COVID-19 Neutralizing Antibody Surveillance Testing for Fully Vaccinated Individuals During Delta Variant Spread

We recently performed 568 rapid neutralizing antibody (NAb) tests on 164 fully vaccinated individuals who received either Moderna or Pfizer COVID-19 vaccine regimens over 7 weeks. The NAb levels against the wild type (WA1/2020), Delta, and Kappa variants were measured and compared. Depending on each individual's medical condition and vaccination status, the NAb levels for most of the fully vaccinated people decreased within 2-6 months, while a small number of individuals either generated non-detectable amount of NAbs after full vaccination (e.g., immunocompromised), or had high NAb levels lasting beyond 6 months. Since the NAb levels vary significantly among different individuals and decrease over time, the deployment of a low-cost rapid test to monitor NAb levels against both the wild type and emerging variants among fully vaccinated individuals can play a very crucial role to control the current pandemic. Our study provides an example of using such a rapid NAb test to fill this currently unmet medical need.

Seroprevalence and Dynamics of anti-SARS-CoV-2 antibody among healthcare workers following ChAdOx1 nCoV-19 vaccination

Background The serological evaluations of IgG, IgM, and IgA to the SARS-CoV-2 proteins are widely used for the epidemiological assessment of COVID-19. The Health Care Workers (HCWs) are presumably exposed to a higher risk of acquiring the disease owing to their regular contact with the patients. Methods COVID-19 prevalence was investigated by classifying 313 HCWs into four groups based on their degree of exposure and estimating the IgG and total antibody. The serological assessment of the anti-SARS-CoV-2 antibody was conducted 21 days post-vaccination of first or both doses of the ChAdOx1 nCoV-19 vaccine among 174 HCWs. The vaccinated HCWs were followed up for 3 months for SARS-CoV-2 infection. Findings The levels of anti-SARS-CoV-2 IgG were comparable among different groups, but the seroprevalence gradually decreased from the most exposed to the less exposed group. The neutralizing antibody was positively correlated with IgG as well as total antibody. IgG was marginally decreased after 2 months followed by a significant drop after 4-6 months post-infection. However, 80% of the HCWs developed a detectable amount of IgG after the first dose of vaccination, the median titer of which was comparable to the seropositive HCWs after natural infection. Almost 100% of the HCWs developed antibodies after the second dose of vaccine with boosting effect among the seropositive HCWs. Although ~11.5% of the vaccinated HCWs were infected with the SARS-CoV-2, ~94% of them showed mild symptoms and recovered in home isolation without any O2 support. Interpretations The varying level of seroprevalence among the four groups suggested a stratified spread of the disease. One dose of SARS-CoV-2 vaccination was found to be effective in terms of the antibody titer, while the second dose was required to cover the larger population. The effectiveness of the ChAdOx1 nCoV-19 vaccine was noticeable due to the low rate of post-vaccination infection with moderate or severe symptoms.

Gentle Sterilization of Carrot-Based Purees by High-Pressure Thermal Sterilization and Ohmic Heating and Influence on Food Processing Contaminants and Quality Attributes

Pressure-enhanced sterilization (PES) and ohmic heating (OH) are two emerging sterilization techniques, currently lacking implementation in the food industry. However, both technologies offer significant benefits in terms of spore inactivation using reduced thermal intensity in food products, as well as minimized effects on sensory and nutritional profiles. In this study, PES and OH were tested based on possible food safety process windows in comparison to thermal retorting, to optimize the food quality of carrot-based purees. The following parameters related to food quality were tested: texture, carotenoid content, color, and detectable amount of food processing contaminants (FPC) formed. Application of the innovative sterilization techniques resulted in a better retention of color, texture, and carotenoids (for PES) as well as a reduced formation of food processing contaminants. Importantly, a significant reduction in the formation of furan and its derivates was observed, compared to the retorted samples. Hence, both sterilization technologies showed promising results in the mitigation of potential toxic processing contaminants and retention of quality attributes.

Evaluation of four commercial DNA extraction kits for the detection of Microsporidia and the importance of pretreatments in DNA isolation

Microsporidia are obligate intracellular parasitic protozoa infecting the wide variety of hosts and are commonly known as a cause of chronic diarrhea particularly in immunocompromised individuals. Molecular-based tests have high sensitivity and specificity in disease diagnosis. However, these tests’ performance relies on the isolation of DNA in a good concentration. The standard procedures of commercial DNA extraction kits are usually insufficient for this purpose due to the tough walls of spores. This study aimed to test the significance of pretreatments by glass beads and freeze-thawing processes in DNA isolation from microsporidia spores. The parasite was cultured in growing Vero cells and seven serial dilutions were prepared from the collected spores. DNA purification was performed according to different tissue kits and stool kit procedures with and without any pretreatment. Concentration of isolated DNA samples were evaluated by real-time PCR. As a result of this study, the detectable amount of spores is minimum 10 spores in each 100 μ! sample according to the different tissue kits’ standard protocols. However, according to the DNA stool mini kit, the detectable amount of spores was found to be 1,000 spores/100 μl of stool sample when pretreated with both the freeze-thawing and glass beads methods.In conclusion, the current study demonstrated that further pretreatments are an essential process for DNA extraction from the stool specimens in order to avoid possible false negativity in the diagnosis of microsporidiosis.

Residues of organochlorine pesticides in irrigated sierozem-meadow soils around buried chemicals stock

The concentration and distribution of organochlorine pesticides (OCPs) were studied in sierozem-meadow soils around a buried obsolete chemicals stock in Mirzaabad district of Syrdarya region of Uzbekistan. 23 soil samples were collected from the topsoil (0–30 cm of soil depth) and 15 samples were collected from three soil profiles (down to 125 cm of soil depth) located in nearby vicinity of the stock. They were extracted using an automated Soxhlet extractor and analyses were done by gas chromatography-mass spectrometry. The detected OCPs were DDTs, HCHs, aldrin, dieldrin, endrin, chlorpyrifos, and endosulfans. The concentration of HCH was detected only as α-HCH in the range of 0–3.159 μg/kg. Only two isomers of DDT: p,p'-DDE and p,p'-DDD were found to be dominant, with the range of their values of 0.068-4.941 and 0-13.63 μg/kg, respectively. The concentrations of aldrin, dieldrin, endrin and chlorpyrifos in the samples collected around the source were in the range of 0–0.504, 0–1.117, 2.414–20.87 μg/kg and 0–3.819 μg/kg. β-endosulfan varied from a non-detectable amount to 74.56 μg/kg. According to results, the sum of DDTs was observed to be higher in the upper horizons, especially at depths of 0–10 and 10–50 cm, with the values 543.15 and 212.22 μg/kg, respectively, which can be a cause of concern. Due to their ability to migrate in the environment, accumulate in the food chain and be harmful to human health, monitoring the level of residues of organochlorine pesticides in soil is of vital importance.

The pattern of IgG concentration in neonatal lamb's sera from birth till 7th day (168th hour)

A quantitation of IgG was made, using R.I.D test, in blood sera of 15 newborn iambs. The quantity of IgG was measured in time intervals immediately after birth and before suckling till 168th hour after birth. Two lambs out of 15 have detectable amount of IgG in their sera before suckling. The maximum concentration of IgG in 11 lambs sera was measured 24 hours, in 3 lambs sera 36 hours, and in 1 lamb's serum 48 hours after birth, respectively. In three lambs out of 15, a percentage of 20%, the serum concentration of IgG was less than 30 mg/ml. One of these lambs died and another got ill 120 hours after birth.

Chitinases and endoglucanases synthesized in the infected barley leaves in the powdery mildew period sporulation

In our work, we represent genetic, molecular and biochemical changes induced in the infected barley leaves induced in the period pathogen sporulation. We studied a presence of acidic β-1,3-endoglucanases and chitinases in an intracellular fluid isolated from primary barley leaves infected with two powdery mildew pathotypes carrying various virulence genes. In the period of pathogen sporulation acidic β-1,3-endoglucanases (Glu) and chitinases (Chi) isozymes were synthesized in two main groups. Non-specific, high molecular group of these enzymes with Mr > 200 kDa did not differ genetic differences between host and pathogen. Specific, low molecular forms reflected both genetic background of host and pathogen as well as biochemical status of the disease. Low molecular acidic Glu had Mr from interval 9–12 kDa. Analogical situation was observed for low molecular chitinases. Their molecular masses were from interval 14.4–15.5 kDa. Intracellular fluid from the primary leaves of the healthy plants did not contained detectable amount of these enzymes. Appearance of low molecular forms of Glu and Chi is discussed.