1,721,008 research outputs found
Evaluation of spatial and temporal changes in biomarker responses in the common carp (Cyprinus carpio L.) for biomonitoring the Meric Delta, Turkey
No full textErkmen, Belda (Aksaray, Yazar)The aim of this study is to examine the activity of several biomarkers in carp, Cyprinus carpio L., to determine their response to xenobiotics, such as organochlorine pesticides (OCPs), in the Meriç Delta. Fish were collected from contaminated sites and from areas regarded as relatively less contaminated in four sampling periods. Hepatic glutathione S-transferase (GST), carboxylesterase (CaE), lactate dehydrogenase, aspartate aminotransferase, and acid phosphatase activities were measured as biomarkers in the fish. For all fish, the condition factor and hepatosomatic index, were calculated to determine the condition of the fish. The results of this study indicated that the mean GST activity showed an increase in fish from the Meriç-Ergene junction site and a decrease in Enez site with respect to fish from Meriç site. Furthermore, the study shows that spatial and temporal changes of biomarkers such as GST and CaE might be useful for the assessment of environmental contamination in the Meriç Delta
A prelımınary hıstologıcal study on ovarıum development ın mırror carp and scaled carp (Cyprinus Carpio L., 1758) ıntroduced ınto gelıngüllü reservoır, Turkey
Full text linkErkmen, Belda (Aksaray, Yazar)Carp (Cyprinus carpio) is the most common species of
the Cyprinidae family and is among the important
species commercially caught in the Gelingüllü Reservoir, Yozgat, Turkey. In this study, the reproductive
biology of mirror carp and scaled carp in Gelingüllü
Reservoir was studied in terms of the gonadosomatic
index (GSI), fecundity, and ovarian histology. Ovaries
were classified into 5 maturity stages based on histological data, as follows: 1. Chromatin-nucleolus stage
(oocyte diameter is 20-60 µm); 2. Peri-nucleolar stage
(oocyte diameter is 60-200 µm); 3. Cortical alveolar
stage (oocyte diameter is 200-600 µm); 4. Vitellogenic
stage (oocyte diameter is 600-1000 µm); 5. Maturation
stage (oocyte diameter is 1000-1400 µm). When ovulation was completed, post-ovulatory follicles and
atretic follicles were noted in the ovaries. The spawning period in both populations extended from April to
July, but peak-spawning activity occurred in April and
May. Absolute fecundity reached 2.133 million eggs
in mirror carp and 1.628 million eggs in scaled carp.
Ovaries that contained both yolk stage oocytes and
postovulatory follicles indicated that carp is a multiple
spawner. Histological analysis in the present study
showed that female mirror carp and scaled carp had
mature eggs that contributed to sustaining the both
populations in Gelingüllü Reservoir
Detection of aquatic pollution in meric river by a measure of developmental instability, fluctuating asymmetry in the fish, common carp, Cyprinus carpio L., 1758
No full textErkmen, Belda (Aksaray, Yazar)A deviation measure of bilateral symmetry, developmental instability (Fluctuating Asymmetry, FA) was estimated with two different indexes (namely, FA1 and FA11) from the samples of common carp, Cyprinus carpio from different collection sites in a highly polluted Meric river system of Turkey. Researchers used three traits of the carp, i.e., head length, eye diameter and barbie length to estimate an index of fluctuating asymmetry separately for each trait (FAls) and for the all the three traits combined (FA1 Is). Only FA1 of the eye diameter resulted in significant deviaton from the symmetry when the most polluted site compared to the others. Researchers suggest that developmental instability may be a relevant indicator of pollution as well as the classical markers. We observe as from the study that choice of multiple traits would be helpfull to reveal possible candidates of fluctuating asymmetry for further use in the like model organism
Sub-lethal Effects of Imidacloprid on Nile Tilapia (Oreochromis niloticus)
No full textErkmen, Belda ( Aksaray, Yazar )Imidacloprid (1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine (CAS No: 138261–41-3), neonicotinoid insecticide, and agricultural plant protectants were applied as seed and soil treatments. The aim of the present study is to determine the effects of sub-lethal imidacloprid concentrations on the histopathology and oxidative stress parameters with lipid peroxidation (LPO) to standard non-target test organism, tilapia (Oreochromis niloticus). 50 and 100 mgL−1 imidacloprid concentrations were chosen for experimental groups with control group. Fish were stocked in 60 L glass aquaria, maintained in aerated and dechlorinated tap water. The mean weight and length of tilapia were 37.78 ± 2.19 g and 12.98 ± 0.22 cm, respectively. After 24 and 96 h exposure to sub-lethal imidacloprid concentrations, the fish were sacrificed; tissue samples of gill and liver were snap frozen in liquid nitrogen for oxidative stress parameters and LPO assays, fixed (buffered 10% formalin) for histopathology. After exposure to sub-lethal imidacloprid, LPO was induced in both tissues. MDA levels were increased in both tissues, while GSH levels were reduced at the high concentration of imidacloprid in the gill tissues after 96 h and both concentrations in the liver tissues (P 0.05). Gill tissues revealed hyperaemia, epithelial lifting, fusion of secondary lamellae and telangiectasia, whereas hyperaemia, mononuclear cell infiltration vacuolization of hepatocytes and hydropic degeneration were observed in liver tissues. Imidacloprid is very toxic to the non-target species in the aquatic ecosystem even at sub-lethal concentrations
Investigation of insecticidal activities of neonicotinoidgroup efficienciesagainstadult housefly (musca domestica l.diptera:muscidae) populations
No full textBu çalışmada, Sağlık Bakanlığı "İzinli Biyosidal Ürünler Envanteri"nde yer alan neonikotinoid grubu insektisitlerden CAS No: 153719-23-4 thiamethoxam, CAS No:138261-41-3 imidakloprid, CAS No:135410-20-7 acetamiprid ve CAS No:210880-92-5 clothianidinin ev sineğinin (Musca domestica L.) Ankara populasyonlarındaki biyolojik etkinlikleri incelenmiştir. Laboratuvar koşullarında WHO (Dünya Sağlık Örgütü)'nun yemleme metoduyla 10x10x20 cm tül kafeslerde biyolojik etkinlik deneyleri yapılarak populasyonların etkinlikleri belirlenmiştir. Populasyonların nesillerinin devamlılığı 2012 yılından bu yana laboratuvar koşullarında sağlanmış ve sağlanmaya devam etmektedir. İncelenen neonikotinoidler, standart duyarlı (WHO) popülasyonu ile, Ankara ili ve ili temsil eden gen havuzundan toplanan Sincan Çadırtepe Çöplüğü, Mamak Çöplük, Gölbaşı Hayvan Barınağı, Çubuk Büğdüz Mevki ve Hacettepe Üniversitesi Referans Laboratuvarından temin edilen Beytepe populasyonları biyolojik etkinlik deneylerinde kullanılmıştır. Deneylerde 5.,15.,30. dakikalarda Knock Down sonuçlarına göre Probit Analiz Metodu (Finney,1971)ile KT50 değerlerihesaplanmış ve duyarlı popülasyonla karşılaştırma yapılarak dirençleri(R/S) belirlenmiştir.Bu değerler incelendiğinde; İmidaclopride karşı Beytepe popülasyonu, acetamipride karşı Sincan popülasyonu, thiamethoxama karşı Çubuk Populasyonu ve clothianidine karşı ise Beytepe popülasyonunda yüksek direnç(R/S)tespit edilmiştir. 24.,48.,ve 72. saat ölüm değerlerine göre de LT50 değerleri hesaplanmış ve duyarlı popülasyonla karşılaştırma yapılarak R/S belirlenmiştir. Bu değerler incelendiğinde ise; imidaklopride ve thiamethoxama karşı Mamak popülasyonu, acetamipride karşı Gölbaşı popülasyonu ve clothiniadine karşı Sincan popülasyonunda yüksek direnç (R/S) tespit edilmiştir. Neonikotinoid grubu insektisitlere göre değişen oranlarda direnç geliştiği gözlemlenmiştir
Histopathological effect of Acrylamide to common carp (Cyprinus carpio 1758 L.) gills
No full textBu tez çalışmasında, Akrilamid'in sazan balıklarının (Cyprinus carpio,1758 L.) solungaçları üzerine histopatolojik etkileri araştırılmıştır. Araştırmada iki farklı doz akrilamid (10 ve 50 mg/L) 96 saat boyunca, sazan balıklarına uygulanmıştır. Deney sonrasında solungaç dokuları histopatolojik yöntemlere uygun bir biçimde hazırlanmıştır. Akrilamidin subletal dozlarına maruz kalan uygulama gruplarında kontrol grubuna göre bazı histopatolojik değişiklikler (sekonder lamellerde birleşme, kısalıp kalınlaşma, dökülme, ödem oluşumu, kıkırdak doku hasarı, epitel dokuda ayrılma, hiperemi, telengiektazi, hiperplazi ve mukus hücrelerinde artış) meydana gelmiştir. Söz konusu olan bu değişikliklerin en temel nedeni, solungaçların dış ortamla direkt temas halinde olmasıdır. Ayrıca solungaçların ince membranlara ve geniş yüzey alanına sahip olmasının bu durumu attırdığı düşünülmüştür. Akrilamid ile yapılan çalışmalar incelendiğinde benzer sonuçların elde edildiği görülmüştür ve bizim çalışmamızı destekler niteliktedir.Histopathological effects of acrylamide on gills of the common carp (Cyprinus carpio, 1758 L.) were studied in the present thesis. Acrylamide was applied to carp during 96 hours in two different exposure concentrations of 10 and 50 mg/L. Gill tissue were evaluated using appropriate histopathological methods at the end of the experiments. Several histopathological lesions were found in acrylamide exposure groups such as fusion of secondary lammalae, shortening and thickening, exfoliation, oedema formation, cartilage tissue damage, epithelial lifting, hyperemia, telengiectasis, hyperplasia and increases in mucus cells, when compared with the control group. The major reason for these changes were due to gills being in direct contact with the environment. In addition the gill thin membranous structure and large surface area of the gills augmented this situation. Work of others with acrylamide showed similar results and were supporting our finding
Determination of toxicity of acrylamide on narrow clawed crayfish (Astacus leptodactylus Esch. 1823)
No full textAkrilamid, poliakrilamid malzemeleri yapmak için kullanılan, yüksek ısıda protein ile şekerin reaksiyona girmesi sonucu ortaya çıkan bir kimyasaldır. Akrilamid çevrede çok düşük konsantrasyonlarda bulunsa bile, son yıllarda endişe yaratan kimyasal grupları arasında yerini almıştır. Çalışmada, tatlı su ıstakozu dipte beslenmesi, besin zincirindeki önemi ve OECD gibi uluslararası kuruluşlar tarafından standart test organizması olması yönüyle tercih edilmiştir. Bu çalışmada Türkiye'de geniş bir dağılım gösteren tatlı su ıstakozu Astacus leptodactylus'un dokularında, çevresel kirletici olarak yaygın bulunan akrilamidin, subletal düzeylerine (100 ve 200 mg/L) 48 saat ve 7 gün süre maruziyetin toplam hemosit sayıları ile solungaç ve hepatopankreas dokularındaki histopatolojik etkileri araştırılmıştır. Çalışmada uygulama grubu tatlı su ıstakozlarının toplam hemosit sayılarının kontrol grupları ile karşılaştırıldığında istatistiksel olarak önemli düzeyde bir azalma gösterdiği saptanmıştır (p< 0.05). Araştırmada, solungaç ve hepatopankreas dokuları histolojik yöntemlere uygun bir biçimde hazırlanmış ve histopatolojik yönden incelemeleri yapılmıştır. Akrilamidin subletal dozlarına maruz kalan uygulama gruplarında kontrol gruplarına göre bazı histopatolojik değişiklikler gözlenmiştir. Uygulama grubu solungaç dokularında solungaç lamellerinde deformasyon ve solungaç lamellerinde hipertrofi (genişleme), hepatopankreas dokularında ise, hepatopankreatik dokuda dejenerasyon ve focal tübül epitel hücre nekrozu gibi histopatolojik dejenerasyonlar saptanmıştır. Tespit edilen bu değişiklikler her bir uygulama grubuna ait tatlı su ıstakoz örneklerinde farklı sıklıklarda olmakla birlikte, hemen hemen bütün örneklerde kaydedilmiştir. Histopatolojik bulgular artan doz ve maruziyet süresine bağlı olarak artış göstermiştir.Acrylamide is a chemical used to make polyacrylamide materials, resulting from the reaction of protein and sugar at high temperatures. Although acrylamide is found in very low concentrations in the environment, it has become one of the chemical groups of concern in recent years. In the study, freshwater crayfish was chosen as a standard test organism by international organizations such as OECD, and its importance in the food chain. In this study, the crayfish Astacus leptodactylus, widely distributed in Turkey, exposed to environmental pollutant of acrylamide at sublethal levels (100 and 200 mg / L) for 48 h and 7 days. Total hemocytes counts and gill and hepatopancreas tissue were investigated histologically after exposed to acrylamide exposed crayfisih. The total hemocyte counts of freshwater crayfish in the treatment group showed a statistically significant decrease compared to the control groups (p < 0.05). In the study, gill and hepatopancreatic tissues were prepared in accordance with histological methods and examined histopathologically. Some histopathological changes were observed in the exposure groups exposed to subletal doses of acrylamide compared to the control groups. Histopathological degenerations such as deformation in the gill lamellae and hypertrophy (enlargement) in the gill lamellae in the gill tissues of the exposed group and degeneration in the hepatopancreatic tissue and focal tubule epithelial cell necrosis were detected. Although these changes were at different frequencies in freshwater crayfish samples belonging to each application group, the lesionswere recorded in almost all exposed samples. Histopathological findings increased with increasing the dose and exposure time
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Spermiotoxicity and embryotoxicity of permethrin in the sea urchin paracentrotus lividus
No full textWOS: 000350874900003PubMed: 25634326The toxicity of permethrin on the fertilization and early development of sea urchin Paracentrotus lividus embryos were studied. Spermiotoxicity was evaluated on the basis of fertilization rate. Embryotoxicity was determined by comparing the frequency of normal development and malformations in embryos exposed to permethrin throughout their development. Permethrin inhibited fertilization success, and yielded IC25 and IC50 values of 0.58 (CL = 0.44-0.77) and 0.94 (CL = 0.92-0.95) A mu g/L, respectively. The embryotoxicity of permethrin was concentration dependent indicating a decreased percentage of normally developed plutei with increasing permethrin concentrations: IC25 = 0.195 A mu g/L (CL = 0.15-0.26) and IC50 = 0.346 A mu g/L (CF = 0.29-0.41). Associated with the decrease in normal pluteus frequency was an increase in larval malformations as skeleton deformities. The results suggest that permethrin is more highly toxic to embryos than to sperm, and that this insecticide may present a potential risk for the sea urchin in contaminated marine environments
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