Control of the growth of Alicyclobacillus acidoterrestris in industrialized orange juice using rosemary essential oil and nisin

The use of rosemary essential oil (RO) and its combination with nisin (RO+N) in preventing the multiplication of Alicyclobacillus acidoterrestris in orange juice was evaluated. The minimum inhibitory and bactericidal concentrations (MIC and MBC) for RO were both 125 μg ml⁻¹ while RO+N displayed a synergistic effect. The use of RO and RO+N at concentrations of 1, 4 and 8× MIC in orange juice for 96 h was evaluated in terms of their sporicidal effectiveness. With regard to the action against A. acidoterrestris spores, RO at 8× MIC was sporostatic, whereas RO+N at 1× MIC was sporicidal. Morphological changes in the structure of the micro-organism after treatment were also observed by microscopy. Furthermore, flow cytometric analysis showed that most cells were damaged or killed after treatment. In general, the antioxidant activity after addition of RO+N decreased with time. The results demonstrate that using the combination of RO and nisin can prevent the A. acidoterrestris growth in orange juice.     

Optimizing purebred selection for crossbred performance using QTL with different degrees of dominance

A method was developed to optimize simultaneous selection for a quantitative trait with a known QTL within a male and a female line to maximize crossbred performance from a two-way cross. Strategies to maximize cumulative discounted response in crossbred performance over ten generations were derived by optimizing weights in an index of a QTL and phenotype. Strategies were compared to selection on purebred phenotype. Extra responses were limited for QTL with additive and partial dominance effects, but substantial for QTL with over-dominance, for which optimal QTL selection resulted in differential selection in male and female lines to increase the frequency of heterozygotes and polygenic responses. For over-dominant QTL, maximization of crossbred performance one generation at a time resulted in similar responses as optimization across all generations and simultaneous optimal selection in a male and female line resulted in greater response than optimal selection within a single line without crossbreeding. Results show that strategic use of information on over-dominant QTL can enhance crossbred performance without crossbred testing.     

Selecting high-dimensional mixed graphical models using minimal AIC or BIC forests

Background  

Chow and Liu showed that the maximum likelihood tree for multivariate discrete distributions may be found using a maximum weight spanning tree algorithm, for example Kruskal's algorithm. The efficiency of the algorithm makes it tractable for high-dimensional problems.     

Effect of postnatal development on calcium currents and slow charge movement in mammalian skeletal muscle

Single- (whole-cell patch) and two-electrode voltage-clamp techniques were used to measure transient (Ifast) and sustained (Islow) calcium currents, linear capacitance, and slow, voltage-dependent charge movements in freshly dissociated fibers of the flexor digitorum brevis (FDB) muscle of rats of various postnatal ages. Peak Ifast was largest in FDB fibers of neonatal (1-5 d) rats, having a magnitude in 10 mM external Ca of 1.4 +/- 0.9 pA/pF (mean +/- SD; current normalized by linear fiber capacitance). Peak Ifast was smaller in FDB fibers of older animals, and by approximately 3 wk postnatal, it was so small as to be unmeasurable. By contrast, the magnitudes of Islow and charge movement increased substantially during postnatal development. Peak Islow was 3.6 +/- 2.5 pA/pF in FDB fibers of 1-5-d rats and increased to 16.4 +/- 6.5 pA/pF in 45-50-d-old rats; for these same two age groups, Qmax, the total mobile charge measurable as charge movement, was 6.0 +/- 1.7 and 23.8 +/- 4.0 nC/microF, respectively. As both Islow and charge movement are thought to arise in the transverse-tubular system, linear capacitance normalized by the area of fiber surface was determined as an indirect measure of the membrane area of the t-system relative to that of the fiber surface. This parameter increased from 1.5 +/- 0.2 microF/cm2 in 2-d fibers to 2.9 +/- 0.4 microF/cm2 in 44-d fibers. The increases in peak Islow, Qmax, and normalized linear capacitance all had similar time courses. Although the function of Islow is unknown, the substantial postnatal increase in its magnitude suggests that it plays an important role in the physiology of skeletal muscle.     

Deconjugation of glucuronides catalysed by UDPglucuronyltransferase

Evidence was found for UDPglucuronyltransferase-catalysed deconjugation of p-nitrophenol-, 4-methylumbelliferone- and phenolphthalein-glucuronides. The evidence is based on the following observations: 1, deconjugation is UDP-dependent and the reactions show Michaels-Menten kinetics with respect to UDP and glucuronide saturability; 2, UDP-glucuronic acid was identified as reaction product; 3, all studies were done in the presence of a beta-glucuronidase inhibitor; 4, induction profiles, using 3-methylcholanthrene and phenobarbital as inducing agents, were identical for conjugation and deconjugation reactions. Optimal deconjugation rates for p-nitrophenol- and 4-methylumbelliferone-glucuronides were at pH 5.1 and for phenolphthalein-glucuronide at pH 6.5. Only conjugation reactions showed latency; the corresponding deconjugation reactions were not latent. UDPglucuronyltransferase is a group of oligomeric isoenzymes with different molecular masses. The molecular masses of the isoenzyme species catalysing the forward and reverse reactions were determined by radiation-inactivation analysis. The molecular masses of the isoenzyme species mediating the catalyses of deconjugation reactions were significantly smaller than those mediating catalyses of conjugation reactions: 66 +/- 4 kDa vs. 109 +/- 7 kDa for p-nitrophenol; 82 +/- 8 kDa vs. 105 +/- 6 kDa for 4-methylumbelliferone; and 74 +/- 8 kDa vs. 159 +/- 14 kDa for phenolphthalein. This suggests that for catalyses of deconjugation reactions only part of a UDPglucuronyltransferase isoenzyme is needed, whereas for forward reactions the complete isoenzymes are required.     

Morbidity in Chagas' disease. IV. Longitudinal study of 10 years in Pains and Iguatama, Minas Gerais, Brazil

An evolutive study of the "case-control" type was carried out in an endemic area of Chagas' disease in Minas Gerais State, Brazil, using two cross-section evaluations with an interval of ten years between them (1974-1984). Patients were paired for sex and age. In the first cross-section study 264 pairs one with a positive serology and the other with a negative serology for T. cruzi antibodies were included. In the second evaluation, ten years later, 235 patients among those with previous positive serology and 216 with negative serology were located, but only 110 pairs could be recomposed and reexamined (clinical examination, ECG and Rx of the heart and esophagus). The incidence of chagasic cardiopathy in the cases with positive serology but previously assymptomatic was 38.3% during the ten year period. On the other hand there was a deterioration in 24% of the patients with chagasic cardiopathy since the first examination. Considering all clinical forms of the disease in 34.5% of the patients the clinical situation deteriorated, in 57.3% there was no change and in 8.2% the situation improved. The general mortality in the period was 23% in the chagasic group and 10.6% in the control group, but the lethality by cardiopathy was 17% in chagasic group and only 23.3% in the control group. The mortality was twice as high in males than in females, mainly in the age group from 30 to 59 years.     

The importance of methylthio-IMP for methylmercaptopurine ribonucleoside (Me-MPR) cytotoxicity in Molt F4 human malignant T-lymphoblasts

The importance of methyl-thioIMP (Me-tIMP) formation for methylmercaptopurine ribonucleoside (Me-MPR) cytotoxicity was studied in Molt F4 cells. Cytotoxicity of Me-MPR is caused by Me-tIMP formation with concomitant inhibition of purine de novo synthesis. Inhibition of purine de novo synthesis resulted in decreased purine nucleotide levels and enhanced 5-phosphoribosyl-1-pyrophosphate (PRPP) levels, with concurrent increased pyrimidine nucleotide levels. The Me-tIMP concentration increased proportionally with the concentration of Me-MPR. High Me-tIMP concentration also caused inhibition of PRPP synthesis. Maximal accumulation of PRPP thus occurred at low Me-MPR concentrations. As little as 0.2 μM Me-MPR resulted already after 2 h in maximal inhibition of formation of adenine and guanine nucleotides, caused by inhibition of purine de novo synthesis by Me-tIMP. Under these circumstances increased intracellular PRPP concentrations could be demonstrated, resulting in increased levels of pyrimidine nucleotides. So, in Molt F4 cells, formation of Me-tIMP form Me-MPR results in cytotoxicity by inhibition of purine de novo synthesis.     

Pelvic visceral arteries of rabbits (Oryctolagus cuniculus)]

40 pelvic preparations of rabbits (oryctolagus cuniculus) were bilaterally studied by dissection under the stereomicroscope and angiography. The arterial pattern of the pelvis, i.e. origin and branching of the umbilical, urogenital and internal pudendal arteries (visceral branches), is described. The main characteristics observed are as follows: (1) The umbilical artery is permeable in adults and gives origin to the cranial vesical artery and a caudal branch that irrigates the pelvic urogenital organs and, eventually, the rectum, with six patterns of branching in both sexes. (2) Usually, the urogenital artery is the continuation of the visceral branch of the internal iliac artery. In 1 animal, unilaterally, it arises from the median sacral artery. In 12 animals (6 bilaterally and 6 unilaterally) the urogenital artery is absent. When present, it forms two branches, a cranial and a caudal one, that irrigate of the urogenital organs in both sexes. (3) The internal pudendal artery is the direct continuation of the internal iliac artery and gives to rise to some visceral branches that irrigate the penis, bulbourethral gland and rectum (with six patterns of branching) in males, and the vagina, clitoris and rectum (with three patterns of branching) in females.