Microtubules Orient the Mitotic Spindle in Yeast through Dynein-dependent Interactions with the Cell Cortex

Proper orientation of the mitotic spindle is critical for successful cell division in budding yeast. To investigate the mechanism of spindle orientation, we used a green fluorescent protein (GFP)–tubulin fusion protein to observe microtubules in living yeast cells. GFP–tubulin is incorporated into microtubules, allowing visualization of both cytoplasmic and spindle microtubules, and does not interfere with normal microtubule function. Microtubules in yeast cells exhibit dynamic instability, although they grow and shrink more slowly than microtubules in animal cells. The dynamic properties of yeast microtubules are modulated during the cell cycle. The behavior of cytoplasmic microtubules revealed distinct interactions with the cell cortex that result in associated spindle movement and orientation. Dynein-mutant cells had defects in these cortical interactions, resulting in misoriented spindles. In addition, microtubule dynamics were altered in the absence of dynein. These results indicate that microtubules and dynein interact to produce dynamic cortical interactions, and that these interactions result in the force driving spindle orientation.     

A comparison of viable counts and adenine nucleotide analysis to determine the effect of antimicrobial agents on dental plaque

The effects of three antimicrobial agents on smooth surface dental plaque in monkeys were assessed using a plaque index, bacterial viable count, and adenine nucleotide analysis. The effects of the agents were revealed equally well when, viability was assayed by extractable adenosine triphosphate (ATP) or conventional viable cell counts. A persistent effect of one of the agents was revealed by both viable count and extractable ATP. These interpretations were supported by calculations of adenylate energy charge from the adenine nucleotide content of the smooth surface dental plaque samples.     

Cytological identification of the genomes in pentaploidAllium neapolitanum using Giemsa C-banding

Two homoeologous sets of chromosomes in pentaploidAllium neapolitanum Cyr. (Liliaceae) are recognizable by their C-bands. The banding pattern is the same for one Californian and five Yugoslavian populations, suggesting a common chromosomal origin. Predominant meiotic association of identically banded homologues indicates a genomic formula of AA A_I BB, confirms an allopolyploid origin, and argues against genetically controlled pairing.     

Electronmicroscopical detection of iota-Carrageenan as its ruthenium red complex

Summary Specific detection of iota-Carrageenan (i-CAR) at the ultrastructural level has been obtained by coupling with ruthenium red (RR) — an electron microscopic stain. The i-CAR-RR complex showed electron density on carbon layers. Peritoneal macrophages were treated with the complex and after 3 h it caused the same morphological changes in macrophages as iota-Carrageenan alone. On the surfaces of macrophages, fine filamentous electron dense material — the i-CAR-RR complex — was detected.     

Lectin Binding to Radopholus citrophilus and R. similis Proteins

Lectin-binding glycoproteins in seven populations of two burrowing nematode sibling species were probed with five different biotinylated lectins on Western blots, and differences were correlated with nematode ability to parasitize citrus and to overcome citrus rootstock resistance. Banding patterns of molecular weight standards were fit best by an exponential decay function, and a predictive equation was used to estimate molecular weights (r² = 0.999). A band (131 kDa) that labeled with the lectin Concanavalin A (Con A) occurred in extracts from cuticles and egg shells of populations of Radopholus citrophilus that parasitize citrus. Wheat germ agglutin labeled a band (58 kDa) in aqueous homogenates of populations that reproduce in roots of citrus rootstock normally resistant to burrowing nematodes. The two sibling species R. citrophilus and R. similis were distinguished by a high molecular weight Con A-labeled band (608 kDa) from cuticle and egg shells. Probing blots with the lectin Limulus polyphemus agglutinin indicated that each population contained a band (12-16 kDa) specifically inhibited by the addition of 25 mM neuraminic acid, suggesting that glycoproteins with sialic acid moieties are present in burrowing nematodes.     

Adoptive chemoimmunotherapy of a syngeneic murine lymphoma with long-term lymphoid cell lines expanded in T cell growth factor

Summary Recently techniques have been developed for the long-term growth of cytotoxic T-lymphoid cells in vitro with T cell growth factor (TCGF). We have investigated the use of these in vitro-expanded T cells for the immunotherapy of a disseminated syngeneic murine FBL-3 lymphoma. In this model, mice with disseminated tumor were treated on day 5 with 180 mg cytoxan/kg and then 5 h later were given lymphoid cells IP. In vivo-immunized lymphocytes resulted in significantly improved survival in three of three experiments, curing 52% of 38 animals, compared with treatment with cytoxan alone (0 of 31 cured) or cytoxan plus unimmunized cells (0 of 40 cured) (P<0.0005). In vivo-immunized lymphocytes were re-exposed to FBL-3 tumor in vitro for 5 days in complete medium (CM) or lectin-free TCGF (LF-TCGF). Both groups showed significantly improved survival in six of six experiments. Cytoxan cured 17% of 66 animals, while cytoxan plus normal lymphocytes after IVS cured 6% of 47 animals. In vivo-immunized cells resensitized in vitro to FBL-3 in CM or LF-TCGF cured 82% of 50 animals (P<0.001) and 72% of 61 animals (P<0.001), respectively. Cells from in vivo- and in vitro-sensitized lymphocytes exhibited no cytotoxicity in our in vitro ⁵¹Cr-release assay; expansion of these cells resulted in significant specific lysis of fresh FBL-3 targets. Adoptive transfer of immune lymphocytes resensitized to FBL-3 tumor in vitro and expanded in LF-TCGF conferred a significant survival benefit (P<0.001, curing 7 of 27 animals) compared with all controls. These expanded cells were then continuously grown in LF-TCGF for 2 1/2 months. Again, in vivo-immunized lymphocytes resensitized to FBL-3 tumor and expanded in LF-TCGF for 2 1/2 months cured 56% of the animals with disseminated tumor, significantly prolonging survival over that recorded in any control group (P<0.0002). Irradiation of these same cells totally abolished their efficacy. Clones were generated from IVS and continuously grown in LF-TCGF. Two of these clones were very cytotoxic for fresh FBL-3 (>4,000 lytic units/10⁶ cells). When adoptively transferred to mice in this chemoimmunotherapy model these cytotoxic clones significantly enhanced survival over that recorded following treatment with cytoxan alone (P<0.00001), though prolongation of survival was small. Implications of these results for application of these techniques to other less antigenic tumors and human cancers are discussed.     

Factors affecting population density, group size and territory size of the European badger, Meles meles

This paper discusses the relationship between the distribution and biomass of the main prey of European badgers, Meles meles and the badgers group size, territory size and population density. The distribution of areas rich in earthworms, Lumbricus spp., is correlated with badger range size, whilst badger group size increases with the biomass of worms per badger territory and badger density increases with overall worm biomass. Regulation of badger density in an area is likely to take place through regulation of group size, in the absence of other factors such as persecution and lack of suitable sett-sites.     

Mendelian analysis of the organization of actin sequences in Physarum polycephalum

The genormic organization of the multiple actin DNA sequences in the lower eukaryote Physarum polycephalum was investigated by Mendelian mapping. Actin-homologous restriction endonuclease cleavage fragments detected by DNA blotting showed length polymorphisms when different strains were compared. These length polymorphisms were used as phenotypic markers for actin sequences in the genome. The meiotic assortment of the polymorphic restriction fragments was analysed, revealing four unlinked actin loci. The data for three-of the actin loci, ardB, C and D, are consistent with a single sequence or gene at each locus. The data for the other actin locus. ardA, is consistent with multiple linked actin sequences or genes.     

Cerebral Synaptic Transmission During Anoxia Is Protected by Creatine

Synaptic transmission in cerebral tissue fails very rapidly in the absence of oxygen; the metabolic basis for this is not known. We report here that the transmission failure in the guinea pig hippocampal slice can be delayed threefold by exposing the tissue to extracellular creatine (Cr) for 3 h. The improved survival is associated with an increase of tissue phosphocreatine (PCr) concentration. These data argue that the metabolic basis for synaptic transmission failure is a fall in tissue ATP concentrations. They also indicate a way to protect brain tissue against anoxic damage.