Long, saturated chains: tasty domains for kinases of insulin resistance

The mechanistic basis of how cells respond to increased fatty acids (FAs) is murky but potentially involves receptor-mediated activation or inhibition by different FA classes. Holzer et?al. (2011) recently propose in Cell that expansion of intracellular membrane microdomains induced by saturated FA recruit and activate c-Src for JNK activation.     

Identification of benzo[c]phenanthridine metabolites in human hepatocytes by liquid chromatography with electrospray ion-trap and quadrupole time-of-flight mass spectrometry

The metabolism of the benzo[c]phenanthridine alkaloids was studied using human hepatocytes which are an excellent model system for biotransformation studies. For analysis of the alkaloids and their metabolites, an electrospray quadrupole ion-trap mass spectrometry (ESI ion-trap MS) connected to a reversed phase chromatographic system based on cyanopropyl modified silica was used. The optimized experimental protocol allowed simultaneous analysis of the alkaloids and their metabolites and enabled study of their uptake into and interconversion in human hepatocytes. The results show that formation of the dihydro metabolite which may be followed by specific O-demethylenation/O-demethylation processes, is probably the main route of biotransformation (detoxification) of the benzo[c]phenanthridines in human hepatocytes. The structure of the main O-demethyl metabolite (2-methoxy-12-methyl-12,13-dihydro-[1,3]dioxolo[4',5':4,5]benzo[1,2-c]phenanthridin-1-ol; 336.1 m/z,) was proposed by the multi-stage MS and quadrupole time-of-flight MS methods using chemically synthesized standard.     

Erratum to: Long-range corrected DFT calculations of charge-transfer integrals in model metal-free phthalocyanine complexes

Journal of Molecular Modeling -     

Directional preference may enhance hunting accuracy in foraging foxes

Red foxes hunting small animals show a specific behaviour known as 'mousing'. The fox jumps high, so that it surprises its prey from above. Hearing seems to be the primary sense for precise prey location in high vegetation or under snow where it cannot be detected with visual cues. A fox preparing for the jump displays a high degree of auditory attention. Foxes on the prowl tend to direct their jumps in a roughly north-eastern compass direction. When foxes are hunting in high vegetation and under snow cover, successful attacks are tightly clustered to the north, while attacks in other directions are largely unsuccessful. The direction of attacks was independent of time of day, season of the year, cloud cover and wind direction. We suggest that this directional preference represents a case of magnetic alignment and enhances the precision of hunting attacks.     

Alien plants introduced by different pathways differ in invasion success: unintentional introductions as a threat to natural areas

Background

Understanding the dimensions of pathways of introduction of alien plants is important for regulating species invasions, but how particular pathways differ in terms of post-invasion success of species they deliver has never been rigorously tested. We asked whether invasion status, distribution and habitat range of 1,007 alien plant species introduced after 1500 A.D. to the Czech Republic differ among four basic pathways of introduction recognized for plants.

Principal Findings

Pathways introducing alien species deliberately as commodities (direct release into the wild; escape from cultivation) result in easier naturalization and invasion than pathways of unintentional introduction (contaminant of a commodity; stowaway arriving without association with it). The proportion of naturalized and invasive species among all introductions delivered by a particular pathway decreases with a decreasing level of direct assistance from humans associated with that pathway, from release and escape to contaminant and stowaway. However, those species that are introduced via unintentional pathways and become invasive are as widely distributed as deliberately introduced species, and those introduced as contaminants invade an even wider range of seminatural habitats.

Conclusions

Pathways associated with deliberate species introductions with commodities and pathways whereby species are unintentionally introduced are contrasting modes of introductions in terms of invasion success. However, various measures of the outcome of the invasion process, in terms of species'' invasion success, need to be considered to accurately evaluate the role of and threat imposed by individual pathways. By employing various measures we show that invasions by unintentionally introduced plant species need to be considered by management as seriously as those introduced by horticulture, because they invade a wide range of seminatural habitats, hence representing even a greater threat to natural areas.     

10. Na Bahně (Czech Republic): Vegetation development over the last 2.5 millennia in the Eastern Bohemian lowland

To determine the best date for patients in the southern part of the Netherlands to begin treatment for pollinosis, an attempt was made to predict the start of the grass pollen season at Helmond as accurately as possible, as was previously done at Leiden. The start of the grass pollen season was defined as the date when at a given location the accumulated total (from 1 Jan.) of 24 h average grass pollen concentrations (No./m³) reaches 100 (the so-called Σ100-method). Using the phenological method over the years 1981 through 1985, with the birch (Σ125=x) as the indicator plant, the start of the grass pollen period (Σ100=z) could be predicted much more accurately than would have been possible solely on the basis of the mean starting dates in the preceding years. The predicted starting date (z) can be calculated with the equation z=0.44x+95.46 (x and z as day-of-year numbers), SD=3.6 days, r=0.83, n=5). The SD of the Σ100-method of grasses being 5.6 days, the effectivity of the prediction is 35.7%. The difference in results between Helmond and Leiden is discussed.     

63 EMSA detection of p53 sequence non-specific binding in PCR produced human DNA analogues

p53 is a tumor suppressor that induces cell cycle arrest and apoptosis in response to DNA damage and cancerogenesis. Its ability to bind DNA, and thus play its biological role, is possible in two manners: sequence-specific binding to its consensus sequence (p53CON) and sequence non-specific binding, which occurs preferably in higher DNA structures. Recently, it has been proven that DNA quadruplexes occur in regulation areas of most cancer genes. In our study, we have tested human DNA cloned into plasmid vectors. The DNAs were obtained by chromatin immunoprecipitation of regions which were bound by p53 with high affinity, although they do not contain p53CON. The sequence studied in this work is located in a noncoding region of human chromosome 7. We suggest that structure-specific binding is responsible for higher affinity of p53 binding in these areas. It has been previously found that some single-stranded regions appeared in these areas, suggesting the presence of higher DNA structures by S1 nuclease digestion (unpublished results). Because we were unable to detect the exact location of p53 binding with sufficient resolution by standard methods, we have amplified different parts of immunoprecipitated DNAs by PCR and found, using EMSA, to what part of the insert p53 binds with the highest affinity. This area is represented by cca 150 nucleotides. The strongest preference of p53 was found for the region which contained repeated short tracts of 3–4 Ts and a short polyPu.polyPy sequence. It is known that dAn:dTn blocks can cause DNA curvature, and the polyPu.polyPy sequence is able to form an intramolecular triplex.