FRL and DAAM are required for lateral adhesion of interommatidial cells and patterning of the retinal floor

Optical insulation of the unit eyes (ommatidia) is an important prerequisite of precise sight with compound eyes. Separation of the ommatidia is ensured by pigment cells that organize into a hexagonal lattice in the Drosophila eye, forming thin walls between the facets. Cell adhesion, mediated by apically and latero-basally located junctional complexes, is crucial for stable attachment of these cells to each other and the basal lamina. Whereas former studies have focused on the formation and remodelling of the cellular connections at the apical region, here, we report a specific alteration of the lateral adhesion of the lattice cells, leaving the apical junctions largely unaffected. We found that DAAM and FRL, two formin-type cytoskeleton regulatory proteins, play redundant roles in lateral adhesion of the interommatidial cells and patterning of the retinal floor. We show that formin-dependent cortical actin assembly is crucial for latero-basal sealing of the ommatidial lattice. We expect that the investigation of these previously unreported eye phenotypes will pave the way toward a better understanding of the three-dimensional aspects of compound eye development.

[Catatonia and neuroleptic malignant syndrome in view of a psychopathological and pathophysiological overlap: a brief review]

Catatonia was first described in the 19th century as a syndrome with motor, affective and behavioral symptoms. During the 20th century it was rather regarded as a rare motoric manifestation of schizophrenia and that classification has almost resulted in the disappearance of catatonia among patients outside of the schizophrenia spectrum. With the introduction of neuroleptics, the incidence of catatonic schizophrenia also declined which was attributed to effective treatment. Simultaneously, neuroleptic malignant syndrome was described, which shows many similarities with catatonia. Recently, several researchers suggested a common origin of the two disorders. In this paper we review case reports of the last five years, in which both neuroleptic malignant syndrome and catatonia had emerged as a diagnosis. Additionally, based on the relevant literature, we propose a common hypothetical pathomechanism with therapeutic implications for the two syndromes. Besides underlining the difficulties of differential diagnosis, the reviewed cases demonstrate a transition between the two illnesses. The similarities and the possible shifts may suggest a neuropathological and pathophysiological overlap in the background of the two syndromes. Electroconvulsive therapy and benzodiazepines seem to be an effective treatment in both syndromes. These two treatment approaches can be highly valuable in clinical practice, especially if one considers the difficulties of differential diagnosis.

[Observations of MDPV users: a prospective-retrospective study]

INTRODUCTION

The spreading of "designer drugs" resulted in the appearance of "similar yet different" substances, the chemical structure of which are modified so regularly, which makes their research very difficult. We came across one of these substances, MDPV, while on night duty before it was mentioned in research papers. Our own research explores the changes in drug consumption patterns, especially in MDPV consumption patterns in the past few years, and gives a description of psychiatric and associated symptoms.

METHOD

We compared cases of patients admitted to our ward between Jan 1., 2010 and November 30., 2012 with symptoms of drug consumption and its complications (BNO F15.00-F15.90, F19.00-F19.90). We examined symptoms that required inpatient care at the psychiatry ward.

RESULTS

While in 2010 we treated only 3 MDPV users on 6 occasions, 4 Mephedrone users on 6 occasions, and 9 patients using other substances (Speed, Cannabis) on 10 occasions at our ward, in 2011 there were no Mephedrone-related hospitalizations and only 9 patients using other substances (Cannabis, Synthetic Cannabinoid, 5-MeO-AMT, Glue, Metamizole, Ketamine) were treated on 13 occasions. Between Jan 1. 2011. and Nov 30.2012 there were 40 recorded cases related to MDPV-use in the period: forty people were registered on 87 occasions. Nine people receive impatient care after observation on 10 occasions. In all these cases psychotic symptoms were recorded.

CONCLUSION

The constant development of designer drugs requires better administration of the individual cases, symptoms and forms of treatments. Informing doctors about these details also seems necessary. We have found that the behaviours of drug users show a positive correspondence with changing legal environments, which calls for a more sensible drug-related policy.

Effects of mutant Drosophila K+ channel subunits on habituation of the olfactory jump response

The olfactory-jump response assay was used to analyze habituation in Drosophila mutants of potassium (K(+)) channel subunits. As with physiological assays of the giant fiber-mediated escape reflex, mutations at loci that encode K(+) channel subunits have distinct effects on habituating the olfactory-jump response. The data for slowpoke and ether à go-go indicate similar effects on habituation of the olfactory-jump response and the giant fiber-mediated escape. Habituation in the olfactory jump assay in Hyperkinetic and Shaker mutants was drastically different from the degree of defect in the giant fiber-mediated escape reflex, indicating differential control mechanisms underlying the two forms of non-associative conditioning.

Dual-tagging gene trap of novel genes in Drosophila melanogaster

A gene-trap system is established for Drosophila. Unlike the conventional enhancer-trap system, the gene-trap system allows the recovery only of fly lines whose genes are inactivated by a P-element insertion, i.e., mutants. In the gene-trap system, the reporter gene expression reflects precisely the spatial and temporal expression pattern of the trapped gene. Flies in which gene trap occurred are identified by a two-step screening process using two independent markers, mini-w and Gal4, each indicating the integration of the vector downstream of the promoter of a gene (dual tagging). mini-w has its own promoter but lacks a polyadenylation signal. Therefore, mini-w mRNA is transcribed from its own promoter regardless of the vector integration site in the genome. However, the eyes of flies are not orange or red unless the vector is incorporated into a gene enabling mini-w to be spliced to a downstream exon of the host gene and polyadenylated at the 3' end. The promoter-less Gal4 reporter is expressed as a fusion mRNA only when it is integrated downstream of the promoter of a host gene. The exons of trapped genes can be readily cloned by vectorette RT-PCR, followed by RACE and PCR using cDNA libraries. Thus, the dual-tagging gene-trap system provides a means for (i) efficient mutagenesis, (ii) unequivocal identification of genes responsible for mutant phenotypes, (iii) precise detection of expression patterns of trapped genes, and (iv) rapid cloning of trapped genes.

Fruitless is in the regulatory pathway by which ectopic mini-white and transformer induce bisexual courtship in Drosophila

Bisexual courtship in male Drosophila melanogaster may be induced in some circumstances. These include ectopic expression of the transformer (tra) gene, ectopic expression of the mini-white (mw) gene, and the homozygous presence of mutant alleles of the fruitless (fru) gene. Experiments were performed to determine if ectopic mw and fru, as well as ectopic tra and fru, acted in the same pathway to control courtship. Male flies homozygous for the frusat allele court females little if at all and males at a low level. When homozygous, the frusat allele suppresses the bisexual courtship induced by both ectopic mw and ectopic tra, indicating that the fru wild-type function is necessary for expression of the ectopic mw and ectopic tra effect. This demonstrates that fru shares a pathway controlling courtship behavior with these ectopically expressed genes.

Sexual behaviour: Courting dissatisfaction

A nuclear receptor, the product of the dissatisfaction gene, has been found to regulate Drosophila sexual behaviour, probably via its action in a small subset of neurons. The results shed new light on the genetic determination of sexual behaviour.

The Drosophila melanogaster 60A chromosomal division is extremely dense with functional genes: their sequences, genomic organization, and expression

We cloned and sequenced genomic DNA contigs spanning over 45 kb, surrounding the insertion site of the P-element that is responsible for the developmental defects in the ken and barbie (ken) mutant of Drosophila. This region harbors 10 functional transcription units, in addition to the already well-characterized TGFbeta-60A gene. These include the genes, undefined 1 (UD1), UD2, and UD3, each coding for proteins of unknown function, the ken gene encoding a new Krüppel-like putative transcription factor, the fly homologues of the mammalian mitochondrial trifunctional enzyme (thiolase), and the TAR DNA-binding protein-43 (TBPH), the first nonvertebrate member of the transmembrane 4 superfamily (TM4SF) gene, a new homeodomain gene, and a gene coding for a putative nuclear binding protein (PNBP) that is homologous to maleless, and a Copia-like element. UD3 exists in an intron of the maleless homologue, yet is expressed independent of it. The UD1 and TM4SF genes orient in a tail-to-tail manner with their 3' untranslated region sequences overlapping over 44 nucleotides. Thus the partial overlap and intraintronic organization permitted dense packing of the functional genes within a short segment of the genome.

Protein phosphatase 1-deficient mutant Drosophila is affected in habituation and associative learning

The learning and memory of Drosophila melanogaster strains carrying the Su-var(3)6(01) mutation, which is known to affect the structural gene of a protein phosphatase 1 isoenzyme, PP1(87B), were studied in various behavioral paradigms. Three lines of Drosophila comprising the Su-var(3)6(01) mutation in different genetic backgrounds were shown to have diminished protein phosphatase 1 activity and behavioral anomalies. Associative olfactory learning and visual conditioning were impaired. Olfactory acuity for the odorants used and response to electric shock were largely unchanged in the mutant lines. The motility and flight activity of the mutants were reduced. Habituation of the landing response, a nonassociative learning process, was more pronounced in heterozygotes of the mutants than in the wild-type control strains. Taken together with earlier data, the results indicate that protein phosphatase PP1(87B), while affecting several cellular processes, is also part of the biochemical machinery of various forms of neuromodulation in Drosophila.

On the pharmacological phenocopying of memory mutations in Drosophila: alkylxanthines accelerate memory decay

Theophylline and 3-isobutyl-1-methylxanthine, two cyclic nucleotide phosphodiesterase inhibitors, when fed to wild-type Drosophila adults, cause the rapid decay of learning index after training in a shock-odor learning paradigm. The drugs practically do not affect the olfactory acuity of flies, hence they influence the learning/memory process itself. The time courses of memory decay resemble those of the memory mutants rutabaga and amnesiac and, to a lesser extent, dunce2 and dunceM11. Theophylline further deteriorates the learning performance of dunceM11. Biochemical characterization of the inhibition of the two major phosphodiesterase isoenzymes in Drosophila by theophylline predicts only a slight inhibition of these enzymes in vivo, in accordance with the unchanged level of cAMP in wild-type fly heads during drug feeding. 8-Phenyltheophylline, an adenosine receptor antagonist in mammals, slightly retards memory decay in the wild-type. It is suggested that alkylxanthines induce memory decay in Drosophila by interfering with cAMP dynamics at more than one point of its metabolism.