Effects of Floral Scents and Their Dietary Experiences on the Feeding Preference in the Blowfly, Phormia regina

AbstractThe flowers of different plant species have diverse scents with varied chemical compositions. Hence, every floral scent does not uniformly affect insect feeding preferences. The blowfly, Phormia regina, is a nectar feeder, and when a fly feeds on flower nectar, its olfactory organs, antennae, and maxillary palps are exposed to the scent. Generally, feeding preference is influenced by food flavor, which relies on both taste and odor. Therefore, the flies perceive the sweet taste of nectar and the particular scent of the flower simultaneously, and this olfactory information affects their feeding preference. Here, we show that the floral scents of 50 plant species have various effects on their sucrose feeding motivation, which was evaluated using the proboscis extension reflex (PER). Those floral scents were first categorized into three groups, based on their effects on the PER threshold sucrose concentration, which indicates whether a fly innately dislikes, ignores, or likes the target scent. Moreover, memory of olfactory experience with those floral scents during sugar feeding influenced the PER threshold. After feeding on sucrose solutions flavored with floral scents for 5 days, the scents did not consistently show the previously observed effects. Considering such empirical effects of scents on the PER threshold, we categorized the effects of the 50 tested floral scents on feeding preference into 16 of all possible 27 theoretical types. We then conducted the same experiments with flies whose antennae or maxillary palps were ablated prior to PER test in a fly group naïve to floral scents and prior to the olfactory experience during sugar feeding in the other fly group in order to test how these organs were involved in the effect of the floral scent. The results suggested that olfactory inputs through these organs play different roles in forming or modifying feeding preferences. Thus, our study contributes to an understanding of underlying mechanisms associated with the convergent processing of olfactory inputs with taste information, which affects feeding preference or appetite

Phenotypic Characterization of Transgenic Mice Overexpressing Neuregulin-1

BACKGROUND: Neuregulin-1 (NRG1) is one of the susceptibility genes for schizophrenia and implicated in the neurotrophic regulation of GABAergic and dopaminergic neurons, myelination, and NMDA receptor function. Postmortem studies often indicate a pathologic association of increased NRG1 expression or signaling with this illness. However, the psychobehavioral implication of NRG1 signaling has mainly been investigated using hypomorphic mutant mice for individual NRG1 splice variants. METHODOLOGY/PRINCIPAL FINDINGS: To assess the behavioral impact of hyper NRG1 signaling, we generated and analyzed two independent mouse transgenic (Tg) lines carrying the transgene of green fluorescent protein (GFP)-tagged type-1 NRG1 cDNA. The promoter of elongation-factor 1α gene drove ubiquitous expression of GFP-tagged NRG1 in the whole brain. As compared to control littermates, both heterozygous NRG1-Tg lines showed increased locomotor activity, a nonsignificant trend toward decreasing prepulse inhibition, and decreased context-dependent fear learning but exhibited normal levels of tone-dependent learning. In addition, social interaction scores in both Tg lines were reduced in an isolation-induced resident-intruder test. There were also phenotypic increases in a GABAergic marker (parvalbumin) as well as in myelination markers (myelin basic protein and 2',3'-cyclic nucleotide 3'-phosphodiesterase) in their frontal cortex, indicating the authenticity of NRG1 hyper-signaling, although there were marked decreases in tyrosine hydroxylase levels and dopamine content in the hippocampus. CONCLUSIONS: These findings suggest that aberrant hyper-signals of NRG1 also disrupt various cognitive and behavioral processes. Thus, neuropathological implication of hyper NRG1 signaling in psychiatric diseases should be evaluated with further experimentation

Structural and Functional Modulations of RNApolymerase During Growth Phase Transition ofEscherichia coli

　　During the growth phase transition of Escherichia coli from exponential growth to stationary phase, the pre-existing RNA polymerase was found to be converted into at least three different holoenzyme forms, which could be isolated by phosphocellulose column chromatography (Ozaki, M., et al. (1991) Mol. Gen. Genet. 230, 17-24).　The relative levels of these three holoenzyme forms changed depending on the phase of cell growth. In the in vitro mixed transcription assay using 33 different E. coli promoters, one of the stationary-phase RNA polymerase, S1, showed promoter recognition properties which are significantly different from that of holoenzyme from exponentially growing cells. 　　Enzyme reconstitution experiments showed that the altered promoter selectivity is due to alteration in core enzyme. After a variety of attempts to achieve in vitro interconversion between the exponential and the stationary phase RNA polymerases, S1-form enzyme was found to be converted in vitro into such an enzyme as the log-phase form, following incubation with nucleotides or pyrophosphate (Ozaki, M. et al., (1991) Nucleic Acids Res. in press). The conversion was indicated by not only the shift of elution position from a phosphocellulose column but also the change in the promoter selectivity. Using polyphosphate kinase (PPK) which polymerizes the terminal phosphate of ATP to a long chain polyphosphate in a freely reversible reaction, polyphosphate was detected in the stationary-phase RNA polymerase (Ozakl, M. et al., in preparation). These results altogether lead to the possibility that RNA polymerase is converted into the stationary-phase form by binding polyphosphate. I propose that the modulation of RNA polymerase by polyphosphate plays a role in the global switch of gene transcription during the growth transition of E. coli to stationary phase

Influence of filtering on the effective concentration and sterility of a 2% cyclosporine ophthalmic solution: a quality improvement perspective

Abstract Background Pharmaceutical companies do not sell formulations for all diseases; thus, healthcare workers have to treat some diseases by concocting in-hospital preparations. An example is the high-concentration 2% cyclosporine A (CyA) ophthalmic solution. Utilizing a filter in sterility operations is a general practice for concocting in-hospital preparations, as is the case for preparing a 2% CyA ophthalmic solution. However, whether filtering is appropriate concerning the active ingredient content and bacterial contamination according to the post-preparing quality control of a 2% CyA ophthalmic solution is yet to be verified. Methods We conducted particle size, preparation concentration, and bacterial contamination studies to clarify aforementioned questions. First, we measured the particle size of CyA through a laser diffraction particle size distribution. Next, we measured the concentration after preparation with or without a 0.45-µm filter operation using an electrochemiluminescence immunoassay. Finally, bacterial contamination tests were conducted using an automated blood culture system to prepare a 2% CyA ophthalmic solution without a 0.45 μm filtering. Regarding the pore size of the filter in this study, it was set to 0.45 μm with reference to the book (the 6th edition) with recipes for the preparation of in-hospital preparations edited by the Japanese Society of Hospital Pharmacists. Results CyA had various particle sizes; approximately 30% of the total particles exceeded 0.45 μm. The mean ± standard deviation of filtered and non-filtered CyA concentrations in ophthalmic solutions were 346.51 ± 170.76 and 499.74 ± 76.95ng/mL, respectively (p = 0.011). Regarding bacterial contamination tests, aerobes and anaerobes microorganisms were not detected in 14 days of culture. Conclusions Due to the results of this study, the concentration of CyA may be reduced by using a 0.45-µm filter during the preparation of CyA ophthalmic solutions, and furthermore that the use of a 0.45-µm filter may not contribute to sterility when preparing CyA ophthalmic solutions