Assembly of the mitochondrial membrane system XIX

Summary Two F^- mutants deficient in conjugation with F-type donors are isolated and characterized. Phenotypically, these mutants are similar; they have heptose-less lipopolysaccharide and lack some outer membrane protein. Genotypically, they are different. One mutant harbours a point mutation in the 70 to 74 min region, while the other is deleted for the chromosomal region 6.5 to 8.5 min. Comparison of the properties of the conjugation-deficient mutants described in this paper with other such mutants suggests than an outer membrane protein is the receptor for the F-pilus.     

Characteristics of acquired resistance of lambs to mature ticks Hyalomma asiaticum asiaticum (experimental studies)]

A new method was employed for studies of parasite-host relationships between ixodid ticks and their hosts. It has been established that ixodid ticks are able to desensibilize the reactive sensibility of the host and to satiate themselves without unhibiting the latter. Every day and long parasitism of the ticks on cattle (in nature) and increasing doses of secretion of the ticks' saliva (sensibilizer) lead apparently to the weakening of the host's organism (desensitization). However, under laboratory conditions in hosts a resistence to bites of ixodid ticks can appear.     

Incorporation of H3-thymidine into the oocytes of a sterlet in the early meiotic prophase]

DNA synthesis in meiotic oocytes of the sterlet (A. ruthenus) has been studied during early prophase stages using H3-thymidine. The pattern of H3-thymidine incorporation is similar to that in oocytes of Amphibia and Osteichthyes. In the oogonia as well as in the leptotene and zygotene oocytes, the label is predominantly localized over chromosomes. An intensive incorporation of H3-thymidine into the material of the heterochromatic "cap" has been observed during pachytene. Thus, the main synthesis of extra DNA in the sterlet oocytes occurs during pachytene. No DNA in synthesized by the diplotene oocytes.     

Effect of fasting and insulin on the glucagon-induced orthophosphate incorporation to the isolated perfused rat liver.

Isolated perfused fed rat livers spontaneously liberated glucose and orthophosphate to the medium; 24-hr fasted rat livers did not exhibit these phenomena. In perfused fed rat livers, glucagon (2 mug) increased glucose output and promoted orthophosphate incorporation. In perfused fed rat livers, insulin (250 or 500 mU) inhibited the spontaneous liberation of glucose and orthophosphate. Comparable doses of insulin significantly reduced the glucagon (2 mug)-induced increase in glucose output from perfused fed rat liver, but did not affect orthophosphate uptake by the organ.     

Ferritin intestinal absorption.

Ferritin as a source of iron was consiered. A good iron absorption rate appears in normal rats with an in vivo absorption technique. The same absorption appears in iron-deficient animals. The iron stored in intestinal wall is lower in anemic rats than in normal ones, suggesting a higher draw of iron from lumen to blood.     

The ultrastructure of the intraerythrocytic stages of Babesia herpailuri-trophozoites and merozoites after treatment with imidocarb (3,3'-bis-2-imidazolin-2-yl)-carbanilide (author's transl)]

The fine structure of trophozoites and especially of merozoites of Babesia herpailuri is described before and after treatment with Imidocarb (Wellcome). The mostly piriform to oval merozoites possess an outer membrane and a supporting membrane below. The intratorium consists of a polar ring, rhoptries micronemes and the sperical body which lies beside the big nucleus and next to mitochondria. The endoplasmic reticulum and invaginations are not clearly formed. The cellular changes of Babesia herpailuri, observed one hour after drug treatment in trophozoites and six hours later in merozoites, concern the form and function of the parasite: widening of the subpellicular endoplasmic reticulum and of the perinuclear space; sporadic dilatation of the endoplasmic reticulum of the merozoites (9 fig.). Damaged membranes, dissolution of the cellular membrane, disintegration of the nuclei as are known effects of the Berenil treatment to Babesia herpailuri, are not noted results after the Imidocarb treatment. The original membrane systems of trophozoites as well as of merozoites, remain unaffected by the drug as long as investigations were carried on (24 h). The satisfying prophylactic effect of Imidocarb as well as the insignificant cellular damages on merozoites may be due to the small feeding of hemoglobin.     

Adenosine triphosphate hydrolysis in rat dental tissues. A histochemical study to differentiate the enzymes involved.

The purpose of this study was to try to differentiate histochemically between the various enzymes which may catalyze the hydrolysis of ATP in developing rat dental tissues. Freeze cut and freeze dried sections of molar and incisor teeth were incubated in lead capture-based media at pH 5.0, 7.2 or 9.4 with one of the following substrates: beta-glycerophosphate, AMP, ADP, ATP, AMP-PNP and tetrasodium pyrophosphate. To establish the enzymatic nature of the hydrolysis parallel sections were incubated after prior fixation in either formaldehyde or glutaraldehyde. By comparing the enzymatic stainings obtained with the various substrates and at the different pH:s, it was concluded that ATP can be visibly hydrolyzed in rat dental tissues by alkaline phosphatase (stratum intermedium, apical part of maturation ameloblasts, basal part of all ameloblasts, odontoblasts and subodontoblastic layer), specific ATPase (apical and basal parts of secretory ameloblasts) and ATP pyrophosphatase and/or adenylate cyclase (stratum intermedium, odontoblasts). Acid phosphatase, specific ADPase, 5'-nucleotidase, inorganic pyrophosphatase, 3':5'-cyclic-AMP-phosphodiesterase and adenylate kinase on the other hand, seem not to be engaged in the ATP hydrolysis to such a degree as to complicate the interpretation of the histochemical staining. The alkaline phosphatase part of the ATP hydrolysis appeared to be rather insensitive to aldehyde fixation, while the hydrolysis effected by specific ATPase and ATP pyrophosphatase and/or adenylate cyclase was extinguished after fixation with formaldehyde for 4 h or glutaraldehyde for 10 min.     

Incorporation of tritiated amino acids into the ultrastructure of the cerebral cortex following phenamine stimulation]

The method of electronoscopic autoradiography has revealed an increased biosynthesis of protein by neuronal and glial cells of the motor cortex of rats under phenamine stimulation. The increased level of incorporation of labelled precursors in the molecular layer of the cortex is likely to be associated with increased accumulation of newly synthetized protein in axo-dendritic synapses due to stimulation of the rapid component of the axonal transport of macromolecules. At the same time, participation of the autonomic protein-synthetizing system in the biosynthesis of synaptic proteins is not excluded. The labelled products were found to localize in the field of the thorn apparatus in processes of the "structural-functional" adaptation of synaptic entrances (A. A. Manina, 1972).