Synthesis of protoporphyrin IX induced by 5-aminolevulinic acid in yeast cells in the presence of 2,2;-dipyridyl

5-Aminolevulinic acid (ALA), a precursor of porphyrin synthesis, increased the production of various porphyrin compounds in Candida guilliermondii cells. Metalloporphyrins and protoporphyrin IX (PPIX) were predominantly accumulated, respectively, at ALA concentrations of 0.2-0.4 mM and at those higher than 1.5 mM. 2,2;-Dipyridyl which complexed with bivalent metals significantly increased the content of endogenous PPIX even at ALA concentrations lower than 0.5 mM. Under these conditions, the yeast sensitivity to photodynamic effect of visible light (400-600 nm) dramatically increased due to photosensitization by endogenous PPIX.     

Induction of winged sexuparae in root-inhabiting colonies of the aphid Pemphigus betae

Abstract. Growth chamber experiments were conducted to determine what environmental factors induce the development of sexuparae in root-feeding colonies of the aphid Pemphigus betae Doane (Aphididae: Pemphiginae). Experimental colonies were derived from clones that had been reproducing for at least 15 months under constant laboratory conditions. At constant 20–23^oC, sexuparae were almost never produced regardless of the level of crowding or photoperiod. In contrast, every culture of several clones produced sexuparae when subjected to temperatures alternating between 20 and 15^oC during the light and dark phases respectively. This fluctuating temperature regime resulted in sexupara production regardless of photoperiod. All cultures also produced some sexuparae when cultures were kept in constant darkness at temperatures that were either alternated between 20 and 15^oC or kept constant at 15^oC. Constant 17^oC resulted in sexupara production in most cultures. At 17^oC, experimental manipulation of densities within cultures showed that crowding promotes sexupara production. Thus, within the range of conditions occurring at the time of sexupara induction in the field, photoperiod has no effect on sexupara production, temperature below a threshold between 17 and 20–23^oC triggers sexupara production, and crowding promotes sexupara production but only if temperature is low enough.     

Male accessory gland proteins induce female monogamy in anopheline mosquitoes

The role of male accessory gland (MAG) secretions in inducing refractoriness to further mating in mosquitoes (Diptera: Culicidae) was established in the late 1960s. In a set of simple experiments, MAG extract was injected intra-thoraxically into the hemocoel of virgin Aedes aegypti (L.), Culex pipiens pipiens (L.) and Anopheles quadrimaculatus Say females. This subsequently caused most females to remain unmated when exposed to males. For anophelines these findings were later challenged by a study involving intra-abdominal injections of MAG extracts into Anopheles gambiae Giles s.l. and Anopheles albimanus Wiedmann females, which failed to induce refractoriness to further mating. These findings led to controversy about the respective role of sperm and accessory gland peptides in inducing female monogamy in Anopheles and are at odds with our current understanding of the mating process in Drosophila spp. (Diptera: Drosophillidae) and other dipterans. Here we confirm the function of MAG secretions in anophelines experimentally by showing that intra-thoracic injections in Anopheles stephensi Liston and in the M and S molecular forms of An. gambiae s.s. result in the expected female monogamy. Cross-injections of MAG extracts between the M and S molecular forms of An. gambiae , two cryptic taxa within An. gambiae s.s. which are thought to be undergoing incipient speciation, also elicited effective refractoriness, suggesting that the two sub-taxa have not diverged with regard to sex peptides responsible for female monogamy. Importantly, this also suggests that the rare cases of re-mating following cross-mating observed in this species may not be a form of reproductive barrier between molecular forms.