Lysozyme as a local defense factor in the gastrointestinal tract of patients with chronic diseases of the digestive organs]

No microbial growth in platings of the gastric juice of patients with gastric ulcer and chronic anacidic gastritis was observed. It means that the absence of hydrochloric acid in the gastric juice does not deprive it of any antimicrobial action. The possible role of lysozyme in providing sterility of the proximal part of the gastro-intestinal tract was studied. Eighty patients with chronic diseases of the digestive organs were observed. It was noted that the levels of lysozyme in the gastric juice was high and markedly exceeded the maximum concentrations required for lysis of organisms most resistant to it. The maximum concentration was determined at pH of the gastric juice equal to 7.0-7.5 (265 gamma/ml+/-28). No lysozyme in the content of the duodenum and jejunal juice was found in most cases. Its presence in the above parts of the gastro-intestinal tract was mainly associated with microbial growth. The maximum concentration of lysozyme (40 gamma/ml) in the jejunal juice was observed in a female patient with chronic enterocolitis and significant microbial proliferation in the thin colon (more than 10(4) microbial bodies per 1 ml of the juice). Such parallelism between the presence of lysozyme in the gastric juice and microbial proliferation in it may be considered as a protective-adoptive reaction of the host.     

Electron microscope studies of the digestive tract ofBrachionus plicatilis (Rotifera)

Summary The rotiferBrachionus plicatilis was immobilized in an extended state by treatment with acrylamide. Longitudinal sections through whole animals were studied by transmission electron microscopy, and in addition animals were cut in different planes and studied by scanning electron microscopy. By these techniques several structures were characterized which seem to be relevant to the processes of enzymatic digestion and resorption in this species. The inner surfaces of both the stomach and the intestine are provided with rootless cilia, which show different densities, alignments, structures and properties in different compartments. The syncytial wall of the anterior part of the stomach is flat; its plasma membrane toward the stomach lumen is smooth and bears relatively few cilia. The posterior part of the stomach consists of voluminous cells. Their plasma membranes lining the stomach cavity show pits and infoldings that are continuous with a system of vacuoles within the cells containing membrane material probably derived from food organisms. The density of cilia in the posterior part of the stomach is about three times that in the anterior part. The stomach glands contain ribosomes, glycogen granules and secretory bodies, which are accumulated toward the region where these glands drain into the stomach cavity. The orifice of the stomach glands occurs in a permanent intercellular gap between the syncytial anterior stomach and three cells of the posterior part of the stomach. The cells of the intestinum are relatively flat and are characterized by mitochondria, narrow intercellular spaces between shingle-like overlapping wall cells and cilia differing in structure and properties from those of the stomach. The observations confirm the existence of functional differences between stomach and intestine. Digestion of nutrients, supported by secretions of the stomach glands, seems to be performed mainly within the stomach, and resorption of particulate food seems to occur almost exclusively in this part of the alimentary tract. The structural features of the intestine, on the other hand, indicate that small molecules may be transported through its wall and that here, perhaps, processes may take place which demand active transport.Abbreviations ast anterior part of the stomach - bm basal membrane toward pseudocoel - cb cell border between stomach cells - cwh rooted cilia of the wheel organ - dm desmosome structure between intestinum cells - e esophagus - gc glycocalyx (fuzzy coat) - gl gastric gland - isp intercellular space - it intestinum - itl intestinum lumen - m mitochondrion - mbl membranelles in the esophagus - mx mastax - pc pseudocoel - pst posterior part of the stomach - sb secretory bodies - SEM scanning electron microscopy - st stomach - stl stomach lumen - TEM transmission electron microscopy - v (food-) vacuole in cells of the posterior stomach wall - x small vesicle or grana-like structures on the lumen side of the opening of the gastric gland Dedicated to Dr. h.c. Walter Koste on the occasion of his 80th birthday     

Bioengineering of the digestive tract: approaching the clinic

The field of regenerative medicine is developing technologies that, in the near future, will offer alternative approaches to either cure diseases affecting the gastrointestinal tract or slow their progression by leveraging the intrinsic ability of our tissues and organs to repair after damage. This article will succinctly illustrate the three technologies that are closer to clinical translation—namely, human intestinal organoids, sphincter bioengineering and decellularization, whereby the cellular compartment of a given segment of the digestive tract is removed to obtain a scaffold consisting of the extracellular matrix. The latter will be used as a template for the regeneration of a functional organ, whereby the newly generated cellular compartment will be obtained from the patient's own cells. Although clinical application of this technology is approaching, product development challenges are being tackled to warrant safety and efficacy.     

Bifidobacteria in the digestive tract of bumblebees

Bifidobacteria and other bacterial groups (lactobacilli, facultative anaerobes, anaerobes) from the digestive tract of three bumblebee species (Bombus lucorum (34 samples), Bombus pascuorum (18 samples) and Bombus lapidarius (9 samples)) were enumerated and characterised. Counts of facultative anaerobic bacteria and lactobacilli (5.41 ± 2.92 and 2.69 ± 3.02 log CFU/g of digestive tract content) were lower than those of anaerobes (7.66 ± 0.86 log CFU/g). Counts of bifidobacteria were determined using two selective media: MTPY (Modified Trypticase Phytone Yeast extract agar) and a new medium with pollen extract. There was no significant difference between the counts of bifidobacteria from both media, 5.00 ± 2.92 log CFU/g on MTPY and 5.00 ± 2.87 on the pollen medium. Subsequently, 187 bacterial strains of the family Bifidobacteriaceae (fructose-6-phosphate phosphoketolase-positive) were isolated from three different localities and from all three species of bumblebees. Bifidobacteria were found in 42 out of 61 specimens (69%). Twenty-three (38%) specimens had counts of bifidobacteria higher than 7.0 log CFU/g. Bifidobacteria represented the dominant group of anaerobes (>70% of total anaerobes), i.e., the principal group of bacteria in the bumblebee digestive tract, in only fourteen specimens (23% of total). For the first time, bifidobacteria were isolated from the digestive tract of bumblebees. In addition, we suggest, on the basis of biochemical tests (API 50 CHL and RAPID ID 32) and genetic methods (PCR and DGGE), that these bacteria may represent new species within the family of Bifidobacteriaceae.     

Carbohydrase activities in the bovine digestive tract

1. The carbohydrase activities of homogenates of mucosa from the abomasum, small intestine, caecum and colon, and of the pancreas of cattle were studied. 2. The disaccharidase activities were located mainly in the small intestine and showed a non-uniform pattern of distribution along the small intestine; trehalase activity was highest in the proximal part, lactase and cellobiase activities were highest in the proximal and middle parts and maltase activity was highest in the distal part. 3. The intestinal lactase and cellobiase activities were highest in the young calf and decreased with age, whereas the intestinal maltase and trehalase activities, which were very low compared with the lactase activity, did not change with age. 4. No intestinal sucrase or palatinase activity was detected in the calf or in the adult cow. 5. Homogenates of intestinal mucosa also exhibited amylase and dextranase activity. 6. Homogenates of the pancreas possessed a strong amylase activity and a weak maltase activity. The maltase activity did not change with age, whereas the amylase activity increased with age. 7. No marked differences were observed between the carbohydrase activities of calves fed solely on milk and those of calves given a concentrate-hay diet from 6 weeks of age.     

Lactic bacteria in the digestive tract of poultry

Lactic bacteria predominate in the microflora of the digestive tract of chicken and turkey. They are represented mainly by Lactobacillus acidophilus, L. salivarius, L. fermentum and L. buchneri. Streptococcus faecium is always isolated. L. ruminis, L. vitulinus, L. delbrueckii, L. coryniformis and L. viridescens were found in this ecological niche for the first time. S. faecium and S. faecalis prevail in the digestive tract of geese and ducks, while lactobacilli are detected in a lesser amount and are represented mainly by L. plantarum. L. salivarius cells isolated from the digestive tract of poultry are highly polymorphous. Most of the lactic acid bacteria found in the digestive tract of poultry can grow at 45-50 degrees C whatever is the species they belong to.     

Culturable microorganisms from the earthworm digestive tract

The cultured aerobic copiotrophic bacteria and fungi from food-free digestive tracts of Aporrectodea caliginosa, Lumbricus terrestris, and Eisenia fetida earthworms, soil (compost), and fresh earthworm excrements were investigated. The microorganisms were isolated on nutrient media and identified by sequencing the fragments of bacterial 16S rRNA and fungal 28S rRNA (D1/D2 domain) gene sequences with subsequent phylogenetic analysis. Bacteria isolated from the digestive tracts of earthworms belonged to the families Aeromonadaceae, Comamonadaceae, Enterobacteriaceae, Flavobacteriaceae, Moraxellaceae, Pseudomonadaceae, and Sphingobacteriaceae (Bacteroidetes), as well as Actinobacteria. For five strains, namely Ochrobactrum sp. 341-2 (α-Proteobacteria), Massilia sp. 557-1 (β-Proteobacteria), Sphingobacterium sp. 611-2 (Bacteroidetes), Leifsonia sp. 555-1, and a bacterium from the family Microbacteriaceae, isolate 521-1 (Actinobacteria), the similarity to known 16S rRNA sequences was 93–97%; they therefore, probably belong to new species and genera. Bacterial groups isolated from the digestive tracts of earthworms were significantly different from those isolated from soil and excrements. Some bacterial taxa occurred in different sections of A. caliginosa intestine and in intestines of different earthworm species; however, the overall composition of bacterial communities in these objects is different. Existence of bacterial groupings symbiotically associated with intestines is proposed. Among the fungi, Bjerkandera adusta and Syspastospora parasitica were isolated from the cleaned digestive tracts as light-colored, sterile mycelium, as well as Geotrichum candidum, Acremonium murorum (A. murorum var. felina), Alternaria alternata, Aspergillus candidus, A. versicolor, Cladosporium cladosporioides, Rhizomucor racemosus, Mucor hiemalis, Fusarium (F. oxysporum, Fusarium sp.), and Penicillium spp. These fungi survive for a long time in the earthworm’s digestive environment. Investigation of the functional characteristics and role in the host organism is required to confirm the symbiotic status of the microorganisms associated with the earthworm digestive tract.     

Chitinolytic bacteria of the mammal digestive tract

Chitinolytic bacteria were isolated from the digestive tract of different mammals and characterized. All isolates were facultatively anaerobic, long Gram-positive, straight rods resemblingClostridium sp. Only one isolate consisted of Gram-positive ovoid cells. All cultures grew on glucose,N-acetylglucosamine, glucosamine, galactose, starch, hemicellulose and xylan. Fermentation products were mainly formate, acetate, butyrate and lactate. The isolates were identified asClostridium sartagoforme (2 species),C. aminovalericum, C. bifermentans andEnterococcus durans (1 isolate of each species). Exocellular fractions of all strains exhibited higher activities of all enzymes than cellular ones. Inductive effects of hemicelluloses, pectin and laminarine on chitinases were demonstrated. High exocellular endochitinase activity was found in cultures grown on chitin.N-Acetylglucosaminidase activity was low with the exception of exocellular fractions of two strains ofC. sartagoforme.