On-line state recognition in a yeast fed-batch culture using error vectors

The physiological states with respect to cell growth and ethanol production in a yeast fed-batch culture expressed in linguistic form could be recognized on-line by fuzzy inferencing based on error vectors. The error vector was newly defined here in a macroscopic elemental balance equation. The physiological states for cell growth and ethanol production were characterized by error vectors using many experimental data from fed-batch cultures. Fuzzy membership functions were constructed from the frequency distributions of the error vectors and state recognition was performed by fuzzy inferencing. In particular, an unusual physiological state for a yeast cultivation, in which aerobic ethanol production was accompanied by very low cell growth, could be recognized accurately. According to the results of the state recognition, an energy parameter, the P/O ratio in the metabolic reaction model was adaptively estimated, and the cell growth was successfully evaluated with the estimated P/O. (c) 1995 John Wiley & Sons, Inc.     

Natsumushi: Image measuring software for entomological studies

Natsumushi is a free image analysis software that offers easy handling and quick measurement, designed especially for entomologists as the main users. The software enables measurement of: (i) color features of a specific region; (ii) area size; (iii) length of simple lines or polylines; and (iv) number of points or their x–y coordinates. Users can specify the region for measurement either manually or automatically by using image thresholding operations. The software is freely available at the website https://staff.aist.go.jp/t-fukatsu/Natsumushi.html .     

Factors regulating predation by first-instar spined assassin bugs [Sinea diadema (Fabricius)] (Hemiptera: Reduviidae)

Selected nutritional and developmental factors regulating the predatory behavior of first-instar spined assassin bugsSinea diadema (Fabricius) (Hemiptera: Reduviidae) were investigated. The longevity of unfed nymphs provided with free water, bean pod sections, or glucose solutions was not significantly greater than that of unfed nymphs which were not provided with a source of water. First-instarS. diadema that were provided with larvae ofEphestia kuehniella Zeller (Lepidoptera: Pyralidae) as prey began feeding 1.9 (±0.9) days after hatching. In contrast, first-instarS. diadema that were provided with conspecifics of the same age did not begin feeding until they were 3.9 (±0.9) days old. These results suggest that the potential nutritional benefits to be gained from feeding equal or outweigh the risk of attacking prey capable of effective self-defense only when nymphs have not fed for 4 days after hatching. Providing the nymphs with water or glucose solutions significantly delayed the onset of conspecific predation. Additional data are presented which demonstrate that first-instarS. diadema are not restrained from preying on siblings by kin recognition.     

Novel object exploration in mice: not all objects are created equal

Object exploration is an increasingly popular experimental paradigm in behavioral sciences. We have begun a series of studies with mice specifically looking at the parameters that influence behaviors in this test. The aim of the present study was to examine the effect of object type on performance in the object exploration test. More specifically, adult male C57BL/6J mice were trained and tested using objects that could be climbed (CLIMB) or with those that could only be touched (TOUCH). The results show that activity is affected by the presentation of objects, with object type interacting with some of these changes. C57 mice explored objects that can be climbed over significantly longer than objects that can only be touched and a more rapid habituation was observed using objects that could only be touched. Robust recognition memory was observed in both groups of mice, however mice in the CLIMB group exhibited a significantly greater discrimination index compared to mice in the TOUCH group. Taken together, these findings demonstrate that the selection of objects is of critical importance and it is recommended that special attention be given to the functional (affordant) properties of the objects to-be-used in future studies.     

THE GENETIC BASIS OF ZEBRA FINCH VOCALIZATIONS

Animal vocalizations play an important role in individual recognition, kin recognition, species recognition, and sexual selection. Despite much work in these fields done on birds virtually nothing is known about the heritability of vocal traits in birds. Here, we study a captive population of more than 800 zebra finches ( Taeniopygia guttata ) with regard to the quantitative genetics of call and song characteristics. We find very high heritabilities in nonlearned female call traits and considerably lower heritabilities in male call and song traits, which are learned from a tutor and hence show much greater environmental variance than innate vocalizations. In both sexes, we found significant heritabilities in several traits such as mean frequency and measures of timbre, which reflect morphological characteristics of the vocal tract. These traits also showed significant genetic correlations with body size, as well as positive genetic correlations between the sexes, supporting a scenario of honest signaling of body size through genetic pleiotropy ("index signal"). In contrast to such morphology-related voice characteristics, classical song features such as repertoire size or song length showed very low heritabilities. Hence, these traits that are often suspected to be sexually selected would hardly respond to current directional selection.     

Alanine scanning mutational analysis of the ligand binding pocket of the human Vitamin D receptor

We achieved exhaustive alanine scanning mutational analysis of the amino acid residues lining the ligand binding pocket of the Vitamin D receptor to investigate the mechanism of the ligand recognition by the receptor. This is the first exhaustive analysis in the nuclear receptor superfamily. Our results demonstrated the role and importance of all the residues lining the ligand binding pocket. In addition, this analysis was found to indicate ligand-specific ligand-protein interactions, which have key importance in determining the transactivation potency of the individual ligands. Thus, the analysis using 1beta-methyl-1alpha,25-dihydroxyvitamin D(3) revealed the specific van der Waals interactions of 1beta-methyl group with the receptor.     

Plant volatiles mediate attraction to host and non-host plant in apple fruit moth, Argyresthia conjugella

Plant volatiles mediate host finding in insect herbivores and lead to host fidelity and habitat‐specific mating, generating premating reproductive isolation and facilitating sympatric divergence. The apple fruit moth, Argyresthia conjugella Zeller (Lepidoptera: Argyresthiidae), is a particularly suitable species to study the cues and behavioural mechanisms leading to colonization of a new host: it recurrently oviposits on the non‐host plant, apple Malus domestica Borkh. (Rosaceae), where the larvae cannot complete their development. The larval host of the apple fruit moth (Lepidoptera, Argyresthiidae), is rowan Sorbus aucuparia L. (Rosaceae). Fruit setting in rowan, however, fluctuates strongly over large areas in Scandinavia. Every 2–4 years, when too few rowanberries are available for egg laying in forests, apple fruit moth females oviposit instead on apple in nearby orchards, but not on other fruits, such as pear or plum. This poses the question of which cues mediate attraction to rowan and apple, and how apple fruit moth discriminates rowan from apple. Chemical analysis and antennal recordings showed that 11 out of 15 rowan volatiles eliciting an antennal response in A. conjugella females co‐occur in rowan and apple headspace, in a different proportion. In the field, A. conjugella was attracted to several of these plant volatiles, especially to 2‐phenyl ethanol, methyl salicylate, and decanal. Addition of anethole to 2‐phenyl ethanol had a strong synergistic effect, the 1 : 1 blend is a powerful attractant for A. conjugella males and females. These results confirm that volatiles common to both plants may account for a host switch in A. conjugella from rowan to apple. Some of the most attractive compounds, including 2‐phenyl ethanol, anethole, and decanal, which have been found in several apple cultivars, were not present in the headspace of the apple cultivar, Aroma, which is also susceptible to attack by A. conjugella. This supports the idea that the odour signal from apple is suboptimal for attraction of A. conjugella, but is nonetheless sufficient for attraction, during times when rowan is not available for egg laying.     

Distribution and Pharmacological Properties of the GABAA/ Benzodiazepine/Chloride Ionophore Receptor Complex in the Brain of the Fish Anguilla anguilla

In the present study, we characterized the distribution and the pharmacological properties of the different components of the GABAA receptor complex in the brain of the eel (Anguilla anguilla). Benzodiazepine recognition sites labeled "in vitro" with [3H]flunitrazepam ([3H]FNT) were present in highest concentration in the optic lobe and in lowest concentration in the medulla oblongata and spinal cord. A similar distribution was observed in the density of gamma-[3H]aminobutyric acid ([3H]GABA) binding sites. GABA increased the binding of [3H]FNT in a concentration-dependent manner, with a maximal enhancement of 45% above the control value, and, vice versa, diazepam stimulated the binding of [3H]GABA to eel brain membrane preparations. The density of benzodiazepine and GABA recognition sites and their reciprocal regulation were similar to those observed in the rat brain. In contrast, the binding of the specific ligand for the Cl- ionophore, t-[35S]butylbicyclophosphorothionate ([35S]TBPS), to eel brain membranes was lower than that found in the rat brain. In addition, [35S]TBPS binding in eel brain was less sensitive to the inhibitory effects of GABA and muscimol and much more sensitive to the stimulatory effect of bicuculline, when compared with [35S]TBPS binding in the rat brain. Moreover, the uptake of 36Cl- into eel brain membrane vesicles was only marginally stimulated by concentrations of GABA or muscimol that significantly enhanced the 36Cl- uptake into rat brain membrane vesicles. Finally, intravenous administration of the beta-carboline inverse agonist 6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylic acid methyl ester (20 mg/kg) and of the chloride channel blocker pentylenetetrazole (80 mg/kg) produced convulsions in eels that were antagonized by diazepam at doses five to 20 times higher than those required to produce similar effects in rats. The results may indicate a different functional activity of the GABA-coupled chloride ionophore in the fish brain as compared with the mammalian brain.