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Inhibition of attachment of some fouling diatoms and settlement of Ulva lactuca zoospores by film-forming bacterium and their extracellular products isolated from biofouled substrata in Northern Chile
Silva-Aciares,Fernando; Riquelme,Carlos;
Electronic Journal of Biotechnology , 2008,
Abstract: the biofouling of surfaces submerged in the marine environment includes primary colonization of the substrate by microorganisms including bacteria, microalgae, and microscopic reproductive propagules of macroorganisms such as algal zoospores. the present study reports the evaluation of the inhibitory potential of biofilms and extracellular products (ep) of the indigenous bacterium alteromonas sp strain ni1-lem on the settlement of marine biofouling such as: (i) eight marine benthic diatoms and (ii) zoospores of the alga ulva lactuca, as well as the germination of these zoospores and was compared with reference strains with proven antifouling properties, halomonas marina (atcc 25374) and pseudoalteromonas tunicata. highest antifouling activity was found for the indigenous strain. in attempts to better define the chemical nature of the antifouling substance in the ep of the alteromonas sp strain ni1-lem, the culture filtrates were tested for activity after heat treatment, enzymatic treatments, dialysis through semipermeable membranes, and separation into polar (aqueous) and non-polar (organic) fractions. the results suggested that the antifouling substance in the culture filtrates to be protein or peptide in nature, thermostable, hydrophilic, and equal to or greater than 3500 daltons in molecular size. antifouling substances from bacteria may lead to the development of novel antifouling agents in the future.
Autonomous movement, root location and infection by sporangial and cyst derived zoospores of Phytophthora cryptogea isolates in water  [cached]
Indian Phytopathology , 2011,
Abstract: The ability of cyst derived zoospores (CDZs) and sporangial derived zoospores (SDZs) to move autonomously in water in model mazes and linear troughs and to infect roots of vinca ( Catharanthus roseus) seedlings at fixed distances from a point of introduction were assessed at 4 h for two isolates of Phytophthora cryptogea (FWDM4 and FDM51). The study showed that both CDZs and SDZs infected roots at distances up to 215 mm (in model mazes) and 320 mm (in linear troughs), and were also able to move the same distances in controls without seedlings. A concentration of 104 zoospores/ml when used at the point of introduction in linear troughs, SDZs and CDZs of the isolate, FDM51 moved actively and infected roots to a distance of 320 mm. SDZs and CDZs of FWDM4 infected seedlings at distances of 240 mm and 320 mm respectively and both the isolates were recovered at 320 mm without seedlings. The results indicate that the CDZs of Phytophthora cryptogea can serve as effective dispersal and infection units in water and suggests that zoospores may be able to move autonomously to greater distances in a non-restraining medium than previously thought.
A novel method for efficient and abundant production of Phytophthora brassicae zoospores on Brussels sprout leaf discs
Klaas Bouwmeester, Francine Govers
BMC Plant Biology , 2009, DOI: 10.1186/1471-2229-9-111
Abstract: P. brassicae isolates were tested for pathogenicity on Brussels sprout plants (Brassica oleracea var. gemmifera). Microscopic examination of leaves, stems and roots infected with a GFP-tagged transformant of P. brassicae clearly demonstrated the susceptibility of the various tissues. Leaf discs were cut from infected Brussels sprout leaves, transferred to microwell plates and submerged in small amounts of water. In the leaf discs the hyphae proliferated and abundant formation of zoosporangia was observed. Upon maturation the zoosporangia released zoospores in high amounts and zoospore production continued during a period of at least four weeks. The zoospores were shown to be infectious on Brussels sprouts and Arabidopsis.The in vitro leaf disc method established from P. brassicae infected Brussels sprout leaves facilitates convenient and high-throughput production of infectious zoospores and is thus suitable to drive small and large scale inoculation experiments. The system has the advantage that zoospores are produced continuously over a period of at least one month.Plants can be affected by a broad range of plant-pathogenic oomycetes, such as downy mildews and Phytophthora species. Comprehensive knowledge of host-pathogen interactions is a prerequisite for designing novel control strategies. Elucidation of these complex interactions will especially benefit from easy and user-friendly model pathosystems. One of the potential model systems is the interaction between Phytophthora brassicae and Arabidopsis [1].P. brassicae was initially classified as P. porri, a major pathogen causing white tip disease on Allium species [2,3], but based on detailed characterization, including isozyme pattern, ITS sequence, morphology and host-pathogenicity, it is now categorized as a new and distinct species [4,5]. P. brassicae has a narrow host range restricted to brassicaceous plants and was shown to be pathogenic on different Brassica species, e.g. Chinese cabbage (Brassica rapa su
The use of hematology method and blood endoparasite observation for determining catfish (Clarias gariepinus) health in fishery Mangkubumen, Boyolali
Biodiversitas , 2007,
Abstract: This research aims to find out the health condition of catfish (Clarias gariepinus) based on hematology and to find out the blood endoparasite type of catfish (Clarias gariepinus) bred in Mangkubumen Boyolali. The sample collection of catfish in this research was conducted in Mangkubumen, Boyolali. The catfish becoming the sample had following criteria: 3 month old, 100-150 gr weight, and 20-25 cm long. The sample of catfish was taked from 5 pools, it was taken 10 fishes from each pool. The hematological parameter measurement including erythrocyte number , leukocyte number, hemoglobin content, hematocrit value, and the preparation of blood smear preparation was conducted in UNS central laboratory. The hematological parameter data of catfish sample obtained was compared with the hematological parameter of the healthy catfish. The smear preparation was used for observing the endoparasite existence on sample blood of catfish. The result of research shows the hematocrit value of 19.3 – 23.3 %, the erythrocyte number of 1.4 – 2.5 x 106 cells/mm3, the hemoglobin content of 6.46 – 7.93 Hb/100ml below that of the healthy catfish. The leukocyte number 650 – 750 x 103cells/mm3 above that of the healthy catfish. Entire catfish indicate the sickness due to the parasite infection. Endoparasit found in the blood of catfish are: Trypanosoma sp, Sanguinicola sp, Haemogregarina sp.
Pathogenic infection of the secondary zoospores of Plasmodiophora brassicae Woron

杨晓琴,马冠华,周丹妮,陈国康,肖崇刚,Yang Xiaoqin,Ma Guanhua,Zhou Danni,Chen Guokang,Xiao Chonggang
- , 2015, DOI: 10.13802/j.cnki.zwbhxb.2015.02.007
Abstract: 为明确芸薹根肿菌Plasmodiophora brassicae Woron.在其它寄主中是否广泛存在性短循环及次生游动孢子的侵染致病性, 以不结球白菜为寄主培养3批幼苗(G1、G2和G3), 用休眠孢子悬浮液接种G1, 被侵染的G1接种G2, 被侵染的G2接种G3, 采用离心管水培法研究其侵染致病性。结果显示, 性短循环研究中, G1、G2和G3根毛均被侵染, 除G3并株接种侵染率为33.33%外, 其它处理侵染率均在50.00%以上, 根毛里有明显的游动孢子囊;次生游动孢子能侵染不结球白菜的皮层组织, 致使不结球白菜发病形成明显的肿根;G1、G2和G3水培发病率为20.00%、15.00%和6.00%, 砂培发病率为22.50%、18.75%和7.50%;G3肿根病理切片中可观察到休眠孢子。表明芸薹根肿菌侵染不结球白菜时, 其生活史中存在性短循环, 次生游动孢子具有侵染致病作用。
In this study, the asexual life cycle of Plasmodiophora brassicae Woron. in other hosts and the pathogenicity of secondary zoospore were investigated. Three groups of seedlings (G1, G2 and G3) were cultivated by using non-heading Chinese cabbage Siyueman as the host. With solution culture method, G1 was inoculated with resting spore suspension, and then the infected G1 was used to inoculate G2 and the infected G2 was used to inoculate G3. The results showed that the root hairs of G1, G2 and G3 were successfully infected, in which zoosporangia were obviously observed. The infection rates were all above 50.00%, except G3 (33.33%), which was planted together with G2. The cortical tissue of non-heading Chinese cabbage in G2 and G3 were infected with the secondary zoospores, which could cause clubroot. With water culture method, the incidence of G1, G2 and G3 was 20.00%, 15.00% and 6.00%, respectively. While with sand culture method, the incidence of G1, G2 and G3 was 22.50%, 18.75% and 7.50%, respectively. The resting spores were observed in the swollen roots of G3 based on pathological section. The results indicated that the asexual life cycle exactly existed in P. brassicae-infected non-heading Chinese cabbage, and the secondary zoospores played an important role in the pathogenicity.
Characterization of Amoeboaphelidium protococcarum, an Algal Parasite New to the Cryptomycota Isolated from an Outdoor Algal Pond Used for the Production of Biofuel  [PDF]
Peter M. Letcher, Salvador Lopez, Robert Schmieder, Philip A. Lee, Craig Behnke, Martha J. Powell, Robert C. McBride
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0056232
Abstract: Mass culture of algae for the production of biofuels is a developing technology designed to offset the depletion of fossil fuel reserves. However, large scale culture of algae in open ponds can be challenging because of incidences of infestation with algal parasites. Without knowledge of the identity of the specific parasite and how to control these pests, algal-based biofuel production will be limited. We have characterized a eukaryotic parasite of Scenedesmus dimorphus growing in outdoor ponds used for biofuel production. We demonstrated that as the genomic DNA of parasite FD01 increases, the concentration of S. dimorphus cells decreases; consequently, this is a highly destructive pathogen. Techniques for culture of the parasite and host were developed, and the endoparasite was identified as the Aphelidea, Amoeboaphelidium protococcarum. Phylogenetic analysis of ribosomal sequences revealed that parasite FD01 placed within the recently described Cryptomycota, a poorly known phylum based on two species of Rozella and environmental samples. Transmission electron microscopy demonstrated that aplanospores of the parasite produced filose pseudopodia, which contained fine fibers the diameter of actin microfilaments. Multiple lipid globules clustered and were associated with microbodies, mitochondria and a membrane cisternae, an arrangement characteristic of the microbody-lipid globule complex of chytrid zoospores. After encystment and attachment to the host cells, the parasite injected its protoplast into the host between the host cell wall and plasma membrane. At maturity the unwalled parasite occupied the entire host cell. After cleavage of the protoplast into aplanospores, a vacuole and lipids remained in the host cell. Amoeboaphelidium protococcarum isolate FD01 is characteristic of the original description of this species and is different from strain X-5 recently characterized. Our results help put a face on the Cryptomycota, revealing that the phylum is more diverse than previously understood and include some of the Aphelidea as well as Rozella species and potentially Microsporidia.
Edgar Beltrán Sánchez,Elizabeth Gilchrist Ramelli,Sonia del Carmen Jaramillo Villegas,Sebastián Reynaldi
Revista Facultad Nacional de Agronomía, Medellín , 2009,
Abstract: La sarna polvosa es una enfermedad que decrece la producción de papa. Es causada por el parásito obligado Spongospora subterranea f. sp. subterranea, el cual produce grupos de zoosporas enquistadas llamados quistosoros. Cuando las zoosporas están activas pueden infectar raíces y tubérculos iniciando un nuevo ciclo reproductivo. Para estudiar la influencia de las condiciones de incubación sobre la activación de las zoosporas, suspensiones acuosas de quistosoros fueron incubadas bajo diferentes condiciones. Los quistosoros y las zoosporas activas fueron diariamente contados utilizando microscopio óptico. El mayor número de zoosporas activas se encontró al cuarto día de incubación, mientras que el menor número de quistosoros se registró al quinto día de incubación. Esto sugiere que las zoosporas permanecen activas por un corto periodo. El número de zoosporas activas por quistosoro fue significativamente (P<0,05) más alto en agua de red que en agua destilada, y en presencia de luz que en oscuridad. Un mayor número de zoosporas por quistosoro se activó a 19 °C que a 5 °C, pero la presencia de raíz de papa no tubo efecto significativo (P<0,05) en la activación. Estos resultados muestran que las condiciones de incubación pueden aumentar las zoosporas liberadas; sin embargo, el número de zoosporas activas por quistosoro observado no fue mayor de cinco. Más zoosporas por quistosoro eran esperadas, porque un quistosoro es entre 10 y 40 veces mayor que una zoospora. En consecuencia, se necesita un gran número de quistosoros para asegurar la presencia de zoosporas activas en un inóculo. The powdery scab is a disease that decreases potato production. It is caused by Spongospora subterranea f. sp. subterranea. This obligate parasite produces cystosori, which are groups of encysted zoospores. When these zoospores are active, they can infect roots and tubers initiating a new replication cycle. To investigate the influence of the incubation conditions on the zoospore activation, suspensions of cystosori in water were incubated under different conditions. The cystosori and the active zoospores were daily counted under microscope. The higher number of active zoospores was found after four days of incubation, meanwhile the lower number of cystosori was found after five days of incubation. This suggests that zoospores are active for a short period. The number of active zoospores per cystosorus was significantly (P<0.05) higher in tap water than in distillated water, and in presence of light than in dark. More zoospores per cystosorus were activated at 19 °C than at 5 °C, bu
Establecimiento de Ibalia leucospoides (Hymenoptera: Ibaliidae) endoparásito de Sirex noctilio (Hymenoptera: Siricidae) en La Almona (Jujuy, Argentina) Estableshiment of Ibalia leucospoides (Hymenoptera: Ibaliidae) endoparasite of Sirex noctilio (Hymenoptera: Siricidae) in La Almona (Jujuy, Argentina)  [cached]
Susana Muruaga de L'Argentier,Sara Quintana de Quinteros,Claudia Gallardo,Hugo Vilte
Revista de la Sociedad Entomol?3gica Argentina , 2005,
Abstract: El objetivo del presente trabajo fue evaluar el establecimiento y la adaptación de Ibalia leucospoides (Hockenwarth) endoparásito de Sirex noctilio F. en plantaciones de Pinus taeda (L) y Pinus patula (Cham. et Schlecht) en la provincia de Jujuy. Los trabajos se realizaron entre 1997-2002 en un establecimiento forestal de la localidad de La Almona (departamento San Antonio, provincia de Jujuy). Para la ejecución de los mismos, se introdujeron trozas de pinos con larvas del parásito y parejas de adultos de I. leucospoides los que, previa aclimatación en laboratorio, fueron liberados en la zona de estudio. Del análisis de los resultados podemos aseverar que el endoparásito I. leucospoides ha logrado establecerse en forma satisfactoria en la localidad de La Almona, provincia de Jujuy. The objective of the present work was to evaluate the conditions of establishment and the adaptation of Ibalia leucospoides (Hockenwarth) endoparasite of Sirex noctilio F., on Pinus taeda (L.) and Pinus patula (Cham. et Schlecht) plantations in Jujuy province. The research was carried out during the 1997-2002 period, in a forest private estate located in La Almona, San Antonio department, Jujuy, Argentina. Larvae and adult couples of I. leucospoides were introduced after and adaptation period in laboratory conditions, were liberated in plantations. From the analysis of results, we can assert that it was possible to settle down, in satisfactory conditions, populations of endoparasite I. leucospoides.
Transient fusion and selective secretion of vesicle proteins in Phytophthora nicotianae zoospores  [PDF]
Weiwei Zhang,Leila M. Blackman,Adrienne R. Hardham
PeerJ , 2015, DOI: 10.7717/peerj.221
Abstract: Secretion of pathogen proteins is crucial for the establishment of disease in animals and plants. Typically, early interactions between host and pathogen trigger regulated secretion of pathogenicity factors that function in pathogen adhesion and host penetration. During the onset of plant infection by spores of the Oomycete, Phytophthora nicotianae, proteins are secreted from three types of cortical vesicles. Following induction of spore encystment, two vesicle types undergo full fusion, releasing their entire contents onto the cell surface. However, the third vesicle type, so-called large peripheral vesicles, selectively secretes a small Sushi domain-containing protein, PnCcp, while retaining a large glycoprotein, PnLpv, before moving away from the plasma membrane. Selective secretion of PnCcp is associated with its compartmentalization within the vesicle periphery. Pharmacological inhibition of dynamin function, purportedly in vesicle fission, by dynasore treatment provides evidence that selective secretion of PnCcp requires transient fusion of the large peripheral vesicles. This is the first report of selective protein secretion via transient fusion outside mammalian cells. Selective secretion is likely to be an important aspect of plant infection by this destructive pathogen.
First record of the genus Rhabdias (Nematoda: Rhabdiasidae), endoparasite from Scinax staufferi (Anura: Hylidae) in Mexico
Martínez-Salazar, Elizabeth Aurelia;Pérez-Ponce de León, Gerardo;Parra Olea, Gabriela;
Revista mexicana de biodiversidad , 2009,
Abstract: a lungworm of the genus rhabdias (nematoda: rhabdiasidae) was recovered from scinax staufferi (anura: hylidae) collected in guadalupe victoria mapastepec, chiapas, mexico (15°28'28"n, 92°53'26"w, 102 m). morphology of the nematode is briefly described and compared with other species of the genus, and mainly with parasites of hylids in the neotropical realm. this study represents the first record of a species of rhabdias species parasitizing s. staufferi, and also constitutes the first record of a nematode parasite of hylid frogs in chiapas state, mexico.
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