Asynchronous expression of myeloid antigens in leukemic cells in a PML/RARalpha transgenic mouse model

Acute promyelocytic leukemia (APL) is characterized by the expansion of blasts that resemble morphologically promyelocytes and harbor a chromosomal translocation involving the retinoic acid receptor a (RARa) and the promyelocytic leukemia (PML) genes on chromosomes 17 and 15, respectively. The expression of the PML/RARa fusion gene is essential for APL genesis. In fact, transgenic mice (TM) expressing PML/RARa develop a form of leukemia that mimics the hematological findings of human APL. Leukemia is diagnosed after a long latency (approximately 12 months) during which no hematological abnormality is detected in peripheral blood (pre-leukemic phase). In humans, immunophenotypic analysis of APL blasts revealed distinct features; however, the precise immunophenotype of leukemic cells in the TM model has not been established. Our aim was to characterize the expression of myeloid antigens by leukemic cells from hCG-PML/RARa TM. In this study, TM (N = 12) developed leukemia at the mean age of 13.1 months. Morphological analysis of bone marrow revealed an increase of the percentage of immature myeloid cells in leukemic TM compared to pre-leukemic TM and wild-type controls (48.63 ± 16.68, 10.83 ± 8.11, 7.4 ± 5.46%, respectively; P < 0.05). Flow cytometry analysis of bone marrow and spleen from leukemic TM identified the asynchronous co-expression of CD34, CD117, and CD11b. This abnormal phenotype was rarely detected prior to the diagnosis of leukemia and was present at similar frequencies in hematologically normal TM and wild-type controls of different ages. The present results demonstrate that, similarly to human APL, leukemic cells from hCG-PML/RARa TM present a specific immunophenotype.

Lack of evidence for regulation of cardiac P-type ATPases and MAP kinases in transgenic mice with cardiac-specific overexpression of constitutively active α1B-adrenoceptors

The regulatory function of α1B-adrenoceptors in mammalian heart homeostasis is controversial. The objective of the present study was to characterize the expression/activity of key proteins implicated in cardiac calcium handling (Na+/K+-ATPase and Ca2+-ATPases) and growth (ERK1/2, JNK1/2 and p38) in mice with cardiac-selective overexpression of constitutively active mutant α1B-adrenoceptor (CAMα1B-AR), which present a mild cardiac hypertrophy phenotype. Immunoblot assays showed that myocardial plasma membrane Ca2+-ATPase (PMCA) expression was increased by 30% in CAMα1B-AR mice (N = 6, P < 0.05), although there was no change in sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2) expression. Moreover, total Ca2+-ATPase activity was not modified, but a significant increase in the activity of the thapsigargin-resistant (PMCA) to thapsigargin-sensitive (SERCA) ratio was detected. Neither Na+/K+-ATPase activity nor the expression of α1 and α2 subunit isoforms was changed in CAMα1B-AR mouse hearts. Moreover, immunoblot assays did not provide evidence for an enhanced activation of the three mitogen-activated protein kinases studied in this stage of hypertrophy. Therefore, these findings indicate that chronic cardiac α1B-AR activation in vivo led to mild hypertrophy devoid of significant signs of adaptive modifications concerning primary intracellular calcium control and growth-related proteins, suggesting a minor pathophysiological role of this adrenergic receptor in mouse heart at this stage of development.

Hydration kinetics, physicochemical composition, and textural changes of transgenic corn kernels of flint, semi-flint, and dent varieties

The hydration kinetics of transgenic corn types flint DKB 245PRO, semi-flint DKB 390PRO, and dent DKB 240PRO was studied at temperatures of 30, 40, 50, and 67 °C. The concentrated parameters model was used, and it fits the experimental data well for all three cultivars. The chemical composition of the corn kernels was also evaluated. The corn cultivar influenced the initial rate of absorption and the water equilibrium concentration, and the dent corn absorbed more water than the other cultivars at the four temperatures analyzed. The effect of hydration on the kernel texture was also studied, and it was observed that there was no significant difference in the deformation force required for all three corn types analyzed with longer hydration period.

Effect of storage period on isoflavone content and physiological quality of conventional and transgenic soybean seeds

The objective in this research was to evaluate the isoflavone content and the physiological quality of seed from conventional and transgenic soybean cultivars before and after 180 days of storage. Twenty one soybean cultivars: CD 202, CD 206, CD 208, CD 213RR, CD 214RR, CD 215, CD 216, CD 217, CD 218, CD 221, BRS 184, BRS 185, BRS 214, BRS 244RR, BRS 245RR, BRS 246RR, BRS 255, BRS 257, BRS 258, BRS 261 and BRS 262, grown in the 2005/2006 crop season, were assayed. The seeds were packed in Kraft paper bags and stored at room temperature under laboratory conditions. Seeds were evaluated with respect to their germination and vigor (first germination count, accelerated aging and tetrazolium test) and their total isoflavone contents and respective aglycon forms (daidzein, genistein and glycitein),glycosides (daidzine, genistine and glycitine) and malonyl conjugates. A completely randomized block design with six replications with the treatments set out within a subplot scheme (21 cultivars x 2 storage periods) was used. The F-test was used to compare means between storage periods and the Scott-Knott test to compare cultivars for each storage period, both with a 95% probability. It was concluded that isoflavone contents differ between cultivars and show a distinct behavior throughout storage.

Detection of adventitious presence of genetically modified seeds in lots of non transgenic soybean

The difficulty on identifying, lack of segregation systems and absence of suitable standards for coexistence of non trangenic and transgenic soybean are contributing for contaminations that occur during productive system. The objective of this study was to evaluate the efficiency of two methods for detecting mixtures of seeds genetically modified (GM) into samples of non-GM soybean, in a way that seed lots can be assessed within the standards established by seed legislation. Two sizes of soybean samples (200 and 400 seeds), cv. BRSMG 810C (non-GM) and BRSMG 850GRR (GM), were assessed with four contamination levels (addition of GM seeds, for obtaining 0.0%, 0.5%, 1.0%, and 1.5% contamination), and two detection methods: immunoassay of lateral flux (ILF) and bioassay (pre-imbibition into 0.6% herbicide solution; 25 ºC; 16 h). The bioassay is efficient in detecting presence of GM seeds in seed samples of non-GM soybean, even for contamination lower than 1.0%, provided that seeds have high physiological quality. The ILF was positive, detecting the presence of target protein in contaminated samples, indicating test effectiveness. There was significant correlation between the two detection methods (r = 0.82; p < 0.0001). Sample size did not influence efficiency of the two methods in detecting presence of GM seeds.