Identification, by RT-PCR, of eight novel I2-conotoxins from the worm-hunting cone snails Conus brunneus, Conus nux, and Conus princeps from the eastern Pacific (Mexico).

Marine snails of the genus Conus (∼500 species) are tropical predators that produce venoms for capturing prey, defense and competitive interactions. These venoms contain 50-200 different peptides ("conotoxins") that generally comprise 7-40 amino acid residues (including 0-5 disulfide bridges), and that frequently contain diverse posttranslational modifications, some of which have been demonstrated to be important for folding, stability, and biological activity. Most conotoxins affect voltage- and ligand-gated ion channels, G protein-coupled receptors, and neurotransmitter transporters, generally with high affinity and specificity. Due to these features, several conotoxins are used as molecular tools, diagnostic agents, medicines, and models for drug design. Based on the signal sequence of their precursors, conotoxins have been classified into genetic superfamilies, whereas their molecular targets allow them to be classified into pharmacological families. The objective of this work was to identify and analyze partial cDNAs encoding precursors of conotoxins belonging to I superfamily from three vermivorous species of the Mexican Pacific coast: C. brunneus, C. nux and C. princeps. The precursors identified contain diverse numbers of amino acid residues (C. brunneus, 65 or 71; C. nux, 70; C. princeps, 72 or 73), and all include a highly conserved signal peptide, a C-terminal propeptide, and a mature toxin. All the latter have one of the typical Cys frameworks of the I-conotoxins (C-C-CC-CC-C-C). The prepropeptides belong to the I2-superfamily, and encode eight different hydrophilic and acidic mature toxins, rather similar among them, and some of which have similarity with I2-conotoxins targeting voltage- and voltage-and-calcium-gated potassium channels.

Physical and antibacterial properties of edible films formulated with apple skin polyphenols.

Fruit and vegetable skins have polyphenolic compounds, terpenes, and phenols with antimicrobial and antioxidant activity. These flavoring plant essential oil components are generally regarded as safe. Edible films made from fruits or vegetables containing apple skin polyphenols have the potential to be used commercially to protect food against contamination by pathogenic bacteria. The main objective of this study was to evaluate physical properties as well as antimicrobial activities against Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella enterica of apple skin polyphenols at 0% to 10% (w/w) concentrations in apple puree film-forming solutions formulated into edible films. Commercial apple skin polyphenol powder had a water activity of 0.44 and high total soluble phenolic compounds and antioxidant capacity (995.3 mg chlorogenic acid/100 g and 14.4 mg Trolox/g, respectively). Antimicrobial activities of edible film containing apple skin polyphenols were determined by the overlay method. Apple edible film with apple skin polyphenols was highly effective against L. monocytogenes. The minimum concentration need to inactive L. monocytogenes was 1.5%. However, apple skin polyphenols did not show any antimicrobial effect against E. coli O157:H7 and S. enterica even at 10% level. The presence of apple skin polyphenols reduced water vapor permeability of films. Apple skin polyphenols increased elongation of films and darkened the color of films. The results of the present study show that apple skin polyphenols can be used to prepare apple-based antimicrobial edible films with good physical properties for food applications by direct contact.

Gelation, oxygen permeability, and mechanical properties of mammalian and fish gelatin films.

The objective of this study was to evaluate the gelation, thermal, mechanical, and oxygen permeability properties of different mammalian, warm- and cold-water fish gelatin solutions and films. Mammalian gelatin solutions had the highest gel set temperatures, followed by warm-water fish and then cold-water fish gelatin solutions. These differences were related to concentrations of imino acids present in each gelatin, with mammalian gelatin having the highest and cold-water fish gelatin having the lowest concentrations. Mammalian and warm-water fish gelatin films contained helical structures, whereas cold-water fish gelatin films were amorphous. This was due to the films being dried at room temperature (23 °C), which was below or near the gelation temperatures of mammalian and warm-water fish gelatin solutions and well above the gelation temperature of cold-water fish gelatin solutions. Tensile strength, percent elongation, and puncture deformation were highest in mammalian gelatin films, followed by warm-water fish gelatin film and then by cold-water fish gelatin films. Oxygen permeability values of cold-water fish gelatin films were significantly lower than those for mammalian gelatin films. These differences were most likely due to higher moisture sorption in mammalian gelatin films, leading to higher oxygen diffusivity.

Effects of allspice, cinnamon, and clove bud essential oils in edible apple films on physical properties and antimicrobial activities.

Essential oils (EOs) derived from plants are rich sources of volatile terpenoids and phenolic compounds. Such compounds have the potential to inactivate pathogenic bacteria on contact and in the vapor phase. Edible films made from fruits or vegetables containing EOs can be used commercially to protect food against contamination by pathogenic bacteria. EOs from cinnamon, allspice, and clove bud plants are compatible with the sensory characteristics of apple-based edible films. These films could extend product shelf life and reduce risk of pathogen growth on food surfaces. This study evaluated physical properties (water vapor permeability, color, tensile properties) and antimicrobial activities against Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes of allspice, cinnamon, and clove bud oils in apple puree film-forming solutions formulated into edible films at 0.5% to 3% (w/w) concentrations. Antimicrobial activities were determined by 2 independent methods: overlay of the film on top of the bacteria and vapor phase diffusion of the antimicrobial from the film to the bacteria. The antimicrobial activities against the 3 pathogens were in the following order: cinnamon oil > clove bud oil > allspice oil. The antimicrobial films were more effective against L. monocytogenes than against the S. enterica. The oils reduced the viscosity of the apple solutions and increased elongation and darkened the colors of the films. They did not affect water vapor permeability. The results show that apple-based films with allspice, cinnamon, or clove bud oils were active against 3 foodborne pathogens by both direct contact with the bacteria and indirectly by vapors emanating from the films.

Antibacterial effects of allspice, garlic, and oregano essential oils in tomato films determined by overlay and vapor-phase methods.

Physical properties as well as antimicrobial activities against Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes of allspice, garlic, and oregano essential oils (EOs) in tomato puree film-forming solutions (TPFFS) formulated into edible films at 0.5% to 3% (w/w) concentrations were investigated in this study. Antimicrobial activities were determined by 2 independent methods: overlay of the film on top of the bacteria and vapor-phase diffusion of the antimicrobial from the film to the bacteria. The results indicate that the antimicrobial activities against the 3 pathogens were in the following order: oregano oil > allspice oil > garlic oil. Listeria monocytogenes was less resistant to EO vapors, while E. coli O157:H7 was more resistant to EOs as determined by both overlay and vapor-phase diffusion tests. The presence of plant EO antimicrobials reduced the viscosity of TPFFS at the higher shear rates, but did not affect water vapor permeability of films. EOs increased elongation and darkened the color of films. The results of the present study show that the 3 plant-derived EOs can be used to prepare tomato-based antimicrobial edible films with good physical properties for food applications by both direct contact and indirectly by vapors emanating from the films.

Antibacterial activity against E. coli O157:H7, physical properties, and storage stability of novel carvacrol-containing edible tomato films.

Edible films containing plant antimicrobials are gaining importance as potential treatment to extend product shelf life and reduce risk of pathogen growth on contaminated food surfaces. The main objective of the present study was to evaluate the antimicrobial activities, storage stabilities, and physical-chemical-mechanica1 properties of novel edible films made from tomatoes containing carvacrol, the main constituent of oregano oil. The antimicrobial activities against E. coli O157:H7 and the stability of carvacrol were evaluated during the preparation and storage of tomato-based films made by 2 different casting methods, continuous casting and batch casting. Antimicrobial assays of tomato films indicated that optimum antimicrobial effects occurred with carvacrol levels of approximately 0.75% added to tomato purees before film preparation. HPLC analysis of the films indicated that the carvacrol concentrations and bactericidal effect of the films remained unchanged over the storage period of up to 98 d at 5 and 25 degrees C. Carvacrol addition to the tomato puree used to prepare the films increased water vapor permeability of tomato films. The continuous method for casting of the films appears more suitable for large-scale use than the batch method. This 1st report on tomato-based edible antimicrobial tomato films suggests that these films have the potential to prevent adverse effects of contaminated food and promote human health associated with the consumption of tomatoes.

Properties of novel hydroxypropyl methylcellulose films containing chitosan nanoparticles.

In this study, chitosan nanoparticles were prepared and incorporated in hydroxypropyl methylcellulose (HPMC) films under different conditions. Mechanical properties, water vapor and oxygen permeability, water solubility, and scanning and transmission electron microscopy (SEM and TEM) results were analyzed. Incorporation of chitosan nanoparticles in the films improved their mechanical properties significantly, while also improving film barrier properties significantly. The chitosan poly(methacrylic acid) (CS-PMAA) nanoparticles tend to occupy the empty spaces in the pores of the HPMC matrix, inducing the collapse of the pores and thereby improving film tensile and barrier properties. This study is the first to investigate the use of nanoparticles for the purpose of strengthening HPMC films.

Effect of berry size and sodium hydroxide pretreatment on the drying characteristics of blueberries under infrared radiation heating.

This research studied the effect of berry size and dipping pretreatment in hot sodium hydroxide (NaOH) solution on the drying characteristics of blueberries under infrared radiation (IR) heating. Changes in the microstructure and diffusion coefficient of the berries after the NaOH pretreatment were also determined using scanning electronic microscopy and dynamic vapor sorption (DVS), respectively. To quantify the effect of berry size, non-pretreated bulk blueberries were sorted into 6 groups based on their diameters and dried at 70 degrees C. To determine the effectiveness of NaOH pretreatment in improving drying characteristics, bulk blueberries of different sizes, both nonpretreated and NaOH pretreated, were dried at constant temperatures of 80 and 90 degrees C, and variable temperatures of 70 degrees C for 50 min followed by 90 degrees C for 50 min. The NaOH pretreatment dipped blueberries in 0.1% NaOH solution with fruit to solution ratio 1:1 (w/v) at initial temperature of 93 degrees C for 5 s. Results showed that the drying rate increased with decreased berry size. Average moisture diffusivity was in the range of 5.89 to 8.13 m2/s at 70 degrees C. The NaOH pretreatment increased drying rate and moisture diffusivity and reduced the number of broken berries, especially at high drying temperatures. Results from SEM observation and DVS showed that the increase in diffusivity coefficients of berry coat and loss of intact microstructure in coat and tissue cells might contribute to the effect of NaOH pretreatment on the IR drying of blueberries.

[Histopathology of mucocutaneous leishmaniasis caused by Leishmania (Vianna) braziliensis]. / Histopathologie de la leishmaniose cutanéo-muqueuse à Leishmania (Viannia) braziliensis.

A histopathological study of mucocutaneous leishmaniasis due to Leishmania (Viannia) braziliensis was carried out on 28 cutaneous and 114 mucosal biopsies, taken from Bolivian and Peruvian patients. This study showed similar histopathological findings in cutaneous and mucosal lesions. The cutaneous biopsies showed a strong epidermal hyperplasia occasionnally budding in the dermis. In the ulcerative area, the epidermis was totally necrosed and replaced by a fibrino-leucocytic edge. In the dermis, histio-lympho-plasmocytic infiltration was constantly found. The histiocytes often gathered in follicles sometimes with diffuse fibrosis. The parasites were encountered in 28.6 p. 100 of the biopsies. Whatever the mucosa concerned (i.e. nasal, palatal or lingual), the mucosal lesion was not different from the cutaneous lesion. The malpighian epithelium is either absent or the seat of a pseudo-epitheliomatous hyperplasia. Major histio-lympho-plasmocytic infiltration was found and extended through the depth of the lamina propria. Suppurative and fibrinoid necroses coexisted superficially and sometimes penetrated in depth. The parasites were found in about 30 p. 100 of the cases.

[Epidemiological, clinical and biological features of mucocutaneous leishmaniasis in Bolivia after a 221 patient sample]. / Particularités épidémiologiques, cliniques et biologiques de la leishmaniose cutanéo-muqueuse en Bolivie d'après un échantillon de 221 malades.

The authors present a clinical, biological and epidemiological study of 221 cases of mucocutaneous leishmaniasis observed in Bolivia between January 1990 and April 1991. The patients exhibited cutaneous lesions in 136 cases and mucous involvement in 85 cases. It is stressed on the severity of the disease in Bolivia.

Parasitological diagnosis of mucocutaneous leishmaniasis due to Leishmania b. braziliensis in Bolivia.

Parasitological diagnosis, using stained smears, culture and pathological examination of biopsy, was studied in 146 patients infected with mucocutaneous leishmaniasis, in Bolivia and Peru. The most efficient parasite detecting technique appeared to be the smear examination in cutaneous lesions (33% positive) and the pathology in case of mucous lesions (28% positive). In both, cutaneous and mucous lesions, the parasites were found most frequently in old lesions.

[Pituitary-gonadal hormonal evaluation in male patients with alcoholic liver cirrhosis]. / Evaluación hormonal hipofiso-gonadal en pacientes masculinos con cirrosis hepática alcohólica.

Pituitary-gonadal plasmatic hormonal values were measured in 26 alcoholic cirrhotic males and 20 healthy subjects. Total testosterone and luteinizing hormone mean levels were lower in the cirrhotic group (p < 0.05). Estradiol and prolactin were significant higher (p < 0.05 and p < 0.001, respectively). Follicle stimulation hormone mean values were normal. Pituitary-gonadal axis luteinizing hormone-testosterone and follicle stimulating hormone-estradiol were abnormal since the retrofeedback mechanism failed to work in each system. These results show a wide disturbance of the sexual hormonal function in our patients which certainly contributes to puzzle the complexity of the clinical and therapeutic aspects in these kind of patients.

Fabrica de valvulas y grifos de bronce para baja presion

Mercado.- Mediante el presente capitulo se ha establecido la existencia de un amplio mercado para grifos y valvulas de baja presion, llegandose a determinar que la demanda proyectada muestra un mercado que va desde 231.314 kg. para 1974 hasta 277.264 para 1964, sobre todo si hasta el momento las necesidades de estos productos han sido satisfechos mediante importaciones. Localizacion de la Planta.- En este capitulo se realizo el analisis de todos los factores llamados locacionales para poder determinar el emplazamiento de la planta.Para tal efecto, se ha hecho uso del metodo de los puntos o balanceo de factores, llegandose a determinar que el lugar geografico de mayor puntaje es La Paz, lugar donde se localizara la fabrica Tamaño de la Planta.- Capitulo que trata de la determinacion de la capacidad de produccion de la planta. El calculo del tamaño optimo da como resultado una capacidad de 248.432 kilogramos, capacidad que llegaria a cubrir la demanda del año 1978, lo cual nos indica que en los futuros años se tendria un mercado insatisfecho; por tal razon, la planta fue dimensionada con una capacidad real de 280.000 kilos/año Ingenieria del Proyecto.-En el capitulo denominado ingenieria del proyecto, se considera todos los aspectos tecnicos del proyecto, asi se muestra el calculo y dimensionamiento de las valvulas y grifos, perdida de carga en las valvulas, la aleacion tipo a usarse formada por 85 de cobre, 5 de plomo, 5 de estaño, 5 de zing, construccion de los modelos y moldes para la colada, arenas para los moldes procedentes del lago Titicaca.