Dependence of properties of polyclonal antibodies to (2'-5')-oligoadenylates on the method of hapten binding to an immunogen

To elucidate the antibody-(2'-5')oligoadenylate relation to the mode of the hapten-immunogen conjugation, a new (2'-5')oligoadenylic acid trimer derivative containing a 2'-terminal N6-(5-carboxypentyl)adenosine and its 125I-labeled immunogenic conjugate were synthesized. The immunization with this conjugate and with a conjugate based on the 2',3'-O-[1-(2-carboxyethyl)]ethylidene derivative of the (2'-5')triadenylic acid gave antisera with different affinities toward modified (2'-5')oligonucleotides. Epitopes involved in the (2'-5')oligomer-binding to different antisera were found.     

Development of Biosensors for Phenol Determination from Bacteria Found in Petroleum Fields of West Siberia

Nine gram-negative bacterial strains, selected from 300 strains isolated from soils of the West Siberian petroliferous basin and growing on oil and oil products, consume phenol as a single carbon and energy source. The strains were used for the development of a sensor bioreceptor. The most active 32-I strain was shown to bear a plasmid responsible for phenol degradation. The plasmid-free derivative of this strain, 32-I-1, did not grow on phenol. The possibility of creating a model biosensor for phenol based on the plasmid-containing 32-I strain is considered. The detection limit for phenol was 5 M. The optimum conditions for the sensor operation are: pH 7.4, 35°C, and operation time 30 h.     

Involvement of accessory neurosecretory nuclei of hypothalamus in the formation of hypothalamohypophyseal system during prenatal and postnatal development in rats

We studied the development of direct axonal connections of the accessory neurosecretory hypothalamic nuclei with the posterior pituitary lobe on the fixed rat brain from day 15 of embryogenesis until day 10 of postnatal development using the retrograde diffusion method of the lipophilic fluorescent carbocyanine dye 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate along the neuronal membranes. The marker was applied onto the posterior pituitary lobe and, after incubation in a fixative, fluorescing bodies of nerve cells were visualized in the hypothalamus. Neuronal axons of the retrochiasmatic nucleus were the first of the accessory nuclei to ingrow in the posterior pituitary lobe (on days 16-17 of embryogenesis). Neurons of the circular and dorsolateral nuclei and the nuclei of the median bundle of the forebrain sent their axons to the posterior pituitary lobe starting from the first days of postnatal development. No direct connections of the anterior commissure and perifornical accessory nuclei with the posterior pituitary lobe were found in perinatal development. These facts are discussed in the light of concepts about the different functional role of accessory peptidergic hypothalamic nuclei in rats.     

Effect of corticoliberin fragment CRF4-6 on blood glucose level and body temperature of rats

The effects of tripeptide corticoliberin fragment CRF4-6 (Pro-Pro-Ile) on blood glucose level and the rat body temperatire were investigated. Intracerebroventricularly injected CRF4-6 (6, 30, 150 nmol/head) causes a dosedependent hyperglycemia and hyperthermia in anaesthetized animals. Corticotropin releasing factor antagonist alpha-helical CRF4-6 (6.5 nmol/head) abolishes the influence of tripeptide CRF4-6 (6 nmol/head) on blood glucose level and body temperature of rats. Bilateral adrenalectomy has no effect on tripeptide-induced hyperglycemia and hyperthemia. This result indicates that hyperglycemic and hyperthermal effects of tripeptide occur independently of adrenal gland catecholamines. In addition, non-pituitary corticoliberin receptors are involved in CRF4-6 influences on blood glucose level and body temperature.     

Physiological and morphological characteristics of the rhythmic contractions of the amnion in veiled chameleon (Chamaeleo calyptratus) embryogenesis

A morpho-functional study of the veiled chameleon (Chamaeleo calyptratus) amnion was performed as part of a general comparative study of amnion rhythmic contractions (ARC) in reptile and bird embryogenesis. Eggs incubated at 27.5 degrees C were used at different developmental stages from day 80 (D80) to D184 for the recording of ARC using a force transducer. Slow ARC, about 1 min in duration, were revealed from D88 (stage 31) to the near-hatching stages (incubation time was 183-198 days). The frequency and amplitude of slow ARC increased significantly towards the end of incubation. This ARC enhancement correlated with the differentiation of smooth muscle elements in the amniotic membrane from single spindle-shaped cells to complex "star-like" structures and with the development of the actin fibers, revealed by phalloidin, in the amniotic muscle layer. Short-term changes in temperature influenced ARC and heart rate (HR). Cooling to 25 degrees C from the control (27.5 degrees C) resulted in a significant decrease in both ARC frequency and HR. Heating to 30 degrees C significantly increased the embryonic HR, but not ARC frequency. Within the temperature range from 25 to 30 degrees C the temperature effect on ARC frequency and HR was reversible.     

Isoform diversity of giant proteins in relation to passive and active contractile properties of rabbit skeletal muscles

The active and passive contractile performance of skeletal muscle fibers largely depends on the myosin heavy chain (MHC) isoform and the stiffness of the titin spring, respectively. Open questions concern the relationship between titin-based stiffness and active contractile parameters, and titin's importance for total passive muscle stiffness. Here, a large set of adult rabbit muscles (n = 37) was studied for titin size diversity, passive mechanical properties, and possible correlations with the fiber/MHC composition. Titin isoform analyses showed sizes between approximately 3300 and 3700 kD; 31 muscles contained a single isoform, six muscles coexpressed two isoforms, including the psoas, where individual fibers expressed similar isoform ratios of 30:70 (3.4:3.3 MD). Gel electrophoresis and Western blotting of two other giant muscle proteins, nebulin and obscurin, demonstrated muscle type-dependent size differences of < or =70 kD. Single fiber and single myofibril mechanics performed on a subset of muscles showed inverse relationships between titin size and titin-borne tension. Force measurements on muscle strips suggested that titin-based stiffness is not correlated with total passive stiffness, which is largely determined also by extramyofibrillar structures, particularly collagen. Some muscles have low titin-based stiffness but high total passive stiffness, whereas the opposite is true for other muscles. Plots of titin size versus percentage of fiber type or MHC isoform (I-IIB-IIA-IID) determined by myofibrillar ATPase staining and gel electrophoresis revealed modest correlations with the type I fiber and MHC-I proportions. No relationships were found with the proportions of the different type II fiber/MHC-II subtypes. Titin-based stiffness decreased with the slow fiber/MHC percentage, whereas neither extramyofibrillar nor total passive stiffness depended on the fiber/MHC composition. In conclusion, a low correlation exists between the active and passive mechanical properties of skeletal muscle fibers. Slow muscles usually express long titin(s), predominantly fast muscles can express either short or long titin(s), giving rise to low titin-based stiffness in slow muscles and highly variable stiffness in fast muscles. Titin contributes substantially to total passive stiffness, but this contribution varies greatly among muscles.     

Impairment of energy metabolism in rabbit tissues during ammonia toxicosis

The studies are conducted on the model of grave toxicosis in vivo in rabbits. It is shown that an increase in the ammonia content in blood and tissues enhances the content of lactate, glutamate, oxaloacetate in the liver and kidneys of animals, decreases the level of pyruvate, alpha-ketoglutarate and malate in the liver tissue. The NAD+/NADH ratio in the cytoplasm of the liver and kidney cells decreases, the ratio of NADP-pairs in the cytoplasm and mitochondria of these tissues noticeably increases. The energy metabolism is disturbed sharply, the content of adenosine phosphates lowers.     

Effect of astasilid on the stimulation of peritoneal macrophages

The effect of astasilid, a sucrose monoester and the effect of mainly unsaturated fatty acids from the lipid fraction of Astasia longa on immunocompetent cells--macrophages of the mouse peritoneal cavity were studied. It was shown that astasilid increased 7.5-8.5-fold expression of Fc-receptors on the macrophage plasmic membranes and stimulated 5.5-6.5-fold the macrophage capacity for Fc-dependent phagocytosis of sheep red blood cells. Astasilid had no effect on migration of the macrophages into the abdominal cavity.