Effects of Exogenous Galanin on Neuropathic Pain State and Change of Galanin and Its Receptors in DRG and SDH after Sciatic Nerve-Pinch Injury in Rat

A large number of neuroanatomical, neurophysiologic, and neurochemical mechanisms are thought to contribute to the development and maintenance of neuropathic pain. However, mechanisms responsible for neuropathic pain have not been completely delineated. It has been demonstrated that neuropeptide galanin (Gal) is upregulated after injury in the dorsal root ganglion (DRG) and spinal dorsal horn (SDH) where it plays a predominantly antinociceptive role. In the present study, sciatic nerve-pinch injury rat model was used to determine the effects of exogenous Gal on the expression of the Gal and its receptors (GalR1, GalR2) in DRG and SDH, the alterations of pain behavior, nerve conduction velocity (NCV) and morphology of sciatic nerve. The results showed that exogenous Gal had antinociceptive effects in this nerve-pinch injury induced neuropathic pain animal model. It is very interesting that Gal, GalR1 and GalR2 change their expression greatly in DRG and SDH after nerve injury and intrathecal injection of exougenous Gal. Morphological investigation displays a serious damage after nerve-pinch injury and an amendatory regeneration after exogenous Gal treatment. These findings imply that Gal, via activation of GalR1 and/or GalR2, may have neuroprotective effects in reducing neuropathic pain behaviors and improving nerve regeneration after nerve injury

An aluminum shield enables the amphipod Hirondellea gigas to inhabit deep-sea environments.

The amphipod Hirondellea gigas inhabits the deepest regions of the oceans in extreme high-pressure conditions. However, the mechanisms by which this amphipod adapts to its high-pressure environment remain unknown. In this study, we investigated the elemental content of the exoskeleton of H. gigas specimens captured from the deepest points of the Mariana Trench. The H. gigas exoskeleton contained aluminum, as well as a major amount of calcium carbonate. Unlike other (accumulated) metals, aluminum was distributed on the surface of the exoskeleton. To investigate how H. gigas obtains aluminum, we conducted a metabolome analysis and found that gluconic acid/gluconolactone was capable of extracting metals from the sediment under the habitat conditions of H. gigas. The extracted aluminum ions are transformed into the gel state of aluminum hydroxide in alkaline seawater, and this gel covers the body to protect the amphipod. This aluminum gel is a good material for adaptation to such high-pressure environments

Isolation and cultivation of a novel sulfate-reducing magnetotactic bacterium belonging to the genus Desulfovibrio.

Magnetotactic bacteria (MTB) synthesize magnetosomes composed of membrane-enveloped magnetite (Fe3O4) and/or greigite (Fe3S4) nanoparticles in the cells. It is known that the magnetotactic Deltaproteobacteria are ubiquitous and inhabit worldwide in the sediments of freshwater and marine environments. Mostly known MTB belonging to the Deltaproteobacteria are dissimilatory sulfate-reducing bacteria that biomineralize bullet-shaped magnetite nanoparticles, but only a few axenic cultures have been obtained so far. Here, we report the isolation, cultivation and characterization of a dissimilatory sulfate-reducing magnetotactic bacterium, which we designate "strain FSS-1". We found that the strain FSS-1 is a strict anaerobe and uses casamino acids as electron donors and sulfate as an electron acceptor to reduce sulfate to hydrogen sulfide. The strain FSS-1 produced bullet-shaped magnetite nanoparticles in the cells and responded to external magnetic fields. On the basis of 16S rRNA gene sequence analysis, the strain FSS-1 is a member of the genus Desulfovibrio, showing a 96.7% sequence similarity to Desulfovibrio putealis strain B7-43T. Futhermore, the magnetosome gene cluster of strain FSS-1 was different from that of Desulfovibrio magneticus strain RS-1. Thus, the strain FSS-1 is considered to be a novel sulfate-reducing magnetotactic bacterium belonging to the genus Desulfovibrio

Effect of Polyethylene Glycol on the Formation of Magnetic Nanoparticles Synthesized by <i>Magnetospirillum magnetotacticum</i> MS-1

<div><p>Magnetotactic bacteria (MTB) synthesize intracellular magnetic nanocrystals called magnetosomes, which are composed of either magnetite (Fe₃O₄) or greigite (Fe₃S₄) and covered with lipid membranes. The production of magnetosomes is achieved by the biomineralization process with strict control over the formation of magnetosome membrane vesicles, uptake and transport of iron ions, and synthesis of mature crystals. These magnetosomes have high potential for both biotechnological and nanotechnological applications, but it is still extremely difficult to grow MTB and produce a large amount of magnetosomes under the conventional cultural conditions. Here, we investigate as a first attempt the effect of polyethylene glycol (PEG) added to the culture medium on the increase in the yield of magnetosomes formed in <i>Magnetospirillum magnetotacticum</i> MS-1. We find that the yield of the formation of magnetosomes can be increased up to approximately 130 % by adding PEG200 to the culture medium. We also measure the magnetization of the magnetosomes and find that the magnetosomes possess soft ferromagnetic characteristics and the saturation mass magnetization is increased by 7 %.</p></div

Effect of PEGs on the growth of <i>M</i>. <i>magnetotacticum</i> MS-1 and the formation of magnetosomes.

<p><b>*</b> The cell concentration was evaluated, counting directly the number of cells in the culture medium using a Bacteria Counting Chamber.</p><p>*<b>*</b> The average values were obtained from two independent experiments.</p><p>*<b>*</b>* Normalized production rate of magnetosomes <i>P</i> was defined by </p><p></p><p></p><p></p><p><mi>P</mi><mo>=</mo></p><p><mi>C</mi><mi>p</mi></p><mo>×</mo><p><mi>N</mi><mi>p</mi></p><p><mrow></mrow><mrow></mrow></p><mo>/</mo><mo stretchy="false">(</mo><p><mi>C</mi><mn>0</mn></p><mo>×</mo><p><mi>N</mi><mn>0</mn></p><mo stretchy="false">)</mo><mo>,</mo><p></p><p></p><p></p><p></p> where <i>C</i>_<i>p</i> and <i>N</i>_<i>p</i> are, respectively, the final cell concentration and the average number of magnetosomes synthesized in each cell in the presence of PEG, whereas <i>C</i>₀ and <i>N</i>₀ are those in the absence of PEG.<p></p><p>Effect of PEGs on the growth of <i>M</i>. <i>magnetotacticum</i> MS-1 and the formation of magnetosomes.</p

Effect of PEGs added to the culture medium on the growth of <i>M</i>. <i>magnetotacticum</i> MS-1.

<p>The cell concentration was evaluated, counting directly the number of cells in the culture medium using a Bacteria Counting Chamber. The closed circles, squares and triangles, and open circles and squares, respectively, correspond to the growth curves in the absence of PEG and in the presence of PEG200, PEG6,000, PEG20,000, and PEG500,000. The average values were calculated from three independent experiments. The error bars represent the standard deviations.</p