Colonial Morphology of Treponemes Observed by Electron Microscopy

The colonial morphology of three strains of cultivable, nonpathogenic treponemes including a human oral treponeme was examined by light and electron microscopy. Treponema phagedenis strains Kazan and Reiter produced large white colonies on the surface of solid media composed of sterility test broth, 0.9 to 3.1% agar, rifampin, and 12.5% rabbit or horse serum. A human oral treponeme, strain G7201, grew as diffused white zones on 0.9 to 3.1% agar plates. Under the cultural conditions employed agar concentrations slightly affected the time of appearance of colonies of the three strains of treponemes. When the colonies of these three strains were viewed by scanning electron microscopy, differences in their colonial morphology were observed. The 11-day-old colonies of human oral strain G7201 were very small, 5 to 15 μm in diameter, and had a slight irregular border. Kazan treponemes developed circular, entire and low convex colonies. Scanning and transmission electron microscopy revealed that the colonies of Reiter treponemes contained spherical forms almost up to 5 μm in diameter, each consisting of an outer membrane and a treponemal main body. They were very similar to the spherical bodies produced by strain G7201 in sucrose-containing broth.     

An Internal View of the Spherical Body of Treponema macrodentium as Revealed by Scanning Electron Microscopy

The osmium-dimethyl sulfoxide-osmium method for clear visualization of intracellular structure was used to observe the detailed inner structure of the spherical bodies produced in vitro by a human oral treponeme. Scanning electron microscopy of the cracked spherical body revealed no morphological differences between the outer and inner surfaces of the spherical body membrane, and that multiple folded or somewhat linear main bodies adhere closely to the inner surface. In addition, axial flagella partially free from the main bodies spread widely within the body to make a network, and a number of blebs ranging from approximately 1 μm to 0.2 μm in diameter were located near the terminal or subterminal areas of the main bodies. The origin of the blebs and the mechanism of spherical body formation are discussed.     

Transport and Fixation of Inorganic Carbon during Photosynthesis in Cells of Anabaena Grown under Ordinary Air: III. Some Characteristics of the HCO3--Transport System in Cells Grown under Ordinary Air

In cells of cyanobacterium Anabaena variabilis grown under ordinaryair (low-CO₂ cells), the transport of both CO₂ and HCO₃^–was significantly enhanced by Na⁺. This effect was pronouncedas the external pH increased. When low-CO₂ cells were treatedwith an inhibitor of carbonic anhydrase (CA), only CO₂ transportbut not HCO₃^– transport, was inhibited. The initial rateof photosynthetic carbon fixation as a function of the concentrationof internal inorganic carbon (IC) was practically the same irrespectiveof whether CO₂ or HCO₃^– was externally supplied. Theseresults suggest that IC is actively transported through theplasma membrane in a form of HCO₃^– probably by some transporterand that the transmembrane Na⁺ gradient is involved in thisIC transport system. Free CO₂ may be hydrated by CA to HCO₃^–and then transported to the cells by this transporter. On the other hand, CO₂ is actively taken up by cells grown withair containing 5% CO₂ (high-CO₂ cells) though the enhancingeffect of Na⁺ was much smaller in high- CO₂ cells than in low-CO₂cells. The initial rate of fixation as a function of internal IC concentrationindicated that the rate of the carboxylation reaction of accumulatedIC is higher in I0W-CO₂ cells than in high-CO₂ cells. The studieswith ethoxyzolamide indicated that even in low-CO₂ cells, CAdoes not function inside Anabaena cells. These results suggestthat inside the low-CO₂ cells of Anabaena, some mediator(s)facilitates the transport of IC to RuBPCase. (Received January 23, 1987; Accepted April 24, 1987)     

Cloning and expression of a functional fucose-specific lectin from an orange peel mushroom, Aleuria aurantia

Aleuria aurantia lectin (AAL) shows sugar-binding specificity for L-fucose. A λgt11 expression library was constructed from A. aurantia poly(A) RNA and screened with a polyclonal antiserum directed against AAL. An immunopositive clone carrying 1.3-kb EcoRI fragment was obtained. The fragment encoded AAL, but lacked a nucleotide sequence corresponding to the two amino-terminal amino acids. The 5′-terminal part of the fragment was replaced with a chemically synthesized DNA fragment and inserted into an expression vector to yield a plasmid pKA-1. Escherichia coli carrying pKA-1 expressed functional AAL and the recombinant AAL showed the same immunological properties as those of natural AAL.     

Roles of the complement receptor type 1 (CR1) and type 3 (CR3) on phagocytosis and subsequent phagosome-lysosome fusion in Salmonella-infected murine macrophages

Abstract The receptors involved in the recognition of Salmonella typhimurium and S. typhi by murine macrophages were identified, and their relevance to phagosome-lysosome fusion was also investigated. Phagocytosis of S. typhimurium by murine macrophages was dependent on the opsonization with normal fresh serum, although the opsonin had no triggering activity in phagosome-lysosome fusion. In contrast, the opsonization of S. typhi with normal fresh serum efficiently triggered both phagocytosis and following phagosome-lysosome fusion. Anti-murine CR1 antibody suppressed phagocytosis of S. typhimurium by 36%, whereas anti-CR3 antibody, mannan, and advanced glycosylation endproducts (AGE)-BSA all failed to prevent phagocytosis of S. typhimurium , suggesting that CR1 may only contribute to the recognition of S. typhimurium and may possibly play a minor role. Other receptors involved may also influence the outcome phagocytosis in terms of phagosome-lysosome fusion. In the case of S. typhi , only anti-CR3 antibody significantly inhibited not only phagocytosis of S. typhi but also following phagosome-lysosome fusion. Treatment with K76COONa, an inhibitor of C3bINA (I factor), resulted in a marked inhibition of phagosomelysosome fusion in S. typhi -infected macrophages, although no significant inhibition was observed on phagocytosis of S. typhi . These results suggest that S. typhimurium and S. typhi may be recognized at least in part by CR1 and CR3, respectively, and that the recognition by CR3 but not CR1 is functionally associated with subsequent phagosomelysosome fusion in murine macrophages.     

High-order structure of metaphase chromosomes: evidence for a multiple coiling model

When chromosome preparations made by the conventional air-drying method were processed with the OsO₄/TCH technique and examined by scanning electron microscopy (SEM), spiral structures in chromatids, which have been frequently observed to be present by light microscopy, were found to be composed of 30 nm fibres. In some portions these fibres appeared to be arranged in coils to form thicker fibres. When chromosome preparations were processed for SEM without air drying, chromosomes appeared to consist of fairly homogeneous thick fibrous structures measuring about 200 nm in diameter. In relatively condensed chromosomes, these 200 nm fibres appeared to be arranged perpendicular to the long axis of the chromatid. These findings suggest that chromatid spiral structures represent a regularly loosened state of the compactly spiralized 200 nm fibres which in turn consist of spiralized 30 nm fibres.     

Axial ligation of nitrogenous bases to five-coordinate chloro-meso-tetraphenylporphyrinatochromium(III)

The axial ligations of nitrogenous bases to the five-coordinate chloro-meso-tetraphenylporphyrinatochromium(III) [Cr(III)(TPP)(Cl)] were studied in a non-coordinating solvent, dichloromethane (CH₂Cl₂), by spectrophotometric methods. A correlation exists between log K for the axial ligation:

and pK_a for the N-donor ligand. This correlation suggests that ligand to metal σ bonding contributes to the complex formation, rather than does metal to ligand π back-donation.     

Forest succession in the subalpine region of Mt. Fuji,Japan

Subalpine forest succession was studied on Mt. Fuji, Japan, where various types of forests in different successional phases occur owing to volcanic action. Ninety stands were subjected to ordination using an index (SI) defined by the relative basal area and the life span of component woody species, and the cover of canopy layer of the sample stands. Two different sequences of sample stands were found. One was from deciduous scrubs, through Larix kaempferi forests and Abies forests, to Tsuga diversifolia forests, and the other from Abies-Tsuga thickets to Abies forests. Through analyses of the forest structure and composition, soil survey and identification of fallen logs, the former sequence was recognized as the primary sere and the latter as a regeneration sere following gap formation. During forest succession, basal area reached a maximum in the seral phase with a multi-layered structure. The Tsuga forests, whose understory is restricted to a moss layer, were regarded as the climax. The death or fall of Tsuga stems resulted in gaps, which were subsequently occupied by Abies-Tsuga thickets. The second Abies forests were distinguished from the ones in the primary sere by the occurrence of Dryopteris and Cacalia and the lack of Rhododendron in the understorey. Both Abies forest types included Tsuga saplings. Thus, a cyclic relation is supposed between Abies and Tsuga.Nomenclature follows Ohwi (1975) and Nakaike (1982) for vascular plants, Iwatsuki & Noguchi (1973) for mosses, Inoue (1981) for hepaticae, Kashiwadani (1981) for lichens, respectively. Abies veitchii, A. mariesii were lumped as Abies spp.I wish to express my sincere gratitude to Prof. Toshio Hamaya, Tokyo, for the cordial guidance and encouragement. I also thank Prof. M. Numata and Dr. M. Ohsawa, Chiba, Prof. K. Okutomi, Tokyo, Dr. K. Suzuki, Tokyo, Dr. M. Suzuki, Kanazawa, and Mr. H. Taoda, Kumamoto, for their valuable advice and discussions.     

Mode of antitumor action of recombinant human tumor necrosis factor on the sarcoma Meth A transplanted in the mouse

The mode of antitumor action of rHu-TNF was elucidated in BALB/c mice bearing Meth A fibrosarcoma 7 days after transplantation with respect to time course, dose-response relationships and selectivity of the effects. The maximal cytotoxic effect on tumor cells revealed by inhibition of DNA synthesis and maximal lesional effect on tumor vasculature revealed by change in blood pool-size in the tissue were detected at 30 min and I h after administration of rHu-TNF, respectively. The dose-response relationship between cytotoxic and tumoricidal effects of rHu-TNF was irrespective of administration route. ED₅₀s of these antitumor effects afteri.v. administration of rHu-TNF were about 50 times as high as ED₅₀s afteri.t. administration. ED₅₀ ofi.t. given rHu-TNF for vascular effect was about 20 times as high as that for cytotoxicity while ED₅₀ ofi.v. rHu-TNF for vascular effect was only 2–3 times as high as that for cytotoxicity. The whole body autoradiographies with [¹²⁵I] HSA giveni.v. to see the blood influx into tumor tissue and [¹⁴C]thymidine given i.v. to see DNA synthesis in the whole body after administration of rHu-TNF revealed that the distribution of radioactivity was markedly changed in the tumor alone without any detectable change in other whole body tissues.In conclusion, thein vivo antitumor effect of rHu-TNF giveni.t. ori.v., appears to be exerted through the direct action on Meth A sarcoma rather than indirectly on tumor vasculature. Under present conditions, the effect of rHu-TNF in the whole body tissues seems rather selective on cells and vasculature of the tumor.