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Digitale Medien

Reproductive success in the Caribbean octocoral Briareum asbestinum (1992)

Brazeau, Daniel A. ; Lasker, Howard R.

Springer

Marine biology 114 (1992), S. 157-163

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ISSN: 1432-1793

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie

Notizen: Abstract For most sessile marine invertebrates the number of offspring produced by an individual is often determined indirectly from counts of eggs present, with the assumption that all or most become viable offspring. Few field data on the actual number of offspring produced per individual (reproductive success) have been reported. We examined reproductive success in the octocoral, Briareum asbestinum (Pallas), by measuring embryo densities on 40 female colonies on two reefs (Pinnacles and House reefs) in the San Blas Islands, Panama from 1986 to 1988. The percentage of female colonies with mature eggs which subsequently released embryos was low, ranging from 46.6% in 1986 to 5.0% in 1988. Reproductive success was significantly different between reefs. Pinnacles reef had significantly more successful colonies (those releasing embryos) than House reef in all three years and significantly higher embryo densities in 1986 and 1987. There was a significant positive correlation between female reproductive success and the density and proximity of nearby males in both 1986 and 1987. In addition, fertile female branches placed 25 cm away from male branches produced significantly more embryos than female branches placed 50 cm away. In 1988 two groups of female branches were placed at distances of 〈50 cm and 5 m from four large male colonies at Pinnacles reef. Of the 20 female branches placed 5 m from the males none released embryos while 35% (7 of 20 branches) of the branches 〈50cm from males released embryos. These data indicate that simple counts of mature eggs present within female colonics prior to the reproductive season provide a poor estimate of reproductive success in B. ashestinum and that female reproductive success is positively influenced by the close proximity of males.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00350865

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2

Digitale Medien

DNA fingerprints of a gorgonian coral: a method for detecting clonal structure in a vegetative species (1992)

Coffroth, Mary Alice ; Lasker, Howard R. ; Diamond, Margaret E. ; [weitere]

Springer

Marine biology 114 (1992), S. 317-325

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ISSN: 1432-1793

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie

Notizen: Abstract Clonal reproduction, a common life history strategy among sessile marine invertebrates, can lead to high local abundances of one to a few genotypes in a population. Analysis of the clonal structure of such populations can provide insight into the ecological and evolutionary history of the population, but requires markers that can identify individual genets. Forensic and demographic studies have demonstrated that DNA fingerprinting can provide markers that are unique for an individual genotype. We have generated DNA fingerprints for over 70 colonies of the clonal gorgonian, Plexaura A (Plexaura sp. A) collected from June 1990 through July 1991 in the San Blas Islands, Panama. DNA fingerprints within a singic individual were identical and fingerprinting resolved multiple genotypes within and among reefs. On one reef in the San Blas Islands, Panama, 59% of the colonies sampled were of one genotype and this genotype was not found on any other sampled reefs. A previous study using tissue grafts identified 13 putative clones on these reefs, while DNA fingerprints of the same colonies differentiated 17 genotypes. The present study demonstrates the utility of DNA fingerprinting for distinguishing clones and for identifying clonal structure of marine invertebrate populations.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00349534

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3

Digitale Medien

Mandibular gland secretions of the male beewolvesPhilanthus crabroniformis, P. barbatus, andP. pulcher (Hymenoptera: Sphecidae) (1992)

McDaniel, C. A. ; Schmidt, J. O. ; Howard, R. W.

Springer

Journal of chemical ecology 18 (1992), S. 27-37

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ISSN: 1573-1561

Schlagwort(e): Philanthus crabroniformis ; Philanthus barbatus ; Philanthus pulcher ; Hymenoptera ; Sphecidae ; beewolf ; mandibular glands ; pheromones ; semiochemicals ; mass spectrometry ; infrared spectroscopy

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie , Chemie und Pharmazie

Notizen: Abstract The composition of the territorial marking pheromones from mandibular glands of males of the beewolvesPhilanthus crabroniformis, P. barbatus, andP. pulcher have been determined. The structures of the components were elucidated by gas chromatography-mass spectrometry and gas chromatography-Fourier transform infrared spectroscopy. The major compound ofP. crabroniformis is isopropyl tetradecanoate, with somewhat lesser amounts of 2-tridecanone, 3-methyl-3-butenyl tetradecanoate, and 92∶8 (Z)∶(E)-11-eicosen-1-ol. The major compounds ofP. barbatus are ethyl tetradecanoate and hexadecanal, which are present in approximately a 60∶40 ratio. These two compounds comprise over 95% of the neutral lipids. Also present in lesser amounts are ethyl dodecanoate, tetradecanal, hexadecan-1-ol, a Δ x -octadecen-1-ol, and octadecan-1-ol. The major compounds ofP. pulcher are ethyl (Z)-7-hexadecenoate and geranylgeraniol acetate, which comprise nearly 90% of the neutral lipid fraction, with smaller amounts of tetradecanal, pentadecanal, and ethyl hexadecanoate; trace amounts of Δ x hexadecenal, hexadecanal, and octadecanal are also present.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00997162

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4

Digitale Medien

Actin in penetration pegs of the fungal rice blast pathogen,Magnaporthe grisea (1992)

Bourett, T. M. ; Howard, R. J.

Springer

Protoplasma 168 (1992), S. 20-26

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ISSN: 1615-6102

Schlagwort(e): Appressoria ; Freeze substitution ; Immunofluorescence ; Plant disease ; Phalloidin ; Pyricularia

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie

Notizen: Summary The penetration peg is the structure used byMagnaporthe grisea to pierce the surface of rice leaves or very hard nonbiodegradable substrates. Penetration pegs produced by appressoria in vitro were examined by electron microscopy and immunofluorescence microscopy using various fluorophore labeled anti-actins. Freeze-substitution preparation of appressoria at early stages of substrate penetration showed that peg cytoplasm consisted primarily of a zone of exclusion, excluding even ribosomes, and was continuous with a similar region in the appressorium. Apical vesicles were, however, observed in short, presumably elongating pegs. Immunofluorescence microscopy was used to demonstrate binding of a monoclonal anti-actin to penetration peg cytoplasm, following “permeabilization” of appressoria by means of a brief sonication. Occasional filaments and ca. 300 nm diameter plaques were labeled in appressorial cytoplasm. Western blot analysis of germ tube extracts showed that the monoclonal probe bound predominantly to a single band with a molecular weight similar to that of rabbit muscle actin. Preincubation of the antibody with actin virtually eliminated peg labeling. We conclude that the penetration peg contains actin which may play a role in the formation of the zone of exclusion.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01332647

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