Chronic exposure of Brown (Hydra oligactis) and green Hydra (Hydra viridissima) to environmentally relevant concentrations of pharmaceuticals

Low concentrations of pharmaceuticals in the environment (ng/L to μg/L) are an environmental concern. We used the invertebrates, Hydra oligactis and Hydra viridissima, as freshwater models for primary toxicity testing to study effects of chronic low concentrations of pharmaceuticals in the environment. H. oligactis were exposed to three concentrations (0.1, 1.0 and 10 μg/L) of either fluoxetine, carbamazepine, or triclosan; H. viridissima were exposed to three concentrations (0.1, 1.0 and 10 μg/L) of triclosan. Ecologically relevant endpoints including morphology, budding rate, feeding behaviour, and regenerative capacity were examined during the 14 days exposure period. The interstitial:epithelial stem cell ratios was also examined in H. oligactis. There were no significant effects on the morphology, budding rate and feeding behaviour of the H. oligactis across all concentrations of fluoxetine, carbamazepine, and triclosan. However, regenerative capacity significantly decreased in comparison to the controls when H. oligactis was exposed to 10 μg/L of triclosan and fluoxetine, although there was no significant difference when exposed to carbamazepine. Neither fluoxetine nor carbamazepine treatment altered stem cell ratios. Exposure to triclosan at any concentration did not impact H. viridissima morphology, budding rate, regeneration or feeding behaviour. These results show there are limited effects in Hydra after exposure to chronic, low concentrations of fluoxetine, carbamazepine, and triclosan, except for regeneration in H. oligactis. These endpoints can be used effectively (and cost effectively) to study the effects of environmentally relevant concentrations of pharmaceuticals in Hydra species.

Gastroprotective and anti-inflammatory activities integrated to chemical composition of Myracrodruon urundeuva Allemão - A conservationist proposal for the species

ETHNOPHARMACOLOGICAL RELEVANCE

Myracrodruon urundeuva Allemão (Aroeira-do-Sertão), Anacardiaceae, is one of the most used plants in folk medicine in Northeastern Brazil as an anti-inflammatory, healing and antiulcer. This species is threatened with extinction due to anthropogenic exploitation. The importance of this study is to demonstrate the feasibility of a conservationist model of replacement of the M. urundeuva adult tree (inner bark) for its under developing plants (shoots) in order to ensure the preservation of this species, but also to ensure sufficient raw material for pharmaceutical purposes.

AIM OF THE STUDY

To characterize chemically and assess the gastroprotective and anti-inflammatory activities of the fluid extracts from M. urundeuva innebark (adult plant) as well as stem and leaves of shoots (young plant).

MATERIALS AND METHODS

The fluid extracts were prepared by maceration-percolation with hydroalcoholic solution according to the methodology described in the Brazilian Pharmacopoeia. These extracts were cleaned-up through solid phase extraction (SPE) and chemically characterized by ultra-performance liquid chromatography coupled to mass spectrometry (UPLC-ESI-QTOF MS/MS). Gastroprotective and anti-inflammatory activities of the extracts (700 or 1000 mg/kg) were assessed on ethanol-induced gastric lesions and Croton oil-induced ear edema in rats, respectively. The extracts were evaluated for cytotoxicity in vitro.

RESULTS

The UPLC-ESI-QTOF-MS/MS analysis evidenced the presence of chalcones, flavonoids and tannins. Gastroprotective and anti-inflammatory activities achieved with fluid extracts from the stems and leaves was similar to inner bark. The fluid extracts were not toxic.

CONCLUSION

It is possible to replace the inner bark of the adult tree for the stems and leaves from the shoots as raw material to be used in the preparation of its the phytotherapeutics. Therefore, this finding may help in the implementation of public policies that ensure the conservation of the species along with its sustainable use for pharmaceutical purposes.

Provenance does matter: links between winter trophic segregation and the migratory origins of European robins

Amongst migratory species, it is common to find individuals from different populations or geographical origins sharing staging or wintering areas. Given their differing life histories, ecological theory would predict that the different groups of individuals should exhibit some level of niche segregation. This has rarely been investigated because of the difficulty in assigning migrating individuals to breeding areas. Here, we start by documenting a broad geographical gradient of hydrogen isotopes (δ ²H) in robin Erithacus rubecula feathers across Europe. We then use δ ²H, as well as wing-tip shape, as surrogates for broad migratory origin of birds wintering in Iberia, to investigate the ecological segregation of populations. Wintering robins of different sexes, ages and body sizes are known to segregate between habitats in Iberia. This has been attributed to the despotic exclusion of inferior competitors from the best patches by dominant individuals. We find no segregation between habitats in relation to δ ²H in feathers, or to wing-tip shape, which suggests that no major asymmetries in competitive ability exist between migrant robins of different origins. Trophic level (inferred from nitrogen isotopes in blood) correlated both with δ ²H in feathers and with wing-tip shape, showing that individuals from different geographic origins display a degree of ecological segregation in shared winter quarters. Isotopic mixing models indicate that wintering birds originating from more northerly populations consume more invertebrates. Our multi-scale study suggests that trophic-niche segregation may result from specializations (arising in the population-specific breeding areas) that are transported by the migrants into the shared wintering grounds.

Relaxant effects of an alkaloid-rich fraction from Aspidosperma ulei root bark on isolated rabbit corpus cavernosum

We described earlier that an alkaloid-rich fraction (F(3-5)) from Aspidosperma ulei (Markgr) induces penile erection-like behavioral responses in mice. This study verified a possible relaxant effect of this fraction on isolated rabbit corpus cavernosum (RbCC) strips precontracted by phenylephrine (1 microM) or K+ 60 mM. F(3-5) (1-300 microg ml(-1)) relaxed the RbCC strips in a concentration-dependent and reversible manner. The relaxant effect of F(3-5) (100 microg ml(-1)) on phenylephrine contraction was unaffected in the presence of atropine, N-omega-nitro-L-arginine methyl ester or 1H-[1,2,4]oxadiazole[4,3-a] quinoxalin-1-one and by preincubation with tetrodotoxin, glibenclamide, apamine and charybdotoxin suggesting that mechanisms other than cholinergic, nitrergic, sGC activation or potassium channel opening are probably involved. However, the phasic component of the contraction induced by K+ 60 mM as well as the maximal contraction elicited by increasing external Ca2+ concentrations in depolarized corpora cavernosa was inhibited by F(3-5). We conclude that F(3-5) relaxes the RbCC smooth muscle, at least in part, through a blockade of calcium influx or its function.

Acute effects of guarana (Paullinia cupana Mart.) on mouse behaviour in forced swimming and open field tests

Guarana, a herbal extract from the seeds of Paullinia cupana Mart. has been evaluated in comparison with caffeine on mouse behaviour in forced swimming and open field tests. Guarana (25 and 50 mg/kg, p.o.) and caffeine (10 and 20 mg/kg, p.o.) each significantly reduced the duration of immobility in the forced swimming test suggesting an antidepressant-like effect in mice. At these doses, neither substance affected ambulation in the open field test. However, a high dose of guarana (100 mg/kg) and caffeine (30 mg/kg) significantly enhanced the locomotor activity in the open field test. Caffeine, but not guarana, could effectively block an adenosine agonist, cyclopentyl adenosine (CPA)-induced increase in swimming immobility suggesting that mechanism(s) other than the adenosinergic mechanism are involved in the antidepressant-like activity of guarana.

Attenuation of ischemia/reperfusion-induced intestinal injury by oleo-resin from Copaifera langsdorffii in rats

Copaifera langsdorffii oleo-resin (CLOR) is a reputed herbal medicine used to combat gastrointestinal functional disorders. Our previous studies show that CLOR prevents gastric ulceration and promotes wound healing. This study examined the effects of CLOR on intestinal damage associated with mesenteric ischemia/reperfusion in rat. Wistar albino rats were divided into four groups of six in each. Group 1: Sham operated, Group 2: Vehicle + 45 min of ischemia followed by 60 min reperfusion (I/R), Groups 3 and 4: I/R + CLOR (200 and 400 mg /kg, p.o., respectively). All treatments were given 24 h, 12 h and 2 h before I/R. Animals were sacrificed at the end of reperfusion period and ileal tissue samples were obtained for biochemical analysis. Myeloperoxidase (MPO), an index of polymorphonuclear leukocytes; malondialdehyde (MDA), an end product of lipoperoxidation; catalase (CAT), an antioxidant enzyme; reduced glutathione (GSH), a key antioxidant; and nitrite, a marker of nitric oxide (NO) production were determined in ileum homogenates. The results show that I/R produces a significant increase in MDA content, MPO, and CAT activities with a significant decrease in GSH and an elevation in nitrite production, as compared to sham control. CLOR treatment caused significant attenuations in I/R-associated increases of MPO, MDA and CAT activities and on nitrite level. Besides, CLOR could effectively prevent the I/R-associated depletion of GSH. The data indicate that the oleo-resin has a protective action against I/R-induced intestinal tissue damage, which appeared to be, at least in part, due to an antioxidant and anti-lipid peroxidation mechanism.

1,8-cineole (eucalyptol), a monoterpene oxide attenuates the colonic damage in rats on acute TNBS-colitis

The monoterpene oxide, 1,8-cineole (cineole, eucalyptol) was examined for its possible influence on the acute phase of trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats. The test compound, 1,8-cineole (200 and 400 mg/kg) or vehicle (1 ml, 2% Tween 80) was instilled rectally, 24, and 2 h before (pre-treatment) or 2 and 24 h after (post-treatment) the induction of colitis by intracolonic administration of TNBS (0.25 ml of 25 mg of TNBS in 50% ethanol). Rats were killed 48 h after colitis induction and colonic segments were analysed for gross damage scores, changes in wet weights, myeloperoxidase activity, an indicator of neutrophilic infiltration and glutathione level, a major cellular antioxidant. TNBS induced an extensive inflammation and ulceration in the colon. Colonic damage was associated with an increase in myeloperoxidase activity and by a decrease in glutathione. When compared to vehicle-treated TNBS controls, a marked reduction in gross damage scores and wet weights (mg/cm) of colonic segments were evident in animals pre-treated but not post-treated with 1,8-cineole. Cineole also significantly reduced the myeloperoxidase activity, and caused repletion of glutathione. These results confirm the anti-inflammatory action of 1,8-cineole and suggest its potential value as a dietary flavoring agent in the prevention of gastrointestinal inflammation and ulceration.

Ternatin, an anti-inflammatory flavonoid, inhibits thioglycolate-elicited rat peritoneal neutrophil accumulation and LPS-activated nitric oxide production in murine macrophages

Ternatin, an anti-inflammatory flavonoid from Egletes viscosa Less., was examined for its possible influence on thioglycolate-elicited neutrophil influx into the rat peritoneal cavity in vivo and nitric oxide production in lipopolysaccharide (LPS)-activated mouse peritoneal macrophages ex vivo. The neutrophil influx induced by thioglycolate was found to be significantly lower in ternatin (25 and 50 mg/kg, s. c.) pre-treated rats with a similar magnitude of inhibition produced by dexamethasone (1 mg/kg, s. c.), a known anti-inflammatory agent. Also, peritoneal macrophages from ternatin (25 mg/kg)-treated mice that were exposed to LPS demonstrated significantly less production of nitric oxide (NO). These results suggest that ternatin exerts its anti-inflammatory action, at least in part, through inhibition of neutrophil migration and modulation of macrophage function.

Guarana (Paullinia cupana Mart.) offers protection against gastric lesions induced by ethanol and indomethacin in rats

The effects of guarana (Paullinia cupana) extract were analyzed in rats on acute gastric lesions induced by ethanol and indomethacin and were compared to those produced by caffeine, a methylxanthine. Guarana (50 and 100 mg/kg p.o.) pretreated animals showed a significant reduction in the severity of gastric lesions induced by absolute ethanol in a manner similar to caffeine (20 and 30 mg/kg p.o.). Against indomethacin-induced gastric ulceration, guarana at a higher dose offered significant protection but caffeine was ineffective at the doses tested. In 4 h pylorus-ligated rats, both guarana and caffeine caused significant diminution in the gastric secretory volume as well as the total acidity. Gastrointestinal transit in mice was not significantly affected by either of these agents. These findings indicate that guarana has a gastroprotective property that needs further elucidation as regards to its mechanism.

Cloning, genomic organization and expression pattern of a novel Drosophila gene, the disco-interacting protein 2 (dip2), and its murine homolog

We report the cloning and initial characterization of a novel gene encoding the Disco interacting protein 2 (Dip2). dip2 DNA complementary to RNA (cDNA) showed a high degree of sequence similarity to cDNAs of unknown function previously identified in humans and Caenorhabditis elegans. We have cloned the mouse homolog of the dip2 cDNA and characterized the expression of this gene by Northern blotting analysis and in situ hybridization to whole mount embryos. Our observations demonstrate that there is a remarkable degree of sequence conservation at the dip2 locus that is reflected in the nervous system-specific expression of both the Drosophila and mouse homologs.

Investigations on the antinociceptive activity of crude extracts from Croton cajucara leaves in mice

The crude leaf extracts of Croton cajucara Benth. were studied for their antinociceptive property in chemical and thermal models of nociception in mice. All the tested extracts (hexanic, chloroformic and methanolic), at oral doses of 100 and 200 mg/kg demonstrated significant inhibition of acetic acid-induced writhing and the second phase response of formalin, but did not manifest a significant effect in hot-plate test.

Drosophila Amphiphysin is a post-synaptic protein required for normal locomotion but not endocytosis

Clathrin-mediated endocytosis is required to recycle synaptic vesicles for fast and efficient neurotransmission. Amphiphysins are thought to be multiprotein adaptors that may contribute to this process by bringing together many of the proteins required for endocytosis. Their in vivo function, however, has yet to be determined. Here, we show that the Drosophila genome encodes a single amphiphysin gene that is broadly expressed during development. We also show that, unlike its vertebrate counterparts, Drosophila Amphiphysin is enriched postsynaptically at the larval neuromuscular junction. To determine the role of Drosophila Amphiphysin, we also generated null mutants which are viable but give rise to larvae and adults with pronounced locomotory defects. Surprisingly, the locomotory defects cannot be accounted for by alterations in the morphology or physiology of the neuromuscular junction. Moreover, using stimulus protocols designed to test endocytosis under moderate and extreme vesicle cycling, we could not detect any defect in the neuromuscular junction of the amphiphysin mutant. Taken together, our findings suggest that Amphiphysin is not required for viability, nor is it absolutely required for clathrin-mediated endocytosis. However, Drosophila Amphiphysin function is required in both larvae and adults for normal locomotion.

Behavioral characterization and genetic analysis of the Drosophila melanogaster larval response to light as revealed by a novel individual assay

A new assay was designed, named checker, that measures the individual response to light in the fruitfly Drosophila melanogaster larva. In this assay the Drosophila larva apparently modulates its pattern of locomotion when faced with a choice between a dark and lit environment by orienting its movement towards the dark environment. We show that, in this assay, a response to light can be measured as an increase in residence time in the dark versus the lit quadrant. Mutations that disrupt phototransduction in the adult Drosophila abolish the larval response to light, demonstrating that this larval visual function is similar to that of the adult fly. Similarly, no response to light was detected in strains where the larval visual system (photoreceptors and target area) was disrupted by a mutation in the homeobox containing gene sine oculis (so) gene. Ablation of photoreceptors by the targeted expression of the cell death gene hid under the control of the photoreceptor-specific transcription factor glass (gl) abolishes this response entirely. Finally, we demonstrate that this response to light can be mediated by rhodopsins other than the blue absorbing Rh1.

The tamas gene, identified as a mutation that disrupts larval behavior in Drosophila melanogaster, codes for the mitochondrial DNA polymerase catalytic subunit (DNApol-gamma125)

From a screen of pupal lethal lines of Drosophila melanogaster we identified a mutant strain that displayed a reproducible reduction in the larval response to light. Moreover, this mutant strain showed defects in the development of the adult visual system and failure to undergo behavioral changes characteristic of the wandering stage. The foraging third instar larvae remained in the food substrate for a prolonged period and died at or just before pupariation. Using a new assay for individual larval photobehavior we determined that the lack of response to light in these mutants was due to a primary deficit in locomotion. The mutation responsible for these phenotypes was mapped to the lethal complementation group l(2)34Dc, which we renamed tamas (translated from Sanskrit as "dark inertia"). Sequencing of mutant alleles demonstrated that tamas codes for the mitochondrial DNA polymerase catalytic subunit (DNApol-gamma125).

Antioestrogenic effect of trans-dehydrocrotonin, a nor-clerodane diterpene from Croton cajucara Benth. in rats

This study examined trans-dehydrocrotonin (t-DCTN), a nor-clerodane diterpene isolated from the Brazilian medicinal plant Croton cajucara Benth., for a possible antioestrogenic activity using immature rats as a model system for bioassay of oestrogen, and for an antiimplantation effect in regularly cycling rats of proven fertility. In the antioestrogen test, t-DCTN (25 and 50 mg/kg) effectively prevented oestrogen-induced increases of uterine wet weights. In addition, the vaginal openings provoked by oestrogen were completely prevented by t-DCTN. However, blastocyst-implantation was only insignificantly affected in t-DCTN pretreated animals. These results suggest that t-DCTN may be an antioestrogen and warrants further studies with regard to its mechanism of action.

Autoregulation of the Drosophila disconnected gene in the developing visual system

The Drosophila disconnected (disco) gene is required for the formation of appropriate connections between the larval optic nerve and its target cells in the brain. The disco gene encodes a nuclear protein with two zinc fingers, which suggests that the gene product is a transcription factor. Here, we present data supporting this notion. We find that disco expression in the optic lobe primordium, a group of cells contacted by the developing optic nerve, depends on an autoregulatory feedback loop. We show that wild-type disco function is required for maintenance of disco mRNA and protein expression in the developing optic lobe. In addition, we demonstrate that ubiquitous Disco activity supplied by a heat-inducible gene construct activates expression from the endogenous disco gene specifically in the optic lobe primordium. Consistent with a role of Disco as a transcriptional regulatory protein, we show that portions of the Disco protein are capable of activating the transcription of reporter constructs in a heterologous system. Moreover, we find that the zinc finger portion of Disco binds in vitro to sequences located near the disco transcription unit, suggesting that Disco autoregulates its transcription in the optic lobe primordium by direct binding to a regulatory element in its own promoter.

Genetic dissection of behavior: modulation of locomotion by light in the Drosophila melanogaster larva requires genetically distinct visual system functions

The Drosophila larva modulates its pattern of locomotion when exposed to light. Modulation of locomotion can be measured as a reduction in the distance traveled and by a sharp change of direction when the light is turned on. When the light is turned off this change of direction, albeit significantly smaller than when the light is turned on, is still significantly larger than in the absence of light transition. Mutations that disrupt adult phototransduction disrupt a subset of these responses. In larvae carrying these mutations the magnitude of change of direction when the light is turned on is reduced to levels indistinguishable from that recorded when the light is turned off, but it is still significantly higher than in the absence of any light transition. Similar results were obtained when these responses were measured in strains where the larval photoreceptor neurons were ablated by mutations in the glass (gl) gene or by the targeted expression of the cell death gene head involution defective (hid). A mutation in the homeobox gene sine oculis (so) that ablates the larval visual system, or the targeted expression of the reaper (rpr) cell death gene, abolishes all responses to light detected as a change of direction. We propose the existence of an extraocular light perception that does not use the same phototransduction cascade as the adult photoreceptors. Our results indicate that this novel visual function depends on the blue-absorbing rhodopsin Rh1 and is specified by the so gene.

Effects of acute and repeated dose administration of caffeine and pentoxifylline on diazepam-induced mouse behavior in the hole-board test

RATIONALE

The behavioral effects of methyl xanthines and their interactions with benzodiazepines have not been clearly established in animal models of anxiety.

OBJECTIVE

The present study extended the previous studies to determine the effects of acute and repeated administration of caffeine, a non-specific phosphodiesterase (PDE) inhibitor and pentoxyfylline, a specific type-4 phosphodiesterase (PDE4) inhibitor on (1) baseline anxiety-like behavior and (2) the response to an acute challenge with diazepam on anxiety-like behavior in the hole-board test.

METHODS

Mice were observed for the number of head-dips they made into the holes of the hole-board apparatus during a 5-min period, starting 30 min after acute (20 mg/kg) and repeated oral dose (20 mg/kg, twice a day for 4 days) administration of caffeine and pentoxifylline. In separate experiments, the response to an acute challenge with graded doses of diazepam (0.375 3 mg/kg, SC) was observed in naive mice or mice on acute and repeated dose regimen with methyl xanthines.

RESULTS

Mice on acute but not after repeated dose regimen demonstrated a significantly increased number of hole-dips, indicating an anxiolytic-like effect of methylxanthines. Diazepam at the lower doses (0.375 and 0.75 mg/kg) but not at the highest doses (1.5 and 3 mg/kg) examined produced a significant anxiolytic-like effect. After an acute dose exposure of mice to caffeine and pentoxifylline, a rightward shift in the dose-response curve of diazepam was observed and particularly at 1.5 mg/kg dose, the net effect of diazepam was significantly enhanced which was, however, impaired upon repeated administration, more so with caffeine than with pentoxifylline.

CONCLUSIONS

It is concluded that the xanthine drugs exert anxiolytic-like activity similar to diazepam in the hole-board test. In addition, they seem to modulate the anxiolytic effects of diazepam after both acute and repeated administration, probably as a result of an endogenous adenosinergic mechanism which may have therapeutic significance.

Mutations in the gene stand still disrupt germ cell differentiation in Drosophila ovaries

During oogenesis in Drosophila, germ cells appear in sequential clusters of 16 interconnected cells. The events surrounding the differentiation of these cells are not fully understood. Here we present genetic and morphological analysis of mutations in the gene stand still (stil). Through complementation analyses we have refined the location of this gene to cyological region 49B-C. Our analyses of ovaries from ethylmethane sulfonate (EMS)-induced mutant alleles of this gene suggest that mutations in the stil gene produce a wide range of phenotypic abnormalities, from the absence of germ cells in the most severe alleles, to egg chambers with cytoskeletal defects in the less severe alleles. Our results suggest a role for this gene in specifying or maintaining a cytoskeletal component, with consequences during oogenesis and possibly during germ line sex determination.

Characterization and genetic analysis of Drosophila melanogaster photobehavior during larval development

In Drosophila melanogaster, during the mid third instar of development larvae cease foraging and commence a period of increased locomotor activity referred to as wandering behavior. In this study, we quantified the wild type larval response to light during the foraging (first, second, and early third instars) and wandering (late third instar) stages of development. Foraging larvae in the first, second and early third instars exhibited a robust and marked aversion to light (negative phototaxis). From the mid larval third instar larvae showed a decrease in photonegative behavior, until just before pupation when the response of wandering larvae to light became random. The photobehavior of several strains known to affect the adult visual system were also studied. All but four exhibited normal phototaxis in the foraging and wandering stages. gl mutant larvae failed to respond to light during the foraging stage likely due to lack of larval photoreceptors. Larvae carrying three different mutations in the rhodopsin RH1 gene continued to express negative phototaxis throughout both the foraging and wandering stages. These results suggest that the transition from negative phototaxis toward photoneutral behavior characteristic of the wandering third instar larva requires vision.

Establishment of neuronal connectivity during development of the Drosophila larval visual system

We used confocal microscopy in conjunction with specific antibodies and enhancer trap strains to investigate the development of specific neuronal connections in a simple model system, the larval visual system of Drosophila. We find that the establishment of axonal projections from the larval photoreceptor neurons to their central nervous system targets involves a series of discrete steps. During embryogenesis, the larval optic nerve contacts several different cell types, including optic lobe pioneer (OLP) neurons and a number of glial cells. We demonstrate that OLP neurons are present and project normally in glass (gl) mutant embryos in which the larval optic nerve fails to develop, suggesting that they do not depend on interactions with the larval optic nerve for differentiation and proper axonal projection. The OLPs fail to differentiate properly is disconnected (disco) mutant embryos, where appropriate connections between the larval optic nerve and its targets in the brain are not formed. The disco gene is expressed in the OLPs and may therefore act autonomously to direct the differentiation of these cells. Taken together, our results suggest that the OLPs act as an intermediate target required for the establishment of normal optic nerve projection and connectivity.

The larval optic nerve is required for the development of an identified serotonergic arborization in Drosophila melanogaster

The larval visual system in the fruitfly Drosophila melanogaster consists of two bilateral clusters of 12 photoreceptor cells. These neurons send their axons in a fascicle, the Bolwig's nerve, toward the target area in the ventral lateral region of the brain hemispheres. We describe the development of a serotonergic arborization originating in the central brain found in the larval optic center in association with the larval optic nerve. This arborization is formed by processes from larval neurons born during embryogenesis. However, these neuronal processes do not reach their final destination, the larval optic center, until late in larval development. Using mutations that disrupt the connectivity and/or development of the larval photoreceptor cells, as well as mosaic analysis, we demonstrate that the innervation of the larval optic center by this serotonergic arborization depends upon contact with the larval optic nerve.

Survival of photoreceptor neurons in the compound eye of Drosophila depends on connections with the optic ganglia

The importance of retinal innervation for the normal development of the optic ganglia in Drosophila is well documented. However, little is known about retrograde effects of the optic lobe on the adult photoreceptor cells (R-cells). We addressed this question by examining the survival of R-cells in mutant flies where R-cells do not connect to the brain. Although imaginal R-cells develop normally in the absence of connections to the optic lobes, we find that their continued survival requires these connections. Genetic mosaic studies with the disconnected (disco) mutation demonstrate that survival of R-cells does not depend on the genotype of the eye, but is correlated with the presence of connections to the optic ganglia. These results suggest the existence of retrograde interactions in the Drosophila visual system reminiscent of trophic interactions found in vertebrates.

Isolation and characterization of the disconnected gene of Drosophila melanogaster

Mutations in the disco (disconnected) gene prevent the establishment of stable connections between the larval optic nerves, the Bolwig's nerves, and their target cells in the brain during embryonic development. The failure of this initial connection is associated with aberrant development of the optic lobes which are largely degenerate in the mutant adult fly. In order to understand the role of disco in establishing this connection, we isolated and characterized the disco gene. A 22 kb DNA fragment can completely rescue the mutant phenotype. A single transcript, 2.9 kb in length, is found in this region and is expressed throughout development of the fly. We determined the nucleotide sequence of the disco gene to be unique when compared with sequences in a number of databases. The predicted amino acid sequence contains a region with similarity to the consensus established for the zinc finger motif. Mobilization of a P-element inserted near the gene resulted in the deletion of the 5' end of the gene and produced flies indistinguishable from those carrying the disco allele.

The elav gene product of Drosophila, required in neurons, has three RNP consensus motifs

A sequence of developmental events transforms neurons from their immature state to their mature, terminally differentiated state. The elav locus is one of the first examples of a gene that is expressed in neurons early during this developmental sequence. This gene has been shown to be required for the proper development of young neurons and for the maintenance of mature neurons. DNA sequence data presented in this report suggest that the elav gene product is an RNA binding protein, based on the presence of RNP (ribonucleoprotein) consensus sequences. This leads to the proposal that this protein is involved in the RNA metabolism of neurons.

Molecular analysis of the locus elav in Drosophila melanogaster: a gene whose embryonic expression is neural specific

The embryonic lethal abnormal visual system (elav) locus in Drosophila melanogaster, a vital gene mapping within the 1B5-1B9 region of the X-chromosome has been cloned and analysed. Previous developmental analyses have shown that in addition to the embryonic requirement there is a post-embryonic requirement for elav function in the cells of the visual system. A DNA segment containing elav+ function was defined through germ line transformation experiments. This region encodes three embryonic poly(A)+ RNAs and two adult transcripts which are preferentially expressed in the head. In situ hybridization experiments clearly demonstrate that the embryonic expression of elav is restricted to the nervous system.

Mutant alleles at the locus elav in Drosophila melanogaster lead to nervous system defects. A developmental-genetic analysis

We report a developmental and genetic analysis of the X-linked vital locus l(1)EC7 in Drosophila melanogaster. The locus maps in the salivary band region 1B4-5 to 1B8-9, a part of the X chromosome previously shown to be essential for normal neural development. Certain mutant alleles at the locus can cause embryonic lethality, indicating that the function provided by the gene is essential during embryogenesis. A developmental analysis of gynandromorphic genetic mosaics shows that: (1) the gene function is autonomously essential in the eye; (2) the gene function is essential for normal development of the optic lobes; and (3) the gene function is not necessary in most major imaginal-disc cell derivatives with the exception of the eye disc. Conclusions from the developmental analysis of a temperature sensitive allele are consistent with those from the mosaic analysis. The embryonic lethality caused by the mutant alleles and abnormalities observed in the genetic mosaics have led us to rename the locus l(1)EC7 to elav (embryonic lethal, abnormal visual system).

Differential staining of the X-chromosome during meiosis of orthoptera by a silver impregnation procedure

Differential staining of the X chromosome of Orthoptera, which normally cannot be distinguished from the autosomes during the more condensed stages of meiosis, has been achieved by a silver impregnation procedure involving a pretreatment with 2 x SSC at 60 degrees C. The results suggest that the saline citrate solution preferentially extracts proteins from the X chromosome. This method may be useful for distinguishing chromosome regions composed of facultative heterochromatin in Orthoptera.

Human schistosomiasis: Schistosoma mansoni antigen detection in renal glomeruli

Twelve kidney, five biopsy and seven necropsy specimens, all from schistosomiasis mansoni patients were studied by light and immunoflurescent microscopy in an attempt to detect antigen in the glomerular walls. Deposits of IgM, IgG,I gA, IgE, complement C3 and fibrinogen were observered in most cases. Antigen was successfully detected in two cases(one biopsy and one necropsy specimen), both exhibiting proliferative glomerulonephritis. The only clinical manifestation was a slight proteinuria. IgG antibodies eluted from the sutopsy kidney homogenates showed specific binding mostly to Schistosoma mansoni gut, thus spggesting that the fixed antibodies (eluates) are, at least partially, consituted by antibodies similar to the anti-circulating antigen. These data reinfroce the hypothesis that renal injury in schistosomiasis is mediated through an immune complex disease.