Inhibition of microbial cholesterol oxidases by dimethylmorpholines

Cholesterol oxidase is a potentially important enzyme in steroid transformations, catalysing the conversion of 3-hydroxy-5-ene steroids to 3-keto-4-ene derivatives via a 3-keto-5-ene intermediate. Morpholine derivatives, especially fenpropimorph and tridemorph, were found to block selectively the isomerisation activity of cholesterol oxidases isolated from Nocardia erythropolis, Streptomyces sp., Pseudomonas testosteroni and Schizophyllum commune. These enzymes differ strongly in physical characteristics and catalytic behaviour. The effectiveness of the inhibitors varied with the cholesterol oxidase tested. Fenpropimorph was most effective with each of the 4 enzymes, 50 mg/l inhibiting about 50% of the enzyme activity. Inhibition was instantaneous and followed a reversible competitive mechanism in Streptomyces sp. and a reversible non-competitive mechanism in Nocardia erythropolis and Schizophyllum commune. An irreversible type of inhibition was observed for P. testosteroni cholesterol oxidase.     

Biotechniques for air pollution control

This paper gives an overview of present biological techniques for the treatment of off-gases and the techniques that are being developed at the moment. The characteristics, advantages, disadvantages, costs and application area are discussed and compared. Biological off-gas treatment is based on the absorption of volatile contaminants in an aqueous phase or biofilm followed by oxidation by the action of microorganisms. Biofilters, bioscrubbers and biotrickling filters are used for elimination of odour and bioconvertable volatile organic and inorganic compounds and are enjoying increasing popularity. This popularity is a result of the low investment and operational costs involved compared to physico-chemical techniques and the elimination efficiencies that can be obtained. The operational envelop is still extending to higher concentrations and gas flow rates (exceeding 200,000 m³ h^–1) and a broader spectrum of degradable compounds. Research and development on the use of membranes and the addition of activated carbon or a second liquid phase to the biological systems may lead to a more efficient elimination of hydrophobic compounds and buffering of fluctuating loads. Shorter adaptation periods can be obtained by inoculation with specialized microorganisms. Improved design and operation are made possible by the growing insights in the kinetics and microbiology and supported by the development of models describing biological off-gas treatment. In conclusion, biotechniques are efficient and cost effective in treating off-gases with concentrations of biodegradable contaminants up to 1–5 g/m³. They could play a justified and important role in air pollution control in the coming years.Abbreviations VOC volatile organic compound - NO _x gaseous oxides of nitrogen     

Relationship between ultrasonic characteristics of the corpus luteum, plasma progesterone concentration and early pregnancy diagnosis in Friesian mares

The purpose of the present study was to evaluate the change in cross-sectional area of the early corpus luteum (CL) and progesterone production in relation to subsequent pregnancy diagnosis. The cross-sectional area of the CL of 75 Friesian brood mares was measured by ultrasonography on Day 1 or 2 and Day 8 or 9 after ovulation. The change in cross-sectional area was expressed in a volume ratio. Plasma progesterone concentrations were measured on Days 8 to 9, and ultrasonography to determine pregnancy status was carried out on Day 17. The data obtained were analyzed by using a multiple logistic regression model. There were significant differences in the age, volume ratio and progesterone concentration between pregnant and nonpregnant mares. Pregnancy on Day 17 was related to the change in size of the CL up to Days 8 to 9 and progesterone concentration on Days 8 to 9. These differences between pregnant and nonpregnant mares might reflect the first luteal response to pregnancy.     

Enzyme activity of rat tibialis anterior muscle differs between treatment with triamcinolone and prednisolone and nutritional deprivation

The maximal activity of a selection of enzymes involved in muscle carbohydrate handling, citric acid cycle and fatty acyl beta-oxidation were studied after treatment with the fluorinated corticosteroid triamcinolone and compared to a similar treatment of the non-fluorinated corticosteroid prednisolone in an equipotent anti-inflammatory dose. Furthermore, because triamcinolone causes loss of body mass and muscle wasting, the effects of triamcinolone were investigated relative to a control group, with the same loss of body mass, due to nutritional deprivation. The study was performed in male Wistar rats in the following treatment groups: TR, triamcinolone treatment (0.25 mg x kg(-1) x day(-1) for 2 weeks), which resulted in a reduction of body mass (24%); ND, nutritional deprivation (30% of normal daily food intake for 2 weeks) resulting in a similar (24%) decrease of body mass as TR; PR, prednisolone treatment (0.31 mg x kg(-1) x day(-1) for 2 weeks), with a 10% increase in body mass; FF, free-fed control group, with a 12% increase in body mass in 2 weeks. Compared to FF, TR induced an increase in phosphofructokinase (PFK) activity (P < 0.01), glycogen synthase [GS(i + d)] activity (P < 0.05) and glycogen content (P < 0.01) in the tibialis anterior muscle. The PR and ND caused no alterations in PFK or citrate synthase (CS) activity compared to FF. Compared to PR, TR induced an increase in PFK (P < 0.01), CS (P < 0.05) and GS(i + d) activity (P < 0.01). Both TR and PR caused an increased muscle glycogen content, being more pronounced in TR (P < 0.05). Compared to ND, TR induced an increased CS (P < 0.05) and GS(i + d) activity (P < 0.01) and glycogen content (P < 0.01). The ND resulted in a decreased glycogen content compared to FF (P < 0.05). None of the treatments affected the activity of glycogen phosphorylase, beta-hydroxyacyl coenzyme A dehydrogenase and lactate dehydrogenase. It was concluded that corticosteroids led to an increased muscle glycogen content; however, the changes in the enzymes of carbohydrate metabolism were corticosteroid type specific and did not relate to undernutrition, which accompanied the triamcinolone treatment.     

Optimisation of oil red O staining permits combination with immunofluorescence and automated quantification of lipids

The objective of the present study was to develop a stain permitting automated quantification of myocellular lipid depositions in skeletal muscle sections together with immunolocalisation of other myocellular constituents by fluorescence microscopy. Lipid droplets were detected in skeletal muscle by oil red O (ORO). Conventional ORO was modified to diminish background staining, prevent crystallisation of ORO and to optimise lipid retention in cryosections. These modifications resulted in a punctate staining of lipid droplets, rather than the somewhat diffuse staining by conventional ORO. Small cavities in muscle sections (like the lumen of small blood vessels) lack ORO when using the protocol presented here. In addition a staining protocol is presented combining ORO with immunofluorescence. This combination permits multiple staining studies in the same section. Thus, lipid droplets can be studied together with immunolabelling of proteins involved in lipid handling and metabolism. This will extend our knowledge on the subcellular localisation of lipid handling proteins (i.e. enzymes and fatty acid transporting proteins) in relation to the localisation of lipid depositions. In conclusion, the protocol presented here permits examination of ORO-stained lipid droplets in skeletal muscle sections together with multiple staining of other immunodetectable proteins present in skeletal muscle by quantitative fluorescence microscopy.     

Reproductive performance of Friesian mares after retained placenta and manual removal of the placenta

Because the incidence of retained placenta in Friesian mares is estimated to be high, and no reports have been published on the reproductive performance of Friesian mares after retained placenta, we studied postpartum reproductive performance in Friesian brood mares with (n = 54) and without (n = 50) retained placenta. We defined a retained placenta as the failure to expel all fetal membranes within 3 h after the delivery of a foal. We subdivided the group of mares with retained placenta into mares in which the placenta had been removed manually (n = 30) and mares in which it had not (n = 24). Within each group, we compared reproductive performance after breeding in the foal heat and breeding in a subsequent heat. We also recorded the age of the mares, number of mares treated with antibiotics after insemination, and number of mares treated with prostaglandins. The interval between delivery and conception, efficacy rate (number of served cycles divided by the number of mares that had a positive pregnancy diagnosis), seasonal pregnancy rate, pregnancy rate after first insemination, pregnancy loss rate, and foaling rate did not differ between mares with and without retained placenta or between mares with and without manual removal of the retained placenta. Within each group, the pregnancy rate after first insemination did not differ between breeding for the first time in the foal heat and breeding for the first time in a subsequent heat. We concluded that reproductive performance did not differ between (1) Friesian mares with and without retained placenta and (2) Friesian mares with and without manual removal of the placenta. With regard to reproductive performance, retained placenta and manual removal of the placenta are not valid reasons to avoid foal heat breeding in Friesian mares.     

Unusual presentation of choriocarcinoma

Background  

Choriocarcinoma is an aggressive neoplasm arising in the body of the uterus. The disease normally spreads to lung and brain.     

Influence of prolonged endurance cycling and recovery diet on intramuscular triglyceride content in trained males

Intramuscular triglycerides (IMTG) are assumed to form an important substrate source during prolonged endurance exercise in trained males. This study investigated the effects of endurance exercise and recovery diet on IMTG content in vastus lateralis muscle. Nine male cyclists were provided with a standardized diet for 3 days, after which they performed a 3-h exercise trial at a 55% maximum workload. Before and immediately after exercise and after 24 and 48 h of recovery, magnetic resonance spectroscopy (MRS) was performed to quantitate IMTG content. Muscle biopsies were taken after 48 h of recovery to determine IMTG content by using quantitative fluorescence microscopy. The entire procedure was performed two times; in one trial, a normal diet containing 39% energy (En%) as fat was provided (NF) and in the other a typical carbohydrate-rich athlete's diet (LF: 24 En% fat) was provided. During exercise, IMTG content decreased by 21.4 +/- 3.1%. During recovery, IMTG content increased significantly in the NF trial only, reaching preexercise levels within 48 h. In accord with MRS, fluorescence microscopy showed significantly higher IMTG content in the NF compared with the LF trial, with differences restricted to the type I muscle fibers (2.1 +/- 0.2 vs. 1.4 +/- 0.2% area lipid staining, respectively). In conclusion, IMTG content in the vastus lateralis muscle declines significantly during prolonged endurance exercise in male cyclists. When a normal diet is used, IMTG contents are subsequently repleted within 48 h of postexercise recovery. In contrast, IMTG repletion is impaired substantially when a typical, carbohydrate-rich athlete's diet is used. Data obtained by quantitative fluorescence microscopy correspond well with MRS results, implying that both are valid methods to quantify IMTG content.     

Fabrication and Operation of a Nano-Optical Conveyor Belt

The technique of using focused laser beams to trap and exert forces on small particles has enabled many pivotal discoveries in the nanoscale biological and physical sciences over the past few decades. The progress made in this field invites further study of even smaller systems and at a larger scale, with tools that could be distributed more easily and made more widely available. Unfortunately, the fundamental laws of diffraction limit the minimum size of the focal spot of a laser beam, which makes particles smaller than a half-wavelength in diameter hard to trap and generally prevents an operator from discriminating between particles which are closer together than one half-wavelength. This precludes the optical manipulation of many closely-spaced nanoparticles and limits the resolution of optical-mechanical systems. Furthermore, manipulation using focused beams requires beam-forming or steering optics, which can be very bulky and expensive. To address these limitations in the system scalability of conventional optical trapping our lab has devised an alternative technique which utilizes near-field optics to move particles across a chip. Instead of focusing laser beams in the far-field, the optical near field of plasmonic resonators produces the necessary local optical intensity enhancement to overcome the restrictions of diffraction and manipulate particles at higher resolution. Closely-spaced resonators produce strong optical traps which can be addressed to mediate the hand-off of particles from one to the next in a conveyor-belt-like fashion. Here, we describe how to design and produce a conveyor belt using a gold surface patterned with plasmonic C-shaped resonators and how to operate it with polarized laser light to achieve super-resolution nanoparticle manipulation and transport. The nano-optical conveyor belt chip can be produced using lithography techniques and easily packaged and distributed.