Search

Burn injury is a serious public health problem and scientists are continuously aiming to develop promising biomimetic dressings for effective burn wound management. In this study, a greater efficacy in burn wound healing and the associated mechanisms of a-lactalbumin (ALA) based electrospun nanofibrous scaffolds (ENs) as compared to other regenerative protein scaffolds were established. Bovine serum albumin (BSA), collagen type I (COL), lysozyme (LZM) and ALA were separately blended with poly(e-caprolactone) (PCL) to fabricate four different composite ENs (LZM/PCL, BSA/PCL, COL/PCL and ALA/PCL ENs). The hydrophilic composite scaffolds exhibited an enhanced wettability and variable mechanical properties. The ALA/PCL ENs demonstrated higher levels of fibroblast proliferation and adhesion than the other composite ENs. As compared to PCL ENs and other composite scaffolds, the ALA/PCL ENs also promoted a better maturity of the regenerative skin tissues and showed a comparable wound healing effect to Collagen sponge-R on third-degree burn model. The enhanced wound healing activity of ALA/PCL ENs compared to other ENs could be attributed to their ability to promote serotonin production at wound sites. Collectively, this investigation demonstrated that ALA is a unique protein with a greater potential for burn wound healing as compared to other regenerative proteins when loaded in the nanofibrous scaffolds. [ABSTRACT FROM AUTHOR]

Copyright of Nativa is the property of Revista Nativa and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The use of antioxidant-loaded protein-polysaccharide nanoparticle in stabilizing and delivering curcumin with high internal phase Pickering emulsions is comparatively scarce. Resveratrol (RES)-loaded α-lactalbumin (ALA)-chitosan (CHI) particles were fabricated and used for curcumin-loaded high internal phase Pickering emulsions (HIPPEs) stabilization and delivery. CLSM illustrated that RES-ALA-CHI nanoparticles were effectively adsorbed on oil/water (O/W) interface and a gel-like structure was formed surrounding oil droplets. All HIPPEs exhibited excellent physical stability. CUR retention was 75.4 % for HIPPEs with RES-ALA-CHI colloidal particles, which was appreciably higher than that with ALA-CHI colloidal particles (63.9 %) after 30 days storage. Compared to bulk medium-chain triglyceride (MCT), both lipolysis extent and curcumin (CUR) bioaccessibility were pronouncedly enhanced with HIPPEs-based delivery systems. But both HIPPEs (51.4 % and 43.7 %) exhibited lower extent of lipolysis than conventional emulsions (90.4 %). The occurrence of RES significantly restrained the lipolysis. These results demonstrated that HIPPEs could be excellent delivery systems for delivering lipophilic curcumin.

In epidemiological studies, cow's milk protein allergy (CMPA) is the most prevalent allergy for infants or young children. This study was conducted to compare the effect of Soummam and Saifi fermented milks on mice sensitized to whey protein (ß -Lactoglobulin and a -Lactalbumin). During 28 days, the animals from the first and second lot received via an oral way the fermented milks. In a second period of time, mice from the first, second lots were sensitized via intraperitoneal way using ß-Lg, mice from third and fourth lot were sensitized by a-Lactalbumin. The antigenecity was determined by enzyme-linked immunosorbent assay (ELISA). Symptom scores were determined after in vivo challenge with ß-Lg or a-Lac. Intestinal damage was evaluated by histological analysis. Analysis of the data revealed that the titers of anti-a-lactalbumin and anti-ß-lactoglbulin IgG increased significantly in the positive control groups given Soummam and Saifi fermented milk (p <0.001). Moreover, in fermented milk-treated mice, significant clinical symptoms were observed. Analysis of histological sections revealed that fermented milk doesn't reduce the microscopic lesions induced by ß-Lg or a-Lac sensitzation. This study indicated that the administration of Soummam fermented milk can modulate effectively the immune response and protect the intestinal epithelium integrity. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Bioprocess Engineering is the property of Chinese Journal of Bioprocess Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The whey proteins have acquired great importance due to their nutritional and technolo gical functionality. In the present review, we studied the use of Ultrafiltration (UF) applied to the separation of proteins and peptides from whey. It was found that the UF is one of the best alternatives. However, to achieve better results it is necessary to: accompany other membrane technologies (microfiltration, nanofiltration, electrodialysis, diafiltration), select the type of UF membrane to be used, and adjust the conditions of transmembrane pressure, pH and temperature. [ABSTRACT FROM AUTHOR]

Background: The diagnosis of IgE-mediated cow's milk allergy is often based on anamnesis, and on specific IgE (sIgE) levels and/or Skin Prick Tests (SPT), which have both a good sensitivity but a low specificity, often causing positive results in non-allergic subjects. Thus, oral food challenge is still the gold standard test for diagnosis, though being expensive, time-consuming and possibly at risk for severe allergic reactions. Aim: The aim of the present study was to perform a systematic review of the studies that have so far analyzed the positive predictive values for sIgE and SPT in the diagnosis of allergy to fresh and baked cow's milk according to age, and to identify possible cut-offs that may be useful in clinical practice. Methods: A comprehensive search on Medline via PubMed and Scopus was performed August 2017. Studies were included if they investigated possible sIgE and/or SPT cut-off values for cow's milk allergy diagnosis in pediatric patients. The quality of the studies was evaluated according to QUADAS-2 criteria. Results: The search produced 471 results on Scopus, and 2233 on PubMed. Thirty-one papers were included in the review and grouped according to patients' age, allergen type and cooking degree of the milk used for the oral food challenge. In children < 2 years, CMA diagnosis seems to be highly likely when sIgE to CM extract are ≥ 5 KUA/L or when SPT with commercial extract are above 6 mm or Prick by Prick (PbP) with fresh cow's milk are above 8 mm. Any cut-offs are proposed for single cow's milk proteins and for baked milk allergy in children younger than 2 years. In Children ≥ 2 years of age it is hard to define practical cut-offs for allergy to fresh and baked cow's milk. Cut-offs identified are heterogeneous. Conclusions: None of the cut-offs proposed in the literature can be used to definitely confirm cow's milk allergy diagnosis, either to fresh pasteurized or to baked milk. However, in children < 2 years, cut-offs for specific IgE or SPT seem to be more homogeneous and may be proposed. [ABSTRACT FROM AUTHOR]

lbumin sequence, with a frame shift of 1 amino acid between successive sequences, were synthesized on cellulose membranes using "SPOT" technology, and their binding to and inhibition of DPP-IV was studied. Among the 114 α-lactalbumin-derived decamers investigated, the peptides 60WCKDDQNPHS69 (αKi = 76 μM), 105LAHKALCSEK114 (Ki = 217 μM) and 110LCSEKLDQWL119 (Ki = 217 μM) were among the strongest DPP-IV inhibitors. While the SPOT- and traditionally-synthesized peptides showed consistent trends in DPP-IV inhibitory activity, the cellulose-bound peptides' binding behavior was not correlated to their ability to inhibit the enzyme. This research showed, for the first time, that peptide arrays are useful screening tools to identify DPP-IV inhibitory peptides from dietary proteins. [ABSTRACT FROM AUTHOR]

The complexes formed by partially folded human and bovine α-lactalbumin with oleic acid (OA) have been reported to display selective apoptotic activity against tumor cells. These complexes were named human (HAMLET) or bovine (BAMLET) alpha-lactalbumin made lethal to tumor cells. Here, we analyzed the OA complexes formed by fragments of bovine α-lactalbumin obtained by limited proteolysis of the protein. Specifically, the fragments investigated were 53–103 and the two-chain fragment species 1–40/53–123 and 1–40/104–123, these last being the N-terminal fragment 1–40 covalently linked via disulfide bridges to the C-terminal fragment 53–123 or 104–123. The OA complexes were obtained by mixing the fatty acid and the fragments in solution (10-fold and 15-fold molar excess of OA over protein fragment) or by chromatography of the fragments loaded onto an OA-conditioned anion exchange column and salt-induced elution of the OA complexes. Upon binding to OA, all fragments acquire an enhanced content of α-helical secondary structure. All OA complexes of the fragment species showed apoptotic activity for Jurkat tumor cells comparable to that displayed by the OA complex of the intact protein. We conclude that the entire sequence of the protein is not required to form an apoptotic OA complex, and we suggest that the apoptotic activity of a protein–OA complex does not imply specific binding of the protein. [ABSTRACT FROM AUTHOR]

The α-lactalbumin is a subunit of lactose-synthase, an enzyme responsible for lactose production, a disaccharide that influences milk production. Sequence variations of bovine α -lactalbumin have been associated with differences in milk yield. This study aimed to analyze allelic frequency differences at position - 1689 (g. A > G) and + 15 (g. A > G) of the α-lactalbumin gene in Holstein (Bos taurus) and Nellore (Bos indicus) cows. Blood samples were analyzed from 34 Holstein, 104 Nellore, and 99 Dairy Nellore cows using PCR-RFLP. The different RFLP patterns were sequenced and a novel sequence variation on nucleotide - 46 was identified. An adenine at this position was designated as the A allele and a guanine was designated B allele. The frequencies of alleles A - 1689, A - 46, and A + 15 differed between Holstein and both Nellore breeds. The results show that differences in α-lactalbumin allelic variants in the 5'-flanking and the 5'-UTR region might be associated with differences in milk production between Holstein cows and cows from Nellore breeds. However, the lack of difference between Nellore and Dairy Nellore suggests that other sequence variantions that regulate milk production might be responsible for the selection of Dairy Nellore cows with superior milk production. [ABSTRACT FROM AUTHOR]

HAMLET (Human α-lactalbumin Made Lethal to Tumor cells) triggers selective tumor cell death in vitro and limits tumor progression in vivo. Dying cells show features of apoptosis but it is not clear if the apoptotic response explains tumor cell death. This study examined the contribution of apoptosis to cell death in response to HAMLET. Apoptotic changes like caspase activation, phosphatidyl serine externalization, chromatin condensation were detected in HAMLET-treated tumor cells, but caspase inhibition or Bcl-2 over-expression did not prolong cell survival and the caspase response was Bcl-2 independent. HAMLET translocates to the nuclei and binds directly to chromatin, but the death response was unrelated to the p53 status of the tumor cells. p53 deletions or gain of function mutations did not influence the HAMLET sensitivity of tumor cells. Chromatin condensation was partly caspase dependent, but apoptosis-like marginalization of chromatin was also observed. The results show that tumor cell death in response to HAMLET is independent of caspases, p53 and Bcl-2 even though HAMLET activates an apoptotic response. The use of other cell death pathways allows HAMLET to successfully circumvent fundamental anti-apoptotic strategies that are present in many tumor cells. [ABSTRACT FROM AUTHOR]

Abstract: Variability in the protein composition of breast milk has been observed in many women and is believed to be due to natural variation of the human population. Single nucleotide polymorphisms (SNPs) are present throughout the entire human genome, but the impact of this variation on human milk composition and biological activity and infant nutrition and health is unclear. The goals of this study were to characterize a variant of human ¿-lactalbumin observed in milk from a Filipino population by determining the location of the polymorphism in the amino acid and genomic sequences of ¿-lactalbumin. Milk and blood samples were collected from 20 Filipino women, and milk samples were collected from an additional 450 women from nine different countries. ¿-Lactalbumin concentration was measured by high-performance liquid chromatography (HPLC), and milk samples containing the variant form of the protein were identified with both HPLC and mass spectrometry (MS). The molecular weight of the variant form was measured by MS, and the location of the polymorphism was narrowed down by protein reduction, alkylation and trypsin digestion. Genomic DNA was isolated from whole blood, and the polymorphism location and subject genotype were determined by amplifying the entire coding sequence of human ¿-lactalbumin by PCR, followed by DNA sequencing. A variant form of ¿-lactalbumin was observed in HPLC chromatograms, and the difference in molecular weight was determined by MS (wild type=14,070 Da, variant=14,056 Da). Protein reduction and digestion narrowed the polymorphism between the 33rd and 77th amino acid of the protein. The genetic polymorphism was identified as adenine to guanine, which translates to a substitution from isoleucine to valine at amino acid 46. The frequency of variation was higher in milk from China, Japan and Philippines, which suggests that this polymorphism is most prevalent in Asia. There are SNPs in the genome for human milk proteins and their implications for protein bioactivity and infant nutrition need to be considered. [Copyright &y& Elsevier]

Chemical shift assignment is reported for the protein ubiquitin denatured in 8M urea at pH 2. The variations in 15N chemical shifts of three different proteins (ubiquitin, disulfide reduced, carboxymethylated lysozyme, all-Ala-α-lactalbumin), all without disulfides and denatured in 8M urea at pH 2 are compared to `random coil shifts' of small model peptides (Braun et al., 1994) and to the averaged native chemical shifts taken from the BMRB database. Both parameterizations show a remarkable agreement with the averaged measured 15N chemical shifts in the three denatured proteins. Detailed analysis of these experimental 15N chemical shifts provides an estimate of the influence of nearest neighbors and conformational preferences on the chemical shift and provides a direct means to identify non-random structural preferences in denatured proteins. [ABSTRACT FROM AUTHOR]