Complete mole in a dichorionic twin pregnancy after intracytoplasmic sperm injection

A dichorionic twin pregnancy with complete hydatidiform mole and coexistent fetus is a rare and challenging situation, whose pathogenesis has not been yet fully understood. We present a case of a 39-year-old woman who underwent intracytoplasmic sperm injection with two embryos transfer. The 12-week gestation ultrasound examination revealed normal fetus and placenta with features of hydatidiform mole, leading to pregnancy termination. Autopsy and histological examinations diagnosed a complete mole coexisting with a normal fetus, and the genetic analysis showed a diploid fetus with biparental genome and molar tissue with paternal diploidy. This case highlighted that complete molar pregnancies may still occur even though pregnancy is achieved after intracytoplasmic sperm injection. A review of the literature was performed by collecting data from the few similar reported cases and by commenting on the pathogenesis of this rare condition.

Resistance to ACCase inhibitors in Eleusine indica from Brazil involves a target site mutation

Eleusine indica (goosegrass) is a diploid grass weed which has developed resistance to ACCase inhibitors during the last ten years due to the intensive and frequent use of sethoxydim to control grass weeds in soybean crops in Brazil. Plant dose-response assays confirmed the resistant behaviour of one biotype obtaining high resistance factor values: 143 (fenoxaprop), 126 (haloxyfop), 84 (sethoxydim) to 58 (fluazifop). ACCase in vitro assays indicated a target site resistance as the main cause of reduced susceptibility to ACCase inhibitors. PCR-generated fragments of the ACCase CT domain of the resistant and sensitive reference biotype were sequenced and compared. A point mutation was detected within the triplet of aspartate at the amino acid position 2078 (referred to EMBL accession no. AJ310767) and resulted in the triplet of glycine. These results constitute the first report on a target site mutation for a Brazilian herbicide resistant grass weed.

Intrapopulational chromosome number variation in Zephyranthes sylvatica Baker (Amaryllidaceae: Hippeastreae) from Northeast Brazil

Zephyranthes Herb. is a taxonomically complex and cytologically variable group, with about 65 species of Neotropical distribution. Chromosome number variability in 32 individuals of a Zephyranthes sylvatica population from Northeast Brazil was investigated. Three cytotypes were found: 2n = 12 (one metacentric, four submetacentric and one acrocentric pairs), in 24 individuals; 2n = 12 + 1B, in five and three individuals with 2n = 18, a triploid cytotype. All diploid individuals showed chromosomes with polymorphism in pair one and two, while in triploids this polymorphism was observed in all chromosome triplets, generally with two homomorphic chromosomes and a higher or lower heteromorphic chromosome. All individuals had reticulated interfasic nucleus and a slightly asymmetric chromosome complement, with one metacentric chromosome pair and the others more submetacentric to acrocentric. These data confirm the cytological variability previously registered for the genus. Mechanisms involved in karyotypic evolution in this population are discussed.

Reproductive biology and cytology of Hypericum brasiliense Choisy (Hypericaceae)

This is the first study of reproductive biology and cytology carried out with Hypericum brasiliense, a species with medicinal properties and potential agronomic interest. Three populations of H. brasiliense collected at Southeastern Brazil were studied. The results indicate that H. brasiliense is preferentially allogamous, self-compatible, facultative apomitic and anemophilous. Male sterility was observed in about 50% of individuals from the three populations. Anatomical studies evidenced structural abnormalities in anthers of male sterile flowers, showing enlarged tapetal cells and thick secretion deposits on the tapetal cell surfaces that may cause nutritional deficit for pollen mother cells. In cytogenetic studies several haploid chromosome numbers were observed like n = 4, 8, 9, 11, 16 and 17, including the presence of multivalents and micronuclei in tetrads, indicating the occurrence of abnormalities in the meiotic process of H. brasiliense. Despite these meiotic abnormalities the pollen viability and in vitro pollen germination rate observed in fertile flowers may be considered high. The diploid chromosome number 2n = 16 was observed, and the chromosomes in metaphase were small and similar. Fluorochrome staining techniques using DAPI and CMA3 were applied, with no positive bands observed.

Chromosome studies in some Stevia. Cav. (Compositae) species from Southern Brazil

Karyotypes of six species of the genus Stevia from Southern Brazil were studied, utilizing root tip metaphases. All species were diploid with 2n = 22 chromosomes. It was possible to identify each species by chromosome morphology. The basic chromosome number for Brazilian species of Stevia is X = 11. This number is also found in almost all South American species. We suggest that in Stevia there is an evolutionary trend toward chromosomal rearrangement, caused mainly by pericentric inversions. It was found that, in addition to aneuploidy and polyploidy, chromosomal rearrangements are common in the tribe Eupatorieae.

Sex determination in honey bees (Apinae and Meliponinae) and its consequences

The first experiments on sex determination in bees began with Dzierzon, Meves, Nachtsheim, Paulcke, Petrunkewitsch, Manning. Whiting, (1943) found multiple alleles in Bracon xo that are the Rosetta stone of sex determination in Hymenoptera. Whiting also discovered that some species of microhymenoptera do not possess xo sex alleles. Therefore, Hymenoptera apparently presents two types of sex determination superimposed on haplodiploidy. In the panmictic groups hemizygous (xo1, xo2,... xon) and homozygous (xo1xo1, xo2xo2... xonxon) are males while heterozygous (xo1xo2, ... xon-1xon) are females. There is no such series of xon in endogamous Hymenoptera, since the constant elimination of diploid males would be damaging to the population and the mutation of xo to xon would be quickly eliminated. Besides the Whiting hypothesis, four others are discussed. The new hypothesis of genomic imprinting, of Beukeboom, is eliminated since: a) spermatozoa that develop within the egg produce male tissue; b) telitokous parthenogenesis due to the fusion of two haploid cells develop into females; c) last instar larvae treated with juvenile hormone become queens. The Cunha and Kerr hypothesis (female determining genes are totally or partially additive and male determination is totally or partially nonadditive) explains all known cases. The xo is a female determining gene. Sex determination in social bees led to the gradual evolution of two systems of caste determination: one in which queens and workers are similar and males are very different (Apinae), and another in which workers and males are very similar and both very different from the queens (Meliponinae). This second system in stingless bees implies that many of the mutations that improve worker capacities also affect the males that will carry out some activities that in Apis are clearly female ones. Ten of these activities are described.

Molecular cloning of exons II and III of the a-globin major gene from Odontophrynus americanus 2n and 4n (Amphibia, Anura)

The a-globin major genes from diploid and tetraploid Odontophrynus americanus were studied using PCR-based technology. The cloned and sequenced amplified fragments were shown to contain most of the exon II sequences as well as the whole exon III sequence of the a-globin gene. Unexpectedly, intron 2 was entirely absent in the amplified fragments of both 2n and 4n origin. High conservation was observed among the obtained sequences when compared to corresponding sequences from human and Xenopus laevis origin. The possibility that these sequences might be pseudogenes is raised

Cytogenetic study of the genus Saguinus (Callithrichidae, Primates)

Eight subspecies from the genus Saguinus (S. fuscicollis fuscicollis, S. fuscicollis weddelli, S. bicolor bicolor, S. bicolor martinsi, S. mystax mystax, S. imperator imperator, S. midas midas, and S. midas niger) were studied. Five of them (S. f. fuscicollis, S. f. weddelli, S. b. martinsi, S. m. mystax and S. i. imperator) had their karyotypes described for the first time. Conventional coloration, banding patterns G, C and NOR, and G/C sequential banding tecniques were used. All samples showed the same diploid number (2n = 46). The patterns of the G, C and NOR bands were very similar with little differences in the quantity and constitutive heterochromatin distribution of the autosomes. Constitutive heterochromatin was observed only in telomeric regions of some chromosomes of S. f. fuscicollis and S. f. weddelli. The X chromosome was the same in all subspecies, but chromosome Y differed in size and morphology. XX/XY chimerism was verified in all subspecies

Karyological, biochemical, and physiological aspects of Callophysus macropterus (Siluriformes, Pimelodidae) from the Solimões and Negro Rivers (Central Amazon)

Karyological characteristics, i.e., diploid number, chromosome morphology and nucleolus organizer regions (NORs), biochemical characteristics, i.e., electrophoretic analysis of blood hemoglobin and the tissue enzymes lactate dehydrogenase (LDH), malate dehydrogenase (MDH), alcohol dehydrogenase (ADH), and phosphoglucose isomerase (PGI), and physiological characteristics, i.e., relative concentration of hemoglobin and intraerythrocytic concentrations of organic phosphates were analyzed for the species Callophysus macropterus collected from Marchantaria Island (white water system - Solimões River) and Anavilhanas Archipelago (black water system - Negro River). Karyological and biochemical data did not reveal significant differences between specimens collected at the two sites. However, the relative distribution of hemoglobin bands I and III (I = 16.33 ± 1.05 and III = 37.20 ± 1.32 for Marchantaria specimens and I = 6.33 ± 1.32 and III = 48.05 ± 1.55 for Anavilhanas specimens) and levels of intraerythrocytic GTP (1.32 ± 0.16 and 2.76 ± 0.18 for Marchantaria and Anavilhanas specimens, respectively), but not ATP or total phosphate, were significantly different, indicating a physiological adaptation to the environmental conditions of these habitats. It is suggested that C. macropterus specimens from the two collecting sites belong to a single population, and that they adjusted some physiological characteristics to adapt to local environmental conditions.

Histopathological characteristics of a novel knock-in mouse prostate cancer model

Prostate cancer is relatively unique to man. There is no naturally occurring prostate cancer in the mouse. Pre-clinical studies involve the establishment of a genetically engineered mouse prostate cancer model with features close to those of the human situation. A new knock-in mouse adenocarcinoma prostate (KIMAP) model was established, which showed close-to-human kinetics of tumor development. In order to determine if the similar kinetics is associated with heterogeneous tumor architecture similar to the human situation, we utilized a new mouse histological grading system (Gleason analogous grading system) similar to the Gleason human grading system and flow cytometry DNA analysis to measure and compare the adenocarcinoma of the KIMAP model with human prostate cancer. Sixty KIMAP prostate cancer samples from 60 mice were measured and compared with human prostate cancer. Flow cytometry DNA analysis was performed on malignant prostate tissues obtained from KIMAP models. Mice with prostate cancer from KIMAP models showed a 53.3% compound histological score rate, which was close to the human clinical average (50%) and showed a significant correlation with age (P = 0.001). Flow cytometry analyses demonstrated that most KIMAP tumor tissues were diploid, analogous to the human situation. The similarities of the KIMAP mouse model with tumors of the human prostate suggest the use of this experimental model to complement studies of human prostate cancer.

Pharmacology and toxicology of diphenyl diselenide in several biological models

The pharmacology of synthetic organoselenium compounds indicates that they can be used as antioxidants, enzyme inhibitors, neuroprotectors, anti-tumor and anti-infectious agents, and immunomodulators. In this review, we focus on the effects of diphenyl diselenide (DPDS) in various biological model organisms. DPDS possesses antioxidant activity, confirmed in several in vitro and in vivo systems, and thus has a protective effect against hepatic, renal and gastric injuries, in addition to its neuroprotective activity. The activity of the compound on the central nervous system has been studied since DPDS has lipophilic characteristics, increasing adenylyl cyclase activity and inhibiting glutamate and MK-801 binding to rat synaptic membranes. Systemic administration facilitates the formation of long-term object recognition memory in mice and has a protective effect against brain ischemia and on reserpine-induced orofacial dyskinesia in rats. On the other hand, DPDS may be toxic, mainly because of its interaction with thiol groups. In the yeast Saccharomyces cerevisiae, the molecule acts as a pro-oxidant by depleting free glutathione. Administration to mice during cadmium intoxication has the opposite effect, reducing oxidative stress in various tissues. DPDS is a potent inhibitor of d-aminolevulinate dehydratase and chronic exposure to high doses of this compound has central effects on mouse brain, as well as liver and renal toxicity. Genotoxicity of this compound has been assessed in bacteria, haploid and diploid yeast and in a tumor cell line.

Effects of the conditioned medium of mesenchymal stem cells on mouse oocyte activation and development

Mesenchymal stem cells (MSCs) have been reported to secrete a variety of cytokines and growth factors acting as trophic suppliers, but little is known regarding the effects of conditioned medium (CM) of MSCs isolated from femurs and tibias of mouse on the artificial activation of mouse oocytes and on the developmental competence of the parthenotes. In the current study, we investigated the effect of CM on the events of mouse oocyte activation, namely oscillations of cytosolic calcium concentration ([Ca²+]i), meiosis resumption, pronucleus formation, and parthenogenetic development. The surface markers of MSCs were identified with a fluorescence-activated cell sorter. The dynamic changes of the spindle and formation of pronuclei were examined by laser-scanning confocal microscopy. Exposure of cumulus-oocyte complexes to CM for 40 min was optimal for inducing oocyte parthenogenetic activation and evoking [Ca²+]i oscillations similar to those evoked by sperm (95 vs 100%; P > 0.05). Parthenogenetically activated oocytes immediately treated with 7.5 µg/mL cytochalasin B (CB), which inhibited spindle rotation and second polar body extrusion, were mostly diploid (93 vs 6%, P < 0.01) while CB-untreated oocytes were mostly haploid (5 vs 83%, P < 0.01). Consequently, the blastocyst rate was higher in the CB-treated than in the CB-untreated oocytes. There was no significant difference in developmental rate between oocytes activated with CM and 7% ethanol (62 vs 62%, P > 0.05), but the developmental competence of the fertilized oocytes was superior to that of the parthenotes (88 vs 62%, P < 0.05). The present results demonstrate that CM can effectively activate mouse oocytes, as judged by the generation of [Ca²+]i oscillations, completion of meiosis and parthenogenetic development.