Changes in Microbial Communities Associated with the Sea Anemone Anemonia viridis in a Natural pH Gradient

Ocean acidification, resulting from rising atmospheric carbon dioxide concentrations, is a pervasive stressor that can affect many marine organisms and their symbionts. Studies which examine the host physiology and microbial communities have shown a variety of responses to the ocean acidification process. Recently, several studies were conducted based on field experiments, which take place in natural CO₂ vents, exposing the host to natural environmental conditions of varying pH. This study examines the sea anemone Anemonia viridis which is found naturally along the pH gradient in Ischia, Italy, with an aim to characterize whether exposure to pH impacts the holobiont. The physiological parameters of A. viridis (Symbiodinium density, protein, and chlorophyll a+c concentration) and its microbial community were monitored. Although reduction in pH was seen to have had an impact on composition and diversity of associated microbial communities, no significant changes were observed in A. viridis physiology, and no microbial stress indicators (i.e., pathogens, antibacterial activity, etc.) were detected. In light of these results, it appears that elevated CO₂ does not have a negative influence on A. viridis that live naturally in the site. This suggests that natural long-term exposure and dynamic diverse microbial communities may contribute to the acclimation process of the host in a changing pH environment.     

Proliferative activity of endotheliocytes of growing corneal capillaries in the rabbit

The intensity of capillaries growth in the rabbit's cornea was investigated after chemical burn and exposure to colchicine. Proliferative activity was determined in endothelial cells along the course of newly formed capillaries. Growth intensity proved to be 2 times higher when burn and colchicine effects were combined, than in case of burn alone. The increase in the proliferative activity of endothelial cells and the peculiarities of their arrangement were found in both cases. The most active proliferation was observed in cells located in a zone where capillaries originated from intact vessels of the limb. The process of new vessel formation depends on endotheliocyte shift from this zone towards the site where growth-stimulating factors were applied.     

The functional-morphological state of the myocardium in experimental massive embolism of the pulmonary artery]

A comparative study of hemodynamic and structural-metabolic changes in the myocardium of the right (RV) and left ventricles (LV) in acute massive pulmonary artery embolism was made in 19 mongrel dogs. In the control group the activity of SDH, MDH, GDH, NADH-DH in LV were higher than in RV. The numeral density and relative area of mitochondrial profile surface in LV was higher that in RV. A significant increase in afterload on RV causes intensification of cell respiration, a rise in numeral density and relative area of mitochondrial profile surface. Weakening of LV work leads to contrary structural-metabolic changes. Thus, contrary changes in hemodynamic loads on RV and LV in acute compensative massive pulmonary artery embolism correlated with contrary changes in their cell metabolism.     

Status of the capillary endothelium of the lung in normovolemic perfusion of the organ through the system of the pulmonary artery

Pulmonary perfusion for 30 min to the dog under conditions of normovolemia is not accompanied with any essential changes in parameters of alveolar capillaries endothelium. Just the opposite, transformation of endothelial lining of the peribronchial capillaries demonstrates possible disturbances of the liquor transport across the walls of these vessels. The volumetric part of the interstitial space near these capillaries increases, while in the alveolar septa it does not change. In lymph formation, flowing out of the lung, together with bronchial capillaries, blood capillaries of the alveoli must take part.     

The effect of isoprenaline on the aggregation and adhesive properties of circulating rat neutrophils]

It is well known that isoprenaline (1-3-4-dihydroxy-phenyl-isopropyl-aminoethanol) (IP) induce necrosis in myocardium of laboratory animals, which is similar to pathomorphological development of clinical myocardial infarction. This process is accompanied by peripheral blood leukocytes. The IP-inductor effects on arachidonate-dependent aggregation and endothelial adhesion of peripheral blood neutrophils (PN) were studied in this paper. The enhancement of PN aggregational properties within 2-4 hours after intravenous IP-injection to rats was demonstrated. Using the method of vital microscopy it was shown that intravenous IP-injection to rats or IP-application on rat mesentery lead to an increase of leukocyte's marginal pool on the endothelium of mesenteric venules. However, it was noted that the change of cell functional properties is not due to the direct influence of IP on PN. The pathogenetic mechanisms of IP-induced cardiomyopathy in rats were discussed.     

Studies on the mucilaginous layer of barley (Hordeum vulgare) roots

The nature and composition of the external, mucilageneous layer of barley roots was studied by extraction methods and electron microscopy. Barley roots were extracted with chloramphenicol-supplemented water at 35°C, with NH₄Cl at various concentrations and with pectinase solutions. The kinetics of transfer of bacteria, total and reducing sugars, proteins, Ca⁺⁺ and K⁺ was studied, and the removal of the mucigel from the extracted roots was followed under the electron microscope. Within 2 to 3 hours of treatment with water, the rate of release of sugars, ions, proteinaceous material and bacteria, was reduced to almost zero. Increasing concentrations of ammonium chloride enhanced transfer of ions to the extracting solution but affected sugar extraction to a lesser extent. Electron micrographs of ammonium chloride-extracted roots revealed that the amorphous, rather than the fibrillar fraction of the mucigel was removed. At 10³ meq of NH₄Cl, distortion of the epidermal layer of the extracted roots was observed. With pectinase as an extractant, there was some enhancement of sugars and ions transfer from the roots to the extracting solution. Electron micrographs showed that the main site of extraction of pectinase was the boundary layer between the root surface and the mucigel. Paper chromatography of the acid hydrolyzate of the water extracted, ethanol-precipitated fraction showed the presence of compounds identical in Rf values to D-glucose, D-arabinose, D-glucuronic acid and D-galacturonic acid. Present methods available for the extraction of the mucigel do not allow the differentiation between extracted pectic compounds which originate from the internal root tissue, and the mucigel. re]19751128 Dept. of Field Crops Dept. of Soil and Water Sciences Dept. of Microbiology and Phytopathology     

Distribution of proteins in neural membranes as a factor of reabsorption of endoneural (interstitial) fluid

An investigation on distribution of horseradish peroxidase (HP) product in the sciatic nerve membranes of albino rats, after HP intravenous injection, has been performed. Getting into the interstitial space of epineurium across the microvessel walls, HP spreads as far as the internal layer of the perineural membrane, forming a distinct gradient of concentration of protein at its border. In 60 min after injection of the tracer the value of the perineural-endoneural gradient for proteins is about 70-80% of the value of the plasma-endoneural gradient. A possible mechanism of the endoneural fluid evacuation, connected with various values of protein concentration in the endoneural space and within the nerve perineural membrane is discussed.