Indirect visualization of hematopoietic colony-forming stem cell (CFUs) as a possible target cell for Mycoplasma arthritidis

Utilizing specific rabbit antiserum against M. arthritidis together with complement, a portion of the marrow 7-day CFUs population of CBA mice infected with live mycoplasma organisms 1 day previously was shown to be inactivated. These cells might therefore be considered as candidate target cells for M. arthritidis. 11-day CFUs were unaffected by similar treatment.     

Osmotic adaptation of moderately halophilic methanogenic Archaeobacteria,and detection of cytosolicN,N-dimethylglycine

Methanohalophilus mahii SLP andMethanohalophilus halophilus Z-7982, two closely-related, moderately halophilic, methylotrophic methanogens, were tested for their adaptation to saline conditions. They grew in a wider range of salinities than previously reported, in a defined medium with as little as 0.1 M NaCl, and with a high as 4.0 M NaCl forM. halophilus and 4.5 M NaCl forM. mahii. Fastest growth occurred with 1.5 M NaCl forM. mahii and 1.0 M NaCl forM. halophilus. M. mahii also grew in media in which NaCl was replaced by sucrose or KCl as osmolytes up to the osmolal equivalent of 2 and 2.5 M NaCl (these media contained other sodium salts totaling about 0.1 M Na⁺). In media with either sucrose of KCl replacing NaCl,M. mahii grew fastest at osmolalities approximately equiosmolal to 1 M NaCl.M. mahii not only grew well at a wide range of osmosities, it also tolerated rapid shifts in osmolality. Cells subjected to a rapid 10-fold hypertonic shift resumed growth without a prolonged lag. When cells were subjected to a rapid 10-fold hypotonic shift, 90% of cells lysed, but the remaineder continued to swell with little further lysis during the next 45 min. Surviving cells resumed growth.Methanohalophilus strains grown in defined medium had low cytosolic Na⁺ concentrations; K⁺ concentrations were as high as 0.35 M. Organic osmotica in the cytosol include glycine betaine and larger amounts of N,N-dimethylglycine.     

Phosphate transport inClaviceps sp. strain SD-58

Summary Phosphate uptake inClaviceps sp. strain SD-58 was found to be linear for 20 min, proportional to cell density in mg/ml, energy dependent, and taking place against a concentration gradient with a K_m value of 45.45×10^–5 M. Osmotic shock treatment to the cell caused a reduction in phosphate uptake associated with the release of binding protein. Partial restoration of uptake was observed on incubation of osmotically shocked cells with shock fluid. The results are discussed with reference to the effect of phosphate on alkaloid synthesis inClaviceps sp. strain SD-58.     

Immunological comparison between albumins of three species of mice (genusMus)

Summary Three closely related species of short-tailed mice (Mus musculus musculus, M. spretoides andM. spicilegus) were tentatively discriminated using immunological techniques based on albumin cross-reactivity. Different fractionations of crude albumin antisera allowed the recovery of antibody populations specific to theM. m. musculus albumin, whereas antibody population differences do not seem to exist betweenM. spicilegus andM. spretoides. Moreover, immunoreactivities tested with native and S-carboxymethylated albumins revealed that species-specific antibodies correspond to antigenic determinants depending on the amino acid sequence (sequential determinants). The observed immunological differences are related to species divergence and albumin sequences.     

Red cell metabolism in red and grey kangaroos

Summary Glucose utilization, lactate production and glutathione regeneration were measured in the red blood cells of 2 species of Australian Marsupials, Eastern grey kangaroo (Macropus gigantus) and red kangaroo (Macropus rufus), and were found to be significantly lower in the red blood cells from grey than that of red kangaroos.The author wishes to thank Mrs T. Stephens, M. A. Gruca and A. Mulley for help in blood collection and laboratory work. This work was supported by a grant from the National Health and Medical Research Council of Australia.     

Distinction of influenza viruses of different host cell origin

Summary Influenza A viruses grown in different animal or human cells retain their antigenic make-up as tested by the usual immunological assays. With the aid of aSambucus nigra (L.) extract containing its lectins the viruses can be distinguished after one single passage in a different cell type by a change in their hemagglutinating properties. Binding of such lectins to influenza viruses may be a means for a more subtle classification, relating to the host cell origin of the virus.     

Agglutinins from aquatic insects—tumor cell agglutination activity

Agglutinins were identified in whole body extracts of aquatic insects by means of murine tumor cell agglutination, using sarcoma 180 ascites, Ehrlich, and MM-46 cells. Screening revealed agglutinins in 5 of 10 of the larvae tested, and in 2 of 6 of the water-dwelling adult insects;Gerris paludum insularis andGyrinus japonicus. Only the agglutinin from adultG. paludum also agglutinated human erythrocytes. An ascites tumor was converted into a solid form in vivo after administration ofG. paludum agglutinin. The observation that these aquatic insect agglutinins preferentially agglutinate tumor cells has considerable implications in terms of anti-tumor effects such as inhibition of cell proliferation and metastasis.Deceased.     

Novel oscillations in cell suspensions ofDictyostelium discoideum

Summary With a light-scattering technique, two novel rhythms were discovered in cell suspensions ofDictyostelium discoideum. One is a damped oscillation with a period of 2 to 2.5 min (at 23°C) induced by folate in EDTA-dissociated undifferentiated cells. The other is a sinusoidal oscillation with a period of about 12 min occasionally observed with late differentiated cells. Obviously, the repertoire of rhythms of this simple eukaryotic organism is larger than previously assumed.     

Oxidative stress in the moderately halophilic bacteriumDeleya halophila: Effect of NaCl concentration

The sensitivity ofDeleya halophila to oxidative stress caused by hydrogen peroxide (H₂O₂) was found to vary, depending on the NaCl concentration of the growth medium. Pretreatment of the bacteria at a low concentration of H₂O₂ (50 M) protected the cells against the lethal effects of higher levels (1–2 mM) of H₂O₂. Exposure ofD. halophila cells to 50 M H₂O₂ resulted in the induction of several proteins (hydrogen peroxide-inducible proteins, hips). However, the kinetics of induction, the extent of induction and the number of hips appear to be influenced by the salt concentration of the growth medium. Five of the hips exhibited apparent molecular masses identical to those of five heat shock proteins (hsps).     

Acetylcholinesterase activity in anAedes aegypti cell line

Summary Considerable acetylcholinesterase (AChE) activity was detected in anAedes aegypti established cell line. The enzyme is blocked by 10^–6 M eserine sulfate, displays excess substrate inhibition and slowly hydrolyzes butyrylthiocholine. A 2-fold stimulation of AChE activity was shown after 2 days exposure to 3×10^–7 M -ecdysone. AChE activity found in the fresh medium is the contribution of the fetal calf serum portion. A direct relationship between levels of serum and the AChE activity in the cultured cells was demonstrated.Acknowledgment. I wish to thank Dr J. Peleg of the Israel Institute for Biological Research for providing the starting culture ofAedes aegypti cells.     

Occurrence of biopterin in the wings ofMorpho butterflies

A blue fluorescent compound was isolated fromMorpho butterfly wings. Based on thin layer chromatographic, UV and CD-spectrophotometric and HPLC analyses, the blue fluorescent compound was identified as L-erythro biopterin. Biopterin is a major component of blue fluorescent pteridines in bothM. sulkowskyi andM. adonis. Pterin and isoxanthopterin can also be detected as minor components in these species. This paper is the first to report the presence of biopterin in butterfly wings.     

Dissociated cell suspensions ofCarcinus maenas Y-organs as a tool to study ecdysteroid production and its regulation

In vitro ecdysteroid production by dissociated Y-organ cells of the shore crabCarcinus maenas was characterized during short-term incubations. Under optimized conditions (M199 adjusted to crab osmolality and with the addition of 10% foetal calf serum), ecdysteroid production by dispersed cells increased linearly during 4-hour incubations, with little intra-assay variation. 25-deoxyecdysone was mainly produced. PurifiedCarcinus molt inhbiting hormone (CamMIH) produced a dose-dependent inhibition of ecdysteroid production by dispersed cells. The cells were about 50 times more sensitive than whole glands to MIH. Other structurally-related peptides were tested.     

Haemopoietic stem cell concentration and CFUs in DNA synthesis in bone marrow from different bone regions

Summary The concentration of colony-forming cells (CFUs) is about 40% less in sternal marrow than in the marrow of lumbar vertebrae and femora. Marrow of trabecular bones in lumbar vertebrae contains fewer mitotically active CFUs than marrow of trabecular bones in the femoral distal epiphysis and metaphysis, or the peripheral marrow near the cortical bone in the femoral diaphysis. Only a minor part of the variability of the results in the CFU-assay is due to differences in CFU-concentrations between individual donor mice; pooling of the cell suspensions does not substantially decrease variability. Specific pathogen-free mice yield the same results as BALB/c mice from conventional breeding.Acknowledgments. This work was performed with support of Euratom contract No. 233-771 BIO B. We thank L. Tessens for his excellent technical assistance.     

Mitotic cell cycle time in root meristems of tetraploid and related diploid pearl millet

Summary Mitotic cell cycle time was estimated from root meristems of tetraploid and related diploid stock (IP 1475) of pearl millet (Pennisetum typhoides). There is 38% increase in cell cycle time in tetraploid meristems compared of their related diploid stocks.Acknowledgment. The authors thank Dr. M. Krishna Rao for useful suggestions and UGC for financial assistance.     

Legionella pneumophila down-regulates MHC class I expression of human monocytic host cells and thereby inhibits T cell activation

Legionella (L.) pneumophila, the causative agent of Legionnaires disease, is an intracellular pathogen of alveolar macrophages that resides in a compartment displaying features of endoplasmatic reticulum (ER). In this study, we show that intracellular multiplication of L. pneumophila results in a remarkable decrease in MHC class I expression by the infected monocytes. During intracellular multiplication, L. pneumophila absorbs ER-resident chaperons such as calnexin and BiP, molecules that are required for the correct formation of the MHC class I complex. Due to reduced MHC class I expression, stimulation of allogeneic blood mononuclear cells was severely inhibited by infected host cells but cytotoxicity of autologous natural killer cells against Legionella-infected monocytes was not enhanced. Thus, reduced expression of MHC class I in infected monocytes may resemble a new immune escape mechanism induced by L. pneumophila.Received 22 November 2004; received after revision 27 December 2004; accepted 5 January 2005     

Replication pattern of double minutes derived from an insect cell line

Summary The DNA replication pattern of double minutes derived from an established cell line ofAedes albopictus is described. Although the vast majority of double minutes replicate semiconservatively once during the S phase, some double minutes appear to exhibit different pattern(s). Two theories are suggested as possible explanations of our findings.This work was supported by a grant from the Whitehall Foundation, Inc. awarded to A.B.M.     

Halbe haploide Chromosomenzahl im Hoden vonMyrmica sulcinodis Nyl. (Formicidae)

Summary In the testes ofMyrmica sulcinodis there are not only haploid and some diploid cells to be found, as in the testes ofM. ruginodis, M. sabulsti andM. rubida, but a large mass of cells that have only half the haploid chromosome number. The diploid chromosome number ofM. sulcinodis is 56, those of six otherMyrmica species are between 42 and 48.     

Inhibition of respiratory oxidation of reduced sulfur compounds by intact cells ofThiobacillus denitrificans (strain RT) grown on thiosulfate

Thiobacillus denitrificans strain RT, an obligate sulfur-oxidizing chemolithoautotroph, was grown under microaerophilic conditions with thiosulfate as the only energy source. The rates of tetrathionate, thiosulfate, elemental sulfur (S^o) and sulfite oxidation were measured respirometrically with an oxygen electrode, using actively growing cells. Cells oxidized thiosulfate, elemental sulfur (S^o) and sulfite, but not tetrathionate. The thiosulfateoxidizing activity and elemental sulfur-oxidizing activity (SOA) were almost totally inhibited by 50 M myxothiazol (>80%), an inhibitor of the quinone-cytochrome b region, and by 10 M of the uncoupler carbonyl cyanide m-chlorophenylhydrazone (CCCP) (>82%). Sulfite-oxidizing activity was also significantly inhibited (>60%) by 50 M myxothiazol and 10 M CCCP. 1 mM KCN totally inhibited (>90%) all respiratory activities. This study confirms that a sulfur-oxidizing activity appears during microaerophilic growth ofThiobacillus denitrificans strain RT on thiosulfate. The SOA is linked to the respiratory chain, probably releasing electrons in the quinone-cytochrome b region.To whom correspondence should be addressed. Submitted by R. Bachofen.     

Comparison of retinal pigment epithelium cell preparations from the bovine eye

Summary Retinal pigment epithelium (RPE) cells were collected from, bovine eyes using a new method. The cells were harvested by vortexing the RPE and underlying choroid in 0.05 M citrate phosphate buffer, pH 5. RPE cells recovered by this method were compared to a standard method by microscopic examination of cell integrity, estimation of total protein, and assay of 11-cis and all-trans retinyl ester hydrolase (REH) activities. Results suggest that this method collects RPE cells of good integrity and with a significantly higher protein yield than the conventional method. Additionally, a much higher retinyl ester hydrolase activity was noted. Therefore we propose that this procedure offers a new and convenient method in the collection of RPE proteins for certain purposes such as enzyme purification.     

Oenocyte and prothoracic gland activity inManduca sexta under varying photoperiod and light conditions

Summary Manduca sexta larvae were subjected to diapause-inducing and diapause-preventing photoperiods, using two types of fluorescents (Indorsun and Blacklight-blue). The oenocytes, prothoracic glands (PTG) and ecdysone levels were examined in 3-day-old 5th instar larvae, 2-day-old and 10-day-old pupae. Our results indicate that oenocytes and PTG cells tend to be more active under long photoperiods while oenocytes only are active under short photoperiods in pupae in diapause. UV light has a definite effect on oenocytes while PTG cells seem to be unaffected. Ecdysone and ecdysterone levels vary with PTG and oenocyte activity at the pupal stage. The significance of these findings is discussed.This work was supported by a research associateship to L.M. by the People's Republic of China and a grant from NSERC to B.J.R.P.