Dış ortamda yer alan çeşitleri kimyasal kirliliklerin embriyo gelişimi üzerine etkisini değerlendirmede Fetax testinin değeri

TEZ2030Tez (Yüksek Lisans) -- Çukurova Üniversitesi, Adana, 1996.Kaynakça (s. 79-82) var.83 s. : rnk. res. ; 30 cm.

Nikel, magnezyum, kobalt, kadmiyum, çinko klorür'ün teratojenik ; embriyotoksik etkilerinin fetax testi kullanılarak xenopus laevis'te araştırılması

TEZ5143Tez (Doktora) -- Çukurova Üniversitesi, Adana, 2004.Kaynakça (s. 204-208) var.xxvi, 207 s. ; 30 cm.

Gibberellik asit'in (GA3GA_3) toksisite ve teratojenitesinin kurbağa embriyo teratogenezis testi (FETAX) kullanılarak değerlendirilmesi

Çalışmada, bitki büyüme düzenleyicisi gibberellik asitin ($GA_3$)(bir pestisit tipi) potansiyel gelişimsel toksisitesi FETAX testi kullanılarak değerlendirildi. Xenopus laevis embriyoları (evre 8-11); 96 saatlik statik yenileme test koşullarında, gibberellik asitin 11 konsantrasyonuna maruz bırakıldı. Muamelenin sonucunda, ortalama letal konsantrasyon ($LC_{50}$), ortalama malformasyon (EC50), etkinin hiç görülmediği konsantrasyon (NOAEC) ve etkinin ilk görüldüğü en düşük konsantrasyon (LOAEC) saptandı. Gibberellik asite muamele sonucu Xenopus embriyolarında elde edilen LC50 ve EC50 değerleri sırayla 1117,5 mg/L and 658 mg/L, TI ($LC_{50}/EC_{50}$) değeri ($GA_3$)= 1,69 olarak bulundu. Gibberellik asit konsantrasyonunun artışına paralel olarak embriyolarda farklı tip anomaliler gözlendi. Bu sonuçlara göre, gibberellik asitin Xenopus laevis embriyoları için toksik ve teratojenik bir madde olduğunu söyleyebiliriz. Ayrıca, elde ettiğimiz sonuçlar FETAX’ın tarımda kullanılan kimyasalların biyolojik zarar değerlendirmesinde bir ön test olarak kullanılabileceğini teyit etmektedir.This study investigated the developmental toxicity of a plant growth regulator (a type of pesticide) using the frog embryo teratogenesis assay-Xenopus (FETAX). Xenopus laevis embryos were exposed to 11 different concentrations of gibberellic acid ($GA_3$), from stage 8 to 11, for 96 h under static renewal test conditions. The median lethal concentration ($LC_{50}$), malformation ($EC_{50}$), non-observed adverse effect concentration (NOAEC), and lowest observed adverse effect concentration (LOAEC) were calculated. The corresponding ($LC_{50}$) and ($EC_{50}$)values determined for GA3exposure were 1117.5 mg/L and 658 mg/L, respectively. The TI (LC50/EC50) value calculated for ($GA_3$) was 1.69. Different anomalies occurred in the embryos, depending on the ($GA_3$) concentration. Based on these results, we conclude that ($GA_3$) is toxic and teratogenic to Xenopus laevis embryos. Moreover, our results confirm that the FETAX assay can be a useful pretest for integrated biological hazard assessment of chemical agents used in agriculture

Xenopus laevis'de deneysel embriyoloji

Xenopus laevis Türk bilim adamları için yeni bir hayvan modelidir. Ana amacımız, laboratuvarımızda FETAX testini (Frog Embryos Teratogenesis Assay: Xenopus) kurmaktır. Bu çalışmada, Xenopus'un geniş kullanım alanları tanıtıldıktan sonra laboratuvar koşullarında üreme, besleme, havalandırma ve populasyon yoğunluğu parametreleri sunuldu. Çiftleşmeyi indüklemek için dişiye 1000 İ.U, erkeğe 500 LU. human chorionic Gonadotropin (hcG) dorsal lenf bezlerine enjekte edildi. Ampleksus 2-6 saat içinde başladı ve yumurta bırakma enjeksiyondan sonra 9-12 saat kadar sürdü. Yumurtaların, normal ve fertil olup olmadıkları mikroskopla saptandı. Sıcaklığın Xenopus embriyolarının gelişimini nasıl etkilediğini bulmak için kontrol grubu olarak 20-22 °C ve deney grubu olarak 24-26 °C sıcaklıklarda iki grup alındı. Beslenmenin etkisini araştırmak için kontrol grubu haftada iki kez, deney grubu her gün beslendi. Sonuç olarak, larvaların 24-26 °C sıcaklıkta hergün beslenerek, kaplarından sürekli hava geçirilerek ve her birey için yeterli genişlikteki kaplarda en iyi şekilde geliştiği bulundu.Xenopus laevis is a new experimental subject for Turkish scientists. Our main goal was to set up FETAX (Frog Embryos Teratogenesis Assay: Xenopus) in our laboratory. In this study, after discussing the wide-ranging uses of Xenopus laevis. we present the breeding, feeding, housing and population density conditions of Xenopus laevis in the laboratory. To induce mating, males and females were given, respectively, 500 and 1000 I.U.'s of human chorionic gonadotropin via injection into the dorsal lymph sac. Amplexus normally ensued within 2 to 6 hours and deposition of eggs took place within 9 to 12 hours of injection. The embryos were then examined under microscope to determine if the eggs had been normally fertilized. In order to determine how temperature, feeding, aeration, and population density affect the developmental ratio of Xenopus embryos, we studied two groups: a control and an experimental group. It was concluded that optimum growth and development of larvae occur when they are kept at about 24-26 °C temperature, fed once a day, constantly aerated and given enough space for the growth of each individual

The effects of zinc chloride during early embryonic development in zebrafish (Brachydanio rerio)

This study investigated the developmental toxicity of zinc chloride (ZnCl2) in zebrafish embryos (Brachydanio rerio, Cyprinidae, Cypriniformes). Zebrafish embryos were exposed to 5 different concentrations of ZnCl2, from the blastula stage, for 15 days under static renewal test conditions. As a result, the corresponding median lethal concentration (LC50) value determined for ZnCl2 exposure was 1.36 mg/L (0.65 mg/L as a lone Zn2+ ion). At 1.0 mg/L ZnCl2, the exposed group’s hatching began at 7 days instead of at 4 days, and most of the embryos died in the chorion without hatching at 11 and 12 days. Developmental deformities such as abnormal embryogenesis, low hatchability, delayed hatching, and reduction of newly hatched larvae, and a poor survival ratio (mortality ratio of 1.5 and 10 mg/L concentrations compared to control, P < 0.001), were observed during the embryo larval stage due to zinc exposure. Based on these results, we observed that critical and teratogenic effects of ZnCl2 on embryonic development of zebrafish occurred at concentrations greater than 0.5 mg/L. Moreover, our results confirm that the zebrafish embryo teratogenesis assay can be a useful pretest for integrated biological hazard assessment of chemical agents used in industrial production and drug development technologies.This study investigated the developmental toxicity of zinc chloride (ZnCl2) in zebrafish embryos (Brachydanio rerio, Cyprinidae, Cypriniformes). Zebrafish embryos were exposed to 5 different concentrations of ZnCl2, from the blastula stage, for 15 days under static renewal test conditions. As a result, the corresponding median lethal concentration (LC50) value determined for ZnCl2 exposure was 1.36 mg/L (0.65 mg/L as a lone Zn2+ ion). At 1.0 mg/L ZnCl2, the exposed group’s hatching began at 7 days instead of at 4 days, and most of the embryos died in the chorion without hatching at 11 and 12 days. Developmental deformities such as abnormal embryogenesis, low hatchability, delayed hatching, and reduction of newly hatched larvae, and a poor survival ratio (mortality ratio of 1.5 and 10 mg/L concentrations compared to control, P < 0.001), were observed during the embryo larval stage due to zinc exposure. Based on these results, we observed that critical and teratogenic effects of ZnCl2 on embryonic development of zebrafish occurred at concentrations greater than 0.5 mg/L. Moreover, our results confirm that the zebrafish embryo teratogenesis assay can be a useful pretest for integrated biological hazard assessment of chemical agents used in industrial production and drug development technologies

Lityum ile Xenopus leavis embriyolarının morfolojik değişiklikleri ve Fetax testinin değerlendirilmesi

Bu çalısmada esas hedef FETAX testini standardize etmektir. Lityum iyonunun birçok organizmanın embriyoları için teratojenik oldugu bilindiginden lityum, ilk standardizasyon deneyimiz için tercih edilmistir. Xenopus laevis embriyoları, LiCl (2x10–4 M – 6x10–3M) ile 96 saat 2–4 hücreli evrede muamele edilmistir. Düsük konsantrasyonlar embriyoların normal yasam ve gelismesine olanak vermistir. Diger yandan; artan LiCl konsantrasyonuna baglı olarak vücut uzunlugu ve yasama oranı yüzdesi azalmıstır. Ayrıca yasayabilirlik yüzdesindeki azalma ve anomali yüzdesindeki artıs yüksek konsantrasyon oranları ile paralellik göstermistir. Kırık kuyruk ve ödem en çok görülen anomaliler olarak saptanmıstır. Mikrosefali, siklopia, mikromyelia, depigmentasyon, makrosefali, spina bifida, anteriozasyon, posteriozasyon, medialde yerlesmis gözler ve yolk anomalisi daha az sıklıkta görülen anomaliler olarak bulunmustur. 96 saat’lik LC50 ve EC50 degeri sırası ile 0.002g/L ve 0.0088g/L olarak bulunmustur. Teratojenite indeksi ise 2.5 olarak bulunmustur. Bu sonuçlar lityum klorürün orta siddette bir teratojen oldugunu göstermektedir.The main goal was to standardize the FETAX (Frog Embryos Teratogenesis Assay: Xenopus) test. Since lithium ions are known to be teratogenic for embryos of many organisms, they were prefferred for our first standardization assay. Xenopus laevis embryos were exposed to lithium chloride (from 2x10 -4 to 6 x 10 -3 M concentrations) for 96 hours at 2-4 cell stages of development. Exposure to lower LiCl concentrations permitted larvae to survive and to develop into normal ones. On the other hand, depending on the increase in the LiCl concentration, the body length and survival rate (%) decreased. In addition, the decreased survival and increased malformation rates were shown to be parallel with the increased concentration rates. The most common abnormalities were found to be tail kinks and edema. The less frequents abnormalities were microcephaly, cyclopia, shortening of the trunk (micromyelia), depigmentation, macrocephaly, spina bifida, anteriozation, posteriozation, medially located eyes and abnormally of the yolk. In the Fetax test, at ninety-six hours, LC 50 value was 0.002 g/L, and EC 50 value was 0.0088g/L for lithium chloride. Finally, the teratogenicity index was found to be about 2.5. These results showed that lithium chloride was a moderate teratogen

Evaluation of E330-induced developmental toxicity using FETAX

The present study evaluates the teratogenic and toxicological effects of citric acid (E330), a food additive, on Xenopus laevis embryos. The embryos were exposed to a range of E330 concentrations, from stage 8 to 11 of development, for 96 h under static renewal test conditions. The median lethal concentrations, no-observed adverse effect concentration (NOAEC), lowest observed adverse effect concentration (LOAEC), and minimum concentration to inhibit growth (MCIG) values were calculated. The lethal concentration (LC) values LC10, LC20, LC30, LC40, and LC50 determined for E330 exposure were 0.0113, 0.0117, 0.0119, 0.0122, and 0.0124 g/L, respectively. NOAEC and LOAEC values were calculated as 0.001 and 0.01 g/L. Since the effective concentration (EC50) value could not be determined, the E330 teratogenic index (TI), which is LC50/EC50, was not calculated. MCIG was calculated to be 0.010 g/L. The anomaly rate in Xenopus embryos treated with E330 was quite low. Therefore, the endpoint for the Xenopus embryos was whether they were alive or dead at the end of the study. It can be concluded from these observations that using unlimited amounts of E330 may result in preterm birth or abortion in humans, and E330 usage must be reevaluated and, potentially, limited. Moreover, our results confirm that the Frog Embryo Teratogenesis Assay Xenopus (FETAX) can be a useful pretest for integrated biological hazard assessment.The present study evaluates the teratogenic and toxicological effects of citric acid (E330), a food additive, on Xenopus laevis embryos. The embryos were exposed to a range of E330 concentrations, from stage 8 to 11 of development, for 96 h under static renewal test conditions. The median lethal concentrations, no-observed adverse effect concentration (NOAEC), lowest observed adverse effect concentration (LOAEC), and minimum concentration to inhibit growth (MCIG) values were calculated. The lethal concentration (LC) values LC10, LC20, LC30, LC40, and LC50 determined for E330 exposure were 0.0113, 0.0117, 0.0119, 0.0122, and 0.0124 g/L, respectively. NOAEC and LOAEC values were calculated as 0.001 and 0.01 g/L. Since the effective concentration (EC50) value could not be determined, the E330 teratogenic index (TI), which is LC50/EC50, was not calculated. MCIG was calculated to be 0.010 g/L. The anomaly rate in Xenopus embryos treated with E330 was quite low. Therefore, the endpoint for the Xenopus embryos was whether they were alive or dead at the end of the study. It can be concluded from these observations that using unlimited amounts of E330 may result in preterm birth or abortion in humans, and E330 usage must be reevaluated and, potentially, limited. Moreover, our results confirm that the Frog Embryo Teratogenesis Assay Xenopus (FETAX) can be a useful pretest for integrated biological hazard assessment