No abstract

Parental care behavior evolves to increase the survival of offspring. When offspring care becomes complicated for ecological reasons, cooperation of multiple individuals can be beneficial. There are two types of cooperative care: biparental care and worker (helper)-based care (e.g., eusociality). Although biparental care is common in several groups of vertebrates, it is generally rare in arthropods. Conversely, eusociality is widespread in insects, especially the aculeate Hymenoptera. Here, we present a case of biparental care in bees, inCeratina nigrolabiata(Apidae, Xylocopinae). Similar to eusocial behavior, biparental care leads to greater brood protection in this species. Male guarding increases provisioning of nests because females are liberated from the tradeoff between provisioning and nest protection. The main benefit of parental care for males should be increased paternity. Interestingly though, we found that paternity of offspring by guard males is extraordinarily low (10% of offspring). Generally, we found that nests were not guarded by the same male for the whole provisioning season, meaning that males arrive to nests as stepfathers. However, we show that long-term guarding performed by a single male does increase paternity. We suggest that the multiple-mating strategy of these bees increased the amount of time for interactions between the sexes, and this longer period of potential interaction supported the origin of biparental care. Eusociality based on monandry was thought to be the main type of extended brood protection in bees. We show that biparental care based on polyandry provides an interesting evolutionary alternative.

We performed a 2-DE analysis of proteins of the newly established spontaneously immortalized clonal cell line EM-G3 derived from a primary lesion of infiltrating ductal breast carcinoma. EM-G3 cells may represent progenitors of the mammary epithelial cells spontaneously immortalized in early phase of cancerogenesis. We compared the protein profile of EM-G3 line with proteins from populations of normal mammary epithelial cells (NME), and determined the phenotype of both types of cells. NME cells are a mixture of both main cell types in breast epithelia, myoepithelial and luminal cells. The EM-G3 breast cancer cell line has a unique basal-like phenotype. We identified proteins that are differently expressed in these cells. Cytokeratin 16, cytokeratin 19, squamous cell carcinoma antigen 1, caphepsin B and caspase 14 were predominantly expressed by NME cells. Cytokeratin 13, isoelectric variant of annexin 5, isoelectric variant of chloride intracellular channel protein 1, glyoxalase 1 and glutamine synthetase were predominantly expressed by EM-G3 cells. The proteins up-regulated in EM-G3 cells may represent potential protein markers of mammary epithelial cells progenitors and may be important in early phase of carcinogenesis.

Biological meshes are biomaterials consisting of extracellular matrix that are used in surgery particularly for hernia treatment, thoracic wall reconstruction, or silicone implant-based breast reconstruction. We hypothesized that combination of extracellular matrices with autologous mesenchymal stem cells used for hernia repair would result in increased vascularization and increased strength of incorporation. We cultured autologous adipose-derived stem cells harvested from the inguinal region of Wistar rats on cross-linked and noncross-linked porcine extracellular matrices. In 24 Wistar rats, a standardized 2×4 cm fascial defect was created and repaired with either cross-linked or noncross-linked grafts enriched with stem cells. Non-MSC-enriched grafts were used as controls. The rats were sacrificed at 3 months of age. The specimens were examined for the strength of incorporation, vascularization, cell invasion, foreign body reaction, and capsule formation. Both materials showed cellular ingrowth and neovascularization. Comparison of both tested groups with the controls showed no significant differences in the capsule thickness, foreign body reaction, cellularization, or vascularization. The strength of incorporation of the stem cell-enriched cross-linked extracellular matrix specimens was higher than in acellular specimens, but this result was statistically nonsignificant. In the noncross-linked extracellular matrix, the strength of incorporation was significantly higher in the stem cell group than in the acellular group. Seeding of biological meshes with stem cells does not significantly contribute to their increased vascularization. In cross-linked materials, it does not ensure increased strength of incorporation, in contrast to noncross-linked materials. Owing to the fact that isolation and seeding of stem cells is a very complex procedure, we do not see sufficient benefits for its use in the clinical setting.