Unbeatable strategy, constraint and coevolution, or how to resolve evolutionary conflicts: the case of the fig/wasp mutualism

Constraints and evolution are central for the resolution of conflicts between mutualistic species and for the stability of mutualisms. However, proximal causes of the benevolence of mutualistic species are often unknown. Monoecious fig species and their specific pollinators are in conflict on the use of fig ovaries, which can either produce one seed or host one pollinator larva. Here, I provide new data showing that, probably because of space constraints during the development of both seeds and wasps, ovaries vary in their quality as a substrate for pollinator development depending on their location within the fig inflorescence. This constraint may be responsible for the stability of the fig/wasp mutualism. Moreover, population density of pollinators and density dependent selection on the pollinators could be sufficient to explain the observed highly variable seed/wasp ratios produced by figs.     

Identification of pathogenic fungi in surgical and autopsy specimens by immunofluorescence

Summary A method is presented for the preparation of immune sera and detection by immunofluorescence ofC. immitis, S. schenckii, B. dermatitidis, C. neoformans, andC. albicans in surgical and autopsy material. Formalin fixation does not affect the antigens of the mycotic agents. There are no cross reactions except withC. immitis andC. neoformans, which can be differentiated by the site of the specific fluorescence in each organism.     

EDC3 phosphorylation regulates growth and invasion through controlling P‐body formation and dynamics

Regulation of mRNA stability and translation plays a critical role in determining protein abundance within cells. Processing bodies (P‐bodies) are critical regulators of these processes. Here, we report that the Pim1 and 3 protein kinases bind to the P‐body protein enhancer of mRNA decapping 3 (EDC3) and phosphorylate EDC3 on serine (S)161, thereby modifying P‐body assembly. EDC3 phosphorylation is highly elevated in many tumor types, is reduced upon treatment of cells with kinase inhibitors, and blocks the localization of EDC3 to P‐bodies. Prostate cancer cells harboring an EDC3 S161A mutation show markedly decreased growth, migration, and invasion in tissue culture and in xenograft models. Consistent with these phenotypic changes, the expression of integrin β1 and α6 mRNA and protein is reduced in these mutated cells. These results demonstrate that EDC3 phosphorylation regulates multiple cancer‐relevant functions and suggest that modulation of P‐body activity may represent a new paradigm for cancer treatment.     

When figs wait for pollinators: the length of fig receptivity

In plant species with an obligate species-specific pollinator, gamete encounter is a critical phase in the success of reproductive strategies. One of the key factors in the success of gamete encounter, the length of female receptivity, has been rarely studied experimentally. In Ficus species (Moraceae), each exclusively associated with its specific pollinating wasp, the receptive female phase of individual syconia was believed to last only a few days. This estimate, based on field observations of pollinator arrivals, neglected the possibility that unpollinated syconia may remain receptive for a prolonged period. In two distantly related fig species (F. carica and F. aurea), we measured experimentally the duration of receptivity of individual syconia protected from pollinator visits. For these two species, receptivity lasted from 2 to 3 wk. Syconia pollinated at any time during this period of receptivity are capable of setting seeds. Furthermore, it has been assumed that female syconium receptivity stops quickly after pollinator visitation. Our experiments showed that syconia of both species are able to extend their receptive period for a few days longer when visited only by a single wasp. The demonstration of a long duration of female receptivity has important consequences for understanding the maintenance of the fig-wasp mutualism.