KUD773, a phenylthiazole derivative,displays anticancer activity in human hormone-refractory prostate cancers through inhibition of tubulin polymerization and anti-Aurora A activity

Background

Hormone-refractory prostate cancer (HRPC), which is resistant to hormone therapy, is a major obstacle in clinical treatment. An approach to inhibit HRPC growth and ultimately to kill cancers is highly demanded.

Results

KUD773 induced the anti-proliferative effect and subsequent apoptosis in PC-3 and DU-145 (two HRPC cell lines); whereas, it showed less active in normal prostate cells. Further examination showed that KUD773 inhibited tubulin polymerization and induced an increase of mitotic phosphoproteins and polo-like kinase 1 (PLK1) phosphorylation, indicating a mitotic arrest of the cell cycle through an anti-tubulin action. The kinase assay demonstrated that KUD773 inhibited Aurora A activity. KUD773 induced an increase of Cdk1 phosphorylation at Thr¹⁶¹ (a stimulatory phosphorylation site) and a decrease of phosphorylation at Tyr¹⁵ (an inhibitory phosphorylation site), suggesting the activation of Cdk1. The data were substantiated by an up-regulation of cyclin B1 (a Cdk1 partner). Furthermore, KUD773 induced the phosphorylation and subsequent down-regulation of Bcl-2 and activation of caspase cascades.

Conclusions

The data suggest that KUD773 induces apoptotic signaling in a sequential manner. It inhibits tubulin polymerization associated with an anti-Aurora A activity, leading to Cdk1 activation and mitotic arrest of the cell cycle that in turn induces Bcl-2 degradation and a subsequent caspase activation in HRPCs.     

The molecular diversity of the methanogenic community in a hypereutrophic freshwater lake determined by PCR-RFLP

AIMS: To combine database-held sequence information with a programme of experimental molecular ecology to define the methanogenic community of a hypereutrophic lake by a PCR-restriction fragment length polymorphism (RFLP) analysis. METHODS AND RESULTS: Methanogen diversity in a hypereutrophic freshwater lake was analysed using 16S rDNA PCR-RFLP. Database-held 16S rRNA gene sequences for 76 diverse methanogens were analysed for specific restriction sites that permitted unequivocal differentiation of methanogens. Restriction digestion and agarose gel electrophoresis of the 16S rDNA from selected methanogen pure cultures generated observed restriction profiles that corroborated the expected patterns. This method was then tested by analysing methanogen diversity in samples obtained over 1 year from sediment and water samples taken from the same sampling site. CONCLUSIONS: Restriction analysis of the 16S rRNA gene sequences from 157 methanogen clones generated from lakewater and sediment samples showed that over 50% were similar to Methanoculleus spp. Furthermore, a total of 16 RFLP types (1-16) were identified, eight of which contained no cultured representative archaeal 16S rRNA gene sequences. SIGNIFICANCE AND IMPACT OF THE STUDY: This RFLP strategy provides a robust and reliable means to rapidly identify methanogens in the environment.     

A kinetic model describing Shewanella oneidensis MR-1 growth, substrate consumption, and product secretion

Aerobic growth of Shewanella oneidensis MR-1 in minimal lactate medium was studied in batch cultivation. Acetate production was observed in the middle of the exponential growth phase and was enhanced when the dissolved oxygen (DO) concentration was low. Once the lactate was nearly exhausted, S. oneidensis MR-1 used the acetate produced during growth on lactate with a similar biomass yield as lactate. A two-substrate Monod model, with competitive and uncompetitive substrate inhibition, was devised to describe the dependence of biomass growth on lactate, acetate, and oxygen and the acetate growth inhibition across a broad range of concentrations. The parameters estimated for this model indicate interesting growth kinetics: lactate is converted to acetate stoichiometrically regardless of the DO concentration; cells grow well even at low DO levels, presumably due to a very low K(m) for oxygen; cells metabolize acetate (maximum specific growth rate, micro(max,A) of 0.28 h(-1)) as a single carbon source slower than they metabolize lactate (micro(max,L) of 0.47 h(-1)); and growth on acetate is self-inhibiting at a concentration greater than 10 mM. After estimating model parameters to describe growth and metabolism under six different nutrient conditions, the model was able to successfully estimate growth, oxygen and lactate consumption, and acetate production and consumption under entirely different growth conditions.     

Sodium channel beta1 subunit-mediated modulation of Nav1.2 currents and cell surface density is dependent on interactions with contactin and ankyrin

Voltage-gated sodium channels are composed of a pore-forming alpha subunit and at least one auxiliary beta subunit. Both beta1 and beta2 are cell adhesion molecules that interact homophilically, resulting in ankyrin recruitment. In contrast, beta1, but not beta2, interacts heterophilically with contactin, resulting in increased levels of cell surface sodium channels. We took advantage of these results to investigate the molecular basis of beta1-mediated enhancement of sodium channel cell surface density, including elucidating structure-function relationships for beta1 association with contactin, ankyrin, and Nav1.2. beta1/beta2 subunit chimeras were used to assign putative sites of contactin interaction to two regions of the beta1 Ig loop. Recent studies have shown that glutathione S-transferase fusion proteins containing portions of Nav1.2 intracellular domains interact directly with ankyrinG. We show that native Nav1.2 associates with ankyrinG in cells in the absence of beta subunits and that this interaction is enhanced in the presence of beta1 but not beta1Y181E, a mutant that does not interact with ankyrinG. beta1Y181E does not modulate Nav1.2 channel function despite efficient association with Nav1.2 and contactin. beta1Y181E increases Nav1.2 cell surface expression, but not as efficiently as wild type beta1. beta1/beta2 chimeras exchanging various regions of the beta1 Ig loop were all ineffective in increasing Nav1.2 cell surface density. Our results demonstrate that full-length beta1 is required for channel modulation and enhancement of sodium channel cell surface expression.     

Estimating fossil biomass from skeletal mass in marine invertebrates

Palaeoecology uses the numerical abundance and the occurrence of species to evaluate the dynamics of past communities, but biomass – the quantity of soft tissue – is the critical currency needed to capture the flow and role of nutrients in modern ecosystems. Acquiring biomass data from fossil assemblages has, however, remained challenging, thus limiting the analysis of net secondary production in palaeocommunities. Prior models relate shell size or shell biovolume to fossil biomass. These models neglect shell fragments and, moreover, use units of biovolume (cm³) that are not directly related to those of biomass (g), making the models difficult to tune and the coefficients highly specific. To remedy these shortcomings, I evaluate skeletal mass as a means of estimating the soft tissue biomass of fossil taxa, using ratios among biomass, skeletal mass and the total wet mass of living representatives of extant species, so that skeletal mass alone can be used to estimate grams of organic biomass. Data on total wet mass, organic carbon mass, and shell mass were acquired from more than 80 live‐collected individuals from eight families in three major, shelly macrobenthic groups (Mollusca, Brachiopoda, Arthropoda) and supplemented with counterpart data from the literature to increase taxonomic breadth. This new shell‐mass model provides more accurate and precise biomass estimates than models based on the linear dimensions of shells, expanding our ability to examine the interplay between organisms and their environments.     

Culture of bovine embryos after invitro exposure to Brucellaabortus

Fifty-four day-6 through day-10 (estrus=day 0) embryos were collected nonsurgically from 13 superovulated, brucellosis-free mixed breed cows. Forty-eight excellent and good zona pellucida-intact (ZP-I), three zona pellucida-defective (ZP-D), and three zona pellucida-free (ZP-F) embryos were incubated in media containing $\text{Brucella}$$\text{abortus}$. Subsequently, embryos were washed ten times in groups of one, two, three, or four. Embryos and serial washes were cultured for $\text{B}$. $\text{abortus}$.Brucellae were not isolated from any ZP-I embryo or from any washing beyond the sixth serial wash. Brucellae were not isolated from the three ZP-F embryos but were detected in the eighth wash for one and in the tenth wash for the others. Brucellae were isolated from one of three ZP-D embryos. Results show that ZP-I embryos can be effectively washed free of $\text{B}$. $\text{abortus}$.     

Early Tertiary fossil plants and paleoclimate of Lanzhou Basin

Fossil plants from the lower part of Xianshuihe Formation in the Lanzhou Basin, Gansu Province were studied. The flora contains 29 species, representing 20 genera and 12 families, which include Lauraceae ( Daphnogene ), Lardizabalaceae ( Akebia ), Berberidaceae ( Berberis ), Ulmaceae ( Planera, Ulmus, Zelkova ), Betulaceae ( Alnus, Carpinus ), Myricaceae( Myrica ), Salicaceae ( Populus, Salix), Myrsinaceae(Ardisia), Rosaceae ( Prunus, Sorbus, Sorbaria, Spiraea ), Leguminosae ( Gleditsia, Sophora), Anacardiaceae (Rhus), Caprifoliaceae(Viburnum). An analysis of the floristic elements and their foliar physiognomy shows that most members of the flora are deciduous broad-leaved trees or shrubs with a few evergreen shrubs. The most noteworthy species is Rhus turcomanica which was present in the Middle Eocene to Late Eocene of Central Asia (Kazakhstan, Turkmenistan). Generally, Rhus turcomanica occurred at the same beds as Palibinia, an extinct fossil plant whose presence indicates a subtropical dry climate. Another species, Sorbaria callicomifolia Kornilova was present from the Early Oligocene to Early Miocene of Central Asia (Kazakhstan and Turkmenistan). According to an analysis of spores and pollen, this flora contains over 20 species. It is predominated by the angiosperm pollen. There appeared Ephedripites and Nitrariadites which were important elements in the dry area. Ephedripites was found from the Upper Cretaceous to Early Tertiary. Nitrariadites occurred in the Late Miocene, whereas Rhus turcomanica and Sorbaria callicomifolia were both reported in the subtropical dry area from the Middle Eocene to Early Oligocene. The latest record of Rhus turcomanica is from the Middle Eocene to Early Oligocene of Central Asia. The presence of this element in the lower part of Xianshuihe Formation may indicate that itsage is the latest stage of the Early Oligocene.