Transcriptome analysis of Anastrepha fraterculus sp. 1 males, females, and embryos: insights into development, courtship, and reproduction

BACKGROUND

Anastrepha fraterculus sp. 1 is considered a quarantine pest in several American countries. Since chemical control applied in an integrated pest management program is the only strategy utilized against this pest, the development of pesticide-free methods, such as the Sterile Insect Technique, is being considered. The search for genes involved in sex-determination and differentiation, and in metabolic pathways associated with communication and mating behaviour, contributes with key information to the development of genetic control strategies. The aims of this work were to perform a comprehensive analysis of A. fraterculus sp. 1 transcriptome and to obtain an initial evaluation of genes associated with main metabolic pathways by the expression analysis of specific transcripts identified in embryos and adults.

RESULTS

Sexually mature adults of both sexes and 72 h embryos were considered for transcriptome analysis. The de novo transcriptome assembly was fairly complete (62.9% complete BUSCO orthologs detected) with a total of 86,925 transcripts assembled and 28,756 GO annotated sequences. Paired-comparisons between libraries showed 319 transcripts differently expressed between embryos and females, 1242 between embryos and males, and 464 between sexes. Using this information and genes searches based on published studies from other tephritid species, we evaluated a set of transcripts involved in development, courtship and metabolic pathways. The qPCR analysis evidenced that the early genes serendipity alpha and transformer-2 displayed similar expression levels in the analyzed stages, while heat shock protein 27 is over-expressed in embryos and females in comparison to males. The expression of genes associated with courtship (takeout-like, odorant-binding protein 50a1) differed between males and females, independently of their reproductive status (virgin vs mated individuals). Genes associated with metabolic pathways (maltase 2-like, androgen-induced gene 1) showed differential expression between embryos and adults. Furthermore, 14,262 microsatellite motifs were identified, with 11,208 transcripts containing at least one simple sequence repeat, including 48% of di/trinucleotide motifs.

CONCLUSION

Our results significantly expand the available gene space of A. fraterculus sp. 1, contributing with a fairly complete transcript database of embryos and adults. The expression analysis of the selected candidate genes, along with a set of microsatellite markers, provides a valuable resource for further genetic characterization of A. fraterculus sp. 1 and supports the development of specific genetic control strategies.

Isochromosome 17q as a sole anomaly: a distinct myelodysplastic syndrome entity?

We report four patients with myelodysplastic syndrome (MDS) with isochromosome i(17q) as the sole chromosomal anomaly. One patient was classified as refractory anemia (RA) and three as refractory anemia with excess of blasts (RAEB). All four patients shared several features such as male sex, advanced age, severe anemia, as well as a bone marrow with myeloproliferative characteristics: hypercellularity, prominent baso- and eosinophilia, and marked increase of micromegakaryocytes. We suggest that patients with i(17q) as the sole chromosomal anomaly may identify a distinct MDS with characteristics between MDS and chronic myeloproliferative disorders (CMPD).

Ph-positive chronic myeloid leukemia mimicking essential thrombocythemia and terminating into megakaryoblastic blast crisis: report of two cases with molecular studies

Two patients with chronic myeloid leukemia (CML) presenting with the hematologic features of essential thrombocythemia (ET) are reported. At diagnosis they showed extremely high platelet counts (4985 and 2800 x 10(9)/l, respectively) and moderate leukocytosis (21 and 17 x 10(9)/l, respectively). In both cases, in addition to the Philadelphia chromosome (Ph), a rearrangement within the major breakpoint cluster region on chromosome 22 was demonstrated, with the breakpoint in the 3' extreme. In patient 1 the disease initially responded to radioactive phosphorus and hydroxyurea, but during the evolutive course a progressive increase in the white blood cell counts was noted, reaching values typical of the chronic phase of CML, and the patient eventually died from blast crisis 45 months after diagnosis. In patient 2, although good control of the platelet counts was achieved with hydroxyurea, the disease also evolved into a blast crisis four months after diagnosis. In both cases monoclonal antibodies and electron microscopy studies demonstrated the megakaryocytic nature of the blast cells. The above features are not consistent with the present and similar cases being Ph-positive ET. Instead, they should be regarded as a special form of CML characterized by a marked protagonism of the megakaryocytic component.

Cardiac tamponade as the initial manifestation of acute leukemia: report of a case and review of the literature

An 18-year-old woman with acute monoblastic leukemia presenting with cardiac tamponade is reported. Subxiphoid pericardiotomy was performed, and blast cells were observed in the pericardial fluid. The leukemia was refractory to chemotherapy and the patient died at three months from diagnosis, without recurrence of the pericardial effusion. In the review of the literature, only ten cases of cardiac tamponade as the first manifestation of acute leukemia have been found.

Abnormal chromatin clumping in leucocytes: a clue to a new subtype of myelodysplastic syndrome

We report 6 patients with myelodysplastic syndrome, all of whom showed a bizarre nuclear anomaly within the neutrophils that was characterized by extensive clumping of chromatin into large blocks separated by clear zones, generally associated with a lack of segmentation. Anaemia, thrombocytopenia, variable leucocyte counts with leucoerythroblastic picture, marrow hypercellularity with granulocytic hyperplasia and moderate dysplastic changes in erythroblastic and megakaryocytic lines were present at diagnosis. 2 patients had normal karyotypes and a 3 showed a deletion of chromosome 14. 5 out of 6 patients had pneumonia at diagnosis. The median survival was short (5 months) and haemorrhagic complications were the cause of death in 4 patients. The clinical features and the evolution of these and other reported cases suggest that the presence of abnormal chromatin clumping in leucocytes might be a clue to a new subtype of myelodysplastic syndrome.