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Open access

Suleyman Aydin, Sebnem Erenler and Yalcin Kendir

Effects of Sodium Octanoate, Acylated Ghrelin, and Desacylated Ghrelin on the Growth of Genetically Engineered Escherichia Coli

Acylated ghrelin is a 28-amino acid peptide hormone bearing a fatty acid group based on octanoic acid (caprylic acid) at the serine which is located at position 3 and at the N-terminus. If this fatty acid is cleaved from acylated ghrelin, the remaining peptide is referred to as desacylated ghrelin. Free fatty acids (FFAs) can kill or inhibit the growth of bacteria. The purpose of this study was to test this ability using acylated ghrelin, desacylated ghrelin, and sodium octanoate (caprylic acid) as carbon sources for the genetically engineered Escherichia coli strains MK79 and MK57. For this experimental work, minimal medium was modified by replacing glucose with equal concentrations of acylated ghrelin, desacylated ghrelin, or sodium octanoate. Bacterial optical density, viability, alpha-amylase production, plasmid stability and pH of the growth medium were measured during these experiments. The media that allowed most growth, based on viable cell counts and the OD600 of MK79, was minimal medium, followed by the medium containing desacylated ghrelin or acylated ghrelin, and finally the medium containing sodium octanoate. The same order was observed for MK57. Neither of the strains lost plasmids during the entire course of each experiment. There was also little change in the pH of any of the media used for both strains. These results suggest that sodium octanoate, acylated ghrelin, and desacylated ghrelin, when compared with minimal medium, inhibit Escherichia coli growth. Proliferation was lowest when sodium octanoate was used as the carbon source, followed by acylated ghrelin and desacylated ghrelin. Therefore, the acylated ghrelin found previously in human saliva might help to inhibit pathogenic microorganisms, and acylated ghrelin levels below a critical concentration in saliva could result in an increased risk of oral infection.

Open access

Suleyman Aydin, Suna Aydin, Gerry Croteau, Íbrahim Sahin and Cihan Citil

Ghrelin, Nitrite and Paraoxonase/Arylesterase Concentrations in Cement Plant Workers

Occupational cement dust exposure has been associated with an increased risk of liver abnormalities, pulmonary disorders, and carcinogenesis. Decreased antioxidant capacity and increased plasma lipid peroxidation have been posed as possible causal mechanisms of disease. Accordingly, this study examined the serum paraoxonase (PON1) arylesterase (AE), ghrelin, HDL-C, LDL-C and serum nitrite (NOx) levels in cement dust exposed workers. Twenty-eight volunteer male cement plant workers and 30 volunteer control male workers, aged 29-54 years, participated. The concentrations of serum PON1, AE, NOx, ghrelin, and HDL-cholesterol and LDL-cholesterol were measured in both groups. PON-1, AE, ghrelin and HDL-cholesterol were lower in the cement plant workers than in controls. Serum nitrite (NOx), and LDL-C levels in cement plant workers were higher (p<0.05) than in the control group workers. No correlation was observed between the serum levels of HDL-cholesterol and PON1 and between HDL-cholesterol and ghrelin. A weak negative correlation was detected between the serum ghrelin and NOx. The study results strongly suggest that HDL-paraoxonase, AE, ghrelin, HDL-C, and high NOx, and LDL-C levels may have a role in disease involving oxidative damage. However, some studies are necessary to address the association between occupational dust exposure and respiratory symptoms.

Open access

Suleyman Aydin, İbrahim Sahin, Suna Aydin, Aziz Aksoy and Cihan Citil

The Past and Present of Paraoxonase Enzyme: Its Role in the Cardiovascular System and Some Diseases

Although paraoxonase is synthesized in many tissues including the heart, colon, kidneys, lungs, small intestines and brain, its major locus of synthesis is the liver. PON1 is in close association with apolipoproteins and protects LDL against oxidation. It was reported that PON1 quantities dropped to 40 times lower than normal in cardiovascular diseases and diseases like diabetes, ulcerative colitis, Crohn's disease, chronic renal failure, SLE, Behcet's disease, cancer, hepatitis B, obesity, metabolic syndrome, Alzheimer's and dementia. It is speculated that the concerning decline in serum PON1 amount results from single nucleotide polymorphism in the coding (Q192R, L55M) and promoter (T-108C) sites of the PON1 gene. Additionally, circulating amounts of PON1 are affected by vitamins, antioxidants, fatty acids, dietary factors, drugs, age and lifestyle. This collection attempts to review and examine the past and present studies of paraoxonase and its relation with the cardiovascular system and some relevant diseases.

Open access

Ahmet Erensoy, Suleyman Aydin, Neslihan Kelestimur, Sevda Kirbag and Salih Kuk

The Change of Ghrelin Levels in Intestinal Parasitic Infections

The aim of this work was to examine the relationship between active (acylated ghrelin) and inactive (desacylated ghrelin) ghrelin in the serum and other serum parameters in intestinal parasitic infections and healthy controls. Conventional microscopic methods (saline and iodine solutions, trichrome stain) were used to identify intestinal parasites in stool samples of 29 subjects attending Firat University Hospital. Serum parameters were assessed in a single measurement of serum from 29 parasite subjects, and in 18 healthy controls. Serum acylated ghrelin and desacylated ghrelin levels were measured using a commercial radioimmunoassay (RIA) kit. Paraoxonase and arylesterase were measured by using a spectrophotometer at 405 nm and 270 nm, respectively. Serum concentrations of acylated ghrelin and desacylated ghrelin were more markedly decreased in helminth bearing patients than the control group. Glucose, cholesterol and triglyceride levels were higher in intestinal parasitic infections than in controls. Furthermore, there were no correlations between ghrelin levels and BMI. These results indicate that low ghrelin and PON1/AE level may be important for appetite monitoring in intestinal parasitic infections.

Open access

Zekiye Catak, Esra Kocdemir, Kader Ugur, Meltem Yardim, İbrahim Sahin, Hilal Kaya and Suleyman Aydin



Schizophrenia, particularly the form related to excessive dopamine (DA), is a chronic psychotic disorder affecting millions of people worldwide. Renalase metabolizes its catecholamine (CA) substrates, including DA, suggesting that there might be an association between renalase levels and schizophrenia occurrence. Therefore, the current study aimed to evaluate the renalase and CA levels in the serum of patients with schizophrenia.


The study was conducted with thirty-three schizophrenia patients and an age- and gender-matched group of thirty-one controls. Renalase and CA levels were measured by using an enzyme-linked immunosorbent assay (ELISA).


Renalase levels were significantly lower in the schizophrenia patients than in the control group (p<0.05), whereas DA levels were significantly higher (p<0.05). The epinephrine (Epi) levels of both groups were similar (p=0.186), while the norepinephrine levels in patients with schizophrenia were significantly lower than those in the control group (p<0.05). The areas under the curves for the renalase-dopamine, renalase-norepinephrine and renalase-epinephrine ratios were 0.805, 95% confidence interval (CI): 0.699–0.912 (p<0.001); 0.726, 95% CI: 0.594–0.859 (p=0.032); and 0.656, 95% CI: 0.520–0.791 (p=0.02).


The high DA levels in patients with schizophrenia might be due to low renalase levels. Renalase enzyme levels may play a substantial role in the pathophysiology of schizophrenia. Thus, this enzyme might be a new future target for the treatment and diagnosis of schizophrenia after intrabrain renalase and DA dynamics have been further evaluated.