Effect of Selenium Nanoparticle Size on IL-6 Detection Sensitivity in a Lateral Flow Device

Sepsis is the body’s response to an infection. Existing diagnostic testing equipment is not available in primary care settings and requires long waiting times. Lateral flow devices (LFDs) could be employed in point-of-care (POC) settings for sepsis detection; however, they currently lack the required sensitivity. Herein, LFDs are constructed using 150–310 nm sized selenium nanoparticles (SeNPs) and are compared to commercial 40 nm gold nanoparticles (AuNPs) for the detection of the sepsis biomarker interleukin-6 (IL-6). Both 310 and 150 nm SeNPs reported a lower limit of detection (LOD) than 40 nm AuNPs (0.1 ng/mL compared to 1 ng/mL), although at the cost of test line visual intensity. This is to our knowledge the first use of larger SeNPs (>100 nm) in LFDs and the first comparison of the effect of the size of SeNPs on assay sensitivity in this context. The results herein demonstrate that large SeNPs are viable alternatives to existing commercial labels, with the potential for higher sensitivity than standard 40 nm AuNPs

Factors affecting the creaming of human milk

The creaming properties of human milk have not been widely studied to date, and a mechanism for this phenomenon is not known. Here, the natural creaming of human milk, as affected by temperature and pre-treatments, was studied using dynamic light-scattering. The creaming rate of human milk increased with temperature in the range 5 °C to 40 °C. Freezing human milk at –20 °C and thawing at room temperature had little influence on creaming. Compared with bovine milk, human milk showed a faster creaming rate at 40 °C, but a slower rate at 5 °C, suggesting a lack of cold agglutination; the mechanisms of creaming were also shown to differ in response to heat treatment. This study expands the current knowledge on milk creaming, and may have potential application to storage and handling of human milk in hospitals or homes, therefore supporting optimal nutrition of infants

Effect of Protein Genotypes on Physicochemical Properties and Protein Functionality of Bovine Milk: A Review

Milk protein comprises caseins (CNs) and whey proteins, each of which has different genetic variants. Several studies have reported the frequencies of these genetic variants and the effects of variants on milk physicochemical properties and functionality. For example, the C variant and the BC haplotype of αS1-casein (αS1-CN), β-casein (β-CN) B and A1 variants, and κ-casein (κ-CN) B variant, are favourable for rennet coagulation, as well as the B variant of β-lactoglobulin (β-lg). κ-CN is reported to be the only protein influencing acid gel formation, with the AA variant contributing to a firmer acid curd. For heat stability, κ-CN B variant improves the heat resistance of milk at natural pH, and the order of heat stability between phenotypes is BB > AB > AA. The A2 variant of β-CN is more efficient in emulsion formation, but the emulsion stability is lower than the A1 and B variants. Foaming properties of milk with β-lg variant B are better than A, but the differences between β-CN A1 and A2 variants are controversial. Genetic variants of milk proteins also influence milk yield, composition, quality and processability; thus, study of such relationships offers guidance for the selection of targeted genetic variants

Proteomic Comparison of Equine and Bovine Milks on Renneting

Rennet-induced coagulation of bovine milk is a complex mechanism in which chymosin specifically hydrolyzes kappa-casein, the protein responsible for the stability of the casein micelle. In equine milk, this mechanism is still unclear, and the protein targets of chymosin are unknown. To reveal the proteins involved, the rennetability of equine milk by calf chymosin was examined using gel free and gel based proteomic analysis and compared to bovine milk RP-HPLC analysis of bovine and equine milks showed the release of several peptides following chymosin incubation. The hydrolyses of equine and bovine casein by chymosin were different, and the major peptides produced from equine milk were identified by mass spectrometry as fragments of beta-casein. Using two-dimensional electrophoresis, equine beta-casein was confirmed as the main target of calf chymosin over 24 h at 30 degrees C and pH 6.5. The gel based analysis of equine milk discriminated between the different individual proteins and provided information on the range of isoforms of each protein as a result of post translational modifications, as well as positively identified for the first time several isoforms of kappa-casein. In comparison to bovine milk, kappa-casein isoforms in equine milk were not involved in chymosin-induced coagulation. The intensity of equine beta-casein spots decreased following chymosin addition, but at a slower rate than bovine kappa-casein

A longitudinal study of fatty acid profiles, macronutrient levels, and plasmin activity in human milk

IntroductionHuman milk provides nutrients essential for infant growth and health, levels of which are dynamic during lactation.MethodsIn this study, changes in macronutrients, fatty acids, and plasmin activities over the first six months of lactation in term milk were studied.ResultsThere was a significant influence of lactation stage on levels of protein and plasmin activities, but not on levels of fat and carbohydrate in term milk. Concerning fatty acids in term milk, levels of caproic acid and α-linolenic acid increased significantly (p < 0.05), whereas those of arachidonic acid and docosahexaenoic acid decreased, in the six months after birth. Significant impacts of maternal pre-pregnancy BMI and infant gender on fatty acid profiles were also found. Multivariate statistical analysis showed that protein level, plasmin activity, and several fatty acids (α-linolenic acid, lignoceric acid, and docasadienoic acid) contributed strongly to discrimination of milk from different lactational stages.DiscussionThe study demonstrates that not all but some fatty acids were influenced by lactation, whereas protein and protease levels showed clear decreasing trends during lactation, which may help in understanding the nutritional requirements of infants