Extremely Low-Frequency Magnetic Field Decreased Calcium,Zinc and Magnesium Levels in Costa of Rat

Electromagnetic field (EMF) can affect cells due to biochemical change followed by a change in level of ions trafficking through membrane. We aimed to investigate possible changes in some elements in costa of rats exposed to long-term extremely low-frequency magnetic field (ELF-MF). Rats were exposed to 100 and 500 μT ELF-MF, which are the safety standards of public and occupational exposure for 2 h/day during 10 months. At the end of the exposure period, the samples of costa were taken from the rats exposed to ELF-MF and sham. The levels of elements were measured by using atomic absorption spectrophotometry (AAS) and ultraviolet (UV) spectrophotometry. Ca levels decreased in the ELF-500 exposure group in comparison to sham group (p < 0.05). Statistically significant decrease was found in Mg levels in the ELF-500 exposure group in comparison to sham and ELF-100 exposure groups (p < 0.05). Zn levels were found to be lower in the ELF-500 exposure group than those in the sham and ELF-100 exposure groups (p < 0.05). No significant differences were determined between groups in terms of the levels of P, Cu and Fe. In conclusion, it can be maintained that long-term ELF-MF exposure can affect the chemical structure and metabolism of bone by changing the levels of some important elements such as Ca, Zn and Mg in rats.     

Prevention of ischemia-reperfusion injury in rat ovarian tissue with the on-off method

Ischemia is defined as cell death caused by insufficient perfusion of the tissue due to reduction in arterial or venous blood flow, depletion of cellular energy storages, and accumulation of toxic metabolites. The positive effects of controlled reperfusion are known and are used clinically. But the positive effects of controlled reperfusion on ovarian tissue have not been seen in the literature yet. The biochemical and histopathological comparative investigation of rat ovaries that were experimentally exposed to ischemia (IG), ischemia-reperfusion (I/R), and ischemia-controlled reperfusion (ICR) was aimed. Forty rats were divided into four groups (10 rats per group). First group: 3 h ischemia by vascular clips on ovarian tissue. Second group: 3 h ischemia + 1 h reperfusion. Third group: 3 h ischemia + 1 h controlled reperfusion (on-off method: controlled reperfusion by opening and closing the clips (on/off) in 10-second intervals, for 5 times for a total of 100 seconds). Fourth group: healthy rats. Biochemical (tGSH, MDA, and DNA damage level and SOD activity) and histopathological analysis were performed. The highest glutathione and superoxide dismutase measurements were found in ischemia/controlled reperfusion group among the ischemia or ischemia/reperfusion groups. Similarly the damage indicators (malondialdehyde, DNA damage level and histopathological damage grade) were the lowest in ischemia/controlled reperfusion group. These results indicate that controlled reperfusion can be helpful in minimizing ischemia-reperfusion injury in ovarian tissue exposed to ischemia for various reasons (ovarian torsion, tumor, etc.).     

Water exchange in manganese-based water-oxidizing catalysts in photosynthetic systems: From the water-oxidizing complex in photosystem II to nano-sized manganese oxides

The water-oxidizing complex (WOC), also known as the oxygen-evolving complex (OEC), of photosystem II in oxygenic photosynthetic organisms efficiently catalyzes water oxidation. It is, therefore, responsible for the presence of oxygen in the Earth's atmosphere. The WOC is a manganese–calcium (Mn₄CaO₅(H₂O)₄) cluster housed in a protein complex. In this review, we focus on water exchange chemistry of metal hydrates and discuss the mechanisms and factors affecting this chemical process. Further, water exchange rates for both the biological cofactor and synthetic manganese water splitting are discussed. The importance of fully unveiling the water exchange mechanism to understand the chemistry of water oxidation is also emphasized here. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: Keys to Produce Clean Energy.     

Frequently asked questions about in vivo chlorophyll fluorescence: practical issues

The aim of this educational review is to provide practical information on the hardware, methodology, and the hands on application of chlorophyll (Chl) a fluorescence technology. We present the paper in a question and answer format like frequently asked questions. Although nearly all information on the application of Chl a fluorescence can be found in the literature, it is not always easily accessible. This paper is primarily aimed at scientists who have some experience with the application of Chl a fluorescence but are still in the process of discovering what it all means and how it can be used. Topics discussed are (among other things) the kind of information that can be obtained using different fluorescence techniques, the interpretation of Chl a fluorescence signals, specific applications of these techniques, and practical advice on different subjects, such as on the length of dark adaptation before measurement of the Chl a fluorescence transient. The paper also provides the physiological background for some of the applied procedures. It also serves as a source of reference for experienced scientists.     

Ancient split of major genetic lineages of European Black Pine: evidence from chloroplast <Emphasis>DNA</Emphasis>

The European Black Pine (Pinus nigra Arn.) has a long and complex history. Genetic distance and frequency analyses identified three differentiated genetic groups, which corresponded to three wide geographical areas: Westerns Mediterranean, Balkan Peninsula and Asia Minor. These groups shared common ancestors (14.75 and 10.72 Ma). The most recent splits occurred after the Messinian Salinity Crisis (4.37 Ma) and the Early–Middle Pleistocene Transitions (0.93 Ma). The posterior ancestral population size (Na) is 260,000–265,000 individuals. Each pool is further fragmented, with evidence of a phylogeographic structure (N _st  > G _st ) typically observed in some natural populations from the Western Mediterranean region and the Balkan Peninsula. The laboratory analysis was performed by fragment analysis—i.e. electrophoretic sizing of polymerase chain reaction fragments, combined with the sequencing analysis of 33 % of all individuals as a control. Intense sampling of chloroplast DNA polymorphisms (3154 individuals and 13 markers: SNPs and SSRs) over the full area of the species’ natural distribution indicated moderate among-population variability (G _st(nc) ≤ 0.177) in various parts of its range. These results indicate that the natural populations have long migration histories that differ from one another and that they have been strongly phylogeographically affected by complex patterns of isolation, speciation and fragmentation. Long and varying climatic fluctuations in the region of the principal genetic group have been the probable cause of different forest community associations with different successional patterns resulting in interglacial refugia vs. macro long-term refugia.     

Carbonic anhydrase inhibitors. Synthesis of 2,4,6-trimethylpyridinium derivatives of 2-(hydrazinocarbonyl)-3-aryl-1H-indole-5-sulfonamides acting as potent inhibitors of the tumor-associated isoform IX and XII

A series of 2-(hydrazinocarbonyl)-3-aryl-1H-indole-5-sulfonamides possessing various 2-, 3- or 4- substituted phenyl groups with methyl-, halogeno- and methoxy-functionalities, or a perfluorophenyl moiety, has been derivatized by reaction with 2,4,6-trimethylpyrylium perchlorate. The new sulfonamides were evaluated as inhibitors of four mammalian carbonic anhydrase (CA, EC 4.2.1.1) isoforms, that is, CA I, II (cytosolic), CA IX and XII (transmembrane, tumor-associated forms). Excellent inhibitory activity was observed against hCA IX with most of these sulfonamides, and against hCA XII with some of the new compounds. These compounds were generally less effective inhibitors of hCA II. Being membrane impermeant, these positively-charged sulfonamides are interesting candidates for targeting the tumor-associated CA IX and XII, as possible diagnostic tools or therapeutic agents.     

Systematic analysis of the relation of electron transport and ATP synthesis to the photodamage and repair of photosystem II in Synechocystis

The photosynthetic machinery and, in particular, the photosystem II (PSII) complex are susceptible to strong light, and the effects of strong light are referred to as photodamage or photoinhibition. In living organisms, photodamaged PSII is rapidly repaired and, as a result, the extent of photoinhibition represents a balance between rates of photodamage and the repair of PSII. In this study, we examined the roles of electron transport and ATP synthesis in these two processes by monitoring them separately and systematically in the cyanobacterium Synechocystis sp. PCC 6803. We found that the rate of photodamage, which was proportional to light intensity, was unaffected by inhibition of the electron transport in PSII, by acceleration of electron transport in PSI, and by inhibition of ATP synthesis. By contrast, the rate of repair was reduced upon inhibition of the synthesis of ATP either via PSI or PSII. Northern blotting and radiolabeling analysis with [(35)S]Met revealed that synthesis of the D1 protein was enhanced by the synthesis of ATP. Our observations suggest that ATP synthesis might regulate the repair of PSII, in particular, at the level of translation of the psbA genes for the precursor to the D1 protein, whereas neither electron transport nor the synthesis of ATP affects the extent of photodamage.     

Pilus Gene Pool Variation and the Virulence of Corynebacterium diphtheriae Clinical Isolates during Infection of a Nematode

Toxigenic Corynebacterium diphtheriae strains cause diphtheria in humans. The toxigenic C. diphtheriae isolate NCTC13129 produces three distinct heterotrimeric pili that contain SpaA, SpaD, and SpaH, making up the shaft structure. The SpaA pili are known to mediate bacterial adherence to pharyngeal epithelial cells. However, to date little is known about the expression of different pili in various clinical isolates and their importance in bacterial pathogenesis. Here, we characterized a large collection of C. diphtheriae clinical isolates for their pilin gene pool by PCR and for the expression of the respective pilins by immunoblotting with antibodies against Spa pilins. Consistent with the role of a virulence factor, the SpaA-type pili were found to be prevalent among the isolates, and most significantly, corynebacterial adherence to pharyngeal epithelial cells was strictly correlated with isolates that were positive for the SpaA pili. By comparison, the isolates were heterogeneous for the presence of SpaD- and SpaH-type pili. Importantly, using Caenorhabditis elegans as a model host for infection, we show here that strain NCTC13129 rapidly killed the nematodes, the phenotype similar to isolates that were positive for toxin and all pilus types. In contrast, isogenic mutants of NCTC13129 lacking SpaA-type pili or devoid of toxin and SpaA pili exhibited delayed killing of nematodes with similar kinetics. Consistently, nontoxigenic or toxigenic isolates that lack one, two, or all three pilus types were also attenuated in virulence. This work signifies the important role of pili in corynebacterial pathogenesis and provides a simple host model to identify additional virulence factors.     

Genome-wide identification and cadmium induced expression profiling of sulfate transporter (<Emphasis Type="Italic">SULTR</Emphasis>) genes in sorghum (<Emphasis Type="Italic">Sorghum bicolor</Emphasis> L.)

Sulfur is an essential element for all living organisms. Plants can convert inorganic sulfur into organic sulfur compounds by complex enzymatic steps. In this study, we conducted a genome-wide analysis of sulfate transporter genes (SULTRs) in the sorghum (Sorghum bicolor) genome and examined expression profiles of SbSULTR genes under 200 µM cadmium (Cd) exposure. As a result of sorghum genome analysis, 11 SULTR genes were identified, including SbSULTR1;1, SbSULTR1;2, SbSULTR1;3, SbSULTR2;1, SbSULTR2;2, SbSULTR3;1, SbSULTR3;2, SbSULTR3;3, SbSULTR3;4, SbSULTR3;5, and SbSULTR4. Given names are based on phylogeny and chromosomal locations. Except SbSULTR4, all SbSULTR proteins contained Sulfate_transp (PF00916), STAS (PF01740) domains and 12 trans-membrane domains. Phylogenetic analysis revealed that four major groups were identified such as SULTR1, 2, 3, and 4 groups and SULTR4 group was separated to other SULTR groups. In promotor sequences of SbSULTR genes, many diverse cis-acting elements were found mainly related with physiological processes such as light, stress and hormone responsiveness. The expression profiles of SbSULTR genes showed that SULTR1;2, 1;3, 3;3, and 3;5 genes up-regulated in root, while expression level of SULTR4 decreased under 200 µM Cd exposure. The predicted 3D structures of SULTR proteins showed some conformational changes, suggesting functional diversities of SbSULTRs. Finally, results of this study may contribute towards understanding SbSULTR genes and their regulations and roles in Cd stress in sorghum.