Interaction of human Waldenstr?m's IgM proteins with guinea pig and human complement.

The activity of purified human Waldenstr?m's IgM protein to fix complement of human and guinea pig origins was compared at different temperatures using the polystyrene latex particle-adsorption method. It was shown that the interaction of the IgM proteins with complement differed depending on the source of complement and that a pronounced heterogeneity in complement-fixing activity was observed among the IgM proteins when tested with guinea pig complement. Thus, by the use of guinea pig complement, six human IgM proteins examined were classified roughly into two groups, one having a high and the other a low activity at 3 C as well as at 37 degrees C. With human complement, five proteins showed a rather uniform activity at 37 degrees C. However, there was one protein with no detectable activity, suggesting the presence of non-complement-fixing protein in the IgM class. All the six proteins showed no significant activity with human complement at 3 C. No antigenic difference has been found as yet in the Fc or Cmu2 region among these IgM proteins examined.     

High SO2 resistance ofClethra barbinervis established in a smoke-polluted area of Ashio,Tochigi Prefecture,Japan

The effect of SO₂ on the photosynthesis ofClethra barbinervis collected from a smoke-polluted area near the Ashio copper smelter in Tochigi Prefecture was compared withC. barbinervis collected from a nonpolluted district in Tsukuba, Ibaraki Prefecture andQuercus mongolica var.grosseserrata grown in a nonpolluted field in Nagano Prefecture. The plants were exposed to 0.5–1.5 p.p.m. SO₂ for 90 min (short-term) and to 0.3 p.p.m. SO₂ for 31–39 days (long-term). TheClethra plants from both sites had a lower intrinsic stomatal conductance and photosynthetic rate thanQuercus plants. Short-and long-term fumigation caused stomatal closure inQuercus plants, but had little effect on the stomatal conductance ofClethra plants. Under short-term fumigation, nonstomatal photosynthetic inhibition per unit of absorbed SO₂ was smallest inClethra plants from Ashio. Long-term fumigation caused photosynthetic decline and visible foliar injury toQuercus plants, but had no effect onClethra plants from Ashio. Consequently,Clethra plants from Ashio had a higher photosynthetic rate thanQuercus plants after long-term fumigation. These results suggest thatC. barbinervis populations in the smoke-polluted area of Ashio had evolved high SO₂ resistance connected with SO₂ detoxification ability in mesophyll cells.     

Enhanced leukotriene C4 synthase activity in thioglycollate-elicited peritoneal macrophages

The utilization of LTA4 by peritoneal macrophages (MO) obtained from untreated rats (control) as well as by those elicited from rats was investigated at designated intervals (on days 3, 7, and 14) following the intraperitoneal injection of thioglycollate (TG). On day 7 following the injection the elicited MO converted LTA4 to LTC4 at the highest rate while the resident MO showed the lowest rate. The conversion of LTA4 to LTC4 and LTB4 was next examined by using each MO lysate. The apparent LTC4 synthase activity was significantly higher in the MO lysate both on day 3 and day 7, with the latter being the highest value obtained. The GSH S-transferase activity in each lysate using as the substrate, DNCB was significantly lower on day 3 but significantly higher on day 7 as compared to control values. However, this elevated activity was less variable than that observed with LTC4 synthase. The possible implication for these observations is discussed.     

The non-osteogenic mouse pluripotent cell line, C3H10T1/2, is induced to differentiate into osteoblastic cells by recombinant human bone morphogenetic protein-2.

The possibility that the non-osteogenic mouse pluripotent cell line, C3H10T1/2 (10T1/2), could be induced to differentiate into osteogenic cells by various hormones and cytokines was examined in vitro. Of a number of agents tested, recombinant human bone morphogenetic protein-2 (rhBMP-2) and retinoic acid induced alkaline phosphatase (ALP) activity in 10T1/2 cells. rhBMP-2 also induced mRNA expression of ALP in the cells. Dexamethasone, 1 alpha, 25-dihydroxyvitamin D3, transforming growth factor-beta 1 and insulin-like growth factor-I did not stimulate ALP activity. Treatment with rhBMP-2 greatly induced cAMP production in response to parathyroid hormone in 10T1/2 cells. No ALP activity was induced in NIH3T3 fibroblasts treated with rhBMP-2 or retinoic acid. These results indicate that 10T1/2 cells have a potential to differentiate into osteogenic cells under the control of BMP-2.     

A Cl(-)-translocating adenosinetriphosphatase in Acetabularia acetabulum. 2. Reconstitution of the enzyme into liposomes and effect of net charges of liposomes on chloride permeability and reconstitution

The Mono Q-III fraction, a Mg2(+)-ATPase, isolated from Acetabularia acetabulum was reconstituted into liposomes of various net charges prepared by the reversed-phase method and tested for a Cl(-)-translocating activity. The liposomes from a mixture of egg lecithin, dicetyl phosphate, and cholesterol (63:18:9 mole ratio, negative liposomes) and from a mixture of egg lecithin and cholesterol (63:9 mole ratio, neutral liposomes) were less leaky than positive liposomes from asolectin, and from a mixture of egg lecithin, stearylamine, and cholesterol (63:18:9 mole ratio). A significant increase in 36Cl- efflux from the negative and neutral liposomes was observed by addition of ATP in the presence of valinomycin after incorporation of the enzyme by short-term dialysis. The ATP-driven 36Cl- efflux was inhibited by addition of azide, an inhibitor of the ATPase. The preincubation of the enzyme with phenylglyoxal, an arginine-modifying reagent, inactivated ATP-mediated 36Cl- efflux, but the ATPase activity of the preparation was not affected. When chloride was replaced by 35SO4(2)-, no ATP-dependent 35SO4(2)- efflux was detectable from the proteoliposomes. Proton-translocating activity of the enzyme was also tested, and no fluorescent quenching of 9-ACMA was observed.     

A Cl(-)-translocating adenosinetriphosphatase in Acetabularia acetabulum. 1. Purification and characterization of a novel type of adenosinetriphosphatase that differs from chloroplast F1 adenosinetriphosphatase

ATPases were solubilized from membranes of Acetabularia acetabulum using nonanoyl-N-methylgluconamide and purified by ion-exchange and gel permeation chromatography. Three fractions of ATPase, Mono Q-I, -II, and -III, were separated. Activity in fraction Mono Q-I was very labile and could not be accurately determined. Fractions Mono Q-II and -III had specific activities of 0.6 and 6 units/mg of protein, respectively. By SDS-polyacrylamide gel electrophoresis, isoelectric focusing, and peptide mapping, it was shown that fractions Mono Q-II and -III consisted of the same polypeptides with molecular masses of 54K (a-subunit) and 50K (b-subunit). Fractions Mono Q-II and -III had the following catalytic properties: pH optimum at 6.0; substrate specificity, ATP = GTP = ITP much greater than UTP = CTP (Km for ATP 0.6 mM); divalent cation requirement, Mn2+ = Mg2+ greater than Co2+ greater than Zn2+ much greater than Ca2+, Ni2+. Both activities were inhibited by monovalent anions, while monovalent cations had neither inhibitory nor stimulatory effects. Orthovanadate inhibited both activities to 50% at 1 mM, and the most effective inhibitor of both was azide (95% inhibition at 100 microM). An enzyme-phosphate complex was formed after incubation of fraction Mono Q-III with [gamma-32P]ATP. The CF1-ATPase subcomplexes were isolated from the same organism and compared with the fraction Mono Q-III. Data supported the difference of fraction Mono Q-III from CF1-ATPase.     

Kinetics and localization of parasite-specific IgE in Paragonimus ohirai-infected rats

Ikeda T., Oikawa Y. and Fujita K. 1982. Kinetics and localization of parasite-specific IgE in Paragonimus ohirai-infected rats. International Journal for Parasitology12: 395–398. In Wistar rats infected with Paragonimus ohirai (P.O.), P.O.-specific IgE responses of the mesenteric and mediastinal lymph nodes and spleen were determined by homologous adoptive cutaneous anaphylaxis (ACA) assay since P.o. -specific IgGa was not detected by either 2 h or 4 h PCA. Intraperitoneal (i.p.) infection with metacereariae elicited similar patterns of ACA response in the three lymphoid tissues examined, with the mediastinal lymph node giving the highest response. ACA positive cells were detected 2 weeks after infection, peaked at 3 weeks and then declined. These kinetics of ACA responses nearly paralleled the kinetics of serum P.o.-specific IgE titre. In intrapleural infection with metacereariae, on the other hand, the mediastinal lymph node gave a high ACA response comparable to the lymph node in i.p. infection, but the mesenteric lymph node and spleen gave negligible ACA responses. In infection established by i.p. transplantation of 4–5-week-old worms, only the mediastinal lymph node of the three lymphoid tissues responded and its response was at a low ACA level. The level of serum P.O.-specific IgE was much lower in the above two infections than in i.p. infection with metacercariae.     

Body shrinkage as a possible over-wintering mechanism of the Antarctic krill, Euphausia superba Dana

Antarctic krill (Euphausia superba Dana) were maintained successfully for 211 days without food. A significant reduction in body size (32.1–56.1% of initial wet wt) was observed. Compared with wild animals starved E. superba decreased their oxygen uptake, ammonia excretion and phosphate excretion considerably (24–52%), but no significant changes in wet: dry wt ratio, and chemical compositions (C, N, P) were observed. The mortality of the starved group was similar to that of controls fed Tetra Marin and frozen copepods and less than that of controls fed a mixture of microalgae (Dunaliella and Phaeodactylum). Because of insufficient lipid storage, E. superba is hypothesized to switch from herbivorous feeding to omnivorous or carnivorous during the Antarctic winter. The present results suggest, however, that body shrinkage could be an alternative way for this animal to conserve energy during the winter. The advantage of this is discussed in the light of the characteristics of body structure and life style of E. superba.     

Identification of estrogen-inducible growth factors (estromedins) for rat and human mammary tumor cells in culture

Summary The role of polypeptide growth factors (estromedins) as mediators of estrogen-responsive mammary tumor growth is studied in this report. Three possible new mechanisms were investigated that include endocrine, autocrine, and paracrine related growth factors. The first hypothesis being tested is whether estrogens interact with target tissues and cause the biosynthesis and secretion of polypeptide growth factors, which then act as mitogens for normal and neoplastic mammary tissues. Data presented suggest that this mechanism involves estrogen interaction with uterus, kidney, and pituitary gland causing production of growth factors, which then enter the general circulation and promote growth of distant target tissues. This is an endocrine type mechanism. Another type of estromedin control (autocrine control) may be exerted in an autostimulatory way in which the target tissue produces the polypeptide factors for its own growth in response to estrogen stimulation. A variation of the autocrine mechanism may be a paracrine mechanism in which some cells of an estrogen-responsive normal or neoplastic tissue produce growth factors that act on adjacent or neighboring cells. From the data available, all three possible types of growth factors could be functioning synergistically to yield the final result of continuous estrogen responsive tumor growth in vivo. Presented in the symposium on Plant and Animal Physiology in Vitro at the 33rd Annual Meeting of the Tissue Culture Association, San Diego, California, June 6–10, 1982. This work was supported by American Cancer Society Grant BC-255; D. A. S. is the recipient of an American Cancer Society Faculty Research Award, FRA-212. D. D. is supported by a Rosalie B. Hite predoctoral fellowship from the Rosalie B. Hite Foundation, Houston, Texas. This symposium was supported in part by the following organizations: Bellco Glass, Inc., California Branch of the Tissue Culture Association, Collaborative Research, Hana Media, Hybridtech, K C Biological, Inc., and Millipore Corporation.