Fungi Vectored by the Bark Beetle Ips typographus Following Hibernation Under the Bark of Standing Trees and in the Forest Litter

The bark beetle Ips typographus has different hibernation environments, under the bark of standing trees or in the forest litter, which is likely to affect the beetle-associated fungal flora. We isolated fungi from beetles, standing I. typographus-attacked trees, and forest litter below the attacked trees. Fungal identification was done using cultural and molecular methods. The results of the two methods in detecting fungal species were compared. Fungal communities associated with I. typographus differed considerably depending on the hibernation environment. In addition to seven taxa of known ophiostomoid I. typographus-associated fungi, we detected 18 ascomycetes and anamorphic fungi, five wood-decaying basidomycetes, 11 yeasts, and four zygomycetes. Of those, 14 fungal taxa were detected exclusively from beetles that hibernated under bark, and six taxa were detected exclusively from beetles hibernating in forest litter. The spruce pathogen, Ceratocystis polonica, was detected occasionally in bark, while another spruce pathogen, Grosmannia europhioides, was detected more often from beetles hibernating under the bark as compared to litter. The identification method had a significant impact on which taxa were detected. Rapidly growing fungal taxa, e.g. Penicillium, Trichoderma, and Ophiostoma, dominated pure culture isolations; while yeasts dominated the communities detected using molecular methods. The study also demonstrated low frequencies of tree pathogenic fungi carried by I. typographus during its outbreaks and that the beetle does not require them to successfully attack and kill trees.     

Gut-associated yeast in bark beetles of the genus Dendroctonus Erichson (Coleoptera: Curculionidae: Scolytinae)

Scolytine bark beetles are the most destructive pests of conifers; they sometimes aggregate in such large numbers that they actually kill their hosts. They maintain close relationships with yeasts and fungi, in particular those that are assumed to aid in digestive, detoxification processes and pheromone production. In this study, 403 yeast strains were isolated from the guts, ovaries, eggs and frass of nine bark beetle species in the genus Dendroctonus Erichson. The beetles were collected from 10 conifer species at 34 locations in Mexico, Guatemala and the USA. Yeast identification was based on partial DNA sequences from 18S rDNA, 26S rDNA and internal transcribed spacer (ITS1), as well as morphological and physiological characteristics. A combined phylogenetic analysis delimited 11 clades with sequences similar to Candida arabinofermentans , C. ernobii , C. membranifaciens (including C. lessepsii , Pichia mexicana and P. scolyti ), C. oregonensis , C. piceae , Kuraishia capsulata (including K. capsulata and K. cf. molischiana ), Pichia americana , P. canadensis , P. glucozyma , P. guilliermondii and an undescribed species of Candida . Nucleotide divergences between the major clades were at least 5% while, with the exception of 30 isolates, yeasts within clades differed from named reference species at fewer than 1% of the nucleotide sites. There do not appear to be obligate relationships between particular yeasts and specific anatomical partitions, nor between particular yeasts and bark beetle species. Some yeasts do appear to be preferentially associated with bark beetles feeding on different conifer genera and therefore host plant defences may limit yeast community diversity in Dendroctonus .  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 325–342.     

Studies on Baker's yeasts of East Pakistan II

Summary 88 strains of yeast and 4 strains of fungi imperfecti have been isolated from dough from three more districts of East Pakistan. The yeasts comprise 53 strains ofSaccharomyces carlsbergensis, 15 strains ofCandida krusei, 8 strains ofCandida guilliermondii var.membranaefaciens, 6 strains ofTorulopsis colliculosa, 2 strains ofTorulopsis globosa, and 4 strains ofHansenula anomala. Of the four strains of fungi imperfecti, 3 belonged toCladosporium butyri and one toSporophora sp. TheSporophora sp. is considered to be a contaminant.The 92 isolates have been tested for their capacity to ferment -methyl glucoside. The possibility of the utilisation of the fermentation of -methyl glucoside as an additional character in yeast taxonomy has been discussed.Tests for the syntheses of various members of vitamin B-complex have shown that all the 92 isolates are more or less autotrophic.     

Behavior of male and female spruce bark beetles,Ips typographus,on the bark of host trees during mass attack

The behavior of 118 spruce bark beetles, Ips typographus,was observed on trees under colonization. Most individuals were followed from when they landed until they entered or left the tree. Both males and females spent most time inspecting crevices and searching for a place to start boring or for a hole to enter. These behaviors accounted for 87 and 70% of all behavioral acts recorded for males and females, respectively. Females entered galleries with males only after a period of pushing at the gallery entrance. Males spent on average 3 min and females 4 min on the bark before entering or leaving the tree. Thirty-three percent of the beetles eventually entered the tree, 31% flew away, 35% dropped from the host, and one beetle was eaten by a predator. The results are discussed in relation to the question of mate choice in bark beetles and to studies on attack dynamics of spruce bark beetle populations.     

Four new yeasts in the Candida mesenterica clade associated with basidiocarp-feeding beetles

We isolated five yeasts related to Candida mesenterica from the digestive tract, frass, and habitat of beetles in six families inhabiting basidiocarps. Based on rDNA sequence comparisons and phenotypic characters, the yeasts were identified as Kodamaea ohmeri and four undescribed taxa. Phylogenetic analysis of combined small and large subunit ribosomal DNA sequences placed the five taxa in a statistically well supported clade with C. mesenterica, Candida suecica and other yeast species known from basidiocarps, including 'Endomyces scopularum' (CBS154.92 and 155.92), Candida fukazawae, Candida fungicola and Candida sagamina. Only one of the new taxa produced ascospores; the other three reproduced only asexually. The yeasts appear to be less closely associated with beetles than with the beetle habitat. The new species and their type strains are Kodamaea laetipori (type strain NRRL Y-27713 T), Candida derodonti (type strain NRRL Y-2771 1 T), Candida arcana (type strain NRRL Y-27712 T) and Candida plutei (type strain NRRL Y-27715 T).     

Microbial assimilation of alkyl nitro compounds and formation of nitrite

66 representative strains of bacteria, yeasts and fungi were tested for their ability to grow in a semidefined medium containing 0.5% nitroethane as a nitrogen source. About half of them were found capable of growing in the medium. Hansenula beijerinckii, Candida utilis, and Penicillium chrysogenum were most active in assimilating nitroethane. 2-Nitropropane inhibited growth of most of the microorganisms tested in a medium containing 0.2% peptone and 0.2% glycerol. Hansenula mrakii was found to grow rapidly in the nitroethane-peptone medium after a lag phase. Nitrite was accumulated in the culture fluid after the phase of logarithmic multiplication, and increased with increase of the growth, followed by a decline after the maximum growth. The alkyl nitro compounds were oxidatively denitrified to form nitrite by the crude enzyme from Hansenula mrakii. Nitroethane was generally a poor substrate, but was the best inducer to produce the nitro compounds oxidizing enzyme. 2-Nitropropane and nitroethane were enzymatically oxidized to and acetone and acetaldehyde, respectively, which were isolated as 2,4-dinitrophenylhydrazones and identified. Nitrite formed was found to be reduced into ammonia by the intact cells and also the crude enzyme.     

Identification and characterization of yeasts in brem, a traditional Balinese rice wine

Fifty-one yeast strains isolated from fermented mash of Balinese rice wine, brem, fermented using five different types of starters, ragi tape, were identified on the basis of their internal transcribed spacer (ITS) regions and their 18S rDNA sequences. The results revealed that Saccharomyces cerevisiae(35 strains), Candida glabrata(six strains), Pichia anomala(three strains) and Issatchenkia orientalis(seven strains) were the main yeasts in the fermentation of the rice wine. These yeasts undergo succession during the fermentation in which S. cerevisiae was mostly found as the principal yeast at the end of fermentation. Phylogenetic analysis based on the 18S rDNA sequences of selected strains placed the isolated S. cerevisiae strains in the Saccharomyces sensu stricto group. Karyotype analysis of the S. cerevisiae strains resolved using pulsed field gel electrophoresis (PFGE) showed that the strains are typically associated with different types of starters.     

Emergence patterns of univoltine and bivoltine Ips typographus (L.) populations and associated natural enemies

Control measures aiming at reducing bark beetle populations and preserving their natural enemies require a sound knowledge on their overwintering and emergence behaviour. These behavioural traits were investigated in univoltine and bivoltine populations of the European spruce bark beetle (Ips typographus [L.], Coleoptera: Scolytinae) and its predators and parasitoids over several consecutive years. In univoltine populations, roughly 50% of the bark beetles left their brood trees in fall together with most parasitoids and some significant predatory flies and beetles. In bivoltine populations, <10% of the second bark beetle generation emerged in fall and the remainder overwintered under the bark of their brood trees. Likewise, most predatory beetles and flies spent wintertime with their prey under the bark, while most parasitic wasps emerged in fall. The spring emergence of bivoltine predatory beetles was found to occur up to 3 weeks earlier than that of I. typographus, while that of the predatory flies and the parasitoids was delayed by up to 1 month. In univoltine populations, the bark beetles emerged several weeks prior to most antagonistic taxa. In the heat year 2003, three I. typographus generations were produced at the lower location, 36% of the third generation emerged in fall, while the proportions of overwintering predators remained largely the same as in previous years. Similar to their host, more parasitoids left their brood trees in fall after warm years. The results show that sanitation felling during winter probably kills most bark beetles in bivoltine populations, but also eliminates many natural enemies. In univoltine populations, sanitation felling might be less detrimental to both I. typographus and natural enemies because a fair fraction of their populations will already have left the trees before cutting. Warmer climates may affect the interactions of bark beetles and natural enemies and thus the impact of control measures.     

Yeasts from U.S.A. soils

Summary Investigations of yeasts from 38 U.S.A. soils samples show the occurrence of 22 different species (16 sporogenous and 6 asporogenous).The most widespread species were Pichia fermentans and Hansenula anomala. The other isolated species were Saccharomyces ellipsoideus, Torulaspora delbrueckii, Pichia membranefaciens, Saccharomyces smittii, Saccharomyces carlsbergensis, Saccharomyces uvarum, Torulaspora rosei, Zygosaccharomyces rouxii, Zygosaccharomyces n. sp., Hansenula saturnus, Hansenula californica, Hansenula n. sp., Hansenula suaveolens, Debaryomyces n. sp., Torulopsis glabrata, Torulopsis n. sp. Candida tropicalis, Candida robusta, Rhodotorula glutinis, Trichosporon cutaneum and Trichosporon cutaneum var. multisporus.     

Four new species of yeast isolated from insect frass in bark ofTsuga heterophylla (Raf.) Sargent

Summary In a study of the yeasts associated with insect frass underneath the bark ofTsuga heterophylla (the Pacific Coast hemlock) four new species of yeast were found. These were described asSporobolomyces singularis, Bullera tsugae, Cryptococcus skinneri andCandida oregonensis. Sporobolomyces singularis is a non-pigmented species, which required an amendment of the genus definition. Ballistospore formation of the new species ofSporobolomyces and ofBullera was absent on malt agar and on potato glucose agar, but positive on corn meal agar. An unusual case of quantitative transgalactosylation by growing cells ofSporobolomyces singularis on lactose has been described. It has been proposed to establish a “Candida parapsilosis Group” of species to whichC. oregonensis was assigned. Supported by a fellowship of the Calouste Gulbenkian Foundation, Lisbon, Portugal.     

Exogenous application of methyl jasmonate elicits defenses in Norway spruce (Picea abies) and reduces host colonization by the bark beetle Ips typographus

The terpenoid and phenolic constituents of conifers have been implicated in protecting trees from infestation by bark beetles and phytopathogenic fungi, but it has been difficult to prove these defensive roles under natural conditions. We used methyl jasmonate, a well-known inducer of plant defense responses, to manipulate the biochemistry and anatomy of mature Picea abies (Norway spruce) trees and to test their resistance to attack by Ips typographus (the spruce bark beetle). Bark sections of P. abies treated with methyl jasmonate had significantly less I. typographus colonization than bark sections in the controls and exhibited shorter parental galleries and fewer eggs had been deposited. The numbers of beetles that emerged and mean dry weight per beetle were also significantly lower in methyl jasmonate-treated bark. In addition, fewer beetles were attracted to conspecifics tunneling in methyl jasmonate-treated bark. Stem sections of P. abies treated with methyl jasmonate had an increased number of traumatic resin ducts and a higher concentration of terpenes than untreated sections, whereas the concentration of soluble phenolics did not differ between treatments. The increased amount of terpenoid resin present in methyl jasmonate-treated bark could be directly responsible for the observed decrease in I. typographus colonization and reproduction.     

The yeasts of British fresh sausage and minced beef

Three hundred and eighty three yeasts isolated from samples of unsulphited or sulphited sausages and skinless sausages and minced beef were characterized in detail.Debaryomyces hansenii was the most commonly isolated yeast from most samples followed byCandida zeylanoides andPichia membranaefaciens. The presence of sulphite in sausages did not appear to affect the numbers and range of yeasts present but did affect their relative proportions. A survey of one factory showed that meat intended for sausage production and equipment harboured the same range of yeasts that are found in the finished products.     

Effect of formaldehyde on the level of cytochrome c in methylotrophic yeasts

The effect of formaldehyde on the cytochrome system of the methylotrophic yeasts Candida tropicalis, Candida boidinii, Candida methylica, Hansenula capsulata, Hansenula polymorpha, Pichia pastoris and nonmethylotrophic yeasts Saccharomyces cerevisiae was studied. In the investigated concentration range of 0.58 – 2.5 mol · 1^?1, formaldehyde decreases the level of the reduced cytochrome c in the above-mentioned microorganisms. The kinetics of the change in the reduced cytochrome c content has two phases: a phase of slow decrease and a phase of complete disappearance of the reduced cytochrome c in the cells. The duration of the first phase shortens with increasing concentrations of formaldehyde.     

Host tree resistance influencing pheromone production in Ips typographus (Coleoptera: Scolytidae)

Analyses of volatiles in hindguts of Ips typgraphus males from different spruce trees and attack phases are reviewed. The composition of monoterpenes, and the chirality of α-pinene, have been determined in phloem samples. Relationships between compounds emanating from spruce trees and bark beetles, respectively, have been studied. Male beetles depend on their host tree for the production of pinene alcohols. The ratio between the pinene alcohols is almost constant in males boring in the same tree but can vary widely between males from different spruce trees. Very good correlations were found between some host tree monoterpene hydrocarbons and bark beetle produced pinene alcohols. The production of the essential pheromone component 2-methyl-3-buten-2-ol, was not correlated with the monoterpene content in the host trees, while the production of the other essential pheromone component, cis-verbenol, depends on the amount of the precursor, (−)-α-pinene in the phloem. Male beetles boring in a resistant spruce tree will continue to produce the pinene alcohols, including cis -verbenol, as long as the tree defends itself with resin.     

Yeasts in some Netherlands soils

Summary In 12 Netherlands soil samples, in two successive analyses carried out in the autumn of 1952, the author has isolated up to 105 cultures of yeasts to be classified under the following species:Kloeckera apiculata, Torulopsis inconspicua, Torulopsis pulcherrima, Candida Guilliermondii, Rhodotorula mucilaginosa, Aureobasidium pullulans, Hansenula saturnus, Hansenula californica, Saccharomyces mangini, Saccharomyces ellipsoideus andPichia membranefaciens. In all the soils examined the quantity of yeasts found has been very small. The results obtained do not offer evidence for any relationship between manurial treatment and species and number of yeasts occurring. Sporeforming yeasts were less numerous than non-sporeforming ones.

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Riassunto Da 12 terreni Olandesi, in due successive analisi, eseguite nell'autunno 1952, l'A. riferisce di avere isolato ben 105 colture pure di lieviti da riportare alle seguenti specie:Kloeckera apiculata, Torulopsis inconspicua, Torulopsis pulcherrima, Candida Guilliermondii, Rhodotorula mucilaginosa, Aureobasidium pullulans, Hansenula saturnus, Hansenula californica, Saccharomyces mangini, Saccharomyces ellipsoideus ePichia membranefaciens. In tutti i terreni esaminati la quantità di lieviti riscontrati è stata molto esigua; non è stata posta in evidenza alcuna influenza in rapporto alle diverse concimazioni ed è stata rilvata la scarsissima diffusione delle specie sporigene su quelle incapaci di formare spore.

     

Yeast associations with mosquitoes of the genus Aedes Mg. (Diptera, Culicidae) in the Tom-Ob river region

The inner microflora of blood-sucking mosquitoes genus Aedes inhabiting different biotops of aspen-birch woods of the Tomsc Priob region has been investigated. 120 strains of yeasts genera Pichia, Hansenula, Saccharomyces, Torulaspora, Metschnicowia, Rhodotorula, Cryptococcus, Candida and Aueobasidium have been isolated, the most number of species belong to the genus Pichia. Yeasts P. guilliermondii, A. pullulans and M. pulcherrima have been found during all periods of insects collection. The most number of yeasts species has been found in mosquitos of mass species--A. diantaeus, A. excrucians. A. punctor and A. communis. It is supposed that isolated yeasts are collected by mosquitoes off natural substrates in the course of their development.     

Isolation of the Melanization and Reddish Coloration Hormone (MRCH) of the Armyworm,Leucania separata,from the Silkworm,Bombyx mori

Two types of glycerol dehydrogenase (GDH) were found on DEAE-cellulose column chromatography of cell-free extracts of methylotrophic yeasts. One type, designated as GDH I, showed only the reductive activity which was detected in the reaction system containing dihydroxyacetone and NADH, at pH 6.0. The other type, designated as GDH II, showed the oxidative activity which was detected in the system containing glycerol and NAD ⁺, at pH 9.0, together with the reductive activity.

Candida boidinii No. 2201, which possesses the phosphorylative pathway for glycerol dissimilation, had only GDH I when grown on glycerol or methanol as the carbon source. Hansenula ofunaensis, which has the oxidative pathway, had both GDH I and GDH II when grown on glycerol, but only GDH I when grown on methanol. Hansenula polymorpha Dl-1, which has both pathways, had both GDH I and GDH II when grown on glycerol or methanol.     

Interactions ofCandida albicans with bacteria and salivary molecules in oral biofilms

The yeastCandida albicans coaggregates with a variety of streptococcal species, an interaction that may promote oral colonization by yeast cells.C. albicans andCandida tropicalis are the yeasts most frequently isolated from the human oral cavity and our data demonstrate that both these species bind toStreptococcus gordonii NCTC 7869 while two otherCandida species (Candida krusei andCandida kefyr) do not. Adherence ofC. albicans was greatest when the yeast had been grown at 30° C to mid-exponential growth phase. For 21 strains ofC. albicans there was a positive correlation between the ability to adhere toS. gordonii and adherence to experimental salivary pellicle. Whole saliva either stimulated or slightly inhibited adherence ofC. albicans toS. gordonii depending on the streptococcal growth conditions. The results suggest that the major salivary adhesins and coaggregation adhesins ofC. albicans are co-expressed.     

Yeasts associated with pods and exudates of algarrobo trees (Prosopis spp.) and species of columnar cacti in northwest Argentina

Yeasts were isolated from exudates of algarrobo trees from nine sites in northwest Argentina, three in the Chaco region, from pods of algarrobo and acacia, collected in the Quebrada de Cafayate, and from rot pockets in decaying columnar cacti at Cachi (Parc Nacional des Cardons), and at Las Ruinas de Quilmes. Most of the yeasts isolated from exudates of algarrobo were identified asBullera variabilis, Candida famata, Cryptococcus albidus and otherCryptococcus species,Debaryomyces hansenii, Pichia angusta (Hansenula polymorpha),Pichia ciferrii, Pichia farinosa andTorulaspora delbrueckii. OtherCandida, Kluyveromyces andPichia species were found. Most species were osmotolerant. The high sugar content of the exudates influenced the nature of the yeast species present. The pods containedCryptococcus spp.,Candida famata andCandida ciferrii spp. Half the species isolated from rotting cactus wereCryptococcus species.Pichia membranaefaciens andTorulaspora delbrueckii were also isolated. Of 553 cultures investigated, 49 utilized methanol.Deceased on July 24th, 1995