The Mutational Landscape of SARS-CoV-2 Variants of Concern Recovered From Egyptian Patients in 2021

In December 2019, a mysterious viral pneumonia first developed in Wuhan, China, resulting in a huge number of fatal cases. This pneumonia, which was named COVID-19, was attributed to a novel coronavirus, SARS-CoV-2. The emerging SARS-CoV-2 mutations pose the greatest risk to human health because they could result in an increase in the COVID-19 severity or the failure of current vaccines. One of these notable mutations is the SARS-CoV-2 Delta variant (B.1.617) that was first detected in India and has rapidly expanded to 115 countries worldwide. Consequently, in this study, we performed next-generation sequencing and phylogenetic analysis of SARS-CoV-2 during the third wave of the pandemic to determine the SARS-CoV-2 variants of concern (VOC) prevalence in Egypt. We observed several mutational patterns, revealing that SARS-CoV-2 evolution has expanded in Egypt with a considerable increase in the number of VOC. Therefore, the Egyptian authorities should take an appropriate approach to investigate the compatibility of already employed vaccines with this VOC and to examine the efficacy of the existing therapeutic regimen against new SARS-CoV-2 variants.

Genome sequencing of SARS-CoV-2 reveals the prevalence of variant B 1.1.7 in Egypt

Recently, the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) resulted in Coronavirus Disease 2019 (COVID-19) outbreak. A new SARS-CoV-2 strain is expected to emerge in late 2020, including B.1.1.7. The high transmission rate of SARS-CoV-2 B.1.1.7 has raised public health concerns in several countries. Hence, in this study, we assessed the sequencing of SARS-COV2 to reveals the prevalence of the SARS-CoV-2 Alpha variant (B 1.1.7) in Egypt. We found that the viral transmission of the alpha variant is expanding. Moreover, based on hospitalizations and case fatality rates, there is a potential for increasing severity. There was no effect on susceptibility to Emergency Use Authorization monoclonal antibody treatments. However, there was minimal impact on neutralization by convalescent and post-vaccination sera. Samples have been clustered into the 20D sub clade for the majority of them. The eight samples shown in our study are considered the first recorded samples with the Alpha variant in Egypt. Therefore, The Egyptian government, represented by the Ministry of Health, must take all measures to examine the compatibility of the currently used vaccines with this new strain and the feasibility of the treatment protocol presently used with such strains developed in the Arab Republic of Egypt.

Physiological and behavioral responses of land molluscs as biomarkers for pollution impact assessment: A review

Environmental pollution caused by human activities is a global public health concern. This review discusses the impact of different types of pollutants such as pesticides, metals, nanoparticles and others on land molluscs. These molluscs are of great interest as good model organisms for studying biomarker responses in ecotoxicological monitoring programs. Several biomarkers are utilized to characterize and quantify the exposure and harmful impacts of various pollutants. In this review, we have identified physiological and behavioral endpoints (feeding, growth, avoidance, mucus secretion, locomotion and reproductive behavior) for the diagnosis of environmental pollution. The present review displays that all types of pollutants can disturb physiological and behavioral endpoints of gastropods, and these impacts depend on the matrix, exposure time and route as well as the type and concentration of the pollutants in the environment. We have also confirmed that terrestrial gastropods particularly snails as sentinel species could be used as potential bioindicator organisms for environmental quality assessment and thus for predicting potential hazards to human health.

Biomarker responses in terrestrial gastropods exposed to pollutants: A comprehensive review

The chemical contamination of terrestrial ecosystems is a great concern as these ecosystems are the target of most of the pollutants derived from anthropogenic activities such as pesticides, heavy metals, nanoparticles, and others. Terrestrial gastropods are considered to be excellent sentinel organisms for biological monitoring of environmental pollution, as they have the ability to accumulate chemicals in their tissues and exhibit a great potential to evaluate the ecological effects of pollutants in terrestrial ecosystems. The use of biomarkers as sensitive parameters to estimate the exposure or resulting effects of chemicals have received considerable attention. The successful biomarker must be applicable in the laboratory and field conditions. Many biomarkers have been examined to understand the adverse effects of pollutants. In this review, we shed light on different types of biomarkers, such as oxidative stress, genotoxicity and immunotoxicity as diagnostic tools for monitoring the impacts of pollution. These biomarkers can provide information about early detection and quantification of these impacts during their initial manifestations and can facilitate the implementation of a rapid preventive and/or restorative responses in the affected ecosystems, as well as single or multiple biomarkers can be integrated into routine monitoring programs.

Use of multiple endpoints to investigate the ecotoxicological effects of abamectin and thiamethoxam on Theba pisana snails

The ecotoxicological effects of dietary exposure to sublethal concentration (1/20 LC₅₀) of abamectin (ABM) and thiamethoxam (TMX) for two weeks exposure and one week recovery on oxidative stress parameters; lipid peroxidation (LPO), reduced glutathione (GSH), catalase (CAT) and glutathione S-transferase (GST), Deoxyribonucleic acid (DNA) damage as well as immunological parameters; cell death, phagocytosis, lysosomal membrane stability (LMS), lectins, superoxide anion (O₂^-) generation, phenoloxidase (PO), peroxidase (POD) and hemocyanin (Hc) of the land snail, Theba pisana were examined. The results showed that both tested compounds significantly increased DNA damage, LPO content, the activity of CAT and GST, cell death, POD activity, Hc level, whereas, significantly declined in phagocytic activity, LMS, lectins level, O2^- generation, PO activity, and GSH content compared to the controls after two week exposure. After one week of recovery, the measured biochemical parameters of treated snails were slightly repaired but their levels were still less than that of the level of untreated animals. Overall, based on acute toxicity endpoints, ABM appeared to be more harmful than TMX against this animal. Indeed, the different patterns of endpoint responses could represent a useful picture to characterise exposure to these pesticides in the land snail, T. pisana. This battery of snail endpoints might be a promising option to biomonitor the health of the terrestrial ecosystem and to offer valuable insights to the pesticides toxicity mechanisms.

Feeding and growth responses of the snail Theba pisana to dietary metal exposure

The effects of dietary exposure to copper (Cu), lead (Pb), and zinc (Zn) on feeding activities, growth response, and mortality of Theba pisana snails were studied in 5-week feeding tests. Snails were fed on an artificial diet containing the following Cu, Pb, or Zn concentrations: 0, 50, 100, 500, 1000, 5000, 10,000, and 15,000 μg/g dry food. At the end of 5 weeks, the food consumption rate was decreased with increasinges in both metal concentrations and time of exposure. The estimated concentrations of metals that reduces food consumption to 50% (EC₅₀) after 5 weeks were 56, 118, and 18 μg/g dry food for Cu, Pb, and Zn, respectively. All tested metals in the diet were found to inhibit growth of the snails in a dose-dependent manner. The toxic effect on growth of the tested metals could be arranged in the order Cu > Zn > Pb. The cumulative percentage mortality among snails fed a Cu- or Zn-contaminated diet was 73.3% and the respective value for a Pb-contaminated diet was 13.3%. There was a positive correlation between growth coefficient and food consumption for all tested metals.

Oxidative stress biomarkers in the digestive gland of Theba pisana exposed to heavy metals

The in vivo toxic effects of sublethal treatment of 40 and 80% of 48-h LD(50) of topically applied trace metals [copper (Cu), lead (Pb), and zinc (Zn)] on oxidative stress biomarkers in the digestive gland of Theba pisana were examined. Oxidative individual perturbations were assessed by measuring nonenzymatic (glutathione; GSH) and enzymatic (catalase, CAT; glutathione peroxidase, GPx; and glutathione-S-transferase, GST) antioxidants in digestive gland of the snails. Lipid peroxidation (LPO) was also evaluated as a marker of cell damage. The results indicated that the copper ion was the most potent metal against this snail, followed by zinc and lead, for which the corresponding LD(50) values were 37.88, 261.72, and 652.55 microg/snail, respectively. The no-observed effect concentration (NOEC) values for Cu, Zn, and Pb were 10, 50, and 500 microg/snail, respectively, and the corresponding lowest-observed effect concentration (LOEC) values were 50, 100, and 1000 microg/snail. All trace metals resulted in a significant increase in the level of LPO, whereas a significant decline in the content of GSH was observed when compared with untreated controls. Treatment with both sublethal doses of the metals caused significant increase in CAT activity, except in the case of 40% LD(50) Zn and 80% LD(50) Cu, which exhibited no alteration in CAT when compared to control animals. GPx was significantly increased in snails exposed to 40% LD(50) Cu and Pb as well as 80% LD(50) Cu. However, an opposite effect was observed in snails exposed to 80% LD(50) Pb and in either 40 or 80% LD(50) of Zn-intoxicated animals. Treatment with Pb at two sublethal doses significantly increased GST activity, whereas treatment the animal with Cu caused significant inhibition in this enzyme. Snails exposed to 40% LD(50) Zn showed significant enhancement of GST, whereas snails exposed to 80% LD(50) showed significantly reduced GST activity. Biphasic responses were observed for CAT, GPx, and GST activities in snails exposed to Cu, Pb, and Zn, respectively. This study suggests that upregulation of the antioxidant enzyme activities, elevation of LPO, and the reduction in GSH content is related to oxidative stress in this species that could be useful as biomarkers for the evaluation of contaminated terrestrial ecosystems.

Biomarkers of oxidative stress in the land snail, Theba pisana for assessing ecotoxicological effects of urban metal pollution

This study investigates the biomarkers of oxidative stress and heavy metal accumulation for assessing ecotoxicological effects of urban metal pollution in Alexandria city, Egypt. This investigation was performed in the digestive gland of roadside Theba pisana snails obtained from six different sites in the city. Relationships between heavy metal (Zn, Cu, Pb and Cd) concentrations and oxidative stress indicators were also examined. The results showed that mean concentrations of the measured elements (mugg(-1) dry weight) were higher in polluted sites when compared to the background levels of the reference site. The pattern of metals accumulation at all sites was Zn>Cu>Pb>Cd. In the metal polluted sites, snails displayed higher mean of catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase (GST) activities, lower reduced glutathione (GSH) content and higher levels of lipid peroxidation (LPO) compared to snails from the reference site. All oxidative stress parameters were positively correlated to heavy metal concentrations except GSH content which exhibits negative correlation with the concentrations of these metals. Our results suggest that the tested antioxidant defenses are sensitive parameters that could be useful as oxidative stress biomarkers in snails exposed to the actual metals in the environment. These biomarkers when complemented with metal accumulation in the digestive gland of snails may provide a powerful biomonitor for the assessment of environmental metal pollution.

In vivo evaluation of oxidative stress biomarkers in the land snail, Theba pisana exposed to copper-based pesticides

The in vivo evaluation of oxidative stress biomarkers in the digestive gland of Theba pisana exposed to sublethal doses (40% and 80% of LD(50) after 48 h) of copper-based pesticides; copper oxychloride, copper hydroxide and copper sulphate was examined. Oxidative individual perturbations were assessed by measuring non-enzymatic (glutathione; GSH) and enzymatic (catalase; CAT, glutathione peroxidase; GPx and glutathione S-transferase; GST) antioxidants in digestive gland of the snails. Lipid peroxidation (LPO) was also evaluated as marker of cell damage. The results indicated that copper sulphate was the most potent compound against this snail followed by copper hydroxide and copper oxychloride where their corresponding LD(50) values were 26.54, 334.54 and 582.18 microg snail(-1), respectively. Copper-based compounds resulted in a significant increase in the level of LPO whereas a significant decline of GSH content in the digestive gland of snails was observed when compared with untreated controls. The CAT, GPx and GST activities of treated snails were significantly higher than those of untreated controls. In general, the activation power of these compounds was in the following order: copper sulphate > copper hydroxide > copper oxychloride. This study suggests that up-regulation of the antioxidant enzyme activities, elevation of LPO and the reduction of GSH content is related to oxidative stress in this species that they could be used as potential biomarkers of copper-based pesticides exposure.