Effect of the mycotoxins penitrem, paxilline and lolitrem B on the electromyographic activity of skeletal and gastrointestinal smooth muscle of sheep

Smith, Barry L.; McLeay, L. M.; Embling, P. P.

doi:10.1016/s0034-5288(97)90130-2

Cited by 34 publications

(26 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Some groups of alkaloids have been identified as harmful, for example ergopeptine (ergovaline) and isoprenoid lolitrem (lolitrem B) which cause fescue toxicosis and ryegrass staggers, respectively (Smith et al, 1997). The effects of the different beneficial and harmful groups will be discussed in more detail in the section “Endophyte as a control method.” These bioactive properties have driven research on the alkaloids produced by endophytic fungi because of the services they provide to their host plant and agricultural systems (Table 1).…”

Section: Fungal Endophytesmentioning

confidence: 99%

A Review of Perennial Ryegrass Endophytes and Their Potential Use in the Management of African Black Beetle in Perennial Grazing Systems in Australia

et al. 2017

View full text Add to dashboard Cite

The major insect pest of Australian cool temperate pastures is the root-feeding insect Heteronychus arator (African black beetle, ABB). Significant pasture damage can occur even at low ABB densities (11 individuals per square meter), and often re-sowing of the whole paddock is required. Mitigation of the effects of pasture pests, and in particular subterranean species such as the larval form of ABB, can be challenging. Early detection is limited by the ability to visualize above-ground symptoms, and chemical control of insects in soil is often ineffective. This review takes a look at the historical events that molded the pastoral landscape in Australia. The importation route, changes in land management and pasture composition by European settlers may have aided the establishment of ABB in Australia. Perennial ryegrass Lolium perenne is discussed as it is one of the most important perennial agricultural grasses and is widely-sown in moderate-to-high-rainfall temperate zones of the world. Endophytic fungi from the genus Epichloë form symbiotic relationships with cool season grasses such as Lolium perenne (perennial ryegrass). They have been studied extensively and are well documented for enhancing persistence in pasture via a suite of bioactive secondary metabolites produced by the fungal symbionts. Several well-characterized secondary metabolites are discussed. Some can have negative effects on cattle (e.g., ergovaline and lolitrems) while others have been shown to benefit the host plant through deterrence of insect pests from feeding and by insecticidal activity (e.g., peramine, lolines, ergopeptines). Various control methods for ABB are also discussed, with a focus on the potential role of asexual Epichloë endophytes.

show abstract

Section: Fungal Endophytesmentioning

confidence: 99%

A Review of Perennial Ryegrass Endophytes and Their Potential Use in the Management of African Black Beetle in Perennial Grazing Systems in Australia

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Typical clinical symptoms are muscle fasciculation, tremor, and ataxia, which might even progress into tonic convulsions. As probable mechanisms of action, the impairment of the GABAergic pathways (Smith et al 1997;Wang et al 2003), was recently challenged by the finding that lolitrem has a potent effect on potassium channel conductance (Dalziel et al 2005). Neothyphodium lolii produces not only tremorgenic toxins, but also peramine, which exerts a potent repellent effect that protects infected plants from insect plagues and earthworm damage, exemplifying the unique symbiosis between endophytes and their hosts.…”

Section: Clinical Mycotoxicoses In Dairy Cowsmentioning

confidence: 99%

Mycotoxins in cattle feeds and carry-over to dairy milk: A review

Fink‐Gremmels

2008

Food Additives & Contaminants: Part A

309

260

View full text Add to dashboard Cite

The complex diet of ruminants, consisting of forages, concentrates, and preserved feeds, can be a source of very diverse mycotoxins that contaminate individual feed components. A number of mycotoxins are successfully inactivated by the rumen flora, whereas others pass unchanged or are converted into metabolites that retain biological activity. Hence, the barrier function of the rumen largely determines the susceptibility of dairy cows and other ruminant species towards individual mycotoxins. An impairment of this barrier function due to diseases or the direct antimicrobial effect of certain mycotoxins may increase absorption rates. The rate of absorption determines not only the internal dose and risk for adverse health effects, but also the excretion of mycotoxins and the biologically active metabolites into milk.

show abstract

“…This is a condition in which animals grazing on endophyte-infected pastures develop ataxia, tremors and sensitivity to external stimuli. The reaction to lolitrem is long-lasting, but is completely reversible (Smith et al 1997;McLeay et al 1999). The mechanism by which lolitrem B and related indole-diterpenes cause tremors in mammals is not well defined, but biochemical and clinical studies indicate that these effects are due in part to actions on receptors and interference with neurotransmitter release in the central and peripheral nervous systems (Selala et al 1991).…”

Section: Introductionmentioning

confidence: 99%

Molecular cloning and genetic analysis of a symbiosis-expressed gene cluster for lolitrem biosynthesis from a mutualistic endophyte of perennial ryegrass

et al. 2005

View full text Add to dashboard Cite

Lolitrems are potent tremorgenic mycotoxins that are synthesised by clavicipitaceous fungal endophytes of the Epichloë/Neotyphodium group in association with grasses. These indole-diterpenes confer major ecological benefits on the grass-endophyte symbiotum. A molecular signature for diterpene biosynthesis is the presence of two geranylgeranyl diphosphate (GGPP) synthases. Using degenerate primers for conserved domains of fungal GGPP synthases, we cloned two such genes, ltmG and ggsA, from Neotyphodium lolii. Adjacent to ltmG are two genes, ltmM and ltmK, that are predicted to encode an FAD-dependent monooxygenase and a cytochrome P450 monooxygenase, respectively. The cluster of ltm genes is flanked by AT-rich retrotransposon DNA that appears to have undergone extensive repeat induced point (RIP) mutation. Epichloë festucae, the sexual ancestor of N. lolii, contains an identical ltm gene cluster, but lacks the retrotransposon "platform'' on the right flank. Associations established between perennial ryegrass and an E. festucae mutant deleted for ltmM lack detectable levels of lolitrems. A wild-type copy of ltmM complemented this phenotype, as did paxM from Penicillium paxilli. Northern hybridization and RT-PCR analysis showed that all three genes are weakly expressed in culture but strongly induced in planta. The relative endophyte biomass in these associations was estimated by real-time PCR to be between 0.3 and 1.9%. Taking this difference into account, the steady-state levels of the ltm transcripts are about 100-fold greater than the levels of the endogenous ryegrass beta-tubulin (beta -Tub1) and actin (Act1) RNAs. Based on these results we propose that ltmG, ltmM and ltmK are members of a set of genes required for lolitrem biosynthesis in E. festucae and N. lolii.

show abstract

Effect of the mycotoxins penitrem, paxilline and lolitrem B on the electromyographic activity of skeletal and gastrointestinal smooth muscle of sheep

Cited by 34 publications

References 13 publications

A Review of Perennial Ryegrass Endophytes and Their Potential Use in the Management of African Black Beetle in Perennial Grazing Systems in Australia

A Review of Perennial Ryegrass Endophytes and Their Potential Use in the Management of African Black Beetle in Perennial Grazing Systems in Australia

Mycotoxins in cattle feeds and carry-over to dairy milk: A review

Molecular cloning and genetic analysis of a symbiosis-expressed gene cluster for lolitrem biosynthesis from a mutualistic endophyte of perennial ryegrass

Contact Info

Product

Resources

About