Microbial and copper adsorption by smectitic clay--an experimental study

Virological evaluation of natural and modified attapulgite against porcine epidemic diarrhoea virus

BACKGROUND

The Porcine Epidemic Diarrhea Virus (PEDV) has caused significant economic losses in the global swine industry. As a potential drug for treating diarrhea, the antiviral properties of attapulgite deserve further study.

METHODS

In this study, various methods such as RT-qPCR, Western blot, viral titer assay, Cytopathic Effect, immunofluorescence analysis and transmission electron microscopy were used to detect the antiviral activity of attapulgite and to assess its inhibitory effect on PEDV.

RESULTS

When exposed to the same amount of virus, there was a significant decrease in the expression of the S protein, resulting in a viral titer reduction from 10-5.613 TCID50/mL to 10-2.90 TCID50/mL, which represents a decrease of approximately 102.6 folds. Results of cytopathic effect and indirect immunofluorescence also indicate a notable decrease in viral infectivity after attapulgite treatment. Additionally, it was observed that modified materials after acidification had weaker antiviral efficacy compared to powdered samples that underwent ultrasonic disintegration, which showed the strongest antiviral effects.

CONCLUSION

As a result, Attapulgite powders can trap and adsorb viruses to inhibit PEDV in vitro, leading to loss of viral infectivity. This study provides new materials for the development of novel disinfectants and antiviral additives.

Geophagia: Benefits and potential toxicity to human—A review

Geophagy is the habit of consuming clay soil such as chalk or kaolin. Though it is globally practiced, the safety of those involved is yet to be fully established. It is thought to be highly prevalent in pregnant women because of its antinausea or therapeutic effects. This practice is also thought to be provoked by some nutritional needs, but in modern society its etiology is obscure. The mineralogical and chemical compositions of clay may vary from one region to another and even in all form of rocks clay constitutes. Published articles in geophagy indicate lack of adequate investigations into the toxicity of geophagy, though it is globally practiced and more prevalent in Africa (as a continent) or in Africans migrants. Some studies have helped to identify some minerals that are toxic to human if ingested. In most cases, the potential toxicity emphasized by these studies is based on the detection of the presence of these nuisance elements in the geophagic materials. Scientifically, a lot has been done in the light of detection of toxic matter, but more investigations on metabolic studies are still necessary. The variability of clay content with respect to source motivated this review on geophagy and its potential toxicity to human. This review is aimed at bringing out findings that would enable a better understanding of the toxicity potential of geophagy across context and taxa.

Dietary Kaolin Clay in Pre- and Post-Weaned Piglets and Its Influence on Haematological and Biochemical Parameters, and Intestinal Microflora Status

The main aim of the study was to evaluate the effect of two experimental feed additives based on kaolin clay on piglets’ health and microbiota status. The experiment was divided into 2 parts – from birth up to weaning (28 d) and later after weaning up to 70 d of age. Eighteen litters of piglets with sows were divided into 3 groups: control, A and B. The animals from experimental group A were supplemented with kaolin clay (100%), while the animals from group B received kaolin clay enriched with dried pomace of chokeberry and fructooligosaccharides. We noted an improvement in blood parameters related to anaemia, which were significantly better in the experimental group B in comparison to the control and A group (haematocrit; 37.67 and 37.40 vs 39.65%; P<0.0005). The dietary treatments during pre-weaning time influenced the increase of the E. coli strain in the colon and jejunum and had no effect on lowering the population of Salmonella and Shigella in the colon. However, it affected the quantity of Salmonella and Shigella in the jejunum in both A and B (-20%) groups. The rise of commensal bacteria Lactobacillus (+2.3 and +10%) and Bacteroides (+5.82 and +5.11%) was observed in groups A and B in the colon. This effect was not present in the jejunum.

Kaolin incorporated diet on growth and immune response in Ctenopharyngodon idellus against Aeromonas hydrophila

The effect of kaolin enriched diet on growth, hematology, and immune response in the grass carp Ctenopharyngodon idellus against Aeromonas hydrophila is reported. Both the infected and uninfected groups fed with kaolin enriched diet gained better weight, protein efficiency ratio (PER) and feed conversion ratio (FCR). The survival rate was 98.3% in control (C) and uninfected (UI) fed with 2 g kg^-1 kaolin diet, whereas it was 95.0% in uninfected (UI) fed with 1 g kg^-1 or infected (I) fed with 1 g kg^-1 kaolin diets. In both groups the red blood cell (RBC) and white blood cell (WBC) counts, percentage of lymphocytes and eosinophils, level of albumin and globulin increased in uninfected (UI) fed with 1, 2, and 3 g kg^-1 diets. The serum Ig level significantly increased in both groups when fed with 3 g kg^-1 diet, whereas the phagocytic activity did not increase significantly. Further the respiratory burst activity in both groups significantly increased with any supplemented diet. The serum superoxide dismutase (SOD) activity increased significantly in the infected group fed with 2 g kg^-1 diet and the uninfected group fed with 1 g kg^-1 diet. The complement activity was significantly enhanced in both groups when fed with 1 and 2 g kg^-1 diets; the lysozyme activity increased with 2 g kg^-1 diet; besides the group was 5% mortality whereas 10% mortality was observed when fed with 1 or 3 g kg^-1 diets. The present results suggest that C. idellus fed with kaolin enriched diet promotes growth, hematology, innate and adaptive immune response against Aeromonas hydrophila infection.

Detection of Aichi virus genotype B in two lines of wastewater treatment processes

Enteric viruses are released in important quantities into the environment where they can persist for a very long time. At very low doses, they can cause human gastroenteritis, and are responsible for a substantial number of waterborne diseases. The aims of this study were multiple: firstly, to study the circulation of Aichi viruses (AiV) in wastewater sampled at the scale of a pilot wastewater treatment plant; secondly, to evaluate the performance of two wastewater treatment procedures, as natural oxidizing lagoons and rotating Biodisks, concerning the AiV removal; and finally, to determine the different type of AiV genotype found during this study. Hence, the pilot wastewater treatment plant is principally irrigated by the wastewater of three neighbouring clinics. Wastewater samples were collected during 2011 from the two lines of biological treatment procedures. AiV detection in wastewater were achieved using the Reverse Transcription Polymerase Chain Reaction (RT-PCR) technique, and the identification of AiV genotype was realized by the direct sequencing of PCR products. The result revealed that AiV strains were identified in 50% (n = 51) of the wastewater samples. A significant increase of the AiV detection frequency was registered from upstream to downstream of the five ponds constituting the natural oxidizing lagoon process, and at the exit of the rotating Biodisks procedure. All detected AiV strains showed the highest nucleotide sequence identity to genotype B that has been recently observed in patients in Asia. This finding represented the first Tunisian survey that revealed and mentioned the first detection of AiV genotype B in sewage and by the same argued for a noticeable resistance or survival of this type of virus in the two lines of treatment considered.

The addition of modified attapulgite reduces the emission of nitrous oxide and ammonia from aerobically composted chicken manure

The acceleration of the composting process and the improvement of compost quality have been explored by evaluating the efficacy of various additives, inoculating with specific microorganisms and the application of various biosurfactants. The magnesium-aluminum silicate attapulgite is a low-cost potential composting additive, but its effects on aerobic composting are unknown. This study investigated the effects of attapulgite application on compost production and quality during the aerobic composting of chicken manure. Addition of attapulgite significantly increased the temperature (p < 0.05) while it reduced compost total organic carbon (TOC) and seed germination indices (GIs) throughout the process. Its addition enhanced nitrate concentrations, promoted organic matter degradation, increased seed germination indices, and accelerated the composting process. Interestingly, attapulgite addition did not increase the population of ammonia-oxidizing bacteria. These results suggest that attapulgite is a good additive for the composting industry.

IMPLICATIONS

We investigated the addition of two forms of attapulgite during aerobic composting of chicken manure to determine their effects under strict composting environmental parameter control. Our results provides primary evidence that attapulgite may have potential for application in the composting industry. All treatments showed no increase within the first 15 days. However, emissions increased for all treatments within 15-45 days, reaching approximately 6300, 2000, and 4000 mg/m2 from the control, artifactitious attapulgite, and raw attapulgite treatments, respectively.

Effects of intestinal intervention on bacterial translocation in a rat model of acute liver failure in vivo

BACKGROUND/AIMS

The study aimed to confirm bacterial translocation (BT) in rats with acute liver failure (ALF), to explore the correlation between the concentration of lipopolysaccharides and Toll-like receptor 4 (TLR4) expression, and further, to evaluate the curative effects of lactulose and montmorillonite (smecta) in this setting.

METHODS

D-Galactosamine was injected into the abdominal cavity of rats to induce ALF. Escherichia coli JM109 labeled with enhanced green fluorescent protein was administered to track BT. Simultaneously, the rats were given lactulose or smecta. Blood samples were collected for measuring liver function, cytokines, endotoxins, and TLR4 expression. Representative tissue specimens from the liver, spleen, and mesenteric lymph nodes were aseptically harvested for bacterial identification by agarose gel electrophoresis, laser scanning confocal microscopy, and flow cytometry.

RESULTS

BT occurred in ALF, accompanied by impaired liver function with increased cytokines, endotoxins, and TLR4 expression. After the treatment with lactulose or smecta, all these parameters decreased, including the relative quantity of translocated bacteria while albumin increased. Furthermore, compared with the lactulose treatment group, the parameters in the smecta treatment group improved. Moreover, in the group in which smecta was given for prophylaxis, there was greater improvement than with treatment.

CONCLUSION

Intestinal intervention with lactulose or smecta can ameliorate BT; moreover, smecta has a better effect than lactulose, and its preventive effect was also better than its therapeutic effect.

Removal of sulphur dioxide using palygorskite in a fixed bed adsorber

This work describes the use of a novel palygorskite, a type of magnesium aluminium silicate clay possessing a high specific surface area and pore surface activity, as a low cost and highly efficient adsorbent for sulphur dioxide (SO2) removal. Dynamic adsorption in a fixed bed adsorber showed that palygorskite pretreated with sodium hydroxide had a higher adsorption capacity at 10% breakthrough than either raw material or that pretreated with acid. The SO2 adsorption capacity increased with increasing inlet SO2 concentration and decreased with increasing temperature. Samples were characterized for: specific surface area using the Brunauer-Emmett-Teller (BET) method, crystal structure by X-ray diffraction (XRD), and surface chemistry by Fourier transform infrared spectroscopy (FTIR). Adsorption equilibrium isotherms were established for samples over an SO2 concentration range from 50 to 460 ppm, at room temperature. The adsorption equilibrium could be described by both the Freundlich and the Langmuir isotherms.

Effects of smectite clay on biofilm formation by microorganisms

We have investigated the role of smectite clay particles in biofilm formation by several different species of bacteria (Pseudomonas syringae, Escherichia coli,Staphylococcus aureusandBacillus subtilis). We observed that the presence of clay particles enhances the formation of biofilms and, after 24 h, the bacterial populations in the clay mixtures were greater than the respective populations in media without clay. Smectite-bearing clay slurries uniformly develop bacteria–clay aggregates with a substantial biofilm component within 24 h, while the exclusively bacterial suspensions do not develop any observable biofilm component. The biofilm–clay aggregates vary in size from tens of micrometers to several millimeters. Biofilm formation was evaluated by phase contrast microscopy and fluorescence staining. Biofilm promotion by smectite clays may indicate the importance of transport of bacteria by aerosol dust particles.