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Öğe Determination of alpha-2,6 sialic acid in developmental stages of Galleria mellonella (Lepidoptera)(Int Science Services/Balaban Publishers, 2009) Saribek, Buget; Erden, Secil; Karacali, SabireSialic acids are the terminal glycan structures of many glycoproteins and glycolipids, and they play a key role in many biological processes. Sialic acids can be classified according to their linkages to underlying glycans as alpha-2,3-, alpha-2,6-, and alpha-2,8 sialic acids. In this study, the expression level and distribution of alpha-2,6 linked sialic acid in the third and final larval, mature prepupa, and pupa stages of Galleria mellonella were investigated by SNA (Sambucus nigra agglutinin) lectin immunofluorescence and lectin blot analysis. The immunofluorescence analysis showed that levels of alpha-2,6 linked sialic acid were high in larval stages, especially the last larval stage, lower in mature prepupa and absent in pupa. The results of lectin blotting with SNA were consistent with immunofluorescence results. From these results, it could be inferred that the level of alpha-2,6 linked terminal sialic acid in insect tissues declines during development and aging.Öğe Determination of alpha-2,6 sialic acid in developmental stages of Galleria mellonella (Lepidoptera)(Int Science Services/Balaban Publishers, 2009) Saribek, Buget; Erden, Secil; Karacali, SabireSialic acids are the terminal glycan structures of many glycoproteins and glycolipids, and they play a key role in many biological processes. Sialic acids can be classified according to their linkages to underlying glycans as alpha-2,3-, alpha-2,6-, and alpha-2,8 sialic acids. In this study, the expression level and distribution of alpha-2,6 linked sialic acid in the third and final larval, mature prepupa, and pupa stages of Galleria mellonella were investigated by SNA (Sambucus nigra agglutinin) lectin immunofluorescence and lectin blot analysis. The immunofluorescence analysis showed that levels of alpha-2,6 linked sialic acid were high in larval stages, especially the last larval stage, lower in mature prepupa and absent in pupa. The results of lectin blotting with SNA were consistent with immunofluorescence results. From these results, it could be inferred that the level of alpha-2,6 linked terminal sialic acid in insect tissues declines during development and aging.Öğe The Determination of N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc) Types of Sialic Acids in Hematopoietic Organ of The Silkworm, Bombyx mori L. (Lepidoptera: Bombycidae)(Kafkas Univ, Veteriner Fakultesi Dergisi, 2012) Izzetoglu, Savas; Karacali, SabireIn insects, for a long time, it was generally accepted that members of insect do not have sialic acids which are typical terminal glycans of cells surface glycolipids and glycoproteins, and thus especially important in cell interactions and signaling events. Here, it was reported the occurrence of sialic acid known the most common in all organisms (Neu5Ac and Neu5Gc) in hematopoietic organ of larvae of the silkworm, Bombyx mori. Histochemical and cytochemical analysis of hematopoietic organ sections with the FITC- and Gold-conjugated lectins (Limulus polyphemus, LPA) showed the presence of sialic acids in hematopoietic organ. The results provide further evidence for the existence of sialic acids in insects.Öğe Determination of sialic acids in the nervous system of silkworm (Bombyx mori L.): effects of aging and development(Inst Bioloska Istrazivanja Sinisa Stankovic, 2017) Soya, Seckin; Sahar, Umut; Yikilmaz, Mehmet Salih; Karacali, SabireSialic acids mainly occur as components on cell surface glycoproteins and glycolipids. They play a major role in the chemical and biological diversity of glycoconjugates. Although sialic acids exhibit great structural variability in vertebrates, glycoconjugates with sialic acids have also been determined in small amounts in invertebrates. It has been suggested that sialic acids play important roles in the development and function of the nervous system. Despite Bombyx mori being a model organism for the investigation of many physiological processes, sialic acid changes in its nervous system have not been examined during development and aging. Therefore, in this study we aimed to determine sialic acid changes in the nervous system of Bombyx mori during development and aging processes. Liquid chromatography-mass spectrometry (LC-MS) and lectin immunohistochemistry were carried out in order to find variations among different developmental stages. Developmental stages were selected as 3rd instar (the youngest) and 5th larval instar (young), motionless prepupa (the oldest) and 13-day-old pupa (adult development). At all stages, only Neu5Ac was present, however, it dramatically decreased during the developmental and aging stages. On the other hand, an increase was observed in the amount of Neu5Ac during the pupal stage. In immunohistochemistry experiments with Maackia amurensis agglutinin (MAA) and Sambucus nigra agglutinin (SNA) lectins, the obtained staining was consistent with the obtainedLC-MS results. These findings indicate that sialic acids are abundant at the younger stages but that they decrease in the insect nervous system during development and aging, similarly as in mammals.Öğe Genetic Characterization of Toxoplasma gondii Isolates and Toxoplasmosis Seroprevalence in Stray Cats of Izmir, Turkey(Public Library Science, 2014) Can, Huseyin; Doskaya, Mert; Ajzenberg, Daniel; Ozdemir, H. Gokhan; Caner, Ayse; Iz, Sultan Gulce; Doskaya, Aysu Degirmenci; Atalay, Esra; Cetinkaya, Cagdas; Urgen, Saygun; Karacali, Sabire; Un, Cemal; Darde, Marie-Laure; Guruz, YukselCurrently, some Toxoplasma gondii genotypes are being associated with serious clinical presentations. A recent report showing the Africa 1 genotype in two local congenital toxoplasmosis cases acquired in Turkey formed the basis of this study because atypical Africa 1 genotype is most frequently detected in animals and patients from sub-Saharan Africa. Since stray cats are considered as the linkage between wild life and urban life in T. gondii transmission, the present study aimed to isolate and characterize T. gondii strains circulating in stray cats of Izmir (Western Turkey). A secondary objective was to determine toxoplasmosis seroprevalence in this cat population. Tissues obtained from 100 deceased stray cats were bioassayed and isolated strains were genotyped using 15 microsatellite markers. In addition, toxoplasmosis seroprevalence was analyzed in 1121 cat sera collected from several large veterinary clinics in Izmir. Among the 22 isolates, 19 were Type II (86.3%), two were Type III (9%) and one was Africa 1 genotype (4.5%). The overall seropositivity rates in cats were 42-48% and 33.4-34.4% according to IFA and ELISA, respectively. Seroprevalence in deceased cats was significantly higher than in healthy cats (P = 0.0033). Finding both the major clonal Type II lineage together with the Type III lineage also found in Middle East, and an atypical genotype, Africa 1 appears consistent with the specific geographic location of Turkey between three continents and raises the possibility of transportation of these strains between continents through trade routes or long distance migratory birds. In addition, the first large study of toxoplasma seroprevalence in a stray cat population was also reported. The relatively high seropositivity rates and the variety of T. gondii genotypes confirm the local stray cat population as a risk factor for human toxoplasmosis in Izmir.Öğe Glycosylation changes leading to the increase in size on the common core of N-glycans, required enzymes, and related cancer-associated proteins(Tubitak Scientific & Technical Research Council Turkey, 2014) Karacali, Sabire; Izzetoglu, Savas; Deveci, RemziyeGlycan parts of glycoconjugates on the surfaces of cells regulate many kinds of interactions between the cells and their immediate environments. Alterations in glycosylation on the cancer-associated glycoproteins are responsible for changes in their molecular interactions and biological functions. Glycosylation changes occur in the core and/or at the nonreducing end of the oligosaccharide chains of N-glycans. In this review, we focus on the branching of the common core structure of N-glycans, the responsible enzyme, and the extensions of some of the branches causing size increases on the surface of tumor cells. Abnormal branching, elongation of the branches, and increasing size of the common core of N-glycans are the typical features of these changes and are related with malignant transformations. Seven N-acetylglucosaminyltransferases (GnTs) (GnT-I, GnT-II, GnT-III, GnT-IV, GnT-V, GnT-VI, and GnT-IX) and a1,6-fucosyltransferase (FUT8) initiate the new branches on the core. GnT-IV, GnT-V, and GnT-IX initiate the branches available for poly-LacNAc extensions, which are responsible for tumor progression and metastasis. GnT-III prevents the catalytic activity of GnT-II, GnT-IV, GnT-V, and FUT8 to form branching and elongation of the branches. The contributions of GnT-III and the other enzymes to the cancer progression are in conflict with each other. While GnT-III prevents cancer, the others increase metastasis. The function of FUT8 is related to signal transduction and its activity is higher in tumor tissue than in healthy tissue. The impact of glycosylation changes on some of the cancer-associated proteins (growth factor receptors, adhesion and signal molecules, CD147, TIMP-1, and matriptase) is also summarized.Öğe Human embryonic stem cell N-glycan features relevant to pluripotency(Tubitak Scientific & Technical Research Council Turkey, 2016) Karacali, SabireHuman embryonic stem cells (hESCs) and reprogrammed human induced pluripotent stem cells (hiPSCs) proliferate indefinitely in the undifferentiated state (self-renewal) and differentiate into the three germ layers (and ultimately into all cell types) (pluripotency). Branching in the N-glycan core of hESCs/hiPSCs is limited. hESCs/hiPSCs have high mannose-type and biantennary complex-type core structures, indicating immature stages of N-glycoproteins. The two branches on the core consist of type 2 N-acetyllactosamine (LacNAc), completed mainly with alpha 2,6-linked sialic acid. Complex terminal fucosylation, particularly alpha 1,2-linked fucosylation, is another characteristic N-glycosylation feature of hESCs/hiPSCs. All of these structural features are probably associated with the pluripotency of hESCs/hiPSCs. In differentiated cells, two-, three-, and four-branched N-glycan core structures are seen and N-acetylhexosamine compositions increase in the branches. The elongation and size of the branches in the N-glycan cores increase by the addition of poly-LacNAc chains and are the typical features during differentiation. As alpha 1,2-linked terminal fucosylation disappears, alpha 1,6-linked core fucosylation increases. It is necessary to know the pluripotency-associated glycans in order to identify and isolate the pluripotent cells from heterogeneous populations containing differentiated cells.Öğe Monosaccharide profiling of silkworm (Bombyx mori L.) nervous system during development and aging(Springer Heidelberg, 2016) Soya, Seckin; Sahar, Umut; Karacali, SabireGlycoconjugates have various functions in differentiation, development, aging and in all aspects of normal functioning of organisms. The reason for increased research on this topic is that glycoconjugates locate mostly on the cell surface and play crucial biological roles in the nervous system including brain development, synaptic plasticity, learning, and memory. Considering their roles in the nervous system, information about their existence in the insect nervous system is rather sparse. Therefore, in order to detect monosaccharide content of N- and O-glycans, we carried out capLC-ESI-MS/MS analysis to determine the concentration changes of glucose, mannose, galactose, N-acetylglucosamine (GlcNAc), N-acetylgalactosamine (GalNAc), fucose, xylose, arabinose, and ribose monosaccharides in the nervous system of Bombyx mori during development and aging processes. In addition to LC-MS, lectin blotting was done to detect quantitative changes in N- and O-glycans. Developmental stages were selected as 3rd (the youngest sample), 5th (young) larval instar, motionless prepupa (the oldest sample), and pupa (adult development). Derivatization of monosaccharides was performed with a solution of PMP agent and analyzed with capLC-ESI-MS/MS. For lectin blotting, determination of glycan types was carried out with Galanthus nivalis agglutinin and Peanut agglutinin lectins. In all stages, the most abundant monosaccharide was glucose. Although all monosaccharides were present most abundantly in the youngest stage (3rd instar), they are generally reduced gradually during the aging process. It was observed that amounts of monosaccharides increased again in the pupa stage. According to lectin blotting, N- and O-linked glycoproteins expressions were different and there were some specific glycoprotein expression differences between stages. These findings suggest that the glycosylation state of proteins in the nervous system changes during development and aging in insects in a similar fashion to that reported for vertebrates.Öğe A Novel Site for Hematopoietic Organ in Bombyx mori L. (Lepidoptera: Bombycidae)(Kafkas Univ, Veteriner Fakultesi Dergisi, 2010) Izzetoglu, Savas; Karacali, SabireA novel site for hematopoietic organ closely associated with the dorsal vessel (HPO-DV) in the fifth-final larvae of Bombyx mori L. was described. HPO-DV is composed of several lobes located very close to the dorsal vessel in the thorax and in the abdominal segments of the larvae. The anterior lobes contain big secretory cells. Loose hemocyte clusters among the secretory cells were observed particularly in the posterior lobes. When the HPO-DV was cultured in the absence of hemolymph; prohemocytes, plasmatocytes, and granulocytes were released from the hematopoietic organ. Cultured hemocytes from two sources, released from HPO-DV and circulating in the hemolymph, were compared under inverted microscope. They remained the suspended in culture medium. Conversely, the cells in the hemolymph immediately adhered on the flask. This different behavior of the cells obtained from different sources implies that the cells produced from the HPO-DV probably continue to differentiate in the hemocoel.Öğe Reliability of Intravitreal Nepafenac in Rabbits(Mary Ann Liebert, Inc, 2015) Afrashi, Filiz; Hashas, Arzu Seyhan Karatepe; Shahbazov, Cahit; Arici, Mesut; Yikilmaz, Mehmet Salih; Deveci, Remziye; Karacali, Sabire; Sahar, UmutPurpose: The purpose of this experiment was to investigate the possible toxic effects of Nepafenac, a nonsteroidal anti-inflammatory molecule, after its intravitreal application in various concentrations. Methods: Forty pigmented rabbits were randomly divided into 4 groups, each including 10 rabbits. The active ingredient Nepafenac was prepared to be applied in different doses, for intravitreal use. Under topical anesthesia, following pupil dilatation, 0.3, 0.5, 0.75, and 1.5 mg doses of Nepafenac was applied intravitreally into the right eye. In each rabbit, the right eye was considered to be the study group. Saline was injected intravitreally into the left eye of each rabbit, and these eyes were considered to be the control group. Immediately after the injection and at the 1st, 4th, and 8th weeks, fundus examination by indirect ophthalmoscopy and intraocular pressure measurement were conducted. Furthermore, electroretinographic (ERG) recordings were taken at the 4th and 8th weeks. At the end of the 8th week, eyes of the surviving 26 rabbits were enucleated, and then animals were sacrificed. Following necessary fixation procedures, histopathological investigations were conducted by using a light and electron microscope. In the histological cross sections, differences between the eyes with injection and the control group were evaluated, and total retinal thickness, inner nuclear layer thickness, and outer nuclear layer thickness were measured. Results: No pathology was found by clinical examination of either group. In the photopic and scotopic full-field ERG, conducted before the injection and in the 4th and 8th weeks after the injection, no statistically significant difference was determined between the study group and the control group. In the histological evaluation of the preparations, there were no statistically significant differences in the retina thickness of control and study groups. In the electron microscopic examinations, there were no toxicity findings in the eyes with injection. Conclusions: Our data show that intravitreal application of 0.3, 0.5, 0.75, and 1.5 mg doses of Nepafenac active substance is nontoxic to the rabbit retina.Öğe Ultrastructural Dynamics of Transendothelial Migration of Lymphocytes Through High Endothelial Venules (HEVs) of the Mucosa Associated Peyer's Patches(Periodicum Biologorum, 2017) Balcan, Erdal; Karacali, SabireBackground and Purpose: Although the pivotal role of high endothelial venules (HEVs) in the migration of leukocytes from the blood into the secondary lymphoid parenchyma is well established, conflicting ideas concerning the cellular dynamics both of leukocytes and endothelial cells throughout the migratory processes have been present. Here we focused specifically on the cellular dynamics of HEVs from Peyer's patches in an ultrastructural perspective. Materials and Methods: In order to determine the microstructural organization of transendothelial migration we used conventional methods for transmission electron microscopy. Results: Our results indicate that both lymphocytes and endothelial cells are highly active in the processes of transmigration steps, and a series of morphological and cellular alterations can occur depending upon their activity. Various types of cellular protrusions provide a direct contact between luminal lymphocytes and the endothelial cells at the initial phases of the migration. The endothelial protrusions subsequently embrace the lymphocytes and guide them into lymphoid stroma during the transcellular migration. Meanwhile, different sizes of vesicles show different cellular localizations according to their roles. The vesicles which are clustered near the lateral borders and the stand alone ones found only in the abluminal surfaces of endothelial cells might be involved in the paracellular migration. Concurrently, the other types of vesicles were smaller and appeared in the lateral border of the endothelial cells. Differ from the clustered and abluminally localized vesicles, they were closely related with plasma membranes. Conclusions: These results indicated that not only adhesion molecules, but also cellular dynamics of leukocytes and endothelial cells regulate the leukocyte traffic into lymphoid stroma or vice versa.
