Home About us Contact
|
Home About us Contact | ||
|
|
||
Yeast Culture (yeast + culture)
Selected AbstractsThe Effects of Dietary Yeast Culture or Short-chain Fructo-oligosaccharides on the Intestinal Autochthonous Bacterial Communities in Juvenile Hybrid Tilapia, Oreochromis niloticus,×Oreochromis aureus,JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2009Zhi-Gang Zhou The effects of dietary yeast culture (YC) or short-chain fructo-oligosaccharides (FOS) on intestinal autochthonous bacterial communities in juvenile hybrid tilapia, Oreochromis niloticus,×Oreochromis aureus, were studied by 16S rDNA denaturing gradient gel electrophoresis (DGGE). Ninety Tilapias in tanks (10 fish per tank) were randomly and equally divided into three groups. At the end of an 8-wk feeding period of CK (the control treatment), YC (3 g/kg), or FOS (1 g/kg), autochthonous gut bacteria were analyzed in intestinal samples of all fish in each tank of a recirculating aquaculture system. The clear differences in the banding patterns indicated the obvious effects of dietary prebiotics on intestinal communities in hybrid tilapia. Higher variation was detected within the dietary YC group. This difference might be due to the effects of certain immune-stimulating agents in YC on the immunity response of hybrid tilapia. It was concluded that dietary prebiotics, YC, and FOS obviously affected the intestinal bacterial community in hybrid tilapia with different patterns for different kinds. [source] Yeast responses to stresses associated with industrial brewery handlingFEMS MICROBIOLOGY REVIEWS, Issue 5 2007Brian R. Gibson Abstract During brewery handling, production strains of yeast must respond to fluctuations in dissolved oxygen concentration, pH, osmolarity, ethanol concentration, nutrient supply and temperature. Fermentation performance of brewing yeast strains is dependent on their ability to adapt to these changes, particularly during batch brewery fermentation which involves the recycling (repitching) of a single yeast culture (slurry) over a number of fermentations (generations). Modern practices, such as the use of high-gravity worts and preparation of dried yeast for use as an inoculum, have increased the magnitude of the stresses to which the cell is subjected. The ability of yeast to respond effectively to these conditions is essential not only for beer production but also for maintaining the fermentation fitness of yeast for use in subsequent fermentations. During brewery handling, cells inhabit a complex environment and our understanding of stress responses under such conditions is limited. The advent of techniques capable of determining genomic and proteomic changes within the cell is likely vastly to improve our knowledge of yeast stress responses during industrial brewery handling. [source] MINIREVIEW: On the use of metaphor to understand, explain, or rationalize redundant genes in yeastFEMS YEAST RESEARCH, Issue 3 2008Stephen Cooper Abstract The proposal that yeast, and cells in general, contains redundant genes that enable cells to survive mutational change has been supported by experiments and a strong metaphor. The redundant gene proposal is analyzed, and it is noted that there are many problems with the redundant gene model. An alternative metaphor is suggested to explain the genetic composition of a yeast culture. [source] Effect of different liquid cultures of live yeast strains on performance, ruminal fermentation and microbial protein synthesis in lambsJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 6 2008M. K. Tripathi Summary Three yeast strains, Kluyveromyces marximanus NRRL-3234 (KM), Saccharomyces cerevisiae NCDC-42 (SC) and Saccharomyces uvarum ATCC-9080 (SU), and a mixed culture (1:1:1 ratio) were evaluated for their value as probiotics in lamb feeding in two experiment. In experiment I and II, 20 and 30 pre-weaner lambs were fed for 63 and 60 days in two and three equal groups respectively. All lambs were offered ad libitum a creep mixture and Zizyphus nummularia leaves, and yeasts were dosed orally. In experiment I, one group received no yeast, the other of the mixed culture (1.5,2 × 1010 live cells/ml). In experiment II, yeast cultivation was modified yielding 1.5,2 × 1013 live cells/ml. Lambs of the three experimental groups received 1 ml/kg live weight of one of the individual yeasts. Feed intake did not differ among groups of both experiments with the exception of SC-supplemented lambs in experiment II which showed a trend to higher intakes per kg metabolic body weight and in percentage of body weight when compared with KM- and SU-supplemented lambs. Supplementation of the mixed yeast culture had no effect on intakes of digestible crude protein and metabolisable energy, nutrient digestibility, nitrogen balance and rumen fermentation characteristics (pH, ammonia, volatile fatty acid concentration, protozoa count) and urinary allantoin as an indicator of microbial protein synthesis. The same was true for comparisons in experiment II except ciliate protozoa counts, which showed a trend to be the highest with SU and the lowest with SC. The results of present study show that the response of lambs to supplemented live yeast cultures is inconsistent, as it lacked to have an effect in the present study, and that differences among strains were small, even when supplemented at a much higher live cell count. [source] Effect of supplemental yeast culture and sodium bicarbonate on ruminal fermentation and blood variables in ramsJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 11-12 2006Nurten Gal Summary A trial was conducted to evaluate the effect of sodium bicarbonate (BC) and Saccharomyces cerevisiae, live yeast culture (yea sacc1026, YS) on ruminal fermentation and blood variables. Four Kivircik rams with ruminal cannula were used in a Latin square design, during 27-day periods (20 days for adaptation and 7 days for collection). They received 0 (control group), 5 g/day (i.e. 25 × 109 CFU) of YS or 10 g/day of sodium BC or 10 g/day of BC and 5 g/day of YS (BC + YS) (treatment groups). The cultures and sodium BC were added to the ration in a grain mix. The ration consisted of 70% grain mix and 30% lucerne hay. Rumen contents were collected before and 3 h and 6 h after morning feeding on days 1 and 7 in each collection period and were analyzed. Blood samples were also collected on the same days. Ruminal pH at 3 h (p , 0.1) and 6 h (p , 0.05) after feeding were higher when rams were fed BC and BC + YS than when they were fed CG and YS. Addition of YS to the diet did not modify the proportions of the different protozoa types; only Diplodinium at 0 h tended to be lower (p < 0.1) when rams were fed YS, BC and BC + YS than when they were fed CG. Plasma sodium value decreased by YS and BC + YS. Other biochemical and haematological variables were not affected by treatments. Also total volatile fatty acid, NH3 -N concentrations and protozoa counts in the ruminal fluid were not affected by treatments. [source] The Effects of Dietary Yeast Culture or Short-chain Fructo-oligosaccharides on the Intestinal Autochthonous Bacterial Communities in Juvenile Hybrid Tilapia, Oreochromis niloticus,×Oreochromis aureus,JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2009Zhi-Gang Zhou The effects of dietary yeast culture (YC) or short-chain fructo-oligosaccharides (FOS) on intestinal autochthonous bacterial communities in juvenile hybrid tilapia, Oreochromis niloticus,×Oreochromis aureus, were studied by 16S rDNA denaturing gradient gel electrophoresis (DGGE). Ninety Tilapias in tanks (10 fish per tank) were randomly and equally divided into three groups. At the end of an 8-wk feeding period of CK (the control treatment), YC (3 g/kg), or FOS (1 g/kg), autochthonous gut bacteria were analyzed in intestinal samples of all fish in each tank of a recirculating aquaculture system. The clear differences in the banding patterns indicated the obvious effects of dietary prebiotics on intestinal communities in hybrid tilapia. Higher variation was detected within the dietary YC group. This difference might be due to the effects of certain immune-stimulating agents in YC on the immunity response of hybrid tilapia. It was concluded that dietary prebiotics, YC, and FOS obviously affected the intestinal bacterial community in hybrid tilapia with different patterns for different kinds. [source] An evaluation of DVAqua®, a fully-fermented yeast culture, during long-term hatchery rearing of McConaughy strain rainbow troutAQUACULTURE NUTRITION, Issue 3 2010M.E. BARNES Abstract The addition of a proprietary, fully-fermented yeast Saccahromyces cerevisiae culture supplement (DVAqua®, Diamond V Mills, Cedar Rapids, IA, USA) was evaluated during long-term feeding of McConaughy strain rainbow trout Oncorhynchus mykiss. Beginning at initial feeding and continuing for 408 days of hatchery rearing, the trout received either a commercially-manufactured feed or the same feed containing 0.125 g kg,1 DVAqua. This study was conducted at a production level as part of normal (real-world) hatchery operations, with the fish periodically inventoried and moved into different rearing units. Although no rearing-tank replication occurred during the first 54 days of feeding, multiple tanks and raceways were used thereafter. Fish in rearing units receiving DVAqua supplementation exhibited less mortality, particularly during the earlier rearing stages. During the final 177 days of rearing in six raceways, DVAqua-fed McConaughy strain trout were significantly larger and had a significantly improved feed conversion ratio. The overall feed conversion ratio for the entire duration of the study was 1.17 in the fish receiving DVAqua supplementation compared to 1.21 in the control group. Despite the limitations of this study, the use of DVAqua is recommended for McConaughy strain rainbow trout and other less-domesticated, more difficult-to-rear salmonids. [source] Effect of different liquid cultures of live yeast strains on performance, ruminal fermentation and microbial protein synthesis in lambsJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 6 2008M. K. Tripathi Summary Three yeast strains, Kluyveromyces marximanus NRRL-3234 (KM), Saccharomyces cerevisiae NCDC-42 (SC) and Saccharomyces uvarum ATCC-9080 (SU), and a mixed culture (1:1:1 ratio) were evaluated for their value as probiotics in lamb feeding in two experiment. In experiment I and II, 20 and 30 pre-weaner lambs were fed for 63 and 60 days in two and three equal groups respectively. All lambs were offered ad libitum a creep mixture and Zizyphus nummularia leaves, and yeasts were dosed orally. In experiment I, one group received no yeast, the other of the mixed culture (1.5,2 × 1010 live cells/ml). In experiment II, yeast cultivation was modified yielding 1.5,2 × 1013 live cells/ml. Lambs of the three experimental groups received 1 ml/kg live weight of one of the individual yeasts. Feed intake did not differ among groups of both experiments with the exception of SC-supplemented lambs in experiment II which showed a trend to higher intakes per kg metabolic body weight and in percentage of body weight when compared with KM- and SU-supplemented lambs. Supplementation of the mixed yeast culture had no effect on intakes of digestible crude protein and metabolisable energy, nutrient digestibility, nitrogen balance and rumen fermentation characteristics (pH, ammonia, volatile fatty acid concentration, protozoa count) and urinary allantoin as an indicator of microbial protein synthesis. The same was true for comparisons in experiment II except ciliate protozoa counts, which showed a trend to be the highest with SU and the lowest with SC. The results of present study show that the response of lambs to supplemented live yeast cultures is inconsistent, as it lacked to have an effect in the present study, and that differences among strains were small, even when supplemented at a much higher live cell count. [source] Cell growth and Trametes versicolor laccase production in transformed Pichia pastoris cultured by solid-state or submerged fermentationsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2010Marcos López Abstract BACKGROUND: Growth kinetics of Pichia pastoris and heterologous expression of Trametes versicolor laccase were compared. This is the first study of its kind between solid-state yeast cultures done on polyurethane foam (PUF) and submerged liquid fermentations (SmF). RESULTS: The maximum values of biomass were similar for SSF (solid-state fermentation) and SmF experiments when the BOD (biochemical oxygen demand) was lower than 100 g L,1. For higher BOD levels, the maximum values of biomass were 55 g L,1 (SSF) and 35 g L,1 (SmF). Micrographs of PUF preparations showed yeast growing within liquid lamellae, thinner than 100 µm, forming large horizontal aggregates. Yeast aggregates were much smaller in SmF than in SSF experiments; however, laccase expression was lower in PUF than in SmF, unless the methanol concentration was increased to 63 g L,1, which was inhibitory only to the SmF system. CONCLUSION: The results show that oxygen mass transfer is more efficient in SSF, which is related to the higher area/volume ratio compared with SmF. Induction differences may also be due to hindered diffusion of methanol within large yeast aggregates. Copyright © 2009 Society of Chemical Industry [source] Application of pure and mixed probiotic lactic acid bacteria and yeast cultures for oat fermentationJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2005Associate Professor Dr Angel Angelov Abstract Fermentation of a prebiotic containing oat substrate with probiotic lactic acid bacteria and yeast strains is an intriguing approach for the development of new synbiotic functional products. This approach was applied in the present work by using pure and mixed microbial cultures to ferment a heat-treated oat mash. Results show that the strains studied were appropriate for oat fermentation and the process could be completed for 6,10 h depending on the strain. The viable cell counts achieved within this time were above the required levels of 106,107 cfu ml,1 for probiotic products. Both single lactic acid bacteria strains and mixed cultures of the same strains with yeast were found suitable for oat fermentation. However, the pure LAB cultures attributed better flavour and shelf life of the oat drinks. The content of the prebiotic oat component beta-glucan remained within 0.30,0.36% during fermentation and storage of the drinks obtained with each of the strains used. Thus, these products would contribute diet with the valuable functional properties of beta-glucan. Also, the viability of pure and mixed cultures in the oat products was good: levels of cell counts remained above the required numbers for probiotic products throughout the estimated shelf-life period. Copyright © 2005 Society of Chemical Industry [source] What is the role of the hevein-like domain of fruit class I chitinases in their allergenic capacity?CLINICAL & EXPERIMENTAL ALLERGY, Issue 3 2002A. Dìaz-Perales Background Class I chitinases are the major panallergens in fruits associated with the latex,fruit syndrome. These enzymes contain an N-terminal hevein-like domain homologous to latex hevein, and a larger catalytic domain. The role of these domains in their allergenic capacity is still controversial. Objective We sought to evaluate the role of both domains of class I chitinases in their IgE-binding properties, using Cas s 5, the major allergen from chestnut, as a model. Methods Recombinant Cas s 5 and its deleted form, lacking the hevein-like domain, designated rCat, were expressed in Pichia pastoris using the pPIC 9 vector. Both recombinant products were purified from the supernatants of transformed yeast cultures by gel-filtration and cation-exchange chromatography. The isolated proteins were characterized by N-terminal sequencing, enzymatic activity and N-glycosylation tests, anti-chitinase and specific IgE immunodetection. Immunoblot, RAST and CAP inhibition assays were also performed. Results Both purified rCas s 5 and rCat showed the expected N-terminal amino acid sequences and an enzymatic activity similar to that of their natural counterparts isolated from chestnut seeds, and were strongly recognized by anti-chitinase antibodies. In contrast, only rCas s 5, but not rCat, bound specific IgE from sera of patients suffering from the latex,fruit syndrome, and fully inhibited IgE-binding to natural Cas s 5 in immunoblot inhibition assays. Latex hevein also exerted a strong immunoblot inhibition of IgE-binding to chestnut Cas s 5. RAST and CAP inhibition using whole chestnut extract on the solid phase, rendered inhibition levels around 70,90% for rCas s 5 and 60% for rCat, in contrast to the immunoblotting results. Conclusions Recombinant Cas s 5 behaves like natural Cas s 5 in IgE-binding assays in vitro. The hevein-like domain of allergenic class I chitinases seems to include all their main IgE-binding epitopes when tested by immunodetection and immunoblot inhibition experiments. RAST and CAP inhibition assays, on the contrary, suggest that relevant epitopes are also harboured in the catalytic domain of these allergens. [source] | ||||||||||||||||