Ventilatory mechanics from maniraptoran theropods to extant birds

Shared behavioural, morphological and physiological characteristics are indicative of the evolution of extant birds from nonavian maniraptoran dinosaurs. One such shared character is the presence of uncinate processes and respiratory structures in extant birds. Recent research has suggested a respiratory role for these processes found in oviraptorid and dromaeosaurid dinosaurs. By measuring the geometry of fossil rib cage morphology, we demonstrate that the mechanical advantage, conferred by uncinate processes, for movements of the ribs in the oviraptorid theropod dinosaur, Citipati osmolskae, basal avialan species Zhongjianornis yangi, Confuciusornis sanctus and the more derived ornithurine Yixianornis grabaui, is of the same magnitude as found in extant birds. These skeletal characteristics provide further evidence of a flow-through respiratory system in nonavian theropod dinosaurs and basal avialans, and indicate that uncinate processes are a key adaptation facilitating the ventilation of a lung air sac system that diverged earlier than extant birds.     

Circadian clock genes cause activation of the human PAI-1 gene promoter with 4G/5G allelic preference

Increased plasminogen activator inhibitor-1 (PAI-1) activity is associated with greater risk of myocardial infarction. PAI-1 expression is regulated by a 4G/5G promoter polymorphism. The 4G allele is associated with higher PAI-levels and greater circadian variation. Here we show that clock protein heterodimers BMAL/CLOCK cause greater activation (approximately 2-fold, P<0.05) of the 4G allele. Site-directed mutagenesis studies suggest that clock genes act on two canonical E-boxes to regulate PAI-1 promoter activity. These results identify a potential novel mechanism whereby allele-specific clock genes - mediated modulation of PAI-1 expression may contribute to circadian variation in cardiac risk.     

Optimization of anabaenopeptin extraction from cyanobacteria and the effect of methanol on laboratory manipulation

Anabaenopeptins are commonly occurring bioactive peptides of cyanobacterial origin. Cyanobacteria (blue-green algae) are known to be capable of producing a large number of biologically active peptides, but the widespread occurrence of anabaenopeptins in particular, makes them ideal candidates for investigating the reasons that cyanobacteria produce such a complex spectrum of peptides and the wider implications of their natural function(s). Despite the identification of these peptides in cyanobacterial samples, little is known about the concentrations produced. For this reason, methods for the quantitative extraction of anabaenopeptins from lyophilized cyanobacterial cells were optimized. Higher yields of anabaenopeptins were obtained using aqueous methanol extraction than using water alone. However, repeat extractions using 50, 70 or 90% aqueous methanol did not result in significantly different total yields of the anabaenopeptin variants, ABPN-A and -B. Similarly, little difference was found in the quantification of purified ABPN-A and -B by high performance liquid chromatography with photodiode array detection (HPLC-PDA) when analyzed in methanol solutions of different concentrations. The effects of solvent concentration on the laboratory handling of ABPN-A and -B in glass and plastic containers were also investigated. Significantly lower concentrations of dissolved ABPN-A and -B were found when aqueous solutions came into contact with plastics, but not 50 or 100% methanol.     

Strong effects of amoebae grazing on the biomass and genetic structure of a Microcystis bloom (Cyanobacteria)

Despite its importance for bloom toxicity, the factors determining the population structure of cyanobacterial blooms are poorly understood. Here, we report the results of a two‐year field survey of the population dynamics of Microcystis blooms in a small hypertrophic urban pond. Microscopic enumeration of Microcystis and its predators and parasites was combined with pigment and microcystin analysis and denaturing gradient gel electrophoresis of the ITS rDNA region to assess population dynamics and structure. Two main Microcystis morpho‐ and ITS types were revealed, corresponding to M. aeruginosa and M. viridis. In both years, high population densities of naked amoebae grazing on Microcystis coincided with rapid decreases in Microcystis biomass. In one year, there was a shift from heavily infested M. aeruginosa to the less‐infested M. viridis, allowing the bloom to rapidly recover. The preference of amoebae for M. aeruginosa was confirmed by grazing experiments, in which several amoeba strains were capable of grazing down a strain of M. aeruginosa, but not of M. viridis. Zooplankton and chytrid parasites appeared to be of minor importance for these strong and fast reductions in Microcystis biomass. These findings demonstrate a strong impact of small protozoan grazers on the biomass and genetic structure of Microcystis blooms.     

LOCALIZATION OF MICROCYSTIN SYNTHETASE GENES IN COLONIES OF THE CYANOBACTERIUM MICROCYSTIS USING FLUORESCENCE IN SITU HYBRIDIZATION1

To better understand the production of microcystins (MCs) in Microcystis colonies, fluorescence in situ hybridization (FISH) methods were developed to detect DNA involved in the synthesis of these cyanobacterial hepatotoxins. Using colonies of Microcystis aeruginosa (Kütz.) Kütz. isolated from environmental blooms of cyanobacteria and from a colony‐forming, MC‐producing laboratory strain of Microcystis, amplified PCR products were observed, coincident with positive controls. The total MC content of individual colonies of Microcystis, determined by ELISA, showed a positive correlation with colony cross‐sectional area. FISH analysis of Microcystis colonies gave high fluorescence in comparison to negative controls, indicating the presence of MC synthetase DNA (mcyA) in situ. FISH analysis for MC synthetase genes has the potential to be developed into an effective early warning tool for drinking and recreational water management.     

The occurrence, distribution and toxicity of cyanobacteria in the estuary of Lagoa dos Patos, Rio Grande do Sul

Several blooms of Microcystis aeruginosa have been observed in the Patos Lagoon estuary during the last fifteen years without a proper investigation of their ecological importance or possible toxicity. The present study has identified and quantified the presence of cyanobacteria in the Patos Lagoon estuary, particularly of M. aeruginosa. During this survey, identification and quantification of the main phytoplankton groups were done in relation to geographical distribution in the estuary. The presence of M. aeruginosa colonies in the estuarine region confirmed their superficial distribution throughout the estuarine waters during twelve months with a maximum of 1, 3.10(6) cells. L-1 in December, 1994 and a minimum of 1, 5.10(5) cells. L-1 in August, 1995 and also confirmed that M. aeruginosa originated from waters in the north of the estuary. The period of the highest cell and colonies densities was coincident with high chlorophyll-a levels in surface waters. Toxicity of M. aeruginosa bloom material was determined by bioassay and concentrations of hepatotoxins microcystins were identified by HPLC-DAD. M. aeruginosa blooms were considered highly toxic, presenting a 24 h-LD50 lower than 100 mg.Kg-1 b.w. and a toxin content higher than 1 microgram.mg-1 d.w. Several microcystin variants were found in the extracts with microcystin-LR predominating.     

Synthesis and structure--activity relationships of aroylpyrrole alkylamide bradykinin (B2) antagonists

The synthesis and structure-activity relationships of a novel series of aroylpyrrole alkylamides as potent selective bradykinin B(2) receptor antagonists are described. Several members of this series display nanomolar affinity at the B(2) receptor and show activity in an animal model of antinociception.     

Prognostic biomarkers for survival in mucosal melanoma

Mucosal melanoma (MM) is a rare subtype of melanoma with an aggressive clinical course. In cutaneous melanoma (CM), the absence of pigmentation and presence of NRAS/KRAS mutations are biomarkers indicating an aggressive clinical course with shorter overall survival. Similar data for MM are missing. We present the real-world outcome data in a cohort of genotyped MM patients and assessed the prognostic relevance of pigmentation- and NRAS/KRAS mutation status. We correlated pathological reports and clinical data with overall survival of patients with MM. Furthermore, we performed clinically integrated molecular genotyping and analyzed real world treatment regimens for covariates associated with clinical outcome. We identified 39 patients with available clinical and molecular data. Patients with amelanotic MM had a significantly shorter overall survival (p = .003). In addition, the presence of a NRAS or KRAS mutation was significantly associated with poor overall survival (NRAS or KRAS p = .024). Currently, it is unknown if the same prognostic relevance for the lack of pigmentation and RAS mutations in CM, exists in MM. Here we analyzed a cohort of MM for outcome measures and determined that two known prognostic biomarkers for CM are in fact novel prognosticators for MM.     

The site of inhibition of photosystem II by 3-(3,4-dichlorophenyl)-N-N'-dimethylurea in thylakoids of the cyanobacterium Anabaena cylindrica.

Thylakoids isolated from the cyanobacterium $\text{Anabaena}\text{cylindrica}$ exhibit Photosystem II activity. Photosynthetic electron transfer from water to ferricyanide and to 2,6-dichlorophenolindophenol is inhibited by 3-(3,4-dichlorophenyl)-N-N′-dimethyl urea. Diphenylcarbazide stimulates ferricyanide and 2,6-dichlorphenolindophenol photoreduction, whilst inhibiting oxygen evolution. Diphenylcarbazide-supported Photosystem II activity is completely insensitive to 3-(3,4-dichlorophenyl)-N-N′-dimethyl urea, indicating that the site of action of this inhibitor lies on the donor side of Photosystem II in $\text{A}\text{.}\text{cylindrica}$, before the site of electron donation by diphenylcarbazide.