The International journal of developmental biology
-
This review summarizes recent advances in leg regeneration research, focusing on the cricket Gryllus bimaculatus. Recent studies have revealed molecular mechanisms on blastema formation, establishment of positional information, and epigenetic regulation during leg regeneration. Especially, these studies have provided molecular bases in classical conceptual models such as the polar coordinate model, the intercalation model, the boundary model, the steepness model, etc., which were proposed to interpret regeneration processes of the cockroach legs. ⋯ For the molecular mechanism of intercalation of the missing structures between the amputated position and the most distal one, Dachsous/Fat (Ds/Ft) steepness model has been proposed, in which the Ds/Ft pathway maintains positional information and determines leg size through dac expression. This model was theoretically verified to interpret the experimental results obtained with cricket legs. Availability of whole-genome sequence information, regeneration-dependent RNA interference, and genome editing technique will have the cricket be an ideal model system to reveal gene functions in leg regeneration.
-
Embryonic stem (ES) cells are pluripotent cells derived from the inner cell mass of the blastocyst. These cells can proliferate indefinitely and differentiate into all cell lineages. Germ cell cancers (GCC) mimic embryonic development to a certain extent. ⋯ Therefore, investigation of miRs can shed light on the process of pathogenesis, and may provide biomarkers for diagnosis and prognosis. A subset of miRs is specifically expressed in ES cells and GCC, suggesting their critical role in early embryogenesis and development. In this review we discuss the current view of the biology of embryonic stem cell proteins and miRs in GCC, and their potential clinical impact.
-
It has long been known that estradiol influences synaptic plasticity in the female hippocampus. The density of dendritic spines varies during the estrous cycle and correlates positively with varying levels of estradiol in serum. In accordance, ovariectomy results in a loss of spines that can be rescued by estradiol treatment in animals, suggesting that estradiol originating from the ovaries induces spine formation in the hippocampus. ⋯ This paradigm may also be true in males. In support of this hypothesis, we found that the content of estradiol in hippocampal tissue is higher in female compared to that in male animals, with low levels of estradiol in serum and tonic and acyclical GnRH release. In summary, our data point to important sex-specific differences in sexual steroid-induced synaptogenesis.
-
The sequencing of a Hydra genome marked the beginning of a new era in the use of Hydra as a developmental model. Analysis of the genome sequence has led to a number of interesting findings, has required revisiting of previous work, and most importantly presents new opportunities for understanding the developmental biology of Hydra. This review will de-scribe the history of the Hydra genome project, a selection of results from it that are relevant to developmental biologists, and some future research opportunities provided by Hydra genomics.
-
Portugal celebrated in 2006 its first 20 years of the formal introduction of the practice of external evaluation of research proposals in the national funding system. Accounts of changes in numbers of publications, citations, numbers of research projects funded and budget figures can be found in Government Reports (www.oces.mctes.pt.). ⋯ Reciprocally, the entry of basic biological scientists into medically oriented groups totally changed the landscape, the soil, the seeding, the cross-fertilization and the flowering of biomedical research in the country. This paper is a personal account of the experience of a scientist who was asked by the then President of the National Research Council, Jose Mariano Gago to co-ordinate the introduction of external evaluation of research projects and research institutes in the Health Sciences in Portugal between 1986 and 1997.