Juvenile hormone (JH) controls insect development, metamorphosis and reproduction. In insect hemolymph a significant proportion of JH is bound to juvenile hormone binding protein (JHBP), which serves as a carrier supplying the hormone to the target tissues. To shed some light on JHBP passage within insect tissues, the interaction of this carrier with other proteins from Galleria mellonella (Lepidoptera) was investigated. Our studies revealed the presence of JHBP within the tracheal epithelium and fat body cells in both the membrane and cytoplasmic sections. We found that the interaction between JHBP and membrane proteins occurs with saturation kinetics and is specific and reversible. ATP synthase was indicated as a JHBP membrane binding protein based upon SPR-BIA and MS analysis. It was found that in G. mellonella fat body, this enzyme is present in mitochondrial fraction, plasma membranes and cytosol as well. In the model system containing bovine F(1) ATP synthase and JHBP, the interaction between these two components occurs with K(d)=0.86 nM. In hemolymph we detected JHBP binding to apolipophorin, arylphorin and hexamerin. These results provide the first demonstration of the physical interaction of JHBP with membrane and hemolymph proteins which can be involved in JHBP molecule traffic.

Metallothionein (MT) is a protein involved in numerous key processes, and the most important include zinc ion homeostasis, detoxification of heavy metals, and protection against oxidative stress. MT by interaction with other proteins fulfills its function, resulting in different effects in the body. Interaction of MT with ferritin, which causes a redox reaction, resulting in the reduction of Fe(3+) stored in ferritin and a release of harmful Fe(2+) , was observed. Referring to the redox function of MT, it has been shown that the pair of GSH/GSSG modulates transfer of Zn between MT and Zn-binding proteins. Furthermore, it was shown that GSSG, in the presence of GSH, interacts directly with MT. Apothionein-MT can retrieve Zn from the transcription factors or Zn-containing enzymes. Apothionein-MT by taking Zn can deactivate metal-dependent enzymes while Zn-MT has the opposite effect. As the effect of MT interaction with low-density lipoprotein receptors-megalin and lipoprotein receptor related protein 1, the uptake of Cd-MT occurs and results in the disruption of many functions of proximal tubules. MT is involved in numerous processes and many of them are regulated by protein-protein interactions. Possibly in the future MT will become a therapeutic agent, which will result in a breakthrough in the field of pharmacy and medicine.

Abstract:Staphylococcus aureus obtained from a University Hospital in Poland were characterized in relation to resistance to aminoglycoside antibiotics and the distribution of the genes encoding the most clinically relevant aminoglycoside modifying enzymes (AMEs). Of a total of 118 S. aureus, 45 (38.1%) isolates were found to be resistant to at least one of the tested antibiotics. All aminoglycoside resistant isolates except one 44 (97.8%) were resistant to kanamycin. The majority of strains 37 (82.2%) and 32 (71.1%) expressed resistance to neomycin and tobramycin, respectively. Eleven strains (24.4%) were resistant to gentamicin or amikacin. All S. aureus strains were sensitive to netilmicin. The most prevalent resistance gene was aac(6')-Ie+aph(2') found in 13 (28.9%) strains and 12 (26.7%) isolates carried ant(4')-Ia gene, whilst aph(3')-IIIa gene was detected in only 7 (15.6%) isolates. Additionally, the ant(6)-Ia and str genes were detected in 14 (31.1%) and 2 (4.4%) strains, respectively. Ten (22.2%) strains resistant to amikacin, tobramycin, kanamycin or neomycin did not harbor any of the above-noted genes.

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The aim of the study was to verify if there is any association between exposure to Cu, Zn, Cd, Pb, As and the formation of malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), advanced oxidation protein products (AOPP), and whether in this process cigarette smoking plays a role. The investigations were performed in the 352 smelters occupationally exposed to heavy metals and 73 persons of control group. Metals concentration was determined by atomic absorption spectrometry. MDA and AOPP concentrations were determined by spectrophotometric methods. The concentration of 8-OHdG was determined by ELISA method. It was demonstrated an increased Cu concentration in smoking smelters compared to non-smoking control group. It was noted no differences in Zn and Mg concentrations between the examined groups. Pb concentration was more than sixfold higher in the group of smoking smelters and about fivefold higher in the group of non-smoking smelters compared to the control groups (smokers and non-smokers). It was shown that Cd concentration in the blood was nearly fivefold higher in the smoking control group compared to the non-smoking control group and more than threefold higher in the group of smoking smelters compared to non-smoking. It was shown an increased As concentration (more than fourfold) and decreased Ca concentration in both groups of smelters compared to control groups. In groups of smelters (smokers and non-smokers), twofold higher MDA and AOPP concentrations, and AOPP/albumin index compared to control groups (smokers and non-smokers) were shown. Tobacco smoke is the major source of Cd in the blood of smelters. Occupational exposure causes accumulation of Pb in the blood. Occupational exposure to heavy metals causes raise of MDA concentration and causes greater increase in AOPP concentration than tobacco smoke.