Effects of weak magnetic fields on the production of reactive oxygen species in peritoneal neutrophils in mice

The influence of weak magnetic fields of different types on the rate of the formation of reactive oxygen species in mouse peritoneal neutrophils has been studied. It was found that the exposure of neutrophils activated by phorbol 12-myristate 13-acetate to the magnetic field tuned to the parametric resonance for Ca2+ ions leads to a decrease in the rate of the reactive oxygen species (ROS) generation by 23%. Conversely, the generation of ROS in neutrophils exposed to the same field but stimulated by the bacterial peptide FMLP (N-formyl-L-methionyl-L-leucyl-L-phenylalanine) increased by about 21%. Pulsed magnetic fields also changed the rate of ROS generation in phorbol-stimulated neutrophils by about 20%, but the sign of the effects observed in this case was opposite to those induced by the magnetic field tuned to the parametric resonance for Ca2+ ions.     

Dephosphorylation of AMP-activated protein kinase in a postural muscle: A key signaling event on the first day of functional unloading

Biophysics - The AMP analog 5-aminoimidazole-4-carboxamide ribofuranoside (AICAR), which acts as an AMP-activated protein kinase (AMPK) activator, was used to study the signal effects of AMPK...     

Monthly day/night changes and seasonal daily rhythms of sexual steroids in Senegal sole (Solea senegalensis) under natural fluctuating or controlled environmental conditions

In this paper we attempted to investigate the existence of daily fluctuations on plasma sexual steroids (17beta-estradiol, E(2) and testosterone, T) in Senegal sole (Solea senegalensis) females. We described the monthly day/night concentrations and seasonal daily rhythms in animals reared under natural photo- and thermo-period. In addition, the influence of the natural annual fluctuation of the water temperature on the plasma concentration of these steroids was investigated, using one group of Senegal sole under a natural photoperiod, but with an attenuated thermal cycle (around 17-20 degrees C) for one year. Although no significant day/night differences were detected in monthly samplings, the existence of an annual rhythm of E(2) and T (p<0.01) with an acrophase in February was revealed by COSINOR analysis. Maximum values were reached in March for both steroids (6.1+/-1.7 ng mL(-1) at mid-dark, MD and 4.0+/-0.6 ng mL(-1) at mid-light, ML for E2 and 1.4+/-0.4 ng mL(-1) at MD and 0.8+/-0.1 ng mL(-1) at ML for T) in anticipation of the spawning season (May-June). As regards seasonal daily rhythms, the presence of daily oscillations was revealed. At the spring solstice (21st March) a daily rhythm was observed for both steroids (COSINOR, p<0.01), with an acrophase at 20:00 h (E(2)) and at 21:08 h (T). In summer, autumn and winter no daily rhythms were observed due to the low steroid levels at those seasons. When Senegal sole females were submitted to an attenuated annual thermal cycle, the steroid rhythm disappeared (there was no surge in spring, as in the control group) and these fish did not spawn, despite being subjected to natural photoperiod conditions. This result underlined the importance of the natural annual fluctuation of water temperature and photoperiod on the synchronization of the spawning season and on the onset of steroidogenesis.     

Modulation of cardiac rhythm in the humans exposed to extremely weak alternating magnetic fields

The effect of extremely weak alternating magnetic fields of various types with the amplitudes δ of 2 μT on the heart rate variability in humans was studied. Volunteers were placed in a large-volume coil system (2ω2ω2 m), which provided exposure of the whole body to extremely weak alternating magnetic fields uniform in their amplitude. It was shown for the first time that the exposure to such fields could both increase and decrease the magnitude of stress in humans. In particular, the field tuned to the nuclear spins of hydrogen atoms (amplitude, 1.6 μT and frequency, 76 Hz) decreased the Baevsky stress index, whereas the field tuned to the magnetic moments formed by the orbiting electrons in some atoms (amplitude, 0.192 μT and frequency, 3000 Hz) increased this index. These results provide a possible explanation for the mechanisms of adverse effects caused by extremely weak alternating magnetic fields of certain types of both technogenic and natural origins on the human cardiovascular system.     

Molecular characterisation of the caprine (<Emphasis Type="Italic">Capra hircus</Emphasis>) lymphocyte function-associated antigen-1 alpha subunit-encoding cDNA

Background

Lymphocyte function-associated antigen-1 (LFA-1, CD11a/CD18, alpha L beta 2) is required for many cellular adhesive interactions during the immune response.

Results

The Capra hircus CD11a-encoding cDNA was sequenced and compared with its human, murine, rat, bovine and ovine counterparts. Despite some focal differences, it shares all the main characteristics of its known mammalian homologues.

Conclusion

Therefore, along with the caprine CD18-encoding cDNA, which has been available for a few months, the sequence data revealed here will allow the Capra hircus LFA-1 expression in vitro as a tool to explore the specificities of inflammation in the caprine species.

     

The nucleotide sequence of the gene coding for the 16S rRNA from the archaebacterium Halobacterium halobium

The complete 1473-bp sequence of the 16S rRNA gene from the archaebacterium Halobacterium halobium has been determined. Alignment with the sequences of the 16S rRNA gene from the archaebacteria Halobacterium volcanii and Halococcus morrhua reveals similar degrees of homology, about 88%. Differences in the primary structures of H. halobium and eubacterial (Escherichia coli) 16S rRNA or eukaryotic (Dictyostelium discoideum) 18S rRNA are much higher, corresponding to 63% and 56% homology, respectively. A comparison of the nucleotide sequence of the H. halobium 16S rRNA with those of its archaebacterial counterparts generally confirms a secondary structure model of the RNA contained in the small subunit of the archaebacterial ribosome.     

The movement protein of cucumber mosaic virus traffics into sieve elements in minor veins of nicotiana clevelandii

The location of the 3a movement protein (MP) of cucumber mosaic virus (CMV) was studied by quantitative immunogold labeling of the wild-type 3a MP in leaves of Nicotiana clevelandii infected by CMV as well as by using a 3a-green fluorescent protein (GFP) fusion expressed from a potato virus X (PVX) vector. Whether expressed from CMV or PVX, the 3a MP targeted plasmodesmata and accumulated in the central cavity of the pore. Within minor veins, the most extensively labeled plasmodesmata were those connecting sieve elements and companion cells. In addition to targeting plasmodesmata, the 3a MP accumulated in the parietal layer of mature sieve elements. Confocal imaging of cells expressing the 3a-GFP fusion protein showed that the 3a MP assembled into elaborate fibrillar formations in the sieve element parietal layer. The ability of 3a-GFP, expressed from PVX rather than CMV, to enter sieve elements demonstrates that neither the CMV RNA nor the CMV coat protein is required for trafficking of the 3a MP into sieve elements. CMV virions were not detected in plasmodesmata from CMV-infected tissue, although large CMV aggregates were often found in the parietal layer of sieve elements and were usually surrounded by 3a MP. These data suggest that CMV traffics into minor vein sieve elements as a ribonucleoprotein complex that contains the viral RNA, coat protein, and 3a MP, with subsequent viral assembly occurring in the sieve element parietal layer.