Identification of Sc-type ILV6 as a target to reduce diacetyl formation in lager brewers' yeast.

Diacetyl causes an unwanted buttery off-flavor in lager beer. It is spontaneously generated from α-acetolactate, an intermediate of yeast's valine biosynthesis released during the main beer fermentation. Green lager beer has to undergo a maturation process lasting two to three weeks in order to reduce the diacetyl level below its taste-threshold. Therefore, a reduction of yeast's α-acetolactate/diacetyl formation without negatively affecting other brewing relevant traits has been a long-term demand of brewing industry. Previous attempts to reduce diacetyl production by either traditional approaches or rational genetic engineering had different shortcomings. Here, three lager yeast strains with marked differences in diacetyl production were studied with regard to gene copy numbers as well as mRNA abundances under conditions relevant to industrial brewing. Evaluation of data for the genes directly involved in the valine biosynthetic pathway revealed a low expression level of Sc-ILV6 as a potential molecular determinant for low diacetyl formation. This hypothesis was verified by disrupting the two copies of Sc-ILV6 in a commercially used lager brewers' yeast strain, which resulted in 65% reduction of diacetyl concentration in green beer. The Sc-ILV6 deletions did not have any perceptible impact on beer taste. To our knowledge, this has been the first study exploiting natural diversity of lager brewers' yeast strains for strain optimization.

Indications of cone beam CT in head and neck imaging in children.

For imaging of bony structures, especially for the anterior and lateral skull base in ORL medicine, cone beam computed tomography (CBCT) is an increasingly used alternative to CT, with a lower exposition to plain radiography that makes its use for imaging, particularly in children, very interesting. The aim of this study was to analyse possible indications and settings for CBCT in children and compare them to those of adults. A total of 554 patients (age range 0-18 years, mean age 10.36 years), who underwent CBCT between 01/2004-06/2013 in the ENT department at the university clinic of Marburg were enrolled in this retrospective analysis to evaluate technical parameters and indications. Data on CBCT of all children were compared with previously published data collected from 1730 adults who were diagnosed with the help of CBCT in the ENT department at the university clinic of Marburg, during the years 2012-2013. The most frequent indications of CBCT in children vs. adults were in the anterior skull base region: mid-facial trauma (60.4%) vs. chronic rhinosinusitis (54.8%), disturbed nasal breathing (13.9% vs. 13.0%) and chronic rhinosinusitis (12%) vs. mid-facial trauma (10.8%). For the lateral skull base the main indications were cholesteatoma (20.3%) vs. position control of cochlear implant (CI) electrode (31.2%), chronic otorrhoea (17.5%) vs. cholesteatoma (20.9%), and position control of CI electrode (11.8%) vs. chronic otitis media mesotympanalis (6.8%). CBCT is a suitable imaging modality for bony structures in adults and children. Settings mainly depend on the region of interest. One aim should also be to reduce exposure to radiation in both adults and children.

Induced ovulation and conception in locating sows.

Fifty lactating sows were injected with 1,500 IU pregnant mare serum gonadotrophin (PMSG) at an average of 25 days postpartum. Twenty-four of these sows received prostaglandin F2 alpha (PGF2 alpha) 24 hr prior to PMSG. Ninety-six hours after the PMSG injection, 1,000 IU of human chorionic gonadotrophin (HCG) were injected. Artificial insemination was performed at 24 and 36 to 42 hr post-HCG. The PMSG/HCG treatment resulted in pregnancy in 17 of 20 sows slaughtered from 34 to 43 days postbreeding and in 23 of 30 sows allowed to complete gestation. Mean numbers of corpora lutea (33) and viable embryos (15) were counted at slaughter. Litter sizes were averaged (11) for those sows allowed to farrow. Treatment with PGF2 alpha prior to PMSG injection had no effect on conception rates, number of corpora lutea, number of embryos or litter size in the lactating sows. In a second experiment, the same hormone treatments were administered to lactating sows beginning on day 5, 10, 15 or 20 postpartum. Pregnancy rates were 0/10, 2/10, 8/10 and 6/10, respectively (P less than .05, chi-square). At slaughter (30 to 40 days postbreeding), corpora lutea and embryo numbers recorded from pregnant sows were 23.0, 9.5; 31.5, 15.3, and 28.0, 18.8, respectively, for the sows in the day 10, day 15 and day 20 groups. In a third experiment, sows were given PMSG-HCG as previously described on either day 5 (five sows) or day 10 (14 sows) postpartum. Laparotomy of these sows 2 to 5 days postbreeding revealed minimal ovarian responsiveness at day 5, but 43% of the animals responded with multiple ovulations at day 10. The low pregnancy rate seen at day 10 in Exp. 2 may reflect embryonic mortality due to unfavorable uterine environment. We conclude that the PMSG/HCG treatment followed by timed artificial insemination of lactating sows will induce ovulation and coneption as early as 15 days postfarrowing. Pregnancy is thus concurrent with lactation, eliminating the need for early weaning and reducing the interval between successive farrowings.

Posttesticular surface modifications and contributions of reproductive tract fluids to the surface polypeptide composition of boar spermatozoa.

Caput and cauda epididymal fluids were found to be exceedingly rich in the numbers and kinds of polypeptides when analyzed by two-dimensional (2-D) gel electrophoresis. Only a few of the major (Coomassie-stained) and minor (silver-stained) epididymal fluid polypeptides were identified on epididymal sperm plasma membranes (PM) and even fewer identified in ejaculated sperm. The 2-D electrophoretic patterns of caput sperm PM differed little from those of cauda sperm PM. Thus, epididymal transit resulted in relatively minor quantitative and qualitative modifications in sperm PM composition. Seminal plasma showed a few major polypeptides from the cauda epididymal fluid, but the major constituents were those polypeptides from the seminal vesicle secretions. Sperm appear to acquire one acidic high molecular weight polypeptide from either the bulbourethral gland or prostate gland, and another major acidic polypeptide of high molecular weight from the seminal vesicle gland. Numerous neutral and basic low molecular weight polypeptides, originating from the seminal vesicles, adhered tightly to sperm. These were major polypeptides and constituted a substantial percentage of the total PM protein. Thus, major contributions to the sperm PM polypeptide profile occurred at ejaculation. This study did not address loosely bound polypeptides but is the first to analyze, in a comprehensive way, the origins of tightly bound sperm polypeptides from a single species.