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BACKGROUND: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes the coronavirus disease 2019 (COVID-19), which first appeared in December 2019. Angiotensin I converting enzyme 2 (ACE2) receptor, present on the host cells, interacts with the receptor binding domain (RBD) of spike (S) protein of SARS-CoV-2 and facilitates the viral entry into host cells. METHODS: Non-synonymous single nucleotide polymorphisms (nsSNPs) in the ACE2 gene may have an impact on the protein's stability and its function. The deleterious or harmful nsSNPs of the ACE2 gene that can change the strength as well as the pattern of interaction with the RBD of S protein were selected for this study. RESULTS: The ACE2:RBD interactions were analyzed by protein-protein docking study. The missense mutations A242V, R708W, G405E, D292N, Y633C, F308L, and G405E in ACE2 receptor were found to interact with RBD of Omicron subvariants with stronger binding affinity. Among the other selected nsSNPs of human ACE2 (hACE2), R768W, Y654S, F588S, R710C, R710C, A191P, and R710C were found to have lower binding affinity for RBD of Omicron subvariants. CONCLUSION: The findings of this study suggest that the nsSNPs present in the human ACE2 gene alter the structure and function of the protein and, consequently, the susceptibility to Omicron subvariants.

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Polyphosphate polymers are chains of phosphate monomers chemically bonded together via phosphoanhydride bonds. They are found in all prokaryotic and eukaryotic organisms and are among the earliest, most anionic, and most mysterious molecules known. They are everywhere, from small cellular components to additives in our food. There is a strong association between hyperphosphatemia and mortality. That is why it is crucial to assess how polyphosphates, as food additives, affect the quality of edible proteins. This study investigated the effect of inexpensive and widely used food additives (hexametaphosphate labeled as E452) on bakery items, meat products, fish, and soft drinks. Using various spectroscopic and microscopic techniques, we examined how hexametaphosphate affected the aggregation propensity, structure, and stability of a commonly used food protein: hen egg white lysozyme (HEWL). The solubility of HEWL is affected in a bimodal fashion by the concentration of hexametaphosphate. The bimodal concentration-dependent effect was also observed in the tertiary and secondary structural changes. Hexametaphosphate-induced HEWL aggregates were amorphous, as evidenced by ThT fluorescence, far-UV CD, and TEM imaging. This study showed that the food additive (hexametaphosphate) may denature and aggregate proteins and may lead to undesirable health issues.

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The mechanism by which anionic surfactants promote amyloid fibril is not well understood. Here, we investigated how sodium dodecyl sulfate (SDS), a negatively charged surfactant, affects the fibrillation of the partially unfolded random-coiled bovine liver catalase (BLC) at a pH of 2.0. We used several methods, including turbidity, RLS kinetics, intrinsic fluorescence, ThT fluorescence, far-UV CD, and TEM imaging, to evaluate the conformational changes of BLC in vitro in response to SDS treatment. BLC is a multimeric protein and well folded at physiological pH but forms a random coil structure at pH 2.0. Intrinsic fluorescence and far-UV CD data showed that below 0.1 mM SDS, random coiled BLC turned into a native-like structure. BLC incubated with an SDS concentration ranging from 0.1 to 2.0 mM led to the formation of aggregates. The ThT fluorescence intensity was enhanced in the aggregated BLC samples (0.1-2.0 mM SDS), and cross beta-sheeted structure was detected by the far UV CD measurements. BLC adopts a complete alpha-helical structure upon interacting with SDS at a more than 2.0 mM concentration at pH 2.0. Understanding the mechanism of surfactant- or lipid-induced fibrillation is important for therapeutic purposes.

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Caffeic acid (CA) is a phenolic acid found in a variety of foods. In this study, the interaction mechanism between α-lactalbumin (ALA) and CA was explored with the use of spectroscopic and computational techniques. The Stern-Volmer quenching constant data suggest a static mode of quenching between CA and ALA, depicting a gradual decrease in quenching constants with temperature rise. The binding constant, Gibbs free energy, enthalpy, and entropy values at 288, 298, and 310 K were calculated, and the obtained values suggest that the reaction is spontaneous and exothermic. Both in vitro and in silico studies show that hydrogen bonding is the dominant force in the CA-ALA interaction. Ser112 and Lys108 of ALA are predicted to form three hydrogen bonds with CA. The UV-visible spectroscopy measurements demonstrated that the absorbance peak A280nm increased after addition of CA due to conformational change. The secondary structure of ALA was also slightly modified due to CA interaction. The circular dichroism (CD) studies showed that ALA gains more α-helical structure in response to increasing concentration of CA. The surface hydrophobicity of ALA is not changed in the presence of ethanol and CA. The present findings shown herein are helpful in understanding the binding mechanism of CA with whey proteins for the dairy processing industry and food nutrition security.

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Chalcid Brachymeria podagrica (Fabricius), formerly known as Brachymeria fonscolombei (Dufour), is a parasitoid wasp that infests dipteran larvae of fly, Sarcophaga dux (Thomson), (Diptera: Sarcophagidae) recovered from the dead body of sheep in Bisha City, Asir region-Saudi Arabia. S. dux larvae were infested by B. podagrica. The first instar larvae and pupae of B. podagrica were found inside the larvae and pupae of S. dux. The adults of the parasitic wasp emerged from the pupae of the host. Adults and larvae of the parasitoid wasp were observed under a dissecting microscope. Identification was made by following the identification keys. It was confirmed that it was B. podagrica, which is herewith reported for the first time in Saudi Arabia.

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OBJECTIVES: The present study was designed to determine the prevalence of premature loss of primary teeth and its effect on malocclusion in Eastern Province, Saudi Arabia. MATERIALS AND METHODS: This is an observational, cross-sectional study that included 307 male children aged 9-11 years old. Clinical examinations were performed using a disposable sharp explorer, a UNC periodontal probe and a dental mirror. The samples were examined clinically to detect the following traits: Angle's classification of malocclusion, overjet, overbite, anterior open-bite, lateral open-bite, midline shift and cross-bite. Additionally, a dental caries examination was performed using WHO methods. Questionnaires in Arabic were coded and sent to the students' parents. RESULTS: The mean DMFT was 5.61 (SD = 3.01). The d-component was the highest, with a mean of 4 (SD = 2.83). Of the 307 children, it was found that 204 (66.4%) had a high DMFT score, which is defined as a score above 4. It was found that 156/307 (51%) children had premature loss of deciduous teeth. CONCLUSION: A high prevalence of premature loss of teeth was found in this study. This finding emphasizes the importance of increasing awareness levels about this issue and focuses attention on the need for more preventive efforts to maintain healthy and normal dentitions that would improve the masticatory function and aesthetics of individuals and the whole population. In addition, the findings emphasize the importance of the early detection of premature loss of primary teeth to prevent future malocclusion.

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