Preventive and therapeutic administration of an indigenous <Emphasis Type="Italic">Lactobacillus</Emphasis> sp. strain against <Emphasis Type="Italic">Proteus mirabilis</Emphasis> ascending urinary tract infection in a mouse model

Probiotics are increasingly being considered as non-pharmaceutical and safe potential alternatives for the treatment and prevention of a variety of pathologies including urinary tract infections. These are the most common infections in medical practice and are frequently treated with antibiotics, which have generated an intense selective pressure over bacterial populations. Proteus mirabilis is a common cause of urinary tract infections in catheterised patients and people with abnormalities of the urinary tract. In this work we isolated, identified and characterised an indigenous Lactobacillus murinus strain (LbO2) from the vaginal tract of a female mouse. In vitro characterisation of LbO2 included acid and bile salts tolerance, growth in urine, adherence to uroepithelial cells and in vitro antimicrobial activity. The selected strain showed interesting properties, suitable for its use as a probiotic. The ability of LbO2 to prevent and even treat ascending P. mirabilis urinary tract infection was assessed using an experimental model in the mouse. Kidney and bladder P. mirabilis counts were significantly lower in mice preventively treated with the probiotic than in non-treated mice. When LbO2 was used for therapeutic treatment, bladder counts of treated mice were significantly lower although no significant differences were detected in P. mirabilis kidney colonisation of treated and non-treated animals. These results are encouraging and prompt further research related to probiotic strains and the basis of their effects for their use in human and animal health.     

Unusual intestinal lamellae in the nematode Rhabditophanes sp. KR3021 (Nematoda: Alloinematidae)

The free-living nematode Rhabditophanes sp. has recently been placed in a clade of animal parasites and may be a unique example of a reversal to a nonparasitic lifestyle. Detailed morphological analysis of the intestine reveals the unusual and unique structure of splitting microlamellae forming a meshwork with cavities along the entire intestinal tract. Secretion vesicles were observed along the whole tract and along the length of the lamellae. It is suggested that these lamellae are adaptations to a different digestive strategy where low food availability and a low absorption surface are compensated for by maximizing the nutrient uptake efficiency along the entire length of the intestine. The likely reversal to a free-living life cycle may have caused drastic changes in diet, providing the necessary driving forces to such morphological changes.     

Ventricle and outflow tract of the African lungfish Protopterus dolloi

We report a morphologic study of the heart ventricle and outflow tract of the African lungfish Protopterus dolloi. The ventricle is saccular and appears attached to the anterior pericardial wall by a thick tendon. An incomplete septum divides the ventricle into two chambers. Both the free ventricular wall and the incomplete ventricular septum are entirely trabeculated. Only a thin rim of myocardium separates the trabecular system from the subepicardial space. The outflow tract consists of proximal, middle, and distal portions, separated by two flexures, proximal and distal. The proximal outflow tract portion is endowed with a layer of compact, well-vascularized myocardium. This portion is homologous to the conus arteriosus observed in the heart of most vertebrates. The middle and distal outflow tract portions are arterial-like, thus being homologous to the bulbus arteriosus. However, the separation between the muscular and arterial portions of the outflow tract is not complete in the lungfish. A thin layer of myocardium covers the arterial tissue, and a thin layer of elastic tissue underlies the conus myocardium. Two unequal ridges composed of loose connective tissue, the spiral and bulbar folds, run the length of the outflow tract. They form an incomplete division of the outflow tract, but fuse at the distal end. The two folds are covered by endocardium and contain collagen, elastin, and fibroblast-like cells. They appear to be homologous to the dextro-dorsal and sinistro-ventral ridges observed during the development of the avian and mammalian heart. Two to three rows of vestigial arterial-like valves appear in the dorsal and ventral aspects of the conus. These valves are unlikely to have a functional role. The possible functional significance of the "gubernaculum cordis," the thick tendon extending between the anterior ventricular surface and the pericardium, is discussed.     

Metallothionein-like proteins and zinc-copper interaction in the hindgut of Porcellio scaber (crustacea: Isopoda) exposed to zinc

Metallothioneins (MTs) are ubiquitous low-molecular-weight metalbinding proteins, with a variety of functions in metal metabolism ascribed to them. Among terrestrial invertebrates, MTs have been studied in nematodes, insects, snails, and earthworms. The aim of this study was the characterization of MT-like proteins in the terrestrial isopod crustacean Porcellio scaber in order to analyze their probable role in the metaboliss of copper (Cu) and zinc (Zn). Dietary Zn supplementation (793 μg Zn/g dry food, 6 d) was applied to stimulate MT synthesis. After separation of the hindgut postmicrosomic supernatant (cytosol) of Zn-exposed animals by gel filtration on a Sephadex G-75 column, a Cu- and Zn-containing peak was detected in the position of V _c/V_o≈2, where MTs are expected to elute. Rechromatography of these fractions by size-exclusion chromatography-high-performance liquid chromatography revealed that the 215-nm absorbance peak coincided with the absorbance peak of the rabbit MT II standard. These low-molecular-weight Cu- and Zn-binding compounds, detected in the cytosol of the hindgut cells in Zn-exposed P. scaber. are considered to be Cu, Zn-MT-like proteins. To our knowledge, this is the first report on the characterization of MT-like proteins in isopod crustaceans. These results also indicate that both Zn and Cu dynamics in P. scaber hindgut are affected at the given dietary Zn supplementation and that MT-like proteins are involved in this Zn-Cu interaction.     

A-type cranberry proanthocyanidins and uropathogenic bacterial anti-adhesion activity

Clinical, epidemiological and mechanistic studies support the role of cranberry (Vaccinium macrocarpon Ait.) in maintaining urinary tract health. Cranberry proanthocyanidins contain A-type linkages and have been associated with preventing adhesion of P-fimbriated uropathogenic Escherichia coli to uroepithelial cells. It is not known if the presence of the A-type linkage is a prerequisite for anti-adhesion activity. Other commercial sources of proanthocyanidins with all B-type linkages have not previously been screened for this activity. The goals of this study were to compare the in vitro anti-adhesion activity of A-linked proanthocyanidins from cranberry juice cocktail with the anti-adhesion activities of B-linked proanthocyanidins from commercial grape and apple juices, green tea and dark chocolate, and determine if anti-adhesion activity is detectable in human urine following consumption of single servings of each commercial food product. Structural heterogeneity and presence of the A-type linkage in cranberry proanthocyanidins was confirmed utilizing MALDI-TOF/MS and DI/ESI MS, as was the presence of all B-type linkages in the proanthocyanidins from the other commercial products. The isolated A-type proanthocyanidins from cranberry juice cocktail elicited in vitro anti-adhesion activity at 60 microg/ml, the B-type proanthocyanidins from grape exhibited minor activity at 1200 microg/ml, while other B-type proanthocyanidins were not active. Anti-adhesion activity in human urine was detected following cranberry juice cocktail consumption, but not after consumption of the non-cranberry food products. Results suggest that presence of the A-type linkage in cranberry proanthocyanidins may enhance both in vitro and urinary bacterial anti-adhesion activities and aid in maintaining urinary tract health.     

Bifidobacterium-selective isolation and enumeration from chicken caeca by a modified oligosaccharide antibiotic-selective agar medium

AIMS: To determine the efficacy and selectivity of an acidified, antibiotic-selective, oligosaccharide-containing media for enumerating Bifidobacterium spp. from chicken caeca samples. METHODS AND RESULTS: Transoligosaccharide propionate agar medium (TOS) modified by addition of mupirocin (50 microg ml-1) and glacial acetic acid (1%, v/v), did not inhibit the growth of bifidobacteria compared with the control media yet inhibited the growth of Lactobacillus acidophilus, Lactobacillus gallinarum, Lactobacillus helveticus and Streptococcus gordonii. CONCLUSIONS: Addition of mupirocin (50 microg ml-1) and glacial acetic acid (1%, v/v) to TOS (TOS-AM50), is an effective selective medium for isolation and enumeration of Bifidobacterium spp. from chicken caeca samples. SIGNIFICANCE AND IMPACT OF THE STUDY: The development of an intestinal bifidobacteria-selective media contributes to the study of probiotics and prebiotics in poultry and potentially other species.     

Effect of Colostomy on the Circadian Rhythm in DNA Synthesis in the Rat Colon

Synthesis of DNA and mitosis in gut epithelium are not constant or random events but rather are characterized by circadian rhythmicity, which we reported persists even in fasted rats. Others suggest that rhythms persist because rats anticipate food, causing nerve impulses to propagate caudally in the gut at usual meal times, or that digestive products from previous feedings cause rhythms in the lower tract. We studied colonic DNA synthesis in rats that had been given colostomies. In one study, the distal colon was isolated neurally from proximal gut by means of an end colostomy. In a second study, rats were subjected to loop colostomy; some intrinsic innervation of the gut wall remained intact. Sprague-Dawley male rats, 8 weeks old, were acclimated to a 12:12 light-dark cycle. Colostomies were performed after a 48-h fast. The rats were fed ad libitum for 4 weeks after surgery. Operated rats and an equal number (n = 30) of control rats (unoper-ated) were divided into four subgroups that were killed at 07:00,13:00,19:00, and 01:00 h. Each rat was injected with tritiated thymidine 30 min before it was killed. Proximal and distal colon were analyzed for incorporation of radioactivity (DNA synthesis). Results are reported as counts per minute per microgram of DNA and were analyzed using analysis of variance and the t test. Significant daily variation was found in proximal colon, both from control and operated rats. Rhythms were still present in colon distal to loop colostomy but were lost in the distal stump in rats that received an end colostomy. The mammalian “biological clock” regulates most circadian rhythms by neurohumoral mechanisms; however, our results suggest that the intrinsic enteric nervous system is important in the propagation of a signal that causes rhythmic cell proliferation in the gut in the intact animal.     

Abundance and feeding of wintering and migrating aquatic birds in two sampling areas of Lake Balaton in 1983–1985

The investigation was carried out at two sampling areas in Lake Balaton (surface area 600 km²), of which one was hypertrophic and the other was mesotrophic. Species diversity was higher in the hypertrophic area, primarily due to a higher number of Anatid species. Contents of crops, gizzards, and intestines were analysed in 321 of the 361 birds collected. Diet was similar in certain species (Aythya fuligula, A. f. ferina, Anas querquedula) despite differences in the trophic state of their habitats. However, in other species (Anas p. platyrhyncha, Aythya nyroca, Bucephala c. clangula), percentage distribution of food items more or less reflected the food resources of the two areas in the digestive tracts. I concluded that the former species are highly selective in their feeding.     

Escherichia coli mutY-dependent mismatch repair involves DNA polymerase I and a short repair tract

Repair of heteroduplex DNA containing an A/G mismatch in a mutL background requires the Escherichia coli mutY gene function. The mutY-dependent in vitro repair of A/G mismatches is accompanied by repair DNA synthesis on the DNA strand bearing mispaired adenines. The size of the mufY-dependent repair tract was measured by the specific incorporation of -[³²P]dCTP into different restriction fragments of the repaired DNA. The repair tract is shorter than 12 nucleotides and longer than 5 nucleotides and is localized to the 3 side of the mismatched adenine. This repair synthesis is carried out by DNA polymerase I.