Frequency of occurrence of mangrove fungi from the east coast of India

This paper describes the frequency of occurrence and biodiversity of fungi from mangroves of the Godavari and Krishna deltas, on the east coast of India. Seventy three species were identified from Godavari and 67 from the Krishna mangroves. Fifty five species were common to both sites, 18 were found only at Godavari and 12 at Krishna mangroves. Verruculina enaliawas found to be very frequent at both sites with a higher frequency of occurrence at Godavari. Eutypa bathurstensis was very frequent at Godavari but only frequent at Krishna. Cirrenalia pygmea and Cryptosphaeria mangrovei were frequent at the Godavari mangrove, but were recorded occasionally at Krishna. Decaying samples of Rhizophora and Avicennia were studied in detail. Forty three species were common to both hosts, while 22 species were recorded only from Avicennia and 20 only from Rhizophora. Verruculina enalia was the only very frequent fungus recorded on both hosts with a lower percentage occurrence (14.8%) on R. apiculata as compared to Avicennia spp. (24.3%). Eutypa bathurstensis was the next most frequent fungus on Avicennia, while Rhizophila marina was next most frequent on Rhizophora. Dactylospora haliotrepha which was recorded frequently on Rhizophorawas infrequent on Avicennia.     

Distribution of Mononchoidea (Nematoda: Enoplea) in pasture soils,with description of lotonchus stockdilli n. sp.

Abstract

Across 64 sites 8 species were found, with Clarkus propapillatus at 60 sites, C. composticola at 7, Prionchulus muscorum at 3, Mylonchulus ubis at 7, M. sigmaturus at 1, Cobbonchus australis at 9, lotonchus basidontus at 4, and I. stockdilli n. sp. at 3 sites. Sampling effort varied at the sites and significant annual and management effects have previously been reported on mononchid populations. No clear geographic or soil factor is apparent in the distributions, but more species may occur at sites with higher annual rainfall. lotonchus stockdilli n. sp. is a large (female L = 3.05–5.90 mm), bisexual species with dorsal tooth at the posterior of the sclerite, female tail about 400 μm or 14%, and no cuticular pores in the vulval region.     

Folded chromosomes of Saccharomyces cerevisiae

Folded chromosome phenotypes have been examined and compared in four cell-division-cycle (cdc) mutants during transitions between cycling and non-cycling states. The two start mutants, cdc 28 and cdc 25, can undergo G₀ arrest at the restrictive temperature. Arrest at start, defined by the cdc 28 and cdc 25 block points, is distinguishable from G₀ arrest. Arrest at the cdc 28 and cdc 25 block points can also be distinguished from each other: folded chromosomes appear to be destabilized at the cdc 25 block, but are stable at the cdc 28 arrest point. On the other hand, folded chromosomes from cdc 28 in sporulation medium at the restrictive temperature appear unstable, while chromosomes from cdc 25 are stable. The G₁ arrest mutants, cdc 4 and cdc 7, can undergo G₀ arrest at the restrictive temperature. In sporulation medium no meiotic replication form is detected at the restrictive temperature, although incorporation of labeled precursors into nuclear DNA does take place. A schematic model incorporating these various findings is presented.     

两种国兰C类花发育MADS基因的克隆与表达研究

该研究以蕙兰(Cymbidium faberi)和墨兰(Cymbidium sinense)为材料,利用RT-PCR对AGAMOUS (AG)基因进行克隆,并利用qRT-PCR进行组织表达.结果 表明:(1)获得3个AG基因均属于植物特有的C类MIKC型MADS-box基因,其中2个蕙兰AG基因命名为CfAG1(登录号...     

Syntheses of Unsaturated Lactones

6-Pentyl-α-pyrone, 6-propyl-α-pyrone and 4-decenoic acid-δ-lactone were prepared, and the nature of their flavors was investigated. Unsaturated lactones having the best flavorous nature as a butter or butter cake flavor among the lactones having double bond at various site, were 2-ene-δ-lactones which have a double bond at the α-position of the lactone ring and α-pyrones which have two double bonds at the α- and γ-positions. The flavor of 4-deceno-δ-lactone which has a double bond at the γ-position was the worst of them.     

Artificial control of cytoplasmic pH and its bearing on cytoplasmic streaming,electrogenesis and excitability of characeae cells

Effects of changing the cytoplasmic pH on the cytoplasmic streaming, membrane potential and membrane excitability were studied in tonoplast-free cells ofChara australis andNitellopsis obtusa. The cytoplasmic pH was varied by internal perfusion of pH-buffered media.Nitellopsis cells were perfused only once, whileChara cells were perfused twice to control the pH more accurately. In both materials the rate of cytoplasmic streaming was maximum at about pH 7, low at pH 8.5–9 and almost zero at pH 5–5.5. The membrane potential was most negative at about pH 7. InChara the membrane potential supported by Mg·ATP was strongly inhibited at pH 5.5, and almost zero at pH 9, supporting the results obtained by Fujiiet al. (1979) on cells ofChara australis which were perfused once. The action potential could be induced by electrical stimulation inChara at pH 6.0–9.0 and inNitellopsis at pH 6.6–7.9. The membrane resistance ofNitellopsis was high at acidic and neutral pH values and low at alkaline pH, while that ofChara was low at both acidic and alkaline pH values.     

Effect of osmotic potential on the growth of Gaeumannomyces graminis and Phialophora spp.

The linear growth of 10 isolates each of Gaeumannomyces graminis var. graminis, G. graminis var. tritici and Phialophora graminicola and five isolates each of G. graminis var. avenae and a lobed-hyphopodiate Phialophora sp. was studied on osmotically adjusted agar at 20 °C. While most isolates of G. graminis var. avenae ceased growing at osmotic potentials of -60 bars (1 bar = 10⁵ Pa), six out of 10 isolates of G. graminis var. tritici grew at that potential. The growth of all isolates of G. graminis var. tritici and var. avenae ceased at -70 bars. In contrast, four out of 10 isolates of P. graminicola grew at -70 bars, but all stopped growing at -80 bars. Most of the isolates of G. graminis var. graminis and the lobed-hyphopodiate Phialophora sp. grew at -70 bars while three out of 10 isolates of G. graminis var. graminis and one out of five isolates of the lobed-hyphopodiate Phialophora sp. were capable of growth at -80 bars. None of the fungi grew at -90 bars. Detailed studies of the growth of two or three isolates each of the five fungi at 10, 20, 30 and 35 °C were carried out on osmotic agar controlled by the addition of either sodium chloride or potassium chloride. In general, similar reductions in growth occurred with decreasing osmotic potential regardless of the solute used. At 10 and 20 °C., all three isolates of P. graminicola showed optimal growth at about -5 bars while the other fungi grew fastest at -1²middot; bars. At 30 °C., one isolate of the lobed hyphopodiate Phialophora sp. and two isolates each of P. graminicola, G. graminis var. tritici and G. graminis var. avenae grew optimally at osmotic potentials of -10 to -15 bars. The other isolate of the Phialophora sp. and two isolates of G. graminis var. graminis studied grew optimally at the highest potential (-1·2 bars). However, at 35 °C the last three fungi exhibited optimal growth at osmotic potentials of-10 to -20 bars. The ecological significance of these results is discussed in relation to cross-protection against the take-all fungi by the avirulent fungi.     

Distribution and sporulation phenology of myxomycetes in the Sonoran Desert of Arizona

All pith samples from 68 dead saguaro cacti in 3 plots and 11 isolated dead plants in Saguaro National Monument, Arizona, produced at least one species of myxomycete upon incubation at 20 or 30°C. Three species,Badhamia gracilis (Macbr.) Macbr.,Physarum straminipes Lister, andDidymium eremophilum M. Blackwell et Gilbertson, developed at high frequencies on the substrates in moist chamber culture.Perichaena corticalis (Batsch) Rost, andProtophysarum phloiogenum M. Blackwell et Alexopoulos were also present. Although previous literature reports [9] indicated that Myxomycetes grow best at low pH, these species all tolerated substrates of pH 8.7–10.4.Didymium eremophilum andP. phloiogenum had peaks in sporulation within 6 days; other species were slower. There was no difference in time of sporulation ofB. gracilis orD. eremophilum at 20 and 30°C; however, sporulation ofP. straminipes was significantly later at 30°C. Reduced spore germination and slower buildup of critically sized amoebal populations ofP. straminipes at 30°C may be a factor.     

Heat-stability of peroxidase in mycelia of some toxigenic and nontoxigenic Aspergilli and Penicillia

Seven-day-old mycelia from 19 cultures of Aspergillus and 12 cultures of Penicillium were heated to 50, 60, 65, 70, 75, 80, 85, 90 or 95 C for no more than min, and tested for residual peroxidase. The peroxidase from all aspergilli survived heating at 50 through 80 C. Peroxidase from toxigenic strains of Aspergillus flavus, Aspergillus parasiticus and Aspergillus ochraceus survived heating at 85 C and often at 90 C, whereas peroxidase from nontoxigenic strains of A. flavus was inactivated at 90 C and markedly reduced in activity at 85 C. Peroxidase from all penicillia survived heating at all temperatures through 80 C, although the activity of several cultures was reduced at 80 C. Peroxidase activity in mycelia of two strains of Penicillium cyclopium and one of Penicillium puberulum failed to survive heating at 85 C. One strain each of Penicillium roqueforti and Penicillium viridicatum exhibited some peroxidase activity after heating at 90 C, whereas the peroxidase of all other penicillia was inactivated at this temperature.     

The impact of cropping on wild populations of Saguinus mystax and Saguinus fuscicollis in Peru

A transect census technique was used to estimate the population densities of Saguinus mystax and Saguinus fuscicollis at two sites in Peru. Cropping of these two species had occurred five years before the census at one site and two years before at the other. The populations of S. mystax at both sites had recovered completely from cropping, and the relationship between S. mystax and S. fuscicollis had not been altered at one site and had been reversed in favor of S. mystax at the other.     

Distribution of Plectidae (Nematoda: Araeolaimida) in pasture soils

Abstract

Across 88 sites 9 species were found, with Anaplectus granulosus at 56 sites, Plectus parietinus at 47, P. longicaudatus at 30, P. parvus at 15, P. cirratus and Wilsonema otophorum at 11, P. armatus and A. porosus at 4, and Tylocephalus auriculatus at 1 site. A key to Anaplectus males is given. For nine sites mean length of female A. granulosus is negatively correlated with mean annual air temperature. The most diverse fauna comprised six species in Kaitoke silt loam; it appears that faunal diversity increases with higher rainfall. Species apparently coexist through separation in size and time. Tylocephalus was only found in soils with a thermic soil temperature regime.     

Effect of temperature on growth of some avirulent fungi and cross-protection against the wheat take-all fungus

The linear growth rates of Gaeumannomyces graminis var. graminis, G. graminis var. tritici, Phialophora radicicola var. graminicola and a lobed hyphopodiate Phialophora sp. were studied on agar at various temperatures between 5 and 30 °C and on wheat roots at two temperature regimes (12 h at 7°/12 h at 13 °C and 12 h at 17°/12 h at 23 °C). On agar at 30 °C, the isolates of G. graminis graminis grew faster than those of G. graminis tritici and Phialophora sp. but three isolates of G. g. graminis grew more slowly than the other two fungi at 5 and 10 °C. Two other isolates of G. g. graminis were cold-tolerant and had growth rates comparable to those of G. g. tritici and Phialophora sp. at 10 °C. The growth rates of Australian isolates of P. radicicola graminicolu were similar to that of a British isolate and were about a third to a half those of the other three fungi at most temperatures. The growth rates of the fungi on wheat roots at the low and high temperature regimes were correlated with the growth rates on agar at 10 and 20 °C respectively. The correlation was better at low temperatures r= 0.81) than at high temperatures (r = 0.62). Cross-protection experiments using two G. g. graminis isolates which grow poorly at temperatures below 15 °C and a cold-tolerant isolate each of G. g. graminis and Phialophora sp. showed that, while all four fungi protected wheat against take-all at high temperatures (17/23 °C) as evidenced by less severe disease and significantly greater dry weights, only the cold-tolerant fungi were effective at low temperatures (7/13 °C). The use of cold-tolerant isolates of avirulent fungi in field experiments may result in better protection in the early stages of wheat growth when Australian soil temperatures are mostly below 15 °C.     

Identification of Critical Stage for Disease Development and Biocontrol of Alternaria Blight of Indian Mustard (Brassica juncea)

Fungicides mancozeb and carbendazim caused 100% reduction in mycelial growth of Alternaria brassicae over control in vitro while 1% (w/v) aqueous bulb extract of Allium sativum and leaf extract of Acacia nilotica caused significant reductions. In dual culture, GR isolate of Trichoderma viride performed the best among the test isolates of Trichoderma, causing 81%, 82% reduction in mycelial growth of A. brassicae over control. Performance of isolates SI‐2, P and SI‐1 of T. viride were at par (P < 0.01) with that of GR isolate. Spraying of A. brassicae at different ages of the mustard host plant identified 75 days after sowing (d.a.s.) as the most critical age of the mustard plant for development of Alternaria blight severity on the crop with 45 d.a.s. being the next most important one. Mancozeb was the best among all the treatments, resulting in the lowest disease severity on leaves of mustard at both Sewar and Ludhavai as also the lowest A‐value (area under disease progress curve). Performance of bulb extract of A. sativum in checking the disease severity on leaves and pods was at par (P < 0.05) with mancozeb. The GR isolate of T. viride was at par with mancozeb in checking blight severity on mustard leaves at Sewar while performance of the bioagent was significantly (P < 0.05) inferior to the chemical fungicide at Ludhavai. Performance of the bioagent isolate GR of T. viride in checking the disease severity on pods was at par (P < 0.05) with mancozeb at both Sewar and Ludhavai, the treatment recording the lowest A‐value on pods. While application of bulb extract of A. sativum resulted in highest seed yield at Sewar in 2001–2002, the bioagent isolate GR of T. viride did so at Ludhavai, both the treatments being at par (P < 0.05) with mancozeb and significantly higher than control. Application of bulb extract of A. sativum at 45 and 75 d.a.s. resulted in lowest blight severity on leaves and pods as also in highest seed yield among the different single and combination of treatments. Although disease severity in the treatment was at par (P < 0.05) with that in mancozeb, application of the plant extract at the two stages of crop growth resulted in significantly higher seed yield compared with the two applications of the chemical fungicide. However, application of the treatments singly only at 75 d.a.s., GR isolate of T. viride at 45 and 75 d.a.s., A. sativum 45 d.a.s. + T. viride 75 d.a.s., and T. viride 45 d.a.s. + A. sativum 75 d.a.s. resulted in seed yield at par (P < 0.05) with application of bulb extract of A. sativum at 45 and 75 d.a.s.     

Alteration of low-temperature susceptibility of the cyanobacterium Synechococcus sp. PCC 7002 by genetic manipulation of membrane lipid unsaturation

Cyanobacteria acclimate to low temperature by desaturating their membrane lipids. Mutant strains of Synechococcus sp. PCC 7002 containing insertionally inactivated desA (Δ12 acyl-lipid desaturase) and desB (ω3 acyl-lipid desaturase) genes were produced, and their low-temperature susceptibility was characterized. The desA mutant synthesized no linoleic acid or α-linolenic acid, and the desB mutant did not produce α-linolenic acid. The desA mutant grew more slowly than the wild-type at 22° C and could not grow at 15° C. The desB mutant could not continuously grow at 15° C, although no observable phenotype appeared at higher temperatures. It has been shown that expression of the desA gene occurs at 38° C and is up-regulated at 22° C, and that the desB gene is only expressed at 22° C. These results indicate that the expression of the desA and desB genes occurs at higher temperatures than those at which a significant decline in physiological activities is caused by the absence of their products. The temperature dependency of photosynthesis was not affected by these mutations. Since chlorosis and inability to grow at 15° C with nitrate was suppressed by the substitution of urea as a nitrogen source, it is very likely that the chilling susceptibility of the desaturase mutants is attributable to nutrient limitation. Received: 24 April 1997 / Accepted: 5 August 1997     

Inoculation of containerized Pseudotsuga menziesii and Pinus pinaster seedlings with spores of five species of ectomycorrhizal fungi

 Container-grown Pseudotsuga menziesii and Pinus pinaster seedlings were inoculated with water suspensions of spores of five ectomycorrhizal fungi commonly found in northeastern Spain. Pseudotsuga menziesii seedlings were inoculated with basidiospores of Melanogaster ambiguus, or Rhizopogon subareolatus, or with ascospores of Tuber maculatum. Pinus pinaster seedlings were inoculated with basidiospores of Melanogaster ambiguus, Rhizopogon roseolus or Scleroderma citrinum. The spore concentrations were 10²–10⁷ spores per seedling for Melanogaster ambiguus (in Pseu dotsuga menziesii) and Rhizopogon subareolatus, 10³–10⁷ for Melanogaster ambiguus (in Pinus pinaster), Rhizopogon roseolus, and Scleroderma citrinum, and 10²–10⁴ for Tuber maculatum. Melanogaster ambiguus colonized more short roots in a larger proportion of plants at 10⁷ spores per seedling than at any other rate. The highest colonization by Rhizopogon subareolatus was obtained at 10⁴ spores per seedling and higher, and all inoculated plants became infected at 10⁶ spores per seedling and higher. Tuber maculatum colonized a high percentage of short roots at all rates tested; the proportion of infected plants was over 80% at 10³–10⁴ spores per plant, decreasing to 50% at 10² spores per plant. Rhizopogon roseolus colonized the highest number of short roots on nearly all the inoculated plants when applied at 10⁵ spores per seedling and higher. Scleroderma citrinum colonized a high percentage of short roots on all inoculated plants when applied at 10⁵ spores per seedling and higher. The abundance of sporocarps of Melanogaster ambiguus, Rhizopogon subareolatus, R hizopogon roseolus and Scleroderma citrinum and their colonization ability at relatively low rates allows these spores to be used as ectomycorrhizal inocula on a large scale. Accepted: 27 February 1996     

Genetic regulation of developmental phases in winter wheat

The orderly development of winter wheat through its life cycle can be marked at three stages: stem elongation, heading date, and physiological maturity. The duration of a developmental phase between two stages is important in yield component generation. In this study the three developmental stages were characterized and 350 markers were mapped in a population of recombinant inbred lines (RILs) generated from a cross between two winter wheat cultivars (‘Jagger’ and ‘2174’). Three major QTLs were found to control variation in developmental process, and each of them was tightly associated with a known flowering gene, VRN-A1 on chromosome 5A, PPD-D1 on chromosome 2D, and VRN-D3 on chromosome 7D. The average contribution of the gene marker for each QTL to the total phenotypic variation (R ²) was evaluated over 3 years. The effect of VRN-A1 ranged from 21.5% at stem elongation to 17.4% at physiological maturity. The effect of PPD-D1 was minor (6.7%) at stem elongation but increased to 29.7% at heading and 20.1% at physiological maturity. The effect of VRN-D3 was not detected at stem elongation but increased to 14.6% at heading and to 20.5% at physiological maturity. Hence, the VRN-A1 locus, the PPD-D1 locus, and the VRN-D3 locus had greatest impact on development at stem elongation, heading date, and physiological maturity, respectively. Whereas the Jagger VRN-A1 and VRN-D3 alleles accelerated development, the Jagger PPD-D1 allele delayed the developmental process due to its sensitivity to photoperiod. Our findings suggest that through the appropriate combination of alleles at these three loci one would be able to regulate the various developmental phases to accommodate different agricultural needs.     

The control of allelic recombination at histidine loci in Neurospora crassa

The gene rec-1⁺ which reduces allelic recombination at the his-1 locus by a factor of between 15 and 30 has no effect upon allelic recombination at the his-2, his-3, his-5, his-6 and his-7 loci. Other genes controlling recombination at two of these loci, namely rec-x at his-2 and rec-w at his-3, have been found. There is a strong possibility that rec-x may be identical with rec-3, so far known to regulate recombination only at the am-1 locus. It is probable that the stocks used all carry a rec⁺ gene which regulates recombination at the his-6 locus, since all prototroph frequencies are low, but no regulatory gene active at the his-5 and his-7 loci.     

Decay of Sclerotia of Botrytis cinerea by Trichoderma spp. at Low Temperatures

In vitro, tests were conducted at 10°C and 5°C against sclerotia of Botrytis cinerea with 58 isolates of Trichoderma spp., highly antagonistic at 24°C but differing in their cold tolerance. Some isolates macerated and colonized sclerotia even at 5 °C. With 19 isolates of Trichoderma spp. less than 10 % of the sclerotia remained viable after 42 d at 5 °C. Conidia ol some Trichoderma spp. germinated at 5 °C within a few days and reached germination rates higher than 80 %. It seems to be feasible to use selected isolates of Trichoderma spp. for biological control of sclerotia of ß. cinerea also during the colder season.     

Some effects of the nematodes Ditylenchus myceliophagus and Aphelenchoides composticola on the yield of the cultivated mushroom

The addition of one, ten and fifty Aphelenchoides composticola per ioo g compost at spawning reduced the total yield of sporophores by 26%, 30% and 42% respectively (P= 0·01), demonstrating a significant regression (P= 0·05) of yield on inoculum concentration. In pots inoculated at spawning with ten and fifty A. composticola per 100 g compost, cropping ceased after 12 weeks. The addition of twenty, 100 and 300 Ditylenchus myceliophagus at casing reduced the total yield of sporophores by 50%, 68% and 75 % respectively (P= 0·01). Cropping did not occur in pots inoculated at spawning, but continued for 9 weeks in pots inoculated at casing. The yield from pots inoculated at casing with either nematode was significantly greater (P= 0·05) than that from pots inoculated at spawning. When inoculated at spawning, peak populations of D. myceliophagus and A. composticola were reached 7 and 13 weeks, respectively, after spawning. Then the numbers present were unrelated to the number in the inocula.     

Haplotypic variation of the transporter associated with antigen processing (TAP) genes and their extension of HLA class II region haplotypes

Stable cell surface presentation of HLA class I molecules requires active transport of antigenic peptides across the endoplasmic reticulum by products of two genes, TAP1 and TAP2, which map in the major histocompatibility complex class II region. Alleles of each gene are derived from a combination of variable sitesaat each locus. In this study, TAP1 and TAP2 alleles were identified in homozygous typing cell (HTC) lines, allowing resolution of specific haplotypes in conjunction with the highly polymorphic HLA class II region haplotypes. Three alleles at each TAP locus were found from which eight haplotypes could be assigned. Determination of TAP1 and TAP2 alleles in cell lines homozygous at DR, DQ, and DP created eight additional haplotypes beyond the number observed with these class II genes alone. Complete analysis of DR, DQ, TAP, and DP genotypes in 66 HTCs resulted in the following groups: 1) 46 homozygotes; 2) nine homozygous at DR, DQ, and TAP, but heterozygous at DP; 3) four homozygous at DR, DQ, and DP, but heterozygous at one or both TAP genes; 4) four homozygous at DR and DQ, but heterozygous at TAP and DP; and 5) three complex genotypes heterozygous at DP, TAP, and at least one of DQA1, DQB1, or DRB1 loci. TAP1 and TAP2 genes map in an area of frequent recombination. TAP alleles were determined in five DQB1, DPB1 recombinant individuals, three of which were informative. Recombination was found between DQB1 and the TAP loci in two individuals and between TAP and DPB1 in the other individual.