Isolation and characterisation of Heterorhabditis spp. (Nematoda: Heterorhabditidae) from Hungary, Estonia and Denmark

Targeted surveys were conducted for the entomopathogenic nematode Heterorhabditis in areas of Denmark, Estonia and Hungary. Isolateswere identiŽ ed by IEF, PCR and cross-fertilitytests as belonging to three distinct taxonomic groups: H. bacteriophora, the north-west European (NWE) type of H. megidis and the Irish type of Heterorhabditis. The Irish and NWE types of Heterorhabditis were both present in Denmark (at six and four sites, respectively),while only the NWE type was recovered in Estonia. H. bacteriophora was the dominant heterorhabditididentiŽ ed in Hungary (ten sites), but the Irish typewas also detected at two sites. This is the Ž rst report of the Irish type of Heterorhabditis on continental Europe. Co-occurrence of two Heterorhabditis types at a single site was noted in Denmark (Irish and NWE) and in Hungary (Irish and H. bacteriophora). Heterorhabditiswas recovered at 38.5% of sites (n = 26) in Denmark (north coast of Sjælland), 27.3% of the coastal sites (n = 22) in Estonia, and 32.6% of sites (n = 46) in Hungary

Female presence is required for male sexual maturity in the nematode Steinernema longicaudum

Although cheap compared to eggs, sperm are still costly to produce and may deteriorate if stored 1 and 2. Therefore, selection should favour the ability of males to adjust the quantity or quality of sperm in response to fertilisation opportunities. The males of some species of insect, for instance, may adjust testis size, sperm number or ejaculate composition in response to the social environment [3]. Males of certain rodents, fish and insects increase sperm production in response to female presence 4, 5 and 6. However, males typically have at least some sperm always ready. Here, we show that in the insect-killing nematode Steinernema longicaudum, males that develop alone contain no sperm. Only after several hours with a female, but not another male, sperm are produced so that progeny can be sired

Systemic RNAi mediated gene silencing in the anhydrobiotic nematode Panagrolaimus superbus

<p>Abstract</p> <p>Background</p> <p>Gene silencing by RNA interference (RNAi) is a powerful tool for functional genomics. Although RNAi was first described in <it>Caenorhabditis elegans</it>, several nematode species are unable to mount an RNAi response when exposed to exogenous double stranded RNA (dsRNA). These include the satellite model organisms <it>Pristionchus pacificus </it>and <it>Oscheius tipulae</it>. Available data also suggest that the RNAi pathway targeting exogenous dsRNA may not be fully functional in some animal parasitic nematodes. The genus <it>Panagrolaimus </it>contains bacterial feeding nematodes which occupy a diversity of niches ranging from polar, temperate and semi-arid soils to terrestrial mosses. Thus many <it>Panagrolaimus </it>species are adapted to tolerate freezing and desiccation and are excellent systems to study the molecular basis of environmental stress tolerance. We investigated whether <it>Panagrolaimus </it>is susceptible to RNAi to determine whether this nematode could be used in large scale RNAi studies in functional genomics.</p> <p>Results</p> <p>We studied two species: <it>Panagrolaimus </it>sp. PS1159 and <it>Panagrolaimus superbus</it>. Both nematode species displayed embryonic lethal RNAi phenotypes following ingestion of <it>Escherichia coli </it>expressing dsRNA for the <it>C. elegans </it>embryonic lethal genes <it>Ce-lmn-1 </it>and <it>Ce-ran-4</it>. Embryonic lethal RNAi phenotypes were also obtained in both species upon ingestion of dsRNA for the <it>Panagrolaimus </it>genes <it>ef1b </it>and <it>rps-2</it>. Single nematode RT-PCR showed that a significant reduction in mRNA transcript levels occurred for the target <it>ef1b </it>and <it>rps-2 </it>genes in RNAi treated <it>Panagrolaimus </it>sp. 1159 nematodes. Visible RNAi phenotypes were also observed when <it>P. superbus </it>was exposed to dsRNA for structural genes encoding contractile proteins. All RNAi phenotypes were highly penetrant, particularly in <it>P. superbus</it>.</p> <p>Conclusion</p> <p>This demonstration that <it>Panagrolaimus </it>is amenable to RNAi by feeding will allow the development of high throughput methods of RNAi screening for <it>P. superbus</it>. This greatly enhances the utility of this nematode as a model system for the study of the molecular biology of anhydrobiosis and cryobiosis and as a possible satellite model nematode for comparative and functional genomics. Our data also identify another nematode infraorder which is amenable to RNAi and provide additional information on the diversity of RNAi phenotypes in nematodes.</p

Characterisation of the entomopathogenic nematode Heterorhabditk (Nematoda : Heterorhabditidae) from Ireland and Britain by molecular and cross-breeding techniques,and the occurrence of the genus in these islands

Soil surveys were conducted in Ireland and Britain for Heterorhabditis nematodes. Soil samples taken from sandy locations were baited with Galleria rnellonella larvae. Heterorhabditis was detected at 18/169 sites in Ireland, 21.5 1 sites in the North of Scotland, and 9/20 sites in the South of Wales. All of the positive sites were coastal; the genus was not detected at any of the 40 inland sites sampled. All of the 76 isolates recovered in these surveys were identified, using isoelectric focusing, DNA estriction and cross-breeding methods, as belonging to the Irish Group of Heterorhabditis. No member of the North-West European Group of Heterorhabditis was recovered. However, an isolate recovered by other workers and originating in the south of England was identified as belonging to that group. Members of the Irish Group did not generally interbreed with embers of the "E Group from either England or continental Europe, though fertile infective juveniles resulted in a minority (3/15) of intergroup crosses

Anhydrobiosis and Freezing-Tolerance:Adaptations That Facilitate the Establishment of Panagrolaimus Nematodes in Polar Habitats

<div><p>Anhydrobiotic animals can survive the loss of both free and bound water from their cells. While in this state they are also resistant to freezing. This physiology adapts anhydrobiotes to harsh environments and it aids their dispersal. <i>Panagrolaimus davidi</i>, a bacterial feeding anhydrobiotic nematode isolated from Ross Island Antarctica, can survive intracellular ice formation when fully hydrated. A capacity to survive freezing while fully hydrated has also been observed in some other Antarctic nematodes. We experimentally determined the anhydrobiotic and freezing-tolerance phenotypes of 24 <i>Panagrolaimus</i> strains from tropical, temperate, continental and polar habitats and we analysed their phylogenetic relationships. We found that several other <i>Panagrolaimus</i> isolates can also survive freezing when fully hydrated and that tissue extracts from these freezing-tolerant nematodes can inhibit the growth of ice crystals. We show that <i>P. davidi</i> belongs to a clade of anhydrobiotic and freezing-tolerant panagrolaimids containing strains from temperate and continental regions and that <i>P. superbus</i>, an early colonizer at Surtsey island, Iceland after its volcanic formation, is closely related to a species from Pennsylvania, USA. Ancestral state reconstructions show that anhydrobiosis evolved deep in the phylogeny of <i>Panagrolaimus</i>. The early-diverging <i>Panagrolaimus</i> lineages are strongly anhydrobiotic but weakly freezing-tolerant, suggesting that freezing tolerance is most likely a derived trait. The common ancestors of the <i>davidi</i> and the <i>superbus</i> clades were anhydrobiotic and also possessed robust freezing tolerance, along with a capacity to inhibit the growth and recrystallization of ice crystals. Unlike other endemic Antarctic nematodes, the life history traits of <i>P. davidi</i> do not show evidence of an evolved response to polar conditions. Thus we suggest that the colonization of Antarctica by <i>P. davidi</i> and of Surtsey by <i>P. superbus</i> may be examples of recent “ecological fitting” of freezing-tolerant anhydrobiotic propagules to the respective abiotic conditions in Ross Island and Surtsey.</p></div

Peri-operative red blood cell transfusion in neonates and infants: NEonate and Children audiT of Anaesthesia pRactice IN Europe: A prospective European multicentre observational study

BACKGROUND: Little is known about current clinical practice concerning peri-operative red blood cell transfusion in neonates and small infants. Guidelines suggest transfusions based on haemoglobin thresholds ranging from 8.5 to 12 g dl-1, distinguishing between children from birth to day 7 (week 1), from day 8 to day 14 (week 2) or from day 15 (≥week 3) onwards. OBJECTIVE: To observe peri-operative red blood cell transfusion practice according to guidelines in relation to patient outcome. DESIGN: A multicentre observational study. SETTING: The NEonate-Children sTudy of Anaesthesia pRactice IN Europe (NECTARINE) trial recruited patients up to 60 weeks' postmenstrual age undergoing anaesthesia for surgical or diagnostic procedures from 165 centres in 31 European countries between March 2016 and January 2017. PATIENTS: The data included 5609 patients undergoing 6542 procedures. Inclusion criteria was a peri-operative red blood cell transfusion. MAIN OUTCOME MEASURES: The primary endpoint was the haemoglobin level triggering a transfusion for neonates in week 1, week 2 and week 3. Secondary endpoints were transfusion volumes, 'delta haemoglobin' (preprocedure - transfusion-triggering) and 30-day and 90-day morbidity and mortality. RESULTS: Peri-operative red blood cell transfusions were recorded during 447 procedures (6.9%). The median haemoglobin levels triggering a transfusion were 9.6 [IQR 8.7 to 10.9] g dl-1 for neonates in week 1, 9.6 [7.7 to 10.4] g dl-1 in week 2 and 8.0 [7.3 to 9.0] g dl-1 in week 3. The median transfusion volume was 17.1 [11.1 to 26.4] ml kg-1 with a median delta haemoglobin of 1.8 [0.0 to 3.6] g dl-1. Thirty-day morbidity was 47.8% with an overall mortality of 11.3%. CONCLUSIONS: Results indicate lower transfusion-triggering haemoglobin thresholds in clinical practice than suggested by current guidelines. The high morbidity and mortality of this NECTARINE sub-cohort calls for investigative action and evidence-based guidelines addressing peri-operative red blood cell transfusions strategies. TRIAL REGISTRATION: ClinicalTrials.gov, identifier: NCT02350348

Expression of horseradish peroxidase in transgenic tobacco

Peroxidases are common oxidoreductases present in plants, animals and micro-organisms. Plant peroxidases are classified as basic, neutral or acidic enzymes, depending on their profiles of elution during ion-exchange column chromatography or isoelectric points [ 11. Horseradish (Amtoru~hru sticuna) peroxidases (HRPs; EC 1.1 1.1.7), are probably the best characterized of these enzymes. They are believed to be involved in plant responses to a number of biotic and abiotic stresses, notably in the disruption of free radicals and active derivatives of oxygen. The effects of these molecules have been well described [2], and in general the presence of these compounds are ‘highly destructive’ for cell metabolism. However, these oxygen derivatives are involved in halogenation and hydroxylation reactions in peroxisomes and in the cell wall, suggesting that the plant cell needs a fine regulation between production and destruction of oxygen radicals. A key to the comprehension of the role of peroxidase activity in this and other stress responses could be the study of the effect of modified expression and targeting of peroxidase activity in transgenic plants. The present report describes the production of such tobacco plants using a synthetic HRP gene [ 31, with a range of regulatory and targeting sequences

Characterisation of the entomopathogenic nematode Heterorhabditk (Nematoda : Heterorhabditidae) from Ireland and Britain by molecular and cross-breeding techniques,and the occurrence of the genus in these islands

Soil surveys were conducted in Ireland and Britain for Heterorhabditis nematodes. Soil samples taken from sandy locations were baited with Galleria rnellonella larvae. Heterorhabditis was detected at 18/169 sites in Ireland, 21.5 1 sites in the North of Scotland, and 9/20 sites in the South of Wales. All of the positive sites were coastal; the genus was not detected at any of the 40 inland sites sampled. All of the 76 isolates recovered in these surveys were identified, using isoelectric focusing, DNA estriction and cross-breeding methods, as belonging to the Irish Group of Heterorhabditis. No member of the North-West European Group of Heterorhabditis was recovered. However, an isolate recovered by other workers and originating in the south of England was identified as belonging to that group. Members of the Irish Group did not generally interbreed with embers of the "E Group from either England or continental Europe, though fertile infective juveniles resulted in a minority (3/15) of intergroup crosses

Characterisation of the entomopathogenic nematode Heterorhabditk (Nematoda : Heterorhabditidae) from Ireland and Britain by molecular and cross-breeding techniques,and the occurrence of the genus in these islands

Soil surveys were conducted in Ireland and Britain for Heterorhabditis nematodes. Soil samples taken from sandy locations were baited with Galleria rnellonella larvae. Heterorhabditis was detected at 18/169 sites in Ireland, 21.5 1 sites in the North of Scotland, and 9/20 sites in the South of Wales. All of the positive sites were coastal; the genus was not detected at any of the 40 inland sites sampled. All of the 76 isolates recovered in these surveys were identified, using isoelectric focusing, DNA estriction and cross-breeding methods, as belonging to the Irish Group of Heterorhabditis. No member of the North-West European Group of Heterorhabditis was recovered. However, an isolate recovered by other workers and originating in the south of England was identified as belonging to that group. Members of the Irish Group did not generally interbreed with embers of the "E Group from either England or continental Europe, though fertile infective juveniles resulted in a minority (3/15) of intergroup crosses