Evaluation of biotoxins and toxic metal risks in mussels from the Sea of Marmara following marine mucilage.

The mucilage phenomenon observed in the Sea of Marmara in 2021, has raised public concern about seafood safety. Mediterranean mussels serve as a vehicle in food chain, enabling the transfer of pollutants. Farmed and wild mussels were collected from 4 different stations throughout the fishing season. Biotoxins causing amnesic, paralytic, or diarrhetic shellfish poisonings (ASP, PSP, or DSP) were examined during monthly samplings. Potential health risks posed by cadmium, lead and arsenic were assessed. Health risks were evaluated considering 150 g/week mussel consumption, accounting for the different age groups of consumers (50, 60, 70 kg). Estimated Weekly Intake calculations of metals were determined to be lower than Provisional Tolerable Weekly Intake at all age groups throughout the sampling period in all stations. Target Hazard QuotientCd of mussels captured from Istanbul Strait was always determined <1, while it was equal to 1 for 50 kg individuals in Gelibolu samples. All THQAs were >1. Target carcinogenic Risk was evaluated for Pb and iAs, which were found to be negligible and acceptable, respectively. No biotoxins responsible for ASP, PSP, or DSP were detected. Hg levels were under detectable limits. Excluding Cd, the results did not reveal any risks associated with mussel consumption during mucilage.

Blocking SIG1R Along with Low Cadmium Exposure Display Anti-cancer Qualities in Both MCF7 and MDA-MB-231 Cells.

Sigma-1 receptor (SIG1R) is a chaperone that modulates inositol 1,4,5-trisphosphate receptor type1 (IP3R1) calcium (Ca2+) channels on the endoplasmic reticulum. Therefore, SIG1R functions as an indirect regulator of Ca2+ and acts as an apoptosis modulator. Increased expression of SIG1R is associated with poor prognosis in breast cancers (BC), and SIG1R antagonists like BD1047 induce apoptosis. As a heavy metal, cadmium (Cd2+) is competitive with Ca2+ due to its physicochemical similarities and may trigger apoptosis at low concentrations. Our study investigated the SIG1R protein expression in 74 BC patients and found a significant increase in SIG1R expression in the triple-negative BC subtype. We also examined the apoptotic and anti-cancer effects of BD1047 in combination with CdCl2 in MCF7 and MDA-MB-213 cells. Cells were treated with CdCl2 at doses of 1 µM, 25 µM, and 50 µM, along with BD1047. Higher doses of CdCl2 were cytotoxic on both cancer cells and significantly increased DNA breaks. However, low-dose CdCl2 with BD1047 increased cell death and the apoptotic index in BC cells, although it did not exhibit cytotoxic effects on HUVEC cells. Co-administration of low-dose CdCl2 with BD1047 also reduced the migration and colony-forming ability of BC cells. Moreover, the expression of SIG1R protein in these groups decreased significantly compared to groups treated with BD1047 or low-dose CdCl2 alone. In conclusion, low-dose CdCl2 is thought to increase the apoptotic ability of BD1047 in BC cells by reducing SIG1R expression.

Assessment of health risks due to toxic metals in demersal fish captured from Saros and Edremit Bays, Northern Aegean Sea.

Bays are vulnerable ecosystems generally located near densely populated areas where toxic metals tend to accumulate and stay longer, affecting marine life. This study aimed to investigate the age-based health risks arising from Hg, Cd, Pb, and As in demersal fish captured from two major bays in the Aegean Sea. For this purpose, red mullet, whiting, piper gurnard, and tub gurnard, frequently consumed species, were caught from Saros and Edremit Bays. Toxic metal concentrations were determined from the muscle tissue of fish. Health risk assessments were conducted by the estimation of weekly intake (EWI), provisional tolerable weekly intake (PTWI), target hazard quotient (THQ), total THQ (TTHQ), and target carcinogenic risk (TR). Red mullet from Edremit Bay was the species with the highest toxic metal levels, which were 1.597 mg/kg, 0.041 mg/kg, 0.070 mg/kg, and 19.351 mg/kg for Hg, Cd, Pb, and As, respectively. Whiting from Edremit Bay had higher mean concentrations of Hg and As than those from Saros Bay. The levels of Hg, Pb, and As (0.328, 0.043, and 0.574 mg/kg) in the tub gurnard were higher in comparison with the piper gurnard (0.252, 0.020, and 0.382 mg/kg) caught in the same station in Saros. TTHQs of red mullet and whiting from the same bay were found to be > 1, indicating potential health risks for all nine age categories studied. On the other hand, TTHQs of all species from Saros Bay were determined to be > 1 for the first four age categories, which might trigger health risks for children and adolescents. According to the TR index for Pb, no risk was determined for the fish from both bays. However, TR calculations for inorganic As indicated high cancer risk in most of the age categories for red mullet and whiting from Edremit Bay. To sum up, the results revealed that the fish captured from Edremit Bay posed serious health risks in terms of Hg and As concentrations for all nine age categories. Surveillance and monitoring of toxic metal levels in demersal fish and population-based health risk evaluation are vital in heavily populated bays.

Clinicopathological Factors Affecting Mucin 1, Mucin 2, and Mucin 5AC Staining in Patients who Underwent Resection for Colorectal Cancer.

OBJECTIVE: To investigate the clinicopathological factors affecting mucins (MUC 1, MUC 2, and MUC 5AC) staining in patients who underwent resection for colorectal cancer. STUDY DESIGN: An observational study. Place and Duration of the Study: Department of General Surgery and Department of Pathology, Kafkas University Faculty of Medicine, Kars, Turkey, between January 2020 and January 2021. METHODOLOGY: Patients operated on for colorectal adenocarcinoma were included in the study. Patients who underwent colorectal surgery for benign diseases or had a pathological diagnosis other than adenocarcinoma were excluded from the study. Clinicopathological factors affecting MUC1, MUC2, and MUC5AC staining were evaluated with appropriate statistical tests, assuming a significant p-value of less than 0.05. RESULTS: Of the 30 patients who met all study criteria, 18 (60%) were males. The mean age of all patients was 62.83±16.79 (21-88). MUC1 strongly positive staining was observed in 18 (60%) cases, and high expression was detected in pT4 and pT3 cases (p=0.005). In addition, increased expression was also noted in cases with lymph node involvement (p=0.045). MUC2 expression was more than 60% (strongly positive) in 20 (66.7%). The MUC2 expression was increased in moderately differentiated cases (p=0.032). There was no staining (negativity) in 22 (73.3%) cases with MUC5AC, and more than 60% staining (strongly positive) was observed in 3 (10%) cases. In addition, strong expression was noted in rectosigmoid tumours (p=0.001), female patients (p=0.046), and patients with pT3 and pT4 tumours (p=0.05). CONCLUSION: High MUC1 and high MUC5AC staining were observed in advanced colorectal cancer, whereas high MUC2 staining was observed in patients with moderate tumour differentiation. KEY WORDS: Colorectal cancers, Gene expressions, Mucin.

Protective Effects of Betanin against Oxidative Stress in a Peripheral Artery Vasospasm Model in Rat.

Objective: The aim of this study is to determine protective/modulatory effects of betanin in a femoral artery vasospasm model in rats. Materials and Methods: Sprague-Dawley rats were divided into three groups. Group 1: sham (n = 7), group 2: vasospasm model only (n = 7), group 3: postoperative betanin treatment in the vasospasm model (n = 7). 100 mg/kg betanin was administered orally to group 3 for 7 days, postoperatively. Peripheral blood malondialdehyde (MDA) and nitric oxide (NO) levels were measured for the quantification of oxidative stress, lumen diameter and wall thickness of femoral artery segments were determined to assess vasodilator effects of betanin. Results: Femoral artery vasospasm formation significantly increased both MDA (13.54 ± 3.09 mmol/mL) and NO levels (0.61 ± 0.06 µmol/mL) relative to the sham (9.07 ± 1.09 and 0.48 ± 0.1, respectively). Upon betanin administration, both MDA and NO approached baseline levels (9.95 ± 0.92 and 0.5 ± 0.06, respectively). Pathological examination of lumen diameter and wall thickness of the femoral arteries also revealed that betanin administration resulted in significant increase in lumen diameter when compared to vasospasm group (614.15 ± 245.77 versus 117.40 ± 46.19 µm) and decrease in wall thickness (64.68 ± 14.13 versus 96.73 ± 9.20 µm). Conclusion: Betanin was shown to have protective effect against oxidative stress in a peripheral artery vasospasm model in rats. It may also have a role in mitigating maladaptive changes in arterial structure, as shown in pathological examination.

The protective effect of betanin and copper on spinal cord ischemia-reperfusion injury.

Context: Both copper and betanin have been implicated as having significant bioactivity against ischemic damage in a variety of experimental and clinical settings. The aim of this study is to investigate whether betanin and copper have any protective effect on spinal cord in an ischemia-reperfusion (I/R) model in rats.Design: Spraque-Dawley rats were used in four groups: Sham group (n = 7), control group (laparotomy and cross-clamping of aorta, n = 7), betanin treatment group (dosage of 100 mg/kg of betanin administered intraperitoneally (i.p.) 60 min before laparotomy, n = 7), copper sulfate treatment group (administered copper sulfate i.p. at a dose of 0.1 mg/kg/day for 7 days before laparotomy, n = 7). Malondialdehyde (MDA), glutathione (GSH) levels, myeloperoxidase (MPO) and superoxide dismutase (SOD) activity were measured. Terminal deoxynucleotidyl transferase (TdT) dUTP Nick-End Labeling (TUNEL) assay was also performed to evaluate apoptosis.Setting: Kafkas University, Faculty of Medicine, Kars, Turkey.Results: I/R injury was successfully demonstrated with the surgical model. Betanin and copper treatment significantly decreased MDA levels, MPO activity and the number of apoptotic cells in the spinal cord. Betanin and copper treatment significantly increased GSH levels. Copper treatment significantly increased SOD activity, whereas betanin was not as effective. Apoptotic cells were significantly decreased in both treatment groups.Conclusion: I/R injury of the spinal cord can be successfully demonstrated by aortic clamping in this surgical model. Betanin/Copper sulphate has ameliorative effects against operative I/R injury. Low toxicity of those agents makes them ideal targets for clinical research for this purpose.

Boric acid and Borax Supplementation Reduces Weight Gain in Overweight Rats and Alter L-Carnitine and IGF-I Levels.

The aim of this study was to investigate the effects of boric acid (BA) and borax (BX) on live weight and obesity associated molecules including leptin, L-carnitine, insulin-like growth factor 1 (IGF-I), and heat shock proteins 70 (HSP70) in rats fed with high-fat diet. A total of 60 rats were equally allocated as ND (normal diet), HF (high-fat diet), HF+BA, HF+BX, ND+BX, ND+BA. Body weight increases in HF+BA (85 g) and HF+BX (86 g) were significantly lower (p<0.05) compared to HF group (126 g). Boron treatment decreased serum L-carnitine level in high-fat diet (HF+BA 11.12 mg/L, HF+BX 10.51 mg/L, p<0.05) compared to HF group (15.57 mg/L), while no change was observed in groups ND+BA (7.55 mg/L) and ND+BX (7.57 mg/L) compared to group ND (8.29 mg/L). Neither BA nor BX supplementation in ND and HF groups altered the serum levels of HSP70 and leptin. BA and BX supplementation in rats fed HF resulted in a significant reduction in live weight. Boron compounds altered L-carnitine and IGF-1 levels in rats. These results indicate that boron compounds are beneficial in the treatment of obesity as well as in the prevention of high-fat diet-induced weight increase. Alterations in serum L-carnitine and IGF-1 levels in boron treated rats also indicate possible role of boron compounds in energy metabolism in response to high fat diet.

The protective role of jervine against radiation-induced gastrointestinal toxicity.

In this study, we investigated whether jervine (J) could prevent gastrointestinal (GI) side effects of abdominopelvic radiotherapy (RT) in Wistar-Albino female rats. Rats were divided into five groups: control (C), J only (J), J administered at 5 mg/kg/days for 7 days, RT only (RT), J before RT (J + RT), J administered for seven days before RT, J both before and after RT (J + RT + J), and J administered for 7 days before RT and after RT for 3 days. The weights of rats were measured on the 1st, 7th, and 10th days of the study. Rats were sacrificed to obtain tissues from the liver and intestine, which was followed by taking blood samples intracardially. In addition, the tissues were stained with pyruvate dehydrogenase (PDH) immunohistochemically. In our study, J supplementation markedly reduced weight loss, and histopathological, immunohistochemical, biochemical results suggest that J had a protective effect on GI toxicity following RT.

Expression profile and cellular localizations of mucin proteins, CK7, and cytoplasmic p27 in Barrett's esophagus and esophageal adenocarcinoma.

PURPOSE: Barrett's esophagus is one of the main risk factors for increased incidence of esophageal adenocarcinoma. In this study, we studied protein expression levels and cellular localizations of MUC-1, MUC-2, MUC-5AC, CK7, and cytoplasmic p27 to assess the relationship between the expression of each of these proteins and the disease progression on endoscopic biopsies. MATERIALS AND METHODS: Immunohistochemical analyses were performed using antibodies produced against MUC-1, MUC-2, MUC-5AC, CK7, and p27. Endoscopic specimens of esophageal mucosa were obtained from 72 patients who underwent esophagectomy for Barrett's esophagus, metaplasia, dysplasia, or esophageal adenocarcinoma developed from Barrett's esophagus. RESULTS: Multilayer squamous epithelium showed only MUC-1 positivity in the EAC group while MUC-2 and MUC-5AC staining could not be detected in this group. Strong and diffused membranous or cytoplasmic staining of CK7 was observed at squamous, ductal, surface columnar and/or glandular epithelium. c-p27 staining was diffused and moderate in the cellular membranes observed in all groups except for esophageal epithelial metaplasia without intestinal metaplasia. Additionally, weakly focal cytoplasmic staining in squamous epithelium of p27 in EAC was detected. CONCLUSIONS: Barrett's esophagus, which has a heterogeneous epithelium, might yield different diagnosis based on endoscopic evaluation and immunohistological investigation. Thus, the use of MUC1, p27, and CK7 might strengthen the truthful diagnosis. MUC-1, CK7, and c-p27 immunostaining can be used as the predictive markers for esophageal cancer progression from Barrett's esophagus.

Inhibition of Sirtuin 6 Induces Neuroblastoma Differentiation.

BACKGROUND/AIM: Sirtuins (SIRTs) play crucial roles in various signaling pathways that modulate differentiation and proliferation. We sought to elucidate the role of SIRTs in differentiation and proliferation of human neuroblastoma (NB). MATERIALS AND METHODS: NB cells were treated with nicotinamide (NAM), a non-specific SIRT inhibitor, SIRT-targeted short hairpin RNAs, and retinoic acid to assess cell growth and differentiation. RESULTS: SIRTs are involved in proliferation and differentiation using NAM in BE(2)-C cells. Specifically, SIRT6 knockdown in BE(2)-C cells reduced cell proliferation, induced neurite extension, corresponding with induction of p21CIP1 expression and G1 cell-cycle arrest. These effects were rescued by forced re-overexpression of SIRT6. SIRT6 expression was reduced in differentiated human NB sections, and RA-induced differentiation in BE(2)-C cells. CONCLUSION: SIRTs have important oncogenic properties in NB beyond its established functions in aging and genome stability. SIRT6 may represent a novel target for developing future therapeutics for the treatment of aggressive NBs.

Activin signaling is an essential component of the TGF-ß induced pro-metastatic phenotype in colorectal cancer.

Advanced colorectal cancer (CRC) remains a critical health care challenge worldwide. Various TGF-ß superfamily members are important in colorectal cancer metastasis, but their signaling effects and predictive value have only been assessed in isolation. Here, we examine cross-regulation and combined functions of the two most prominent TGF-ß superfamily members activin and TGF-ß in advanced colorectal cancer. In two clinical cohorts we observed by immune-based assay that combined serum and tissue activin and TGF-ß ligand levels predicts outcome in CRC patients and is superior to single ligand assessment. While TGF-ß growth suppression is independent of activin, TGF-ß treatment leads to increased activin secretion in colon cancer cells and TGF-ß induced cellular migration is dependent on activin, indicating pathway cross-regulation and functional interaction in vitro. mRNA expression of activin and TGF-ß pathway members were queried in silico using the TCGA data set. Coordinated ligand and receptor expression is common in solid tumors for activin and TGF-ß pathway members. In conclusion, activin and TGF-ß are strongly connected signaling pathways that are important in advanced CRC. Assessing activin and TGF-ß signaling as a unit yields important insights applicable to future diagnostic and therapeutic interventions.

NFkB is essential for activin-induced colorectal cancer migration via upregulation of PI3K-MDM2 pathway.

Colorectal cancer (CRC) remains a common and deadly cancer due to metastatic disease. Activin and TGFB (TGFß) signaling are growth suppressive pathways that exert non-canonical pro-metastatic effects late in CRC carcinogenesis. We have recently shown that activin downregulates p21 via ubiquitination and degradation associated with enhanced cellular migration independent of SMADs. To investigate the mechanism of metastatic activin signaling, we examined activated NFkB signaling and activin ligand expression in CRC patient samples and found a strong correlation. We hypothesize that activation of the E3 ubiquitin ligase MDM2 by NFkB leads to p21 degradation in response to activin treatment. To dissect the link between activin and pro-carcinogenic NFkB signaling and downstream targets, we found that activin but not TGFB induced activation of NFkB leading to increased MDM2 ubiquitin ligase via PI3K. Further, overexpression of wild type p65 NFkB increased MDM2 expression while the NFkB inhibitors NEMO-binding domain (NBD) and Bay11-7082 blocked the activin-induced increase in MDM2. In conclusion, in colon cancer cell migration, activin utilizes NFkB to induce MDM2 activity leading to the degradation of p21 in a PI3K dependent mechanism. This provides new mechanistic knowledge linking activin and NFkB signaling in advanced colon cancer which is applicable to targeted therapeutic interventions.

Distribution of OCPs and PCBs in Mussels (Mytilus galloprovincialis) from the Marmara Sea Coastal Sites.

Mussel samples were collected monthly between October-2010 and October-2011 from four stations (Bosphorus, Bandirma, Gelibolu, Tekirdag) in the Marmara Sea. Two consecutive months' samples were homogenized and combined as a single group for analysis. Mussel samples were analyzed for Organochlorine pesticides (OCPs); (total-DDT, total-HCH, Endrin, α-Endosulfan, ß-Endosulfan, Heptachlor) and Polychlorinated biphenyls (PCBs); (PCB 28, PCB 52, PCB 138, PCB 153, and PCB 180). All analyses were done according to Eurofins house method in ERGO Laboratory in Germany. Concentrations of α-endosulfan and heptachlor in mussel tissues were below method detection limits. The annual average OCPs concentrations among the stations ranged between 0.02 and 1.45 ng/g (wet weight), 1.9-99.75 ng/g (lipid weight) whereas the annual average PCBs concentrations among the stations ranged between 0.03 and 0.40 ng/g (wet weight), 1.71-26.48 ng/g (lipid weight), respectively. There was no relation between fat content of mussels and residues of the contaminants. PCB 138 and PCB 153 were the most predominant PCBs, while total-DDT and total-HCH were the most predominant OCPs in the mussels. Total-DDT concentrations were higher compared to total-HCH and PCBs isomers. Measured levels were below the national and international committees' and institutions' limits for human consumption and protection of aquatic biota.

SIRT2-Mediated Deacetylation and Tetramerization of Pyruvate Kinase Directs Glycolysis and Tumor Growth.

Sirtuins participate in sensing nutrient availability and directing metabolic activity to match energy needs with energy production and consumption. However, the pivotal targets for sirtuins in cancer are mainly unknown. In this study, we identify the M2 isoform of pyruvate kinase (PKM2) as a critical target of the sirtuin SIRT2 implicated in cancer. PKM2 directs the synthesis of pyruvate and acetyl-CoA, the latter of which is transported to mitochondria for use in the Krebs cycle to generate ATP. Enabled by a shotgun mass spectrometry analysis founded on tissue culture models, we identified a candidate SIRT2 deacetylation target at PKM2 lysine 305 (K305). Biochemical experiments including site-directed mutants that mimicked constitutive acetylation suggested that acetylation reduced PKM2 activity by preventing tetramerization to the active enzymatic form. Notably, ectopic overexpression of a deacetylated PKM2 mutant in Sirt2-deficient mammary tumor cells altered glucose metabolism and inhibited malignant growth. Taken together, our results argued that loss of SIRT2 function in cancer cells reprograms their glycolytic metabolism via PKM2 regulation, partially explaining the tumor-permissive phenotype of mice lacking Sirt2 Cancer Res; 76(13); 3802-12. ©2016 AACR.

Expression of an Oncogenic BARD1 Splice Variant Impairs Homologous Recombination and Predicts Response to PARP-1 Inhibitor Therapy in Colon Cancer.

BRCA1-associated RING domain protein 1 (BARD1) stabilizes BRCA1 protein by forming a heterodimeric RING-RING complex, and impacts function of BRCA1, including homologous recombination (HR) repair. Although colon cancer cells usually express wild type BRCA1, presence of an oncogenic BARD1 splice variant (SV) in select cancers may render BRCA1 dysfunctional and allow cells to become sensitive to HR targeting therapies. We previously reported association of loss of full-length (FL) BARD1 with poor prognosis in colon cancer as well as expression of various BARD1 SVs with unknown function. Here we show that loss of BARD1 function through the expression of a BARD1 SV, BARD1ß, results in a more malignant phenotype with decreased RAD51 foci formation, reduced BRCA1 E3 ubiquitin ligase activity, and decreased nuclear BRCA1 protein localization. BARD1ß sensitizes colon cancer cells to poly ADP ribose polymerase 1 (PARP-1) inhibition even in a FL BRCA1 background. These results suggest that expression of BARD1ß may serve as a future biomarker to assess suitability of colon cancers for HR targeting with PARP-1 inhibitors in treatment of advanced colon cancer.

Activin and TGFß use diverging mitogenic signaling in advanced colon cancer.

BACKGROUND: Understanding cell signaling pathways that contribute to metastatic colon cancer is critical to risk stratification in the era of personalized therapeutics. Here, we dissect the unique involvement of mitogenic pathways in a TGFß or activin-induced metastatic phenotype of colon cancer. METHOD: Mitogenic signaling/growth factor receptor status and p21 localization were correlated in primary colon cancers and intestinal tumors from either AOM/DSS treated ACVR2A (activin receptor 2) -/- or wild type mice. Colon cancer cell lines (+/- SMAD4) were interrogated for ligand-induced PI3K and MEK/ERK pathway activation and downstream protein/phospho-isoform expression/association after knockdown and pharmacologic inhibition of pathway members. EMT was assessed using epithelial/mesenchymal markers and migration assays. RESULTS: In primary colon cancers, loss of nuclear p21 correlated with upstream activation of activin/PI3K while nuclear p21 expression was associated with TGFß/MEK/ERK pathway activation. Activin, but not TGFß, led to PI3K activation via interaction of ACVR1B and p85 independent of SMAD4, resulting in p21 downregulation. In contrast, TGFß increased p21 via MEK/ERK pathway through a SMAD4-dependent mechanism. While activin induced EMT via PI3K, TGFß induced EMT via MEK/ERK activation. In vivo, loss of ACVR2A resulted in loss of pAkt, consistent with activin-dependent PI3K signaling. CONCLUSION: Although activin and TGFß share growth suppressive SMAD signaling in colon cancer, they diverge in their SMAD4-independent pro-migratory signaling utilizing distinct mitogenic signaling pathways that affect EMT. p21 localization in colon cancer may determine a dominant activin versus TGFß ligand signaling phenotype warranting further validation as a therapeutic biomarker prior to targeting TGFß family receptors.

SIRT3 deacetylates and increases pyruvate dehydrogenase activity in cancer cells.

Pyruvate dehydrogenase E1α (PDHA1) is the first component enzyme of the pyruvate dehydrogenase (PDH) complex that transforms pyruvate, via pyruvate decarboxylation, into acetyl-CoA that is subsequently used by both the citric acid cycle and oxidative phosphorylation to generate ATP. As such, PDH links glycolysis and oxidative phosphorylation in normal as well as cancer cells. Herein we report that SIRT3 interacts with PDHA1 and directs its enzymatic activity via changes in protein acetylation. SIRT3 deacetylates PDHA1 lysine 321 (K321), and a PDHA1 mutant mimicking a deacetylated lysine (PDHA1(K321R)) increases PDH activity, compared to the K321 acetylation mimic (PDHA1(K321Q)) or wild-type PDHA1. Finally, PDHA1(K321Q) exhibited a more transformed in vitro cellular phenotype compared to PDHA1(K321R). These results suggest that the acetylation of PDHA1 provides another layer of enzymatic regulation, in addition to phosphorylation, involving a reversible acetyllysine, suggesting that the acetylome, as well as the kinome, links glycolysis to respiration.

Monitoring programme on toxic metal in bluefish (Pomatomus saltatrix), anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus) from Istanbul, Turkey: levels and estimated weekly intake.

Toxic metal (Hg, Cd, Pb, Cu and Zn) concentrations of small-medium bluefish, anchovy and sardine in Istanbul, Turkey, were determined using inductively coupled plasma-mass spectrometry (ICP-MS) throughout 1 year. The concentrations of pollutants were found to vary according to season and species. Estimates of weekly intake levels of the metals were calculated and compared to recommended safe limits for fish consumption by humans. The levels of Cd, Pb, Cu and Zn in the fillets of all species resulted in estimates of weekly intake levels that were lower than the recommended safe limits. The concentrations of Hg of small bluefish in September, of medium bluefish in June and September, of anchovy in March, and of sardine in August and September resulted in estimates of weekly intake levels that were higher than the recommended safe limits for human consumption.

SIRT2 is a tumor suppressor that connects aging, acetylome, cell cycle signaling, and carcinogenesis.

One long standing observation in clinical oncology is that age increase is the single most statistically significant factor/variable that predicts for the incidence of solid tumors. This observation suggests that the cellular and molecular processes and mechanisms that direct an organism's life span may be used to determine the clinical connection between aging and carcinogenesis. In this regard, the genes that impact upon longevity have been characterized in S. cerevisiae and C. elegans, and the human homologs include the Sirtuin family of protein deacetylases. We have recently shown that the primary cytoplasmic sirtuin, Sirt2 appears to meet the criteria as a legitimate tumor suppressor protein. Mice genetically altered to delete Sirt2 develop gender-specific tumorigenesis, with females primarily developing mammary tumors, and males developing multiple different types of gastrointestinal malignancies. Furthermore human tumors, as compared to normal samples, displayed significant decreases in SIRT2 levels suggesting that SIRT2 may also be a human tumor suppressor.

Exploring the electrostatic repulsion model in the role of Sirt3 in directing MnSOD acetylation status and enzymatic activity.

Mitochondrial oxidative metabolism is the major site of ATP production as well as a significant source of reactive oxygen species (ROS) that can cause damage to critical biomolecules. It is well known that mitochondrial enzymes that scavenge ROS are targeted by stress responsive proteins to maintain the fidelity of mitochondrial function. Manganese superoxide dismutase (MnSOD) is a primary mitochondrial ROS scavenging enzyme, and in 1983 Irwin Fridovich proposed an elegant chemical mechanism/model whereby acetylation directs MnSOD enzymatic activity. He christened it the "electrostatic repulsion model." However, the biochemical and genetic mechanism(s) determining how acetylation directs activity and the reasons behind the evolutionarily conserved need for several layers of transcriptional and posttranslational MnSOD regulation remain unknown. In this regard, we and others have shown that MnSOD is regulated, at least in part, by the deacetylation of specific conserved lysines in a reaction catalyzed by the mitochondrial sirtuin, Sirt3. We speculate that the regulation of MnSOD activity by lysine acetylation via an electrostatic repulsion mechanism is a conserved and critical aspect of MnSOD regulation necessary to maintain mitochondrial homeostasis.