The cellular differentiation of M cells from crypt undifferentiated epithelial cells into microvillous epithelial cells in follicle-associated epithelia of chicken cecal tonsils

To clarify the cellular origin and the fate of M cells, detailed distributions of the epithelial cells were investigated scanning electron microscopically on the follicle-associated epithelia (FAE) of chicken cecal tonsils. The distribution of M cells was closely related with the situation of the crypt orifices in chicken cecal tonsils. In undeveloped cecal tonsils, the intestinal crypts were localized at the periphery of the FAE. In these tonsils, M cells without microvilli (M(0)) were predominantly populated in the basal region of the FAE, whereas goblet cells and microvillous epithelial cells (MV) were more distributed in the middle to the apical region of the FAE. A few M cells with short microvilli were dispersed throughout the FAE. Significantly shrunk MV (MVs) clustered together in transitional portions from the lateral face to the roof of the FAE. In well-developed cecal tonsils, the crypts also opened at the lateral surface in addition to the periphery of the FAE. In these tonsils, the M(0) accumulated densely in the small areas around the crypt orifices exclusively. No sign of exfoliation of apoptotic epithelial cells was found in the M(0)-accumulated areas and at their peripheral boundaries. The MVs were often clustered in the central regions among the crypt orifices in addition to the roof of the FAE. These findings suggest that M cells are directly derived from the undifferentiated crypt epithelial cells, not fall into apoptotic cell death and further differentiate into MV in the FAE of chicken cecal tonsils.     

Anesthesia,fasting tolerance,and nutrient requirement of juvenile northern bluefin tuna

ABSTRACT:   The present study aimed to investigate a suitable anesthesia protocol for nutritional studies, fasting tolerance, and nutrient requirements for maintenance in juvenile northern bluefin tuna Thunnus orientalis weighing 0.8–0.9 g. The fish grew in a mass seedling production under completely controlled aquaculture. The solution of 0.2 mL 2-phenoxyethanol/L prepared by filtered seawater has been notably estimated as a anesthesia protocol for the juvenile, due to a shorter mean time necessary for anesthesia and recovery and higher survival rate at 24 h after recovery. All other anesthetics, 0.1 and 0.3 mL 2-phenoxyethanol/L, 0.05, 0.1 and 0.2 mL 4-allyl-2-methoxyphenol/L, and cool water temperature shocks at 16.8, 12.6 and 10.4°C, were inferior. In a 5-day tolerance test, the juvenile was fed sand lance Ammodytes personatus through the rearing period or fasted for 2, 3, 4 and 5 consecutive days. Survival rates were about 80 or 60, 50, 10 and 0%, respectively. From the relationships between days fasting and energetic and nutritional retentions, juvenile tuna require about 142.7 kJ, 5.46 g protein and 0.44 g fat/kg body weight a day for maintenance, indicating remarkably higher requirements than other aquaculture fish.     

Response of enzyme activities and metabolic intermediate concentrations to epinephrine administration in hepatopancreas and muscle of carp

SUMMARY: Common carp Cyprinus carpio were administered intraperitoneally with 10 μmol epinephrine per 100 g bodyweight, and enzyme activities and metabolic intermediate concentrations were determined in the hepatopancreas and muscle. Glycogen phosphorylase a (GPase a) activity together with cyclic AMP (cAMP) concentration was increased, and glycogen content was decreased in the hepatopancreas and muscle at 2 h after the administration. The epinephrine administration also increased hepatopancreatic glucose-6-phosphatase and fructose-1,6-biphosphatase activities as well as serum glucose, lactate, and free amino acid concentrations. Furthermore, its administration increased phosphofructokinase activity together with lactate, fructose-6-phosphate, adenosine-5'-monophosphate, and adenosine-5'-diphosphate concentrations and decreased citrate concentration in the muscle. Thereafter, almost all parameter concentrations in the hepatopancreas and muscle recovered to the pre-administered levels during 24 h after the administration. These results suggest that epinephrine administration enhanced glycogenolysis and gluconeogenesis in the hepatopancreas, and released glucose into the bloodstream to supply it to the muscle. The blood glucose together with muscle glycogen seems to be metabolized through enhanced glycolysis in the muscle.     

In situ hybridization for the demonstration of bovine leukemia virus transcripts in lymphosarcoma cells using biotinylated probes.

Bovine leukemia virus (BLV) RNA was demonstrated in peripheral blood lymphocytes treated with concanavalin A or phytohemagglutinin from a BLV-infected ox, and in lymphosarcoma cells cultured without mitogen from an enzootic bovine leukosis cow by in situ hybridization using biotinylated DNA probes.     

Factors associated with antimicrobial-resistant Escherichia coli in zoo animals

Factors associated with the carriage of antimicrobial-resistant Escherichia coli isolates were analysed among zoo animals. An association was observed between selection of amoxicillin as the first-line therapy and a significantly higher percentage of resistance to ampicillin (54.5%) from 11 animals treated with antimicrobials, compared with isolates from 32 untreated animals (9.4%). In addition, the percentage resistance to kanamycin (36.4%), gentamicin (27.3%), trimethoprim (27.3%) and tetracycline (63.6%) from 11 treated animals was significantly higher than those from 32 untreated animals (3.1%, 3.1%, 3.1% and 25%, respectively), although these antimicrobials were rarely used. All kanamycin-, gentamicin- and trimethoprim-resistant isolates and more than half of the tetracycline-resistant isolates from treated animals were also resistant to ampicillin. Co-resistance to other antimicrobials with ampicillin was suggested to contribute to an increasing of resistance towards antimicrobials that were rarely administered. The present investigation revealed an association of antimicrobial treatment with the spread of antimicrobial-resistant bacteria among zoo animals.     

In Situ Detection of Antibiotic Amphotericin B Produced in Streptomyces nodosus Using Raman Microspectroscopy

The study of spatial distribution of secondary metabolites within microbial cells facilitates the screening of candidate strains from marine environments for functional metabolites and allows for the subsequent assessment of the production of metabolites, such as antibiotics. This paper demonstrates the first application of Raman microspectroscopy for in situ detection of the antifungal antibiotic amphotericin B (AmB) produced by actinomycetes—Streptomyces nodosus. Raman spectra measured from hyphae of S. nodosus show the specific Raman bands, caused by resonance enhancement, corresponding to the polyene chain of AmB. In addition, Raman microspectroscopy enabled us to monitor the time-dependent change of AmB production corresponding to the growth of mycelia. The Raman images of S. nodosus reveal the heterogeneous distribution of AmB within the mycelia and individual hyphae. Moreover, the molecular association state of AmB in the mycelia was directly identified by observed Raman spectral shifts. These findings suggest that Raman microspectroscopy could be used for in situ monitoring of antibiotic production directly in marine microorganisms with a method that is non-destructive and does not require labeling.     

Oxidative stability of salmon and herring roe lipids and their dietary effect on plasma cholesterol levels of rats

ABSTRACT:   The oxidative stability of lipids from salmon roe and herring roe was compared with those of commercial fish oils originated from sardine and tuna. Both fish roe lipids contained high amounts of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Total EPA and DHA was more than 35% of total fatty acids in both roe lipids. On the basis of oxygen consumption, fish roe lipids showed the higher oxidative stability than both fish oils. This tendency in oxidative stabilities was also confirmed by the determination of propanal formation during oxidation. Analyses of lipid compositions suggested that the higher oxidative stabilities of fish roe lipids would be mainly due to the presence of phospholipids in them. Dietary effects of salmon and herring roe lipids were also determined. Little increase in total cholesterol level was observed in plasma lipids in rats fed salmon and herring roe lipids, although cholesterol content in fish roe lipids were 6.3% and 9.7% of total lipids for salmon roe and herring roe.     

Response of enzyme activities and metabolic intermediate concentrations to a long burst of exercise and following resting in muscle and the hepatopancreas of carp

ABSTRACT: The responses of enzyme activities and metabolic intermediate concentrations to a long burst of exercise and following resting were examined in muscle and the hepatopancreas of carp Cyprinus carpio . A 15 min burst of exercise made the fish so exhausted that they could not swim any more. In muscle, the exercise decreased glycogen content significantly and increased lactate content significantly, resulting in a lowered pH. Furthermore, the burst of exercise decreased phosphofructokinase (PFK) activity significantly, although it changed adenosine-5'-monophosphate, adenosine-5'-diphosphate, adenosine-5'-triphosphate, fructose-6-phosphate and citrate concentrations within ranges that could activate PFK. In the hepatopancreas, the exercise increased glucose-6-phosphatase and fructose-1,6-bis-phosphatase activities, and glucose and lactate concentrations in the serum, and it decreased glycogen content. Even at 3 h resting after the burst of exercise, the fish had not completely restored many parameters. These results suggest that although the fish tried to enhance in vivo muscular glycolysis through the activation of PFK by changes in metabolic intermediate concentrations, glycolysis seemed to decrease markedly through the inhibition of PFK as a result of the lowered pH. However, the hepatopancreas made a contribution to muscular exercise through glucose supplementation by enhanced gluconeogenesis and glycogenolysis, indicating the presence of an interdependence of carbohydrate metabolism between muscle and the hepatopancreas in the fish.     

Application of a compact magnetic resonance imaging system for toxicologic pathology: evaluation of lithium-pilocarpine-induced rat brain lesions

Magnetic resonance imaging (MRI) is a useful noninvasive tool used to detect lesions in clinical and veterinary medicine. The present study evaluated the suitability of a new easy-to-use compact MRI platform (M2 permanent magnet system, Aspect Imaging, Shoham, Israel) for assisting with preclinical toxicologic pathology examination of lesions in the rat brain. In order to induce brain lesions, male Sprague-Dawley rats were treated once with lithium chloride (127 mg/kg, intraperitoneal [i.p.]) followed by pilocarpine (30 mg/kg, i.p.). One week after dosing, the perfused, fixed brains were collected, analyzed by the MRI system and examined histopathologically. MRI of the brain of treated rats revealed areas of high T1 and middle to low T2 signals, when compared with the controls, in the piriform cortex, lateral thalamic nucleus, posterior paraventricular thalamic nucleus and posterior hypothalamic nucleus of the cerebrum. The altered MRI signal areas were consistent with well-circumscribed foci of neuronal cell degeneration/necrosis accompanied by glial cell proliferation. The present data demonstrated that quick analysis of fixed organs by the MRI system can detect the presence and location of toxicologic lesions and provide useful temporal information for selection of appropriate sections for histopathologic examination before routine slide preparation, especially in complex and functionally heterogeneous organs such as the brain.     

Selection of ABC genes for candidate genes of morphological changes in hydrangea floral organs induced by phytoplasma infection

The mechanism underlying the green colouration of floral organs in phytoplasma-infected hydrangeas was studied. Elucidation of morphological changes of floral organs induced by phytoplasma infection and a comparison of the expression level of genes related to floral organ morphogenesis between phytoplasma-infected and non-infected hydrangea plants was conducted. Sixteen hydrangea (Hydrangea spp.) cultivars were used to study structural changes in floral organs induced by Japanese Hydrangea Phyllody (JHP) phytoplasma infection. The homeotic conversion of sepals to leaves was observed in different number of florets between cultivars, and was observed in 75.8–100% of the decorative florets and 2.7–67.3% of the non-decorative florets of JHP phytoplasma-infected inflorescences. The homeotic conversion of carpels to leaves was observed in 1.2–17.9% of the decorative florets and 0.1–18.9% of the non-decorative florets of infected inflorescences. The expression levels of hydrangea orthologues of class A, B and C genes were suppressed in the infected inflorescences during the developmental stage in which no morphological differences in the internal structure of floral organs have been observed. The contribution of this suppression to homeotic conversion of sepals and carpels to leaves was suggested.