End Product Inhibition of Serotonin Synthesis in the Rat Striatum

THE synthesis of serotonin (5-HT) in central serotoninergic neurones seems to depend on the intraneuronal concentrations of the amine. After acute or chronic treatment with a monoamine oxidase inhibitor (MAOI), which induced more than a three-fold increase in 5-HT concentrations, we observed a reduced formation of ³H-5-HT from ³H-tryptophan in the rat brain¹. More precisely, this effect could be seen by measuring the accumulation of ³H-5-HT in tissues 15 min after the intracisternal injection of ³H-tryptophan at various times after pheniprazine or pargyline treatments. The ³H-amine accumulation was much less after 3 h than 0.5 h after the MAOI injections. The existence of a 5-HT synthesis regulation by end product inhibition occurring at the first limiting step was proposed to explain these results¹.     

Maternal attendance and the maintenance of family groups in common earwigs (Forficula auricularia): a field experiment

Abstract.  1. Understanding the evolution of subsocial behaviour and parental care requires experimental tests of the functional significance of such behaviours and the role of tending parents in the maintenance of family groups. Studies in subsocial insects addressing these issues experimentally and in the field are still relatively rare.
2. In such a field experiment, it is demonstrated here that the presence of tending females enhances the maintenance of family groups in common earwigs, Forficula auricularia (Dermaptera; Forficulidae). Experimental removal of tending mothers resulted in substantially decreased recovery of occupied nest burrows and larvae. This effect may have been because of decreased survival among experimental larvae, although a possible role for enhanced larval dispersal could not be fully ruled out.
3. Experimental (motherless) larvae were partly observed in family groups with a tending female, in both experimental and control nest burrows, suggesting that these larvae had been adopted by family groups moving to new nest burrows, and/or that experimental larvae may have actively joined other family groups.
4. This study demonstrates under field conditions the functional importance of maternal attendance for the maintenance of family groups in common earwigs, and suggests that adoption and clutch-joining are factors affecting the social structure of this species.     

Phylogenetic analyses of Cloeodes Traver and related genera (Ephemeroptera: Baetidae)

Cloeodes Traver is atypical among Baetidae (Ephemeroptera) because it seems to possess a unique Pantropical distribution. Thirty‐nine species have been described to date, 26 from the Neotropics, four from the Southern Nearctic, seven from the Afrotropics and two from the Oriental region. Several genera have been considered related to Cloeodes during the last decades, of which the following remain valid: Crassabwa Lugo‐Ortiz & McCafferty, Dabulamanzia Lugo‐Ortiz & McCafferty (both Afrotropical), Bungona Harker (Australasian) and Chopralla Waltz & McCafferty (Oriental). Despite their supposed relationship, a phylogenetic analysis between all of these genera has never been performed. In the present paper, based on an extensive analysis of all genera that have been considered related to Cloeodes, a phylogenetic analysis using morphological characters (continuous and discrete) was performed in order to address the monophyly of the genus Cloeodes within the Cloeodes complex of genera. According to our results, Cloeodes and the complex are paraphyletic. Based on this, Cloeodes is restricted to the New World, Potamocloeon is revalidated to include most representatives of Afrotropical Cloeodes and is divided into two subgenera: Potamocloeon (Africa) and the new Aquaediva (Madagascar). In addition, the concept of Bungona is expanded to include Australasian and Oriental taxa – namely the subgenera Chopralla and the revalidated Centroptella – and finally the new genus Crassolus is established to include C. inzingae comb.n. from Africa. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:C416090E-C43D-481A-9A3D-F3B1EEE41176 .     

Bulbing in Long-day Onion (Allium cepa L.) Cultured In Vitro: Comparison Between Sugar Feeding and Light Induction

Bulbs were obtained on onion plants cultured in vitro. No bulbinghappened under long days with fluorescent light and 30–40g l^–1 sucrose. Bulb formation was mainly dependent eitheron sucrose concentration in the culture medium, or on lightspectral composition. Raising the sucrose concentration from40 to 120 g l^–1 increased plant basal swelling and stoppedfurther vegetative development. These plants were not dormant.When fluorescent light was enriched in incandescence duringa long day period, bulbs were obtained in two months and underwenta consecutive dormancy. Bulb, dormancy, light spectral quality, photoperiod, R: FR ratio, sugar, tissue culture     

French mosquito populations invaded by A2-B2 esterases causing insecticide resistance

In the mosquito Culex pipiens L., the two associated esterases A2 and B2 are responsible for resistance to organophosphorus (OP) insecticides in many countries of Africa, Asia and North America. We report here their presence and geographic spread in French populations based on the analysis of 168 samples collected from 1984 to 1990. First detected in 1986 in one sample from southern France, these esterases were progressively found in new geographic locations, so that in 1990 their distribution covered at least four contiguous French regions. RFLP analysis of the amplified B2 gene indicates that A2-B2 arrived in France most likely through migration. This genetic invasion is discussed in the light of the recent occurrence of A2-B2 in the mosquito genome, and of the consequences of this new resistance factor in natural populations already possessing other insecticide resistance genes.