ABSTRACT
C57BL/6N is the most widely used inbred mouse strain applied in a wide variety of research areas including cancer, cardiovascular biology, developmental biology, diabetes and obesity, genetics, immunology, neurobiology, and sensorineural research. To compare the fertilization rates of C57BL/6NKorl mice with two commercial C57BL/6N stocks, differences in reproductive organ structures, sperm and egg numbers, fertilization rates, and embryo development rates among C57BL/6NKorl (Korea FDA source), C57BL/6NA (USA source), and C57BL/6NB (Japan source) mice were determined. Among the stocks, no significant differences were detected in organ weight and histological structure of male and female reproductive organs, although body weight was higher in C57BL/6NKorl mice than that in the other groups. The concentration and morphology of sperm and eggs in C57BL/6NKorl mice were similar to those of C57BL/6NA and C57BL/6NB mice. Furthermore, the three stocks had similar in vitro fertilization and embryo development rates, although these rates tended to be higher in C57BL/6NB mice. Pup body weight was higher in C57BL/6NKorl and C57BL/6NB mice than that in C57BL/6NA mice. The results of the present study suggest that C57BL/6NKorl, C57BL/6NA, and C57BL/6NB mice obtained from three different sources have similar fertilization and embryo development rates, although there were slight differences in the magnitude of their responses rates.
Subject(s)
Animals , Female , Humans , Male , Mice , Pregnancy , Allergy and Immunology , Biology , Body Weight , Developmental Biology , Eggs , Embryonic Development , Fertilization in Vitro , Fertilization , Genetics , Mice, Inbred Strains , Neurobiology , Obesity , Organ Size , Ovum , SpermatozoaABSTRACT
The diamondback moth, Plutella xylostella (L.), is the most important pest of brassicaceous crops worldwide. Since temperature is the major abiotic factor influencing insect development and thermal requirements may vary among insect populations, it is important to know the effect of temperature on development and survival of a subtropical strain of P. xylostella. Development and survival of the diamondback moth was evaluated under seven constant temperatures ranging from 10°C to 35°C. Development was completed between 10°C and 32.5°C, but at 35°C all individuals died in the larval stage. Data were fitted to one linear and five nonlinear models. Considering as criteria the goodness of fit and the ability to estimate parameters of biological significance, the models Briere-1 and Briere-2 were the most adequate to describe the relationship between temperature and development of P. xylostella. The linear model demonstrated that P. xylostella required 312.5 degree-days above a lower threshold of 6.3°C to complete development. The degree-day model showed that the number of diamondback moth generations in the tropical region of Brazil is nearly twice the number in the subtropical region of the country. This result explains, at least in part, the higher population levels of this species in the tropical region of Brazil, and also demonstrates that P. xylostella is tolerant to a wide range of temperatures (6.1-32.5°C). Therefore, temperature cannot be considered a limiting factor for the occurrence of diamondback moth throughout the year in most regions of Brazil.
Subject(s)
Animals , Moths/growth & development , Brazil , Temperature , Tropical ClimateABSTRACT
O efeito da temperatura sobre o desenvolvimento da broca do broto do mogno, Hypsipyla grandella (Zeller), foi determinado em laboratório, em Turrialba, Costa Rica. Para tanto, duzentos ovos com menos de 24h foram colocados individualmente em frascos de vidro e expostos às temperaturas de 10; 12,5; 15; 20; 25; 30 e 35oC. O estudo foi realizado em câmaras climáticas, com umidade de 80-90% e fotoperíodo de 8L:16D. Após a eclosão, as larvas foram alimentadas com folhas tenras de cedro (Cedrela odorata) einspecionados a cada 24h para determinar a duração das fases larval e de pupa, e a emergência dos adultosem cada temperatura. As relações entre essas variáveis e a temperatura foram analisadas através de ANOVA, regressão e correlação. A temperatura teve grande influência no desenvolvimento das fases imaturas e naemergência dos adultos de H. grandella. A duração do ciclo biológico (ovo-adulto) variou de 30 dias (30ºC) a 104 dias (15ºC). A mortalidade do estágio larval foi alta nessas temperaturas, alcançando taxas de 90% (15°C) e 45% (30ºC). A mortalidade de larvas de primeiro instar foi também relativamente alta (51-75%) nastemperaturas dentro do intervalo de 15ºC a 30ºC, com exceção daquelas que se desenvolveram a 25ºC (14%). O peso das pupas foi menor em temperaturas extremas (15ºC e 30ºC). A estimativa da temperatura base dedesenvolvimento para todos os estágios imaturos (8,5ºC) permitiu calcular a constante térmica (1320 graus dias), a qual possibilitará a previsão de picos populacionais no campo.
Developmental response of the mahogany shootborer, Hypsipyla grandella (Zeller), to temperature was determined in laboratory trials in Turrialba, Costa Rica. Two hundred fresh eggs (less than 24h old) were placed individually inside glass flasks, and exposed to seven constant temperatures (10, 12.5, 15, 20, 25, 30 and 35°C), in separate experiments. These were carried out in environmental chambers, at 80-90% relative humidity and 8L:16D photoperiod. After hatch, larvae were fed tender foliage of Spanish cedar (Cedrela odorata) and were inspected every 24h to determine larval and pupal duration, and adult emergence, at each temperature. Relationships between these variables and temperature were analyzed by means of ANOVA, regression and correlation procedures. Temperature greatly influenced development of H. grandella immature stages and adult emergence; development time varied between 30 days (30ºC) and 104 days (15°C). Larval mortality was high at those temperatures, reaching values of 90% (15°C) and 45% (30ºC). Also, mortality of the first larval instar was relatively high (51-75%) at all temperaturesin the range 15-30°C, except at 25ºC (14%). Pupal weight was lower at extreme temperatures (15ºC and 30ºC).Estimation of a common lower thermal threshold for all immature stages (8.5ºC) allowed calculation of a general thermal constant (1320 degree-days), which could be used to predict population peaks in the field.
ABSTRACT
OBJECTIVE: The purpose of this study was to evaluate the effect of CCB treatment on the survivability and in vitro development of mouse oocyte frozen by vitrification. METHODS: Mouse oocytes retrieved from cycle stimulated by PMSG and hCG were treated by CCB and then exposed to EFS-30. These oocytes were placed onto an EM grid and submerged immediately in liquid nitrogen. Thawing of the oocytes on EM grid was carried out at room temperature for 5 seconds, then the EM grid was placed into 0.75 M sucrose at 37degrees C for 3 minutes. This was followed by 0.5 M and 0.25 M sucrose for 3 minutes, each. We compared the survivability, cleavage and developmental rate of mouse frozen by vitrification between CCB treated and non-treated groups. Chi-square was used to determine statistical significance. statistical significance was defined as p<0.05. RESULTS: Survivability (79.3%) and developmental rate into blastocyst (52.3%) of mouse oocyte were markedly decreased after vitrification. There were no significant differences between CCB treated and non- treated groups regarding survivability of oocyte frozen by vitrification (80.3% vs 78.5%). The developmental rate into 2-cell in CCB treated group was significantly higher than that in non-treated group (69.7% vs 61.9%, p<0.05). The developmental rate into blastocyst in CCB treated group was higher than that in non-treated group (54.9% vs 51.5%), but the difference was not significant. CONCLUSION: Survivability of mouse oocyte could not be affected by CCB treatment and developmental rate into 2-cell was improved in CCB treated group. It is suggested that CCB treatment prior vitrification improve stability of cytoskeleton and then improve fertilization and early stage embryo development.