Exogenously Treated Mammalian Sex Hormones Affect Inorganic Constituents of Plants

The present study was undertaken to reveal the changes in inorganic constituents of plants exposed to mammalian sex hormones (MSH). Chickpea leaves were sprayed with 10⁻⁴, 10⁻⁶, 10⁻⁹, 10⁻¹², and 10⁻¹⁵ M concentrations of progesterone, β-estradiol, and androsterone at 7th day after sowing. The plants were harvested at the end of 18 days after treatment of MSH solutions and the inorganic components determined using a wavelength-dispersive X-ray fluorescence spectroscopy technique. At all of the concentrations tested, MSH significantly increased the contents of K, S, Na, Ca, Mg, Zn, Fe, P, Cu, and Ni. Interestingly, only Mn and Cl contents decreased. The maximum changes in the inorganic composition were recorded at 10⁻⁶ M for plants treated with progesterone and 10⁻⁹ M for plants treated with β-estradiol and androsterone.     

siRNA screening of the kinome identifies ULK1 as a multidomain modulator of autophagy

Autophagy is a vital response to nutrient starvation. Here, we screened a kinase-specific siRNA library using an autophagy assay in human embryonic kidney 293 cells that measures lipidation of the marker protein GFP-LC3 following amino acid starvation. This screen identified ULK1 in addition to other novel candidates that could be confirmed with multiple siRNAs. Knockdown of ULK1, but not the related kinase ULK2, inhibited the autophagic response. Also, ULK1 knockdown inhibited rapamycin-induced autophagy consistent with a role downstream of mTOR. Overexpression of ULK1 inhibited autophagy and this inhibition was independent of its kinase activity. Deletion of the PDZ domain-binding Val-Tyr-Ala motif at the ULK1 C terminus generated a more potent dominant-negative protein. Further deletions revealed that the minimal ULK1 dominant-negative region could be mapped to residues 1-351. Full-length ULK1 localized to cytoplasmic structures, some of which were GFP-LC3-positive, and this localization required the conserved C-terminal domain. In contrast, ULK1-(1-351) was diffuse in the cytoplasm. These experiments reveal at least two domains in ULK1 which likely function via unique sets of effectors to regulate autophagy.     

Cytogenetic effects of extremely low frequency magnetic field on Wistar rat bone marrow

In this study, the genotoxic and cytotoxic potential of extremely low frequency magnetic fields (ELF-MF) was investigated in Wistar rat tibial bone marrow cells, using the chromosomal aberration (CA) and micronucleus (MN) test systems. In addition to these test systems, we also investigated the mitotic index (MI), and the ratio of polychromatic erythrocytes (PCEs) to normochromatic erythrocytes (NCEs). Wistar rats were exposed to acute (1 day for 4 h) and long-term (4 h/day for 45 days) to a horizontal 50 Hz, 1 mT uniform magnetic field generated by a Helmholtz coil system. Mitomycin C (MMC, 2 mg/kg BW) was used as positive control. Results obtained by chromosome analysis do not show any statistically significant differences between the negative control and both acute and long-term ELF-MF exposed samples. When comparing the group mean CA of long-term exposure with the negative control and acute exposure, the group mean of the long-term exposed group was higher, but this was not statistically significant. However, the mean micronucleus frequency of the longer-term exposed group was considerably higher than the negative control and acutely exposed groups. This difference was statistically significant (p < 0.01). The results of the MI in bone marrow showed that the averages of both A-MF and L-MF groups significantly decreased when compared to those in the negative control (p < 0.001 and p < 0.01, respectively). No significant differences were found between the group mean MI of A-MF exposure with L-MF. We found that the average of PCEs/NCEs ratios of A-MF exposed group was significantly lower than the negative control and L-MF exposed groups (p < 0.001 and p < 0.01, respectively). In addition, the group mean of the PCEs/NCEs ratios of L-MF was significantly lower than negative control (p < 0.01). We also found that the MMC treated group showed higher the number of CA and the frequency of MN formation when compared to those in all other each groups (p-values of all each groups <0.01) and also MMC treated group showed lower MI and the PCEs/NCEs ratios when compared to those in all other each groups (p-values of all groups <0.01). These observations indicate the in vivo suspectibility of mammals to the genotoxicity potential of ELF-MF.     

The regulatory effects of clomiphene and tamoxifen on mTOR and LC3-II expressions in relation to autophagy in experimental polycystic ovary syndrome (PCOS)

Molecular Biology Reports - Polycystic ovary syndrome (PCOS) is a metabolic disease that causes infertility due to anovulation in women in reproductive age. It is known that clomiphene citrate (CC)...     

Secreted amyloid precursor protein β and secreted amyloid precursor protein α induce axon outgrowth in vitro through Egr1 signaling pathway

Background

sAPPα released after α secretase cleavage of Amyloid Precursor Protein (APP) has several functions including the stimulation of neurite outgrowth although detailed morphometric analysis has not been done. Two domains involved in this function have been described and are present in sAPPβ released at the first step of amyloid peptide cleavage, raising the possibility that sAPPβ could also stimulate neurite outgrowth. We investigated the morphological effects of sAPPα and sAPPβ on primary neurons and identified a key signaling event required for the changes observed.

Methodology/Principal Findings

Final concentrations of 50 to 150 nM bacterial recombinant sAPPα or sAPPβ added to primary neuronal cultures after 1 day in vitro decreased cell adhesion 24 hours later and primary dendrite length 96 hours later. 150 nM sAPPα and sAPPβ induced a similar increase of axon outgrowth, although this increase was already significant at 100 nM sAPPα. These morphological changes induced by sAPPs were also observed when added to differentiated neurons at 5 days in vitro. Real time PCR and immunocytochemistry showed that sAPPα and sAPPβ stimulated Egr1 expression downstream of MAPK/ERK activation. Furthermore, in primary neurons from Egr1 −/− mice, sAPPs affected dendritic length but did not induce any increase of axon length.

Conclusion/Significance

sAPPα and sAPPβ decrease cell adhesion and increase axon elongation. These morphological changes are similar to what has been observed in response to heparan sulfate. The sAPPα/sAPPβ stimulated increase in axon growth requires Egr1 signaling. These data suggest that sAPPβ is not deleterious per se. Since sAPPβ and sAPPα are present in the embryonic brain, these two APP metabolites might play a role in axon outgrowth during development and in response to brain damage.     

Immobilization of tyrosinase in polysiloxane/polypyrrole copolymer matrices

Immobilization of tyrosinase in conducting copolymer matrices of pyrrole functionalized polydimethylsiloxane/polypyrrole (PDMS/PPy) was achieved by electrochemical polymerization. The polysiloxane/polypyrrole/tyrosinase electrode was constructed by the entrapment of enzyme in conducting matrices during electrochemical copolymerization. Maximum reaction rate (V(max)) and Michaelis-Menten constant (K(m)) were investigated for immobilized enzyme. Enzyme electrodes were prepared in two different electrolyte/solvent systems. The effect of supporting electrolytes, p-toluene sulfonic acid and sodium dodecyl sulfate on the enzyme activity and film morphology were determined. Temperature and pH optimization, operational stability and shelf-life of enzyme electrodes were also examined. Phenolic contents of green and black tea were determined by using enzyme electrodes.     

Efficient <Emphasis Type="Italic">in vitro</Emphasis> bulblet regeneration from immature embryos of endangered <Emphasis Type="Italic">Sternbergia fischeriana</Emphasis>

Sternbergia fischeriana is an endangered geophyte and therefore in vitro micropropagation of this plant will have great importance for germplasm conservation and commercial production. Bulb scale and immature embryo explants of S. fischeriana were cultured on different nutrient media supplemented with various concentrations of plant growth regulators. Immature embryos produced higher number of bulblets than bulb scales. Large numbers of bulblets were regenerated (over 80 bulblets/explants) from immature embryos on Murashige and Skoog (MS) medium supplemented with 4 mg l^–1 6-benzylaminopurine (BA) and 0.25 mg l^–1 -naphthaleneacetic (NAA) or 2 mg l^–12,4-dichlorophenoxyacetic acid (2,4-D) after 14 months of culture initiation. Regenerated bulblets were kept at 5 °C for 5 weeks and then transplanted to a potting mixture.     

Characterization of neutralizing monoclonal antibodies recognizing a 15-residues epitope on the spike protein HR2 region of severe acute respiratory syndrome coronavirus (SARS-CoV)

Summary The spike (S) glycoprotein is thought to play a complex and central role in the biology and pathogenesis of SARS coronavirus infection. In this study, a recombinant protein (rS268, corresponding to residues 268–1255 of SARS-CoV S protein) was expressed in Escherichia coli and was purified to near homogeneity. After immunization with rS268, S protein-specific BALB/c antisera and mAbs were induced and confirmed using ELISA, Western blot and IFA. Several BALB/c mAbs were found to be effectively to neutralize the infection of Vero E6 cells by SARS-CoV in a dose-dependent manner. Systematic epitope mapping showed that all these neutralizing mAbs recognized a 15-residues peptide (CB-119) corresponding to residues 1143–1157 (SPDVDLGDISGINAS) that was located to the second heptad repeat (HR2) region of the SARS-CoV spike protein. The peptide CB-119 could specifically inhibit the interaction of neutralizing mAbs and spike protein in a dose-dependent manner. Further, neutralizing mAbs, but not control mAbs, could specifically interact with CB-119 in a dose-dependent manner. Results implicated that the second heptad repeat region of spike protein could be a good target for vaccine development against SARS-CoV.     

Mesna (2-mercaptoethane sulfonate) prevents ischemia/reperfusion induced renal oxidative damage in rats

Reoxygenation of the ischemic tissue promotes the generation of various reactive oxygen metabolites (ROM) which are known to have deleterious effects on various cellular functions. This study was designed to determine the possible protective effect of mesna (2-Mercaptoethane Sulfonate) on renal ischemia/reperfusion (I/R) injury. Wistar albino rats were unilaterally nephrectomized, and 15 days later they were subjected to 45 min of renal pedicle occlusion followed by 6 h of reperfusion. Mesna (MESNA, 150 mg/kg, i.p.; an effective dose against I/R injury) or vehicle was administered twice, 15 min prior to ischemia and immediately before the reperfusion period. At the end of the reperfusion period, rats were killed by decapitation. Kidney samples were taken for histological examination or determination of the free radicals, renal malondialdehyde (MDA) and glutathione (GSH) levels, and myeloperoxidase (MPO) activity. Renal tissue collagen content, as a fibrosis marker was also determined. Creatinine and urea concentrations in blood were measured for the evaluation of renal function. The results demonstrated that renal I/R caused nephrotoxicity, as evidenced by increases in blood urea and creatinine levels, which was reversed by MESNA treatment. Increased free radical levels, as assessed by nitroblue-tetrazolium test were reduced with MESNA. Moreover, the decrease in GSH and increases in MDA levels, and MPO activity induced by I/R indicated that renal injury involves free radical formation. Treatment of rats with MESNA restored the reduced GSH levels while it decreased MDA levels as well as MPO activity. Increased collagen contents of the kidney tissues by I/R were reversed back to the control levels by MESNA treatment. Since MESNA administration reversed these oxidant responses, improved renal function and microscopic damage, it seems likely that MESNA protects kidney tissue against I/R induced oxidative damage.