Influence of a probiotic adjunct culture of Enterococcus faecium on the quality of cheddar cheese

Cheddar cheese has previously been shown to be an effective vehicle for delivery of viable cells of a probiotic Enterococcus faecium strain to the gastrointestinal tract. The particular strain, E. faecium PR88, has proven efficacy in the treatment of irritable bowel syndrome, and in this study it was evaluated for suitability as a starter adjunct for Cheddar cheese manufacture. When added to cheesemilk at an inoculum of 2 x 10(7) cfu/mL, the enterococcal adjunct maintained viability in Cheddar cheese at levels of up to 3 x 10(8) cfu/g during 9 months of ripening. Increased proteolysis and higher levels of some odor-active volatile compounds were observed in Cheddar cheeses containing the PR88 adjunct compared with the control throughout the ripening period. In addition, the enterococcal adjunct strain did not affect cheese composition. Although sensory evaluation showed no significant difference in flavor/aroma and body/texture scores between control and experimental cheeses, repeated comments by the commercial grader consistently described the cheeses containing PR88 as 'more advanced than the control' and as having 'better flavor'. These findings indicate that the presence of the PR88 adjunct strain in Cheddar cheese at levels of >/=10(8) cfu/g may positively influence Cheddar flavor.     

Cattle, ethanol, and biogas: Does closing the loop make economic sense?

The recent surge in US ethanol production has led to an increase in the amount of byproduct feed available to cattle producers. The impetus behind the increase in ethanol production is US policy to increase the production and use of renewable fuels. Manure from cattle production can also be used to produce a renewable fuel: methane. By co-locating a cattle feedlot with an existing ethanol plant, there may be synergies between ethanol, methane and cattle production. Byproduct from the ethanol plant can be fed to feeder cattle, manure from the cattle used in methane production, and the methane used as an energy source in the ethanol plant. Alternatively, methane can be used to generate electricity. We investigate the economic advisability of these systems. Using cost estimates for construction and operating a feedlot and anaerobic digester for methane production, we project revenues and costs over a 20-year time period. Our findings are consistent with studies that have considered just cattle production and methane production. The investment required to build a slatted-floor feedlot and concrete anaerobic digester cannot be justified under existing economic conditions. An increase in renewable fuel/electricity subsidies of at least $0.053 per kW h or $72 per 1000 m³ of methane are required to just break even when methane is used to produce electricity or is burned for thermal energy, respectively.     

Synergy of ethanol and putative neurotransmitters: glycine and serine

The putative neurotransmitters, glycine and serine, significantly enhanced the sleeping time (loss of the righting reflex) that was induced by ethanol in mice. The observed synergistic effect between ethanol and the amino acids is probably not related to an alteration of ethanol metabolism, but rather to an interaction of these compounds in the central nervous system.     

Aggregation of lysine-containing zeins into protein bodies in Xenopus oocytes

Zeins, the storage proteins of maize, are totally lacking in the essential amino acids lysine and tryptophan. Lysine codons and lysine- and tryptophan-encoding oligonucleotides were introduced at several positions into a 19-kilodalton zein complementary DNA by oligonucleotide-mediated mutagenesis. A 450-base pair open reading frame from a simian virus 40 (SV40) coat protein was also engineered into the zein coding region. Messenger RNAs for the modified zeins were synthesized in vitro with an SP6 RNA polymerase system and injected into Xenopus laevis oocytes. The modifications did not affect the translation, signal peptide cleavage, or stability of the zeins. The ability of the modified zeins to assemble into structures similar to maize protein bodies was assayed by two criteria: assembly into membrane-bound vesicles resistant to exogenously added protease, and ability to self-aggregate into dense structures. All of the modified zeins were membrane-bound; only the one containing a 17-kilodalton SV40 protein fragment was unable to aggregate. These findings suggest that it may be possible to create high-lysine corn by genetic engineering.     

Mitochondrial DNA mutation associated with Leber's hereditary optic neuropathy

Leber's hereditary optic neuropathy is a maternally inherited disease resulting in optic nerve degeneration and cardiac dysrhythmia. A mitochondrial DNA replacement mutation was identified that correlated with this disease in multiple families. This mutation converted a highly conserved arginine to a histidine at codon 340 in the NADH dehydrogenase subunit 4 gene and eliminated an Sfa NI site, thus providing a simple diagnostic test. This finding demonstrated that a nucleotide change in a mitochondrial DNA energy production gene can result in a neurological disease.     

Estrogen induces lipophosphoprotein in serum of male Xenopus laevis

Administration of estradiol 17beta to male Xenopus laevis induces the appearance in serum of large amounts of a serum lipophosphoprotein which is not readily removed from the circulation and which can be resolved from other serum components by chromatography on triethylaminoethyl-cellulose. The initial rate of production of serum lipophosphoprotein is independent of the amount of estrogen administered, but the maximum rate of production and the time taken to attain this rate are dose-dependent.     

Physical mapping of a translocation breakpoint in neurofibromatosis

The gene for von Recklinghausen neurofibromatosis (NF1), one of the most common autosomal-dominant disorders of humans, was recently mapped to chromosome 17 by linkage analysis. The identification of two NF1 patients with balanced translocations that involved chromosome 17q11.2 suggests that the disease can arise by gross rearrangement of the NF1 locus, and that the NF1 gene might be identified by cloning the region around these translocation breakpoints. To further define the region of these translocations, a series of chromosome 17 Not I-linking clones has been mapped to proximal 17q and studied by pulsed-field gel electrophoresis. One clone, 17L1 (D17S133), clearly identifies the breakpoint in an NF1 patient with a t(1;17) translocation. A 2.3-megabase pulsed-field map of this region was constructed and indicates that the NF1 breakpoint is only 10 to 240 kilobases away from 17L1. This finding prepares the way for the cloning of NF1.