Partial Replacement Of Protein Research Articles

The influence of environmental awareness on inducing lower carbon dietary change in the UK

This study was undertaken to address the detrimental environmental impacts resulting from common diets in the UK. Lower carbon dietary change is recognised as a practice which, if encouraged, could contribute towards the achievement of national climate change targets. In this study, lower carbon dietary change consists of diets which involve reduced traditional meat consumption, as well as those with increased levels of insect meat consumption, either as a partial or primary protein replacement to traditional meat sources. Using Southampton as a study area, an experimental intervention was implemented within questionnaires (N=507) to determine whether awareness of the environmental benefits of insect consumption over traditional meat sources could be used to facilitate a shift towards the adoption of lower carbon diets. Experimental intervention influenced preparedness for different forms of lower carbon dietary change to varying extents. Reducing consumption of traditional meat sources was found to be the most favourable form of lower carbon dietary change. The consumption of insects as a partial protein replacement to traditional meat sources was somewhat more favourable than consumption as a primary protein source; however, a large proportion of individuals were reluctant towards the concept. Education, age and gender were all factors which influenced preparedness for insect consumption, but did not impact upon preparedness to reduce traditional meat consumption to the same extent. It is evident that environmental awareness can partly impact upon preparedness towards lower carbon dietary change; however, other drivers such as personal health and animal welfare were found to exert stronger influence. It is suggested that future research efforts in the UK should be directed towards ensuring the relationship between the environment and dietary choices is better understood amongst consumers, as well as gauging the extent to which additional drivers can facilitate a shift towards lower carbon dietary change.

Analysis of Human Protein Replacement Stable Cell Lines Established using snoMEN-PR Vector

The study of the function of many human proteins is often hampered by technical limitations, such as cytotoxicity and phenotypes that result from overexpression of the protein of interest together with the endogenous version. Here we present the snoMEN (snoRNA Modulator of gene ExpressioN) vector technology for generating stable cell lines where expression of the endogenous protein can be reduced and replaced by an exogenous protein, such as a fluorescent protein (FP)-tagged version. SnoMEN are snoRNAs engineered to contain complementary sequences that can promote knock-down of targeted RNAs. We have established and characterised two such partial protein replacement human cell lines (snoMEN-PR). Quantitative mass spectrometry was used to analyse the specificity of knock-down and replacement at the protein level and also showed an increased pull-down efficiency of protein complexes containing exogenous, tagged proteins in the protein replacement cell lines, as compared with conventional co-expression strategies. The snoMEN approach facilitates the study of mammalian proteins, particularly those that have so far been difficult to investigate by exogenous expression and has wide applications in basic and applied gene-expression research.

Dietary protein differentially regulates the kinetic behaviour of serine dehydratase and tyrosine aminotransferase of liver and white muscle of rainbow trout (Oncorhynchus mykiss)

We have determined the kinetic behaviour of serine dehydratase (SerDH) and tyrosine aminotransferase (TyrAT) in the liver and white muscle of juvenile rainbow trout (Oncorhynchus mykiss) fed on a low-protein/high-fat (LP/HF) and control diets. The relationship between the kinetic parameters and tissue-DNA concentration has also been determined. SerDH and TyrAT showed hyperbolic kinetics in all cases. The partial replacement of protein with fat significantly increased hepatic SerDH-specific activity, maximum velocity (V(max)) and Michaelis constant (K(m)) while no significant changes were detected in the values of these parameters in white muscle. Nevertheless, hepatic and white-muscle TyrAT specific activity and V(max) decreased in trout fed on LP/HF diet with respect to control. The K(m) of hepatic TyrAT was also lower in trout fed on LP/HF diet than in control. The TyrAT kinetic parameters expressed per cell unit also changed in the same sense as previously described. These results show that, in trout, SerDH and TyrAT are two enzymes regulated by the partial replacement of dietary protein by fat.

Dietary alterations in protein, carbohydrates and fat increase liver protein-turnover rate and decrease overall growth rate in the rainbow trout (Oncorhynchus mykiss).

We have determined the protein-turnover rates and nucleic-acid concentrations in the liver of trout (Oncorhynchus mykiss) fed on two different isocaloric diets: low-protein/high-fat and non-carbohydrate/high-fat. Compared to controls, the partial replacement of protein with fat significantly decreased the protein accumulation rate and protein-retention efficiency in the liver whilst increasing the fractional protein-synthesis and protein-degradation rates as well as protein-synthesis efficiency. The complete replacement of carbohydrates with fat significantly lowered the protein-accumulation rate and protein-retention efficiency, but enhanced both the protein-synthesis and protein-degradation rates as well as protein-synthesis capacity. The protein:DNA and RNA:DNA ratios decreased considerably on both diets. Total DNA decreased in fish on a low-protein/high-fat diet but did not change in those on a non-carbohydrate/high-fat diet. The absolute protein-synthesis rate registered no significant change under any of the nutritional conditions. Both the experimental diets did however raise the fractional protein-synthesis rate significantly, due to enhanced protein-synthesis efficiency when protein was partially replaced with fat and to enhanced protein-synthesis capacity when carbohydrates were completely replaced with fat. Our results show the capacity of the liver to adapt its turnover rates and conform to different nutritional conditions. They also point to the possibility of controlling fish growth by dietary means.

The effects of composition and some processing treatments on the rennet coagulation properties of milk

The effects of various processing parameters on the rennet coagulation properties of milk were assessed. Using low amplitude oscillation rheometry, the coagulation properties were monitored by measurement of the elastic shear modulus, G', as a function of time, t, from rennet addition; Gapos; was taken as a measure of curd firmness. The Scott‐Blair time dependency model was fitted to the experimental G' It curves for the determination of the following coagulation parameters: gel time, maximum curd firming rate, the set‐to‐cut time at 20 Pa (ie, time to reach 20 Pa) and the curd firmness after a renneting time of 2400 s. The renneting properties were enhanced by increasing the levels of milk protein and fat in the ranges 0.3–7.0% (w/w) and 0.1–10% (w/w) respectively and by two stage homogenization pressure where the first stage pressure, P1, was varied from 0 to 25 MPa and the second stage pressure, P2, was held constant at 5 MP a. The influence of these parameters, within the range investigated, in complementing the gel forming properties decreased in the following order: protein > fat > homogenization pressure. In contrast, the coagulation properties of milk were impaired by high heat treatment, the addition of a commercial microparticulated whey protein based fat substitute and by partial replacement of protein with fat.