The Biological bulletin最新文献_第10页

Development, Temperature Tolerance, and Settlement Preference of Embryos and Larvae of the Articulate Brachiopod Laqueus californianus. 齿形腕足动物加利福尼亚湖鳗胚胎和幼虫的发育、耐温性和沉降偏好。

IF 1.6

The Biological bulletin Pub Date : 1999-06-01 DOI: 10.2307/1542949

J T Pennington, M N Tamburri, J P Barry

{"title":"Development, Temperature Tolerance, and Settlement Preference of Embryos and Larvae of the Articulate Brachiopod Laqueus californianus.","authors":"J T Pennington, M N Tamburri, J P Barry","doi":"10.2307/1542949","DOIUrl":"https://doi.org/10.2307/1542949","url":null,"abstract":"Populations of the articulate brachiopod Laqueus californianus occur in dense single-species aggregations near the continental shelf/slope break (100-200 m) in Monterey Bay, California. The development of embryos and larvae of L. californianus has been examined by scanning electron microscopy. Fertilizable eggs are 130-140 {mu}m in diameter, and sperm are unmodified. Cleavage is holoblastic and radial. At 10{deg}C an up-swimming blastula develops by 18-h, and gastrulation occurs within 24-38 h. The embryo elongates on a new larval axis and the blastopore closes by 72 h. A trilobed articulate brachiopod larva forms by day 3-4, and a metamorphically competent larva with attachment disk is attained in 7 days. Competent larvae swim downwards. Effects of temperature on larval survival and development rate have also been examined. Larvae die within 1 day at 25{deg}C. At 20{deg}C, development appears normal but results in spontaneous abnormal settlement of larvae 5-6 days old. At 15{deg}, 10{deg}, and 5{deg}C, most larvae achieve competence in 5, 7, and 9 days, respectively. Many larvae survive for 71 days at 10{deg} and 15{deg}C. Patterns of larval settlement vary among substrates, but larvae show strong preference for shells of living conspecific adults. Settlement and metamorphosis can occur within 24 h upon exposure of larvae to substrate.","PeriodicalId":153307,"journal":{"name":"The Biological bulletin","volume":" ","pages":"245-256"},"PeriodicalIF":1.6,"publicationDate":"1999-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1542949","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34814694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 34

Zooflagellate Phylogeny and the Systematics of Protozoa. 鞭毛虫系统发育与原生动物分类学。

IF 1.6

The Biological bulletin Pub Date : 1999-06-01 DOI: 10.2307/1542978

T Cavalier-Smith

引用次数: 13

Intracapsular Feeding by Embryos of the Gastropod Genus Littorina. 小腹足动物属胚胎的囊内摄食。

IF 1.6

The Biological bulletin Pub Date : 1999-06-01 DOI: 10.2307/1542948

A L Moran

{"title":"Intracapsular Feeding by Embryos of the Gastropod Genus Littorina.","authors":"A L Moran","doi":"10.2307/1542948","DOIUrl":"https://doi.org/10.2307/1542948","url":null,"abstract":"Many gastropod species develop within egg capsules within which larvae are provided with extraembryonic nutrients. Species with encapsulated development frequently have transitory embryonic organs, such as \"larval kidneys,\" that may represent specializations for consumption of intracapsular nutrition. Larvae of Littorina species with nonplanktonic, encapsulated development consume intracapsular albumen, but they lack obvious morphological modifications for albumen consumption. To determine the mechanism and location of protein uptake, larvae of seven species of Littorina (L. keenae, L. littorea, L. plena, L. saxatilis, L. scutulata, L. sitkana, L. subrotundata) were exposed to solutions of either fluorescently labeled protein (FITC-bovine serum albumen) or ferritin. Under fluorescence microscopy, larvae of all species with encapsulated, nonplanktonic development displayed strong regional affinity for FITC in the ciliated cells of the velum, whereas hatched larvae of planktotrophic Littorina species did not. Transmission electron microscopy of epithelial cells of nonplanktotrophic veligers exposed to ferritin supported the interpretation that localized affinity for labeled protein indicated endocytotic protein uptake. Planktotrophic Littorina and Littorina with encapsulated, nonplanktonic development were shown to share equivalent velar width/larval length ratios during early embryonic development, whereas a literature search suggested that in other nonplanktotrophic prosobranchs the velum is relatively smaller than in planktotrophs. Retention of a large velum in Littorina that develop entirely within egg capsules may facilitate feeding on intracapsular protein, in the absence of specialized assimilative organs found in other species with encapsulated development.","PeriodicalId":153307,"journal":{"name":"The Biological bulletin","volume":" ","pages":"229-244"},"PeriodicalIF":1.6,"publicationDate":"1999-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1542948","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34814693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 53

Patterns of Mitochondrial DNA Strand Asymmetry Correlate With Phylogeny. 线粒体DNA链不对称模式与系统发育相关。

IF 1.6

The Biological bulletin Pub Date : 1999-06-01 DOI: 10.2307/1542983

S Mohr, J Freeman, T Plasterer, T Smith

{"title":"Patterns of Mitochondrial DNA Strand Asymmetry Correlate With Phylogeny.","authors":"S Mohr, J Freeman, T Plasterer, T Smith","doi":"10.2307/1542983","DOIUrl":"https://doi.org/10.2307/1542983","url":null,"abstract":"In the current era of megabase DNA sequencing, there is a need for analytical methods that extend beyond the level of single genes or gene clusters and allow us to characterize genome features more globally. Following up on the observations of Lobry (1, 2) concerning “GC skew” [relative enhancement of G in one strand over a given DNA segment: (G C)/(G + C)], we have begun to examine “purine excess” in long DNA sequences. This function-defined as the sum of all purines minus the sum of all pyrimidines encountered in a sequence up to the given position-displays the overall strand asymmetry. In bacterial genomes, the minima and maxima of the purine excess curves correlate closely with, respectively, the origins and termini of replication (3). We have now calculated the purine-excess curves for 52 complete mitochondrial DNA sequences available from GenBank. They cover the entire range of eukaryotes, from yeast to human, and display intriguing patterns that correlate with phylogenetic relationships. The curves for closely related organisms (e.g., sets of primates, pinnipeds, marsupials, fish, insects, or sea urchins) virtually superpose, whereas curves from more distant heterogeneous groups (e.g., crustaceans plus insects) have recognizable similarities, but also clear differences of detail. Characteristically, the larger “ancestral” mtDNAs from single-celled organisms have “choppier” curves (see Fig. 1) with many sharp peaks and troughs, whereas the curves become smoother as one advances to the vertebrates with their “derived” mtDNAs of about 15 kb. Over the range from Latimeria to Homo-including 29 species-the purine ex-","PeriodicalId":153307,"journal":{"name":"The Biological bulletin","volume":" ","pages":"411-412"},"PeriodicalIF":1.6,"publicationDate":"1999-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1542983","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34814690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

A Genomics Approach to Mitochondrial Evolution. 线粒体进化的基因组学方法。

IF 1.6

The Biological bulletin Pub Date : 1999-06-01 DOI: 10.2307/1542980

M W Gray, G Burger, R Cedergren, G B Golding, C Lemieux, D Sankoff, M Turmel, B F Lang

引用次数: 4

Phylogenetic Position of Amitochondriate Protists in the Evolution of Eukaryotes. 真核生物进化中线粒体原生生物的系统发育地位。

IF 1.6

The Biological bulletin Pub Date : 1999-06-01 DOI: 10.2307/1542977

M Hasegawa, T Hashimoto

引用次数: 2

The Molecular Tangled Bank: Not Seeing the Phylogenies for the Trees. 分子缠绕的河岸:没有看到树木的系统发育。

IF 1.6

The Biological bulletin Pub Date : 1999-06-01 DOI: 10.2307/1542984

L Margulis, M Dolan, R Guerrero

引用次数: 3

Rethinking the Origin of Eukaryotes. 重新思考真核生物的起源。

IF 1.6

The Biological bulletin Pub Date : 1999-06-01 DOI: 10.2307/1542974

W F Doolittle

引用次数: 6

The Effect of Secondary Loss on Our Views of Eukaryotic Evolution. 次生损失对真核生物进化观点的影响。

IF 1.6

The Biological bulletin Pub Date : 1999-06-01 DOI: 10.2307/1542976

C G Clark

{"title":"The Effect of Secondary Loss on Our Views of Eukaryotic Evolution.","authors":"C G Clark","doi":"10.2307/1542976","DOIUrl":"https://doi.org/10.2307/1542976","url":null,"abstract":"Traditionally, phylogenetic relationships among eukaryotes have been inferred using morphological information. In prokaryotes, morphology is not very useful for this purpose and other approaches have been preferred. The morphological bias among those of us who study eukaryotes has led us into a number of traps. Even with the advent of molecular sequence data, we have failed to break some of our bad habits in interpreting phylogenetic trees. The common false assumption, in all its guises, can be boiled down to one phrase-simple equals primitive. The fundamental flaw that has been ignored time and time again is that simple can also mean derived. Misinterpreting the absence of a character as a sign of an organism’s primitive nature often results in a false view of eukaryotic evolution. Secondary loss is a pervasive characteristic of eukaryotic evolution. Parasites appear to be particularly susceptible to secondary simplification or loss of structure. This can be illustrated from our studies of the evolution of eukaryotic organelles. A popular choice as paradigm for the ancestral eukaryote, especially among those who worked with the organism, was for many years Entamoeba histolytica, the agent of amoebic dysentery. This organism lacks many typical eukaryotic features-mitochondria, Golgi apparatus, flagella, rough endoplasmic reticulum-and has other unusual characteristics that could be interpreted as primitive. However, when ribosomal RNA-based phylogenetic trees that included Entamoeba species became available, the branch leading to these organisms was not basal to other eukaryotes, as had","PeriodicalId":153307,"journal":{"name":"The Biological bulletin","volume":" ","pages":"385-388"},"PeriodicalIF":1.6,"publicationDate":"1999-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1542976","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34814699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Physiological Functioning of Carbonic Anhydrase in the Hydrothermal Vent Tubeworm Riftia Pachyptila. 热液喷口管虫碳酸酐酶的生理功能。

IF 1.6

The Biological bulletin Pub Date : 1999-06-01 DOI: 10.2307/1542950

S K Goffredi, P R Girguis, J J Childress, N T Desaulniers

{"title":"Physiological Functioning of Carbonic Anhydrase in the Hydrothermal Vent Tubeworm Riftia Pachyptila.","authors":"S K Goffredi, P R Girguis, J J Childress, N T Desaulniers","doi":"10.2307/1542950","DOIUrl":"https://doi.org/10.2307/1542950","url":null,"abstract":"On the basis of our experiments, it is clear that carbonic anhydrase (CA) plays an important role in the CO2-concentrating mechanisms in Riftia pachyptila. Plume tissue from freshly collected animals had the highest CA activity, 253.7 +/- 36.0 {mu}mol CO2 min-1 g-1 wet wt, and trophosome activity averaged 109.4 +/- 17.9 {mu}mol CO2 min-1 g-1 wet wt. Exposure of living worms to ethoxyzolamide, a carbonic anhydrase inhibitor, resulted in a 99% decrease in CA activity (from 103.9 +/- 38.6 to 0.7 +/- 0.2 {mu}mol CO2 min-1 g-1 wet wt in the plume tissue and 57.6 +/- 17.9 to 0.04 +/- 0.11 {mu}mol CO2 min-1 g-1 wet wt in the trophosome) and essentially a complete cessation of {Sigma}CO2 uptake. High concentrations of CA appear to facilitate the equilibration between inorganic carbon (Ci) in the external and internal environments, greatly enhancing the diffusion of CO2 into the animal. In summary, R. pachyptila demonstrates very effective acquisition of inorganic carbon from the environment, thereby providing the symbionts with large amounts of CO2. This effective acquisition is made possible by three factors: extremely effective pH regulation, a large external pool of CO2, and, described in this paper, high levels of carbonic anhydrase.","PeriodicalId":153307,"journal":{"name":"The Biological bulletin","volume":" ","pages":"257-264"},"PeriodicalIF":1.6,"publicationDate":"1999-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2307/1542950","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34814695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 29