Horizontal Transmission in Fungal Populations

2020 ◽  
pp. 337-348
Author(s):  
Rolf F. Hoekstra
Keyword(s):  
Horizontal Transmission ◽  
Fungal Populations

scholarly journals Genetic Diversity of the Symbiotic Fungus Epichloë festucae in Naturally Occurring Host Grass Populations

2021 ◽  
Vol 12 ◽  
Author(s):  
Maria von Cräutlein ◽  
Marjo Helander ◽  
Helena Korpelainen ◽  
Päivi Helena Leinonen ◽  
Beatriz R. Vázquez de Aldana ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Horizontal Transmission ◽  
Gene Clusters ◽  
Host Population ◽  
Selection Pressures ◽  
Symbiotic Fungus ◽  
Red Fescue ◽  
Local Selection ◽  
Survival And Reproduction ◽  
Fungal Populations

Epichloë festucae is a common symbiont of the perennial and widely distributed cool season grass, Festuca rubra. The symbiosis is highly integrated involving systemic growth of the fungus throughout above-ground host parts and vertical transmission from plant to its offspring via host seeds. However, the nature of symbiosis is labile ranging from antagonistic to mutualistic depending on prevailing selection pressures. Both the loss of fungus in the maternal host lineage and horizontal transmission through sexual spores within the host population may partly explain the detected variation in symbiosis in wild grass populations. Epichloë species are commonly considered as pathogens when they produce sexual spores and partly castrate their host plant. This is the pathogenic end of the continuum from antagonistic to mutualistic interactions. Here we examined the population genetic structure of E. festucae to reveal the gene flow, importance of reproduction modes, and alkaloid potential of the symbiotic fungus in Europe. Epichloë-species are highly dependent on the host in survival and reproduction whilst benefits to the host are largely linked to defensive mutualism attributable to fungal-origin bioactive alkaloids that negatively affect vertebrate and/or invertebrate herbivores. We detected decreased genetic diversity in previously glaciated areas compared to non-glaciated regions during the last glacial maximum period and found three major genetic clusters in E. festucae populations: southern, northeastern and northwestern Europe. Sexual reproduction may have a higher role than expected in Spanish E. festucae populations due to the predominance of unique genotypes and presence of both mating types in the region. In contrast, asexual reproduction via host seeds predominates in the Faroe Island and Finland in northern Europe due to the presence of biased mating-type ratios and large dominant genotypes in the E. festucae populations within the region. A substantially larger variation of alkaloid genotypes was observed in the fungal populations than expected, although the variability of the alkaloid genotypes within populations is considerably lower in northern than Spanish populations in southern Europe. E. festucae populations consist of different combinations of alkaloid classes from the gene clusters of ergot alkaloid and indole-terpenes, and from pyrrolopyrazine alkaloid gene. We suggest that the postglacial distribution history of the host grass, prevailing reproduction strategies of E. festucae, and local selection pressures likely explain a large part of the genetic variation observed in fungal populations among geographic regions. The identified alkaloid genotypes can be used by turfgrass breeders to improve resistance against herbivores in red fescue varieties and to develop new sustainable cultivars in Europe.

Horizontal transmission of murine retroviruses.

1987 ◽  
Vol 61 (4) ◽  
pp. 1037-1044 ◽  
Author(s):  
J L Portis ◽  
F J McAtee ◽  
S F Hayes
Keyword(s):  
Horizontal Transmission

scholarly journals Routes for salmonella contamination of poultry meat: epidemiological study from hatchery to slaughterhouse

2002 ◽  
Vol 129 (2) ◽  
pp. 253-265 ◽  
Author(s):  
M. HEYNDRICKX ◽  
D. VANDEKERCHOVE ◽  
L. HERMAN ◽  
I. ROLLIER ◽  
K. GRIJSPEERDT ◽  
...  
Keyword(s):  
Horizontal Transmission ◽  
Poultry Meat ◽  
Contamination Level ◽  
Solid Agar ◽  
Determining Factors ◽  
Production Stages ◽  
Animal Material ◽  
Semi Solid ◽  
Therapeutic Doses ◽  
Broiler House

Data were collected on the prevalence of salmonella at different stages during the life cycle of 18 broiler flocks on different farms as well as during slaughter in different poultry slaughterhouses. For the isolation of salmonella, the highest sensitivity (93.9%) was obtained by enrichment in the semi-solid agar Diasalm. The ‘overshoe method’ utilizing several pairs of overshoes provided the highest sensitivity for determining the salmonella status of the broilers during rearing. A clear decrease of the relative importance of the first production stages was demonstrated for the salmonella contamination of the end product, whereas horizontal transmission of salmonella to broilers during rearing and to broiler carcasses in the slaughterhouse was shown to be the main determinative factor. Ten of the 18 flocks received a salmonella positive status with the highest shedding occurring during the first 2 weeks of rearing. The shedding of the animals was significantly negatively influenced by the use of subtherapeutic or therapeutic doses of antibiotics. The intake of portable material in the broiler house was identified as the most important risk factor for horizontal transmission. Significant associations were found between the contamination level of a flock and hygiene of the broiler house, feed and water in the broiler house and both animal and non-animal material sampled in the environment. No correlation was found between contamination during the rearing period and contamination found after slaughtering. The presence of faecal material in the transport crates and predominantly the identity of the slaughterhouse seemed to be the determining factors for carcass quality. Improved hygiene management during transport of broilers and in some slaughterhouses could significantly reduce the risk of salmonella contamination of poultry meat.

EFFECT OF SEED DIFFUSATES ON FUNGAL POPULATION AND GERMINATION OF SUNFLOWER SEEDS / EFECTO DE EXTRACTOS DE SEMILLAS SOBRE LA POBLACION DE HONGOS Y LA GERMINACION DE SEMILLAS DEL GIRASOL / EFFET DES EXTRAITS DE SEMENCE SUR LA POPULATION DE CHAMPIGNONS ET SUR LA GERMINATION DES GRAINES DE TOURNESOL

Helia ◽  
2001 ◽  
Vol 24 (34) ◽  
pp. 77-82 ◽  
Author(s):  
Rauf Bhutta ◽  
M.H. Rahber Bhatti ◽  
Ahmad Iftikhar
Keyword(s):  
Seed Germination ◽  
Capsicum Annuum ◽  
Alternaria Alternata ◽  
Fusarium Moniliforme ◽  
Macrophomina Phaseolina ◽  
Chemical Pollution ◽  
Sunflower Seeds ◽  
Fungal Population ◽  
Fungal Populations ◽  
Safe Control

SUMMARYAll four seed diffusates used for treatment of sunflower seeds, Azadirachtaindica, Capsicum annuum, Coriandrum sativum and Eugenia jambulana, reduced the populations of seed-borne fungi: Alternaria alternata, Drechslera tetramera, Emericellopsis terricola, Fusarium moniliforme, F.semitectum, Macrophomina phaseolina and Phoma oleracea. Of four seed diffusates, those from A.indica and C.sativum controlled the fungal populations almost 100%. Seed germination was increased in seed samples of both sunflower cultivars under study, HO-1 and NK-212. The obtained results indicate that seed diffusates could substitute costly chemicals for safe control of seed-borne diseases, protecting at the same time the environment from chemical pollution.

scholarly journals Spiroplasma Infection among Ixodid Ticks Exhibits Species Dependence and Suggests a Vertical Pattern of Transmission

2021 ◽  
Vol 9 (2) ◽  
pp. 333
Author(s):  
Shohei Ogata ◽  
Wessam Mohamed Ahmed Mohamed ◽  
Kodai Kusakisako ◽  
May June Thu ◽  
Yongjin Qiu ◽  
...  
Keyword(s):  
16S Rdna ◽  
Tick Species ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Horizontal Transmission ◽  
Ixodid Ticks ◽  
Infection Rates ◽  
Transmission Cycle ◽  
Frequent Event ◽  
Pcr Targeting

Members of the genus Spiroplasma are Gram-positive bacteria without cell walls. Some Spiroplasma species can cause disease in arthropods such as bees, whereas others provide their host with resistance to pathogens. Ticks also harbour Spiroplasma, but their role has not been elucidated yet. Here, the infection status and genetic diversity of Spiroplasma in ticks were investigated using samples collected from different geographic regions in Japan. A total of 712 ticks were tested for Spiroplasma infection by PCR targeting 16S rDNA, and Spiroplasma species were genetically characterized based on 16S rDNA, ITS, dnaA, and rpoB gene sequences. A total of 109 samples originating from eight tick species were positive for Spiroplasma infection, with infection rates ranging from 0% to 84% depending on the species. A linear mixed model indicated that tick species was the primary factor associated with Spiroplasma infection. Moreover, certain Spiroplasma alleles that are highly adapted to specific tick species may explain the high infection rates in Ixodes ovatus and Haemaphysalis kitaokai. A comparison of the alleles obtained suggests that horizontal transmission between tick species may not be a frequent event. These findings provide clues to understand the transmission cycle of Spiroplasma species in wild tick populations and their roles in host ticks.

scholarly journals Newborns at risk of Covid-19 ― lessons from the last year

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Malika D. Shah ◽  
Ola Didrik Saugstad
Keyword(s):  
Horizontal Transmission ◽  
Mode Of Delivery ◽  
Newborn Infants ◽  
World Health ◽  
Premature Delivery ◽  
Mortality And Morbidity ◽  
Skin Contact ◽  
Cord Clamping ◽  
Increased Risk ◽  
Health Organization

Abstract After more than 1 year of the SARS-CoV-2 pandemic, a great deal of knowledge on how this virus affects pregnant women, the fetus and the newborn has accumulated. The gap between different guidelines how to handle newborn infants during this pandemic has been minimized, and the American Academy of Pediatrics (AAP)’s recommendations are now more in accordance with those of the World Health Organization (WHO). In this article we summarize present knowledge regarding transmission from mother to the fetus/newborn. Although both vertical and horizontal transmission are rare, SARS-CoV-2 positivity is associated with an increased risk of premature delivery and higher neonatal mortality and morbidity. Mode of delivery and cord clamping routines should not be affected by the mother’s SARS-CoV-2 status. Skin to skin contact, rooming in and breastfeeding are recommended with necessary hygiene precautions. Antibodies of infected or vaccinated women seem to cross both the placenta and into breast milk and likely provide protection for the newborn.

scholarly journals Experimental Horizontal Transmission of Enterospora nucleophila (Microsporea: Enterocytozoonidae) in Gilthead Sea Bream (Sparus aurata)

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 362
Author(s):  
Amparo Picard-Sánchez ◽  
M. Carla Piazzon ◽  
Itziar Estensoro ◽  
Raquel Del Pozo ◽  
Nahla Hossameldin Ahmed ◽  
...  
Keyword(s):  
Sparus Aurata ◽  
Horizontal Transmission ◽  
Infected Fish ◽  
Gilthead Sea Bream ◽  
Sea Bream ◽  
Target Tissue ◽  
Farmed Fish ◽  
Infection Level ◽  
Available Information

Enterospora nucleophila is a microsporidian enteroparasite that infects mainly the intestine of gilthead sea bream (Sparus aurata), leading to an emaciative syndrome. Thus far, the only available information about this infection comes from natural outbreaks in farmed fish. The aim of the present study was to determine whether E. nucleophila could be transmitted horizontally using naturally infected fish as donors, and to establish an experimental in vivo procedure to study this host–parasite model without depending on natural infections. Naïve fish were exposed to the infection by cohabitation, effluent, or intubated either orally or anally with intestinal scrapings of donor fish in four different trials. We succeeded in detecting parasite in naïve fish in all the challenges, but the infection level and the disease signs were always milder than in donor fish. The parasite was found in peripheral blood of naïve fish at 4 weeks post-challenge (wpc) in oral and effluent routes, and up to 12 wpc in the anal transmission trial. Molecular diagnosis detected E. nucleophila in other organs besides intestine, such as gills, liver, stomach or heart, although the intensity was not as high as in the target tissue. The infection tended to disappear through time in all the challenge routes assayed, except in the anal infection route.

scholarly journals Improving Contagion and Horizontal Transmission of Entomopathogenic Fungi by the White-Spotted Longicorn Beetle, Anoplophora malasiaca, with Help of Contact Sex Pheromone

Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 383
Author(s):  
Nao Fujiwara-Tsujii ◽  
Hiroe Yasui
Keyword(s):  
Sex Pheromone ◽  
Entomopathogenic Fungi ◽  
Horizontal Transmission ◽  
Pathogenic Fungi ◽  
Male Mating ◽  
Contact Sex Pheromone ◽  
Beauveria Brongniartii ◽  
Contact Pheromone ◽  
Horticultural Crops ◽  
Longicorn Beetle

The white-spotted longicorn beetle, Anoplophora malasiaca, is one of the most destructive pests of horticultural crops and street trees. Effective controls are needed because the effect of marketed insecticides is limited. Entomopathogenic fungi offer a solution, and improving the rate of infection would be a breakthrough in this beetle’s control. The combination of pathogenic fungi and the beetle’s contact sex pheromone was suggested. The surface of the female body is covered with contact sex pheromone, which elicit male mating behavior. To develop a method for the practical control of this beetle, we evaluated the arrestant activity of female extract containing contact pheromone coated on a black glass model. Males presented with a coated model held on for 5 h (mean) during an 8-h experiment. In contrast, males presented with a control model held on for <0.3 h. Males that held onto coated models attached to fabric impregnated with conidia of the fungus Beauveria brongniartii picked up much conidia, which they then passed on to females during mating.

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