New Saccharomyces cerevisiae baker's yeast displaying enhanced resistance to freezing   总被引：3，自引：0，他引：3  

Codón AC  Rincón AM  Moreno-Mateos MA  Delgado-Jarana J  Rey M  Limón C  Rosado IV  Cubero B  Peñate X  Castrejón F  Benítez T 《Journal of agricultural and food chemistry》2003,51(2):483-491

Three procedures were used to obtain new Saccharomyces cerevisiae baker's yeasts with increased storage stability at -20, 4, 22, and 30 degrees C. The first used mitochondria from highly ethanol-tolerant wine yeast, which were transferred to baker's strains. Viability of the heteroplasmons was improved shortly after freezing. However, after prolonged storage, viability dramatically decreased and was accompanied by an increase in the frequency of respiratory-deficient (petite) mutant formation. This indicated that mitochondria were not stable and were incompatible with the nucleus. The strains tested regained their original resistance to freezing after recovering their own mitochondria. The second procedure used hybrid formation after protoplast fusion and isolation on selective media of fusants from baker's yeast meiotic products resistant to parafluorphenylalanine and cycloheximide, respectively. No hybrids were obtained when using the parentals, probably due to the high ploidy of the baker's strains. Hybrids obtained from nonisogenic strains manifested in all cases a resistance to freezing intermediate between those of their parental strains. Hybrids from crosses between meiotic products of the same strain were always more sensitive than their parentals. The third method was used to develop baker's yeast mutants resistant to 2-deoxy-d-glucose (DOG) and deregulated for maltose and sucrose metabolism. Mutant DOG21 displayed a slight increase in trehalose content and viability both in frozen doughs and during storage at 4 and 22 degrees C. This mutant also displayed a capacity to ferment, under laboratory conditions, both lean and sweet fresh and frozen doughs. For industrial uses, fermented lean and sweet bakery products, both from fresh and frozen doughs obtained with mutant DOG21, were of better quality with regard to volume, texture, and organoleptic properties than those produced by the wild type.  相似文献   

Energy Metabolism in Fish Tissues Related to Osmoregulation and Cortisol Action     

Raúl Laiz-Carrión  Susana Sangiao-Alvarellos  José M. Guzmán  María P. Martín del Río  Jesús M. Míguez  José L. Soengas  Juan M. Mancera 《Fish physiology and biochemistry》2002,27(3-4):179-188

This is an overview of our recent studies of energy metabolism in fish brain and other organs regulated by exogenous (feeding, salinity) and endogenous (hormones) factors. To highlight our approach, we present latest results concerned osmoregulation in the gills of gilthead seabream, Sparus auratus. Our model, the seabream, is a euryhaline teleost capable of adaptation to extreme changes in environmental salinity. Treatment with cortisol allowed us to achieve circulating cortisol levels similar to those observed during osmotic adaptation and to assess how elevated hormonal levels affected simultaneously metabolic and osmoregulatory capacities of the gill tissue. Cortisol-implanted fish showed higher gill Na⁺,K⁺-ATPase activity than control fish but no changes were observed in plasma osmolality and ion levels. Plasma levels of glucose and lactate increased in cortisol-implanted fish while protein levels decreased. Cortisol treatment elicited metabolic changes in liver and brain reflecting an activation of the glycogenic and gluconeogenic potential in liver, and the glycogenic potential in brain, which are confirmatory of data obtained in previous experiments. In gills, we demonstrated that cortisol treatment elicited changes in their energy metabolism that can be summarized as a decreased capacity in the use of exogenous glucose (decreased HK activity), a decrease in the capacity of the pentose phosphate pathway (decreased G6PDH activity), and an increased glycolytic potential (increased PK activity). Observed metabolic changes in gills can be associated with those occurring in nature during osmotic adaptation in the same fish species.  相似文献   

Effects of salinity on osmoregulation during the embryonic development of the bullseye puffer (Sphoeroides annulatus Jenyns 1842)          下载免费PDF全文

Javier Pérez‐Robles  Fernando Diaz  Leonardo Ibarra‐Castro  Ivone Giffard‐Mena  Ana Denise Re  Luz Estela Rodríguez Ibarra  Jesús Armando Ibarra Soto 《Aquaculture Research》2016,47(3):838-846

To evaluate the effect of salinity on the hatching rate, hatching time, survival percentage, osmoregulation pattern and the incidence of abnormalities in newly hatched larvae, embryos of Sphoeroides annulatus (Jenyns 1842) were exposed to 5, 12, 19, 26, 33, 35 and 40 psu. The hatching percentage (HP), survival percentage (PS), normal larvae (PN), deformed larvae (PD) and hatching time (HT) were significantly affected by salinity (P < 0.05). The embryos exposure to 5 psu caused that HP, PS, and PN had lower values (2.6 ± 0.32, 7.78 ± 0.88 and 70.37 ± 7.75% respectively), PD and HT had the highest values 26.67 ± 7.54% and 55.53 ± 0.59 h respectively. However, the survival of newly hatched larvae was not possible in 5 ups, though it was in 40 ups. Osmotic pressure (OP) remained constant in each salinity, whereas isosmotic points changed from 435.5 mOsm kg^?1 in 21 h post fertilization to 342.8 mOsm kg^?1 at 47 h post fertilization, obtaining a pattern of hyper‐osmoregulation at lower salinities and hypo‐osmoregulation in higher salinities. This study is the first carried out on embryos of this species; therefore, the obtained information is essential to improve strategies and growing conditions in their initial development.  相似文献   

Dietary fulvic acid effects on survival and expression of immune‐related genes in Litopenaeus vannamei challenged with Vibrio parahaemolyticus          下载免费PDF全文

Jesús A. Fierro‐Coronado  Carlos Angulo  Arturo Rubio‐Castro  Antonio Luna‐González  Carlos J. Cáceres‐Martínez  Cesar A. Ruiz‐Verdugo  Píndaro Álvarez‐Ruíz  Ruth Escamilla‐Montes  Héctor A. González‐Ocampo  Genaro Diarte‐Plata 《Aquaculture Research》2018,49(9):3218-3227

The effects of fulvic acid (FA) on survival and immune‐related gene expression were investigated in Litopenaeus vannamei challenged with Vibrio parahaemolyticus by immersion. Shrimp were fed with different dietary FA concentrations (1, 2, 4 and 6 g/kg feed) for 20 days (first bioassay) or 8 days (second bioassay, 2 g/kg feed of FA added every 2 days) and then challenged with V. parahaemolyticus. In a third bioassay, the expression of three immune‐related genes (translationally controlled tumour protein [TCTP], superoxide dismutase [SOD] and heat‐shock protein 70 [HSP70]) in haemocytes or hepatopancreas of experimental shrimp was measured by real‐time quantitative PCR at 0, 6, 12, 24, 48, 72 and 96 hr after FA (2 g/kg feed) administration. Fulvic acid increased survival at a concentration of 2 g/kg feed supplied every two days. Interestingly, TCTP gene expression was upregulated, whereas gene expression of SOD and HSP70 was downregulated. In conclusion, dietary fulvic acid improves survival in white shrimp challenged with V. parahaemolyticus and modulates the immune response. Therefore, FA merits further evaluation as prophylactic treatment in commercial shrimp farms.  相似文献   

Rhodamine-pink as a genetic marker for yeast populations in wine fermentation     

Ambrona J  Vinagre A  Maqueda M  Alvarez ML  Ramírez M 《Journal of agricultural and food chemistry》2006,54(8):2977-2984

Winemaking with selected yeasts requires simple techniques to monitor the inoculated yeast. New high-concentration rhodamine-resistant mutants and low-concentration rhodamine-pink mutants, easy to detect by replica-plate assay, were obtained from selected wine yeasts. The rhodamine-pink mutations were dominant and were located at the pdr5 locus that encodes for the Pdr5 ATP-binding cassette multidrug resistance transporter. The mutants were genetically stable but had lost the killer phenotype of the parent yeast strain. They were genetically improved by elimination of recessive growth-retarding alleles followed by crossing with selected killer wine yeasts. Several spore-clones were selected according to their must fermentation kinetics and the organoleptic quality of the wine. Some spore-clones were tested in industrial winemaking, and they were easily monitored during must fermentation using a simple color-plate assay. They accounted for >96% of the total yeasts in the must, and the resulting wine had as good a quality as those made with standard commercial wine yeasts. The rhodamine-pink yeasts may also be detected by direct seeding onto rhodamine agar or by observation under fluorescence microscopy. These possibilities greatly reduce the time of analysis and make the monitoring procedure for rhodamine-pink yeasts faster, easier, and cheaper than for the genetically marked wine yeasts obtained previously.  相似文献   

Shelter and lighting in the intensive rearing of juvenile crayfish (Pacifastacus leniusculus,Astacidae) from the onset of exogenous feeding     

Rocío González  Jesús Domingo Celada  Vanesa García  José Manuel Carral  Álvaro González  María Sáez‐Royuela 《Aquaculture Research》2011,42(3):450-456

Recent advances on feeding in intensive rearing of juvenile astacids enable research of other factors influencing growth and survival without the confounding effect of inadequate feeding. Two experiments were conducted to evaluate the effects of the number of shelters per crayfish and to test different lighting conditions. Stage 2 juvenile Pacifastacus leniusculus were stocked in fibreglass tanks and fed a dry diet for salmonids combined with restricted amounts of decapsulated Artemia cysts. In experiment 1, four, two or one shelters per crayfish were tested for 80 days. No significant differences were found among groups either in survival (final mean: 86.67%) or in growth [final mean: 11.41 mm mean carapace length (CL), 355.45 mg mean weight]. In experiment 2, three lighting conditions were tested for 120 days: continuous lighting of 925 lx, continuous darkness and natural photoperiod. Survival rates ranged from 76.7% to 88.3%, with no significant differences among groups. The crayfish kept under continuous darkness grew faster (final mean: 12.70 mm CL, 543.08 mg weight) than those reared under the other two light conditions. This study shows that, under improved feeding conditions, a minimum number of shelters can be provided, and faster growth can be obtained in continuous darkness.  相似文献   

Response of juvenile tench (Tinca tinca L.) fed practical diets with different protein contents and substitution levels of fish meal by soybean meal          下载免费PDF全文

Vanesa García  Jesús Domingo Celada  Rocío González  José Manuel Carral  María Sáez‐Royuela  Álvaro González 《Aquaculture Research》2015,46(1):28-38

A basal practical diet for juvenile tench (Tinca tinca) was formulated and elaborated to test several protein contents and substitution possibilities of fish meal (FM) by soybean meal (SBM) in a 90‐day trial with 5‐month‐old juveniles (30.54 mm TL, 0.30 g W). A factorial design included nine feeding treatments: three protein contents (50%, 40% or 30%) and three levels of replacement (0%, 25% or 45%) of FM protein by SBM protein. In addition, a commercial carp feed was used as reference. Final survival ranged from 98.2% to 99.4%. The 50% dietary protein with 0% or 25% replacement and 40% dietary protein with 25% replacement diets enabled higher growth (P < 0.05) and lower FCR (P < 0.05) than the rest of practical diets. Fish fed 50% dietary protein had similar growth than those fed carp feed (63.8% protein). Deformed fish averaged 1% for the practical diets and 87.6% for the carp feed. The basal practical diet has showed to be feasible and levels of 40–50% dietary protein with 25% replacement of FM protein by SBM protein can be recommended for juvenile tench aged 5–8 months.  相似文献   

Functionality of Agave Bagasse as Supplement for the Development of Prebiotics-Enriched Foods     

Escobedo-García  Sarai  Salas-Tovar  Jesús A.  Flores-Gallegos  Adriana C.  Contreras-Esquivel  Juan C.  González-Montemayor  Ángela M.  López  Mercedes G.  Rodríguez-Herrera  Raúl 《Plant foods for human nutrition (Dordrecht, Netherlands)》2020,75(1):96-102

Plant Foods for Human Nutrition - Agave bagasse is a fibrous-like material obtained during aguamiel extraction, which is also in contact with indigenous microbiota of agave plant during aguamiel...  相似文献   

Morphometric Relationship of Weight and Length of Cultured Freshwater Snail,Pomacea patula (Baker, 1922), at Three Different Life Stages     

Manuel García‐Ulloa  Maríadel Carmen Gallo‐García  Hervey Rodríguez‐González  Andrés Góngora‐Gómez  Jesús T. Ponce‐Palafox 《Journal of the World Aquaculture Society》2008,39(6):842-846

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Commercial Breakfast Cereals Available in Mexican Markets and their Contribution in Dietary Fiber, β-Glucans and Protein Quality by Rat Bioassays   总被引：1，自引：1，他引：0  

María R. Falcón-Villa  Jesús M. Barrón-Hoyos  Francisco J. Cinco-Moroyoqui 《Plant foods for human nutrition (Dordrecht, Netherlands)》2014,69(3):222-227

The beneficial effect of dietary fiber (DF) consumption has long been recognized. The global economy and open market trade policies have increased the availability of food products in Mexican markets, resulting in a wide variety of ready-to-eat commercial breakfast cereals classified as ‘high fiber’. This research was aimed to evaluate the total dietary fiber contents, its fractions (soluble and insoluble) and β-glucan in 13 commercial ‘high-fiber’ breakfast cereals, as well as to evaluate their protein quality by rat bioassays. Commercial ‘high-fiber’ breakfast cereals had 7.42–39.82 % insoluble dietary fiber, 2.53–12.85 % soluble dietary fiber, and 0.45–4.96 % β-glucan. These ready-to-eat commercial ‘high-fiber’ breakfast cereals differed significantly in their total dietary fiber, their soluble and insoluble DF fractions, and also in their β-glucan contents. When supplied as experimental diets, in 14-day rat feeding trials, the ‘high-fiber’ breakfast cereals showed an adverse effect on the % N digestibility but protein utilization, as measured as net protein ratio (NPR), was not significantly affected. The consumption of these commercial breakfast cereals, especially those made of oats as the basic ingredient, is highly recommended, since these products, being a concentrated source of dietary fiber, do not affect their protein quality.  相似文献