Zoosporangia survival, dehiscence and zoospore formation, and motility in the green algaRhizoclonium hieroglyphicum as affected by different factors

2004 ◽  
Vol 49 (5) ◽  
pp. 549-556 ◽  
Author(s):  
S. Gupta ◽  
S. C. Agrawai
Keyword(s):  
Zoospore Formation

CHEMICAL AND BIOLOGICAL PROPERTIES OF CULTURE FILTRATES OF WESTIELLOPSIS PROLIFICA AND CHAETOPHORA ATTENUATA

1996 ◽  
Vol 44 (1) ◽  
pp. 43-48 ◽  
Author(s):  
S.C. Agrawal ◽  
U.K. Sharma
Keyword(s):  
Amino Acids ◽  
Aspartic Acid ◽  
Free Amino ◽  
Biological Properties ◽  
Total Chlorophyll ◽  
Total Chlorophyll Content ◽  
Westiellopsis Prolifica ◽  
Total Free Amino Acids ◽  
Zoospore Formation ◽  
Growth And Reproduction

Westiellopsis prolifica Janet and Chaetophora attenuata Hazen cultures released sugars (glucose, fructose, and sucrose), organic acids (oxaloacetic acid and oxalic acid), amino acids, and protein. W. prolifica cultures released the amino acids glycine, serine, cystine, glutamic acid, aspartic acid, and α-alanine, while C. attenuata cultures released glycine, serine, aspartic acid, and α-alanine. W. prolifica and C. attenuata cultures of all ages released more extracellular protein than total free amino acids. Cultures of C. attenuata released more protein than cultures of the same age of W. prolifica. The filtrates from old cultures of W. prolifica and C. attenuata decreased the total chlorophyll content of all algae tested, totally suppressed conjugation in Spirogyra decimino and zoospore formation in C. attenuata, and drastically decreased spore germination in W. prolifica, thus producing stressful conditions affecting the growth and reproduction of these and other algae.

Some observations on zoosporogenesis in the female strain of Oedogonium cardiacum

1968 ◽  
Vol 46 (6) ◽  
pp. 767-771 ◽  
Author(s):  
Elizabeth Trerice Retallack ◽  
K. E. Von Maltzahn
Keyword(s):  
Acridine Orange ◽  
Dilute Solutions ◽  
Zoospore Formation ◽  
Intracellular Changes ◽  
Female Strain ◽  
Oedogonium Cardiacum

Developmental cytological events in zoosporogenesis in Oedogonium have been studied in material stained with dilute solutions of acridine orange. Induction leads to isolation of successive protoplasts within the filament. Profound intracellular changes leading to zoospore formation are described and are considered to be the result of cellular isolation. Events during zoosporogenesis are briefly compared to those in oogenesis.

scholarly journals Signatures of Adaptation to Obligate Biotrophy in the Hyaloperonospora arabidopsidis Genome

Science ◽  
2010 ◽  
Vol 330 (6010) ◽  
pp. 1549-1551 ◽  
Author(s):  
Laura Baxter ◽  
Sucheta Tripathy ◽  
Naveed Ishaque ◽  
Nico Boot ◽  
Adriana Cabral ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Inorganic Nitrogen ◽  
Living Plant ◽  
Rxlr Effectors ◽  
Fungal Plant Pathogens ◽  
Genes Encoding ◽  
Zoospore Formation ◽  
Hyaloperonospora Arabidopsidis ◽  
Obligate Biotrophs ◽  
Obligate Biotroph

Many oomycete and fungal plant pathogens are obligate biotrophs, which extract nutrients only from living plant tissue and cannot grow apart from their hosts. Although these pathogens cause substantial crop losses, little is known about the molecular basis or evolution of obligate biotrophy. Here, we report the genome sequence of the oomycete Hyaloperonospora arabidopsidis (Hpa), an obligate biotroph and natural pathogen of Arabidopsis thaliana. In comparison with genomes of related, hemibiotrophic Phytophthora species, the Hpa genome exhibits dramatic reductions in genes encoding (i) RXLR effectors and other secreted pathogenicity proteins, (ii) enzymes for assimilation of inorganic nitrogen and sulfur, and (iii) proteins associated with zoospore formation and motility. These attributes comprise a genomic signature of evolution toward obligate biotrophy.

Zoospore formation in Cylindrocapsa

1975 ◽  
Vol 53 (5) ◽  
pp. 439-451 ◽  
Author(s):  
Larry R. Hoffman ◽  
Cecilia S. Hofmann
Keyword(s):  
Cell Wall ◽  
Vegetative Cell ◽  
Parental Cell ◽  
Wall Material ◽  
Cell Wall Material ◽  
Daughter Cells ◽  
Filamentous Green Algae ◽  
Zoospore Release ◽  
Zoospore Formation ◽  
Altered Cell

Quadriflagellate zoospores and conditions for their induction are described for an algal isolate tentatively identified as Cylindrocapsa geminella Wolle. Previous to this report, only biflagellate zoospores were known for Cylindrocapsa while quadriflagellate zoospores were thought to characterize the closely related Cylindrocapsopsis; this distinction is no longer valid. In our isolate, a vegetative cell may differentiate directly into a single zoospore or, more commonly, zoosporogenesis is preceded by division of a vegetative cell into two, four, or eight daughter cells, each of which becomes a zoospore. Variation in zoospore arrangement depends on the number and nature of the division sequences. Ultimately, zoospores are released from the more-or-less dissociated parental cell wall in one or more vesicles. Each primary vesicle contains one, two, four, or occasionally eight zoospores; zoospore release follows the gradual distention and dissolution of the enclosing vesicle. Light microscopic observations suggest that the zoospore-containing vesicles arise from altered cell wall material. Zoospore germlings and variations in the appearance of vegetative filaments are aiso described and attention is called to the nature of the cell wall, which is quite unlike that of most other filamentous green algae.

ZOOSPORE FORMATION IN A SPECIES OF STIGEOCLONIUM

1940 ◽  
Vol 39 (3) ◽  
pp. 277-282 ◽  
Author(s):  
MARGARET A. P. MADGE
Keyword(s):  
Zoospore Formation

scholarly journals Infective Potential of Sporangia and Zoospores of Phytophthora ramorum

Plant Disease ◽  
2009 ◽  
Vol 93 (1) ◽  
pp. 30-35 ◽  
Author(s):  
T. L. Widmer
Keyword(s):  
Leaf Area ◽  
Phytophthora Species ◽  
Phytophthora Ramorum ◽  
Inoculum Potential ◽  
Phytophthora Spp ◽  
Zoospore Formation ◽  
Inoculum Type ◽  
Infective Potential ◽  
Disk Area ◽  
Leaf Disks

Phytophthora species produce sporangia that either germinate directly or release zoospores, depending upon environmental conditions. Previous Phytophthora spp. inoculation trials have used both sporangia and zoospores as the inoculum type. However, it is unknown what impact propagule type has on disease. Rhododendron leaf disks were inoculated with P. ramorum zoospores (75, 500, or 2,400 per disk), sporangia (75 per disk), or sporangia plus trifluoperazine hydrochloride (TFP) (75 per disk), a chemical that inhibits zoospore formation. Combining results from two different isolates, the highest concentration of zoospores (2,400 per disk) induced a significantly higher percentage of necrotic leaf disk area (96.6%) than sporangia (87.6%) and 500 zoospores per disk (88.7%). The sporangia plus TFP treatment had the lowest necrosis at 47.5%. Rooted rhododendron cuttings had a higher percentage of necrotic leaves per plant when inoculated with zoospores (3,000 or 50,000 per ml) or cysts (50,000 per ml) than with sporangia (3,000 per ml) with or without TFP. The percentage of necrotic leaf area was significantly higher when cysts or zoospores were inoculated at 50,000 per ml than sporangia without TFP and zoospores at 3,000 per ml. All treatments were significantly higher in the percentage of necrotic leaf area than the leaves treated with sporangia plus TFP. This demonstrates that the full inoculum potential may not be achieved when sporangia are used as the inoculum propagule.

Induction of zoospore formation in Thai isolates ofPythium insidiosum

Mycoses ◽  
1990 ◽  
Vol 33 (6) ◽  
pp. 317-323 ◽  
Author(s):  
A. Chaiprasert ◽  
K. Samerpitak ◽  
W. Wanachiwanawin ◽  
P. Thasnakorn
Keyword(s):  
Zoospore Formation
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