Oomycete Research Articles

Efficacy of Polymerase Chain Reaction in Diagnosis of Saproleniosis in Oreochromis Niloticus

The present study was carried out on 100 cultured Nile tilapia (O. niloticus) of different ages were collected from farms of Central Laboratory for Aquaculture Research (Abbassa, Abou Hammad, Sharkia, Egypt) during period from late November, 2014 to march, 2015. The collected fish samples were studies for presence of fungal infection. Fish were clinically showed respiratory manifestation, erratic movement, loss of equilibrium, off food and also showed whit to gray patches of filamentous mycelium “cotton like” on fish skin, around head, dorsal and caudal fins, gills, on the muscular layer and eye causing unilateral or bilateral eye opacity. Internally, the diseased fish showed, pale gills, dark and enlarged liver, kidney and intestine free from any food. The collected samples were suspected to mycological and biochemical identification which initially suggestive of Saprolegnia spp . The tradionally identification was supported by using Polymerase Chain Reaction (PCR) which very important rapid and accurate method to identify Saprolegnia from other water mold. Also, in this study, the antifungal effect of ethanolic extract of Ruta graveolens( natural herbal plant) on Saprolegnia was studied in vitro by disk and well diffusion methods. Further by trials, iodine was an effective antifungal disinfectant for infected fish.

Evaluation of four surgical implantation techniques for age‐0 white sturgeon ( Acipenser transmontanus Richardson, 1836) with a new acoustic transmitter

The goal of this study was to evaluate four implantation techniques by assessing transmitter retention, survival, growth, and wound healing responses in white sturgeon (Acipenser transmontanus Richardson, 1836). A new acoustic transmitter (AT; cylindrical, 0.7 g in air, 24.2 × 5.0 mm, up to 365 days battery life) was developed to monitor age-0 sturgeon; however, an implantation technique is critical to provide guidance for its use in field research. Sturgeon (n = 150, 182–289 mm fork length, 35–116 g) were separated into five treatments (n = 30 per treatment): (i) control, (ii) flank incision with one suture, (iii) flank incision without a suture, (iv) offline incision with one suture, and (v) offline incision without a suture. Fish were implanted with a non-functioning AT and observed for 28 days. Transmitter retention was 100% and only fish in the offline incision without a suture treatment had reduced growth (0.15% mm growth per day) compared to controls (0.38%) over the 28 days study. Suturing caused an increase in incision inflammation, ulceration, and water mold infection. Offline incisions were more susceptible to varicosities than flank incisions. Non-sutured incisions showed greater incision openness, but only during the first 14 days post-implantation. A flank incision without a suture is recommended for implanting this new AT in age-0 white sturgeon.

Water absorption and mold susceptibility of wood flour/polypropylene composites modified with silane‐wax emulsions

Wood plastic composites can absorb water in exterior applications due to the hygroscopicity of wood flour (WF). The cycle of adsorption and desorption process causes damage to the interfacial bonding between WF and polymer matrix, which benefits the fungal attack. In this study, WF was, respectively, immersed with silane, wax emulsion, and their compound systems for modification at different concentrations (1, 2, and 4%, respectively). Then, the modified WF was mixed with polypropylene (PP) to produce WF/PP composites at mass ratio of 6:4. The water absorption and mold susceptibility of the composites against Aspergillus niger were investigated. The results showed that silane can improve the interfacial adhesion between WF and PP. The water uptake of WF/PP composites treated with 4% silane decreased by 6% compared with the control, and the average mold growth rating decreased from level 4 (mold covering of 75–100%) to level 1 (mold covering of 0–25%). The strong hydrophobicity of wax had a negative effect on the interfacial adhesion of the composites. Thus, composites modified with wax and silane‐wax compounds showed higher water uptake than the control. However, the mold resistance of composites was improved in these groups. POLYM. COMPOS., 40:141–148, 2019. © 2017 Society of Plastics Engineers

Short communication:In vitro screening of Sonneratia alba extract against the oomycete fish pathogen, Aphanomyces invadans

Short communication:In vitro screening of Sonneratia alba extract against the oomycete fish pathogen, Aphanomyces invadans

Renovation and design of double casement windows with regard to the occurrence of water vapour condensation or mould on the interior surface of the window jamb

The condensation of water vapour on the interior surface is an indicator of construction dysfunction or ignoring of the surroundings temperature and relative humidity. This paper deals with analysis of the occurrence of condensation on the jamb of double casement windows (windows with two window casements). More precisely, this is a surface in the interior where water vapour condensation or mould occur. For the renovation of existing double casement windows, there are different solutions based on window design: application of double insulating glazing on the interior window casement, application of double insulating glazing on the exterior casement, or installation of a simple window. We first describe measurement of an existing double casement window located in a mountain cottage. Second, the results and comparison of 2D thermal model of different types of double casement window construction. Also, the external insulation of the peripheral wall was included in the model.

Housing as a Determinant of Tongan Children's Health: Innovative Methodology Using Wearable Cameras.

Housing is a significant determinant of health, particularly in developing countries such as Tonga. Currently, very little is known about the quality of the housing in Tonga, as is the case with many developing countries, nor about the interaction between children and the home environment. This study aimed to identify the nature and extent of health risk factors and behaviours in Tongan houses from a child’s perspective. An innovative methodology was used, Kids’Cam Tonga. Seventy-two Class 6 children (10 to 13-year-olds) were randomly selected from 12 randomly selected schools in Tongatapu, the main island. Each participating child wore a wearable camera on lanyards around their neck. The device automatically took wide-angled, 136° images of the child’s perspective every seven seconds. The children were instructed to wear the camera all day from Friday morning to Sunday evening, inclusive. The analysis showed that the majority of Tongan children in the study live in houses that have structural deficiencies and hazards, including water damage (42%), mould (36%), and electrical (89%) and burn risk factors (28%). The findings suggest that improvements to the housing stock may reduce the associated health burden and increase buildings’ resilience to natural hazards. A collaborative approach between communities, community leaders, government and non-governmental organisations (NGOs) is urgently needed. This research methodology may be of value to other developing countries.

Observations and first reports of saprolegniosis in Aanaakłiq, broad whitefish (Coregonus nasus), from the Colville River near Nuiqsut, Alaska

We report the first confirmed cases (2013–2016) of saprolegniosis caused by water mold from the genus Saprolegnia in Aanaakłiq, broad whitefish (Coregonus nasus), from the Colville River near Nuiqsut, Alaska. While this mold is known to be worldwide, these instances represent the first cases in Nuiqsut and only the second instance on a single fish on the North Slope, occurring in 1980. We describe the collaborative work on monitoring this emerging disease. Because fish constitute a critical component of the diet in Nuiqsut and fishing is an integral part of Inupiaq nutritional and cultural subsistence activities overall, individual subsistence fishers, local governmental entities, and Alaska Native organizations representing Nuiqsut requested an examination of affected fish and information on possible drivers of this emerging disease. The collaborative work described here ranges from recording fishermen observations, acquiring fish and mold specimens, histopathology, and molecular identification of the mold. This work, not currently grant-funded, begins with Native observation that incorporates western scientific methods and involves local, state, and federal departments as well as for-profit and non-profit organizations. Additionally, we report the more recent (2016) observation of this disease in a second species of whitefish, Pikuktuuq, humpback whitefish (Coregonus pidschain).

Gross and histopathological study on common carp Cyprinus carpio L. diseases in rearing culturing ponds in Kirkuk Province – Iraq

The present study aimed to investigate the infection ratio and pathological lesions in common carp fish in Kirkuk province. To achieve these goals, a survey study was conducted from 01/12/2015 to 01/04/2016. Results of the survey study showed that the infection ratio of acidity and alkalinity of pond’s water 27.88% (46/165), bacterial kidney infection 20% (33/165), water mold (saprolegniasis) 12.12% (20/165), spring viremia of common carp 11.52% (19/165), Coccidiosis 11.52% (19/165), fungal gill rot infection 7.27% (12/165), hemorrhagic septicemia 6.67% (11/165) and enteric parasite infection 3.03% (3/165). Pathological study showed that lesions in acidic and alkaline of pond’s water consisted from necrosis with sloughing of scales and intestinal mucinous degeneration as well as necrosis of intestinal villi. In bacterial kidney infection lesion consist of diphtheric membrane cover abdominal cavity and presence of microorganisms in renal cortex and medulla. In Saprolegnia sp. infection the pathognomic lesions were recorded which consist from fungal hyphae extended from fish body into water. In spring viremia of common carp lesions consist from exophthalmia and pinpoint hemorrhage on fish body with presence of pseudodiphtheric membrane associated with hemorrhagic exudate as well as extensive necrosis of intestinal villi. In Eimeria sp. infection lesions composed from presence of infective stages of coccidian parasites in enterocytes. In fungal gill rot infection the mosaic appearance lesion was observed consisted from necrotic area (white color) and health area (red color). In hemorrhagic septicemia infection lesions consist from ulcers surrounded by areas of hyperemia with extensive necrosis of intestinal lining. In enteric parasites infection we noted presence of large numbers of worms in intestinal lumen, also there is nodule in intestinal mucosa contain nematods of 2 cm in length, in other cases there is presence of worms inserted in intestinal mucosa of 30 cm length covered with fibrous membrane. It concluded from this study that the infection ratio with different diseases in common carp varied in compared with other countries and depends upon changes in climate and breeding habits as well as the gross and microscopic lesions are identical to that recorded worldwide.

Diversity and bioprospecting potential of rhizo and endophytic bacteria from two mangrove plants in Saudi Arabia

Mangrove plants are located on coastal area of sea and harbor diverse communities of microorganisms. The aim of our present study was to isolate bacteria from two different mangroves collected from the coastal area of Thuwal, Saudi Arabia and to further screen them for their antimicrobial activities. We have isolated 317 different rhizo and endophytic bacteria from mangroves using soil, roots and leave tissues. Bacteria were screened for their antifungal activities against oomycetes pathogens, Phytophthora capsici, Pythium ultimum. Only 25 bacterial strains found to be active against oomycetes fungal pathogens. These bacteria were tested further against other fungal pathogens like Magnaporthe grisea, Altenaria malli, and Fusarium oxysporum. Antagonistic bacteria were further screened for antibacterial activities against human pathogenic bacteria. Only few isolates exhibited antagonistic activity against these pathogenic bacteria. Hydrolytic enzymes production (cellulase, protease, lipase, and amylase) was also assessed. Most of the active isolates exhibited amylase and protease activities. Identification based on 16S rRNA gene revealed 92.8 to 99.9% sequence, similar to type strains of related species. Antagonistic bacteria belong to 5 different classes that is Gammaproteobacteria (γ-Proteobacteria), Alphaproteobacteria (α-Proteobacteria), Firmicutes, Bacteroidetes and Actinobacteria. Our results provide evidence that, mangroves plants harbor potentially useful bacteria producing active metabolites and enzymes. Key words: Mangrove plants, antagonistic bacteria, enzymatic activities, 16S rRNA gene sequence, phylogenetic analysis.

Proteomic Analysis of Compatible Interaction between Sorghum Downy MildewPathogen (Peronosclerospora Sorghi) and Maize (Zea MaysL.)

Proteomic Analysis of Compatible Interaction between Sorghum Downy Mildew Pathogen (Peronosclerospora Sorghi) and Maize (Zea Mays L.) Sorghum downy mildew (SDM) caused by the oomycete, Peronosclerospora sorghi, is one of the destructive diseases that afflict maize. P. sorghi infects a susceptible host, hindering its growth and altering its morphology. To understand the molecular basis of the compatibility interaction between P. sorghi and maize, a comparative proteomic approach (2D-PAGE) was employed between the mock-inoculated (control) and SDM-inoculated leaves in the susceptible genotypes of maize (UMI79 and CM500). Seventeen spots showed a significant difference in the abundance of proteins in control and inoculated samples were further analyzed with MALDITOF/MS. The resulting peptide mass fingerprint was subjected to MASCOT analysis and it was found that most were related to stress that includes lipoxygenase and DEAD-box ATP-dependent RNA helicases, microtubule-associated protein and probable protein disulphide isomerase. Additionally, proteins involved in the cell cycle/endoreplication such as DNA topoisomerase 6 subunit A and retinoblastoma-related proteins were differentially expressed during infection. The possible roles of these proteins in response to P. sorghi infection in maize are discussed...

Complex interactive effects of water mold, herbicide, and the fungus Batrachochytrium dendrobatidis on Pacific treefrog Hyliola regilla hosts.

Infectious diseases pose a serious threat to global biodiversity. However, their ecological impacts are not independent of environmental conditions. For example, the pathogenic fungus Batrachochytrium dendrobatidis (Bd), which has contributed to population declines and extinctions in many amphibian species, interacts with several environmental factors to influence its hosts, but potential interactions with other pathogens and environmental contaminants are understudied. We examined the combined effects of Bd, a water mold (Achlya sp.), and the herbicide Roundup® Regular (hereafter, Roundup®) on larval Pacific treefrog Hyliola regilla hosts. We employed a 2 wk, fully factorial laboratory experiment with 3 ecologically realistic levels (0, 1, and 2 mg l-1 of active ingredient) of field-formulated Roundup®, 2 Achlya treatments (present and absent), and 2 Bd treatments (present and absent). Our results were consistent with sublethal interactive effects involving all 3 experimental factors. When Roundup® was absent, the proportion of Bd-exposed larvae infected with Bd was elevated in the presence of Achlya, consistent with Achlya acting as a synergistic cofactor that facilitated the establishment of Bd infection. However, this Achlya effect became nonsignificant at 1 mg l-1 of the active ingredient of Roundup® and disappeared at the highest Roundup® concentration. In addition, Roundup® decreased Bd loads among Bd-exposed larvae. Our study suggests complex interactive effects of a water mold and a contaminant on Bd infection in amphibian hosts. Achlya and Roundup® were both correlated with altered patterns of Bd infection, but in different ways, and Roundup® appeared to remove the influence of Achlya on Bd.

Mycolactone-producing Mycobacterium marinum infection in captive Hong Kong warty newts and pathological evidence of impaired host immune function.

A mass mortality event of captive Hong Kong warty newts Paramesotriton hongkongensis with non-granulomatous necrotic lesions occurred in Taipei Zoo, Taiwan, in 2014. Clinically, the sick newts were lethargic and often covered with water mold Saprolegnia sp. on the skin of the body trunk or extremities. Predominant pathological findings were multifocal non-granulomatous necrotic lesions in the liver, spleen, and kidneys and severe skin infection with Saprolegnia sp., with deep invasion and involvement of underlying muscles. The possibility of ranavirus infection was ruled out by negative PCR results. Unexpectedly, abundant intralesional acid-fast positive bacilli were found in the necrotic lesions of the liver, spleen, and kidney in all 14 sick newts. PCR targeting the hsp65, ITS region, and partial 16S rRNA genes was performed, and the sequence identity from amplified amplicons of hsp65 and partial 16S rRNA genes was 100% identical to that of the corresponding gene fragment of Mycobacterium marinum. Further molecular investigations demonstrated that the current M. marinum was a mycolactone-producing mycobacterium with the presence of esxA/esxB genes. Mycolactone is a plasmid-encoded, immunosuppressive, and cytotoxic toxin. The possible immunosuppression phenomenon characterized by systemic non-granulomatous necrotic lesions caused by M. marinum and the unusual deep invasive infection caused by water mold might be associated with the immunosuppressive effect of mycolactone. Therefore, it should be noted that non-granulomatous necrotic lesions in amphibians can be caused not only by ranavirus infection but also by mycobacteriosis.

Ultrastructural characterization of the host–parasite interface between Allomyces anomalus (Blastocladiomycota) and Rozella allomycis (Cryptomycota)

Rozella allomycis is an obligate endoparasite of the water mold Allomyces and a member of a clade (= Opisthosporidia) sister to the traditional Fungi. Gaining insights into Rozella's development as a phylogenetically pivotal endoparasite can aid our understanding of structural adaptations and evolution of the Opisthosporidia clade, especially within the context of genomic information. The purpose of this study is to characterize the interface between R. allomycis and Allomyces anomalus. Electron microscopy of developing plasmodia of R. allomycis in host hyphae shows that the interface consists of three-membrane layers, interpreted as the parasite's plasma membrane (inner one layer) and a host cisterna (outer two layers). As sporangial and resting spore plasmodia develop, host mitochondria typically cluster at the surface of the parasite and eventually align parallel to the three-membrane layered interface. The parasite's mitochondria have only a few cristae and the mitochondrial matrix is sparse, clearly distinguishing parasite mitochondria from those of the host. Consistent with the expected organellar topology if the parasite plasmodia phagocytize host cytoplasm, phagocytic vacuoles are at first bounded by three-membrane layers with host-type mitochondria lining the inner membrane. Thus, Rozella's nutrition, at least in part, is phagotrophic in contrast to osmotrophic nutrition of traditional fungi.

Building dampness and mold in European homes in relation to climate, building characteristics and socio-economic status: The European Community Respiratory Health Survey ECRHS II.

We studied dampness and mold in homes in relation to climate, building characteristics and socio-economic status (SES) across Europe, for 7127 homes in 22 centers. A subsample of 3118 homes was inspected. Multilevel analysis was applied, including age, gender, center, SES, climate, and building factors. Self-reported water damage (10%), damp spots (21%), and mold (16%) in past year were similar as observed data (19% dampness and 14% mold). Ambient temperature was associated with self-reported water damage (OR=1.63 per 10°C; 95% CI 1.02-2.63), damp spots (OR=2.95; 95% CI 1.98-4.39), and mold (OR=2.28; 95% CI 1.04-4.67). Precipitation was associated with water damage (OR=1.12 per 100mm; 95% CI 1.02-1.23) and damp spots (OR=1.11; 95% CI 1.02-1.20). Ambient relative air humidity was not associated with indoor dampness and mold. Older buildings had more dampness and mold (P<.001). Manual workers reported less water damage (OR=0.69; 95% CI 0.53-0.89) but more mold (OR=1.27; 95% CI 1.03-1.55) as compared to managerial/professional workers. There were correlations between reported and observed data at center level (Spearman rho 0.61 for dampness and 0.73 for mold). In conclusion, high ambient temperature and precipitation and high building age can be risk factors for dampness and mold in homes in Europe.

Emerging oomycete threats to plants and animals.

Oomycetes, or water moulds, are fungal-like organisms phylogenetically related to algae. They cause devastating diseases in both plants and animals. Here, we describe seven oomycete species that are emerging or re-emerging threats to agriculture, horticulture, aquaculture and natural ecosystems. They include the plant pathogens Phytophthora infestans, Phytophthora palmivora, Phytophthora ramorum, Plasmopara obducens, and the animal pathogens Aphanomyces invadans, Saprolegnia parasitica and Halioticida noduliformans For each species, we describe its pathology, importance and impact, discuss why it is an emerging threat and briefly review current research activities.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'.

A study of anti fungal activity of a combination of essential oils from medical herbs against water molds

The aim of this study is to evaluate the anti fungal activity of a combination of essential oils against water molds. HPLC analysis was done to evaluate the quantity and quality of the active compounds in this combination which extracted from three herbs( Peppermint Menthapiperita ,Thyme Thymusvulgaris, Common sage Salvia officinalis L.) and the active compounds are Camphor,Menthol,,Thujone and Thymol with different concentrations. In this study (MIC) , (MFC) were measured and (LD50) determined after 48,96 h from fingerlings treatment of common carp in aquariums .The results of (MIC) were 0.025µl/ml for Aphanomyces sp. and 0.015µl/ml for both Achlya sp. and Fusariumsolani which showed significant differences(p

HRM: A TOOL TO ASSESS GENETIC DIVERSITY OF PHYTOPHTHORA CAMBIVORA ISOLATES

Phytophthora cambivora (Petri) Buisman is a widespread soil born oomycete causing root rot on several woody species. Together with P. cinnamomi, it is considered the most pathogenic species associated with chestnut ink disease all over Europe. Currently, no efficient control strategies are available for ink disease. Information about the population genetic variability of P. cambivora is quite limited, despite that it might be useful for the development of integrated control programmes. To our knowledge no such studies have been conducted in chestnut-growing regions in Europe. Therefore, we set up a reliable and accurate genotyping approach named HRM (High Resolution Melting) analysis in order to assign efficiently and accurately the signatures of genetic variation among P. cambivora isolates collected in a chestnut growing area in Central Italy. Degenerated primers were designed in conserved regions of exons 3 and 4 of the gene locus Ypt1. The resulting melting curves profiles specifically assigned all P. cambivora isolates in eight unique HRM genotypes according to their normalized curve profiles implying high intraspecific genetic variation of these isolates. Data confirmed that the HRM approach might be on a wide scale a rapid and reproducible technique for efficient intraspecific genotyping of P. cambivora populations.

Effect of oil impregnation on water repellency, dimensional stability and mold susceptibility of thermally modified European aspen and downy birch wood

Conventional chemical wood preservatives have been banned or restricted in some applications due to human and animal toxicity and their adverse impact on the surrounding environment. New, low-environmental-impact wood treatments that still provide effective protection systems are needed to protect wood. Thermal modification of wood could reduce hygroscopicity, improve dimensional stability and enhance resistance to mold attack. The aim of this study was to investigate if these properties enhanced in thermally modified (TM) wood through treatments with oils. In this study, TM European aspen (Populus tremula) and downy birch (Betula pubescens) wood were impregnated with three different types of oil: water-miscible commercial Elit Träskydd (Beckers oil with propiconazole and 3-iodo-2-propynyl butylcarbamate, IPBC), a pine tar formulation and 100% tung oil. The properties of oil-impregnated wood investigated were water repellency, dimensional stability and mold susceptibility. The treated wood, especially with pine tar and tung oil, showed an increase in water repellency and dimensional stability. However, Beckers oil which contains biocides like propiconazole and IPBC showed better protection against mold compared with pine tar and tung oil. To enhance the dimensional stability of the wood, pine tar and tung oil can be used, but these oil treatments did not significantly improve mold resistance rather sometimes enhanced the mold growth, whereas a significant anti-mold effect was observed on Beckers oil treated samples.

Water mold infection but not paternity induces selective filial cannibalism in a goby.

Many animals heavily invest in parental care but still reject at least some of their offspring. Although seemingly paradoxical, selection can favor parents to neglect offspring of particularly low reproductive value, for example, because of small survival chances. We here assess whether filial cannibalism (FC), where parents routinely eat some of their own young, is selective in response to individual offspring reproductive value. We performed two independent laboratory experiments in the common goby (Pomatoschistus microps) to test whether caring fathers preferentially cannibalize eggs of a given infection history and paternity. While males did not discriminate kin from nonkin eggs, they consumed significantly more eggs previously exposed to water mold compared to uninfected eggs. Our findings clearly show that parents differentiate between eggs based on differences in egg condition, and thus complement the prevailing view that FC arises for energetic reasons. By preventing the spread of microbial infections, the removal of molded eggs can constitute an important component of parental care and may represent a key driver of selective FC in a wide array of parental fish.

The effect of Ochratoxin A on antimicrobial polypeptide expression and resistance to water mold infection in channel catfish (Ictalurus punctatus)

Mycotoxin contamination of agricultural commodities poses a serious risk to animal health, including aquaculture species. Ochratoxin A (OA) is the most immunotoxic ochratoxin, yet little is known about its effect on immune function in fish. Antimicrobial polypeptides (AMPPs) are one of the most potent, innate, host defense factors, yet very little is known about what types of chronic stressors affect their expression. Among the most prevalent and potent AMPPs in fish are histone-like proteins (HLPs). In this study, fish were fed 2, 4, or 8 mg OA/kg diet. Skin antibacterial activity and HLP-1 levels were measured on Days 0, 28 and 56. Feeding 2, 4 or 8 mg OA/kg diet resulted in significant growth depression, but higher levels (4 or 8 mg OA/kg diet) resulted in lowering feed intake (FI) and impaired feed conversion ratio. In addition, feeding 8 mg OA/kg diet increased susceptibility to experimental water mold (Saprolegnia) challenge, suggesting that OA toxicity might contribute to some saprolegnosis outbreaks. However, there were no changes in AMPP expression in any treatment group. Our data suggests that the increased disease susceptibility of channel catfish due to OA is probably due to mechanisms other than a direct effect on antimicrobial polypeptide expression.