Parechinus Angulosus Research Articles

Growth, respiration and tentative energy budgets for two populations of the sea urchin Parechinus angulosus (Leske)

The common sea urchin Parechinus angulosus is the dominant herbivore in the southern African kelp beds. Being an integral part of the kelp bed ecosystem, its impact on the system was estimated in terms of its energy budget. Two populations existing under differing temperature regimes were studied. Somatic growth rates were shown to take a sigmoid form and appeared to be governed by type of food consumed and gonad development, there being a seasonal inverse relationship between gonad growth and body growth. Respiration rates are governed by temperature in sexually immature individuals and by the state of the gonads in sexually mature animals. There is a diurnal fluctuation in respiration rate. There is a marked difference in the consumption rates of the two populations, which may be related to the temperature differences at the two sites.

The primary structure of histone H1 from sperm of the sea urchin Parechinus angulosus. 1. Chemical and enzymatic fragmentation of the protein and the sequence of amino acids in the four N-terminal cyanogen bromide peptides.

The primary structure of the amino-terminal 84 residues of sperm histone H1Parechinus has been determined. The sequence is: Pro-Gly-Ser-Pro-Gln-Lys-Arg-Ala-Ala-Ser-Pro-Arg-Lys-Ser-Pro-Arg-Lys-Ser-Pro-Lys-Lys-Ser-Pro-Arg-Lys-Ala-Ser-Ala-Ser-Pro-Arg-Arg-Lys-Ala-Lys-Arg-Ala-Arg-Ala-Ser-Thr-His-Pro-Pro-Val-Leu-Glu-Met-Val-Gln-Ala-Ala-Ile-Thr-Ala-Met-Lys-Glu-Arg-Lys-Gly-Ser-Ser-Ala-Ala-Lys-Ile-Lys-Ser-Tyr-Met-Ala-Ala-Asn-Tyr-Arg-Val-Asp-Met-Asn-Val-Leu-Ala-Pro-.

The Primary Structure of Histone H1 from Sperm of the Sea Urchin Parechinus angulosus. 2. Sequence of the C-Terminal CNBr Peptide and the Entire Primary Structure

The primary structure of sperm histone H1Parechinus has been determined. H1Parechinus consists of a polypeptide chain of the following 248 amino acid residues: Pro-Gly-Ser-Pro-Gln-Lys-Arg-Ala-Ala-Ser-Pro-Arg-Lys-Ser-Pro-Arg-Lys-Ser-Pro-Lys-Lys-Ser-Pro-Arg-Lys-Ala-Ser-Ala-Ser-Pro-Arg-Arg-Lys-Ala-Lys-Arg-Ala-Arg-Ala-Ser-Thr-His-Pro-Pro-Val-Leu-Glu-Met-Val-Gln-Ala-Ala-Ile-Thr-Ala-Met-Lys-Glu-Arg-Lys-Gly-Ser-Ser-Ala-Ala-Lys-Ile-Lys-Ser-Tyr-Met-Ala-Ala-Asn-Tyr-Arg-Val-Asp-Met-Asn-Val-Leu-Ala-Pro-His-Val-Arg-Arg-Ala-Leu-Arg-Asn-Gly-Val-Ala-Ser-Gly-Ala-Leu-Lys-Gln-Val-Thr-Gly-Thr-Gly-Ala-Ser-Gly-Arg-Phe-Arg-Val-Gly-Ala-Val-Ala-Lys-Pro-Lys-Lys-Ala-Lys-Lys-Thr-Ser-Ala-Ala-Ala-Lys-Ala-Lys-Lys-Ala-Lys-Ala-Ala-Ala-Ala-Lys-Lys-Ala-Arg-Arg-leads to Lys-Ala-Lys-Ala-Ala-Ala-Lys-Arg-Lys-Ala-Ala-Leu-Ala-Lys-Lys-Lys-Ala-Ala-Ala-Ala-Lys-Arg-Lys-Ala-Ala-Ala-Lys-Ala-Lys-Lys-Ala-Lys-Lys-Pro-Lys-Lys-Lys-Ala-Ala-Ala-Lys-Lys-Ala-Lys-Lys-Pro-Ala-Lys-Lys-Ser-Pro-Lys-Lys-Ala-Lys-Lys-Pro-Ala-Lys-Lys-Ser-Pro-Lys-Lys-Lys-Lys-Ala-Lys-Arg-Ser-Pro-Lys-Lys-Ala-Lys-Lys-Ala-Ala-Gly-Lys-Arg-Lys-Pro-Ala-Ala-Lys-Lys-Ala-Arg-Arg-Ser-Pro-Arg-Lys-Ala-Gly-Lys-Arg-Arg-Ser-Pro-Lys-Lys-Ala-Arg-Lys. The protein consists of three domains. Compared to other H1 and H5 histones, there is a very similar hydrophobic central domain and the carboxyl-terminal domain is very rich in lysine and alanine. H1Parechinus is similar to H5 histones in that the carboxyl-terminal domain also contains many arginine residues close to the carboxyl terminus. The carboxyl-terminal domain of H1Parechinus appears to have been constructed by a series of variable duplications. The amino-terminal domain of H1Parechinus is longer and quire different to that of other H1 and H5 histones and is characterized by a repeating tetrapeptide of the general type Ser-Pro-(basic)2. The known sequence of a histone H1 gene from Psammechinus miliaris [Schaffner, W. et al. (1978) Cell, 14, 655-671] is compared to the sequence of H1Parechinus. Again the central hydrophobic domains are similar whereas the amino terminal domains are very different. The functions of the various domains of sperm histone H1Parechinus are discussed.

Aspects of Population Structure ofParechinus AngulosusLeske, Around the Cape Peninsula

Aspects of the community structure of Parechinus angulosus, a locally dominant echinoid, were studied in two inshore temperature environments on the Cape Peninsula for a year. Stratified, random tr...

A histone programme during the life cycle of the sea urchin.

The histone complement of chromatin from early gastrula, late gastrula and from fully differentiated gut cells of the sea urchin Parechinus angulosus has been fractionated by molecular sieve and ion-exchange chromatography. Several of the subfractions thus isolated have been characterized by amino acid composition and partial amino acid sequences as a series of variants of the histones H1, H2A and H2B. Specific histone variants are present in chromatin at specific stages of differentiation.

Kelp grazing by the common sea urchinParechinus angulosusLeske in False Bay, Cape

The effect of grazing by the common sea urchin on a local kelp bed was studied. The need for this investigation was felt in view of the importance of kelp beds to the near-shore ecosystem and reports describing the extent of damage to some Californian and eastern Canadian kelp beds by the grazing activity of certain urchin species. Experimental sites typical of the area were permanently marked. A study site was protected from urchins, while the control was not. Urchins were regularly removed from the study site. Kelps growing on the experimental plots were harvested seasonally, counted and their biomass calculated. Results over one year suggest that although the grazing potential of sea urchins is considerable, little impact was made on kelp beds in the study area. The grazing potential of Parechinus seems to be directed principally at the early sporophytes of Ecklonia maxima rather than at adult plants.

The partial amino acid sequences of the two H2B histones from sperm of the sea urchin Psammechinus miliaris

Two new histone H2B variants have been isolated from sperm cells of the sea urchin Psammechinus miliaris. They have been designated sperm histone H2B (1) Psammechinus and sperm histone H2B (2) Psammechinus . Both histones are highly homologous to the previously described sperm histones from Parechinus angulosus (Strickland et al. (1977) Eur. J. Biochem. 77, 263–275 and 277–286). The amino acid sequences of the Ps. miliaris sperm histones, though highly homologous, are not identical to the amino acid sequence derived from the codon sequence of a histone H2B gene, characterized from the same organism by Birnstiel et al. ((1977) Nature 266, 603–607).

The mobilization of maternal histone messenger RNA after fertilization of the sea urchin egg

The extent of protein, RNA and DNA synthesis in early cleavage stages of the sea urchin embryo ( Parechinus angulosus) was determined. A histone mRNA specific cDNA was used in hybridization experiments to investigate the cytoplasmic localization of maternal histone mRNA in the unfertilized sea urchin egg and first cleavage stage embryo. In the unfertilized egg histone mRNA was localized exclusively in ribonucleoprotein particles with none in ribosomes or polyribosomes. This distribution changed after fertilization, in particular, coupled with the first cleavage telophase there was a significant transfer of histone mRNA from the ribonucleoprotein fraction to the polyribosomes. The results indicate mRNA specific translational control mechanisms.

A Simple Method For The Preparation Of Sperm Of External Fertilizers For Scanning Electron Microscopy

A simple technique is described for the study of sperm of some external fertilizers (sea urchin, Parechinus angulosus; teleost, Liza dumerili; anurans, Xenopus laevis and Bufo rangeri) by means of scanning electron microscopy. The technique involves: (i) dilution of sperm with water of the natural environment of the animals or artificial media resembling their natural environment; (ii) spreading of sperm suspension on 10-mm square Perspex plates; (iii) fixation of diluted sperm with 2.5 pH 7.4 Millonig phosphate buffered glutaraldehyde (1 hour); (iv) repeated washing in phosphate buffer, air drying and coating with palladium-gold in a vacuum evaporator. Postfixation with 1% osmium tetroxide did not improve the results and dehydration with an alcohol series was not necessary.

The complete amino-acid sequence of histone H2B(1) from sperm of the sea urchin Parechinus angulosus.

Two histones have been isolated and purified from sperm cells of the sea urchin Parechinus angulosus. They have been designated sperm histone H2B(1) Parechinus and sperm histone H2B(2) Parechinus on criteria of solubility and partial sequence homology with H2Bcalf.H2B(1) consists of a polypeptide chain of the following 144 amino acid residues: Pro‐Ser‐Gln‐Lys‐Ser‐Pro‐Thr‐Lys‐Arg‐Ser‐Pro‐Thr‐Lys‐Arg‐Ser‐Pro‐Thr‐Lys‐Arg‐Ser‐Pro‐Gln‐Lys‐Gly‐Gly‐Lys‐Gly‐Gly‐Lys‐Gly‐Ala‐Lys‐Arg‐Gly‐Gly‐Lys‐Ala‐Gly‐Lys‐Arg‐Arg‐Arg‐Gly‐Val‐Gln‐Val‐Lys‐Arg‐Arg‐Arg‐Arg‐Arg‐Arg‐Glu‐Ser‐Tyr‐Gly‐Ile‐Tyr‐Ile‐Tyr‐Lys‐Val‐Leu‐Lys‐Gln‐Val‐His‐Pro‐Asp‐Thr‐Gly‐Ile‐Ser‐Ser‐Arg‐Ala‐Met‐Ser‐Val‐Met‐Asn‐Ser‐Phe‐Val‐Asn‐Asp‐Val‐Phe‐Glu‐Arg‐Ile‐Ala‐Ala‐Glu‐Ala‐Gly‐Arg‐Leu‐Thr‐Thr‐Tyr‐Asn‐Arg‐Arg‐Ser‐Thr‐Val‐Ser‐Ser‐Arg‐Glu‐Val‐Gln‐Thr‐Ala‐Val‐Arg‐Leu‐Leu‐Leu‐Pro‐Gly‐Glu‐Leu‐Ala‐Lys‐His‐Ala‐Val‐Ser‐Glu‐Gly‐Thr‐Lys‐Ala‐Val‐Thr‐Lys‐Tyr‐Thr‐Thr‐Ser‐Arg. In a previously published partial sequence serine was incorrectly assigned to position 30.A comparison of the carboxyl‐terminal two thirds of H2B(1) Parechinus and H2Bcalf reveals that 79% of the corresponding positions are occupied by identical amino acid residues. Much of the variability occurs in a short polar region of 20 amino acid residues. The remainder of C‐terminal regions is hydrophobic and almost completely invariable.A comparison of the amino‐terminal one third of H2B(1) Parechinus and H2Bcalf reveals that they are both highly basic with a considerable homology of the position of basic amino acids. Further, H2B(1) Parechinus possesses an amino terminal extension of 19 amino acids. These 19 amino acids can be recognized as a repeating pentapeptide.

Partial amino acid sequence of histone H1 from sperm of the sea urchin, Parechinus angulosus

Partial amino acid sequence of histone H1 from sperm of the sea urchin, Parechinus angulosus

TEMPERATURE RECORDING IN SHALLOW MARINE ENVIRONMENTS

Summary The shallow inshore water masses around the Cape coast are mixed with regard to temperature and frequently experience marked fluctuations. We needed a device giving a continuous record of in situ temperature to investigate its effect on the reproductive behaviour of Parechinus angulosus Leske, a common local sea urchin. Commercial temperature recorders were enclosed in watertight housings designed for the purpose and installed on the sea-bed at the study sites.

Sequence of the cysteine-containing portion of histone F2al from the sea urchin Parechinus angulosus

FEBS LettersVolume 40, Issue 2 p. 346-348 Full-length articleFree Access Sequence of the cysteine-containing portion of histone F2al from the sea urchin Parechinus angulosus M. Strickland, M. Strickland Department of Biochemistry, University of Cape Town, Rondebosch 7700, South AfricaSearch for more papers by this authorW.N. Strickland, W.N. Strickland Department of Biochemistry, University of Cape Town, Rondebosch 7700, South AfricaSearch for more papers by this authorW.F. Brandt, W.F. Brandt Department of Biochemistry, University of Cape Town, Rondebosch 7700, South AfricaSearch for more papers by this authorC. Von Holt, C. Von Holt Department of Biochemistry, University of Cape Town, Rondebosch 7700, South AfricaSearch for more papers by this author M. Strickland, M. Strickland Department of Biochemistry, University of Cape Town, Rondebosch 7700, South AfricaSearch for more papers by this authorW.N. Strickland, W.N. Strickland Department of Biochemistry, University of Cape Town, Rondebosch 7700, South AfricaSearch for more papers by this authorW.F. Brandt, W.F. Brandt Department of Biochemistry, University of Cape Town, Rondebosch 7700, South AfricaSearch for more papers by this authorC. Von Holt, C. Von Holt Department of Biochemistry, University of Cape Town, Rondebosch 7700, South AfricaSearch for more papers by this author First published: April 01, 1974 https://doi.org/10.1016/0014-5793(74)80260-7Citations: 39AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume40, Issue2April 01, 1974Pages 346-348 ReferencesRelatedInformation

Partial amino acid sequence of two new arginine—serine rich histones from male gonads of the sea urchin ( Parechinus angulosus)

Partial amino acid sequence of two new arginine—serine rich histones from male gonads of the sea urchin ( Parechinus angulosus)

Effect of Ammonium Nitrate Solutions on Fertilization and Development of the Sea Urchin, Parechinus Angulosus

AbstractEggs and sperm of Parechinus have been placed in sea water containing 1, 10 and 100 p.p.m. ammonium nitrate and the percentage fertilization as well as the subsequent development of the embryos compared with controls. At 10 and 100 p.p.m. there is a marked reduction in fertilization. Abnormal forms are common at 100 p.p.m. and some 95% of the population fail to reach the gastrula stage.

LIFE HISTORY STUDIES ON SOUTH AFRICAN ECHINOIDS (ECHINODERMATA)

Summary A description of the laboratory rearing of Parechinus angulosus (Leske) larvae is given. The larvae are described from samples taken at intervals during the larval life history. At 15°C in the presence of autotrophic flagellates and diatoms as food, larval metamorphosis occurred 56 days after fertilization. Metamorphosis could be delayed at least eleven days in the absence of a suitable substrate.

Temporal changes in kelp forest benthic communities following an invasion by the rock lobster Jasus lalandii

The rock lobster Jasus lalandii expanded its centre of distribution south-eastwards into an area known as ‘East of Cape Hangklip’ on the south-west coast of South Africa in the early 1990s. Using historical and present data, we analysed differences in the abundance of key species and functional groups between the pre- and post-rock lobster invasion periods at two sites along that coast: Cape Hangklip and Betty's Bay. Pre-1989, lobsters were absent, but after 1995 they reached densities approximating 0.4–0.8 m−2. Benthic community composition also changed significantly with herbivores being abundant whereas macroalgae and sessile invertebrates were scarce pre-invasion. We attribute the decline of herbivores to the direct effects of lobster predation, in turn indirectly promoting macroalgae. Post-invasion sessile invertebrates and macroalgae increased by 2 600% and 453% respectively, whereas herbivores declined by 99.3%. The virtual elimination of the sea urchin Parechinus angulo-sus by rock lobsters has substantial implications for the commercial harvesting of the abalone Haliotis midae, because its juveniles are intimately associated with this urchin. The lobster invasion has thus not only led to a regime shift of the ecosystem but has also substantial economic consequences, which calls for an ecosystem approach to the management of the pool of commercially exploited resources in this region.

Studies On the Myoneural Physiology of Echinodermata

ABSTRACT The lantern retractor muscle of Parechinus angulosus responds to light stimulation by a rapid contraction which is followed by a slower increase in tension. The details of these contractions vary from preparation to preparation. With very brief light exposures only the quick response is shown, while with prolonged light stimulation rhythmical activity develops after a minute or more. Exposure of a contracting preparation to the light of a mercury vapour lamp causes a slight fall in tone. This is not due to the ultra-violet component of this light. Responses to repeated light pulses may result in simple summation or the response to the first pulse may be markedly greater than those which follow. In preparations which show this latter effect, there is evidence for an inhibitory phenomenon which persists for about 30 sec. With paired stimuli the response to the second stimulus may show an initial depression which reaches a maximum at an interval of about 10 sec., then a recovery and finally a second depression of response which is maximal when the interval between stimuli is about 5 min. There is evidence that stimulation of the comminator muscles may result in loss of tone of the lantern retractor muscles. A provisional hypothesis to explain these effects is presented.