scholarly journals Viability of Oomycete Propagules Following Ingestion and Excretion by Fungus Gnats, Shore Flies, and Snails

Plant Disease ◽  
2009 ◽  
Vol 93 (7) ◽  
pp. 720-726 ◽  
Author(s):  
Naveen Hyder ◽  
Michael D. Coffey ◽  
Michael E. Stanghellini
Keyword(s):  
Digestive Tract ◽  
Phytophthora Capsici ◽  
Pythium Aphanidermatum ◽  
Phytophthora Ramorum ◽  
Larval Stages ◽  
Pythium Splendens ◽  
Fungus Gnats ◽  
Detached Leaves ◽  
Rapid Dissemination ◽  
The Impact

Sporangia of Phytophthora capsici and P. nicotianae, as well as hyphal swellings of Pythium splendens, P. sylvaticum, and P. ultimum, were ingested by adult shore flies but none were viable after passing through the digestive tract. Oospores of Pythium aphanidermatum retained their viability following ingestion by adult shore flies. Larval stages of fungus gnats and shore flies ingested sporangia of Phytophthora capsici, P. nicotianae, and P. ramorum, but they were not viable upon excretion. In contrast, hyphal swellings of Pythium splendens, P. sylvaticum, and P. ultimum, chlamydospores of Phytophthora ramorum, and oospores of Pythium aphanidermatum, retained their viability after passage through the digestive tract of these larvae. Snails were capable of ingesting and excreting viable sporangia and chlamydospores of P. ramorum, which upon excretion infected detached leaves. Although the impact of larvae and snails in the rapid dissemination of pathogen propagules is unknown, this work does highlight the possibility that some often-ignored animal–fungus interactions should be considered in long-range dispersal of pathogen propagules via food webs.

scholarly journals Sporangia Production Over Time by Phytophthora ramorum on Rhododendron ‘Cunningham’s White’ After Placement at Different Relative Humidities

2018 ◽  
Vol 108 (6) ◽  
pp. 721-729
Author(s):  
Paul W. Tooley ◽  
Marsha Browning
Keyword(s):  
Relative Humidity ◽  
Predictive Models ◽  
Phytophthora Ramorum ◽  
Risk Assessments ◽  
Detached Leaves ◽  
Sporulation Capacity ◽  
Management Recommendations ◽  
The Impact ◽  
Over Time ◽  
Pest Risk

We examined the impact of relative humidity (RH) on Phytophthora ramorum sporangia production on Rhododendron ‘Cunningham’s White’. When diseased plants were maintained under continuous moisture in a mist tent, sporangia were collected from some plants for 22 weeks. More than 3,000 sporangia/leaf/week were collected over the first 3 weeks but levels declined to <100 sporangia/leaf/week after 7 weeks. We also examined the impact of drying on P. ramorum sporangia production. Diseased, detached leaves were maintained in humidity chambers (100, 96.2, 84.5, 74.9, and 56.2% RH) for up to 9 weeks and removed weekly to assess sporulation. For comparison, diseased leaves were harvested from plants maintained with dry foliage or subjected to 10 h of simulated dew nightly. All leaves supported sporulation following 5 weeks at 100% RH, 3 weeks at 96.2% RH, and 1 week at 84.5% RH. All leaves collected from plants subjected to nightly dew supported sporulation for 3 weeks; however, only 66.7% of leaves collected from plants with dry foliage supported sporulation after 1 week. Knowledge of the effects of RH levels on P. ramorum sporulation capacity will prove useful in terms of disease management recommendations and for development of predictive models and pest risk assessments.

scholarly journals Pharmacologic modulation of 5-fluorouracil by folinic acid and high-dose pyridoxine for treatment of patients with digestive tract carcinomas

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
David Machover ◽  
Wathek Almohamad ◽  
Vincent Castagné ◽  
Christophe Desterke ◽  
Léa Gomez ◽  
...  
Keyword(s):  
Folinic Acid ◽  
Digestive Tract ◽  
Vitamin B6 ◽  
Colorectal Adenocarcinoma ◽  
High Dose ◽  
High Concentration ◽  
Carcinoma Of The Esophagus ◽  
Pancreas Adenocarcinoma ◽  
The Impact ◽  
High Dose Vitamin

AbstractSupplementation of cancer cells exposed to 5-fluorouracil (FUra) and folinic acid (FA) with high concentration pyridoxal 5′-phosphate, the cofactor of vitamin B6, potentiates the cytotoxicity of FUra in a synergistic interaction mode. We report a pilot study in 13 patients with previously untreated advanced carcinoma of the digestive tract to assess the impact of high-dose pyridoxine (PN) on the antitumor activity of regimens comprising FUra and FA. Five patients had colorectal adenocarcinoma (CRC); 5 had pancreas adenocarcinoma (PC); and 3 had squamous cell carcinoma of the esophagus (EC). Patients with CRC and with PC received oxaliplatin, irinotecan, FUra and FA, and patients with EC had paclitaxel, carboplatin, FUra and FA. PN iv from 1000 to 3000 mg/day preceded each administration of FA and FUra. Eleven patients responded. Two patients with CRC attained CRs and 3 had PRs with reduction rates ≥ 78%. Two patients with PC attained CRs, and 2 had PRs with reduction rates ≥ 79%. Responders experienced disappearance of most metastases. Of 3 patients with EC, 2 attained CRs. Median time to attain a response was 3 months. Unexpected toxicity did not occur. Results suggest that high-dose vitamin B6 enhances antitumor potency of regimens comprising FUra and FA.

scholarly journals Impact of a dedicated multidisciplinary meeting on the management of superficial cancers of the digestive tract

2018 ◽  
Vol 06 (12) ◽  
pp. E1470-E1476 ◽  
Author(s):  
Solène Dermine ◽  
Maximilien Barret ◽  
Caroline Prieux ◽  
Sophie Ribière ◽  
Sarah Leblanc ◽  
...  
Keyword(s):  
Digestive Tract ◽  
Endoscopic Resection ◽  
Gastrointestinal Endoscopy ◽  
Lesion Size ◽  
Concordance Rate ◽  
Resection Rate ◽  
Tertiary Referral Center ◽  
Multidisciplinary Meeting ◽  
The Mean ◽  
The Impact

Abstract Background The recent development of endoscopic resection for superficial gastrointestinal cancers could justify the need for a dedicated oncological multidisciplinary meeting (MDM). The aim of our study was to evaluate the impact of the dedicated MDM on the management of superficial cancers of the digestive tract. Methods A dedicated MDM was developed at our tertiary referral center. A retrospective review of the MDM conclusions for all patients referred from March 2015 to March 2017 was performed. Outcomes measurements were the outcomes of endoscopic resection, and the concordance rate between the MDM recommendations, European Society of Gastrointestinal Endoscopy (ESGE) guidelines, and final patient management. Results In total, 153 patients with a median age of 69 years were included. Half of the patients had major comorbidities. The mean lesion size was 25 mm, and R0 and curative resection rate were 73.9 % and 56.9 %, respectively. Forty-three patients had an indication for surgery after endoscopic resection. The concordance rate between ESGE guidelines and MDM recommendation was 92.2 %, and 12 patients did not receive the treatment recommended due to comorbidities. Conclusion A MDM dedicated to superficial tumors helped tailor the ESGE guidelines to each patient in order to avoid unnecessary surgery.

scholarly journals Occurrence of Tetracampos ciliotheca and Proteocephalus glanduligerus in Clarias gariepinus (Burchell, 1822) collected from the Vaal Dam, South Africa

2013 ◽  
Vol 80 (1) ◽  
Author(s):  
Grace Madanire-Moyo ◽  
Annemariè Avenant-Oldewage
Keyword(s):  
South Africa ◽  
Digestive Tract ◽  
Standard Length ◽  
Feeding Habits ◽  
Clarias Gariepinus ◽  
Male And Female ◽  
Mean Intensity ◽  
Gill Nets ◽  
Larval Stages ◽  
Vaal Dam

Cestodes are parasitic flatworms that live in the digestive tract of vertebrates as adults and often in the liver, muscle, haemocoel, mesentery and brain of various animals as larval stages. To identify the cestodes infecting Clarias gariepinus Burchell, 1822 (sharptooth catfish) in the Vaal Dam, a total of 45 host specimens were collected with the aid of gill nets between October 2011, January and April 2012. The fish were sacrificed and examined for cestode parasites. Two adult cestodes, Tetracampos ciliotheca Wedl, 1861 (prevalence 86.7%, mean intensity = 15, n = 45) and Proteocephalus glanduligerus (Janicki, 1928) (prevalence 51.1%, mean intensity = 5, n = 45) were found in the intestines of the catfish. Both T. ciliotheca and P. glanduligerus are new locality records. There were statistically insignificant differences in the infection of the male and female C. gariepinu. Fish with standard length ranging from 40 cm – 54 cm (≥ 3 years) had the highest prevalence and mean intensity while those ranging from 10 cm – 24 cm (< 1 year) had the lowest prevalence and mean intensity for both cestodes. The study highlights the importance of changing feeding habits of C. gariepinus with age on the prevalence and mean intensity of the two gastrointestinal cestode parasites.

scholarly journals A size threshold governs Caenorhabditis elegans developmental progression

2015 ◽  
Vol 282 (1813) ◽  
pp. 20151283 ◽  
Author(s):  
Sravanti Uppaluri ◽  
Clifford P. Brangwynne
Keyword(s):  
Caenorhabditis Elegans ◽  
Food Availability ◽  
Developmental Stages ◽  
Size Control ◽  
Threshold Size ◽  
Larval Stages ◽  
Developmental Progression ◽  
Order Of Magnitude ◽  
Size Threshold ◽  
The Impact

The growth of organisms from humans to bacteria is affected by environmental conditions. However, mechanisms governing growth and size control are not well understood, particularly in the context of changes in food availability in developing multicellular organisms. Here, we use a novel microfluidic platform to study the impact of diet on the growth and development of the nematode Caenorhabditis elegans . This device allows us to observe individual worms throughout larval development, quantify their growth as well as pinpoint the moulting transitions marking successive developmental stages. Under conditions of low food availability, worms grow very slowly, but do not moult until they have achieved a threshold size. The time spent in larval stages can be extended by over an order of magnitude, in agreement with a simple threshold size model. Thus, a critical worm size appears to trigger developmental progression, and may contribute to prolonged lifespan under dietary restriction.

VULNERABILITY OF THE FIR CONEWORM, DIORYCTRIAABIETIVORELLA (GROTE) (LEPIDOPTERA: PYRALIDAE), IN DIFFERENT LARVAL STAGES TO THE HD-1 STRAIN OF BACILLUS THURINGIENSIS

1997 ◽  
Vol 129 (1) ◽  
pp. 197-198 ◽  
Author(s):  
Richard Trudel ◽  
Éric Bauce ◽  
Jean Cabana ◽  
Claude Guertin
Keyword(s):  
Bacillus Thuringiensis ◽  
Insect Pest ◽  
Specific Effect ◽  
Young Tree ◽  
Seed Orchards ◽  
Larval Stages ◽  
Dioryctria Abietivorella ◽  
Lepidoptera Pyralidae ◽  
Natural Stands ◽  
The Impact

The fir coneworm, Dioryctria abietivorella (Grote), is a major insect pest in seed orchards across Canada and the adjoining eastern and western United States. Larvae feed principally on cones, but they can also feed on needles and occasionally on the bark of young tree trunks (Hedlin et al. 1980; Ruth 1980; Martineau 1985). The potential for a population of D. abietivorella to build up in seed orchards may be greater than in natural stands (Hedlin et al. 1980; Ruth et al. 1982). The use of entomopathogen in the management of fir coneworm could be an adequate measure to reduce the impact of this insect. Moreover, Bacillus thuringiensis ssp. kurstaki has a specific effect on Lepidoptera (Aronson et al. 1986; Gill et al. 1992). The purpose of our study was to determine the activity of the HD-1 strain of B. thuringiensis ssp. kurstaki (serotype H-3a:3b) to larvae D. abietivorella. Bioassays were conducted with first-, third-, and fifth-instar larvae of fir coneworm to determine whether or not the insect's vulnerability to B. thuringiensis varies with larval age.

scholarly journals Dynamics and Management of Rising Outbreak Spruce Budworm Populations

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 748 ◽  
Author(s):  
Jacques Régnière ◽  
Barry Cooke ◽  
Ariane Béchard ◽  
Alain Dupont ◽  
Pierre Therrien
Keyword(s):  
Population Growth ◽  
Density Dependence ◽  
Natural Enemies ◽  
Choristoneura Fumiferana ◽  
Regional Scale ◽  
Adult Emergence ◽  
Spruce Budworm ◽  
Migration Activity ◽  
Larval Stages ◽  
The Impact

Management of spruce budworm, Choristoneura fumiferana (Clem.), outbreak spread requires understanding the demographic processes occurring in low, but rising populations. For the first time, detailed observations were made in the early stages of outbreak development. We sampled populations over a three-year period in both treated and untreated populations in the Lower St-Lawrence region of Quebec, Canada, and measured the density-dependence of survival and population growth rates, and the impact of natural enemies and insecticides. Insecticides tested were Bacillus thuringiensis (Berliner 1915) and tebufenozide. We recorded strong density-dependence of survival between early larval stages and adult emergence, explained largely by the variation of natural enemy impacts and overcrowding. We also observed inverse density-dependence of apparent fecundity: net immigration into lower-density populations and net emigration from the higher, linked to a threshold of ~25% defoliation. Because of high migration rates, none of the 2013 treatments reduced egg populations at the end of summer. However lower migration activity in 2014 allowed population growth to be reduced in treated plots. This evidence lends support to the conclusion that, for a budworm population to increase to outbreak density, it must be elevated via external perturbations, such as immigration, above a threshold density of ~4 larvae per branch tip (L4). Once a population has increased beyond this threshold, it can continue growing and itself become a source of further spread by moth migration. These findings imply that populations can be brought down by insecticide applications to a density where mortality from natural enemies can keep the reduced population in check, barring subsequent immigration. While we recognize that other factors may occasionally cause a population to exceed the Allee threshold and reach outbreak level, the preponderance of immigration implies that if all potential sources of significant numbers of moths are reduced on a regional scale by insecticide applications, a widespread outbreak can be prevented, stopped or slowed down by reducing the supply of migrating moths.

scholarly journals Vertical Transmission

2020 ◽  
Vol 41 (1) ◽  
pp. 2
Author(s):  
Dena Lyras
Keyword(s):  
Public Health ◽  
Infectious Disease ◽  
Vertical Transmission ◽  
Racial Groups ◽  
The Novel ◽  
Local Part ◽  
Rapid Dissemination ◽  
Novel Coronavirus ◽  
The Impact

As we begin 2020, Microbiology is dominating the news with the emergence and rapid dissemination of the novel coronavirus COVID-19. The impact of COVID-19 on public health, with significant financial, logistical and social repercussions, has quickly become apparent. As microbiologists we have an important role to play during this time because we can use our knowledge, expertise and experience to educate the community around us, and to reduce the panic that results from fear and misinformation. It is also critical that we ensure that racial groups are not stigmatised because of an infectious disease. A co-ordinated global effort is required to tackle this new infectious threat, and we are an important local part of this effort. It is also important to develop strategies that can be deployed when the next threat emerges, as it surely will.

Citizen Science Uncovers Phytophthora ramorum as a Threat to Several Rare or Endangered California Manzanita Species

Plant Disease ◽  
2020 ◽  
Vol 104 (12) ◽  
pp. 3173-3182
Author(s):  
Matteo Garbelotto ◽  
Tina Popenuck ◽  
Brett Hall ◽  
Wolfgang Schweigkofler ◽  
Francesco Dovana ◽  
...  
Keyword(s):  
Phytophthora Ramorum ◽  
Sudden Oak Death ◽  
Santa Cruz ◽  
Forest Disease ◽  
Marin County ◽  
Interspecific Differences ◽  
Detached Leaves ◽  
Comparative Susceptibility ◽  
The University ◽  
First Time

The Sudden Oak Death (SOD) Blitzes consist of yearly surveys led by citizen scientists designed to map the distribution of Phytophthora ramorum, cause of the forest disease called SOD, across northern California. During the 2017 Santa Cruz County SOD Blitz, six rare or endangered Arctostaphylos (manzanita) species were found to be possibly symptomatic for the first time. Symptoms included branch cankers and associated canopy mortality, and affected multiple individuals per species. Isolates of P. ramorum were obtained from each of the six species and, through a 30-day-long inoculation experiment on live plants, Koch’s postulates were completed for each one of them, conclusively determining that they all are hosts of this pathogen. Two additional manzanita species were later found to be apparently symptomatic in Marin County. Inoculations on detached branches using an isolate of P. ramorum obtained from one of the six rare species from Santa Cruz County were successful, suggesting that these two species may also be hosts of P. ramorum. Detached leaves of all eight species were also successfully inoculated at the University of California-Berkeley in fall 2018 and then again in spring 2019. In these cases, the same isolate was used for all inoculations, in order to obtain information on the comparative susceptibility of the eight species in question. Both branch and leaf inoculations identified significant interspecific differences in susceptibility. The production of sporangia was low on all species but it was not zero, suggesting that sporulation may cause within-plant and limited across-plant contagion, especially in rainy years.

Formation of the gut in the first two naupliar stages of Acartia clausi and Hemidiaptomus roubaui (Copepoda, Calanoida): comparative structural and ultrastructural aspects

2002 ◽  
Vol 80 (2) ◽  
pp. 232-244 ◽  
Author(s):  
A Baud ◽  
R -M Barthélémy ◽  
S Nival ◽  
M Brunet
Keyword(s):  
Epithelial Cells ◽  
Digestive Tract ◽  
Digestive System ◽  
Larval Stages ◽  
Acartia Clausi ◽  
The Future ◽  
Endodermal Cells ◽  
Structure And Ultrastructure

In this study, the structure and ultrastructure of the digestive system are compared in the early larval stages (nauplii I and II) of two copepod calanoid species, Acartia clausi Giesbrecht, 1889 and Hemidiaptomus roubaui Richard, 1888. The nauplii I of both species have no functional digestive tract, which is represented initially only by a blind esophageal slit and yolky endodermal cells, which fill the most part of the naupliar body, whereas at the nauplius II stage the differentiated digestive tract becomes functional. The resorption cavity corresponding to the future midgut is progressively formed in the endodermal mass during the premolt phase; it is surrounded by differentiating epithelial cells. In the ecdysial phase the foregut has associated labral glands, the midgut young R-, B-, and R'-cells of epithelium, and there is a short open hindgut.

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