FISH analysis of the telomere sequences of bulldog ants (Myrmecia: Formicidae)

Chromosomes from several species of ants from the genus Myrmecia were hybridized with deoxyoligomer probes of either (T₂AG₂)₇, the putative insect telomere repeat sequence, or (T₂AG₃)₇, the vertebrate telomere repeat sequence. While both sequence hibridized over a range of stringency conditions, (T₂AG₂)_n was clearly the predominant sequence at the termini of the Myrmecia chromosomes. No interstitial sites of either sequence were detected. The genus Myrmecia has a wide range of karyotypes, with chromosome numbers ranging from 2n=2–84. It has been hypothesized that the ancestral karyotype was 2n=4 and karyotype evolution proceeded with an increase in chromosome number. In the absence of detectable interstitial sites of telomere sequence, it is interesting to speculate on the origin of the new telomeres as the chromosome numbers increased.     

Carcinogenesis in accessory sex organs of rats induced by 3,2′-dimethyl-4-aminobiphenyl: response to androgen deprivation

 It is generally accepted that early human prostate cancers reveal higher androgen dependency than do advanced ones. In the present study, we examined whether the animal model of prostate cancer has already lost androgen dependency at the early stages of carcinogenesis. At experimental week 46, androgen deprivation was induced in rats and the incidences of atypical hyperplasia and cancer were examined in the ventral, dorsolateral prostate, coagulating glands, and seminal vesicles. Androgen deprivation significantly lowered the incidence of atypical hyperplasia in all four organs. As for the incidence of cancer, no significant differences were observed in the coagulating glands and seminal vesicles. Regarding atypical hyperplasia, androgen deprivation significantly decreased the proliferative cell nuclear antigen labeling index in the coagulating gland and seminal vesicles. The presence of cancer was also decreased in the coagulating gland but not in the seminal vesicles. With control group specimens, more intense staining of androgen receptor was observed in atypical hyperplasias than in cancers. Compared with the atypical hyperplasias, the cancers revealed low androgen dependency at the early stages of carcinogenesis. The cancers in the seminal vesicles also revealed higher androgen independency than did those in the coagulating gland. Accepted: 6 May 1997     

Unique tissue distribution of a mouse macrophage C-type lectin

We examined mouse tissue for the expression of macrophage galactose/N-acetylgalactosamine-specificC-type lectin using a rat monoclonal antibody (mAb) specificfor this lectin (mAb LOM-14). The binding of mAb LOM-14 wasdetected in detergent extracts from tissue by means of immunoblottinganalysis. It was shown that this mAb did not cross-react withmouse hepatic lectins, a structural homologue. The macrophagelectin was widely distributed among various mouse tissues asjudged by the affinity isolation followed by the immunochemicaldetection. The exceptions were brain, liver, kidney, small intestine,and peripheral blood. Extracts from these organs exhibited,at best, very weak signals upon mAb LOM-14 binding, despitethe presence of cells expressing macrophage markers. The mostintense signal was observed in the extract from skin, suggestingthat cells expressing this lectin are abundant in skin. Thetissues shown to contain this lectin were further investigatedby immunohistochemical staining of the sections. Cells weredistributed in the connective tissue and in the interstice,particularly the dermis and subcutaneous layer of skin. Cellslocalized in the epithelium of skin (epidermis) or other epitheliathat we examined were not stained. Perivascular localizationof cells stained with mAb LOM-14 was also demonstrated in cardiacand skeletal muscle tissues. Immunoelectron microscopy revealedthe presence of this lectin along the rough endoplasmic reticulum.In conclusion, the distribution of C-type lectin specific forgalactose/N-acetylgalactosamine in mice was unique. The connectivetissue-specific distribution should provide important informationon the biological role of this lectin. lectin macrophage calcium-type lectin connective tissue     

The release of monovalent counterions by addition of divalent counterions in coulombic interaction system

The additivity rule of counterion activity or osmotic pressure in rodlike polyelectrolyte solutions has been discussed on the basis of the Fokker-Planck and Poisson equations in relation to the fluctuation of counterion distribution. This new theory has concluded that the additivity rule of counterion activity is less applicable than that of osmotic pressure due to the electric expansion force acting on the free-volume surface resulting from the fluctuation of counterion distribution. The theory has introduced an approximate relation between the counterion activities in the mixture solution of divalent and monovalent counterions, such that Deltaa+ = DeltaC++ - Deltaa++, in which Deltaa+ represents the increase of activity of monovalent counter-ions resulting from the addition of divalent counterionsDeltaC++, (in molar) to the solution, and Deltaa++ means the increase of the divalent counterion activity (in molar) in this process. This relation has been experimentally examined for Na-PSS solutions in the process of Cu2+ ion addition by the use of Na+ and Cu2+ sensitive electrodes, and it has been turned out that the relation is established in the low charge state of polyion.     

The release of monovalent counterions by addition of divalent countemons to aqueous solutions of maleic acid copolymer

Divalent cation binding and the release of monovalent cations accompanying the cation binding were experimentally studied by ion-selective electrode methods in aqueous solutions of copolymer of maleic acid and ethyl vinyl ether. It was found that in the process of Ca2+ addition, all the Ca2+ added was bound to polyions and the initially condensed Na+ was released in proportion to the concentration of the added Ca2+ up to the critical concentration of added Ca2+ at which the condensation of Ca2+ ceases. Values of the structural charge density parameter xi(s), were determined from the end-points of condensation of Ca2+. The process of Na+ release by adding Ca2+ was analyzed on the basis of the counterion condensation theory by using these xi(s) values. In addition, the relationship between the activity coefficient gamma-- of Ca2+ and degree of neutralization alpha in salt-free solutions was obtained from the Manning theory. Agreement between the calculated and experimental values was excellent in both cases.     

Reconstruction of mandibular defects with revascularized free rib grafts.

Two cases of hemimandibular reconstructions with revascularized free rib grafts are presented. The viability of the transplants was confirmed by bone scans and biopsy, even though the main nutrient vessels providing the intramedullary blood flow were not included in these grafts (and only the periosteal circulation was utilized). The removal of a rib graft without the nutrient vessel eliminates the need for a complicated posterior dissection, close to the costovertebral joint. Revascularized free bone grafts have a greater chance of survival, provide more rapid healing, offer less risk of absorption, and are more resistant to infection than conventional bone grafts.     

Association of neutral α-glucosidase with cytoplasmic granules of peritoneal macrophages

A neutral α-glucosidase (EC 3.2.1.20) activity was shown to be associated with granules which are sedimentable at 10 000 g after differential centrifugation of mouse peritoneal macrophage homogenates. When the post-nuclear supernatant was centrifuged in a sucrose density gradient, high activities for neutral α-glucosidase and β-glucuronidase (EC 3.2.1.31) were detected in the bottom fractions because of aggregation of the granules. Neutral α-glucosidase-containing granules were completely disaggregated by the addition of 20 units/ml of heparin and 10 mM Tris-HCl (pH 7.2), which caused only a partial disaggregation of β-glucuronidase-containing granules. The addition of a high concentration of heparin, Tris buffer, or KCl to the gradient gave the same patterns of disaggregation of the granules. Under the condition in which about 50% of the total β-glucuronidase activity was released into the medium, depending on phagocytosis, very little α-glucosidase was released. These observations suggested that neutral α-glucosidase may localize in non-lysosomal granules.     

Cyclic GMP-dependent protein kinase stimulates the plasma membrane Ca2+ pump ATPase of vascular smooth muscle via phosphorylation of a 240-kDa protein.

The plasma membrane Ca2+ pump ATPase from porcine aorta was isolated by the calmodulin affinity chromatographic method of Kosk-Kosicka et al. (Kosk-Kosicka, D., Scaillet, S., and Inesi, G. (1986) J. Biol. Chem. 261, 3333-3338). Its activity was restored by adding either phosphatidylcholine or phosphatidylserine. Cyclic GMP-dependent protein kinase (G-kinase) stimulated the enzyme in a concentration-dependent manner. However, phosphatidylinositol kinase (PI-kinase) activity was not detected in the enzyme preparation, and the presence of phosphatidylinositol was not necessary for stimulation by G-kinase. Furthermore, adenosine, a potent PI-kinase inhibitor, did not affect the stimulation. The enzyme preparation contained three major proteins, with molecular masses of 240, 145, and 135 kDa, as assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The 240- and 135-kDa proteins were phosphorylated in association with the stimulation by G-kinase, but only the phosphorylation of the 240-kDa protein was dependent on the G-kinase concentration. A purified enzyme without the 240-kDa protein, prepared by our previous method (Imai, S., Yoshida, Y., and Sun, H.-T. (1990) J. Biochem. (Tokyo) 107, 755-761), was not activated by G-kinase. Immunoblotting with an antibody against the human erythrocyte Ca2+ pump revealed that the 135-kDa protein corresponded to one of the isoforms of the plasma membrane Ca2+ pump. These results suggest that the phosphorylation of the 240-kDa protein is responsible for stimulation of the plasma membrane Ca2+ pump ATPase by G-kinase.