Effect of magnetic field on activity of cytochrome oxidase not moved or moved relative to magnetic field lines

The influence of constant homogeneous magnetic fields (700 to 13,000 gauss) on cytochrome c oxidase activity as a function of strength and duration of magnetic field and as a function of enzyme concentration at 0-5 degrees C in solution was measured on samples not moved or moved relative to the magnetic field lines. Increases or decreases of enzyme activity were observed depending on whether or not the samples were so moved. These changes persisted for hours after terminating exposure to the magnetic field.     

Dynamical correlation of non-stationary signals in time domain—A comparative study

In a thorough study, the multitaper (MTM) and the extended continuous wavelet-transform (CWT) coherence-analysis methods were compared in terms of there application in determining the dynamics from the electroencephalogram (EEG) and electromyogram (EMG) signals of patients with Parkinsonian tremor. The main aim of the study in a biological point of view is to analyze whether the basic tremor frequency and its “first harmonic” frequency of Parkinsonian tremor are really harmonically related or are in fact distinct processes.The extension of the CWT is achieved by using a Morlet wavelet as the analysis window with an adjustable relative bandwidth which gives the flexibility in setting a desired frequency resolution. In order to obtain a perspective view of the two methods, they were applied to two different model signals to determine their actual threshold in detecting short-lived changes in the analysis of non-stationary signals and to determine their noise thresholds by adding external noise to the signals to test the reduction in coherence to be not merely due to the random fluctuations in stochastic signals. Beyond applying an autoregressive 2nd-order and a coupled van der Pol model system, however, also true EEG and EMG data from five Parkinson patients were used. The results were compared in terms of the time and frequency resolutions of these two methods, and it was determined that the multitaper method was able to detect reduction in power and coherence as short as 1 s. The extended CWT analysis only revealed gaps that were longer than 3 s.The time gaps in the coherence indicate the loss of connection between the cortex and muscle during the respective time intervals. This more accurate analysis of the MTM was also seen in the dynamical EEG–EMG coherence at the tremor frequency and its “first harmonic” of Parkinsonian patients.In terms of our “biological” aim, this shows distinct prevalence of the corticomuscular coupling at those frequencies over time. Applying this method to biological data reveals important aspects about their dynamics, e.g., the distinct dynamics between basic frequency and “first harmonic” frequency over time in Parkinsonian tremor.     

First report of an intraerythrocytic small piroplasm in wild Iberian lynx (Lynx pardinus)

A wild injured Iberian lynx (Lynx pardinus) was taken from the Sierra Morena population. During the health check small intraerythrocytic piroplasms, morphologically indistinguishable from other feline piroplasms, were observed in Wright-Giemsa-stained blood films. Amplification by polymerase chain reaction of a portion of the 18S nuclear small subunit (NSS) rRNA gene and sequencing revealed similarity of the unknown organism with sequences obtained from Pallas's cat from Mongolia and from a domestic cat in Spain. In a retrospective (1993-2003) study of 50 Iberian lynx tissue samples, no amplifications of the 18S NSS rRNA gene of the organism were obtained. This is the first report of a naturally occurring erythroparasitemia in the Iberian lynx and the first documented case of naturally occurring piroplasm infection in a free-ranging felid from Europe.     

Synthesis and structural characterisation of metallated aminomethylanilines

Reaction of [1-{Me₃SiNH}-2-{Me₃SiNHCH₂}]C₆H₄ (1) and [1-{tBuMe₂SiNH}-2-{tBuMe₂SiNHCH₂}]C₆H₄ (2) in tetrahydrofuran with two equivalents of n-butyllithium gave the lithium amides [1-{Me₃SiN(Li)}-2-{Me₃SiN(Li)CH₂}]C₆H₄(thf)₃ (3) and [1-{tBuMe₂SiN(Li)}-2-{tBuMe₂SiN(Li)CH₂}]C₆H₄(thf)₂ (4). The molecular structures of both 3 and 4, which were established by X-ray diffraction studies, differ in the number of thf molecules coordinated to the Li centres. Depending on the size of the amidomethyl-bonded silyl groups two (4) or three thf-coligands (3) were found to bind to the lithium centres rendering them tri- or tetracoordinate, respectively. In the Me₃Si-substituted derivative 3 a rare example of a thf molecule as a bridging ligand was found which appears to pertain as such in solution. The reaction of the lithium amides 3 and 4 with two molar equivalents of TlCl in n-pentane gave the thallium(I) amides [1-{Me₃SiN(Tl)}-2-{Me₃SiN(Tl)CH₂}]C₆H₄ (5) and [1-{tBuMe₂SiN(Tl)}-2-{tBuMe₂SiN(Tl)CH₂}]C₆H₄ (6) which are stable in hydrocarbon solutions but rapidly decompose in polar solvents.     

Functional Analyses of the Plant Photosystem I-Light-Harvesting Complex II Supercomplex Reveal That Light-Harvesting Complex II Loosely Bound to Photosystem II Is a Very Efficient Antenna for Photosystem I in State II

State transitions are an important photosynthetic short-term response that allows energy distribution balancing between photosystems I (PSI) and II (PSII). In plants when PSII is preferentially excited compared with PSI (State II), part of the major light-harvesting complex LHCII migrates to PSI to form a PSI-LHCII supercomplex. So far, little is known about this complex, mainly due to purification problems. Here, a stable PSI-LHCII supercomplex is purified from Arabidopsis thaliana and maize (Zea mays) plants. It is demonstrated that LHCIIs loosely bound to PSII in State I are the trimers mainly involved in state transitions and become strongly bound to PSI in State II. Specific Lhcb1-3 isoforms are differently represented in the mobile LHCII compared with S and M trimers. Fluorescence analyses indicate that excitation energy migration from mobile LHCII to PSI is rapid and efficient, and the quantum yield of photochemical conversion of PSI-LHCII is substantially unaffected with respect to PSI, despite a sizable increase of the antenna size. An updated PSI-LHCII structural model suggests that the low-energy chlorophylls 611 and 612 in LHCII interact with the chlorophyll 11145 at the interface of PSI. In contrast with the common opinion, we suggest that the mobile pool of LHCII may be considered an intimate part of the PSI antenna system that is displaced to PSII in State I.     

Usnic acid,as a biotic factor,changes the ploidy level in mosses

Lichens and mosses often share the same environmental conditions where they compete for substrate and other essential factors. Lichens use secondary metabolites as allelochemicals to repel surrounding plants and potential rivals. In mosses, endoreduplication leads to the occurrence of various ploidy levels in the same individual and has been suggested as an adaptation to abiotic stresses. Here, we show that also biotic factors such as usnic acid, an allelochemical produced by lichens, directly influenced the level of ploidy in mosses. Application of usnic acid changed the nuclei proportion and significantly enhanced the endoreduplication index in two moss species, Physcomitrella patens and Pohlia drummondii. These investigations add a new aspect on secondary metabolites of lichens which count as biotic factors and affect ploidy levels in mosses.     

Synthesis of alpha-substituted fosmidomycin analogues as highly potent Plasmodium falciparum growth inhibitors

In view of the promising antimalarial activity of fosmidomycin or its N-acetyl homologue FR900098, the objective of this work was to investigate the influence of aromatic substituents in the alpha-position of the phosphonate moiety. The envisaged analogues were prepared using a linear route involving a 3-aryl-3-phosphoryl propanal intermediate. The activities of all compounds were evaluated on Eschericia coli 1-deoxy-d-xylulose 5-phosphate reductoisomerase and against two Plasmodium falciparum strains. Compared with fosmidomycin, several analogues displayed enhanced activity towards the P. falciparum strains. Compound 1e with a 3,4-dichlorophenyl substitution in the alpha-position of fosmidomycin emerged as the most potent analogue of this series. It is approximately three times more potent in inhibiting the growth of P. falciparum than FR900098, the most potent representative of this class reported so far.     

Acyloxyalkyl ester prodrugs of FR900098 with improved in vivo anti-malarial activity

FR900098 represents an improved derivative of the new antimalarial drug fosmidomycin and acts through inhibition of the 1-deoxy-D-xylulose 5-phosphate (DOXP) reductoisomerase, an essential enzyme of the mevalonate independent pathway of isoprenoid biosynthesis. Prodrugs with increased activity after oral administration were obtained by chemical modification of the phosphonate moiety to yield acyloxyalkyl esters. The most successful compound demonstrated 2-fold increased activity in mice infected with the rodent malaria parasite Plasmodium vinckei.     

Effect of magnetic field on the process of cell respiration in mitochondria of rats

Exposure of rats to static magnetic field 1 hour daily for a period of 7 weeks (7 days a week) leading to disturbances of the respiration processes in the mitochondria of liver cells. The rate of respiration through NADH dehydrogenase, succinic dehydrogenase and cytochrome oxidase was dependent on both the duration and the intensity value of the field applied. The animals showed greater sensitivity to the action of a 0.008 T magnetic induction field than to that of 0.15 T. The observed changes were reversible after 3 months since the everyday exposure had been stopped.