The oxygen consumption of 6 ciliated protozoa species in conditions of different oxygen concentration was studied using the electrode polarograph. Two types of dependence have been suggested to describe the ciliate oxygen consumption rates (OCR) under different oxygen concentrations. A high level of ciliate respiratory metabolism was established, both large and small ciliates reacting moreover under the oxygen changes similarly. Coefficients for correcting respiration at the lower oxygen concentrations were developed.
The catfish Pangasius hypophthalmus from South-Eastern Asia uses the airbladder as an accessory respiratory organ. The airbladder is situated at the dorsal part of the body cavity and is connected with the esophagus by a short pneumatic duct lined with mucus cells. The histological and ultrastructural study reveals that the wall of the airbladder is composed of three layers: the outer layer of serosa membrane, the middle one of connective tissue with many collagen fibres, and the inner layer - the simple respiratory epithelium. The medium and inner layers form numerous septa protruding into the lumen of the airbladder. The central septum divides the airbladder longitudinally into two chambers. The respiratory epithelium consists of a single type of flat cells covering a dense capillary network. Ciliated and mucus cells are absent. Epithelial cells possess long and thin microvilli on their surface. Their cytoplasm contains a large nucleus, the Golgi apparatus, rough endoplasmic reticulum, mitochondria, and a few electron-dense and lamellar bodies accumulating surfactant. The air-blood barrier is composed of epithelium, connective tissue, and endothelium with a thickness ranging from 0.2 to 2.4 mum.
From 1984-1991 in the Stavropol territory of Russia the strategy of seasonal development was studied in the rageeed leaf beetle Zygogramma suturalis F.During the laboratory and field studies a great diversity of the female adult diapause was revealed.It differs in the time of appearance, its duration and biological significance.The incidence of diapause varies considerably in different years.Sometimes it ensures the formation of an overwintering population, and other times it changes the duration reproduction and affects the abundance of the next generation.Respiraton intensity is a significant index of the physiological state of beetles.The oxygen consumption in diapausing females is 2-5 times lower than in active reproducing ones; in young 2-6 days old beetles the highest respiration level is observed.Relatively short spring and summer diapause is characterized by the same low metabolism rate as the very long summer-winter or autumnal-winter one.The males have a higher respiration rate than females, but seasonal pattern of the male respiration resembles the female one.
We investigated the hypothesis that the motor trigeminal nucleus, consisting of expiratory motoneurons, might be influential in termination of inspiration. We addressed the issue by comparing the effects on neural respiration of a reversible, unilateral, pharmacologic blockade of the motor trigeminal nucleus (5M), the medial parabrachial nucleus (PB), and of other nearby structures that are neutral for respiration in anesthetized, vagotomized, paralyzed, and ventilated cats. The blockade was achieved by microinjections of 2% xylocaine, laced with Pontamine Sky Blue to identify sites of injections, from the tip of a penetrating microelectrode. Integrated phrenic neurograms were recorded to quantify the time of neural inspiration (T I), expiration (T E), and the peak phrenic amplitude. We found that blockade of the 5M caused a pattern of apneustic respiration, consisting of a selective prolongation of inspiratory phases that were interrupted by short expiratory pauses. In contrast, blockade of the PB resulted in a prolongation of both T I and T E, which corresponds to a mere slowing of respiration. The results confirmed important functions of the rostral pons in ventilatory control but pointed to the 5M rather than PB as a structure underlying the inspiratory off switch. We conclude that the motor trigeminal nucleus may have a part in the pontine pneumotaxic mechanism.
In waters of Dobczyce reservoir, the organic carbon content, biomass of algae and bacteria, respiration of bacteria and respiration of aquatic organisms (measured by oxygen uptake), and energetic expenditures per unit of bacterial biomass ('costs of maintenance') at the beginning of spring water bloom (May, 1996) caused by Nitzschia palea (Kutz.) W. Sm. were greater than those in the second phase of bloom. However, photosynthesis of algae was greater in the second one. In the surface layer of bottom sediments, the greatest values of measured parameters were noted in the second phase of water bloom but the 'costs of maintenance' of bacteria reached maximum values one week after of water bloom break.
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