Catenaria Anguillulae Research Articles

The inner mechanics of rhodopsin guanylyl cyclase during cGMP-formation revealed by real-time FTIR spectroscopy.

Enzymerhodopsins represent a recently discovered class of rhodopsins which includes histidine kinase rhodopsin, rhodopsin phosphodiesterases, and rhodopsin guanylyl cyclases (RGCs). The regulatory influence of the rhodopsin domain on the enzyme activity is only partially understood and holds the key for a deeper understanding of intra-molecular signaling pathways. Here, we present a UV-Vis and FTIR study about the light-induced dynamics of a RGC from the fungus Catenaria anguillulae, which provides insights into the catalytic process. After the spectroscopic characterization of the late rhodopsin photoproducts, we analyzed truncated variants and revealed the involvement of the cytosolic N-terminus in the structural rearrangements upon photo-activation of the protein. We tracked the catalytic reaction of RGC and the free GC domain independently by UV-light induced release of GTP from the photolabile NPE-GTP substrate. Our results show substrate binding to the dark-adapted RGC and GC alike and reveal differences between the constructs attributable to the regulatory influence of the rhodopsin on the conformation of the binding pocket. By monitoring the phosphate rearrangement during cGMP and pyrophosphate formation in light-activated RGC, we were able to confirm the M state as the active state of the protein. The described setup and experimental design enable real-time monitoring of substrate turnover in light-activated enzymes on a molecular scale, thus opening the pathway to a deeper understanding of enzyme activity and protein-protein interactions.

Absorption and Emission Spectroscopic Investigation of Thermal Dynamics and Photo-Dynamics of the Rhodopsin Domain of the Rhodopsin-Guanylyl Cyclase from the Nematophagous Fungus Catenaria anguillulae.

The rhodopsin-guanylyl cyclase from the nematophagous fungus Catenaria anguillulae belongs to a recently discovered class of enzymerhodopsins and may find application as a tool in optogenetics. Here the rhodopsin domain CaRh of the rhodopsin-guanylyl cyclase from Catenaria anguillulae was studied by absorption and emission spectroscopic methods. The absorption cross-section spectrum and excitation wavelength dependent fluorescence quantum distributions of CaRh samples were determined (first absorption band in the green spectral region). The thermal stability of CaRh was studied by long-time attenuation measurements at room temperature (20.5 °C) and refrigerator temperature of 3.5 °C. The apparent melting temperature of CaRh was determined by stepwise sample heating up and cooling down (obtained apparent melting temperature: 62 ± 2 °C). The photocycle dynamics of CaRh was investigated by sample excitation to the first inhomogeneous absorption band of the CaRhda dark-adapted state around 590 nm (long-wavelength tail), 530 nm (central region) and 470 nm (short-wavelength tail) and following the absorption spectra development during exposure and after exposure (time resolution 0.0125 s). The original protonated retinal Schiff base PRSBall-trans in CaRhda photo-converted reversibly to protonated retinal Schiff base PRSBall-trans,la1 with restructured surroundings (CaRhla1 light-adapted state, slightly blue-shifted and broadened first absorption band, recovery to CaRhda with time constant of 0.8 s) and deprotonated retinal Schiff base RSB13-cis (CaRhla2 light-adapted state, first absorption band in violet to near ultraviolet spectral region, recovery to CaRhda with time constant of 0.35 s). Long-time light exposure of light-adapted CaRhla1 around 590, 530 and 470 nm caused low-efficient irreversible degradation to photoproducts CaRhprod. Schemes of the primary photocycle dynamics of CaRhda and the secondary photocycle dynamics of CaRhla1 are developed.

Fungi and fungus-like organisms growing in selected lotic oxbow lakes and tributaries of the Narew River

Abstract Mycological and hydrochemical research was conducted in two different types of reservoirs connected with the Narew riverbed (three tributaries and three lotic oxbow lakes) in two growing seasons. The obtained results seem to indicate that more favorable conditions for the development of the analyzed microorganisms prevailed in the studied tributaries of the Narew. A total of 36 species of fungi and fungus-like organisms were identified in these tributaries in spring and 35 in autumn, while respectively 32 and 26 species in the lotic oxbow lakes. Six taxa not identified in the oxbow lakes were found only in the tributaries of the river. They were: Alternaria alternata, Allomyces moniliformis, Catenaria anguillulae, Leptomitus lacteus, Rhipidium parthenosporum and Saprolegnia diclina. On the other hand, only two species occurred only in the oxbow lakes (not recorded in tributaries) (i.e. Catenophlyctis variabilis and Rhizophlyctis rosea). The differences observed in the microfungi species composition in the studied ecosystems are associated, among others, with the time of the year and physicochemical properties of the water. Hydrochemical parameters such as temperature, pH, Mg, N-NH3, N-NO3, P-PO4 and suspended solids showed positive correlation, and sulfates, chlorides, Ca, Fe correlated negatively with the number of taxa observed.

Nematophagous fungi: Catenaria anguillulae and Dactylaria brochopaga from seed galls as potential biocontrol agents of Anguina tritici and Meloidogyne graminicola in wheat (Triticum aestivum L.)

During the course of our investigation on the selective isolation and in vitro pathogenicity tests of the nematode egg parasite and endoparasitic Catenaria anguillulae and the nematode-trapping fungus Dactylaria brochopaga against Anguina tritici, and Meloidogyne graminicola, the two biocontrol agents were also examined for their capabilities to colonize wheat seed gall and also to reduce the M. graminicola, and A. tritici in wheat (Triticum aestivum L.). Using seed galls as bait was found effective for isolating the soilborne natural colonizers of seed galls of wheat caused by A. tritici. Seed galls were found severely infested with cellulose decomposers as well as nematode trapping fungi i.e., Fusarium spp., Verticillium spp., Aspergillus spp., Penicillium spp. Arthrobotrys oligospora, Arthrobotrys superba, Arthrobotrys dactyloides, Arthrobotrys musiformis, D. brochopaga, Monacrosporium eudermatum, Stylopaga hadra, Paecilomyces spp., and C. anguillulae. Co-inoculation of D. brochopaga DBS-105, and C. anguillulae CAS101 significantly reduced the root knot and seed gall in wheat and increased the plant growth parameters including length, and dry weight of root and shoot as well as yield attributing characters like spike length; number of seed per spike, test weight etc. under greenhouse conditions as compared to pathogen challenged plants without any bioagents/chemical nematicide. These bioagents have the potential to enhance production of quality seeds of wheat being free from hazardous pesticides and thus, can further be developed into marketable formulations in order to promote eco-friendly and sustainable means of crop production.

Oil Cakes as Media for Growing Catenaria anguillulae Sorokin, a Facultative Endoparasite of Nematodes

Growth, morphology, visibility of sporangia and colony colour of 10 isolates of Catenaria anguillulae were compared on six media: linseed oil-cake agar, mustard oil-cake agar, neem oil-cake agar, beef extract agar, Emerson agar and YPSS agar with a view to selecting the best growth medium. In general, maximum radial growth of most of the isolates was recorded on linseed oil-cake agar medium, whereas neem oil-cake agar medium supported least growth of all the isolates of C. anguillulae. Linseed oil-cake agar medium also maintained the typical characters of the fungus and clear visibility of morphological details.

Techniques for selective isolation, semiquantification and rapid virulence testing of Catenaria anguillulae

Techniques for selective isolation, semiquantification and rapid virulence testing are described for Catenaria anguillulae, an important endoparasitic fungus of nematodes. Selective isolation was achieved by using second-stage juveniles of Anguina tritici as bait in soil aliquots for 48 h. Semiquantitative estimation of the population of the fungus was made by calculating the infection percentage of inoculated juveniles. Rapid virulence testing was done by using second-stage juveniles of Heterodera cajani, Meloidogyne incognita and A. tritici.

Orientated zoospore attachment and cyst germination in Catenaria anguillulae, a facultative endoparasite of nematodes

Zoospores of the nematode-parasitic Catenaria anguillulae (Chytridiomycota) were studied by videomicroscopy in sealed films of water on microscope slides in the presence or absence of freeze-inactivated nematodes ( Panagrellus redivivus ). Zoospores swam for more than 1 h at a mean velocity of 104 μm s -1 , interspersed with repeated phases (1–2 min) of amoeboid crawling on glass or nematode surfaces. They were attracted to and encysted near the mouth, excretory pore, and anus of nematodes, or eventually encysted at random on glass and nematode surfaces. The single posterior flagellum was immobile during amoeboid crawling but resumed rapid beating when the last pseudopodium was being retracted. Zoospores encysted by adhesion of the anterior of an amoeboid cell to a surface; then the cell posterior was raised above the anterior so that the flagellum projected perpendicular to the surface, and the flagellum was retracted by rotation of the cell contents. Cysts germinated within 20–60 min by a narrow germ-tube at the site of adhesion. The germ-tube grew a short distance, then formed an intercalary vesicle into which the cyst contents emptied by expansion of a cyst vacuole. In several cases the germ-tube penetrated a nematode and formed the vesicle inside the host. Rhizoids or assimilative hyphae developed from the vesicle or by growth of the germ-tube tip. An increasing proportion of zoospores that remained motile after 1 h in water films had a globose body in contrast to the normal elongated form. This seemed to be caused by damage during repeated transitions between the amoeboid and swimming phases, because pseudopodia sometimes remained firmly attached to a glass surface. C. anguillulae showed consistent orientation (polarity) of zoospore encystment and cyst germination. This parallels the behaviour of other zoosporic fungi or fungus-like organisms ( Plasmodiophora brassicae, Rozella allomycis, Pythium, Phytophthora and Saprolegnia spp.) suggesting that it is a common feature of zoosporic parasites. Surface-recognition for encystment by C. anguillulae was mediated by the zoospore soma, not the flagellum. In addition, we redefine the early development of C. anguillulae , including flagellar retraction by rotation of cell contents, non-specific adhesion of zoospores and cysts to surfaces, and evacuation of cyst contents into a vesicle from which further growth occurs.

Evaluation of Methods for Extraction of Nematodes and Endoparasitic Fungi From Soil

Six methods were tested for nematode extraction: the Seinhorst elutriator, Cobb's decanting and sieving, the Whitehead direct method (Whitehead tray), and centrifugal-flotation with silica (Ludox LS), sucrose and MgSO 4 , respectively. The most efficient methods for non-parasitic nematodes were centrifugal-flotation with silica, the Seinhorst elutriator and the Whitehead tray. Tylenchorhynchus spp. and total plant parasitic nematodes were recovered in largest numbers with the elutriator and the three centrifugation-flotation methods. The largest numbers of Pratylenchus crenatus were recovered with the Whitehead tray, while centrifugal-flotation with silica was superior for the trichodorids. Four species of endoparasitic nematophagous fungi (Catenaria anguillulae, Harposporium anguillulae, Nematoctonus leiosporus and Hirsutella rhossiliensis) were isolated from nematodes extracted with four of the six methods: the Seinhorst elutriator, the Whitehead tray, centrifugation with silica and centrifugation with sucrose. The largest numbers of infected nematodes were obtained with centrifugal-flotation with silica and the elutriation method. The smallest number of endoparasitic fungi were recovered by using Cobb's decanting and sieving and the Whitehead tray methods.

Fatty acids and sterols of selected hyphochytriomycetes and chytridiomycetes

The fatty acids and sterols of eight Chytridiomycetes and two Hyphochytriomycetes, and fatty acids of the Oomycete Pythium gracile, were analyzed by gas-liquid chromatography. In addition to the fatty acids anticipated for fungi, the two Hyphochytriomycetes ( Hyphochytrium catenoides and Rhizidiomyces apophysatus) and four of the Chytridiomycetes ( Catenaria anguillulae, Blastocladiella emersonii, Monoblepharella sp., and Allomyces macrogynus) contained arachidonic acid as a major fatty acid of the polar lipid fraction, and this fatty acid was detected as a minor component of Rhizophlyctis rosea and Spizellomyces punctatum. Eicosapentaenoic acid constituted 4.6% of the polar lipid fatty acids in Monoblepharella sp., and trace amounts were detected in several other species. Both the gamma (ω-6) and alpha (ω-3) isomers of linolenic acid were detected in all of the species analyzed. Cholesterol was the predominant (≥73%) sterol of B. emersonii, R. rosea, A. macrogynus, and Chytridium confervae, and a minor (<12%) component of C. anguillulae, and H. catenoides. The major sterols of the other species included lanosterol ( C. anguillulae, 45%), stigmasta-5,22-dien-3β-ol ( H. catenoides, 51%), 24-ethyl-cholesterol ( S. punctatum, 38%; H. catenoides, 17%; Monoblepharella sp., 70%; and R. apophysatus, 84%), 24-methyl-cholesterol ( H. catenoides, 23%; R. apophysatus, 14%; S. punctatum, 53%), and 24-methylene cholesterol ( Rhizophydium sphaerotheca, 51%). Neither ergosterol nor fucosterol was detected in any of the species studied.

Parasitism of Xiphinema Americanum and X. Rivesi By Catenaria Anguillulae and Other Zoosporic Fungi in Soil Solution, Baermann Funnels, or Soil

In dilute soil extract, Xiphinema rivesi was more susceptible than X. americanum to Catenaria anguillulae; the virulence of six isolates of C. anguillulae to Xiphinema also differed. When added to Baermann funnels, zoosporic fungi infected significant numbers of Xiphinema spp. but did not affect the number of nematodes extracted. In a greenhouse test, soil naturally infested with X. americanum and X. rivesi was amended with zoosporic fungi and planted with sudan grass. After 3 months, the zoosporic fungi had not reduced nematode numbers but infected significant numbers of Xiphinema in Baermann funnels; thus, the fungal inoculum persisted for 3 months in soil.

Parasitism of Phytophthora cinnamomi and P. parasitica spores by Catenaria anguillulae in a soil environment

Invasion of Phytophthora cinnamomi oospores, P. parasitica oospores, and/or P. parasitica chlamydospores by one or more fungal parasites was observed in seven of eight southern California soils tested. Catenaria anguillulae was isolated from invaded oospores of P. cinnamomi used as bait in a citrus soil. Oospores of P. cinnamomi and P. parasitica were invaded when tested in two-membered cultures with C. anguillulae in sterile soil extract.

Screening of Blastocladialean Fungi for Antibiotic Production by a Modified “Cross-Streak” Test

(1983). Screening of Blastocladialean Fungi for Antibiotic Production by a Modified “Cross-Streak” Test. Mycologia: Vol. 75, No. 5, pp. 909-913.

Fresh water chytrids from varanasi (India). IV. Some polycentric forms

In this paper five polycentric chytrids have been described, Nowakowskiella elegans, N. profusa, Polychytrium sp., Catenaria anguillulae and Hyphochytrium catenoides. Of the five species described, N. profusa and Polychytrium sp. are new records from India.

Ultrastructure of the formation of γ particles during zoosporogenesis in Allomyces macrogynus and Catenaria anguillulae

The sequence of intracellular transitions leading to the formation of γ particles during zoosporogenesis was examined by electron microscopy of synchronous cultures of Allomyces macrogynus and semisynchronous cultures of Catenaria anguillulae . In Allomyces the first identifiable progenitors of the γ matrix are 60-nm-diameter electron-opaque granules found within cisternae of rough ER. These particles appear during the first 30 minutes after the induction of sporogenesis. By the completion of papilla formation these “subunits” increase in number and size to form spherical structures ca. 133 nm in diameter. At the beginning of nuclear cap formation the 133-nm-diameter electron-opaque granules fuse to form larger spheres averaging 216 nm in diameter. These structures occur singly and in groups which fill the smooth-surface cisternae containing them. Toward the end of nuclear cap formation the granules fuse to form the 500-nm-diameter γ body. In Catenaria the first progenitors of γ particles are 45-nm-diameter electron-opaque granules with transparent centers that appear within swollen cisternae of tubular smooth ER. These granules form larger aggregates which fuse after cleavage to form the fully differentiated γ matrix. The γ particles of Catenaria are ca. 250 nm in diameter, which is smaller than the ca. 500-nm-diameter γ particles of Allomyces macrogynus and Blastocladiella emersonii .

Catenaria anguillulae in the mermithid nematode Romanomermis culicivorax

Disease epizootics in laboratory cultures of the mermithid nematode Romanomermis culicivorax were caused by a chytridiomycetous fungal parasite, Catenaria anguillulae. Techniques used for mass rearing the nematode provided ideal conditions for dispersal of zoospores and multiplication of the fungus; up to 90% of the postparasites of R. culicivorax were parasitized. The fungus was isolated and grown on yeast extract-soluble starch agar, and the effects of different temperature and pH regimes on the fungus were investigated as possible methods for prevention or control. A temperature suitable for mass rearing the nematodes but unsuitable for the fungus could not be found, as C. anguillulae had a broad temperature range. Adjustment of pH or a short period of chilling (0°C) were more promising control measures. At acid pH (<5), zoospore motility and germination and infection of postparasites were suppressed. The disease was controlled by rearing nematodes in water adjusted to a pH of 4.5.

Sulfur Source and Vitamin Requirements of the Aquatic Phycomycete, Catenaria Anguillulae

The requirements of the aquatic Phycomycete, Catenaria anguillulae Sorokin, were analyzed in liquid, shake cultures using a standardized zoospore inoculum. Growth was determined by measuring myceli...

Sulfur Source and Vitamin Requirements of the Aquatic Phycomycete, Catenaria anguillulae

SUMMARYThe requirements of the aquatic Phycomycete, Catenaria anguillulae Sorokin, were analyzed in liquid, shake cultures using a standardized zoospore inoculum. Growth was determined by measuring mycelial dry weight and rate of production of titratable acid.Catenaria required a reduced sulfur source and utilized DL- and L-methionine, DL-homocysteine, DL-cystathionine, L-cysteine, L-cystine and S-methyl-L-cysteine. The optimum concentration of L-methionine was between 50 and 100 ppm. Concentrations of 20 and 50 ppm D-methionine inhibited growth in the presence of 50 ppm D-methionine; whereas, concentrations of 5 and 10 ppm D-methionine were non-toxic. Methyl donors did not enhance the utilization of DL-homocysteine. DL-selenomethionine or DL-selenomethionine plus MgSO4 would not substitute for methionine. The isolate did not have a requirement for an external vitamin source.

The Phycomycete Catenaria anguillulae: Growth Requirements

SUMMARY: The physical factors and nitrogen requirements for the growth of the aquatic phycomycete Catenaria anguillulae in liquid shaken cultures from measured zoospore inocula were examined. Growth was determined by measuring mycelial dry weight and rate of titratable acid production. The optimum pH range for growth was pH 8.2 to 8.7. The toxicity of the pH indicators used was assessed. The optimum temperature for growth was 25°. The organism was highly aerobic. Inorganic nitrogen sources were not utilized. When organic nitrogen sources were supplied individually, L-aspartic acid, L-asparagine, L-glutamic acid, L-arginine, DL-citrulline and L-ornithine were utilized. Asparagine was the best single source. When the N sources were supplied as Difco vitamin-free Casamino acids, only lysine, methionine and arginine were utilized during the lag phase. During the more rapid phase of growth, all of the amino acids detected in the Casamino acids were utilized. When the vitamin-free Casamino acids were replaced by an equivalent amino acid mixture, the subsequent decrease in yield was not corrected by adding NaCl, oleic acid or stearic acid. The optimum concentrations of various N sources were determined. The medium finally evolved contained L-asparagine + L-lysine as N sources.

Factors Influencing Catenaria Anguillulae Infections in a Free-Living and a Plant-Parasitic Nematode

A phycomycetous fungus, Catenaria anguillulae, a parasite of phytonematodes, was isolated from greenhouse soil and cultured. Zoospores of the fungus were tested for virulence to the nematodes, Panagrellus redivivus and Ditylenchus dipsaci. A linear relationship was shown to exist between increasing numbers of zoospores and the incidence of the fungus disease in nematodes in vitro. The fungus developed more rapidly at 28° C than at the lower temperatures. D. dipsaci was less susceptible to attack from the fungus than P. redivivus. A pH of 9 and a low salt concentration favored the rapid development of the fungus in nematodes. Many more zoospores were required in sand and soil to achieve the same incidence of the disease than in liquid cultures. The tests indicated that this fungus isolate was not a very effective biological control agent.

Ultrastructure of Mitosis in the Aquatic Fungus Catenaria anguillulae

SUMMARYThe ultrastructure of mitosis in the zoosporangia of the water mold Catenaria anguillulae has been studied. The nuclear divisions prior to the formation of zoospores are mitotic. Centrioles are associated with but not connected to the spindle which is intranuclear. The nuclear membrane persists throughout the division process.It is suggested that anaphase separation of the daughter chromosomes is accomplished by the elongation of spindle tubules of the interzonal region. Telophase is marked by the rounding up of the daughter nuclei with the exclusion from the nucleus of a central, spindle-shaped structure which is then apparently broken down.