Carotenoids of Phaffia rhodozyma, a red-pigmented fermenting yeast

The red-pigmented fermenting yeast Phaffia rhodozyma contains astaxanthin as the principal carotenoid pigment. Echinenone, 3-hydroxyechinenone and phoenicoxanthin were also isolated and identified; isocryptoxanthin and canthaxanthin were absent. Evidence is presented for a new carotenoid, 3-hydroxy-3′4′-didehydro-β,ψ-caroten-4-one. A possible biosynthetic scheme for the formation of astaxanthin in P. rhodozyma is suggested.     

Effect of species, age, and sex of tsetse on response to infection by Metarhizium anisopliae

Laboratory studies were carried out to determine the effect of sex and age on the susceptibility of tsetse, Glossina morsitans morsitans and G. m. centralis, to the entomopathogenic fungus, Metarhizium anisopliae. Both species of host flies were susceptible to fungal infection. Female flies were generally more susceptible than male flies. Three host ages (40, 20, and <1 day-old) were used; the youngest group was most resistant to fungal infection. Interactions between species, sex and age were significant on many occasions. Age usually accounted for the largest variability in mortality, followed by sex. All flies of age 40 days died between 7 and 8 days after infection whereas some of the younger flies, especially age 0, lived longer than 10 days. Log10 day probit (LDP) mortality regressions fitted well to most of the data sets. LDP slopes were significant and high, ranging between 4.3 and 12.8, indicating a generally high mortality rate of increase over days. The slopes differed significantly between species, sexes, and ages, but grouping by age was more intra homogeneous than by species or sex. The 50% lethal time mortalities (LT50) ranged between 4 and 7 days for age 0, 3 and 6 days for age 20, and about 5 days for age 40. Corresponding ranges of the LT95 were 8 to 20, 5 to 10, and 6 to 7 days for ages 0, 20 and 40, respectively. The significance of these results in the fungal disease transmission by tsetse is discussed.     

A fungal phylogeny based upon orotidine 5′-monophosphate decarboxylase

Summary Orotidine 5-monophosphate decarboxylase protein sequences from 14 fungi, 1 slime mold, 2 mammals, and 3 bacteria are compared and aligned and shown to be homologous. Based on the optimal alignment of the fungal sequences, a phylogenetic tree is derived. Within the fungi, the fission yeast Schizosaccharomyces pombe shows a closer relationship to both basidiomycetes and phycomycetes than it does to orthodox ascomycetes (plectomycetes, pyrenomycetes, and budding yeasts). Intron conservation shows a close relationship between phycomycetes and basidiomycetes. The imperfect fungi Trichoderma and Cephalosporium are shown to be closely related to Neurospora. The predicted origin of the group of budding yeasts is dependent on the analytical method used.     

Naphthoquinones produced by Fusarium solani isolated from citrus

Eleven naphthoquinone pigments are described which were produced by F. solani isolates obtained from roots of diseased citrus trees. One of these pigments was shown to be the precursor for six of the isolated compounds.     

Entomopathogens from two Chihuahuan desert localities in Mexico

A list of entomopathogens from two Chihuahuan desertlocalities in México is given. Rhabditid nematodes, nuclear polyhedrosis viruses, a rickettsia(Rickettsiella popilliae), the fungi Beauveria bassiana,Entomophaga calopteni (= Entomophaga gryllipathotype 2),Entomophthora muscae, Entomophthora planchoniana,Furia vomitoriae, Nomuraea rileyi, Metarhiziumanisopliae var. anisopliae, Pandora gammae, Pandoraneoaphidis and Zoophthora radicans, and the microsporidian Nosema weiseri were all collected from the campus of the UniversidadAutónoma Agraria Antonio Narro, near the city of Saltillo, state of Coahuila, México. Metarhizium anisopliae var. anisopliae and Paecilomyces fumosoroseus were collected in the urban area of Saltillo. B.bassiana, Fusarium sp. (very similar toFusarium coccophilum),M. anisopliae and Paecilomyces farinosuswere collected in an appleorchard 50 km east of Saltillo. The nematodes, B.bassiana, E. calopteni, M. anisopliae, P.gammae, P. neoaphidis, and Z. radicans caused mortality levels of >10% in their respective hosts in the field. This revised version was published online in July 2006 with corrections to the Cover Date.     

嗜热真菌的分类研究一半知菌

根据嗜热真菌生境特点,从采集的600多份标本中分离鉴定到嗜热真菌15种,其中分离获得半知菌8种。对8种半知菌的形态特征进行了系统综合描述。     

Mycosporins from Ascochyta pisi, Cladosporium herbarum and Septoria nodorum

The chemical structure of the mycosporin isolated from Ascochyta pisi, Cladosporium herbarum and Septoria nodorum was established as mycosporin-2 glucoside.     

Biosynthesis of abscisic acid from farnesol derivatives in Cercospora rosicola

(E,E)?[1?¹⁴C]Farnesyl phosphate and (E,E)?[1?¹⁴C]farnesyl pyrophosphate were both converted to abscisic acid by Cercospora rosicola resuspensions. (E,E)?[1?¹⁴C]Farnesol, (E,Z)?[1?¹⁴C]farnesol, (E,Z)?[1?¹⁴C]farnesyl pyrophosphate, (E,E)?[1?¹⁴C]farnesic acid, and (E,Z)?[1?¹⁴C]farnesic acid were not converted to abscisic acid by the fungus. These findings provide information on the sequence of the reactions involved in converting farnesyl pyrophosphate to abscisic acid. Specifically, they suggest that the transformations involving the three terminal carbons in the side chain occur after one or more changes elsewhere in the molecule.     

(3R,3′R)-astaxanthin from the yeast Phaffia rhodozyma

Astaxanthin isolated from the yeast Phaffia rhodozyma has the 3R,3′R-configuration, opposite to that of astaxanthin from other sources which have been so far investigated. This is the first example of a naturally occurring carotenoid biosynthesized in different optical forms. A possible explanation is advanced.     

Persistence of augmented Metarhiziumanisopliae and Beauveria bassiana in Finnishagricultural soils

The persistence and penetration into soilof surface-applied unformulated conidia of twoisolates of Metarhizium anisopliae and one of Beauveria bassiana at sites with clay, peat andtwo kinds of sand as their soil types and at depthsof from 0 to 20 cm was studied in 1988–1991 underconditions characterized by permanent snow cover andfrozen soil in the winter time. At 0–5 cm depth, M. anisopliae persisted throughout the experiment atall sites, clay being the most and peat the leastfavourable soil for persistence. Clay and one of thesandy soils were the least and peat the most conducivesoil to penetration of M. anisopliae from thesurface to deeper soil layers and persistence therein.Differences in persistence were evident between thetwo M. anisopliae isolates in the sandy and peatsites, but not in the clay site. Three yearspostapplication there were still enough infectiouspropagules of M. anisopliae in soil of allsites to infect over 80% of the Tenebriomolitor larvae used as baits in samples taken fromthe cylinders of all soils. All the augmentedpropagules of B. bassiana disappeared duringthe first winter after application in clay and one ofthe two sandy sites, but some persistence one yearpostinoculation was evident at 0–5 depth in one ofthe sand soils and at 0–5 and 5–10 cm depths in peat.