Processing and characterization of antimicrobial bioplastic films based on green microalgae Scenedesmus obliquus extract-loaded polyurethane.

The green microalga Scenedesmus obliquus, isolated from the Egyptian environment, was used for the synthesis of bio-based plastic materials. Polyurethane (PU) was blended with different proportions (0%, 10%, 20%, and 40%) of chloroform extract to form bioplastic films. The bioplastic films were characterized using water vapor transmission rate measurements and scanning electron microscopy (SEM). The WVTR of pure PU was 193.37 g/m2. day, while the values of algae/PU films were 129.74, 122.56, and 99.75 g/m2.day. S. obliquus reported having Palmitic, which possesses antimicrobial activity and acts as an effective antimicrobial agent in the synthesized bioplastic films. Antimicrobial activity of the algal extract and the synthesized bioplastic films were tested against two Gram-positive bacteria; Staphylococcus aureus, Enterococcus faecalis, two Gram-negative bacteria; Escherichia coli, Pseudomonas aeruginosa, and Candida albicans as a model for fungi. The results indicated that S. obliquus extract exhibited a clear antimicrobial activity against all tested microbes. The antimicrobial rate of bioplastic films containing 40% of the extract reached 100% after 2 h of contact with E. coli and E. faecalis. In conclusion, this study offers a promising future for the use of biodegradable antimicrobial bioplastic films as an affordable and environmentally friendly alternative to plastics in many applications.

Insights into the mechanism of histamine synthesis and recycling disruption induced by exposure to CdO NPs in the fruit fly (Drosophila melanogaster).

Exposure to a sublethal concentration of CdO nanoparticles impairs the vision of the fruit fly (Drosophila melanogaster) by disrupting histamine (HA) synthesis and recycling mechanisms. To gain more insights, we measured HA titer using HPLC in CdO NP-treated vs. non-treated adults in the current study and found that CdO NPs caused an increase in the level of HA in the head and the decapitated body. We asked whether HA accumulation (increase) is a response of photoreceptors or CNS histaminergic neurons, and whether there is any difference in the expression levels of HA recycling and transport encoding genes (Lovit, CarT, Ebony, Tan, BalaT) between the adult fly head and decapitated body that could explain this HA accumulation. We used GAL4/UAS system tool with three GAL4 drivers: ubiquitous tubP-GAL4, nervous system driver (elav Gal4), and compound eye drivers (sev Gal4 and GMR Gal4) to silence HA synthesis in site specific manner followed by detecting the expression level of genes involved in HA recycling and transport in both the heads and the decapitated bodies of CdO treated and non-treated flies. We found an increase in Lovit expression in the heads of treated adults, which is responsible for HA loading into synaptic vesicles and release from photoreceptors, as well as a decrease in catalytic enzymes involved in HA recycling, which leads to HA accumulation without increasing the real signal. To conclude, both photoreceptors and CNS histaminergic neurons are responsible for the increase in HA in CdO NP-treated flies, but through different mechanisms. Our results provide more insights on the underlying molecular mechanism of vision impairment because of nano-sized cadmium particles exposure.

Exposure to polystyrene microplastic beads causes sex-specific toxic effects in the model insect Drosophila melanogaster.

The toxicity of MPs on aquatic creatures has been extensively studied, but little attention was paid to terrestrial organisms. To fill this gab, we conducted a series of experiments using Drosophila as a model organism to understand whether exposure to different concentrations (0.005, 0.05, 0.5 µg/ml) of polystyrene microplastics (PS-MPs) beads (2 µm in size) can impact flies feeding activity, digestion and excretion. The ability of flies to distinguish between normal and PS-MPs treated food media was tested first, and then we evaluated the effects of a 7-day short-term exposure to PS-MPs on food intake, mortality, starvation resistance, fecal pellet count, and the cellular structure of mid gut cells. The results revealed that flies can really differentiate and ignore MPs-treated food. We discovered sex-specific effects, with male flies being more sensitive to PS-MPs, with all males dying after 14 days when exposed to 0.5 µg/ml of PS-MPs, whereas female flies survived more. All male flies exposed to PS-MPs died after 24 h of starvation. Midgut cells showed concentration-dependent necrosis and apoptosis in response to PS-MPs. Our findings provide new insights into MPs toxicity on terrestrial organisms and giving a warning that management measures against MPs emission must be taken.

Exposure to a sublethal concentration of CdO nanoparticles impairs the vision of the fruit fly (Drosophila melanogaster) by disrupting histamine synthesis and recycling mechanisms.

While there is substantial literature on potential risks associated with exposure to emerging nanomaterials, less is known about the potential effects of hazardous metallic nanoparticles on vision, as well as the mechanisms that underpin them. The fruit fly (Drosophila melanogaster) was used as an in vivo model organism to investigate the effects of exposure to a sublethal concentration (0.03 mg CdO NPs/mL, which was 20% of the LC50) on fly vision and compound eye ultrastructure. First, we observed a reduction in phototaxis response in treated flies but no change in locomotor activity. Because histamine (HA) has been linked to arthropod vision, we investigated HA synthesis, uptake, and recycling as a possible underlying mechanism for the observed adverse effect of CdO NPs on fly vision. This was accomplished by measuring the expression of the histamine decarboxylase (hdc) gene, which encodes the enzyme that converts the amino acid histidine to histamine (HA), as well as the expression of some genes involved in HA-recycling pathways (tan, ebony, Balat, CarT, and Lovit). The results showed that CdO NPs changed the expression levels of hdc, Lovit, tan, and eboney, indicating that HA synthesis, transport, and recycling were disrupted. Furthermore, less histamine immunolabeling was found in the head tissues of CdO NP-treated flies, particularly in the optic lobes. We also observed and quantified CdO NP bioaccumulation in compound eye tissues, which resulted in a number of cytological changes. Phenotypic effects (undersized eyes) have also been observed in the compound eyes of F1 flies. Considering the significance of vision in an organism's survival, the findings of this study are extremely crucial, as long-term exposure to CdO NPs may result in blindness.

Octopamine signaling via OctαR is essential for a well-orchestrated climbing performance of adult Drosophila melanogaster.

The biogenic amine octopamine (OA) orchestrates many behavioural processes in insects. OA mediates its function by binding to OA receptors belonging to the G protein-coupled receptors superfamily. Despite the potential relevance of OA, our knowledge about the role of each octopaminergic receptor and how signalling through these receptors controls locomotion still limited. In this study, RNA interference (RNAi) was used to knockdown each OA receptor type in almost all Drosophila melanogaster tissues using a tubP-GAL4 driver to investigate the loss of which receptor affects the climbing ability of adult flies. The results demonstrated that although all octopaminergic receptors are involved in normal negative geotaxis but OctαR-deficient flies had impaired climbing ability more than those deficient in other OA receptors. Mutation in OA receptors coding genes develop weak climbing behaviour. Directing knockdown of octαR either in muscular system or nervous system or when more specifically restricted to motor and gravity sensing neurons result in similar impaired climbing phenotype, indicating that within Drosophila legs, OA through OctαR orchestrated the nervous system control and muscular tissue responses. OctαR-deficient adult males showed morphometric changes in the length and width of leg parts. Leg parts morphometric changes were also observed in Drosophila mutant in OctαR. Transmission electron microscopy revealed that the leg muscles OctαR-deficient flies have severe ultrastructural changes compared to those of control flies indicating the role played by OctαR signalling in normal muscular system development. The severe impairment in the climbing performance of OctαR-deficient flies correlates well with the completely distorted leg muscle ultrastructure in these flies. Taken together, we could conclude that OA via OctαR plays an important multifactorial role in controlling locomotor activity of Drosophila.

Alterations in biogenic amines levels associated with age-related muscular tissue impairment in Drosophila melanogaster.

While holding on youth may be a universal wish, aging is a natural process associated with physical and physiological impairment in living organisms. Drosophila provides useful insights into aging-related events. Hence, this study was conducted to investigate the age-related changes in muscle function and architecture in relation to the biogenic amine titers. To achieve this aim, visceral and skeletal muscles performance was tested in newly-eclosed, sexually mature and old adult flies using climbing and gut motility assays. In addition, age-related ultrastructural alterations of muscular tissue were observed using transmission electron microscopy (TEM). The titer of selected biogenic amines was measured using high-performance liquid chromatography (HPLC). The results demonstrated that old flies were dramatically slower in upward movement than either newly-eclosed or sexually mature flies. Similarly, gut contraction rate was significantly lower in old flies than the sexually mature, although it was markedly higher than that in the newly-eclosed flies. In TEM examination, there were several ultrastructural changes in the midgut epithelium, legs and thorax muscles of old flies. Regarding biogenic amine titers, the old flies had significantly lower concentrations of octopamine, dopamine and serotonin than the sexually mature. We concluded that aging has adverse effects on muscular system function and ultrastructure, synchronized with biogenic amine titers changes. Our results highlighted the need for more researches on therapeutics that may balance the levels of age-related alterations in biogenic amines.

Cellular properties of human gingival fibroblasts on novel and conventional implant-abutment materials.

OBJECTIVES: To characterize human-gingival-fibroblast-(HGFs) viability, proliferation and adhesion on polymer-infiltrated-ceramic-network-(PICN), polyetheretherketone-(PEEK), hydroxyapatite-reinforced-polyetheretherketone-(HA-PEEK), polyetherketoneketone-(PEKK), as well as conventional titanium-(Ti) and zirconia ceramic-(Zr) implant materials in-vitro. METHODS: Six materials (n = 40/group, 240 specimens) were standardized for surface roughness, assessed employing water contact angle measurements (WCA) and loaded with HGFs. HGF viability and proliferation were assessed at 24 and 72 h. Cell adhesion strength was evaluated after 24 h exposure to lateral shear forces using a shaking-device at 320 and 560-rpm.and qualitatively tested by scanning-electron-microscopy-(SEM) at 3, 24 and 72 h. RESULTS: PICN demonstrated the lowest mean WCA (48.2 ± 6.3º), followed by Zr (73.8 ± 5.1º), while HA-PEEK showed the highest WCA (87.2 ± 1.5º; p ≤ 0.05). After 24 h, Zr showed the highest mean HGFs-viability rate (88 ± 14%), while PEKK showed the lowest one (78 ± 7%). At 72 h, Zr continued to show the highest HGF-viability (80 ± 6%) compared to PEKK (67.5 ± 6%) and PEEK (67%±5). SEM did not reveal differences between different materials with respect to cell attachment at 3, 24 or 72 h. At 320 rpm shaking, HGFs showed to be best attached to PICN (mean%-of-detached-cells ± SD; 26 ± 11%) and worst to PEEK (54 ± 18%). At 560 rpm shaking, Zr showed the least detached cells (32 ± 4%), while HA-PEEK revealed the highest number of detached cells (58 ± 3%; ANOVA/Tukey-post-hoc-test, differences not statistically significant). SIGNIFICANCE: Dental implant abutment materials and their wettability strongly affect HGF proliferation and adhesion properties. Although, PICN showed the best wettability properties, Zr exhibited the strongest adhesion strength at high shaking. Within the current study's limitations, Zr remains the most biocompatible abutment material.

Reduced fitness of the mosquito Culex pipiens (Diptera: Culicidae) after feeding on a blood meal with hepatitis C virus.

Hepatitis C virus (HCV) is a blood-borne virus. Given that mosquitoes can take blood meals from HCV patients, we aimed to test whether HCV in the blood meal can induce alterations in the biology of Culex pipiens. To address this aim, Cx. pipiens females were fed HCV-negative blood from healthy individuals or HCV-positive fresh blood samples harvested from viremic HCV patients. Replication of HCV in mosquitoes was confirmed by negative strand-specific RT-PCR and sequencing of RNA extracted from the mosquito bodies 7 days post-feeding. In addition, several parameters that determine the fitness of the mosquitoes were measured. Virus acquisition was associated with alterations in the architecture of the gut microvilli and the immune response, indicated by an increase in phenol oxidase activity. Interestingly, the mosquitoes that were fed the HCV-positive blood meal showed shorter median longevity (8 days) and laid fewer eggs than the control mosquitoes. Furthermore, the offspring of females fed the HCV-positive blood meal demonstrated a lower emergence rate than the controls. In sum, the results indicate that feeding on HCV by Cx. pipiens decreases fitness, which may, in turn, affect its potential as a vector.

Dopamine Modulates Drosophila Gut Physiology, Providing New Insights for Future Gastrointestinal Pharmacotherapy.

Dopamine has a variety of physiological roles in the gastrointestinal tract (GI) through binding to Drosophila dopamine D1-like receptors (DARs) and/or adrenergic receptors and has been confirmed as one of the enteric neurotransmitters. To gain new insights into what could be a potential future promise for GI pharmacology, we used Drosophila as a model organism to investigate the effects of dopamine on intestinal physiology and gut motility. GAL4/UAS system was utilized to knock down specific dopamine receptors using specialized GAL4 driver lines targeting neurons or enterocytes cells to identify which dopamine receptor controls stomach contractions. DARs (Dop1R1 and Dop1R2) were shown by immunohistochemistry to be strongly expressed in all smooth muscles in both larval and adult flies, which could explain the inhibitory effect of dopamine on GI motility. Adult males' gut peristalsis was significantly inhibited by knocking down dopamine receptors Dop1R1, Dop1R2, and Dop2R, but female flies' gut peristalsis was significantly repressed by knocking down only Dop1R1 and Dop1R2. Our findings also showed that dopamine drives PLC-ß translocation from the cytoplasm to the plasma membrane in enterocytes for the first time. Overall, these data revealed the role of dopamine in modulating Drosophila gut physiology, offering us new insights for the future gastrointestinal pharmacotherapy of neurodegenerative diseases associated with dopamine deficiency.

Alveolar ridge preservation using autogenous whole-tooth versus demineralized dentin grafts: A randomized controlled clinical trial.

OBJECTIVE: The objective of this randomized controlled trial was to evaluate the radiographic changes and histologic healing following alveolar ridge preservation (ARP) using autogenous whole tooth (AWTG), test group, versus autogenous demineralized dentin graft (ADDG), control group. MATERIAL AND METHODS: Twenty non-molar teeth indicated for extraction were randomized into two groups (n = 10/group). Extracted teeth were prepared into AWTG or ADDG (0.6N HCl; 30 min), inserted into extraction sockets and covered by collagen membranes. Cone-beam computed tomography (CBCT) scans at baseline and six months were compared to assess ridge-dimensional changes. At six months, bone biopsies of engrafted sites were harvested and analyzed histomorphometrically. RESULTS: All sites healed uneventfully. Reduction was 0.85 ± 0.38 mm and 1.02 ± 0.45 mm in ridge width, 0.61 ± 0.20 mm and 0.72 ± 0.27 mm in buccal and 0.66 ± 0.31 mm and 0.56 ± 0.24 mm in lingual ridge height for the AWTG and ADDG group, respectively (p > .05). Histologically, no inflammatory reactions were noticeable and all samples showed new bone formation. Qualitatively, graft-bone amalgamations were more pronounced in ADDG samples. Histomorphometrically, new bone, graft remnants and soft tissue occupied 37.55% ± 8.94%, 17.05% ± 5.58% and 45.4% ± 4.06% of the areas in the AWTG group and 48.4% ± 11.56%, 11.45% ± 4.13% and 40.15% ± 7.73% in the ADDG group of the examined areas, respectively (p > .05). CONCLUSIONS: AWTG and ADDG are similarly effective in ARP. Yet, histologically ADDG seems to demonstrate better graft remodeling, integration and osteoinductive properties.

Consequences of a short-term exposure to a sub lethal concentration of CdO nanoparticles on key life history traits in the fruit fly (Drosophila melanogaster).

Nanoparticles of cadmium oxide (CdO NPs) are among the most common industrial metal oxide nanoparticles. Early adulthood (P1) fruit flies (D. melanogaster) were exposed for 7 days to a sub lethal concentration (0.03 mg CdO NPs/mL, which was 20% of the LC50), spiked into food media to test whether short episodes of CdO NPs exposures early in adult life have long-lasting effects on life history traits such as fecundity well beyond exposure times. All studied life history traits, as well as climbing behavior were adversely affected by exposure to CdO NPs. A blistered wing phenotype was also observed in the non-exposed progeny (F1) of adult flies (P1) and their fecundity was significantly decreased (-50%) compared to the fecundity of non-exposed (control) F1 flies. Expressions of antioxidant enzymes encoding genes; catalase and superoxide dismutase (SOD2) were significantly up regulated in P1 flies compared to control. Expression of metallothionein encoding genes (MTn A-D) were significantly up-regulated in both parent flies (P1) and their progeny (F1) after exposure of P1 flies to CdO NPs compared to non-exposed control flies, suggesting long-term potential effects. Taken together, these findings indicate that short-term exposure to a sub-lethal CdO NP concentration is sufficient to have long-lasting, adverse effects on fruit flies.

Botulinum toxin type A in chronic non-dyshidrotic palmar eczema: A side-by-side comparative study.

New indications are being reported for intradermal botulinum toxin type A (BTX-A) owing to its anti-inflammatory and antipruritic actions. Its successful use for dyshidrotic hand eczema and lichen simplex has been reported in a few cases, while its utility in dry palmar eczema not associated with hyperhidrosis has not yet been investigated. The aim of this study was the assessment of the additive efficacy and tolerability of BTX-A in chronic dry palmar eczema. This prospective non-randomized side-by-side comparative study included 30 cases of chronic bilateral dry palmar eczema with no associated hyperhidrosis. Combined emollients and topical mid-potency steroid on one side were compared with an additive 100 units of intradermal BTX-A on the other side for efficacy and tolerability using both patient- and physician-oriented scores over a period of 6 months. Timing and extent of improvement and relapse were recorded on both sides, together with the frequency of development of side-effects. Both lines were effective and well tolerated, with significantly greater reduction of symptom and sign scores and higher overall patient satisfaction on the side receiving BTX-A, an effect which lasted for a significantly longer duration on this side (4 months) as compared with the other side (1 month). In conclusion, intradermal BTX-A at a dose of 100 units/palm is beneficial and well tolerated in chronic dry palmar eczema. Compared with topical steroid and emollients alone, its addition yielded superior efficacy that was longer lasting and more satisfactory to the patients, while exerting a steroid-sparing effect.

Hormonal modulation of cannibalistic behaviors in mosquito (Culex pipiens) larvae.

Cannibalism has been observed occasionally in a limited number of different animal species, but the underlying mechanisms that foster this behavior are mostly unknown. Here we show that mosquito (Culex pipiens) larvae show this behavior towards conspecifics under certain conditions. Cannibalism was only observed in 4th instar larvae and only in response to starvation. Well fed animals never showed any cannibalistic behavior. Starvation induced cannibalism of Culex 4th instar was predominantly directed towards 3rd instars rather than to 1st or 2nd instar larvae. Specific mandibular structures of these larvae enable this cannibalistic behavior. We could show that treatment with the biogenic amine octopamine, which is known to be involved in the control of starvation and aggression, increased the rate of cannibalism of food-deprived 4th instar larvae significantly. Incubation with the octopamine receptor antagonist phentolamine suppressed this cannibalistic behavior. Moreover, octopamine not only increased the rate of cannibalism, it also induced a shift towards smaller prey. A role of octopamine in this starvation induced behavior was further supported by direct measurements of the total content of this important neuroactive compound. Taken together, we could show that 4th instar mosquito larvae showed cannibalistic behavior after starvation and that this behavior apparently depends on octopamine.

Impaired Wnt signaling in dopamine containing neurons is associated with pathogenesis in a rotenone triggered Drosophila Parkinson's disease model.

Parkinson's disease, which is the one of the most common neurodegenerative movement disorder, is characterized by a progressive loss of dopamine containing neurons. The mechanisms underlying disease initiation and development are not well understood and causative therapies are currently not available. To elucidate the molecular processes during early stages of Parkinson's disease, we utilized a Drosophila model. To induce Parkinson's disease-like phenotypes, we treated flies with the pesticide rotenone and isolated dopamine producing neurons of animals that were at an early disease stage. Transcriptomic analyses revealed that gene ontologies associated with regulation of cell death and neuronal functions were significantly enriched. Moreover, the activities of the MAPK/EGFR- and TGF-ß signaling pathways were enhanced, while the Wnt pathway was dampened. In order to evaluate the role of Wnt signaling for survival of dopaminergic neurons in the disease model, we rescued the reduced Wnt signaling activity by ectopic overexpression of armadillo/ß-catenin. This intervention rescued the rotenone induced movement impairments in the Drosophila model. Taken together, this initial study showed a highly relevant role of Wnt signaling for dopamine producing neurons during pathogenesis in Parkinson's disease and it implies that interfering with this pathway might by a suitable therapeutic option for the future.

The Role of Monoaminergic Neurotransmission for Metabolic Control in the Fruit Fly Drosophila Melanogaster.

Hormones control various metabolic traits comprising fat deposition or starvation resistance. Here we show that two invertebrate neurohormones, octopamine (OA) and tyramine (TA) as well as their associated receptors, had a major impact on these metabolic traits. Animals devoid of the monoamine OA develop a severe obesity phenotype. Using flies defective in the expression of receptors for OA and TA, we aimed to decipher the contributions of single receptors for these metabolic phenotypes. Whereas those animals impaired in octß1r, octß2r and tar1 share the obesity phenotype of OA-deficient (tßh-deficient) animals, the octß1r, octß2r deficient flies showed reduced insulin release, which is opposed to the situation found in tßh-deficient animals. On the other hand, OAMB deficient flies were leaner than controls, implying that the regulation of this phenotype is more complex than anticipated. Other phenotypes seen in tßh-deficient animals, such as the reduced ability to perform complex movements tasks can mainly be attributed to the octß2r. Tissue-specific RNAi experiments revealed a very complex interorgan communication leading to the different metabolic phenotypes observed in OA or OA and TA-deficient flies.

Effect of Transplantation of Bone Marrow Derived Mesenchymal Stem Cells and Platelets Rich Plasma on Experimental Model of Radiation Induced Oral Mucosal Injury in Albino Rats.

Normal tissue damage following radiotherapy is still a major problem in cancer treatment. Therefore, the current work aimed at exploring the possible role of systemically injected bone marrow derived mesenchymal stem cells (BM-MSCs) and/or locally injected platelet rich plasma (PRP) in ameliorating the side effects of ionizing radiation on the rat's tongue. Twelve rats served as control group (N) and 48 rats received a single radiation dose of 13 Gy to the head and neck region; then, they were equally divided into 4 experimental groups: irradiated only (C), irradiated + MSCs (S), irradiated + (PRP) (P), and combined group (PS). Animal scarification occurred in 3 and 7 days after radiation. Then, tongues were dissected and examined histologically and for expression of bcl-2 by RT-PCR. Histological examination of the treated groups (S), (P), and (PS) revealed an obvious improvement in the histological structure of the tongue, compared to group (C), in addition to upregulated expression of bcl-2, indicating decreased apoptotic activity. Conclusion. BM-MSCs and PRP have shown positive effect in minimizing the epithelial atrophy of normal oral mucosa after regional radiotherapy, which was emphasized by decreasing apoptotic activity in these tissues. Nevertheless, combined use of BM-MSCs and PRP did not reveal the assumed synergetic effect in oral tissue protection.

Expression analysis of octopamine and tyramine receptors in Drosophila.

The monoamines octopamine and tyramine, which are the invertebrate counterparts of epinephrine and norepinephrine, transmit their action through sets of G protein-coupled receptors. Four different octopamine receptors (Oamb, Octß1R, Octß2R, Octß3R) and 3 different tyramine receptors (TyrR, TyrRII, TyrRIII) are present in the fruit fly Drosophila melanogaster. Utilizing the presumptive promoter regions of all 7 octopamine and tyramine receptors, the Gal4/UAS system is utilized to elucidate their complete expression pattern in larvae as well as in adult flies. All these receptors show strong expression in the nervous system but their exact expression patterns vary substantially. Common to all octopamine and tyramine receptors is their expression in mushroom bodies, centers for learning and memory in insects. Outside the central nervous system, the differences in the expression patterns are more conspicuous. However, four of them are present in the tracheal system, where they show different regional preferences within this organ. On the other hand, TyrR appears to be the only receptor present in the heart muscles and TyrRII the only one expressed in oenocytes. Skeletal muscles express octß2R, Oamb and TyrRIII, with octß2R being present in almost all larval muscles. Taken together, this study provides comprehensive information about the sites of expression of all octopamine and tyramine receptors in the fruit fly, thus facilitating future research in the field.

The octopamine receptor octß2R is essential for ovulation and fertilization in the fruit fly Drosophila melanogaster.

The biogenic monoamine octopamine is essential for ovulation and fertilization in insects. Release of this hormone from neurons in the thoracoabdominal ganglion triggers ovulation and sperm release from the spermathecae. Here we show that the effects of octopamine on ovulation are mediated by at least two different octopamine receptors. In addition to the Oamb receptor that is present in the epithelium of the oviduct, the octß2R receptor is essential for ovulation and fertilization. Octß2R is widely expressed in the female reproductive tract. Most prominent is expression in the oviduct muscle and the spermathecae. Animals deficient in expression of the receptor show a severe egg-laying defect. The corresponding females have a much larger ovary that is caused by egg retention in the ovary. Moreover, the very few laid eggs are not fertilized, indicating problems in the process of sperm delivery. We assume that octß2R acts in a similar way as ß2-adrenoreceptors in smooth muscles, were activation of this receptor induces an increase in cAMP levels that lead to relaxation of the muscle. Taken together, our findings show that octopaminergic control of ovulation and fertilization is more complex than anticipated and that various receptors located in different cells act together to enable a well-orchestrated activity of the female reproductive system in response to copulation.

Transcriptional regionalization of the fruit fly's airway epithelium.

Although airway epithelia are primarily devoted to gas exchange, they have to fulfil a number of different tasks including organ maintenance and the epithelial immune response to fight airborne pathogens. These different tasks are at least partially accomplished by specialized cell types in the epithelium. In addition, a proximal to distal gradient mirroring the transition from airflow conduction to real gas exchange, is also operative. We analysed the airway system of larval Drosophila melanogaster with respect to region-specific expression in the proximal to distal axis. The larval airway system is made of epithelial cells only. We found differential expression between major trunks of the airways and more distal ones comprising primary, secondary and terminal ones. A more detailed analysis was performed using DNA-microarray analysis to identify cohorts of genes that are either predominantly expressed in the dorsal trunks or in the primary/secondary/terminal branches of the airways. Among these differentially expressed genes are especially those involved in signal transduction. Wnt-signalling associated genes for example are predominantly found in secondary/terminal airways. In addition, some G-protein coupled receptors are differentially expressed between both regions of the airways, exemplified by those activated by octopamine or tyramine, the invertebrate counterparts of epinephrine and norepinephrine. Whereas the OAMB is predominantly found in terminal airway regions, the oct3ßR has higher expression levels in dorsal trunks. In addition, we observed a significant association of both, genes predominantly expressed in dorsal trunks or in primary to terminal branches branches with those regulated by hypoxia. Taken together, this observed differential expression is indicative for a proximal to distal transcriptional regionalization presumably reflecting functional differences in these parts of the fly's airway system.