Development of SarS-Cov-2 antigen Detection Kit Based on Immunoglobulin Y (Igy) Using Surface Plasmon resonance (SPr)

SARS disease reappeared at the end of 2019 with a new name as Coronavirus Disease 2019 (COVID-19) caused by a new virus called SARS-CoV-2. This virus has spread throughout the world until recently and caused massive deaths and losses. The nucleic acid test in the form of real-time reverse transcriptase-polymerase chain reaction (RT-PCR) is very important to diagnose COVID-19 in patients, but this method has several drawbacks such as operators who have to be trained, the diagnosis results appear in a relatively long time, and the examination price relatively expensive. This research was conducted to produce immunoglobulin Y (IgY) extracted from chicken egg yolk targeting the S-protein receptor-binding domain (RBD) on SARS-CoV-2 as a component of the surface plasmon resonance (SPR) SARS-CoV-2 antigen detection kit. This research was started by extracting IgY from hyperimmune chicken egg yolks with the polyethylene glycol (PEG) precipitation method and continued with dialysis. The extracted IgY was further purified using thiophilic adsorption chromatography and concentrated by using Amicon® Ultra-15 ultrafiltration. The IgY activity against SARS-CoV-2 RBD was tested qualitatively using the agar gel precipitation test (AGPT) technique and the total protein content was determined using the Lowry method. IgY was tested for its affinity against SARS-CoV-2 RBD using SPR. The IgY concentration obtained was 11 mg/mL. The AGPT result showed the presence of IgY activity against SARS-CoV-2 RBD isolated from egg yolk and chicken serum after 8 weeks after the first vaccination of chickens. The SDS-PAGE results showed a very clear band of IgY characters. The obtained IgY showed adequate interaction with commercial SARS-CoV-2 RBD on an SPR device. The purified IgY was able to bind with protein-S RBD and showed a fairly good affinity for the SARS-CoV-2 antigen sample. The results of these observations indicate that IgY anti-S-protein SARS-CoV-2 can be produced and purified from chicken egg yolk and can be used as a diagnostic component to detect SARS-CoV-2 antigen, especially on SPR.

Acidic and Heat Processing of Egg Yolk Dispersions

Egg yolk is a multifunctional ingredient widely used in many food products, wherein proteins are the dominant component contributing to this functionality. However, the potential risk of foodborne illness associated with egg use forces us to ensure that foodstuffs based on egg yolk are managed in a safe and sanitary manner. Lowering the pH under a certain value by adding acids could serve this purpose, but it can also greatly modify the rheological and functional properties of egg yolk. This research aims to assess the influence of citric acid on the rheological properties and microstructure of chicken egg yolk dispersions and their heat-set gels. The dispersions were prepared from fresh hen’s eggs yolks by adding water or citric acid to obtain a technical yolk (45 wt.% in solids) at the desired pH value. Viscoelastic measurements were carried out using a control stress rheometer, and microstructure was evaluated by cryo-scanning electronic microscopy (CryoSEM). An evolution of the viscoelastic properties of egg yolk dispersions from fluid to gel behavior was observed as the pH decreased until 2 but showing a predominantly fluid behavior at pH 3. The profile of viscoelastic properties along the thermal cycle applied is modified to a great extent, also showing a strong dependence on pH. Thus, the sol–gel transition can be modulated by the pH value.

Glucose inhibits haemostasis and accelerates diet-induced hyperlipidaemia in zebrafish larvae

Hyperglycaemia damages the microvasculature in part through the reduced recruitment of immune cells and interference with platelet signalling, leading to poor wound healing and accelerated lipid deposition in mammals. We investigated the utility of zebrafish larvae to model the effect of exogenous glucose on neutrophil and macrophage recruitment to a tail wound, wound-induced haemostasis, and chicken egg yolk feed challenge-induced hyperlipidaemia by supplementing larvae with exogenous glucose by immersion or injection. Neither method of glucose supplementation affected the recruitment of neutrophils and macrophages following tail transection. Glucose injection reduced thrombocyte retention and fibrin plug formation while only thrombocyte retention was reduced by glucose immersion following tail transection. We observed accelerated lipid accumulation in glucose-injected larvae challenged with high fat chicken egg yolk feeding. Our study identifies conserved and divergent effects of high glucose on inflammation, haemostasis, and hyperlipidaemia in zebrafish larvae compared to mammals.

Removal of Mixed-Species Biofilms Developed on Food Contact Surfaces with a Mixture of Enzymes and Chemical Agents

Sanicip Bio Control (SBC) is a novel product developed in Mexico for biofilms’ removal. The aims of this study were to evaluate (i) the removal of mixed-species biofilms by enzymatic (protease and α-amylase, 180 MWU/g) and chemical treatments (30 mL/L SBC, and 200 mg/L peracetic acid, PAA) and (ii) their effectiveness against planktonic cells. Mixed-species biofilms were developed on stainless steel (SS) and polypropylene B (PP) in whole milk (WM), tryptic soy broth (TSB) with meat extract (TSB+ME), and TSB with chicken egg yolk (TSB+EY) to simulate the food processing environment. On SS, all biofilms were removed after treatments, except the enzymatic treatment that only reduced 1–2 log10 CFU/cm2, whereas on PP, the reductions ranged between 0.59 and 5.21 log10 CFU/cm2, being the biofilms developed in TSB+EY being resistant to the cleaning and disinfecting process. Higher reductions in microbial load on PP were reached using enzymes, SBC, and PAA. The employed planktonic cells were markedly more sensitive to PAA and SBC than were the sessile cells. In conclusion, biofilm removal from SS can be achieved with SBC, enzymes, or PAA. It is important to note that the biofilm removal was strongly affected by the food contact surfaces (FCSs) and surrounding media.

Evaluation of the purification process of phosvitin extracted from chicken egg yolk using liquid chromatography

Phosvitin from chicken egg yolk, known as a phosphoglycoprotein, owns a very strong metal chelating property due to its polyanionic character. This study aimed to evaluate the factors affecting the purification process and suitable conditions to increase phosvitin’s purity. Phosvitin was separated from yolk granules by using 10% of NaCl solution in 0.05 M NaOH solution and heat treatment which removes lipoprotein from the extracted solution. The highest phosphorus content (58.14 mg) and phosphorus recovery rate (32.4%) were obtained at thermal treatment of 30℃ for 30 minutes. In addition, phosvitin was purified using anion-exchange chromatography (AEC) and gel-filtration chromatography (GFC). The fraction 1 (F1) obtained from AEC using UNO-Sphere Q at pH 8 had the recovery rate of phosvitin approximately 72.73%. Furthermore, fraction F1 was separated on GFC to obtain two main sub-fractions (F1 and F2). Sub-fraction F1 from gel filtration was composed mostly of β-phosvitin with a high recovery rate (81.93%) while F2 was dominant with α-phosvitin in a lower phosvitin recovery rate (16.89%). These findings will provide useful information for further researches on other properties of phosvitin so that it can be applied widely in human needs.

PERBANDINGAN PEMBERIAN MINYAK KUNING TELUR AYAM DAN BIOPLACENTON TERHADAP GAMBARAN HISTOLOGI KULIT

This study was conducted to determine the comparison of re-epithelialization, granulation and the number of inflammatory cells infiltration between topical application of chicken yolk oil and bioplacenton on white rat (Rattus norvegicus) skin that has induced with second degree burn wound. This research was a laboratory experimental study using 18 male white rats divided into control positive (K+) group, bioplacenton (P1) and chicken yolk oil (P2). Observation of the re-epithelialization, granulation and inflammatory cells infiltration were carried out 14 days after the rat were induced with second degree burn wound. The necropcy was performed on the 14th day and then the skin organs were treated with HE staining and observed under a microscope. Data analysis was performed using Kruskal-Wallis followed by Mann Whitney. The results of the analysis showed that K + had significantly different results (P <0.05) compared to P1 and P2 in the scores of re-epithelialization, granulation and the number of inflammatory cell infiltrations. P1 and P2 were not significantly different (P> 0.05). In this study, it can be concluded that chicken egg yolk has a comparable effect with bioplacenton toward the score of re-epithelialization, granulation and the number of inflammatory cell infiltration.