Invading cancer cells are predominantly in G0/G1 resulting in chemoresistance demonstrated by real-time FUCCI imaging

Invasive cancer cells are a critical target in order to prevent metastasis. In the present report, we demonstrate real-time visualization of cell cycle kinetics of invading cancer cells in 3-dimensional (3D) Gelfoam® histoculture, which is in vivo-like. A fluorescence ubiquitination cell cycle indicator (FUCCI) whereby G₀/G₁ cells express a red fluorescent protein and S/G₂/M cells express a green fluorescent protein was used to determine the cell cycle position of invading and non-invading cells. With FUCCI 3D confocal imaging, we observed that cancer cells in G₀/G₁ phase in Gelfoam® histoculture migrated more rapidly and further than cancer cells in S/G₂/M phases. Cancer cells ceased migrating when they entered S/G₂/M phases and restarted migrating after cell division when the cells re-entered G₀/G₁. Migrating cancer cells also were resistant to cytotoxic chemotherapy, since they were preponderantly in G₀/G₁, where cytotoxic chemotherapy is not effective. The results of the present report suggest that novel therapy targeting G₀/G₁ cancer cells should be developed to prevent metastasis.     

Contest and scramble competitions in two bruchid species,Callosobruchus analis andC. Phaseoli (Coleoptera: Bruchidae)

We performed multiple-generation competition experiments between Callosobruchus analis and C. phaseoli with different bean sizes. In each system, we supplied 5 g of mung beans (Vigna radiata) every 10 days. We examined three types of bean conditions: 5 g of large beans, 5 g of small beans, and a mixture of 2.5 g of large and small beans. In small bean condition, C. analis dominated C. phaseoli in all three replicates and C. phaseoli was extinct by the 260th day. On the contrary, C. phaseoli overcame C. analis within 250 days in large beans in all three replicates. In mixed beans condition the two bruchid species coexisted more than 500 days in two out of the three replicates. Even in the exceptional case, both species coexisted for 460 days. These results were examined in the light of the predictions from short-term larval competition experiments and a game theoretical model by Smith and Lessells (1985). The density and frequency dependent results during larval competition inside a bean was concluded to be a main factor to produce the above long-term competition results.     

Gas chromatographic—mass fragmentographic determination of homopantothenic acid in plasma

A gas chromatographic—mass fragmentographic method was developed for the determination of homopantothenic acid in plasma. Acidified plasma was deproteinized by extraction with chloroform and subsequently the aqueous layer was extracted with ethyl acetate. The organic layer containing homopantothenic acid was reduced to dryness, and the resulting residue was redissolved in N,O-bis(trimethylsilyl)trifluoroacetamide—pyridine solution to allow trimethylsilylation. Aliquots of this solution were injected into the gas chromatograph—mass spectrometer and analyzed by the selected ion monitoring method using l-ascorbic acid as an internal standard. The detection limit for homopantothenic acid was 5 ng/ml of plasma.A precise and sensitive assay for the determination of homopantothenic acid in plasma was established.     

D-alpha-Hydroxyglutarate dehydrogenase of Rhodospirillum rubrum.

D-alpha-Hydroxyglutarate dehydrogenase of R. rubrum grown anaerobically in the light was partially purified and some properties were investigated. 1. The enzyme catalyze stoichiometrically the dehydrogenation reaction of D-alpha-hydroxyglutarate into alpha-oxoglutarate, coupled with the reduction of 2, 6-dichlorophenolindophenol. 2. Cytochrome c2, cytochrome c, and ferricyanide are effective as electron acceptors with the crude enzyme but not with the purified one, whereas NAD+ and NADP+ are completely ineffective. The enzyme is thought to play a role in the electron transport system of the organism. 3. D-alpha-Hydroxyglutarate is virtually the sole substrate for the enzyme. The apparent activity against L-alpha-hydroxyglutarate is presumed to be due to contamination of the L-isomer sample with the D-isomer. The enzyme shows barely detectable activity against both isomers of malate and virtually no activity against DL-lactate and glycolate. 4. Both isomers of malate and oxalate, which are presumably substrate analogues, inhibit the enzyme activity. 5. The enzyme is not an inducible enzyme but rather is a constitutive one for R. rubrum, unlike from the enzyme of Pseudomonas putida which is an inducible enzyme for the catabolism of lysine.     

Detection and chemical identification of natural bio-antimutagens: A case of the green tea factor

A bio-antimutagen, isolated from Japanese green tea (leaves of Camellia sinensis), reduced high spontaneous mutations due to altered DNA-polymerase III in a mutator srain of Bacillus subtilis. Chemical studies showed that the factor was epigallo-catechin-gallate (EGCg).     

A new method for selective N-acylation of aminoglycoside antibiotics

Per-N-formylation of aminoglycoside (aminocyclitol) antibiotics followed by mild hydrolysis with aqueous ammonia gave mono-N-deformylated derivatives. Each positional isomer of the mono-N-deformylated derivatives thus obtained was separated by column chromatography on Amberlite CG-50 (NH₄⁺ ). Acylation of mono-N-deformylated derivatives gave the corresponding mono-N-acylated derivatives. The N-formyl groups of the mono-N-acylates were removed by the treatment with dilute aqueous hydrazine acetate, whereas the newly introduced N-acyl group was stable under these conditions. The 1-N-formyl group of the deoxystreptamine moiety of per-N-formylated aminoglycoside antibiotics containing neamine (or 3′-deoxyneamine) is more readily deformylated than the 3-N-formyl group. In this report, isolation and structural-elucidation studies, including ¹³C-n.m.r. spectral assignments, of positional isomers of tri-N-formyl derivatives of xylostasin (1), 3′-deoxyxylostasin (2), kanamycin A (3), and neamine (4) are described. This selective N-acylation provides a useful method for the preparation of 1-N-modified derivatives, and the synthesis of 3′-deoxybutirosin A (2f) from 2 is described in detail as an example.     

Evolution of generosity in the demand game

An ecological system often requires moderate, and sometimes even generous interactions among constituents for achieving a sustainable coexistence. Here we propose a configuration individual-based model for demonstrating the evolution of generosity in an evolutionary demand game. In the game, two players, proposers and responders, simultaneously make their demands. If the sum of demands is no more than the total amount of the available resource at each game, each player obtains its own demand. However, both players get nothing if the sum exceeds the total amount. We incorporated generosity by discounting players demands. In every generation, random pairs were formed, and each pair played the demand game. For the next generation, individuals left a number of offspring proportional to their total payoff. Demand and generosity levels of an individual were inherited by its offspring with slight modification by a small random mutation. When only proposers were allowed to discount their demands, distribution of generosity levels had its mode at zero, and hence generosity did not evolve. However, when both proposers and receivers were allowed to discount their demands, the mean generosity level rose from zero. The resultant populations were not homogeneous, but were made of heterogeneous individuals with high and low generosity levels. Mean demand and generosity levels fluctuated greatly because of the neutral selection for the demand and generosity combinations that equally maximized the payoff of the demand game. Spatially limited interaction increased generosity levels even if only proposers discounted their demands.     

The ESC-E(Z) complex participates in the hedgehog signaling pathway

Polycomb group (PcG) genes are required for stable inheritance of epigenetic states throughout development, a phenomenon termed cellular memory. In Drosophila and mice, the product of the E(z) gene, one of the PcG genes, constitutes the ESC-E(Z) complex and specifically methylates histone H3. It has been argued that this methylation sets the stage for appropriate repression of certain genes. Here, we report the isolation of a well-conserved homolog of E(z), olezh2, in medaka. Hypomorphic knock-down of olezh2 resulted in a cyclopia phenotype and markedly perturbed hedgehog signaling, consistent with our previous report on oleed, a medaka esc. We also found cyclopia in embryos treated with trichostatin A, an inhibitor of histone deacetylase, which is a transient component of the ESC-E(Z) complex. The level of tri-methylation at lysine 27 of histone H3 was substantially decreased in both olezh2 and oleed knock-down embryos, and in embryos with hedgehog signaling perturbed by forskolin. We conclude that the ESC-E(Z) complex per se participates in hedgehog signaling.     

Negatively charged phospholipids suppress IFN-gamma production in T cells

The effect of phospholipids on IFN-gamma production in mouse T cells was investigated. Phosphatidylserine (PS), which has a negatively charged head group, completely inhibited IFN-gamma production in splenic na?ve T cells and antigen-dependent IFN-gamma production in Th1 clone 42-6A cells, whereas other phospholipids, which have neutrally charged head group, had no effect. The structural requirements for IFN-gamma inhibitory effects by PS were investigated, and dimyristoyl-PS (C14: 0) and dipalmitoyl-PS (C16: 0) had no effect on IFN-gamma production, and interestingly, distearoyl-PS (18: 0) increased IFN-gamma production. Dioleoyl-PS (C18: 1), dilinoleoyl-PS (C18: 2), and oleoyl-lyso-PS (C18: 1) completely inhibited IFN-gamma production. To clarify this mechanism, we focused on the stability of IFN-gamma mRNA, and the treatment of splenic na?ve T cells with PS brought about 40% reductions in IFN-gamma mRNA expression in the presence of actinomycin D. Collectively, IFN-gamma inhibitory effects by PS are highly dependent on the molecular structure of PS and involve the decreasing of the stability of IFN-gamma mRNA.     

Effects of temperature, salinity and irradiance on the growth of the harmful red tide dinoflagellate Cochlodinium polykrikoides Margalef (Dinophyceae)

The effects of temperature, salinity and irradiance on the growthof the harmful red tide dinoflagellate Cochlodinium polykrikoideswere examined in the laboratory. From 60 different combinationsof temperature (10–30°C) and salinity (10–40)under saturated irradiance, C. polykrikoides exhibited its maximumspecific growth rate of 0.41 day^-1 at a combination of 25°Cand salinity of 34. Optimum growth rates of >0.3 day^-1 wereobserved at temperatures ranging from 21 to 26°C and atsalinities from 30 to 36. The organism did not grow at temperatures10°C and only grew at salinities >30 if the temperaturewas >15°C. It was able to grow in temperatures rangingfrom 15 to 30°C and at salinities from 20 to 36. These valuesclosely resembled those observed for this species in situ. Itappears as if C. polykrikoides is a stenohaline organism thatprefers high salinities, indicative of offshore waters. Temperaturehad the greatest influence on the growth rate, followed by salinity,and then the interaction between temperature and salinity. Theoptimum irradiance for growth was >90 µmol m^-2 s^-1.Photoinhibition did not occur at 230 µmol m^-2 s^-1, whichwas the maximum irradiance used in this study.