Leptomitus Lacteus Research Articles

(2902) Proposal to conserve the name Leptomitus with a conserved type (Leptomitales, Peronosporophyceae, Saprolegniophyta (Algae s.l.))

(2902) Leptomitus C. Agardh, Syst. Alg.: xxiii, 47 (‘49’). Mai–Sep 1824, nom. cons. prop. Typus: L. lacteus (Roth) C. Agardh (Conferva lactea Roth), typ. cons. prop. The former oomycete genus Leptomitus C. Agardh (Syst. Alg.: xxiii, 47 [‘49’]. 1824) forms one of the most important phylads of the class Peronosporophyceae M.W. Dick (Stramin. Fungi: 289. 2001, as ‘Peronosporomycetes’), and commonly constitutes a distinct family Leptomitaceae Kütz. (Phycol. General.: 147. 1843, as ‘Leptomiteae’) and order Leptomitales Kanouse (in Amer. J. Bot. 14: 295. 1927) (Sparrow, Aquatic Phycomyc.: 871–873. 1960; Kussakin & Drozdov, Filema Organich. Mira 2: 251. 1998; Riethmüller & al. in Canad. J. Bot. 77: 1795. 2000 (‘1999’); Frey in Engler, Syllabus, ed. 13, 1(1): 100. 2012; Marano & al. in Jones & Pang, Mar. Fungi: 190. 2012; Beakes & Thines in Archibald & al., Handb. Protists: 41. 2016). These microorganisms are currently classified outside the Kingdom Fungi, and in this connection, they are placed within the crown of algal phylads of chromalveolates (Adl & al. in J. Eukar. Microbiol. 59: 454. 2012, 66: 40. 2018; Beakes & al. in Protoplasma 249: 3–19. 2012, in McLaughlin & Spatafora, Mycota 7A: 39–97. 2014; Wijayawardene & al. in Mycosphere 11: 1060–1456. 2020), generally treated as “ambiregnal” botanical and protozoological taxa at the rank of phylum Saprolegniophyta Karpov (Sist. Protistov: 120. 1990, as ‘Saprolegnia’), pro zool. phyl. (Kussakin & Drozdov, l.c.: 246, as ‘Saprolegniophyles’) or subphylum Peronosporophytina M.W. Dick (l.c.: 288, as ‘Peronosporomycotina’) [terminations modified to reflect treatment under the ICN (Turland & al. in Regnum Veg. 159. 2018: Art. 45.1) and treatment as Algae and not Fungi]. The species circumscription of the genus is variable from 9 to 10 species to monotypic (Sparrow, l.c.; Dick, l.c.). Numerous binomials (more than 20) are also ill-known, being schematically described in the 19th century, but are mostly unidentifiable and remain nomina dubiosa. Unfortunately, when initially proposed, the genus Leptomitus inadmissibly included the original types of two (sic!) previously validly published oomycete generic names, Achlya Nees (in Nova Acta Phys.-Med. Acad. Caes. Leop.-Carol. Nat. Cur. 11: 514. 1823: A. prolifera Nees) and Saprolegnia Nees (in Nova Acta Phys.-Med. Acad. Caes. Leop.-Carol. Nat. Cur. 11: 513. 1823: S. molluscorum Nees, nom. illeg. [Conferva ferax Gruith. ≡ S. ferax (Gruith.) Kütz.]). Achlya and Saprolegnia are now considered to be distinct, well-circumscribed genera and are in current use (Dick, l.c.; Beakes & Thines, l.c.). So, Leptomitus is a nomenclaturally superfluous and illegitimate generic name since when established it included types of previously validly published generic names. To overcome this nomenclatural illegitimacy, it is necessary to conserve the generic name with an established element as type (Leptomitus lacteus (Roth) C. Agardh [Conferva lactea Roth]) to allow its further use in botanical systematics and to maintain the nomenclatural stability and established custom in the formerly oomycetous nomenclature. Since due to some tradition to treat oomycetes as straminipilous Protista that continues, though archaically, to the present (Karpov, l.c. 1990, Sist. Protistov, ed. 3: 168. 2000; Kussakin & Drozdov, l.c.; Beakes & Thines, l.c), the same proposal will be submitted to the International Commission on Zoological Nomenclature asking for analogous action to legitimize Leptomitus as a genus in (proto)zoological nomenclature (ICZN) for those researchers who will permissibly continue to treat these microorganisms as protists (so-called “ambiregnal” organisms). ABD, https://orcid.org/0000-0003-0089-5919 It is a pleasure to thank Valentina Bublik (Fundamental Botanical Library of the National Institute of Carpology, Moscow) for bibliographic assistance.

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.

English

The authors investigated the growth of hydromycobiota on the eggs of rainbow trout (Oncorhynchus mykiss) in waters of different trophicity. Of the O. mykiss eggs that were investigated, 16.6% were found to be infected by mycotal species. Thirty mycotal species were found on eggs obtained from adult female representatives. Achlya polyandra, A. radiosa, Aphanomyces laevis, Leptomitus lacteus, Saprolegnia ferax and Saprolegnia parasitica belonged to the species that were most commonly encountered. Aphanomyces frigidophilus, Candida albicans and Zoopage phanera were rarely found in salmonid fishes. Amino acid, carbohydrate and urease tests were used, and all analyses of species from the Achlya, Aphanomyces, Leptolegnia, Pythium and Saprolegnia genera showed that they assimilate glucose and starch. However, they did not assimilate glycine, leucine, lysine, ornithine, and arabinose. Urease was assimilated only by species from the Leptolegnia, Pythium and Saprolegnia genera. Key words: Oncorhynchus mykiss, rainbow trout, eggs, mycotal species, infection, hydrochemistry.

English

The authors investigated the growth of straminipiles fungi on the alevins of Nile tilapia (Oreochromis niloticus niloticus L.) in water from eight limnologically and trophically different water bodies. Twenty-seven species were recorded. The largest number of species occurred on alevins in water from the Biala River and Fosa Pond (more biogenic), and the fewest in water from Dojlidy Pond and Lake Blizno (poor in biogenesis). The most commonly encountered species on Nile tilapia alevins were Saprolegnia parasitica, Saprolegnia ferax, Achlya polyandra, Achlya  oligocantha, Achlya prolifera, Leptomitus lacteus, and Pythium diclinum. Amino acid, carbohydrate, and urease tests were used.   Key words: Oreochromis niloticus, alevins, straminipiles infections, hydrochemistry.

Studies on toxicity of selected Oomycetes

The MTT test is used to determine the cytotoxicity of species: <em>Achlya americana, A. caroliniana, Leptomitus lacteus, Saprolegnia ferax</em> and <em>S. lapponica</em>, which occurred in Lake Sitno in the Drawieński National Park (W Poland). It was stated that among five examined species of zoosporic fungi only one of them <em>A. caroliniana</em>, does not show cytotoxic effect. Low and mean toxicity of other tested water FLO, however, combined with the large-scale character of their appearance shows, that they can create serious threat for the spawn, fry, fish as well as the other organisms (including invertebrates) existing in water.

English

The straminipiles (Oomycota), lineage of fungus-like eukaryotic microorganism, growing on the eggs of an African catfish, Clarias gariepinus, in water of different trophicity in Poland have been investigated. Twenty-one (21) species were recorded. The largest number of species occurred on eggs in water from River Biala and Pond Fosa (more biogenic), the smallest in water from River Suprasl and Pond Dojlidy (poor in biogenes). The most commonly encountered species on the C. gariepinus eggs were: Saprolegnia parasitica, Achlya polyandra, A. oblongata, A. prolifera, Aphanomyces frigidophilus, S. ferax and Leptomitus lacteus. Amino-acid, carbohydrate and urease tests were used. 11.4% of C. gariepinus eggs investigated were found to be infected by Straminipiles species.   Key words: Clarias gariepinus, eggs, straminipiles (Oomycota), infections, hydrochemistry

Metabolism and ecology of the water mould, Leptomitus lacteus (Oomycota), blooming in winter in a Nova Scotia stream

The water mould Leptomitus lacteus bloomed in a small stream in northern Nova Scotia, Canada, for at least four months from December through March when water temperatures were near 0 °C and the stream was fre- quently ice-covered. The bloom occupied much of the substratum along 1.5 km of stream below the effl uent outfall from a composting facility. A true fungus, Saprochaete saccharophila, was a minor component of the bloom. L. lacteus colonies appeared robust against freezing and regrew quickly after scouring fl oods. L. lacteus preferred rif- fl es and fast-fl owing water, evidently because of a high oxygen requirement. In mid-winter, the standing crop of L. lacteus approached 2.5 kg m -2 fresh mass, or 2000 kg along the whole length of stream. The bloom ended abruptly in April when water temperatures rose above 5 °C. In the laboratory, clumps of L. lacteus demonstrated vigorous oxygen consumption near 0 °C. Oxidative metabolism was largely confi ned to the outer 6 mm of the colonies, interior to which (O2) declined precipitously. Evidence suggests that L. lacteus blooms in winter to take advantage of a rich food source and high (O2) while avoiding competition. Similar blooms of L. lacteus elsewhere may be overlooked because winter weather and ice cover discourage investigations.

The seasonal occurrence of the sewage fungus Leptomitus lacteus (Roth) C. Agardh in stagnant and running waters of different water chemistry of Hesse and Thuringia, Germany

AbstractWe compared the seasonal occurrence of Leptomitus lacteus (Roth) C. Agardh (Oomycetes, Leptomitales) in freshwater samples from autumn 2003 to summer 2004. For this purpose, we analysed 42 different water samples of running waters from Hesse and Thuringia and additionally of stagnant waters and of a spring from Hesse. For isolating L. lacteus, the baiting technique was used. The simultaneous limnochemical characterisation of the examined waters resulted in information on the trophic status of the lakes and the water quality classification of some rivers. L. lacteus occurred in all three types of waters examined. Based on the number of samples in which it occurred, L. lacteus seems to prefer rivers rather than stagnant waters. L. lacteus could be isolated during the whole year. Nevertheless, most isolates were obtained in winter. Hence, a preference for growth and propagation in winter is postulated.

Five Serbian reservoirs contain different fungal propagules

This paper presents results of a mycological survey conducted in five large reservoirs in Serbia (Sjenica, Barje, Garaši, Meðuvršje and Ovčar-Kablar) that have different hydrobiological and production characteristics. The sampling was conducted in March, June, August and October 2002. Quantitative analysis of fungal communities showed that the average number of colony-forming units in these reservoirs was 1966–5682/L of water. The highest number of CFUs was found in the α-mesosaprobic (Class III) Ovčar-Kablar Reservoir and the lowest was in the oligosaprobic (Class I) Sjenica Reservoir. CFUs were higher in samples taken near lake bottoms and in littoral zones rich with macrovegetation than in the middle depths. In these reservoirs 48 species were identified from 720 isolates. The dominant genera were Penicillium, Aspergillus, Cladosporium, Fusarium, Rhizopus, Mucor, Phoma and Verticillium. The autochthonous aquatic fungal community comprised these species: Achlya americana, A. diffusa, A. racemosa, Dictyuchus sterile, Isoachlya toruloides, Leptomitus lacteus, Pythium ultimum, Saprolegnia ferax, S. hypogyna and S. monica. My results indicate that aquatic fungi on the whole are better represented in lakes with a higher trophic status.

The Fungal Community of Lake Sjenica, Serbia

ABSTRACT From water samples collected throughout the year from Lake Sjenica, four hundred and eighty cultures of filamentous fungi (Zygomycotina, Ascomycotina, and Deuteromycotina) were isolated. These comprised 44 species from 16 genera, the dominant of which were Penicillium and Aspergillus. The average number of spores per liter of water was relatively high, with maximum of 7,050 in March and a minimum of 451 in July. The number of spores and the number of isolates were both greatest in samples taken in March and September. Some differences in vertical distribution were present. The community of autochthonous aquatic fungi was made up of the species Achlya americana, A. racemosa, Dictyuchus sterile, Leptomitus lacteus, Pythium ultimum, Saprolegnia ferax, S. hypogyna, and S. monica. No regularity was discernible in the distribution of these fungi.

The biosynthesis of oxylipins of linoleic and arachidonic acids by the sewage fungus Leptomitus lacteus, including the identification of 8R-Hydroxy-9Z,12Z-octadecadienoic acid.

When the sewage fungus Leptomitus lacteus was grown in liquid culture aerobically and then transferred to medium containing long-chain fatty acids, it produced a number of oxygenated fatty acids. From linoleic acid (18:2n-6), the major metabolite produced was R-8-hydroxy-9Z,12Z-octadecadienoic acid (8R-HODE), with additional quantities of 8,11-di-HODE, 11,16-di-HODE, and 11,17-di-HODE. Other fatty acid derivatives identified included 7-HODE, 10-HODE, and 13-hydroxy-octadecamonoenoic acid. Arachidonic acid (20:4n-6) was metabolized primarily to 18- and 19-hydroxy-eicosatetraenoic acids (18- and 19-HETE) also as R enantiomers, along with smaller quantities of 17-HETE, 9-HETE, 14,15-dihydroxy-eicosatrienoic acid and 11,12,19-trihydroxy-eicosatrienoic acid. The oxygenated products of long-chain fatty acids, in particular the biosynthesis of 8R-HODE, a compound classified as a precocious sporulation inducer, were similar to those produced by an unrelated fungal species in the Ascomycota, the take-all fungus Gaeumannomyces graminis. As in G. graminis, the biotransformation of linoleate to 8R-HODE was not significantly inhibited by exposure of the organism to CO. This indicated that the enzyme responsible for 8R-HODE biosynthesis in Leptomitus could be similar to that of G. graminis; yet we did not detect 7,8-di-HODE as a product of 18:2n-6 metabolism as in G. graminis. CO did inhibit the biosynthesis of 14,15-di-HETE, 18-HETE, and 19-HETE in L. lacteus, which suggested the involvement of a cytochrome P450-type monooxygenase. The biosynthesis of 8R-HODE from 18:2n-6 was found to occur in certain cell lysates, specifically in low speed (15,000 x g) supernatant, following cell disruption.

Occurrence of the sewage fungus Leptomitus lacteus, a necrotroph on perch ( Perca fluviatilis), in Windermere

Spore assays of the sewage fungus, Leptomitus lacteus were made in Windermere. The assays suggested that at the lake margin there was one spore in about 1430 ml of water. Spores were fewer at the lake centre, one in about 10 l of water in one assay and less than 1 in 21 l of water in another assay. This disparity in assays between lake margin and lake centre indicates that Leptomitus lacteus is active in decomposition processes in the lake littoral; other observations show that both plant and animal materials can serve as substrata.

Hyphal Wall Chemistry of Leptomitus Lacteus

Isolated hyphal walls of the oomycete, Leptomitus lacteus, contain approximately 74% 3B-glucans, the major portion of which is apparently composed of (1-->3)and (1 -> 6)-linked glucosyl residues. Cellulose occurs as cellulose I of relatively low crystallinity and constitutes approximately 6.2-7.5% of wall weight. Hexosamine polymers account for 14.5% of wall weight. The major portion of the hexosamine fraction (13.8%) is insoluble and assumed to be present as chitin. The qualitative presence of chitin was demonstrated by X-ray diffraction analysis. The protein content of 3.6% is made up of a broad assortment of the common amino acids plus low levels of hydroxyproline. Additionally, small amounts of readily extracted and bound lipids (1.8% total) and ash (0.3%) are present. In general, the wall composition of L. lacteus is quite similar to that of the related fungus, Apodachlya sp. and this work supports the assertion that walls of leptomitaceous species are chitinous in contrast with walls of rhipidiaceous species which apparently are not.

Epidermal lesions and fungal infection on the perch, Perca fluviatilis L., in Windermere

An account is given of the histological changes associated with epidermal lesions on the Windermere perch, Perca fluviatilis L., between the months of January and March, 1976. During the later stages of the development of the lesions an apparent succession of fungal colonization was observed. A total of five genera of fungi were identified with Leptomitus lacteus appearing early in the infection and Achlya tending to dominate the more advanced lesions. The initial cause of the lesions has not been identified but the possibility of Argulus damage is discussed.

The Growth of Micromycetes in Activated Sludge Media

AbstractToday already numerous micromycetes are a recognized part of the biocenosis of growth in receiving waters strongly polluted by organically rich waste waters and of growth on biofilter media surfaces. The principal representatives are some Deuteromycetes, Mucorales and Saccharomycetaceae, whereas the so‐called true aquatic fungi (Oomycetes) with the exception of Leptomitus lacteus are practically absent. The growth of micromycetes in activated sludge remains still an unanswered question. Generally, the filaments in the activated sludge are ascribed to filamentous bacteria and as long as fungi were isolated from activated sludge their presence has been reported only in the form of spores.The nitrogen deficiency with regard to carbon present in the waste water is considered as one of the factors enhancing the development of fungi in the activated sludge. In a series of 13 tests carried out on laboratory‐scale batch models using synthetic waste water, where the carbon source was glucose and the nitrogen source was (a) sodium nitrate, (b) ammonium sulphate, and (c) peptone, the fungal growth was studied in different models with the BOD:N ratio varying from 20 to 1000. The models were seeded with thickened activated sludge from the municipal sewage works. The sludge did not contain any microscopically detectable forms of fungoid growth. It was found that the fungi in activated‐sludge medium grow well and both in the forms of single cells, occuring independently and in chains, as well as in the form of long branched filaments. In some instances, the micromycetes formed up to 80 to 100 per cent of the biocenosis of the activated‐sludge flocs, but the dependency of their development on the increasing BOD:N ratios in the waste water has not been ascertained.Fifteen species of micromycetes were isolated and identified, and in addition several representatives of Saccharomycetaceae, which were not identified.

A study of the partition of copper in pig slurry and the effect of substrate copper content on the growth of Leptomitus lacteus

AbstractSamples of pig slurry were fractionated into solid and liquid fractions and analysed for copper using atomic absorption spectrophotometry. The analyses showed that the copper present was associated almost entirely with the solid fractions. The effects of storage temperature on the partition of copper between the groups of slurry fractions were investigated and a study of the effects of different concentrations of copper on the growth of the fungus Leptomitus lacteus was made.

The effects of refuse-tip liquor upon stream biology

An assessment was made of the effects of drainage from five refuse-tips upon the biology of the receiving watercourses. Three refuse-tips were found to be the cause of gross pollution of the stream, resulting in massive growths of sewage fungus Leptomitus lacteus, with the invertebrate community dominated by the oligochaete Nais elinguis over a considerable distance downstream. Chironomidae and the oligochaetes Tubifex ignotus, T. tubifex and Lumbriculus variegata were frequent immediately below discharges. The absence of many invertebrate species appears to be associated with the presence of massive growths of sewage fungus in the stream trapping silt and blocking the interstices between stones, and the increase in pollution.

Respiratory Electron Transport Systems of Aquatic Fungi. I. Leptomitus lacteus and Apodachlya punctata

The electron transport systems of 2 species of aquatic fungi, Leptomitus lacteus and A podachlya punctata, contained cytochrome a-a(3) (605 mmu), 2 b type cytochromes (564 and 557 mmu), c type cytochrome (551 mmu), and flavoprotein, but they appeared to lack cytochrome c(1). Reduced-minus-oxidized difference spectra and difference spectra in the presence of antimycin A or cyanide were used to characterize these systems. Studies with the electron microscope revealed that hyphae of Leptomitus lacteus contained numerous, conspicuous mitochondria with tubular cristae.

Studies in the Leptomitaceae. II. Cytology of Apodachlya Brachynema and Sapromyces Reinschii

(1935). Studies in the Leptomitaceae. II. Cytology of Apodachlya Brachynema and Sapromyces Reinschii. Mycologia: Vol. 27, No. 3, pp. 274-285.

Observations on some British water moulds (Saprolegniales and Blastocladiales)

An examination has been made of the natural waters of the Bristol district, using methods recommended by American workers. Twenty-two species of aquatic fungi have been found, fourteen of which have not before been recorded in this country; these have been fully described. Species found (a) Species already recorded in this country: Saprolegnia ferax Kützing, Achlya colorata Pringsheim, A. polyandra Hildebrand, A. apiculata de Bary, Dictyuchus monosporus Leitgeb, Leptomitus lacteus Agardh, Pythiomorpha gonapodioides Petersen and Blastocladia Pringsheimii Reinsch. (b) Species new to this country: Achlya de Baryana Humphrey, A. Kiebsiana Pieters, A. caroliniana Coker, A. Orion Coker & Couch, A. radiosa Maurizio, A. oblongata de Bary, A. oblongata var. gigantica nov.var., A. megasperma Humphrey, A. recurva Cornu, A. apiculata var. prolifica Coker & Couch, Calyptralegnia achlyoides Coker & Couch, Brevilegnia diclina Coker, Rhipidium europaeum von Minden, R. europaeum var. compactum nov.var., R. americanum Thaxter.