Fibrolytic enzymes to increase the nutritive value of dairy feedstuffs

In vitro studies and a lactation trial were conducted to investigate the effects of fibrolytic enzyme mixtures at different inclusion amounts. Seven enzymes in amounts designed to mimic addition of 1, 5, 15, or 30 g/d to dairy diets were incubated in vitro with either soybean hulls or alfalfa for 24 or 48 h. Enzyme treatments generally increased in vitro dry matter disappearance (IVDMD), but not volatile fatty acid production. For some enzyme mixtures, lesser amounts of enzymes led to greater increases in IVDMD, whereas for others there were no differences among the amounts tested. The enzyme mixture with the most cellulase activity was the most effective enzyme in improving IVDMD. In additional in vitro experiments, the same enzymes were used at an amount of 5 g/d, as well as at other amounts that showed promising responses in the first trial. Preincubation of substrates with enzymes before fermentation also was tested. Alfalfa, soybean hulls, corn silage, and corn gluten feed were used as substrates. Preincubation of the substrate with enzymes for 18 h before in vitro fermentation improved IVDMD. The effect on substrate solubilization of incubating substrates with the enzymes but without rumen fluid was also studied. Addition of enzymes to substrates without subsequent fermentation did not solubilize significant amounts of dry matter, indicating that the positive effect of preincubation cannot be attributed directly to hydrolysis of substrates before the in vitro fermentation with ruminal microbes. The fibrolytic enzyme that appeared most promising in vitro did not affect lactational performance when fed to dairy cows.     

Interaction of erythrocytes with magnetic nanoparticles

Internalization of biocompatible magnetic nanoparticles by red blood cells (RBCs) is a key issue for opportunities of new applications in the biomedical field. In this study, we used in vitro tests to provide evidences of magnetic nanoparticle internalization by mice red blood cells. The internalization process depends upon the nanoparticle concentration and the nanoparticle hydrodynamic radii. The cell internalization of surface-coated maghemite nanoparticles was indirectly tracked by Raman spectroscopy and directly observed using transmission electron microscopy. The observation of nanoparticle cell uptaking using in vitro experiments represents an important breakthrough for the application of nanomagnetism in diagnosis and therapy of RBC-related diseases.     

用酸浸方法从化学动力活化的滑石中提取镁

从化学动力活化滑石样品中提取镁是在２９８Ｋ和３３３Ｋ温度下用浓度为０．５ｍｏｌ／ｄｍ＾３的Ｈ２ＳＯ４或ＨＣｌ溶液进行的。滑石在行星齿轮式球磨机中干磨约３０ｍｉｎ，使其以结晶形态转变无序状态，随着磨矿时间的延长，结构变化更大。这种结构变化意味着滑石结晶中镁周围的无离导致了镁的易提取和优选使用酸浸法。从滑石样品中提取镁用３０ｍｉｎ浸出时间是足够的，磨矿持续到３０ｍｉｎ时，镁的产率有效地提高到约４０％。     

Effect of anatomical location on the composition of fatty acids in double-muscled Belgian Blue cows

Double-muscled cows of the Belgian Blue breed, ranging from ca. 680 to 880 kg live weight were slaughtered and various fat depots sampled for lipid analysis. Subcutaneous fat (SCF), intermuscular fat in m. serratus (IMF1) and m. transversalis (IMF2), kidney fat (KF) and intramuscular fat in m. longissimus thoracis (IMF3) were sampled. In IMF3 samples, polar lipids were separated from other lipid classes by thin layer chromatography. Both the proportions (w w %) and gravimetric concentrations (mg g(-1) of sample) of long-chain fatty acids were determined in total lipids of SCF, IMF1, IMF2, KF and in lipid classes of IMF3 by gas chromatography. The greatest concentration of total fatty acids was found in KF (777.6 ± 82.6 mg g(-1)), followed by SCF (721.3 ± 92.2 mg g(-1)), IMF2 (709.8 ± 72.5 mg g(-1)) and IMF1 (682.1 ± 71.6 mg g(-1)). Triacylglycerol and polar lipid fatty acid content of m. longissimus thoracis (IMF3) were respectively 8.1 ± 3.3 and 3.1 ± 0.6 mg g(-1). Fatty acid content, particularly the triacylglycerol fatty acid content in IMF3, increased (p < 0.01) with increasing carcass fat content. Polar lipid fatty acids in IMF3 contained a higher proportion of polyunsaturated fatty acids (32.6 ± 4.8 %) and lower proportion of saturated fatty acids (27.4 ± 5.0%) compared to the triacylglycerol fatty acid fraction (p < 0.01), which may reflect a prerequisite for proper membrane functioning. Internal fat depots were more saturated (p < 0.01) compared to SCF. The proportion of monounsaturated fatty acids differed (p < 0.01) between IMF1 and IMF2, possibly reflecting differences in muscle activity and functioning. Oleic (C18:1) and stearic (C18:0) acids comprised more than 60% of the total fatty acids in all anatomical locations.     

Aspergillus spp., distribution, population composition and ochratoxin A production in wine producing vineyards in Greece

Vineyard surveys of 11 wine producing grape cultivars, were carried out in sixteen vineyards, in five winemaking regions in Greece, during 2002 and 2003. The occurrence of various Aspergillus spp. in bunches of berries at setting, veraison and ripening at harvest time was investigated. Aspergillus niger aggregate and A. carbonarius were predominantly isolated from sampled berries. Although the prevailing Aspergillus spp. isolates belonged to A. niger aggregate, isolates of A. carbonarius were the most efficient ochratoxin A (OTA) producers. Of 50 tested isolates of A. carbonarius 42% produced amounts of OTA, exceeding 25 ppb, while none of the 85 isolates of A. niger aggregate tested produced above 16 ppb.     

Linking quantitative exposure assessment and risk management using the food safety objective concept: an example with Listeria monocytogenes in different cross-contamination scenarios

A practical approach was used to achieve specified food safety objectives (FSOs) by incorporating risk assessment methodology. A series of cross-contamination scenarios at the retail level were evaluated in a spreadsheet and ranked according to their level of risk, and the degree to which they exceeded an FSO for Listeria monocytogenes (100 CFU/g) was determined. Percentiles and analyses of variance were used to identify which scenarios would be most likely not to achieve the FSO. It was also possible to incorporate into the model the effect of additional risk management interventions (e.g., hand washing method) by using "what if" scenarios analysis. The highest risk corresponded to the use of the same gloves to handle contaminated meat and then sliced ham compared with the safer method of using different gloves to handle each product. Nevertheless, in all scenarios bacterial concentrations could be higher than 10(8) CFU/g. A significant lack of knowledge regarding the transfer rates of L. monocytogenes was revealed, which provided the model with an important uncertainty component. The "what if" scenarios analysis based on the scenario representing handling food with bare hands followed by hand washing (scenario 2) revealed that the hand washing procedure had less impact than expected. This study illustrates the use of scenarios to model the most effective food processes and thus provide risk managers with appropriate information on which to base their decisions.     

Restoration and spectral recovery of mid-infrared chemical images

Fourier transform infrared (FTIR) microspectroscopy is a powerful technique for label-free chemical imaging that has supplied important chemical information about heterogeneous samples for many problems across a variety of disciplines. State-of-the-art synchrotron based infrared (IR) microspectrometers can yield high-resolution images, but are truly diffraction limited for only a small spectral range. Furthermore, a fundamental trade-off exists between the number of pixels, acquisition time and the signal-to-noise ratio, limiting the applicability of the technique. The recently commissioned infrared synchrotron beamline, infrared environmental imaging (IRENI), overcomes this trade off and delivers 4096-pixel diffraction limited IR images with high signal-to-noise ratio in under a minute. The spatial oversampling for all mid-IR wavelengths makes the IRENI data ideal for spatial image restoration techniques. Here, we measured and fitted wavelength-dependent point-spread-functions (PSFs) at IRENI for a 74× objective between the sample plane and detector. Noise-free wavelength-dependent theoretical PSFs are deconvoluted from images generated from narrow bandwidths (4 cm(-1)) over the entire mid-infrared range (4000-900 cm(-1)). The stack of restored images is used to reconstruct the spectra. Restored images of metallic test samples with features that are 2.5 μm and smaller are clearly improved in comparison to the raw data images for frequencies above 2000 cm(-1). Importantly, these spatial image restoration methods also work for samples with vibrational bands in the recorded mid-IR fingerprint region (900-1800 cm(-1)). Improved signal-to-noise spectra are reconstructed from the restored images as demonstrated for a mixture of spherical polystyrene beads in a polyurethane matrix. Finally, a freshly thawed retina tissue section is used to demonstrate the success of deconvolution achievable with a heterogeneous, irregularly shaped, biologically relevant sample with distinguishing spectroscopic features across the entire mid-IR spectral range.     

Innovative approach to investigating the microstructure of calcified tissues using specular reflectance Fourier transform-infrared microspectroscopy and discriminant analysis

Although bone fracture has become a serious global health issue, current clinical assessments of fracture risk based on bone mineral density are unable to accurately predict whether an individual is likely to suffer a fracture. There is increasing recognition that the chemical structure and composition, or microstructure, of mineralized tissues has an important role to play in determining the fracture resistance of bone. The objective of this preliminary study was to evaluate the use of specular reflectance Fourier transform infrared (SR FT-IR) microspectroscopy in conjunction with discriminant analysis as an innovative technique for providing future insights into the origins of orthopedic abnormalities. The impetus for this approach was that SR FT-IR microspectroscopy would offer several advantages over conventional transmission methods. Bone samples were obtained from young racehorses at known fracture predilection sites and spectra were successfully obtained from calcified cartilage and subchondral bone for the first time. By applying discriminant analysis to the spectral data set in biologically relevant regions, microstructural differences between groups of individuals were found to be related to features associated with both the mineral and organic components of the bone. The preliminary findings also suggest that differences in bone microstructure may exist between healthy individuals of the same age, raising important questions around the normal limits of individual variation and whether individuals may be predisposed to later fracture as a result of detrimental microstructural changes during early growth and development.