Total coliphages removal by activated sludge process and their morphological diversity by transmission electron microscopy.

This study was conducted to isolate phages in treated sewage collected from wastewater treatment plant, and explore their morphological diversity by transmission electron microscopy (TEM). Fates of total bacteriophages and their reduction by biological treatment were also assayed. Phages were isolated using the plaque assay then negatively stained and observed by electron microscope. Electron micrographs showed different types of phages with different shapes and sizes. The majority of viruses found in treated sewage ranged from 30 to 100 nm in capsid diameter. Many of them were tailed, belonging to Siphoviridae, Myoviridae and Podoviridae families. Non-tailed phage particles were also found at a low rate, presumably belonging to Leviviridae or Microviridae families. This study shows the diversity and the abundance of bacteriophages in wastewater after biological treatment. Their persistence in wastewater reused in agriculture should raise concerns about their potential role in controlling bacterial populations in the environment. They should be also included in water treatment quality controlling guidelines as fecal and viral indicators.

Effect of White Kidney Beans (Phaseolus vulgaris L. var. Beldia) on Small Intestine Morphology and Function in Wistar Rats.

The chronic ingestion of raw or undercooked kidney beans (Phaseolus vulgaris L.) causes functional and morphological derangement in various tissues. The major objectives of this study were to investigate the gavage effects of a raw Beldia bean variety that is widely consumed in Tunisia, on the small intestine morphology and jejunal absorption of water, electrolytes, and glucose in Wistar rats. Twenty young male rats were randomly divided into two groups of 10 rats. The first group served as the control and was gavaged with 300 mg of a rodent pellet flour suspension (RPFS), whereas the second experimental group was challenged with 300 mg of a Beldia bean flour suspension (BBFS) for 10 days. Histological studies were performed using light and electron microcopy. The intestinal transport of water, sodium, potassium, and glucose was studied by perfusing the jejunal loops of the small bowels in vivo. The feeding experiments indicated that BBFS did not affect weight gain. Histomorphometric analyses showed that the villus heights, crypt depths, and crypt/villus ratios in the jejunum and ileum were greater in the BBFS-fed rats than controls. Electron microscopy studies demonstrated that the rats exposed to RPFS exhibited intact intestinal tracts; however, the BBFS-treated rats demonstrated intestinal alterations characterized by abnormal microvillus architectures, with short and dense or long and slender features, in addition to the sparse presence of vesicles near the brush border membrane. BBFS administration did not significantly affect glucose absorption. However, significant decreases were observed in water and electrolyte absorption compared with the uptake of the controls. In conclusion, raw Beldia beans distorted jejunum morphology and disturbed hydroelectrolytic flux.

Comparison of the intracellular behavior of gold (Au) and indium (In) in testicle after their parenteral administration.

The subcellular behavior of several mineral elements was studied using modern techniques of observation like transmission electron microscopy and analysis like electron probe microanalysis and secondary ion mass spectrometry. In the present ultrastructural and analytical investigations, we undertake to compare the intracellular behavior of a heavy metal, gold, and a III-A group element, indium, on rat testicular tissues after their parenteral administrations. Our ultrastructural results showed that while gold was found only in the lysosomes of Leydig cells under electron dense needles, indium was observed as electron-dense deposits in the lysosomes of both Leydig and Sertoli cells. No ultrastructural modifications were observed in the testicular tissues of the control rats. The microanalytical study showed that gold was concentrated in lysosomes with sulfur as a sulfate crystalline structure whereas indium was concentrated in the same organelle as insoluble phosphate salt. These results demonstrated that testicular Leydig and Sertoli cells have the ability to selectively concentrate indium but gold was concentrated only in the first kind of cells. The mechanism implicated in this concentration phenomenon is a biochemical one involving intralysosomal hydrolytic enzymes, the acid phosphatase and the arylsulfatase. This mechanism occurs in order to protect the organism and to avoid the presence of toxic metals under soluble and free form.

Role of parietal and principal gastric mucosa cells in the phenomenon of concentration of aluminum and indium.

The subcellular behavior of aluminum and indium, used in medical and industrial fields, was studied in the gastric mucosa and the liver after their intragastric administration to rats, using, two of the most sensitive methods of observation and microanalysis, the transmission electron microscopy, and the secondary ion mass spectrometry. The ultrastructural study showed the presence of electron dense deposits, in the lysosomes of parietal and principal gastric mucosa cells but no loaded lysosomes were observed in the different studied hepatic territories. The microanalytical study allowed the identification of the chemical species present in those deposits as aluminum or indium isotopes and the cartography of their distribution. No modification was observed in control rats tissues. In comparison to previous studies describing the mechanism of aluminum concentration in the gastric mucosa and showing that this element was concentrated in the lysosomes of fundic and antral human gastric mucosa, our study provided additional informations about the types of cells involved in the phenomenon of concentration of aluminum and indium, which are the parietal and the principal cells of the gastric mucosa. Our study demonstrated that these cells have the ability to concentrate selectively aluminum and indium in their lysosomes, as a defensive reaction against intoxication by foreign elements.

Microscopy and microanalysis study of the indium (In) behavior in the intestinal mucosa, the liver, the kidney and the testicle.

Several studies have demonstrated that In used in medicine has several impacts on organs like spleen and lungs after its systemic administration. In the present study, ultrastructural and microanalytical methods were used to investigate the impact of the presence of this element in the intestinal mucosa, the liver, the kidney and the testicle after its administration in two ways. After intraperitoneal administration, In was selectively concentrated in the lysosomes of hepatocytes, of tubular proximal convoluted cells and of Sertoli and Leydig cells. After intragastric administration, ultrastructural study showed that this element was concentrated in the lysosomes of duodenal enterocytes. Microanalytical methods showed that In was precipitated in those organelles in the form of insoluble phosphate salts. Similarly to other studies, it seemed that since In is a foreign element for the organism, it was precipitated in lysosomes, very probably due to the activity of an intralysosomal enzyme the acid phosphatase, to avoid its invasion to organism via the blood. This mechanism of precipitation of the mineral elements is of great interest in the process of defensive reaction of the organism against intoxication by foreign elements.

[Vitamin A effects on morphometric adaptation after extensive small bowel resection in the rat]. / Effets de la vitamine A sur les adaptations morphométriques après résection étendue de l'intestin grêle du rat.

This work was conceived to study, in the rat short bowel syndrome, the effect of precocious administration of retinoic acid on morphometric adaptation in the remnant intestine. Mitotic index, villous height, crypt depth and mucosal aspect were determined in 2 groups of rats (n=12) after 60% small bowel resection. 100 microg of retinoic acid were perfused immediately after resection in the first group. Control group rats received placebo. Two similar groups (n=12) underwent intestinal transection with or without retinoic acid perfusion. Our results show that retinoic acid induced precocious and significant enhancement of all morphometric parameters when compared to placebo.