Unlocking the bioactivity of meat proteins: Comparison of meat and meat hydrolysate via simulated gastrointestinal digestion

Understanding the functional attributes of meat proteins is crucial for determining their nutritional benefits. Depending on the form in which meat proteins are available, the digestive process can release peptides which are valuable for nutrition and may also possess bioactive properties, affecting physiology. Liquid chromatography - mass spectrometry (LC-MS) was used to quantitatively compare the molecular peptide features (representing non-redundant peptides), during the different stages of a simulated gastrointestinal digestion process of a minimally processed powdered meat and its enzymatically produced hydrolysate. Results from a principal component analysis (PCA) indicated that the hydrolysate did not undergo extensive additional digestion whereas the powdered meat was digested both at the gastric and in the intestinal phases. Bioactive peptide sequence prediction identified the meat hydrolysate but not the meat powder as the only source of exact and partial bioactive matches in the angiotensin-I converting enzyme and dipeptidyl peptidase IV inhibition categories. Also, a higher source of cryptides (encrypted bioactive peptides), indicated that meat hydrolysates are potentially a better substrate for the release of these enzyme inhibitory peptides. These observations thus suggest that pre-digestion of a complex food matrix such as meat, may enhance its bioavailability following oral consumption early in the digestion process. SIGNIFICANCE: This work highlights enzymatic hydrolysis of meat proteins prior to ingestion allows for potentially higher bioavailability of bioactive peptides that inhibit angiotensin-I converting enzyme and dipeptidyl peptidase IV, thus possibly aiding high blood pressure and type 2 diabetes management.

Feeding Bugs to Bugs: Edible Insects Modify the Human Gut Microbiome in an in vitro Fermentation Model

We here report a study characterizing the potential for edible insects to act as a prebiotic by altering the bacterial composition of the human fecal microbiome, using batch cultures inoculated with fecal adult human donors. Black field cricket nymphs, grass grub larvae, and wax moth larvae were subjected to an in vitro digestion to simulate the oral, gastric, and small intestinal stages of digestion. The digested material was then dialyzed to remove small molecules such as amino acids and free sugars to simulate removal of nutrients through upper gastrointestinal tract digestion. The retentate, representing the digestion resistant constituents, was then fermented in fecal batch cultures for 4, 7, and 15 h to represent rapid and longer fermentation times. Batch cultures without any added substrates were also set up to act as controls. Additionally, phosphate-buffered saline was used as a no-protein control and milk powder as "standard" protein control. At the end of the incubation period, the bacterial pellets were collected for microbiome analysis by 16S rRNA gene amplicon sequencing. Analysis of fecal cultures showed striking differences in community composition. Each substrate led to significant differences across a wide range of taxa compared to each other and PBS controls. Among the differences observed, digested grass grub larvae increased proportions of Faecalibacterium and the Prevotella 2 group. Black field crickets increased the prevalence of the Escherichia-Shigella group, Dialister genus, and a group of unclassified Lachnospiraceae. Wax moth larvae promoted the expansion of the same group of unclassified Lachnospiraceae and the Escherichia/Shigella group. The increased Faecalibacterium observed in the cultures with grass grub larvae represents a noteworthy finding as this bacterium is widely thought to be beneficial in nature, with demonstrated anti-inflammatory properties and associations with gut health. We conclude that insects can differentially modulate the microbiome composition in batch cultures inoculated with adult fecal material after simulated in vitro digestion. Although the physiological impact in vivo remains to be determined, this study provides sound scientific evidence that investigating the potential for consuming insects for gut health is warranted.

Comparative analysis of human milk and infant formula derived peptides following in vitro digestion

It has long been recognised that there are differences between human milk and infant formulas which lead to differences in health and nutrition for the neonate. In this study we examine and compare the peptide profile of human milk and an exemplar infant formula. The study identifies both similarities and differences in the endogenous and postdigestion peptide profiles of human milk and infant formula. This includes differences in the protein source of these peptides but also with the region within the protein producing the dominant proteins. Clustering of similar peptides around regions of high sequence identity and known bioactivity was also observed. Together the data may explain some of the functional differences between human milk and infant formula, while identifying some aspects of conserved function between bovine and human milks which contribute to the effectiveness of modern infant formula as a substitute for human milk.

Proteomic and peptidomic differences and similarities between four muscle types from New Zealand raised Angus steers

Four muscles from New Zealand-raised Angus steers were evaluated (musculus semitendinosus, m. longissimus thoracis et lumborum, m. psoas major and m. infraspinatus) to test their differences and common features in protein and peptide abundances. The ultimate goal of such a comparison is to match muscle types to products with targeted properties. Protein profiling based on two-dimensional electrophoresis showed that the overall profiles were similar, but, between muscle types, significant (p<0.05) intensity differences were observed in twenty four protein spots. Profiling of endogenous peptides allowed characterisation of 346 peptides. Quantitative analysis showed a clear distinction between the muscle types. Forty-four peptides were identified that showed a statistically significant (p<0.05) and substantial (>2-fold change) difference between at least two muscle types. These analyses demonstrate substantial similarities between these four muscle types, but also clear distinctions in their profiles; specifically a 25% difference between at least two muscles at the peptidomic level, and a 14% difference at the proteomic level.

The emerging role of CXC chemokines in epithelial ovarian cancer

In recent years, chemokines have generated intense investigations due to their involvement in both physiological and pathological processes of inflammation, particularly in ovarian biology. The physiological process of ovulation in the normal ovary involves various chemokines that mediate the healing of the ruptured endometrium. It is now being reported that many of these chemokines are also associated with the cancer of the ovary. Chronic inflammation underlies the progression of ovarian cancer; therefore, it raises the possibility that chemokines are involved in the inflammatory process and mediate immune responses that may favour or inhibit tumour progression. Ovarian cancer is a gynaecological cancer responsible for highest rate of mortality in women. Although there have been several investigations and advances in surgery and chemotherapy, the survival rate for this disease remains low. This is mainly because of a lack of specific symptoms and biomarkers for detection. In this review, we have discussed the emerging role of the CXC chemokines in epithelial ovarian cancer (EOC). The CXC group of chemokines is gaining importance in the field of ovarian cancer for being angiostatic and angiogenic in function. While there have been several studies on the angiogenesis function, emerging research shows that ELR(-) CXC chemokines, CXCL9 and CXCL10, are angiostatic. Importantly, the angiostatic chemokines can inhibit the progression of EOC. Given that there are currently no biomarkers or specific therapeutic targets for the disease, these chemokines are emerging as promising targets for therapy.

T1N0/T2N0 glottic carcinoma: A comparison of two fractionation schedules

The aim of this paper is the retrospective comparison of accelerated/hypofractionated radiotherapy regimen (AHFX) with standard fractionation regimen (SFX) for patients with early glottic carcinoma. One hundred and forty-five patients with T(1)-T(2) glottic cancer between 1986 and 1998 were eligible. Before 1992, patients received 60-66 Gy in 30-33 fractions over 6-6.5 weeks (SFX) with (60)Co and 6-MV beams. After 1992, patients received 52.5-55 Gy in 20 fractions over 4 weeks (AHFX) using 6-MV beams. The end-points were overall survival, laryngectomy-free survival (LFS), loco-regional control and toxicity. One hundred and two were stage T(1)N(0); 43 were stage T(2)N(0). Median follow up was 4.9 years. The 5-year overall survival was 78%. Five-year loco-regional control in T(1)N(0) patients was higher in AHFX than in SFX group (95 vs 75%, P = 0.002). Loco-regional control in T(2)N(0) patients was similar for AHFX and SFX (81 vs 80%, P = 0.813). Overall LFS was 88%. T(1)N(0) AHFX patients had 5-year LFS of 95% compared with 75% for SFX (P = 0.003). For T(2)N(0) AHFX patients, overall LFS was 92% compared with 80% for the SFX group (P = 0.291). No grade 4 or 5 late toxicity occurred. One AHFX patient developed grade 3 toxicity; two of 51 SFX patients developed grade 2 toxicity versus five of 94 AHFX patients. AHFX using 6-MV beams for treatment of early glottic cancer resulted in equivalent LFS and toxicity when compared with SFX.

Chronic suppurative otitis media in the Solomon Islands: a prospective, microbiological, audiometric and therapeutic survey

Chronic suppurative otitis media affected 3.8% of 3500 Solomon Island children under 15 years (and 6.1% under 5 years) and was the sole cause of conductive hearing loss recorded in 265 children tested audiometrically. It was characterised by early onset (65% under 18 months) male preponderance and large central tubotympanic perforations. Measles, respiratory infections, swimming and malnutrition were identified as aetiological factors amenable to intervention. Proteus and pseudomonas were the principle aerobes isolated from ear pus and gentamicin the only antibiotic tested to be effective against them. However although a prospective therapeutic trial demonstrated a significantly improved outcome after aural toilet, no additional benefit was imparted by concurrent ototopical boric acid or aminoglycoside solution or oral antianaerobic clindamycin. Parental tuition in aural cleaning, avoidance of ear water entry, nose blowing and breathing will yield a good result in up to 60% of children in half of whom tympanic healing occurred.