New Views of Protein Structure: Applications to the Caseins: Protein Structure and Functionality

Advances in the field of protein chemistry have enhanced our understanding of the possible intermediates which may occur during protein folding and unfolding. An enormous amount of information has been generated on folding pathways of globular proteins leading to the discovery of the molten globule state as a specific folding intermediate. Other partially folded conformations including pre-molten globule have been found that are intermediate between the random coils and compact globular conformations. Furthermore, many proteins appear as natively unfolded, intrinsically unstructured, or intrinsically disordered under physiological conditions. Purified caseins are not truly random coils, but appear to share many of the properties of these newly described intermediate states. Since casein structure is still being debated, clarifying how the caseins fit with these newly described protein states how the caseins fit with these newly described protein states would be beneficial. In this review quantitative measures based upon known physical and chemical properties of the caseins are used for their classification. By taking advantage of this new view of protein folding, and applying these concepts to casein fractions it may be possible to generate new potential food products from casein or casein fractions. Such products could also have neutraceutical or nanotechnological applications

New Views of Protein Structure: Implications for Potential New Protein Structure-function Relationships

Recent advances in the field of protein chemistry have significantly enhanced our understanding of the possible intermediates which may occur during protein folding and unfolding. In particular, studies on α-lactalbumin have led to the theory that the molten globule state may be one possible intermediate in the folding of many proteins. The molten globule state is characterized by a compact structure, a high degree of hydration and side chain flexibility, a significant amount of native secondary structure but little tertiary structure, and the ability to react with chaperones. Other partially folded conformations (e.g., pre-molten globule) have also been found. Many proteins known as natively unfolded, intrinsically unstructured, or intrinsically disordered were shown to be highly flexible under physiological conditions. By taking advantage of this new view of protein folding, and applying these concepts to engineered macromolecules and food proteins, it may be possible to generate new and useful forms of proteins for the food ingredient, pharmaceutical and nanotechnological markets

Reactions between β-Lactoglobulin and Genipin: Kinetics and Characterization of the Products

In this paper, we present the first detailed study of the reaction kinetics and the characterization of the products from the endothermic reactions between β-lactoglobulin and genipin. The effects of the concentration, temperature, and pH were investigated. In the temperature range studied, the reaction was approximately a pseudo-first-order with respect to genipin and 0.22-order and −0.24-order with respect to β-lactoglobulin for pH 6.75 and 10.5 with corresponding activation energy (<i>E</i>_a) estimated to be 66.2 ± 3.8 and 9.40 ± 0.36 kJ/mol, respectively. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis studies, validated by matrix-assisted laser desorption ionization–time of flight mass spectrometry, showed the presence of oligomeric, i.e., di-, tri-, quadri-, and pentameric, forms of cross-linked β-lactoglobulin by genipin at neutral but not alkaline pH; however, an extensive cross-linked network was not observed, consistent with the atomic force microscopy images. It was demonstrated that the reaction temperature and the concentration of genipin but not that of β-lactoglobulin positively affected the extent of the cross-linking reactions

Anti-listerial activity of thermophilin 110 and pediocin in fermented milk and whey

Listeria monocytogenes is a pathogenic bacterium responsible for foodborne illness worldwide. Antimicrobial peptides, or bacteriocins, produced by food-grade lactic acid bacteria can serve as preservatives to prevent Listeria’s growth in various foods, including dairy products. This study investigated the anti-listerial activities of bacteriocin-producing lactic acid bacteria, Streptococcus thermophilus B59671, and Lactobacillus plantarum 076. In vitro studies showed that the concentration of pediocin produced by L. plantarum 076 (2560 AU/mL) inhibited the growth of a six-strain cocktail of L. monocytogenes. However, the concentration of thermophilin 110 produced by S. thermophilus B59671 (320 AU/mL) only delayed the growth by ~2 h. Higher concentrations of thermophilin 110 (≥640 AU/mL) suppressed Listeria growth for up to 22 h. Pasteurized skim milk fermented with a co-culture of S. thermophilus B59671 and L. plantarum 076 reduced the number of L. monocytogenes cells by > 4 Log CFU/mL due mainly to the activity of pediocin. The anti-listerial activity was not observed in whey samples collected from pasteurized skim milk fermented with this co-culture but was detected when raw milk was the substrate. Two additional whey preparations, the by-products from commercial bovine and goat raw-milk cheeses, also inhibited Listeria growth and reduced the number of cells following storage at 4 ◦C for one week. This study showed that a concentrated preparation of thermophilin 110 has potential as an anti-listerial compound. It demonstrated the prospect of using a co-culture of S. thermophilus B59671 and L. plantarum 076 to prevent Listeria contamination in dairy foods. Additionally, results showed that metabolites with antimicrobial activities may be generated during the fermentation of raw milk due to indigenous microflora

Search for the rare hadronic decay Bs0→ppˉB_s^0\to p \bar{p}

A search for the rare hadronic decay Bs0→pp¯ is performed using proton-proton collision data recorded by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6  fb-1. No evidence of the decay is found and an upper limit on its branching fraction is set at B(Bs0→pp¯)&lt;4.4(5.1)×10-9 at 90% (95%) confidence level; this is currently the world’s best upper limit. The decay mode B0→pp¯ is measured with very large significance, confirming the first observation by the LHCb experiment in 2017. The branching fraction is determined to be B(B0→pp¯)=(1.27±0.15±0.05±0.04)×10-8, where the first uncertainty is statistical, the second is systematic and the third is due to the external branching fraction of the normalization channel B0→K+π-. The combination of the two LHCb measurements of the B0→pp¯ branching fraction yields B(B0→pp¯)=(1.27±0.13±0.05±0.03)×10-8.A search for the rare hadronic decay $B_s^0\to p \bar{p}$ is performed using proton-proton collision data recorded by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb$^{-1}$. No evidence of the decay is found and an upper limit on its branching fraction is set at ${\cal B}(B_s^0\to p \bar{p}) < 4.4~(5.1) \times 10^{-9}$ at 90% (95%) confidence level; this is currently the world's best upper limit. The decay mode $B^0\to p \bar{p}$ is measured with very large significance, confirming the first observation by the LHCb experiment in 2017. The branching fraction is determined to be ${\cal B}(B^0\to p \bar{p}) = \rm (1.27 \pm 0.15 \pm 0.05 \pm 0.04) \times 10^{-8}$, where the first uncertainty is statistical, the second is systematic and the third is due to the external branching fraction of the normalization channel $B^0\to K^+\pi^-$. The combination of the two LHCb measurements of the $B^0\to p \bar{p}$ branching fraction yields ${\cal B}(B^0\to p \bar{p}) = \rm (1.27 \pm 0.13 \pm 0.05 \pm 0.03) \times 10^{-8}$

Nuclear modification factor of neutral pions in the forward and backward regions in ppPb collisions

The nuclear modification factor of neutral pions is measured in proton-lead collisions collected at a center-of-mass energy per nucleon of $8.16$ TeV with the LHCb detector. The $\pi^0$ production cross section is measured differentially in transverse momentum ($p_{T}$) for 1.5π0 production cross section is measured differentially in transverse momentum (pT) for 1.5<pT<10.0  GeV and in center-of-mass pseudorapidity (ηc.m.) regions 2.5<ηc.m.<3.5 (forward) and -4.0<ηc.m.<-3.0 (backward) defined relative to the proton beam direction. The forward measurement shows a sizable suppression of π0 production, while the backward measurement shows the first evidence of π0 enhancement in proton-lead collisions at the LHC. Together, these measurements provide precise constraints on models of nuclear structure and particle production in high-energy nuclear collisions.The nuclear modification factor of neutral pions is measured in proton-lead collisions collected at a center-of-mass energy per nucleon of 8.16~{\rm TeV}$with the LHCb detector. The$\pi^0$production cross section is measured differentially in transverse momentum ($p_{\rm T}$) for$1.5<p_{\rm T}<10.0~{\rm GeV}$and in center-of-mass pseudorapidity ($\eta_{\rm c.m.}$) regions$2.5<\eta_{\rm c.m.}<3.5$(forward) and$-4.0<\eta_{\rm c.m.}<-3.0$(backward) defined relative to the proton beam direction. The forward measurement shows a sizable suppression of$\pi^0$production, while the backward measurement shows the first evidence of$\pi^0$ enhancement in proton-lead collisions at the LHC. Together, these measurements provide precise constraints on models of nuclear structure and particle production in high-energy nuclear collisions

Measurement of CP asymmetries in D(s)+→ηπ+ {D}_{(s)}^{+}\to \eta {\pi}^{+} and D(s)+→η′π+ {D}_{(s)}^{+}\to {\eta}^{\prime }{\pi}^{+} decays

Searches for CP violation in the decays ${D}_{(s)}^{+}\to \eta {\pi}^{+}$ and ${D}_{(s)}^{+}\to {\eta}^{\prime }{\pi}^{+}$ are performed using pp collision data corresponding to 6 fb$^{−1}$ of integrated luminosity collected by the LHCb experiment. The calibration channels ${D}_{(s)}^{+}\to \phi {\pi}^{+}$ are used to remove production and detection asymmetries. The resulting CP-violating asymmetries are${\displaystyle \begin{array}{l}{\mathcal{A}}^{CP}=\left({D}^{+}\to \eta {\pi}^{+}\right)=\left(0.34\pm 0.66\pm 0.16\pm 0.05\right)\%,\\ {}{\mathcal{A}}^{CP}=\left({D}_s^{+}\to \eta {\pi}^{+}\right)=\left(0.32\pm 0.51\pm 0.12\right)\%,\\ {}\begin{array}{l}{\mathcal{A}}^{CP}=\left({D}^{+}\to {\eta}^{\prime }{\pi}^{+}\right)=\left(0.49\pm 0.18\pm 0.06\pm 0.05\right)\%,\\ {}{\mathcal{A}}^{CP}=\left({D}_s^{+}\to {\eta}^{\prime }{\pi}^{+}\right)=\left(0.01\pm 0.12\pm 0.08\right)\%,\end{array}\end{array}}$where the first uncertainty is statistical, the second is systematic and the third, relevant for the D$^{+}$ channels, is due to the uncertainty on ${\mathcal{A}}^{CP}=\left({D}^{+}\to \phi {\pi}^{+}\right)$. These measurements, currently the most precise for three of the four channels considered, are consistent with the absence of CP violation. A combination of these results with previous LHCb measurements is presented.[graphic not available: see fulltext]Searches for $CP$ violation in the decays $D^+_{(s)}\rightarrow \eta \pi^+$ and $D^+_{(s)}\rightarrow \eta^{\prime} \pi^+$ are performed using $pp$ collision data corresponding to 6 fb$^{-1}$ of integrated luminosity collected by the LHCb experiment. The calibration channels $D^+_{(s)}\rightarrow \phi \pi^+$ are used to remove production and detection asymmetries. The resulting $CP$-violating asymmetries are $A^{CP}(D^+ \rightarrow \eta \pi^+) = (0.34 \pm 0.66 \pm 0.16 \pm 0.05)\%$, $A^{CP}(D^+_s \rightarrow \eta \pi^+) = (0.32 \pm 0.51 \pm 0.12)\%$, $A^{CP}(D^+ \rightarrow \eta^{\prime} \pi^+) = (0.49 \pm 0.18 \pm 0.06 \pm 0.05)\%$, $A^{CP}(D^+_s \rightarrow \eta^{\prime} \pi^+) = (0.01 \pm 0.12 \pm 0.08)\%$, where the first uncertainty is statistical, the second is systematic and the third, relevant for the $D^+$ channels, is due to the uncertainty on $A^{CP}(D^+ \to \phi \pi^+)$. These measurements, currently the most precise for three of the four channels considered, are consistent with the absence of $CP$ violation. A combination of these results with previous LHCb measurements is presented