Minuta Var Research Articles

Bioefficacy of bacteria and yeast bioagents on disease suppression and quality retention of stored Kinnow mandarin fruits

Kinnow mandarin is a high value citrus crop in the fruit industry. However, the fruits are vulnerable to a variety of phytopathogens and suffer huge quantitative and qualitative losses. Pathogenic filamentous fungi like Penicillium digitatum, Penicillium italicum, and Geotrichum candidum are mainly responsible for postharvest losses. Alternative to synthetic fungicides, the bacteria and yeast-based biocontrol approaches are the most efficient means for controlling postharvest diseases. The antagonistic potential of five biocontrol agents such as Debaryomyces hansenii, Lactobacillus plantarum, Metschnikowia pulcherima, Pichia guilliermondi and Rhodotorula minuta var. minuta was assessed under both in vitro and in vivo conditions against the mycelial growth of postharvest pathogens using dual culture method. The results revealed that R. minuta var. minuta was the most promising antagonist with 71.98%, 76.18% and 67.46% mean mycelial growth inhibition of P. digitatum, P. italicum and G. candidum respectively, over untreated potato dextrose agar (PDA) plates after 192 h of incubation under in vitro. Further, under in vivo, the fruits treated with R. minuta var. minuta did not impair the quality and sensory attributes during ambient storage. Hence, R. minuta var. minuta proved an eco-friendly and safer substitute to synthetic fungicides for postharvest disease management of Kinnow mandarin fruits.

Selection of the methylotrophic yeast Ogataea minuta as a high-producing host for heterologous protein expression

Three Ogataea minuta var. minuta strains have been deposited as NBRC 0975, NBRC 10402, and NBRC 10746 in the National Institute of Technology and Evaluation (NITE) Biological Resource Center (NBRC) collection. We investigated the ability to produce secretory proteins and several genotypic and phenotypic characteristics in order to select the best strain for heterologous protein expression. NBRC 10746 showed the best performance as evaluated by Cypridina noctiluca luciferase expression. Subsequently, clone #5-30 named tat06213, which was obtained by single-colony isolation from NBRC 10746, was established as a promising host for heterologous protein expression. To deepen our understanding of the characteristics of O.minuta var. minuta strains, sequence analysis of the D1/D2 domain of large subunit rRNA was conducted and the resulting phylogenetic tree derived from the D1/D2 domain showed that NBRC 10402 and NBRC 10746 were grouped into a different cluster far from NBRC 0975. Furthermore, a chromosome structure topology with electrophoretic karyotype and AOX1 loci analyzed by pulsed-field gel electrophoresis with Southern blotting showed different chromosome patterns and AOX1-hybridization loci among the strains. Additionally, the sequences of the promoter regions of the cloned AOX1 genes were not identical among the three strains. These findings might explain the differences in heterologous protein expression among the tested O. minuta var. minuta strains.

Two new varieties of Russula Pers. (Basidiomycota: Russulaceae) from Sal forests of Shiwaliks, India

This paper deals with two new varieties of Russula species, R. camarophylla var. reticulospora var. nov. and R. aurea var. minuta var. nov. These were collected from the Shiwalik range of northwestern India, in association with Shorea robusta. Russula aurea var. minuta differs from R. aurea in having small sized sporophores, dentate to wavy gill edges with golden or yellow deposition instead of smooth and much smaller spores. Whereas, mushroom R. camarophylla var. reticulospora is close to Russula camarophylla except for the larger carpophores that have white cream pileus surface and larger spores. In basidiospores warts are connected to form mostly complete reticulum instead of mostly isolated warts reported in Russula camarophylla. In view of the presence of some unique varied features in the presently examined collections two new varieties of Russula has been proposed.

Two New Taxa of <i>Ecballocystopsis</i> (Chlorophyta) from Eastern India

Two new taxa of the genus Ecballocystopsis Iyengar (Chlorococcales, Chlorophyta), E. himalayansis sp. nov. and E. dichotomus var. minuta var. nov. occurring in two different localities, one in a water fall in Sikkim-Himalayas and another in a stream in Odisha are described. The former is the fourth species of Ecballocystopsis so far reported and the later is a variety of E. dichotomus Zheng-Yu et Lie-Jue earlier recorded from China. Comparative account of the morphological features of these species has been presented.

Investigating of yeast species in wine fermentation using terminal restriction fragment length polymorphism method

The objective of this study was to examine the potential of terminal restriction fragment length polymorphism (T-RFLP) in monitoring yeast communities during wine fermentation and to reveal new information on yeast community of Chinese enology. Firstly, terminal restriction fragment (TRF) lengths database was constructed using 32 pure yeast species. Ten of these species were firstly documented. The species except for Candida vini, Issatchenkia orientalis/Candida krusei, Saccharomyces bayanus, Saccharomyces pastorianus, Saccharomyces cerevisiae, Saccharomyces kudriarzevii and Zygosaccharomyces bisporus could be distinguished by the T-RFLP targeting 5.8S-ITS rDNA. Moreover, the yeast communities in spontaneous fermentation of Chardonnay and Riesling were identified by T-RFLP and traditional methods, including colony morphology on Wallerstein Nutrient (WLN) medium and 5.8S-ITS–RFLP analysis. The result showed that T-RFLP profiles of the yeast community correlated well with that of the results identified by the traditional methods. The TRFs with the highest intensity and present in all the samples corresponded to Saccharomyces sp. Other species detected by both approaches were Hanseniaspora uvarum, Metschnikowia pulcherrima, Pichia minuta var. minuta, Saccharomycodes ludwigii/Torulaspora delbrueckii and Candida zemplinina. This study revealed that T-RFLP technique is a rapid and useful tool for monitoring the composition of yeast species during wine fermentation.

A Survey of the Gomphonemaceae and Cymbellaceae (Bacillariophyta) from the Jolmolungma Mountain (Everest) Region of China

ABSTRACT Gomphonemaceae and Cymbellaceae from Jolmolungma Mountain region of China, comprised 79 taxa belonging to five genera. The dominant species were Gomphonema angustatum var. productum, G. gracile var. gracile, G. parvulum var. parvulum, G. hedini, Cymbella aequalis var. pisciculus, C. delicatula, C. cistula, C. cistula var. hebetata, C. cesatii, C. cymbiformis, C. microcephala, C. minuta var. minuta, C. minuta var. silesiaca, C. pusilla, C. affinis. Some arctic and alpine forms also occurred, and the following taxa were unique to this region: Cymbella delicatula, C. naviculiformis, C. gracilis, C. minuta var. minuta, C. affinis, C. cistula, C. cymbiformis, C. cistula var. hebetata, C. arctica, Didymosphenia geminata, Gomphonema hedinii, G. olivaceum. Numbers of taxa in each samples varied greatly. It appears that species diversity of diatoms is related not only to macro-environments (e.g., geographic zonation) but also to micro-environments (e.g., microhabitats and microclimates). Cymbella spp. are not only comparatively widespread in the region but also outnumber Gomphonema spp. A large number of species found in the Jolmolungma Mountain region are also found in Tibet and the headwaters of Yangtze River.

A taxonomic reassessment of the varieties of Oxalis minuta (Oxalidaceae) and the change of O. minuta var. callosa to specific rank as O. hygrophila

O . minuta Thunb. var. callosa Salter was included in section Sagittatae of the genus Oxalis L., based on superficial morphological resemblance to O . minuta var. minuta . We questioned this placement due to the reticulate pollen grains displayed by this taxon, whereas members of section Sagittatae have rugulate-reticulate pollen grains. A lack of good herbarium and living specimens prohibited a better taxonomic placement of this taxon. Living plants were recently found in the Pakhuis Pass (Western Cape, South Africa), which enabled this re-assessment of its taxonomic affinities. A suite of morphological and palynological characters were identified that differ significantly from both the typical variety and all other members presently included in section Sagittatae . These include the ovate to elliptic anthers, the orientation of long and mid-level reproductive organs, the absence of an indumentum on the leaves, the presence of calli on the leaflets, sepals and petals, reticulately deposited epicuticular wax on the leaves, the broadly funnel-shaped corolla tube and the basally fused anthers. We therefore raise Oxalis minuta var. callosa to specific rank as O . hygrophila Dreyer, and transfer it from section Sagittatae to section Latifoliolatae .

Cold marine indicators of the late Quaternary: the new dinoflagellate cyst genus Islandinium and related morphotypes

AbstractRound, brown, spiny dinoflagellate cysts characterise many modern high‐latitude assemblages. Abundance is often highest where summer sea‐surface temperatures seldom exceed 7 °C and where winter sea‐surface temperatures are around 0 °C, making this morphological group important for reconstructing cold intervals within marine Quaternary sequences. Our analysis of modern sediments from the Beaufort Sea of Arctic Canada, the Kara and Laptev seas of Arctic Russia, and across the Arctic Ocean, allows us to recognise the new cyst genus Islandinium along with the extant species Islandinium minutum (Harland and Reid in Harland et al., 1980) new combination (basionym: Multispinula? minuta), Islandinium? cezare (de Vernal et al., 1989 ex de Vernal in Rochon et al., 1999) new status and combination (basionym: Multispinula? minuta var. cezare) sensu lato, and Echinidinium karaense new species. Of these, the generotype Islandinium minutum is a well‐known but morphologically problematic species. We have re‐examined the type material from the Beaufort Sea and studied specimens from across the Arctic, and our observations clarify ambiguities in the original description of this species. The archeopyle of Islandinium minutum results from the loss of three apical plates, an unusual style among peridiniphycidean dinoflagellates. The asymmetrical location of these plates around the apex is distinctive, and probably contributed to earlier misunderstandings of the archeopyle. Previous attributions to Multispinula? and Algidasphaeridium? are unsustainable. Maps showing the distribution of Islandinium minutum are given for the Northern Hemisphere and show this species to be polar to north‐temperate, whereas Islandinium? cezare s.l. and Echinidinium karaense appear to be more restricted to polar environments. Copyright © 2001 John Wiley & Sons, Ltd.

Some aspects on the morphology and ecology of Rhodomonas minuta var. nannoplanctica and R. lens (Cryptophyceae) in two Greek lakes

Significant morphological and ecological differences between Rhodomonas minuta var. nannoplanctica and R. lens were observed during the study of phytoplankton in two Greek lakes. The shape and size characteristics support the validity of these species, so the fusion of closely related species of Rhodomonas proposed by Javornicky is not accepted in this study. Apart from the morphological differences between Rhodomonas minuta var. nannoplanctica and R. lens contrasting ecological requirements were noticed. A broader distribution of Rhodomonas minuta var. nannoplanctica in relation to temperature and pH and a preference for lower nutrient concentrations than R. lens were found. The two taxa may coexist by shifting their niches at different times in Lake Volvi and by vertical niche separation in Lake Vegoritis.

Regulation of phytoplankton dynamics in a Laurentian Great Lakes estuary

The composition and dynamics of phytoplankton populations were examined in Old Woman Creek estuary, Lake Erie (USA). The centric bacillariophytes,Cyclotella atomus Hust.,Cyclotella meneghiniana Kutz., andAulacoseira alpigena (Grun.) Krammer, and the cryptophytes,Cryptomonas erosa Ehren. andRhodomonas minuta var. nannoplanctonica Skuja, dominated the phytoplankton most of the year. Chlorophytes, euglenophytes, and cyanophytes were observed less frequently. Estuarine and Lake Erie phytoplankton were considered distinct populations; lake taxa were largely confined to the estuary mouth and present only in low biomass. Maxima and minima of estuarine phytoplankton coincided with meteorological and hydrological forcing in the form of rainfall and subsequent storm-water inflows, respectively. Distinct population dynamics between the upper and lower estuary following storm events were attributed to the presence/absence of refugia serving as a source for repopulation by opportunistic taxa, fluctuating light conditions in the water column resulting from influx of particulate matter and resuspension of bottom sediments, and nutrient inputs associated with surface runoff and sub-surface interflow. Additionally, agricultural herbicides introduced by storm-water inflows potentially may affect and/or control the growth and physiological responses of individual taxa.

Some wood-inhabiting yeasts of trembling aspen (Populus tremuloides) from Alberta and northeastern British Columbia

In a survey of wood-inhabiting fungi of trembling aspen, nine species of yeast fungi were re? covered from wood of 19 individual trees from four localities in western Canada. Identification of the iso? lates revealed that Pichia minuta var. minuta, a species apparently restricted to Populus, in addition to Can? dida ernobii and Cryptococcus skinneri were the taxa most frequently encountered. This report extends the known substrate and geographic range for most of the species found.

The phylogenetic relationships of the hat-shaped ascospore-forming, nitrate-assimilating Pichia species, formerly classified in the genus Hansenula Sydow et Sydow, based on the partial sequences of 18S and 26S ribosomal RNAs (Saccharomycetaceae): the proposals of three new genera, Ogataea, Kuraishia, and Nakazawaea.

The twenty-seven strains of the hat-shaped ascospore-forming, nitrate-assimilating species, formerly classified in the genus Hansenula, of the genus Pichia were examined for their 18S and 26S rRNA partial base sequencings. All the strains examined were separate phylogenetically from the type strain of P. membranaefaciens (type species of genus Pichia). Based on the sequence data obtained [by number of base differences (five or more) with P. anomala and base sequences on fingerprint segment] in the 18S rRNA partial base sequences, these species were divided into seven groups. Group I, including P. anomala (identical to H. anomala, type species of genus Hansenula), P. canadensis, P. muscicola, P. silvicola, P. subpelliculosa, P. americana, P. bimundalis, P. ciferrii, P. syndowiorum, P. bispora, and P. fabianii, corresponded to the genus Hansenula Sydow et Sydow. Groups II and III were comprised of P. capsulata and P. holstii, respectively. Group IV included P. angusta, P. minuta var. minuta, P. minuta var. nonfermentans, P. philodendra, P. glucozyma, and P. henricii. Groups V, VI, and VII included P. jadinii, P. petersonii, and P. dryadoides, respectively. The nitrate assimilation-negative species, P. wickerhamii was phylogenetically distant from P. membranaefaciens. The seven groupings are discussed phylogenetically and taxonomically. For Groups IV, II, and III, the three new genera were proposed as Ogataea, Kuraishia, and Nakazawaea, respectively, with the type species, O. minuta (identical to P. minuta), K. capsulata (identical to P. capsulata), and N. holstii (identical to P. holstii).

The ecology of Synchaeta kitina Rousselet in Loch Leven, Scotland

Synchaeta kitina Rousselet reached population densities of up to 5000 ind.l−1 in Loch Leven, between January 1977 and December 1982. The species was found over the entire range of temperatures recorded (0.4–21.4 °C), but was most abundant at temperatures above 7 °C. Embryo development times, determined under laboratory conditions, ranged from 122 h at 2 °C to 12.5 h at 20 °C. There was a marked inverse relationship between populations of S. kitina and Daphnia hyalina var. lacustris in the loch. It seems unlikely that this was due to interference competition from Daphnia. S. kitina can be cultured on Rhodomonas minuta var. lacustris and there is some evidence that this rotifer also feeds on small flagellates in its natural environment.

Migration behaviour of three cryptophytes in relation to environmental gradients: an experimental approach

The diurnal vertical migration (DVM) behaviour of three species of cryptophytes of differing size (Rhodomonas minuta var. nannoplanctica and two species of Cryptomonas) was examined in 4 m tall laboratory columns in relation to gradients of light, temperature and nutrients. Differences were found in the DVM behaviour of the three species in relation to these environmental variables. Both species of Cryptomonas were able to cross steep thermal gradients whereas Rhodomonas did not. All three species avoided high levels of irradiance, especially when the cells were phosphorus-depleted. The large species of Cryptomonas made use of vertically separated resources of light and phosphorus by migrating from the illuminated, but phosphorus-depleted, upper layer during daytime to the phosphorus-rich hypolimnion at night. The smaller species of Cryptomonas had a reverse pattern of DVM swimming upwards during darkness, indicating a strong negative geotaxis. Moreover, downward migration of this smaller Cryptomonas ceased abruptly at the thermocline giving rise to well developed mid-water maxima in contrast to the larger species. The migration speeds of the Cryptomonas species were up to 0·7 m h-1 and cells were able to move quickly in response to environmental changes in the water column. The results demonstrate the importance of both the physiological state of the cells and the external physical and chemical conditions, particularly irradiance, as factors regulating the DVM behaviour of cryptophytes.

Seasonal and spatial distribution of cryptophycean species in the deep, stratifying, alpine lake Mondsee and their role in the food web

Quantitative data are presented on the depth-time distribution of four cryptophycean species (Cryptomonas marssonii, C. cf. ovata, C. pusilla and Rhodomonas minuta var. nannoplanktica) over a three year investigation period in Mondsee, Austria, a deep, stratifying alpine lake. Net rates of population increase and decrease are calculated and related to environmental variables (temperature, light, turbulence) and impact by herbivorous zooplankton. Although cryptophyceans rarely comprise more than 15 – 20% of total phytoplankton biovolume they contribute considerably to plankton community dynamics.

Yeast flora of non-radurised and radurised minced beef — a taxonomic study

Yeast flora present in minced beef before and after radurisation were examined. No reduction in the number of yeast cells was observed after the meat was radurised at a dose of 2.5 kGy. A definite increase in the number of psychrotrophic yeast was observed in radurised meat after 14 days of storage at 4°C. The recovered yeast flora comprised representatives of the following species: Candida famata (9 isolates); C. lipolytica (4 isolates); C. parapsilosis (20 isolates); C. sake (27 isolates); C. zeylanoides (28 isolates); Cryptococcus albidus var. albidus (6 isolates); Cr. infirmo-miniatus (1 isolate); Cr. laurentii var. laurentii (31 isolates); Trichosporon cutaneum (1 isolate); Tr. pullulans (2 isolates); Rhodotorula minuta var. texensis (1 isolate); Rh. rubra (1 isolate).

Taxonomic Significance of Electrophoretic Comparison of Enzymes in the Genera Rhodotorula and Rhodosporidium

We used polyacrylamide slab gel electrophoresis with specific staining for seven enzymes to compare 108 strains belonging to the genera Rhodotorula and Rhodosporidium. The patterns obtained allowed us to divide the strains of Rhodotorula glutinis and its varieties into six groups. The strains of Rhodotorula rubra and Rhodotorula pilimanae examined had identical patterns. Rhodotorula minuta var. minuta and Rhodotorula minuta var. texensis clearly differed from Rhodotorula glutinis and Rhodotorula rubra in their hexokinase and 6-phosphogluconate dehydrogenase patterns. Rhodotorula marina, Rhodotorula pallida, and Rhodotorula lactosa each had a characteristic pattern. We found three haploid mating type strains to mating type a of Rhodosporidium toruloides, mating type a of Rhodosporidium sphaerocarpum, and mating type a of Rhodosporidium diobovatum among the strains of Rhodotorula glutinis var. rufusa, Rhodotorula glutinis var. salinaria, and Rhodotorula glutinis var. glutinis by performing conjugation tests to confirm the relationships that were revealed when the enzyme patterns were compared. In the genus Rhodosporidium, compatible mating type strains showed similar enzymatic patterns. Strains of Rhodosporidium toruloides which could not assimilate potassium nitrate had the same enzymatic patterns as those that could.

Stereoselective synthesis of ectocarpene and its antipode via microbiological asymmetric hydrolysis.

Biological asymmetric hydrolysis of ethyl (±)-cycloheptadienecarboxylate with Rhodotorula minuta var. texensis IFO 1102 and chemical resolution of the corresponding carboxylic acid with (−)-quinine provided (R)-(+)-ethyl 2,5-cycloheptadienecarboxylate (78% e.e.) and (S)-(+)-2,5-cycloheptadienecarboxylic acid (95% e.e.), respectively. The (R)-(+)-carboxylate was converted to (R)-(−)-2,5-cycloheptadienylcarbaldehyde and the (S)-(+)-carboxylic acid to (S)-(+)-2,5-cycloheptadienylcarbaldehyde. Ectocarpene (78% e.e.), male-gamete attractant of marine brown alga, and its antipode (95% e.e.) were synthesized by stereoselective Wittig reaction between the (R)-(−)- and (S)-(+)-aldehydes and propyltriphenylphosphonium bromide in a liquid-solid two phase system using 18-crown ether-t-BuOK, respectively.

Bioconversion of lipophilic compounds by immobilized microbial cells in organic solvents

AbstractMicrobial cells were gel‐entrapped with photo‐crosslinkable resin prepolymers or urethane prepolymers, respectively. The resulting gels have different tailor‐made hydrophobic or hydrophilic character. They were used for successful bioconversion of hydrophobic steroids and terpenoids in watersaturated mixtures of organic solvents. The experiments show the influence of the hydrophobicity of the gels and the polarity of the solvent mixtures, respectively. Use of hydrophobic gels and less polar solvents is preferable for bioconversion of hydrophobic compounds. The selective formation of a desired product among diverse products from a single substrate by appropriate use of hydrophobic or hydrophilic gels is possible. In each case, tests should be made to select the appropriate gel and solvent mixture. Bioconversions tested are: dehydroepiandrosterone to 4‐androstene‐3,17‐dione; cholesterol to cholestenone; β‐sitosterol to β‐sitostenone; stigmasterol to stigmastenone; pregnenolone to progesterone; testosterone to Δ1‐dehydrotestosterone or 4‐androstene‐3,17‐dione, respectively; all with immobilized cells of Nocardia rhodocrous; and stereoselective hydrolysis of dl‐menthyl‐succinate to yield l‐menthol with immobilized cells of Rhodotorula minuta var. texensis.

Stereoselective hydrolysis of dl-menthyl succinate by gel-entrapped Rhodotorula minuta var. texensis cells in organic solvent

dl-Menthyl succinate was successfully hydrolyzed stereoselectively by Rhodotorula minuta var. texensis cells entrapped within photo-crosslinked or polyurethane resin gels in water-saturated n-heptane. The hydrolyzed product was found to be pure l-menthol. The catalytic activity of the immobilized cells, especially those entrapped in urethane polymers, was far more stable than that of the free cells. The half-life of the polyurethaneentrapped cells was estimated to be 55–63 days in the organic solvent.