently continuous section recording events of the latest Paleocene thermal maximum in a neritic setting was drilled at Bass River State Forest, New Jersey as part of ODP Leg 174AX [Miller, Sugarman, Browning et al., 1998]. Integrated nannofossil and magneto-stratigraphy provides a firm chronology supplemented by planktonic foraminiferal biostratigraphy. This chronologic study indicates that this neritic section rivals the best deep-sea sections in providing a complete record of late Paleocene climatic events. Carbon and oxygen isotopes measured on benthic foraminifera show a major (4.0% in carbon, 2.3% in oxygen) negative shift correlative with the global latest Paleocene carbon isotope excursion (CIE). A sharp increase in kaolinite content coincides with the isotope shift in the Bass River section, analogous to increases found in several other records. Carbon and oxygen isotopes remain low and kaolinite content remains high for the remainder of the depositional sequence above the CIE (32.5 ft, 9.9 m), which we estimate to represent 300-500 k.y. We interpret these data as indicative of an abrupt shift to a warmer and wetter climate along the North American mid-Atlantic coast, in concert with global events associated with the CIE.