<Emphasis Type="Italic">Trichoderma harzianum</Emphasis>: occurrence in the air and clinical significance

Trichoderma harzianum, a filamentous fungus, is being widely used as a potential biopesticide. The potential of this fungus in causing skin sensitization, however, was poorly investigated as yet. The objective of this study was to monitor the occurrence of T. harzianum in the air and to explore its skin sensitizing potential. Seasonal periodicity of T. harzianum was studied for the years 2002–2004 by an Andersen air sampler. The skin sensitizing potential of T. harzianum extract was studied in 389 patients with suspected respiratory allergy by skin prick test (SPT) and specific IgE level was determined by ELISA. SDS–PAGE and immunoblotting were also performed. T. harzianum colony count varied from 3.69 to 134.88 CFU m⁻³ with the peak achieved in February. Relative humidity was found to be a significant (P < 0.05) factor predicting the occurrence of T. harzianum in the air. Positive skin reaction (wheal diameter ≥ 3 mm) was observed in 105 patients (26.99%). T. harzianum crude extract was resolved in 18 protein bands (12–72 kDa) on SDS–PAGE (12% gel) including two IgE-binding protein bands (21 and 32 kDa). T. harzianum can be considered an important inhalant allergen.     

Phylogenetic and biogeographic implications inferred by mitochondrial intergenic region analyses and ITS1-5.8S-ITS2 of the entomopathogenic fungi <Emphasis Type="Italic">Beauveria bassiana</Emphasis> and <Emphasis Type="Italic">B. brongniartii</Emphasis>

Background  

The entomopathogenic fungi of the genus Beauveria are cosmopolitan with a variety of different insect hosts. The two most important species, B. bassiana and B. brongniartii, have already been used as biological control agents of pests in agriculture and as models for the study of insect host - pathogen interactions. Mitochondrial (mt) genomes, due to their properties to evolve faster than the nuclear DNA, to contain introns and mobile elements and to exhibit extended polymorphisms, are ideal tools to examine genetic diversity within fungal populations and genetically identify a species or a particular isolate. Moreover, mt intergenic region can provide valuable phylogenetic information to study the biogeography of the fungus.     

Control of the bean rust fungus <Emphasis Type="Italic">Uromyces appendiculatus</Emphasis> by means of <Emphasis Type="Italic">Trichoderma harzianum</Emphasis>: leaf disc assays on the antibiotic effect of spore suspensions and culture filtrates

Several species of the fungal genus Trichoderma act as antagonists of other fungi. A number of strains from the Trichoderma species T. harzianum Rifai are used as biological control agents for the control of soilborne as well as foliar plant pathogens. Six T. harzianum strains, five of them isolated from commercial preparations, were evaluated for their capability to control the bean rust fungus Uromyces appendiculatus (Pers. ex Pers.) Unger. Different kinds of leaf disc assays were performed with conidial spore suspensions and sterile culture filtrates of the T. harzianum strains. Great differences were observed concerning the efficacy of the Trichoderma strains to reduce the number of the uredial pustules developing after rust inoculation which followed the application of the particular Trichoderma strains. Efficacy values ranged from 1 to over 50%. Increasing spore or culture filtrate concentrations of the two most effective isolates T12 and T_U led to decreases in the number of developing uredial pustules. Culture filtrate applications had a protective but no curative effect. T12 spore suspensions maintained their disease reducing activity even when autoclaved. This and some other evidence for an antibiotic interaction between T. harzianum and U. appendiculatus are discussed. Handling Editor: Reijo Karjalainen.     

Compatibility of <Emphasis Type="Italic">Piriformospora indica</Emphasis> and <Emphasis Type="Italic">Trichoderma harzianum</Emphasis> as dual inoculants in black pepper (<Emphasis Type="Italic">Piper nigrum</Emphasis> L.)

The compatibility of two biological inoculants, Trichoderma harzianum, a mycoparasitic biological control fungus and Piriformospora indica, a root colonizing plant-growth promoting endophytic fungus was evaluated using tissue cultured black pepper plantlets. We report, for the first time, the ability of P. indica to colonize black pepper, a perennial climber. T. harzianum inhibited the growth of P. indica in an in vitro dual culture plate assay. Simultaneous inoculation with both biological inoculants of tissue cultured black pepper plantlets negatively influenced root colonization by P. indica. However, when P. indica was applied initially followed 30 days later by T. harzianum, there was increased root colonization by the root endophyte P. indica and beneficial effects were found on the growth of the black pepper plants. The present study also showed that the efficacy of inoculation of the two fungal biological agents can be increased by sequential application of P. indica at the hardening stage followed by T. harzianum during transplanting into a soil-sand mixture.     

Screening of white‐rot fungi for bioprocessing of wheat straw into ruminant feed

Aim

In this study, the biological variation for improvement of the nutritive value of wheat straw by 12 Ceriporiopsis subvermispora, 10 Pleurotus eryngii and 10 Lentinula edodes strains was assessed. Screening of the best performing strains within each species was made based on the in vitro degradability of fungal‐treated wheat straw.

Methods and Results

Wheat straw was inoculated with each strain for 7 weeks of solid state fermentation. Weekly samples were evaluated for in vitro gas production (IVGP) in buffered rumen fluid for 72 h. Out of the 32 fungal strains studied, 17 strains showed a significantly higher (P < 0·05) IVGP compared to the control after 7 weeks (227·7 ml g^?1 OM). The three best Ceriporiopsis subvermispora strains showed a mean IVGP of 297·0 ml g^?1 OM, while the three best P. eryngii and L. edodes strains showed a mean IVGP of 257·8 and 291·5 ml g^?1 OM, respectively.

Conclusion

Ceriporiopsis subvermispora strains show an overall high potential to improve the ruminal degradability of wheat straw, followed by L. edodes and P. eryngii strains.

Significance and Impact of the Study

Large variation exists within and among different fungal species in the valorization of wheat straw, which offers opportunities to improve the fungal genotype by breeding.     

Identification and characterization of bovine regulator of telomere length elongation helicase gene (<Emphasis Type="Italic">RTEL</Emphasis>): molecular cloning,expression distribution,splice variants and DNA methylation profile

Background  

The genetic basis of telomere length heterogeneity among mammalian species is still not well understood. Recently, a gene named regulator of telomere length elongation helicase (RTEL) was identified and predicted to be an essential participant in species-specific telomere length regulation in two murine species. To obtain broader insights into its structure and biological functions and to ascertain whether RTEL is also a candidate gene in the regulation of telomere length diversity in other mammalian species, data from other mammals may be helpful.     

Impact of biological control agents on fusaric acid secreted from <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> f. sp. <Emphasis Type="Italic">gladioli</Emphasis> (Massey) Snyder and Hansen in <Emphasis Type="Italic">Gladiolus grandiflorus</Emphasis> corms

Fusaric acid (FA) (5-n-butylpuridine 2-carboxyl acid), a highly toxic secondary metabolite produced by Fusarium oxysporum strains, plays a significant role in disease development. The abilities of three F. oxysporum f. sp. gladioli (Massey) Snyder and Hansen isolates (G010; 649-91; and 160-57) to produce FA in infected Gladiolus corm tissues was evaluated in vitro in relation to the presence of two biological control agents, Trichoderma harzianum T22, and Aneurinobacillus migulanus. Pathogenicity tests were used to differentiate between the abilities of the F. oxysporum strains to secrete FA. FA was identified using LC/MS and quantified using HPLC. Isolate G010 was significantly more virulent (P < 0.01) on Gladiolus grandiflorus corms; it secretes 1.8 μM FA/g fresh weight corm into inoculated Gladiolus. Moreover, G010 was the only isolate that produced FA among the three examined isolates. There was a correlation between the corm lesion area and the FA secretion ability of F. oxysporum f. sp. gladioli (P < 0.001; r ² = 0.96). No FA was detected in PDA cultures of F.oxysporum f. sp. gladioli isolates. The presence of T. harzianum T22 appeared to prevent FA secretion into the corms. In the presence of A. migulanus, however, the amount of FA secreted into the corm tissues increased. These results support the use of T. harzianum as an effective biological control agent against F. oxysporum f. sp. gladioli.     

High throughput detection of <Emphasis Type="Italic">Coxiella burnetii</Emphasis> by real-time PCR with internal control system and automated DNA preparation

Background  

Coxiella burnetii is the causative agent of Q-fever, a widespread zoonosis. Due to its high environmental stability and infectivity it is regarded as a category B biological weapon agent. In domestic animals infection remains either asymptomatic or presents as infertility or abortion. Clinical presentation in humans can range from mild flu-like illness to acute pneumonia and hepatitis. Endocarditis represents the most common form of chronic Q-fever. In humans serology is the gold standard for diagnosis but is inadequate for early case detection. In order to serve as a diagnostic tool in an eventual biological weapon attack or in local epidemics we developed a real-time 5'nuclease based PCR assay with an internal control system. To facilitate high-throughput an automated extraction procedure was evaluated.     

Integration of Pythium nunn and Trichoderma harzianum isolate T-95 for the biological control of Pythium damping-off of cucumber

Two biological control agents, Pythium nunn and Trichoderma harzianum isolate T-95, were combined to reduce Pythium damping-off of cucumber in greenhouse experiments lasting 3–4 weeks. T. harzianum T-95, a rhizosphere competent mutant, was applied to seeds and P. nunn was applied to pasteurized and raw soils naturally and artificially infested with Pythium ultimum. Some treatments were also amended with bean leaves to enhance the activity of P. nunn. The biological control of Pythium damping-off was evaluated in a Colorado soil (Nunn sandy loam) and an Oregon soil mix, which were replanted twice after 2 and 3 months. Interactions between P. nunn and T-95 were detected in the Colorado but not the Oregon soil. No consistent evidence of antagonism between P. nunn and T. harzianum was seen, and significant interactions were detected in the Colorado, but not the Oregon soil. In the first planting of some treatments, the combination of P. nunn and T. harzianum gave greater control of damping-off than either applied alone. P. nunn was most effective in soils that were pasteurized or amended with bean leaves. T. harzianum controlled Pythium damping-off in the Colorado, but not the Oregon soil. In both soils, disease declined over time in treatments amended with bean leaves but without P. nunn or T. harzianum added. This suppression was greater in the Colorado soil, which contained an indigenous population of P. nunn. This work demonstrates that two compatible biological control agents can be combined to give additional control of a soil-borne plant pathogen.     

Specific and sensitive detection of the conifer pathogen <Emphasis Type="Italic">Gremmeniella abietina</Emphasis> by nested PCR

Background  

Gremmeniella abietina (Lagerb.) Morelet is an ascomycete fungus that causes stem canker and shoot dieback in many conifer species. The fungus is widespread and causes severe damage to forest plantations in Europe, North America and Asia. To facilitate early diagnosis and improve measures to control the spread of the disease, rapid, specific and sensitive detection methods for G. abietina in conifer hosts are needed.     

In vivo observation of gold nanoparticles in the central nervous system of <Emphasis Type="Italic">Blaberus discoidalis</Emphasis>

Background  

Nanoparticles (NPs) are widely studied for biomedical applications. Understanding interactions between NPs and biomolecules or cells has yet to be achieved. Here we present a novel in vivo method to study interactions between NPs and the nervous system of the discoid or false dead-head roach, Blaberus discoidalis. The aims of this study were to present a new and effective method to observe NPs in vivo that opens the door to new methods of study to observe the interactions between NPs and biological systems and to present an inexpensive and easy-to-handle biological system.     

Specific PCR assays for the detection of <Emphasis Type="Italic">Trichoderma harzianum</Emphasis> causing green mold disease during mushroom cultivation

We have developed a polymerase chain reaction (PCR)-based detection method for Trichoderma harzianum, which causes green mold disease in mushroom cultivation fields and facilities. Based on the sequence data of the internal transcribed spacer (ITS) region of T. harzianum strains and several other species, six primers consisting of three forward and three reverse primers were designed. Among the nine possible combinations of these primers, PCR with the pair THITS-F2 and THITS-R3 distinguished most T. harzianum strains from other Trichoderma species. The optimal annealing temperature for detection of T. harzianum strains was from 62° to 63°C with this primer combination. We designed new primers derived from THITS-F2 and THITS-R3. Annealing temperatures to detect T. harzianum ranged from 64° to 67°C using the new primers. The detection limit of T. harzianum DNA was 50 fg by nested PCR with THITS-F1 and LR1-1 for the first PCR and the new primers for the second PCR. T. harzianum was readily detectable in contaminated cultures of Lentinula edodes by this method.     

Hormonal induction of gamete release,and in-vitro fertilisation,in the critically endangered Southern Corroboree Frog, <Emphasis Type="Italic">Pseudophryne corroboree</Emphasis>

Background  

Conservation Breeding Programs (CBP's) are playing an important role in the protection of critically endangered anuran amphibians, but for many species recruitment is not successful enough to maintain captive populations, or provide individuals for release. In response, there has been an increasing focus on the use of Assisted Reproductive Technologies (ART), including the administration of reproductive hormones to induce gamete release followed by in vitro fertilisation. The objective of this study was to test the efficacy of two exogenous hormones to induce gamete release, for the purpose of conducting in vitro fertilisation (IVF), in one of Australia's most critically endangered frog species, Pseudophryne corroboree.     

Historical biogeography of the land snail <Emphasis Type="Italic">Cornu aspersum</Emphasis>: a new scenario inferred from haplotype distribution in the Western Mediterranean basin

Background  

Despite its key location between the rest of the continent and Europe, research on the phylogeography of north African species remains very limited compared to European and North American taxa. The Mediterranean land mollusc Cornu aspersum (= Helix aspersa) is part of the few species widely sampled in north Africa for biogeographical analysis. It then provides an excellent biological model to understand phylogeographical patterns across the Mediterranean basin, and to evaluate hypotheses of population differentiation. We investigated here the phylogeography of this land snail to reassess the evolutionary scenario we previously considered for explaining its scattered distribution in the western Mediterranean, and to help to resolve the question of the direction of its range expansion (from north Africa to Europe or vice versa). By analysing simultaneously individuals from 73 sites sampled in its putative native range, the present work provides the first broad-scale screening of mitochondrial variation (cyt b and 16S rRNA genes) of C. aspersum.     

Determination of vertebral heart score in three species of Spider monkey (Ateles fusciceps,A. hybridus and A. paniscus)

Background

The vertebral heart score (VHS) is a method of evaluation of cardiac size well documented in domestic mammals and in other primate species, and the aim of this study was to determine the VHS in three species of Spider monkey.

Methods

In this retrospective study, right lateral radiographs of thirty clinically well animals were reviewed and VHS determined. The species included were Ateles fusciceps (n=17), Ateles hybridus (n=8) and Ateles paniscus (n=5).

Results

The VHS was found to vary between species and was 9.73±0.81 for A. fusciceps, 10.53±0.37 for A. hybridus and 10.45±0.27 for A. paniscus.

Conclusions

The observed values appear consistent with values determined for other primate species. There was statistically significant variation noted between species, and so VHS should be considered species‐specific in this genus. The values determined may be of benefit in objectively evaluating cardiac size in the species investigated.     

Diarrhea-associated biofilm formed by enteroaggregative <Emphasis Type="Italic">Escherichia coli</Emphasis> and aggregative <Emphasis Type="Italic">Citrobacter freundii</Emphasis>: a consortium mediated by putative F pili

Background  

Enteroaggregative Escherichia coli (EAEC) are enteropathogenic strains identified by the aggregative adhesion (AA) pattern that share the capability to form biofilms. Citrobacter freundii is classically considered as an indigenous intestinal species that is sporadically associated with diarrhea.     

Antagonistic Effects of Trichoderma harzianum Isolates against Ceratocystis radicicola: pioneering a Biocontrol Strategy against Black Scorch Disease in Date Palm Trees

Date palm is an important subsistence crop in arid regions due to its ability to grow under adverse environmental conditions such as high temperature, salinity and drought. Nevertheless, ideal conditions for its growth and production are also favourable to fungal diseases such as black scorch disease caused by Ceratocystis radicicola. The aim of this study was to develop a method of biological control through the isolation, identification and examination of the effectiveness of bioagents in controlling black scorch disease. Twenty‐five isolates of Trichoderma spp. were isolated from the rhizosphere of healthy date palm trees and morphological, microscopic and molecular approaches confirmed the identity of 11 isolates as Trichoderma harzianum species complex (THSC). In vivo study, application of both spore suspension and culture filtrates of T. harzianum decreased the size of necroses caused by C. radicicola. Additionally, scanning electron microscopy (SEM) showed lysis of the hyphal pathogen and phialoconidia along with scattered aleurioconidia. Results from the volatile metabolic assay and SEM suggested potential roles of cell wall degradation enzymes and volatile substances produced by T. harzianum as two collective mechanisms leading to degrade the cell wall of the pathogen and inhibit fungal growth. Altogether, results from our study demonstrated the efficacy and utility of using bioagents to control black scorch disease which could improve date palm yield.