Figure 3 - uploaded by Juan M Fregeneda-Grandes
Content may be subject to copyright.
Culture with melon seeds indistilled water at 4° C. A), Saprolegnia australis . 1. Obpyriform oogonium; oospores subcentric; antheridia lacking. 2. Obpyriform oogonium and clasping/wrapping diclinous antheridial branch (Johnson et al., 2002). B), S. australis . Lateral spherical oogonium with more than 6 oospores subcentric, diclinous antheridial branch. Barr= 20 μm . C), S. diclina . Spherical, lateral oogonium; oospores centric (Johnson et al., 2002). D), S. diclina spherical oogonium, wall unpitted, oospores centric. Barr= 25 μm. DA: diclinous antheridium, OC: oospores centric, IO: immature oogonium.
Source publication
Ten species of the family Saprolegniaceae were isolated from the fish farm "El Zarco", State of México, obtained from samples of influent and effluent water of the farm and from infected eggs and individual fish of rainbow trout. Two species belong to the genus Achlya and 8 to Saprolegnia. Saprolegnia ferax is recorded for the first time for the St...
Citations
... oogonia and antheridia) in vitro, which would be necessary for the morphology-based identification [5,10,14]. Some studies have suggested that changing favorable and unfavorable conditions can induce the production of sexual reproductive structures of Saprolegnia strains in vitro, however it could not be applied successfully in every case [11,[15][16][17]. ...
Here, we describe a novel water mold species, Saprolegnia velencensis sp. n. from Lake Velence, in Hungary. Two strains (SAP239 and SAP241) were isolated from lake water, and characterized using morphological and molecular markers. In addition, phylogenetic analyses based on ITS–rDNA regions and on the RNA polymerase II B subunit (RPB2) gene complemented the study. The ITS–rDNA of the two strains was 100% identical, showed the highest similarity to that of S . ferax (with 94.4% identity), and they formed a separate cluster in both the ITS–rDNA and RPB2-based maximum likelihood phylogenetic trees with high bootstrap support. Although mature oogonia and antheridia were not seen under in vitro conditions, the S . velencensis sp. n. could be clearly distinguished from its closest relative, S . ferax , by the length and width of sporangia, as the new species had shorter and narrower sporangia (163.33±70.07 and 36.69±8.27 μm, respectively) than those of S . ferax . The two species also differed in the size of the secondary cysts (11.63±1.77 μm), which were slightly smaller in S . ferax . Our results showed that S . velencensis sp. n. could not be identified with any of the previously described water mold species, justifying its description as a new species.
... S. diclina is a species with low distribution in Lithuania, and its infestation of fish eggs has not been detected. In addition to the widespread Saprolegnia fish pathogens S. parasitica and S. ferax many other members of the genus Saprolegnia: S. delica, S. diclina, S. terrestris, S. aenigmatica, S. anisospora, S. asterophora, S. australis, S. brachydanis, S. glomerata, S. hypogyna, S. furcata, S. uliginosa and S. unispora, S. shikotsuensis have been described as pathogenic or potentially pathogenic to fish(Cao et al., 2012;Dieguez-Uribeondo et al., 2007;Fregeneda-Grandes et al., 2007;Sandoval-Sierra & Diéguez-Uribeondo, 2015;Sandoval- Sierra, Latif-Eugenin, et al., 2014;Thoen et al., 2015;Vega-Ramírez et al., 2013). Previously known as saprotrophs Achlya ambisexualis ...
The present work is the first comprehensive study of fungus‐like stramenopilous organisms (Oomycota) diversity in Lithuanian fish farms aimed at proper identification of saprolegniasis pathogens, which is important for water quality control, monitoring infection levels and choosing more effective treatments for this disease in aquaculture. Pathogenic to fish, Saprolegnia and other potentially pathogenic water moulds were isolated from adult fish, their eggs, fry and from water samples. All detected isolates were examined morphologically and confirmed by sequence‐based molecular methods. A total of eight species belonging to the genera Saprolegnia , Achlya , Newbya and Pythium were identified. Four species ( S. parasitica , S. ferax , S. australis and S. diclina ) were found to be the main causative agents of saprolegniasis in Lithuania. S. parasitica and S. ferax dominated both in hatcheries and open fishponds, accounting for 66.2% of all isolates. S. parasitica was isolated from all farmed salmonid fish species as well as from the skin of Cyprinus carpio , Carassius carassius and Perca fluviatilis . S. australis was isolated from water and once from the skin of Oncorhynchus mykiss , and S. diclina was detected only once on the skin of Salmo salar fish. In addition, Achlya ambisexualis , Saprolegnia anisospora and Newbia oligocantha isolated during this study are noted as a possible source of saprolegniasis. The results of this study are relevant for assessing the risk of potential outbreaks of saprolegniasis or other saprolegnia‐like infection in Lithuanian freshwater aquaculture.
... Thus, it is not surprising that morphology-based identification has taken a back seat to molecular methods. However, notable achievements were reached in this matter when researchers managed to induce the formation of asexual and sexual reproductive structures under different laboratory conditions [7][8][9]. A common view is that the sexual reproductive structures (i.e., oogonia and antheridia) are formed under unfavorable conditions in vitro [10][11][12]. On the other hand, depending on the environmental conditions, oogonia and antheridia may be rare or even absent in in vitro cultures, as others have found [7,8]. ...
... A common view is that the sexual reproductive structures (i.e., oogonia and antheridia) are formed under unfavorable conditions in vitro [10][11][12]. On the other hand, depending on the environmental conditions, oogonia and antheridia may be rare or even absent in in vitro cultures, as others have found [7,8]. Sometimes cultures tend to yield abortive oospores in nutrient-poor environments, whereas normal oogonia and oospores may re-appear in the presence of a host organism when conditions become favorable [13,14]. ...
... Sexual reproductive gans were not observed in any of the isolates or circumstances in our study. Similar resu were reported by Vega-Ramírez et al. [8] when sexual reproduction was not observed any of the 34 S. parasitica isolates examined or by Yuasa and Hatai [7], who found tha of 15 S. parasitica isolates produced oogonia after two weeks of incubation. ...
These authors contributed equally to this work. Abstract: Saprolegnia parasitica Coker, 1923 is a primary fish pathogen and one of the most common water molds in freshwater ecosystems. In our study, nineteen strains of S. parasitica were isolated, identified, and characterized using morphological and genetic markers. On the basis of the abundance of zoosporangia, gemmae, the formation of gemma chains, and the induction of zoospore release, three morphotypes were differentiated. A species-level molecular identification of isolates was performed using the ITS 1 and 2 regions. A total of six genotypes were distinguished based on partial DNA sequences of the genes RNA polymerase II subunit B (RPB2) and serine hydroxymethyl-transferase (SHMT). In five settings of in vitro culture conditions differing in the mineral content and the temperature of water and in the presence of a host or bait, we found that the addition of fish skin extract boosted the formation of asexual reproductive and persistent vegetative structures in cultures, whereas an unfavorable environment did not support the formation of these structures in vitro.
... S. australis has been isolated from infected eggs of salmonids, crucian carp in Southern China and Nile tilapia in Egypt (Liu et al. 2015;Zahran et al. 2017), and the species is reported to be pathogenic in opportunistic condition . Vega-Ramírez et al. (2013) opined that long-stalked pitted obpyriform, elongated or spherical oogonia with partially or nearly filling sub-centric oospores and predominantly diclinous antheridial branches are the distinguished features of S. australis and S. diclina. Similar results were reported in sequence analysis of Saprolegnia from crucian carp eggs in Southern China and Nile tilapia (El-Ashram et al. 2007;Zahran et al. 2017). ...
... Morphological characters of S. australis described briefly by Vega-Ramírez et al. (2013) include dense to diffuse mycelium; slender hyphae and cylindrical sporangia dimorphic spores; abundant gemmae; and clavate, single terminal or intercalary, pitted and smooth wall with terminal oogonia. Oogonial stalks in length: straight, curved, twisted or irregular and unbranched. ...
Global harvest of aquatic biota which includes flora and fauna both, through capture fisheries has already reached its maximum potential, or has shown offshoot in some cases. Capture fisheries is now stagnant, and therefore, in order to fulfil the need for growing worldwide population, culture fisheries have come up with a promising way. To further increase the production and sustainability of culture fisheries, various tools and techniques of biotechnology can be used. Aquatic biotechnology, which has both basic and spin-off applications, can help aquaculture producers increase output, efficiency, profitability, and sustainability. Genomic and proteomic research such as whole genome sequence (WGS) and marker-assisted selection (MAS) of economically important cultured fish could have an impact on fish genetic resource development and management as well. In genetically modified (GM) and gene knockout (GKO) fishes, economically important features such as improved growth, enhanced muscle mass, cold tolerance and disease resistance can be further improved. Cryopreservation of gametes (sperms and eggs) and embryos could open up new commercial possibilities for endless seed and fry production, as well as healthier and better-conditioned fish and brood stock management. It could also help with ex situ genome conservation in threatened and endangered species. Biotechnological interventions in intensive aquaculture have shown a considerable potential in using bioremediation and probiotics to regulate effluents, toxicants, and pathogens in the environment. Therefore, molecular tools can be used to minimize the impact of intensive aquaculture in environmental pollution.KeywordsAquatic biotechnologyBiotechnological interventionsGene knockoutBrood stock genetic managementProteomeMarker-assisted selection
... In this study, the isolates KMG 1-3 from infected eggs of rainbow trout showed no sexual reproduction, and the asexual characters were featured with an abundance of gemmae in chains or catenulate shapes. Sterility is a common feature of many isolates obtained from fish lesions and infected eggs (Ke et al. 2009;Vega-Ramírez et al. 2013;Shaheen et al. 2015;Tandel et al. 2021). How- ever, based on sequence analysis of the ITS region of the rDNA, the isolates KMG1 and 2 were identified as S. salmonis and the isolate KMG3 was detected as S. parasitica. ...
In the present study, we aimed to identify Saprolegnia spp. from infected rainbow trout eggs in a hatchery in the north (Mazandaran province) of Iran. Morphological identification was conducted by light microscopic observation of various life stages of Saprolegnia. For the molecular characterization, the internal transcribed spacer (ITS) region was amplified by using universal primers ITS 1 and ITS 4. Based on morphological and molecular findings, two Saprolegnia spp. have been identified. i.e., Saprolegnia parasitica (Isolate KMG3, MW819780) and S. salmonis (Isolates KMG1, MW819740 and KMG2, MW819707). It is worth mentioning that the latterS. salmonis-is the first report in Iran. The phylogenetic tree inferred by a Neighbor-Joining model revealed that three representative isolates with a well-supported value together with the known isolates of S. parasitica and S. salmonis formed a well-defined clade. An in vitro experiment was conducted to study the growth of S. salmonis (KMG2) and S. parasitica (KMG3) at various incubation temperatures. Both species showed similar hyphal growth rates at 10 and 18°C after 3 days of incubation (P > 0.05).
... Ecology and distribution: Species isolated from water, soil, surface sediments samples, organic matter, as well as from fishes and their eggs in many countries in Africa, Asia, Europe, and North and South America (Johnson et al. 2002;Czeczuga et al. 2005;Steciow et al. 2012;Vega-Ramirez et al. 2013;N'Guessan et al. 2019). ...
In this study, we isolated and identified oomycete species of the genus Saprolegnia. Saprolegnia atlantica, a new species isolated from soil and freshwater bodies in areas of the Atlantic Rainforest (São Paulo state, Brazil), is described herein based on morphology and phylogenetic analyses of combined ITS and LSU regions of the nuclear ribosomal DNA (nc rDNA). Taking into account the oospore type and/or the presence of terminal oogonia with androgynous antheridia, this new species appears to be related to S. litoralis and S. terrestris, but the phylogenetic placement of the isolates did not corroborate this relationship. Saprolegnia aenigmatica, S. blelhamensis, S. glomerata, and S. milanezii were also identified in the soil and submerged leaves, surface sediment, and/or water samples from freshwater bodies collected for the study. These specimens were sequenced, included in phylogenetic analyses, and described, commented and/or illustrated. Saprolegnia glomerata is a first report for Brazil, first sequences of S. blelhamensis and S. glomerata were deposited in GenBank, and Brazilian isolates of S. blelhamensis and S. glomerata are designated as epitypes. Our phylogenetic analyses of the Saprolegnia clade and previously published studies suggest that S. bulbosa, S. longicaulis, S. oliviae, and S. maragheica are new synonyms of S. ferax, and S. semihypogyna is a new synonym of S. eccentrica.
... One study also compared the effects of H 2 O 2 on eight species of warm-and cool-water fish eggs which identified the concentration of 1,000 mg/L to be most effective in improving hatching rate (Rach et al., 1998). The unfertilized fish eggs are especially vulnerable to fungal infection from the family Saprolegniaceae (Post, 1987), which produces mycelia to facilitate spreading from the nonviable to the healthy eggs and cause egg mortality (Teresa Vega-Ramírez et al., 2013). In the present study, H 2 O 2 treatment at 400 mg/L significantly improved the hatchability and also decreased the egg mortality. ...
Non-nutritional stress during early life period has been reported to promote the metabolic programming in fish induced by nutritional stimulus. Sodium chloride (NaCl) and hydrogen peroxide (H2O2) have been widely applied during fish egg hatching, but the influences on health and metabolism of fish in their later life remain unknown. In the present study, H2O2 treatment at 400mg/L but not 200mg/L significantly increased the loach hatchability and decreased the egg mortality, while NaCl treatment at 1,000 and 3,000mg/L showed no significant influences on the loach hatchability nor egg mortality. Further studies indicated that 400mg/L H2O2 pre-treatment significantly enhanced the antioxidant capacity and the mRNA expression of genes involved in immune response of loach larvae, accompanied by the increased expression of genes involved in fish early development. However, the expression of most genes involved in lipid metabolism, including catabolism and anabolism of loach larvae, was significantly upregulated after 200mg/L H2O2 pre-treatment. NaCl pre-treatment also increased the expression of antioxidant enzymes; however, only the expression of C1q within the detected immune-related genes was upregulated in loach larvae. One thousand milligram per liter NaCl pre-treatment significantly increased the expression of LPL and genes involved in fish early development. Thus, our results suggested the programming roles of 400mg/L H2O2 pre-treatment during egg hatching in enhancing antioxidant capacity and immune response of fish larvae via promoting fish early development.
... And the in vivo characterization methods revealed diverse pathogenicity potential of the pathogen. A similar study on fish farms of State of Mexico showed a diversity of 10 species of Saprolegniaceae family, these isolates were found previously infecting eggs, rainbow trout and were also obtained from runoff water of farms (Vega-RamÃrez et al., 2013). Also pathogenicity potential varies among the Saprolegnia strains, as reported to cause 0 to 100% fish mortalities (Fregeneda-Grandes et al., 2001), and 89 to 31% cumulative mortality in challenged Atlantic Salmon, Salmo salar by seven pathogenic Saprolegnia strains (Stueland et al., 2005). ...
... The fungal infection in visceral organs as observed in present study is comparable to the Saprolegnia species artificial infection study carried out on Brown trout, Common carp, European eel, Rainbow trout; Zebra fish and other aquatic organisms (Copland and Willoughby, 1982;Alvarez et al., 1995;Pottinger and Day, 1999;Sarowar et al., 2014;Shin et al., 2017;Ashour et al., 2017;Wuensch et al., 2018).The pathogenicity and establishment of hyphae growth on rainbow trout fish eggs in our study is in similarity with the previous studies wherein, Saprolegnia infections were observed on eggs on Brown trout, Carp, Rainbow trout, Atlantic salmon and Zebra fish embryos (Kitancharoen and Hatai, 1996;Hussein et al., 2001;Fregeneda-Grandes et al., 2007;Habib et al., 2010;Vega-RamÃrez et al., 2013;Yahya et al., 2013;Songe et al., 2016;Shin et al., 2017). ...
Saprolegniosis caused by ubiquitous oomycetes pathogen Saprolegnia spp. poses a serious threat to the welfare and fortitude of the fish industry, therefore having potential to inflict severe socioeconomic losses to the stakeholders involved in aquaculture trade. In this study, Saprolegnia delica was isolated for the first time from naturally infected farmed fish in Kashmir Himalayas, India. The isolate was identified by a combination of (macro and micro morphological) and molecular approaches, the latter involving sequencing of the entire internal transcribed spacer region. The identified S. delica was further evaluated for its pathogenic potential in an artificial setting by using in vivo models, Scale Carp (Cyprinis carpio communis) fingerlings and Rainbow Trout (Oncorhynchus mykiss) eggs. We used intraperitoneal injection and bath immersion means for challenging the host, our results indicated that S. delica is highly pathogenic to both, the fish fingerlings of scale carp and the eggs of rainbow trout. Also, intraperitoneal inoculation was observed to cause higher mortality (55%) in scale carp fingerlings compared to the bath immersion method. The postmortem and histopathology analyses revealed that S. delica is severely infecting skin, gills, eyes and other visceral organs, which led to the infection of multiple organs causing high mortality. However, severity of the disease depends on the route of infection in fingerlings, the time of exposure and the concentration of spores inoculated to eggs. The study presents the first isolation and detection of S. delica infecting rainbow trout in fish farm of Kashmir valley, hence, provides a way forward for the establishment of management strategies aimed at controlling saprolegniosis.
... Oomycetes also referred as fungal like pathogens are sometimes reported as saprophytes on plants and animal debris, but are exclusive parasites of aquatic organisms. Species of Saprolegnia, Aphanomyces, and Achylia among oomycetes and Mucor among zygomycetes have significantly influenced the health of wild and cultured fish, their eggs, embryos and fingerlings [15,[39][40][41][44][45][46][47][48][49]. Saprolegnia pathogens reported from teleost fish include Saprolegnia australis, S. delica, S. declina, S. ferax, S. glomerata, S. parasitica, S. terrestris, and S. uliginosa [18,46,[50][51][52][53][54]. ...
... Species of Saprolegnia, Aphanomyces, and Achylia among oomycetes and Mucor among zygomycetes have significantly influenced the health of wild and cultured fish, their eggs, embryos and fingerlings [15,[39][40][41][44][45][46][47][48][49]. Saprolegnia pathogens reported from teleost fish include Saprolegnia australis, S. delica, S. declina, S. ferax, S. glomerata, S. parasitica, S. terrestris, and S. uliginosa [18,46,[50][51][52][53][54]. As far as the isolation, culturing and identification of FFPs from diseased fish is concerned, classical microbiological and molecular approaches have proven to be integral part in understanding, taxonomy, etiology and early diagnosis of the disease [26,55,56]. ...
Cultured fisheries of developing countries are continously challenged by a number of pathogenic microbes. Among microbial diseases, fungal and fungal like pathogen outbreaks lead to negative social and economic impacts on stakeholders. The cultured fisheries of Kashmir valley are also facing challenge from fungal pathogens , leading to tremendous socioeconomic lossess to the fish farmer community hence, yearns to boost the sector with efficient management strategy. Our study was aimed at investigating the diversity of fungal communities infecting cultured rainbow trout and carp fish species. We employed classical microbiology, macro and micro morphological characteristics, and molecular analysis (multilocus typing) for fungal identification. Also histopathological approach was used to examine the pathogenicity patterns of diverse fungal groups. The study revealed that the infection in fish was predisposed to both superficial as well as visceral organs. However, skin, gills and head were predominantly infected compared to internal organs. The microbiological investigation of infected fish by culture dependent approach helped us to obtain the total of 250 fungal isolates. Out of these isolates, 21 different species were identified belonging to three diverse fungal groups which mostly included 14 species among Ascomycetes, 03 species of Oomycetes and 04 species of Zygomycetes. The majority of fungi which were infectious to cultured fish of valley are biotrophic or opportunistic soil fungi, and some of them being exclusive pathogens of fish.
... In the present study, several isolates from infected skin lesions of Schizothorax richardsonii showed no sexual reproduction, and the asexual characters were featured with an abundance of gemmae in chains or catenulate shape. The unattainable sexual reproduction is a common feature of Saprolegnia parasitica, which is very rarely observed, and the species is distinguished by the presence of gemmae in chains (Vega-Ramírez et al., 2013). Accordingly, based on the morphological features UKC.2, UKC.3, UKC.4, ...
... The isolates were identified by observing the difference in shapes and structures of oogonia, position of lipid droplets and antheridia, which are the major distinguished sexual reproductive characters for species-level identification (Stueland et al., 2005;Ke et al., 2009b). Morphologically, the sexual reproductive characters developed in UKB.1 and STFB.2 isolates were closely related to S. australis, and S. diclina in that they had long-stalked pitted obpyriform, elongated or spherical oogonia with partially or nearly filling subcentric oospores, and predominantly diclinous antheridial branches (Willoughby, 1985;Vega-Ramírez et al., 2013;Cao et al., 2014). Nevertheless, these two species could not be differentiated in the present study based upon the characters of predominantly lateral or terminal oogonia, as described by Vega-Ramírez et al., 2013. ...
... Morphologically, the sexual reproductive characters developed in UKB.1 and STFB.2 isolates were closely related to S. australis, and S. diclina in that they had long-stalked pitted obpyriform, elongated or spherical oogonia with partially or nearly filling subcentric oospores, and predominantly diclinous antheridial branches (Willoughby, 1985;Vega-Ramírez et al., 2013;Cao et al., 2014). Nevertheless, these two species could not be differentiated in the present study based upon the characters of predominantly lateral or terminal oogonia, as described by Vega-Ramírez et al., 2013. The overlap in morphological characteristics thus led to further identification based on molecular techniques. ...
Snow trout, Schizothorax richardsonii, in early as well as in advance life stages are highly susceptible to Saprolegnia spp. infections. In the present study, we aimed to identify the Saprolegnia spp. from different life stages of infected snow trout eggs, juveniles, and adults from two geographic regions, Bhimtal and Champawat of Central Himalaya, India. Morphological identification was carried out by microscopic observation of life stages of Saprolegnia. For the molecular characterization, the internal transcribed spacer region (ITS) was amplified using universal primers ITS 1 and ITS 4. On the basis of the morphological and molecular findings, we have identified two Saprolegnia species from snow trout, i.e., Saprolegnia parasitica from eggs and adults; and S. australis from eggs and juveniles. In particular, S. parasitica was isolated from both geographical regions and S. australis only from Bhimtal, where a comparatively higher temperature regime prevails. An in-vitro experiment was conducted to study the growth of Saprolegnia spp. in varying incubation temperatures. The results confirmed that S. australis could not thrive at or below 7 °C, whereas S. parasitica could grow within the temperature range of 4–20 °C.
