Rotifera from north and northeast Anatolia (Turkey)

Samples from 21 freshwater sites in Turkey yielded 91 different species of Rotifera, 42 of which are new to the Turkish fauna. Lepadella costatoides n. sp. is described and L. costata Wulfert is redescribed. L. christineae Koste is synonymised with L. quinquecostata (Lucks). Remarks on the intraspecific variability of some species of Lecane are given. L. pomiformis Edmondson is added to the synonymy of L. pyriformis (Daday). The synonymy of the latter with L. paraclosterocerca Pennak is confirmed.     

The effect of vascular complications of diabetes mellitus on human umbilical cord tissue and the number of Wharton Jelly’s mesenchymal stem cells

Molecular Biology Reports - The current study investigated the change in umbilical cord tissue and the number of markers of Wharton’s jelly mesenchymal stem cells (WJ-MSC) in pregnant women...     

Combination of AT-101/cisplatin overcomes chemoresistance by inducing apoptosis and modulating epigenetics in human ovarian cancer cells

We investigated the effects of AT-101/cisplatin combination treatment on the expression levels of apoptotic proteins and epigenetic events such as DNA methyltransferase (DNMT) and histone deacetylase (HDAC) enzyme activities in OVCAR-3 and MDAH-2774 ovarian cancer cells. XTT cell viability assay was used to evaluate cytotoxicity. For showing apoptosis, both DNA Fragmentation and caspase 3/7 activity measurements were performed. The expression levels of apoptotic proteins were assessed by human apoptosis antibody array. DNMT and HDAC activities were evaluated by ELISA assay and mRNA levels of DNMT1 and HDAC1 genes were quantified by qRT-PCR. Combination of AT-101/cisplatin resulted in strong synergistic cytotoxicity and apoptosis in human ovarian cancer cells. Combination treatment reduced some pivotal anti-apoptotic proteins such as Bcl-2, HIF-1A, cIAP-1, XIAP in OVCAR-3 cells, whereas p21, Bcl-2, cIAP-1, HSP27, Clusterin and XIAP in MDAH-2774 cells. Among the pro-apoptotic proteins, Bad, Bax, Fas, phospho-p53 (S46), Cleaved caspase-3, SMAC/Diablo, TNFR1 and Cytochrome c were induced in OVCAR-3 cells, whereas, Bax, TRAILR2, FADD, p27, phospho-p53 (S46), Cleaved caspase-3, Cytochrome c, SMAC/Diablo and TNFR1 were induced in MDAH-2774 cells. Combination treatment also inhibited both DNMT and HDAC activities and also mRNA levels in both ovarian cancer cells. AT-101 exhibits great potential in sensitization of human ovarian cancer cells to cisplatin treatment in vitro, suggesting that the combination of AT-101 with cisplatin may hold great promise for development as a novel chemotherapeutic approach to overcome platinum-resistance in human ovarian cancer.     

Parameters affecting substance P measurement in heart, lung, and skin

Substance P (SP), a neuropeptide that is widely distributed both peripherally and centrally, mediates several pathophysiological processes. Among current assays for SP, enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay (RIA) have been most widely used. Several previous studies, mostly performed with nerve extracts or organ perfusates, determined that acidity of the extraction buffer as well as the number extractions performed constitute factors influencing accurate measurements. We used an ELISA protocol in this study to analyze methodological aspects of SP measurement in extracts from heart, skin, and lung. The extraction procedure had two steps, an acid extraction followed by a column extraction. We could effectively measure SP with extract from as little as 10 mg of tissue. For each tissue examined, different variables influenced the SP measured. For all tissues, the weight of tissue extracted was critical; the more tissue extracted, the lower the sensitivity of the assay. This problem could be overcome in skin by omitting the column extraction. When mechanical loses were considered (e.g., loss during extraction and SP retained by the column after elution), column extraction improved SP measurements only with lung tissue. The amount of SP remaining in the sample after the first extraction also varied among tissues. The first acid extraction effectively isolated 80% of total SP from skin. In contrast, the first extraction with lung tissue recovered only 58%. Because both acid and heat effectively release SP from nerve endings, this could reflect the presence of non-neuronal SP, especially in lung. High-dose capsaicin treatment, which depletes SP in nerve endings, caused 42% loss of SP in skin independent of amount of tissue extracted Our results suggest that a second acid extraction of tissue should be performed and that column extraction is clearly detrimental with skin samples.     

Phospholipase C inhibitors and prostaglandins differentially regulate phosphatidylcholine synthesis in rat renal papilla. Evidence of compartmental regulation of CTP:phosphocholine cytidylyltransferase and CDP-choline:1,2-diacylglycerol cholinephosphotransferase

Phosphatidylcholine (PC) is the most abundant phospholipid in mammalian cell membranes. Several lines of evidence support that PC homeostasis is preserved by the equilibrium between PC biosynthetic enzymes and phospholipases catabolic activities. We have previously shown that papillary synthesis of PC depends on prostaglandins (PGs) that modulate biosynthetic enzymes. In papillary tissue, under bradikynin stimulus, arachidonic acid (AA) mobilization (the substrate for PG synthesis) requires a previous phospholipase C (PLC) activation. Thus, in the present work, we study the possible involvement of PLC in PC biosynthesis and its relationship with PG biosynthetic pathway on the maintenance of phospholipid renewal in papillary membranes; we also evaluated the relevance of CDP-choline pathway enzymes compartmentalization. To this end, neomycin, U-73122 and dibutiryl cyclic AMP, reported as PLC inhibitors, were used to study PC synthesis in rat renal papilla. All the PLC inhibitors assayed impaired PC synthesis. PG synthesis was also blocked by PLC inhibitors without affecting cyclooxygenase activity, indicating a metabolic connection between both pathways. However, we found that PC biosynthesis decrease in the presence of PLC inhibitors was not a consequence of PG decreased synthesis, suggesting that basal PLC activity and PGs exert their effect on different targets of PC biosynthetic pathway. The study of PC biosynthetic enzymes showed that PLC inhibitors affect CTP:phosphocholine cytidylyltransferase (CCT) activity while PGD(2) operates on CDP-choline:1,2-diacylglycerol cholinephosphotransferase (CPT), both activities associated to papillary enriched-nuclei fraction. The present results suggest that renal papillary PC synthesis is a highly regulated process under basal conditions. Such regulation might occur at least at two different levels of the CDP-choline pathway: on the one hand, PLC operates on CCT activity; on the other, while PGs regulate CPT activity.     

Salicylic acid induced changes on some physiological parameters symptomatic for oxidative stress and mineral nutrition in maize (Zea mays L.) grown under salinity

It has been proposed that salicylic acid (SA) acts as an endogenous signal molecule responsible for inducing abiotic stress tolerance in plants. The effect of varying salicylic acid (SA) supply (0, 0.1, 0.5 and 1.0mM) on growth, mineral uptake, membrane permeability, lipid peroxidation, H(2)O(2) concentration, UV-absorbing substances, chlorophyll and carotenoid concentrations of NaCl (40 mM) stressed maize (Zea mays L.) was investigated. Exogenously applied SA increased plant growth significantly both in saline and non-saline conditions. As a consequence of salinity stress, lipid peroxidation, measured in terms of malondialdehyde (MDA) content and membrane permeability was decreased by SA. UV-absorbing substances (UVAS) and H(2)O(2) concentration were increased by increasing levels of SA. SA also strongly inhibited Na(+) and Cl(-) accumulation, but stimulated N, Mg, Fe, Mn and Cu concentrations of salt stressed maize plants. These results suggest that SA could be used as a potential growth regulator to improve plant salinity stress resistance.     

Ubiquitously expressed hematological and neurological expressed 1 downregulates Akt-mediated GSK3β signaling, and its knockdown results in deregulated G2/M transition in prostate cells

As the molecular mechanism of β-catenin deregulation is not well understood, and stabilized β-catenin is known to translocate into the nucleus and activate genes for proliferation, a novel regulatory factor, hematological and neurological expressed 1 (HN1), for Akt-GSK3β-β-catenin axis is reported here. In our studies, HN1 gene structure was characterized. HN1 expression was found to be epidermal growth factor-responsive in PC-3 cells, and protein expression was also upregulated in PC-3 and LNCaP but not in DU145 cells. Additionally, HN1 was found to be downregulated by the specific AKT inhibitor wortmannin but not with PI3K or MAPK inhibitors, LY294002 and PD98059, respectively, in PC-3 and MCF-7 cells. Further, siRNA-mediated knockdown of HN1 resulted in considerable increase in Akt((S473)) and GSK3β((S9),(Y216)) phosphorylations; moreover, subsequent accumulation of β-catenin, increase in c-myc expression, and nuclear accumulation of cyclin D1 were observed in PC-3 cells. Knockdown of HN1 also resulted in prolongation of G(1) phase in cell cycle, increasing tetraploidy, presumably because of cells escaping from abnormal mitosis in PC-3 cells. Consistently, overexpression of HN1 reversed the cell-cycle-specific observations, resulted in accumulation of cells in G(2)/M, and reduced the proliferation rate, which were investigated using flow cytometry and methylthiazol tetrazolium assays. As activating mutations of β-catenin have been demonstrated in late-stage tumors, and β-catenin stabilization was correlated with poor prognosis in previous reports, epidermal growth factor-upregulated HN1 expression might have a role in deregulating the AKT-GSK3β((S9))-mediated signaling as a novel compensating mechanism.     

Screening for fungal antagonists to control black mold disease and to induce the accumulation of antifungal compounds in onion after seed treatment

Twelve isolates belonging to the genera Aspergillus, Penicillium, and Trichoderma, from onion (Allium cepa L.)-growing soils were recently found to have antagonistic features against Aspergillus niger (An) van Tieghem, the cause of black mold disease of onion, in dual culture. In the work reported in this paper, the function of these isolates applied as seed treatment on onion seed germination was investigated. In addition, isolates with no negative effect on seeds were screened for their effect on shoot length, and for their abilities to inhibit colonization of An on seeds, to control black mold disease, to increase set bulb diameter, and to induce production of antifungal compounds in pot-grown onion sets. Application of non-aflatoxigenic A. flavus Link (AS3), T. harzianum Rifai (TRIC7) and (TRIC8) to seeds led to defense reactions with accumulation of antifungal compounds in sets, combined with increased protection against the disease, although they did not enhance bulb diameter.     

Increased concentration of polyvalent phospholipids in the adsorption domain of a charged protein

We studied the adsorption of a charged protein onto an oppositely charged membrane, composed of mobile phospholipids of differing valence, using a statistical-thermodynamical approach. A two-block model was employed, one block corresponding to the protein-affected region on the membrane, referred to as the adsorption domain, and the other to the unaffected remainder of the membrane. We calculated the protein-induced lipid rearrangement in the adsorption domain as arising from the interplay between the electrostatic interactions in the system and the mixing entropy of the lipids. Equating the electrochemical potentials of the lipids in the two blocks yields an expression for the relations among the various lipid fractions in the adsorption domain, indicating a sensitive dependence of lipid fraction on valence. This expression is a result of the two-block picture but does not depend on further details of the protein-membrane interaction. We subsequently calculated the lipid fractions themselves using the Poisson-Boltzmann theory. We examined the dependence of lipid enrichment, i.e., the ratio between the lipid fractions inside and outside the adsorption domain, on various parameters such as ionic strength and lipid valence. Maximum enrichment was found for lipid valence in the range between -3 and -4 in physiological conditions. Our results are in qualitative agreement with recent experimental studies on the interactions between peptides having a domain of basic residues and membranes containing a small fraction of the polyvalent phosphatidylinositol 4,5-bisphosphate (PIP2). This study provides theoretical support for the suggestion that proteins adsorbed onto membranes through a cluster of basic residues may sequester PIP2 and other polyvalent lipids.     

Interaction of bacteriophage lambda with its cell surface receptor: an in vitro study of binding of the viral tail protein gpJ to LamB (Maltoporin)

The cell surface receptor for bacteriophage Lambda is LamB (maltoporin). Responsible for phage binding to LamB is the C-terminal part, gpJ, of phage tail protein J. To study the interaction between LamB and gpJ, a chimera protein composed of maltose binding protein (MBP or MalE) connected to the C-terminal part of J (gpJ, amino acids 684-1131) of phage tail protein J of bacteriophage Lambda was expressed in Escherichia coli and purified to homogeneity. The interaction of the MBP-gpJ chimera protein with reconstituted LamB and its mutants LamB Y118G and the loop deletion mutant LamB Delta4+Delta6+Delta9v was studied using planar lipid bilayer membranes on a single-channel and multichannel level. Titration with the MBP-gpJ chimera blocked completely the ion current through reconstituted LamB when it was added to the cis side, the extracellular side of LamB with a half-saturation constant of approximately 6 nM in 1 M KCl. Control experiments with LamB Delta4+Delta6+Delta9v from which all major external loops had been removed showed similar blocking, whereas MBP alone caused no visible effect. Direct conductance measurement with His(6)-gpJ that contained a hexahistidyl tag (His(6) tag) at the N-terminal end of the protein for easy purification revealed no blocking of the ion current, requiring other measurements for the binding constant. However, when maltoporin was preincubated with His-gpJ, MBP-gpJ could not block the channel, which indicated that also His(6)-gpJ bound to the channel. High-molecular mass bands on SDS-PAGE and Western blots, confirming the planar lipid bilayer experiment results, also demonstrated stable complex formation between His(6)-gpJ and LamB or LamB mutants. The results revealed that phage Lambda binding includes not only the extracellular loops.