Effects of cells of epithelial rests of Malassez and endothelial cells on synthesis of glycosaminoglycans by periodontal ligament fibroblasts in vitro

Cultures of fibroblast-like cells (PLF) and epithelial rest cells (PLE) prepared from explants of porcine periodontal ligament synthesized and secreted four glycosaminoglycans (GAG) in differing proportions. The PLF produced predominantly chondroitin sulfate (greater than 60%) with smaller amounts of hyaluronic acid (HA) (17%), dermatan sulfate (13%), and heparan sulfate (7%), whereas PLE produced predominantly HA (greater than 80%). In coculture and under conditions of reciprocal transfer of conditioned media neither cell type affected the other's GAG synthesis. Endothelial cells (EC), however, or their conditioned growth media, were able to stimulate increased GAG synthesis, especially HA, in PLF. A similar result was obtained with smooth muscles cells (SMC) cultured in EC growth media but here again PLE were unable to stimulate GAG synthesis by SMC. These findings suggest that the spectrum of GAG found in whole ligament results both from independent production by, and from interaction between, the different cell types within the ligament. The results also provide support for a general hypothesis that loose connective tissues, which are rich in HA, are formed and maintained under the influence of epithelial, including endothelial, cells.     

A comparison of the binding of imidazole to valence hybrid and methemoglobin: an assignment of individual heme reactivity

The ferric hemes of valence hybrid hemoglobins combine with imidazole in a manner analogous with the hemes of methemoglobin. Equilibrium studies show that imidazole binding to methemoglobin is minimally described by the sum of two independent processes (K₁ = 200 M^?1 and K₂ = 37 M^?1), both of which contribute equally to the observed difference spectrum. Using valance hybrid hemoglobins, which show single binding processes under similar conditions, it is possible to identify the high affinity sites in methemoglobin with the α chains and the low affinity sites with the β chains.Kinetic studies show that the valance hybrid hemoglobins react in a single exponential fashion with imidazole in contrast with methemoglobin which shows a biphasic reaction (k₁ = 85 M^?1 sec^?1k₂ = 25 M^?1 sec^?1). A comparison of the rates of reaction of the hybrids allows the assignment of the fast phase in methemoglobin to the β chains and the slow phase to the α chains.The heterogeneity of the imidazole reaction with methemoglobin occurs over the pH range 5.5–9.5 within which two ionization processes are discernable at pH 6.9 and 7.5.     

Kinetic studies on the cupric ion oxidation of sheep hemoglobin

The oxidation of sheep hemoglobin, in both the oxygenated and deoxygenated forms, by cuprous ions have been studied by spectrophotometric and stopped-flow techniques. Mixing of both the oxy and deoxy forms with excess Cu²⁺ leads to the rapid oxidation of the iron atoms of all four of the hem groups of the tetrameric protein, followed by the slow formation of hemichromes (low spin Fe^III forms of hemoglobin). Stopped-flow studies show that the oxidations follow simple monophasic kinetics with second-order rate constants of 65 and 310 M^?1 sec^?1 for the oxy and deoxy forms, respectively. Variable temperature studies yield Arrhenius activation energies of 43 for the oxy form and 113 kJ mole^?1 for the deoxy form. For each form of the protein the activation energy is very similar to the activation enthalpy. While the deoxy form is characterized by an activation energy and enthalpy that is more than twice the corresponding value in the oxy form. The activation entropies show highly significant differences being ?128 e.u. and 136 e.u. at 25°C for the oxy and deoxy forms, respectively.     

The relationship between frameshift mutagenicity and DNA-binding affinity in a series of acridine-substituted derivatives of the experimental antitumour drug 4′-(9-acridinylamino)methanesulphonanilide (AMSA)

The mutagenicity and DNA-binding affinity of members of a series of acridine-substituted derivatives of 4′-(9-acridinylamino)methanesulphonanilide (AMSA) have been compared. The series includes compounds ranging from highly active to inactive in the L1210 murine leukaemia. Binding to DNA was measured by an ethidium displacement technique, with a correction being made for acridine-induced quenching of ethidium. Mutagenicity was assessed by measuring the reversion frequencies of the frameshift tester strain Salmonella typhimurium TA1537 in liquid culture. The results indicate that maximum mutagenicity is found in a “window” of DNA-binding affinities between 10⁶ and 5 × 10⁶ M^?1 (determined at 0.01 ionic strength). Compounds with binding affinities below 10⁶ M^?1 generally lacked both antitumour and mutagenic activity, whereas those with affinities above 5 × 10⁶ M^?1 were active against L1210 leukaemia but virtually inactive in inducing frameshift mutations.     

A spectroscopic and electrochemical study of the interaction between copper (II) glycylglycyl-L-histidine-N-methylamide and iron (III) tetra-p-sulfophenylporphine

A binuclear complex has been produced by the reaction of an iron porphyrin (sodium tetra-p-sulfophenylporphine iron (III)-FeTPPS) with a copper metallo-tripeptide (copper (II) glycylglycyl-L-histidine-N-methylamide-CuGGH) in aqueous solution. The system has been characterized by electron spin resonance (ESR) spectroscopy, optical absorption spectroscopy, and electrochemical methods. Room-temperature ESR spectra of the copper complex and low-temperature ESR spectra of the iron porphine provide evidence for the formation of a binuclear complex. These findings are supported by absorption spectroscopy and electrochemical studies, and lead to a value of ca. 2 X 10(-3) M-1 (at room temperature) for the equilibrium constant for complex formation. The relevance of this system to the enzymic active site of mammalian cytochrome c oxidase is discussed.     

Rust fungi in the subantarctic islands of New Zealand

Twenty-four species of rust fungi known from Auckland Islands and Campbell Island are listed, together with details of their host plants. Several species are recorded for the first time in these subantarctic islands. Four species are newly described and illustrated, viz., Milesia polystichi-vestiti on Polystichum vestitum (Dryopteridaceae), Petersonia dracophylli on Dracophyllum longifolium (Epacridaceae), Puccinia austrina on Isolepis habra (Cyperaceae), and Puccinia chathamica on Carex trifida (Cyperaceae). Uredo inflatus is transferred to Uromyces (as Uromyces inflatus comb. nov.) following recognition of the spores on Anisotome latifolia (Apiaceae) as teliospores.     

Butterflies of the South Pacific

ABSTRACT

Larvae of the invasive mosquito Culex quinquefasciatus Say are morphologically similar to those of the native Culex pervigilans Bergroth, yet distinguishing these species can be hampered by morphological variations in Cx. quinquefasciatus. We present detail about the extent of these variations in an urban population of Cx. quinquefasciatus in Auckland. To aid in identification of this exotic species, we provide images of key diagnostic characters and some observed exceptions to these. Details regarding variation in diagnostic characters for < 3rd instar and 3rd/4th instar larvae are given. Of the nine characters used for identification, three were highly consistent (dorsal papillae, mantle plate, pecten teeth); each observed in > 90% of larvae, although these characters were not always visible. Other characters were less reliable, for instance, the expected position of seta 1a-S in relation to the pecten teeth was observed in < 10% of larvae. Further exploration of regional morphological variation in both Cx. quinquefasciatus and Cx. pervigilans is recommended, ideally with associated molecular characterisation.     

A new sorediate,fumarprotocetraric acid‐producing lichen species of Menegazzia (Parmeliaceae,Ascomycota) from New Zealand

A new sorediate lichen, Menegazzia hypernota Bjerke, is described from New Zealand. This new species is characterised by convex, crescent‐shaped to fabi‐form soralia that are occasionally associated with perforations; apothecia with 2‐spored asci; the small perforations; the numerous secondary lobules; the presence of inconspicuous, yellow spots in the internal cavity; and fumarprotocetraric acid as principal medullary constituent. Menegazzia caliginosa, a species associated with M. hypernota, is reported for the first time from the Auckland Islands.     

A scanning electron microscopic study of the luteo-follicular complex

Summary As observed by SEM, the repair of an ovulated mammalian follicle is accompanied by a sequence of morphogenetic processes. In the initial phase, a mass of cells and coagulated fluids forms at the site of rupture. Shortly thereafter, connective cells, recruited from the adjacent and subjacent connective tissue stroma begin to proliferate and to migrate over this mass such that in the rabbit, the entire site of disruption is covered by a layer of connective cells by approximately 2 days following ovulation. Coincident with the migration of the connective tissue, superficial cells from undisturbed lateral and basal areas of an ovulated follicle also proliferate and begin to migrate over the newly established connective tissue matrix. By approximately 4 days following ovulation in the rabbit, the surface of an ovulated follicle is repopulated by elements of the superficial epithelium. The formation of the underlying corpus luteum (corpora luted) involves characteristic morphological changes as granulosa cells transform into steroid secreting luteal cells. The luteal cells become organized into cords of cells which usually surround capillary vessels. When examined by SEM, the smooth-surfaced endoplasmic reticulum of the luteal cell is quite apparent and is observed to form a three-dimension network of anastomosing tubules which are continuous with the nuclear membrane. Variations in the appearance of the surface of the ovary which directly overlies corpora lutea were observed when the mouse, rat and rabbit were compared. The regression of corpora lutea involves the infiltration of the luteal mass by connective tissue and both degeneration and vacuolization of the luteal cells. The regressing corpus luteum is a honey-comb-like structure in which each space is occupied by a degenerating luteal cell.This work was supported by grants from the National Institutes of Health, Public Health Service (to J.V.B., no. HD-04274), and from Consiglio Nationale delle Ricerche (C.N.R., contracts nos. CT 76.01288.04 and CT 77.01921.4)     

Dual Capacity for Nutrient Uptake in Tetrahymena. II. Role of the Two Systems in Vitamin Uptake

SYNOPSIS Previously, we found that a mutant strain of Tetrahymena pyriformis without food vacuoles failed to grow unless the nutrient media were richly supplemented with vitamins and trace metals. Here we show that calcium folinate alone can replace the extra vitamin supplementation. The mutant requires ∼ 90-fold higher concentrations of folinate than the wild-type cells to give similar growth responses in a chemically defined medium. We infer that the food vacuole is an important route of uptake for this vitamin in the wild-type cells. We found no difference between mutant and wild-type cells in their requirements for nicotinic acid, pantothenic acid, riboflavin-monophosphate, and pyridoxal. We infer that an extravacuolar route contributes importantly to uptake of these 4 compounds.     

On‐land habitat preferences of female New Zealand sea lions at Sandy Bay,Auckland Islands

Terrestrial habitat is important for breeding in most pinnipeds. On land, most species remain near the shore, but New Zealand (NZ) sea lions, Phocarctos hookeri, often rest inland up to 1.5 km from the sea. Only three breeding areas of NZ sea lions exist today after the species was extirpated from its historical range (NZ mainland). The study was conducted at the Sandy Bay breeding colony, Auckland Islands, between December 2002 and March 2003. We used daily Global Positioning System locations of breeding females with pups and mapping in a Geographic Information System to determine terrestrial habitat use and preferences. Slopes less than 20° were preferred throughout the study. Females chose nursing sites with a seasonal change, preferentially based on the distance from the sea and habitat type. Comparisons with the other breeding colonies of NZ sea lions are presented and data are discussed in the context of the recolonization of the NZ mainland. Overall, the most suitable terrestrial habitat configuration for a breeding aggregation of NZ sea lions appears to be a sandy beach, with a wide area above high tide and moderate intertidal zone (for breeding), backed with vegetated sand dunes and forest on primarily flat terrain (for later dispersion).     

Aspects of the biology of Xanthocnemis zealandica and Austrolestes colensonis (Odonata: Zygoptera) at three ponds in the South Island,New Zealand

Abstract

Both Xantnocnemis zealandica McLachlan and Austrolestes colensonis White were univoltine, and emerged asynchronously. At Woodend Pond, in 1971, larval growth was divided into cohorts by the drying up of some larval habitats in summer and autumn. Larval development was continuous in the other (permanent) habitats. A. colensonis differed from X. zealandica in its oviposition sites and its ability to survive the winter in the egg stage. There were differences in the larval food of the two species reflecting their differing agility.     

Internalization of a C17α-alkynylestradiol-porphyrin conjugate into estrogen receptor positive MCF-7 breast cancer cells

We hypothesized that expression of nuclear estrogen receptor (ER) in hormone-sensitive breast cancer cells could be harnessed synergistically with the tumor-accumulating effect of porphyrins to selectively deliver estrogen-porphyrin conjugates into breast tumor cells, and preferentially kill tumor cells upon exposure to visible light. In this study we synthesized a conjugate of C_17α-alkynylestradiol and pyropheophorbide and demonstrated that this conjugate is internalized by ER-positive MCF-7 cells while pyropheophorbide did not, suggesting an ER-mediated uptake and internalization of the conjugate by incipient nuclear ER in MCF-7 cells. This study is a direct demonstration of our hypothesis about ER-mediated internalization of estrogen-porphyrin conjugates.     

In vivo anti-tumour activity of recombinant MVM parvoviral vectors carrying the human interleukin-2 cDNA

BACKGROUND: The natural oncotropism and oncotoxicity of vectors derived from the autonomous parvovirus, minute virus of mice (prototype strain) [MVM(p)], combined with the immunotherapeutic properties of cytokine transgenes, make them interesting candidates for cancer gene therapy. METHODS: The in vivo anti-tumour activity of a recombinant parvoviral vector, MVM-IL2, was evaluated in a syngeneic mouse melanoma model that is relatively resistant in vitro to the intrinsic cytotoxicity of wild-type MVM(p). RESULTS: In vitro infection of the K1735 melanoma cells prior to their injection resulted in loss of tumorigenicity in 70% of mice (7/10). Tumour-free mice were protected against a challenge with non-infected parental cells. In addition, MVM-IL2-infected tumour cells induced an anti-tumour activity on parental cells injected at a distant location. These non-infected tumour cells were injected either at the same time or 7 days before the injection of MVM-IL2-infected cells. In the latter setting, which mimics a therapeutic model for small tumours, 4/10 mice were still tumour-free after 4 months. CONCLUSIONS: Our results show that (i) the MVM-IL2 parvoviral vector efficiently transduces tumour cells; and (ii) the low multiplicity of infection (MOI = 1) used in our experiments was sufficient to elicit an anti-tumour effect on distant cells, which supports further studies on this vector as a new tool for cancer gene therapy.     

The ultrastructure of the cells of Leydig in the white-crowned sparrow (Zonotrichia leucophrys gambelii) in relation to plasma levels of luteinizing hormone and testosterone

In male White-crowned Sparrows subjected to 20 h daily photoperiods there is an approximately 3-fold increase in the plasma concentration of luteinizing hormone (LH) on the first long day after which a quasi-stable level is maintained for at least 42 days. This increase is followed by an increase in numbers of cells of Leydig and an enhancement of their steroidogenic features, a decrease in transitional interstitial cells, and an increase in plasma level of testosterone. With the decline in plasma LH, as photorefractoriness develops, the steroidogenic features of the cells of Leydig undergo disorganization. For as yet unexplainable reasons the plasma levels of testosterone decline before the decrease in plasma LH and before the degeneration of the steroidogenic features of the cells of Leydig.     

Synchronous cultures from the baby machine. A model for animal cells

A baby-machine system that produces newborn Escherichia coli cells from cultures immobilised on a membrane was developed many years ago in an attempt to attain optimal synchrony with minimal disturbance of steady-state growth, and a model designed to characterise the nature and quality of the synchrony of such cells in a quantitative manner has been published. The baby machine has now been adapted for animal cells, and the present article is an attempt to modify the model to include these cells as well. The model consists of five elements, giving rise to five adjustable parameters (and a proportionality constant): a major, essentially synchronous group of cells with ages distributed normally about zero; a minor, random component from a steady-state population on the membrane that had undergone only very little age selection during the elution process; a fixed background count, to allow for the signals recorded by the electronic particle counter produced by debris and electronic noise; a time-shift, to account for differences between time of cell division and end of sample collection; and the coefficient of variation of the interdivision-time distribution, taken to be reciprocal-normal. It is this last feature, a reciprocal-normal rather than a Pearson type III interdivision-time distribution, that distinguishes this version of the model from its predecessor. The model is fitted by unconstrained non-linear least-squares to data from three different leukemia cell lines. The standard errors of the parameters are quite small in all cases, making their estimates highly significant; the quality of the fit is striking. The five parameters of the model can be divided into two nuisance parameters, two that are associated with the methodology and one that describes an inherent property of the cell itself; it turns out that both methodology parameters are zero in all three data sets studied. We also discuss the partition of the transition-time dispersion between the age distribution of the newborn cells and the age distribution of dividing cells and show that a reliable estimate of the corresponding parameters requires an experiment that extends over at least two and a half doubling times.     

Tetraploid cells produced by absence of substrate adhesion during cytokinesis are limited in their proliferation and enter senescence after DNA replication

Tetraploidy has been proposed as an intermediate state in neoplastic transformation due to the intrinsic chromosome instability of tetraploid cells. Despite the identification of p53 as a major factor in growth arrest of tetraploid cells, it is still unclear whether the p53-dependent mechanism for proliferation restriction is intrinsic to the tetraploid status or dependent on the origin of tetraploidy. Substrate adherence is fundamental for cytokinesis completion in adherent untransformed cells. Here we show that untransformed fibroblast cells undergoing mitosis in suspension produce binucleated tetraploid cells due to defective cleavage furrow constriction that leads to incomplete cell abscission. Binucleated cells obtained after loss of substrate adhesion maintain an inactive p53 status and are able to progress into G1 and S phase. However, binucleated cells arrest in G2, accumulate p53 and are not able to enter mitosis as no tetraploid metaphases were recorded after one cell cycle time. In contrast, tetraploid metaphases were found following pharmacological inhibition of Chk1 kinase, suggesting the involvement of the ATR/Chk1 pathway in the G2 arrest of binucleated cells. Interestingly, after persistence in the G2 phase of the cell cycle, a large fraction of binucleated cells become senescent. These findings identify a new pathway of proliferation restriction for tetraploid untransformed cells that seems to be specific for loss of adhesion-dependent cytokinesis failure. This involves Chk1 and p53 activation during G2. Inhibition of growth and entrance into senescence after cytokinesis in suspension may represent an important mechanism to control tumor growth. In fact, anchorage independent growth is a hallmark of cancer and it has been demonstrated that binucleated transformed cells can enter a cycle of anchorage independent growth.