Metallothioneins 1 and 2, but not 3, are regulated by nutritional status in rat white adipose tissue

Background

Cumulating evidence underlines the role of adipose tissue metallothionein (MT) in the development of obesity and type 2 diabetes. Fasting/refeeding was shown to affect MT gene expression in the rodent liver. The influence of nutritional status on MT gene expression in white adipose tissue (WAT) is inconclusive. The aim of this study was to verify if fasting and fasting/refeeding may influence expression of MT genes in WAT of rats.

Results

Fasting resulted in a significant increase in MT1 and MT2 gene expressions in retroperitoneal, epididymal, and inguinal WAT of rats, and this effect was reversed by refeeding. Altered expressions of MT1 and MT2 genes in all main fat depots were reflected by changes in serum MT1 and MT2 levels. MT1 and MT2 messenger RNA (mRNA) levels in WAT correlated inversely with serum insulin concentration. Changes in MT1 and MT2 mRNA levels were apparently not related to total zinc concentrations and MTF1 and Zn transporter mRNA levels in WAT. Fasting or fasting/refeeding exerted no effect on the expression of MT3 gene in WAT. Addition of insulin to isolated adipocytes resulted in a significant decrease in MT1 and MT2 gene expressions. In contrast, forskolin or dibutyryl-cAMP (dB-cAMP) enhanced the expressions of MT1 and MT2 genes in isolated adipocytes. Insulin partially reversed the effect of dB-cAMP on MT1 and MT2 gene expressions.

Conclusions

This study showed that the expressions of MT1 and MT2 genes in WAT are regulated by nutritional status, and the regulation may be independent of total zinc concentration.

     

Influence of quorum sensing signal molecules on biofilm formation in <Emphasis Type="Italic">Proteus mirabilis</Emphasis> O18

The influence of basis of quorum sensing molecules on Proteus strains is much less known as compared to Pseudomonas or Escherichia. We have previously shown that a series of acylated homoserine lactones (acyl-HSL) does not influence the ureolytic, proteolytic, or hemolytic abilities, and that the swarming motility of Proteus mirabilis rods is strain specific. The aim of the presented study was to find out if the presence of a series of acyl-HSL influences biofilm formation of P. mirabilis laboratory strain belonging to O18 serogroup. This serogroup is characterized by the presence of a unique non-carbohydrate component, namely phosphocholine. Escherichia coli and P. mirabilis O18 strains used in this work contains cloned plasmids encoding fluorescent protein genes with constitutive gene expression. In mixed biofilms in stationary and continuous flow conditions, P. mirabilis O18 overgrow whole culture. P. mirabilis O18 strain has genetically proved a presence of AI–2 quorum sensing system. Differences in biofilm structure were observed depending on the biofilm type and culture methods. From tested acylated homoserine lactones (BHL, HHL, OHL, DHL, dDHL, tDHL), a significant influence had BHL on thickness, structure, and the amount of exopolysaccharides produced by biofilms formed by P. mirabilis O18 pDsRed₂.     

Synthesis, physicochemical and pharmacokinetic characterization of calcium uronates

Four calcium compounds containing uronic acids (D(+)-galacturonic and D(+)-glucuronic) in L:M ratio = 2 and 3 were isolated by applying novel (except for one complex) synthetic procedures. The compounds were characterized by elemental analysis, spectroscopic methods (diffuse reflectance and absorption UV-visible, IR, FIR), mass spectrometry, fast atom bombardment (FAB), thermal decomposition, thermogravimetry/derivative thermogravimetry (TG/DTG) data and differential scanning calorimetric studies (DSC). Two modes of water binding in the complexes, i.e., hydration and coordination-like, were established. Computer-aided analysis has shown that further investigations are needed in order to determine the applicability of calcium uronates as calcium carriers.     

Disturbance of ethylene biosynthesis and perception during somatic embryogenesis in <Emphasis Type=Italic>Medicago sativa</Emphasis> L. reduces embryos’ ability to regenerate

Effects of non-specific ethylene biosynthesis inhibitors: salicylic acid (SA) and aminoethoxyvinylglycine (AVG), and of specific inhibitors of ethylene binding to receptors: 1-methylcyclopropene (1-MCP) and 2,5-norbornadiene (NBD) applied during proliferation and differentiation phases of indirect somatic embryogenesis (SE) of Medicago sativa L. cv. Rangelander on embryogenic suspension growth, embryo production, development, and ability to germinate and convert were studied. Application of SA and AVG alone or together at concentrations from 1 to 500 μM in B₅g liquid medium during the proliferation phase had an inhibitory effect on ethylene production and embryogenic suspension growth. Additionally, it caused a drastic reduction in production of embryos and their development on BOi2Y solid differentiation medium. The inhibitory effect of SA was more visible than that of AVG. In addition, disturbance of ethylene biosynthesis during the proliferation phase of SE resulted in diminished lateral germination and conversion of cotyledonary embryos on MS solid medium. Moreover, blocking of ethylene receptors by 1-MCP during the proliferation phase also inhibited ethylene production and embryogenic suspension growth and reduced embryo production during differentiation. MCP almost completely inhibited development of cotyledonary embryos. At the same time, development of more embryos was arrested at the globular stage, and the number of abnormal embryos almost doubled. Similarly, addition of 1-MCP or NBD to the ambient atmosphere during the differentiation phase evidently arrested the development of embryos and, consequently, their ability to germinate and convert on MS regeneration medium. All the results presented above demonstrated that not only ethylene biosynthesis, but also ethylene action is involved in the control of individual phases of SE in Medicago sativa L. cv. Rangelander. And what is more, disturbance of these processes during distinct phases of SE adversely affects vigor of the somatic embryos obtained.     

Thyroid Disorders—Assessments of Trace Elements, Clinical, and Laboratory Parameters

The trace elements studied in this work (Se, Cu, Zn) are the essential constituents or cofactors required to activate numerous enzymes and proteins, playing crucial role in various physiological processes. The disturbed levels of abovementioned elements may adversely affect the endocrine system, resulting in various thyroid disorders among other upsets. The aim of this study was to investigate possible associations between them and parameters of redox balance, thyroid function indices as well as clinical records (duration of disease and therapy, lag time between thyroid surgery and this study examination, LT4 dosage) in patients with different thyroid disorders, including malignant diseases of the gland. In the group of patients with papillary carcinoma, we found a statistically significant higher Cu concentration compared with controls and patients with Hashimoto disease. In the same groups, the parameter of Zn/Cu ratio demonstrated reciprocally arranged statistically significant differences. For the group of papillary cancer patients, there was a negative correlation between lag time since thyroid operation and GPX3 activity. Our data support hypothesis of indirect involvement of Zn and Cu in thyroid regulation. For selenium, lack of simple correlation between its serum level and thyroid indices implies the need for further research on other selenium status parameters more adequately depicting changes in endocrine system.     

Origin and paleoecology of Middle Jurassic hiatus concretions from Poland

Bored and encrusted carbonate concretions, termed hiatus concretions, coming from the Middle Jurassic (Upper Bajocian and Bathonian) siliciclastics of the Polish Jura, south-central Poland, have been subjected to detailed paleoecological investigation for the first time. The concretions possess variable morphology and bear distinct traces of bioerosion and encrustation as a result of exhumation on the sea floor during intervals of low sedimentation and/or erosion. The borings are dominated by Gastrochaenolites and Entobia. Epilithozoans, represented by at least 26 taxa, are dominated by sabellid/serpulid worm tubes and bryozoans, while sponges and corals are minor. No relationship between the concretion size and the number of encrusters has been found, suggesting that concretion size was not the primary factor controlling diversity. Stable isotope analyses and the presence of crustacean scratch marks and Rhizocorallium traces on many of the hiatus concretions indicate that they formed just below the sediment–water interface, within the sulfate reduction zone. Moreover, crustacean activities may have been a prelude to their origin, as shapes of many concretions closely resemble thalassinoidean burrow systems. It is also possible that crustacean activity around the concretions promoted their exhumation by loosening the surrounding soft sediment. The presence of borings and encrusters on different concretion surfaces, as well as truncated borings and a number of abraded epilithozoans, indicate that after the concretions were exhumed they were repeatedly overturned and moved on the sea floor, probably due to episodic storm-related bottom currents in shallow subtidal environment.     

Gene expression profile of medullary thyroid carcinoma--preliminary results

INTRODUCTION: Medullary thyroid carcinoma occurs both as a sporadic and a familial disease. Inherited MTC (iMTC) patients usually exhibit better prognosis than patients with sporadic form of MTC (sMTC), however, in both subtypes the outcome is unpredictable. No molecular markers contributing to the prognosis or predicting the type of therapy have been introduced to clinical practice until now. The aim of this study was to analyze gene expression pattern of MTC by high density oligonucleotide microarray. MATERIAL AND METHODS: 24 samples were studied: 12 MTC and 12 corresponding normal tissues, (Affymetrix HG-U 133A). Among MTC patients there were half inherited cases and half sporadic ones. RESULTS: First, the differences between MTC and thyroid tissue were analyzed by Singular Value Decomposition (SVD) which indicated three main modes determining the variability of gene expression profile: the first two were related to the tumor/normal tissue difference and the third one was related to the immune response. The characteristic expression pattern, beside of numerous changes within cancer- related genes, included many up-regulated genes specific for thyroid C cells. Further analysis of the second component revealed two subgroups of MTC, but the subdivision was not related to the iMTC/sMTC difference. Recursive Feature Replacement (RFR) confirmed the very similar expression profile in both forms of MTC. With subsequent ANOVA analysis some genes with differential expression could be specified, among them monoamine oxidase B (MAOB) and gamma-aminobutyric acid receptor (GABRR1) which were consistently up-regulated in sMTC. In contrary, some genes involved in regulation of cell proliferation: opioid growth factor receptor(OGFR) and synaptotagmin V (SYT 5) were up-regulated in iMTC. CONCLUSIONS: The obtained data indicate a very similar gene expression pattern in inherited and sporadic MTC. Minor differences in their molecular profile require further analysis.     

Is CYP1B1 involved in the metabolism of dioxins in the pig?

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is the most difficult to biodegradate and the most toxic dioxin congener. Previously, we demonstrated in silico the ability of pig CYP1A1 to hydroxylate 2,7-dichlorodibenzo-p-dioxin (DiCDD), but not TCDD. To increase our knowledge concerning the low effectiveness of TCDD biodegradability, we analyzed in silico the binding selectivity and affinity between pig CYP1B1 and the two dioxins by means of molecular modeling. We also compared the effects of TCDD and DiCDD on CYP1B1 gene expression (qRT-PCR) and catalytic (EROD) activity in porcine granulosa cells. It was found that DiCDD and TCDD were stabilized within the pig CYP1B1 active site by hydrophobic interactions. The analysis of substrate channel availability revealed that both dioxins opened the exit channel S, allowing metabolites to leave the enzyme active site. Moreover, DiCDD and TCDD increased the CYP1B1 gene expression and catalytic activity in porcine granulosa cells. On the other hand, TCDD demonstrated higher than DiCDD calculated affinity to pig CYP1B1, hindering TCDD exit from the active site. The great distance between CYP1B1's heme and TCDD also might contribute to the lower hydroxylation effectiveness of TCDD compared to that of DiCDD. Moreover, the narrow active site of pig CYP1B1 may immobilize TCDD molecule, inhibiting its hydroxylation. The results of the access channel analysis and the distance from pig CYP1B1's heme to TCDD suggest that the metabolizing potential of pig CYP1B1 is higher than that of pig CYP1A1. However, this potential is probably not sufficiently high to considerably improve the slow TCDD biodegradation.     

RVX-208, an Inducer of ApoA-I in Humans,Is a BET Bromodomain Antagonist

Increased synthesis of Apolipoprotein A-I (ApoA-I) and HDL is believed to provide a new approach to treating atherosclerosis through the stimulation of reverse cholesterol transport. RVX-208 increases the production of ApoA-I in hepatocytes in vitro, and in vivo in monkeys and humans, which results in increased HDL-C, but the molecular target was not previously reported. Using binding assays and X-ray crystallography, we now show that RVX-208 selectively binds to bromodomains of the BET (Bromodomain and Extra Terminal) family, competing for a site bound by the endogenous ligand, acetylated lysine, and that this accounts for its pharmacological activity. siRNA experiments further suggest that induction of ApoA-I mRNA is mediated by BET family member BRD4. These data indicate that RVX-208 increases ApoA-I production through an epigenetic mechanism and suggests that BET inhibition may be a promising new approach to the treatment of atherosclerosis.