Live Baker Research Articles

A survey of the specificity and mechanism of 1,6 hexanediol-induced disruption of nuclear transport

ABSTRACT Selective transport through the nuclear pore complex (NPC) depends on the dynamic binding of FG-repeat containing nucleoporins, the FG-nups, with each other and with Karyopherins (Kaps). Here, we assessed the specificity and mechanism by which the aliphatic alcohol 1,6-hexanediol (1,6HD) disrupts the permeability barrier of NPCs in live baker’s yeast cells. After a 10-minute exposure to 5% 1,6HD, no notable changes were observed in cell growth, cytosolic pH and ATP levels, or the appearance of organelles. However, effects on the cytoskeleton and Hsp104 were noted. 1,6HD clearly affected the NPC permeability barrier, allowing passive nuclear entry of a 177kDa reporter protein that is normally confined to the cytosol. Moreover, multiple Kaps were displaced from NPCs, and the displacement of Kap122-GFP correlated with the observed passive permeability changes. 1,6HD thus temporarily permeates NPCs, and in line with Kap-centric models, the mechanism includes the release of numerous Kaps from the NPCs.

Conversion of amino acids to aryl/heteroaryl ethanol metabolites using human CYP2D6-expressing live baker's yeast.

Different natural aromatic/heterocyclic l-amino acids were biotransformed into aryl/heteroaryl ethanol metabolites via oxidative deamination, decarboxylation and reduction cascades using live baker's yeast cells producing intracellular human CYP2D6 enzyme. Among the three yeast strains expressing 3 different CYP2D6 variants, CYP2D6(2) (i.e. CYP2D6 wild-type) provided the best result under neutral pH conditions at RT. We have successfully converted six natural amino acids into their corresponding alcohols, having one carbon atom less, with moderate yields. Some of the downstream products like tryptophol and tyrosol induced the pTrKB (Tropomyosin receptor kinase B) activation pattern similar to that of BDNF (brain-derived neurotrophic factor), thereby depicting potential antidepressant activity. Control experiments and molecular modelling studies revealed that this tandem bio-transformation probably happens via a pyruvate intermediate. This study establishes that CYP2D6-expressing live yeast cells can be a powerful tool for the enzymatic C-N, C-C bond cleavage of amino-acids.

PHYSIOLOGICAL RESPONSES AND LACTATIONAL PERFORMANCE OF FARAFRA AND SAIDI SHEEP AS AFFECTED BY SUPPLEMENTATION OF PROBIOTIC WITH NATURAL ANTIOXIDANTS

A total of 88 ewes were used in this study in two trails (44 per each trail) to investigate the effects of supplementation of probiotic abbreviated as (Effective Microorganisms with Medicinal Herbs-EMMH) on physiological responses during thermonuteral and heat stress conditions and milk yield of two local breeds (Farafra and Saidi). The studied probiotic consisted of mixed culture of two strains of fungi (Trichoderma reesei and Aspergillus oryzae) with dry live baker's yeast (Saccharomyces cervisiae) and the mixed culture was enriched with natural antioxidants of herbal medicine plants. In the first trail, 22 Farafra and 22 Saidi ewes were used during summer, along mating and pregnancy seasons until parturition. In the second trail, 22 Farafra and 22 Saidi ewes in late pregnancy were used. Ewes of every breed were divided homogonously into two equal groups (11 ewes per each). Group (I) fed basal diet (concentrate feed mixture + rice straw). Group (II) fed basal diet + 3 kg EMMH/ton. Reproductive traits were estrus duration, conception rate (%) and gestational period, number of lambs born, number of twins and birth weight was recorded. Thermal responses, gas exchange parameters and heat production measurement were determined during thermoneutral (comfort) conditions and during heat stress condition (after exposing animals to direct sun for 2 hours). Also, climatological data were recorded periodically. Daily and total milk yield were measured along the lactation season using lambs sucking technique. Body weight gain of suckling lambs, weaning weight and survival rate were recorded. Also, values of heamatocrit % (Ht), total protein (TP) sodium (Na), Potassium (K) and total antioxidant capacity (TAC) were determined in ewes. In thermonuteral conditions, EMMH supplemented group had significantly (P< 0.05) lower rectal temperature than control group in Farafra ewes. Whereas, in heat stress conditions, rectal and skin temperature significantly (P< 0.05) decreased in EMMH supplemented group in both breeds. Respiration rate was significantly (P< 0.05) lower in supplemented group than control in Farafra ewes only. Tidal volume was significantly (P< 0.05) higher in EMMH group. While, metabolic rate and heat production values were significantly (P< 0.05) decreased in EMMH supplemented group. Average body weight and body weight change of ewes significantly (P <0.05) improved by EMMH supplementation. Conception rate was improved in EMMH group compared to control in both breeds (90.9% vs. 72.7% in Farafra ewes) and (81.8 vs. 72.7% in Saidi ewes). Furthermore, average litter size per ewe, number of lambs born per group, number of twins born per group were improved by EMMH supplementation. Total milk yield, average daily milk yield per ewe, weaning weight and total gain of lambs were significantly (P<0.05) improved by EMMH supplementation in both breeds. Also, survival rate was improved in EMMH group in both breeds. Values of total protein concentration (TP) and total antioxidant capacity (TAC) was significantly (P <0.05) higher in EMMH supplemented group in both Farafra and Saidi. From the present results, it can be concluded that supplementation of EMMH probiotic had a favorable effect in improving physiological responses of animals during heat stress and can ameliorate the adverse effects of heat stress. Also, it led to improve lactational performance of ewes and the performance of their suckling lambs.

Effects of dietary live and heat-inactive baker's yeast on growth, gut health, and disease resistance of Nile tilapia under high rearing density.

In this study, the effects of baker's yeast as probiotics was evaluated in Nile tilapia reared at high density. Juvenile tilapia were distributed to tanks at high density (436fish/m(3)) and fed with basal diet (CK) or diets supplemented with live (LY) or heat-inactivated yeast (HIY). Another group of fish reared at low density (218fish/m(3)) and fed with basal diet was also included (LowCK). After 8 weeks of feeding, growth, feed utilization, gut microvilli morphology, digestive enzymes, and expressions of hsp70 and inflammation-related cytokines in the intestine were assessed. Intestinal microbiota was investigated using 16S rRNA gene pyrosequencing. Fish were challenged with Aeromonas hydrophila to evaluate disease resistance. High rearing density significantly decreased the growth, feed utilization, microvilli length, and disease resistance of fish (CK versus LowCK). Moreover, the intestinal hsp70 expression was increased in fish reared at high density, supporting a stress condition. Compared to CK group, supplementation of live yeast significantly increased gut microvilli length and trypsin activity, decreased intestinal hsp70 expression, and enhanced resistance of fish against A.hydrophila (reflected by reduced intestinal alkaline phosphatase activity 24h post infection). The gut microbiota was not markedly influenced by either rearing density or yeast supplementation. Heat-inactivated yeast (HIY) didn't display the beneficial effects observed in LY except an increase in gut trypsin activity, suggesting the importance of yeast viability and thus secretory metabolites of yeast. In conclusion, live baker's yeast may alleviate the negative effects induced by crowding stress, and has the potential to be used as probiotics for tilapia reared at high density.

Use of Live Baker's Yeast, Saccharomyces cerevisiae, in Practical Diet to Enhance the Growth Performance of Galilee Tilapia, Sarotherodon galilaeus (L.), and Its Resistance to Environmental Copper Toxicity

The potential use of dietary probiotics to enhance the growth and health of aquatic animals has recently attracted intensive attention. Therefore, this study was conducted to evaluate the growth response of Galilee tilapia, Sarotherodon galilaeus (L.), and its resistance to waterborne copper toxicity. Fish (2.5–3.3 g) were fed a diet containing either 0.0 or 10 g live yeast, Saccharomyces cerevisiae, for 6 wk. After the feeding trial, fish at both diets were exposed to 0.0 or 1 ppm Copper (Cu) for 24 h, or 5 ppm Cu for 1 h (T1, T2, or T3 for groups fed basal control diet and T4, T5, or T6 for groups fed yeast supplement). The growth‐promoting influences of baker's yeast were observed. Feed utilization was significantly improved, and the biochemical parameters such as serum glucose, lipids, and protein increased when fish were fed a yeast‐enriched diet. No significant dietary effects were observed on creatinine, aspartate amninotransferase, and alanine aminotransferase because of yeast supplementation. After Cu exposure, the different biochemical parameters and Cu residues were significantly affected by yeast supplement, Cu levels, postexposure time, and their interactions (P &lt; 0.05). Fish in all treatments biochemically recovered the effect of Cu toxicity within 4–8 days. The comparison of Cu residues in Cu‐treated groups, at the same times, revealed that yeast supplementation reduced Cu absorption and accumulation in fish body (P &lt; 0.05). The obtained results indicate that baker's yeast could be used for Galilee tilapia culture to improve its growth performance and its resistance against the waterborne Cu toxicity.

The Bake Shop Ghost (review)

Reviewed by: The Bake Shop Ghost Deborah Stevenson Ogburn, Jacqueline K. The Bake Shop Ghost; illus. by Marjorie Priceman. Houghton, 200532p ISBN 0-618-44557-9$16.00 Ad 7-10 yrs After sour-tempered Cora Lee Merriweather passes on, she haunts her old bakery, vandalizing her successors' attempts at successful pastry-making. When Annie Washington takes over the shop, however, she's determined to weather the ghost's worst, and she makes an agreement with the ghost: if Annie can make a cake that brings tears to Cora Lee's eyes, then the ghost will leave Annie to her work. Though Annie's repeated efforts don't meet the stated condition, they do net her some useful feedback from Cora Lee and allow the live baker to understand what the ghost really wants: a decorated birthday cake just for her. With its repeated enumerations of luscious baked goods, the story is tasty, and the warm ending (Annie makes Cora Lee a partner and adds her name to the shop's) is sweetly filling. The book is, however, seriously text-heavy for its light premise, and the hints of repetition that might have helped structure the flow are buried, so it's a rather long and floury trip to the conclusion. Priceman's watercolor-and-pencil art is a little flyaway as well, with compositions less well focused than usual, but there are still sizable helpings of entertainment to be derived from the battle between the petite, red-shirted Annie and the lanky and appropriately pale (drawn only in line, with no coloration) Cora Lee. You can't go too far wrong with a story involving succulent pastry, so this might work to leaven a ghostly readaloud or just to provide some literary frosting. Copyright © 2005 The Board of Trustees of the University of Illinois

The effects of cells on oxygen transfer in bioreactors: physical presence of cells as solid particles

Oxygen transfer into broths of non-respiring live baker's yeast was studied at different cell concentrations, agitation speeds and aeration rates. Under all the studied conditions, the physical presence of cells as solid particles was found to reduce the oxygen transfer rate. The effect of physical blockage by the less permeable cells accumulated near the bubble surface was dominant in the studied systems, while the hydrodynamic enhancement by the “snowball” effect (G.F. Andrews, J.P. Fonta, E. Marrotta and P. Stroeve, Chem. Eng. J., 29 (1980) B39–B46, B47–B55) was insignificant. The reduction in volumetric oxygen transfer coefficient k L a increased with cell concentration, but with decreasing marginal effect. Higher agitation speeds and the lower aeration rate used in the study (1 vs. 2 vvm), which produced smaller bubbles with higher cell capture efficiencies, were also found to promote the blocking effect of non-respiring cells.

Aggregation pheromone ofCarpophilus antiquus (Coleoptera: Nitidulidae) and kairomonal use ofC. lugubris pheromone byC. antiquus

Males ofCarpophilus antiquus Melsheimer (Coleoptera: Nitidulidae) emit an aggregation pheromone that was found to be a novel hydrocarbon, (3E,5E,7E,9E)-6,8-diethyl-4-methyl-3,5,7,9-dodecatetraene. A synthetic scheme and spectra (mass and proton NMR) are given for the compound. Beetles produced the pheromone when feeding on a variety of media, including the brewer's yeast-based artificial diet, fermenting whole-wheat bread dough, corn, and prunes; live baker's yeast was generally added to the food media. Males held individually produced, on average, 25 × more pheromone per beetle than males held in groups of 10 or more. Pheromone was not produced until males were at least 5 days old but was still detected from the oldest beetles tested (47 days). In field tests, the pheromone was attractive to both sexes ofC. antiquus, and it was synergized by food volatiles: A combination of pheromone and fermenting whole wheat dough attracted 2.5× more beetles than pheromone alone, but dough by itself was not significantly more attractive than the control. Semiochemical interactions were studied amongC. antiquus and two other sympatric species for which pheromones are known,C. lugubris Murray andC. freemani Dobson.C. antiquus responded readily to the pheromone ofC. lugubris, but all other interspecific responses to the pheromones were weak. In a sample of naturally infested corn ears, the presence ofC. antiquus was strongly associated with the presence ofC. lugubris, as would be expected if the pheromone ofC. lugubris serves as a kairomone forC. antiquus.

The effects of ascorbic acid sodium propionate on the relative viability of a mutant of Drosophila melanogaster.

Food shortage resulting from crowding is a direct cause of reduced relative viability of theebony11 mutant ofD. melanogaster and this in turn is a major factor in reduction of the frequency of thee11 gene in cage populations. Since some insects require ascorbic acid and someebony mutants have been reported deficient in it, and since some doubt exists as to the presence of ascorbic acid in the food supply, a test was made to determine whether mutant inviability could be oftset by ascorbic acid. Substitution of ascorbic acid for live baker's yeast showed that dietary ascorbic acid has no effect on the relative viability ofe11/e11 or on the total yield of F2 progeny, either with or without sodium propionate.