Search for Gamma-Ray Spectral Lines from Dark Matter Annihilation up to 100 TeV toward the Galactic Center with MAGIC.

Linelike features in TeV γ rays constitute a "smoking gun" for TeV-scale particle dark matter and new physics. Probing the Galactic Center region with ground-based Cherenkov telescopes enables the search for TeV spectral features in immediate association with a dense dark matter reservoir at a sensitivity out of reach for satellite γ-ray detectors, and direct detection and collider experiments. We report on 223 hours of observations of the Galactic Center region with the MAGIC stereoscopic telescope system reaching γ-ray energies up to 100 TeV. We improved the sensitivity to spectral lines at high energies using large-zenith-angle observations and a novel background modeling method within a maximum-likelihood analysis in the energy domain. No linelike spectral feature is found in our analysis. Therefore, we constrain the cross section for dark matter annihilation into two photons to ⟨σv⟩≲5×10^{-28} cm^{3} s^{-1} at 1 TeV and ⟨σv⟩≲1×10^{-25} cm^{3} s^{-1} at 100 TeV, achieving the best limits to date for a dark matter mass above 20 TeV and a cuspy dark matter profile at the Galactic Center. Finally, we use the derived limits for both cuspy and cored dark matter profiles to constrain supersymmetric wino models.

Bounds on Lorentz Invariance Violation from MAGIC Observation of GRB 190114C.

On January 14, 2019, the Major Atmospheric Gamma Imaging Cherenkov telescopes detected GRB 190114C above 0.2 TeV, recording the most energetic photons ever observed from a gamma-ray burst. We use this unique observation to probe an energy dependence of the speed of light in vacuo for photons as predicted by several quantum gravity models. Based on a set of assumptions on the possible intrinsic spectral and temporal evolution, we obtain competitive lower limits on the quadratic leading order of speed of light modification.

Fertility, pregnancy and gynecological outcomes after fetoscopic surgery for congenital diaphragmatic hernia.

STUDY QUESTION: What is the impact of fetoscopic surgery for isolated Congenital Diaphragmatic Hernia (CDH) on future reproductive and gynecological outcomes? SUMMARY ANSWER: We did not observe an increase of obstetric or gynecological problems after fetoscopic surgery nor was there an increased risk for subsequent infertility. WHAT IS KNOWN ALREADY: The reproductive and gynecological outcomes of patients undergoing open maternal-fetal surgery are known. The most relevant counseling items are the elevated risk for uterine dehiscence and rupture (up to 14%). STUDY DESIGN, SIZE, DURATION: Bi-centric study over a 10-year period including 371 women carrying a fetus with isolated CDH either managed expectantly (n = 167) or operated in utero (n = 204). PARTICIPANTS/MATERIALS, SETTING, METHODS: Consenting patients filled out a survey with 23 questions (2 open and 21 multiple choice). Questionnaires were custom designed to obtain information on subsequent reproductive or gynecological problems as well as psychological impact. MAIN RESULTS AND THE ROLE OF CHANCE: The response rate was 40% (147/371). More women in the FETO group attempted a subsequent pregnancy: 70% (62/89) when compared with 47% (27/58) in controls (P = 0.009). This coincided with a longer follow-up in the FETO group (76 versus 59 months; P < 0.001) and a lower survival rate in the index pregnancy (53 versus 72%; P = 0.028). There was no difference in the number of nulliparous or parous women, neither in the conception rate. In total, there were 129 subsequent pregnancies. Nobody reported secondary fertility problems. Four women in the FETO group and one in the control reported a congenital anomaly in a subsequent pregnancy. Twenty-one pregnancies were reported with at least one complication (FETO: 23% (14/60), controls 27% (7/26)). During delivery or in the post-partum period 11 patients reported at least 1 complication (FETO 17% (10/59), controls 4% (1/24)). New onset gynecological problems occurred in 14 participants (10%). None of these events were more likely in one or the other group. Psychological and emotional impacts were frequent in both the FETO (41%) and the control groups (46%) (P = 0.691). LIMITATIONS, REASONS FOR CAUTION: The response rate was 40% (147/371), less than desired. The use of unvalidated self-reported outcomes may skew exact determination of the nature and severity of medical complications. The number of observations for uncommon events was low. The mean follow-up period to detect gynecological complications may be too short. WIDER IMPLICATIONS OF THE FINDINGS: This is the first evidence that fetoscopic surgery for CDH does not compromise future reproductive potential or obstetrical outcome when compared with expectant management. A pregnancy complicated by a serious congenital birth defect, such as CDH, frequently has a measurable psychological impact. STUDY FUNDING/COMPETING INTEREST: The authors have no conflicts to declare. J.D. receives a fundamental clinical research grant of the Fonds Wetenschappelijk Onderzoek - Vlaanderen (FWO; 18.01207). A.C.E. is supported by the Erasmus+Program of the European Union (Framework agreement number 2013-0040; contract 1011990). This was presented at the 61st meeting of the Society of Gynaecologic Investigation, in Florence, March 2014 (F-111).

[Transcervical Embryoscopy after Missed Abortion in Monoamniotic Twins with Discordant Exencephaly]. / Transzervikale Embryoskopie nach verhaltenem Abort in monoamnioten Zwillingen mit diskordanter Exenzephalie.

INTRODUCTION: Monoamniotic twins are considered a cause of high-risk pregnancies. Thereby, discordant malformations do occur rarely. A discordant exencephaly has been described in only a few cases. Transcervical embryoscopy can be performed in cases of monoamniotic twins with missed abortion directly before the abort-curettage. CASE REPORT: The case of a 35-year-old G1/P0 women in the 12(th) week of pregnancy is described. She had a monoamniotic twin pregnancy with discordant exencephaly and missed abortion diagnosed at 11+2 weeks. A transcervical embryoscopy was performed immediately before the abort-curettage and identified the discordant exencephaly and an additional umbilical cord knot of the 2 foetuses as a probable cause for the abortion. DISCUSSION: The transcervical embryoscopy lead in our case report to the diagnosis of a umbilical cord knot in a monoamniotic twin pregnancy with missed abortion. We also identified a discordant exencephaly by embryoscopy. With blunt access to the amniotic cavity, the transcervical embryoscopy applies only a minor additional risk to the abort-curettage. However, it should only be performed when the patient explicitly asks for enhanced diagnostics. CONCLUSION: Transcervical embryoscopy can be performed as an additional diagnostic tool in cases of monoamniotic twins with missed abortion. However, a detailed risk-benefit analysis should be done upfront in consultation with the patient.

Sonographic detection of central nervous system defects in the first trimester of pregnancy.

The fetal central nervous system can already be examined in the first trimester of pregnancy. Acrania, alobar holoprosencephaly, cephaloceles, and spina bifida can confidently be diagnosed at that stage and should actively be looked for in every fetus undergoing first-trimester ultrasound. For some other conditions, such as vermian anomalies and agenesis of the corpus callosum, markers have been identified, but the diagnosis can only be confirmed in the second trimester of gestation. For these conditions, data on sensitivity and more importantly specificity and false positives are lacking, and one should therefore be aware not to falsely reassure or scare expecting parents based on first-trimester findings. This review summarizes the current knowledge of first-trimester neurosonography in the normal and abnormal fetus and gives an overview of which diseases can be diagnosed.

Molecular characterization of disseminated pilocytic astrocytomas.

AIM: Pilocytic astrocytomas represent the most common paediatric tumours of the central nervous system. Dissemination through the ventricular system occurs rarely in patients with pilocytic astrocytomas; however, it is more common in infants with diencephalic tumours, and is associated with a poor outcome. Despite histological similarities with classic pilocytic astrocytomas, it is still unclear whether disseminated pilocytic astrocytomas may have specific molecular features. METHODS: Seventeen disseminated pilocytic astrocytomas were investigated using the molecular inversion probe array and screened for the presence of gene fusions (KIAA1549-BRAF) and mutations (BRAF, RAS and FGFR1). RESULTS: Along with evidence of a constitutive MAPK activation in all cases, the molecular inversion probe array, fluorescence in situ hybridization analysis and mutational study revealed KIAA1549-BRAF fusions in 66% and BRAF(V600E) mutations in 5% of cases. No KRAS, HRAS, NRAS or FGFR1 mutations were found. CONCLUSIONS: disseminated pilocytic astrocytomas showed genetic features similar to classic pilocytic astrocytoma, including a similar incidence of KIAA1549-BRAF fusions, BRAF mutations and a stable genetic profile. Given common activation of the MAPK pathway, the use of specific inhibitors can be hypothesized for the treatment of disseminated pilocytic astrocytomas, along with standard chemo- and/or radiotherapy.

Collagen plug sealing of iatrogenic fetal membrane defects after fetoscopic surgery for congenital diaphragmatic hernia.

OBJECTIVES: To investigate the efficacy of collagen plugs at reducing the risk of preterm premature rupture of membranes (PPROM) after fetoscopic surgery for congenital diaphragmatic hernia (CDH). METHODS: This was a single-center cohort study on all consecutive cases undergoing fetoscopic endoluminal tracheal occlusion (FETO) for severe or moderate CDH, between April 2002 and May 2011 (n = 141). Cases either received a collagen plug for sealing the fetal membrane defect after FETO or did not, depending on the operating surgeon. The principal outcome measure was the time from fetal surgery to PPROM, further referred to as 'latency'. A multivariable Cox regression model was used to investigate the association between collagen plug and latency while adjusting for risk factors for PPROM. RESULTS: Of the 141 cases, 54 (38%) received a collagen plug and 87 (62%) did not. Sixty cases experienced PPROM, 26 among cases with and 34 among cases without a plug (48 vs 39%). The hazard ratio of plug use was 1.29 (95% CI, 0.76-2.19), which does not exclude a potentially increased risk for PPROM when a collagen plug is used. For cases with a plug, 24% had PPROM before balloon removal and 24% had PPROM after elective balloon removal. For cases without a plug, these rates were 30 and 9%, respectively. Perinatal outcomes were similar in both groups. CONCLUSIONS: No evidence was found that collagen plugs reduce the risk of PPROM after FETO for CDH.

In vitro sealing of iatrogenic fetal membrane defects by a collagen plug imbued with fibrinogen and plasma.

OBJECTIVES: We aimed to demonstrate local thrombin generation by fetal membranes, as well as its ability to generate fibrin from fibrinogen concentrate. Furthermore, we aimed to investigate the efficacy of collagen plugs, soaked with plasma and fibrinogen, to seal iatrogenic fetal membrane defects. METHODS: Thrombin generation by homogenized fetal membranes was measured by calibrated automated thrombography. To identify the coagulation caused by an iatrogenic membrane defect, we analyzed fibrin formation by optical densitometry, upon various concentrations of fibrinogen. The ability of a collagen plug soaked with fibrinogen and plasma was tested in an ex vivo model for its ability to seal an iatrogenic fetal membrane defect. RESULTS: Fetal membrane homogenates potently induced thrombin generation in amniotic fluid and diluted plasma. Upon the addition of fibrinogen concentrate, potent fibrin formation was triggered. Measured by densiometry, fibrin formation was optimal at 1250 µg/mL fibrinogen in combination with 4% plasma. A collagen plug soaked with fibrinogen and plasma sealed an iatrogenic membrane defect about 35% better than collagen plugs without these additives (P = 0.037). CONCLUSIONS: These in vitro experiments suggest that the addition of fibrinogen and plasma may enhance the sealing efficacy of collagen plugs in closing iatrogenic fetal membrane defects.

Graft-related complications and biaxial tensiometry following experimental vaginal implantation of flat mesh of variable dimensions.

OBJECTIVE: To compare the occurrence of graft-related complications (GRCs) and biomechanical properties of meshes implanted vaginally and abdominally. DESIGN: In vivo animal experiment. SETTING: Centre for Surgical Technologies, Medical Faculty, KU Leuven, Belgium. POPULATION: Twenty adult parous Texel ewes. METHODS: Sheep were implanted with Gynemesh M, a 28-g/m² polypropylene mesh reinforced with polyglecaprone fibres, under general anaesthesia. Dissection into the rectovaginal septum was performed to accommodate a flat 50 × 50 mm (n = 10) or 35 × 35 mm (n = 10) mesh, which was sutured to the underlying tissues. A 50 × 50 mm mesh was laid over a primarily sutured, full-thickness, 40-mm longitudinal abdominal wall incision. Sacrifice was at 60 days (n = 10) or 90 days (n = 5). MAIN OUTCOME MEASURES: The occurrence of exposure, the degree of contraction and examination of the biomechanical properties of explants with a minimum radius of 32 mm via biaxial tensiometry. RESULTS: Insertion of a 50 × 50 mm mesh led to exposures in 30% (3/10) of cases, and the average contraction rate was 52 ± 14%. In the 35 × 35 mm implants, there were no exposures, and the contraction rate was 25 ± 26.3%. Vaginal explants with no GRCs and of sufficient size had biomechanical properties that were comparable with those of abdominal explants. CONCLUSION: Vaginal mesh insertion is associated with GRCs, such as exposure and contraction. Although other factors probably play a role, this study illustrates that mesh size may also induce these complications. In a vaginal surgery model, clinically occurring GRCs can be reproduced. In addition, biomechanics of uncomplicated vaginal explants are comparable with those measured on abdominal explants.

Compliance with hand hygiene in patients with meticillin-resistant Staphylococcus aureus and extended-spectrum ß-lactamase-producing enterobacteria.

Hand hygiene is considered to be the single most effective measure to prevent healthcare-associated infection. Although there have been several reports on hand hygiene compliance, data on patients with multidrug-resistant (MDR) organisms in special isolation conditions are lacking. Therefore, we conducted a prospective observational study of indications for, and compliance with, hand hygiene in patients colonised or infected with meticillin-resistant Staphylococcus aureus (MRSA) or extended-spectrum ß-lactamase (ESBL)-producing enterobacteria in surgical intensive and intermediate care units. Hand disinfectant used during care of patients with MRSA was measured. Observed daily hand hygiene indications were higher in MRSA isolation conditions than in ESBL isolation conditions. Observed compliance rates were 47% and 43% for the MRSA group and 54% and 51% for the ESBL group in the surgical intensive care unit and the intermediate care unit, respectively. Compliance rates before patient contact or aseptic tasks were significantly lower (17-47%) than after contact with patient, body fluid or patient's surroundings (31-78%). Glove usage instead of disinfection was employed in up to 100% before patient contact. However, compliance rates calculated from disinfectant usage were two-fold lower (intensive care: 24% vs 47%; intermediate care: 21% vs 43%). This study is the first to provide data on hand hygiene in patients with MDR bacteria and includes a comparison of observed and calculated compliance. Compliance is low in patients under special isolation conditions, even for the indications of greatest impact in preventing healthcare-associated infections. These data may help to focus measures to reduce transmission of MDR bacteria and improve patient safety.

[Efficacy of a combination therapy with vitamins B6, B12 and folic acid for general feeling of ill-health. Results of a non-interventional post-marketing surveillance study]. / Wirksamkeit einer Vitamin-B6-, -B12- und Folsäure-Kombinationstherapie bei Befindlichkeitsstörungen. Ergebnisse einer Anwendungsbeobachtung.

OBJECTIVE: In the present non-interventional postmarketing surveillance study, patients with symptoms of an inadequate supply of vitamins were tested for how a treatment with a combination vitamin injection consisting of vitamins B6, B12 and folic acid affects mood and fitness. The evaluation of the efficacy and tolerability as well as the documentation of adverse drug reactions were carried out by the physician. METHODS: The patient collective included 1430 patients (70.8% women, average age 67.1 years, average BMI 25.5 kg/m2). The average duration of treatment was 4.5 weeks with an average of 8.3 intramuscular injections. The principal method for determining the efficacy was the self-assessment scale of well-being (Bf-S) according to Zerssen (sum score with a value range between 0 and 56 points). RESULTS: The sum score of the Bf-S decreased from 37.5 (+/-10.1) points at admission to 15.6 (+/- 9.4) points after four weeks of treatment. The subjective impression improved correspondingly in 96.3% of the patients. The improvement of the Bf-S was equally good in women and men. The number of injections correlated with the improvement in the sum score. The tolerability was mainly rated as very good or good. CONCLUSIONS: Eight vitamin infections over four weeks led to a clear improvement in the mood and vitality of patients with symptoms of intracellular vitamin B deficiency.

Investigation of the functional properties and regulation of three glutamine synthetase-like genes in Streptomyces coelicolor A3(2).

Streptomyces coelicolor A3(2) has three additional glnA-type genes besides the glutamine synthetase genes glnA (encoding GSI) and glnII (encoding GSII). The aim of this work was to characterize their functional properties and regulation. Sequence analyses revealed that GlnA2, GlnA3, and GlnA4 are dissimilar to S. coelicolor GSI and lack highly conserved amino acid residues involved in catalysis. In heterologous expression experiments, glnA2, glnA3, and glnA4, in contrast to glnA and glnII, were not capable of complementing the L-glutamine auxotrophy of an Escherichia coli glnA mutant. The lack of a conserved sequence motif reflecting adenylylation control of enzyme activity suggests that GlnA2, GlnA3, and GlnA4 are not regulated via adenylyltransferase-mediated modification. In DNA-binding assays, the OmpR-like regulator of nitrogen metabolism GlnRII, which interacts with the glnA and glnII promoters, did not bind to the upstream regions of glnA2, glnA3, and glnA4. These findings support the conclusion that glnA2, glnA3, and glnA4 are not directly involved in L-glutamine synthesis and nitrogen assimilation and are not subject to nitrogen control in S. coelicolor. The glnA3 gene product is similar to FluG, which is required for asexual sporulation in Aspergillus nidulans. However, inactivation of glnA3 does not block morphological differentiation in S. coelicolor.

The GlnD and GlnK homologues of Streptomyces coelicolor A3(2) are functionally dissimilar to their nitrogen regulatory system counterparts from enteric bacteria.

Glutamine synthetase I (GSI) enzyme activity in Streptomyces coelicolor is controlled post-translationally by the adenylyltransferase (GlnE) as in enteric bacteria. Although other homologues of the Escherichia coli Ntr system (glnK, coding for a PII family protein; and glnD, coding for an uridylyltransferase) are found in the S. coelicolor genome, the regulation of the GSI activity was found to be different. The functions of glnK and glnD were analysed by specific mutants. Surprisingly, biochemical assay and two-dimensional PAGE analysis showed that modification of GSI by GlnE occurs normally in all mutant strains, and neither GlnK nor GlnD are required for the regulation of GlnE in response to nitrogen stimuli. Analysis of the post-translational regulation of GlnK in vivo by two-dimensional PAGE and mass spectrometry indicated that it is subject to both a reversible and a non-reversible modification in a direct response to nitrogen availability. The irreversible modification was identified as removal of the first three N-terminal amino acid residues of the protein, and the reversible modification as adenylylation of the conserved tyro-sine 51 residue that is known to be uridylylated in E. coli. The glnD insertion mutant expressing only the N-terminal half of GlnD was capable of adenylylating GlnK, but was unable to perform the reverse deadenylylation reaction in response to excess ammonium. The glnD null mutant completely lacked the ability to adenylylate GlnK. This work provides the first example of a PII protein that is modified by adenylylation, and demonstrates that this reaction is performed by a homologue of GlnD, previously described only as a uridylyltransferase enzyme.

Two transcriptional regulators GlnR and GlnRII are involved in regulation of nitrogen metabolism in Streptomyces coelicolor A3(2).

Streptomyces coelicolor has an unusually large arsenal of glutamine synthetase (GS) enzymes: a prokaryotic GSI-beta-subtype enzyme (encoded by glnA), three annotated glnA-like genes of the GSI-alpha-subtype and a eukaryote-like glutamine synthetase II (encoded by glnII). Under all tested conditions, GSI was found to represent the dominant glutamine synthetase activity. A significant heat-labile GSII activity, which is very low to undetectable in liquid-grown cultures, was only detected in morphologically differentiating S. coelicolor cultures. Analysis of glnA and glnII transcription by S1 nuclease mapping and egfp fusions revealed that, on nitrogen-limiting solid medium, glnII but not glnA expression is upregulated. An OmpR-like regulator protein, GlnR, has previously been implicated in transcriptional control of glnA expression. Gel retardation analysis revealed that GlnR is a DNA-binding protein, which interacts with the glnA promoter. It is not autoregulatory and does not bind to the upstream regions of the glnA-like genes of the alpha-subfamily, nor to the glnII promoter in vitro. A second GlnR target was identified upstream of the amtB gene, encoding a putative ammonium transporter. amtB forms an operon with glnK (encoding a PII protein) and glnD (encoding a putative PII nucleotidylyltransferase) shown by S1 nuclease protection analysis and reverse transcription-polymerase chain reaction (RT-PCR). An amtB and glnA promoter alignment revealed a putative GlnR operator structure. Downstream of glnII, a gene encoding for another OmpR-like regulator, GlnRII, was identified, with strong similarity to GlnR. Gel shifts with GlnRII showed that the promoters recognized by GlnR are also targets of GlnRII. However, GlnRII also interacted with the glnII upstream region. Only inactivation of glnR resulted in a glutamine auxotrophic phenotype, whereas the glnRII mutant can grow on minimal medium without glutamine.

Transcriptional analysis of the gene for glutamine synthetase II and two upstream genes in Streptomyces coelicolor A3(2).

The glutamine synthetase II (GSII, encoded by glnII) activity detectable in crude extracts from Streptomyces coelicolor is low compared to the activity of glutamine synthetase I (GSI, encoded by glnA) and to that of GSII from S. viridochromogenes. We have identified and sequenced a 3.9-kb BglII-BamHI fragment carrying the glutamine synthetase II gene (glnII) from S. coelicolor. Besides glnII, this region contains four ORFs (orf1-orf4). While homologues of orf1 and orf2 were also found in the glnII region of the S. viridochromogenes chromosome, this was not the case for orf3 and orf4, which encode a putative hydrolase and a transcriptional regulator (Ptr) of the MarR family, respectively. High-resolution S1 nuclease mapping showed that the S. coelicolor glnII gene is expressed from two overlapping promoters. The first comprises a vegetative promoter sequence and the second contains sequence elements that are recognized by Esigma31. Similar promoter structures were found upstream of the S. viridochromogenes glnII gene. The involvement of ptr in glnII regulation was studied by gel retardation assays. Recombinant Ptr interacted with the upstream region of ptr, but not with the promoter region of glnII. A ptr gene replacement mutant (S. coelicolor IP) was also constructed. RT-PCR analysis of RNA from wild-type S. coelicolor and the IP mutant demonstrated that expression of orf3 depends on Ptr. Thus, the difference in gene organization between S. coelicolor and S. viridochromogenes is not responsible for the difference in GSII activity.

Molecular cloning, expression analysis and iron metal cofactor characterisation of a superoxide dismutase from Toxoplasma gondii.

A genomic region of 12 kb encompassing the gene encoding the superoxide dismutase (SOD) of Toxoplasma gondii has been cloned. The gene contains four exons of 121, 42, 381 and 59 bp which are separated by three introns of 321, 202, and 577 bp, respectively. The open reading frame can be translated into a protein of 201 amino acids with a molecular mass of 22.6 kDa. Alignment indicated that it is a FeSOD, a type only found in bacteria, protozoa and chloroplast of higher plants. Recombinant SOD was expressed in a Escherichia coli double mutant lacking both MnFeSOD and FeSODs. The presence of iron as metal cofactor was confirmed by measurements of iron by absorption mass spectrometry and electron paramagnetic resonance studies. Semi-quantitative reverse transcribed polymerase chain reaction experiments showed a similar amount of SOD transcripts in two developmental stages of T. gondii. Antibodies raised against the purified recombinant protein detected SOD protein in both bradyzoite and tachyzoite forms suggesting this SOD might be essential for the intracellular growth of both developmental stages. Southern blot analysis indicated that SOD occured as a single copy gene in T. gondii genome.

Functional expression of a locust visual pigment in transgenic Drosophila melanogaster.

The cDNA encoding a visual pigment of the locust Schistocerca gregaria has been inserted into the germline of the ninaE mutant of Drosophila melanogaster by P-element-mediated transformation. Functional expression has been documented by recording light-regulated electroretinograms in transgenic flies. The spectral properties of the expressed visual pigment were determined with detergent-solubilized material, prepared from the eyecups of the transgenic D. melanogaster. The recombinant locust pigment, as well as the genuine pigment of the fruitfly (Rh1) that served as a control for transformation/expression, showed photoreversibility between the pigment and metapigment forms. The absorptions of the difference spectra identify the locust visual pigment as a short wavelength-absorbing, blue-light-sensitive photoreceptor. The absorption maxima are similar to those recorded on living locust animals. These results show that, although locust visual pigments contain 11-cis retinal as chromophore, the expressed protein is able to adopt 3-hydroxyretinal that is provided by the transgenic fruitflies. The electrophysiological recordings reveal that the locust visual pigment is able to induce phototransduction in the fruitfly. The reported results have two important consequences: On the one hand, the binding site of the locust opsin is apparently able to interact with the 3-hydroxyretinal from Drosophila in a way that the biological signal generated by the photoisomerization of the chromophore can be used by the protein to adopt a physiologically active conformation. On the other hand, despite the relatively large phylogenetic distance between both insect species, the extent of conservation between the protein domains thought to be involved in G-protein activation is striking.

Nitrogen metabolism in Streptomyces coelicolor A3(2): modification of glutamine synthetase I by an adenylyltransferase.

An internal adenylyltransferase gene (glnE) fragment from Streptomyces coelicolor was amplified using heterologous PCR primers derived from consensus motifs. The sequence had significant similarity to bacterial glnE genes, and included a motif typical of the C-terminal adenylyltransferase domain of glnE. glnE from S. coelicolor lies on the Asel-C fragment of the chromosome and is localized near glnA (encoding glutamine synthetase I, GSI) and glnII (encoding GSII). To analyse the function of glnE in S. coelicolor, glnE (S. coelicolor E4) and glnA (S. coelicolor HT107) gene replacement mutants were constructed. The GSI activity of the glnE mutant was not down-regulated after an ammonium shock. However, the GSI activity of the wild-type cells decreased to 60% of the original activity. The glnA mutant is not glutamine auxotrophic, but in the gamma-glutamyltransferase assay no GSI activity was detected in unshifted and shifted HT107 cells. By snake venom phosphodiesterase treatment the GSI activity in the wild-type can be reconstituted, whereas no alteration is observed in the E4 mutant. Additionally, the loss of short-term GSI regulation in the E4 mutant was accompanied by an increased glutamine:glutamate ratio.

Genetic analysis of resistance to fenpropimorph in Aspergillus niger.

Resistance to the morpholine-fungicide fenpropimorph was studied in Aspergillus niger and A. nidulans. Mass selection of conidia of A. nidulans on agar amended with the fungicide at different concentrations did not yield of resistant mutants, even after UV-treatment of the conidia. In contrast, similar experiments with A. niger generated many fenpropimorph-resistant mutants. The mutants displayed cross-resistance to fenpropidin and generally showed wild-type sensitivity to the unrelated toxicants fenarimol and cycloheximide. Genetic analysis of fenpropimorph resistance in A. niger was carried out by means of the parasexual cycle. In the mutants tested, two genes located on linkage group II were involved in fenpropimorph resistance. Dominance tests showed that resistance to fenpropimorph in A. niger is recessive.