ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1976.tb05238.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SYNOPSIS.Phylogenetic relations are ultimately determined by homologous relationships, including both structural and functional data. Following the establishment of those relationships, the direction of evolutionary change must be determined using paleontologic, developmental, and especially morphocline, data. From that perspective the direction of subsequent development becomes clearer and the problems of origins become more explicit.Using the foregoing methodology it has been possible to identify plausibly monophyletic groups of animal protists or protozoa. Allowing for attendant difficulties, there nevertheless emerges certain fairly convincing generalities: (a) the predominantly pseudopodial forms, with a few minor exceptions, have direct origins from apochlorotic algae; (b) the predominantly kinetidal forms (zooflagellates and ciliates), though also derived originally from apochlorotic algae, give evidence of extended evolutionary development with the especially noteworthy emergence of a permanent ingestatory structure; (c) both groups have increased size, a tendency towards multinuclearity and polyploidy, cytoplasmic differentiations of various sorts, and complex life cycles.In terms of further evolution, namely the emergence of multicellular animals, the pseudopodial forms are almost certainly a dead end while the kinetidal forms are arguably the ancestors of at least 2 metazoan phyla.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1976.tb05240.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SYNOPSIS.Nuclear features of dinoflagellates that were used originally to support the Mesocaryota concept are reviewed. The fibrillar diameter of dinoflagellate chromatin, low level of chromosomal basic proteins, membrane attachment of chromosomes and swirl pattern observed in sectioned chromosomes are features that support a prokaryotic affinity. The presence of repeated and highly complex DNA, a S‐phase of DNA synthesis in the cell cycle, presence of basic proteins, and the reinterpretation of extranuclear microtubules as a spindle support the contention that dinoflagellates are eukaryotes. This combination of prokaryotic and eukaryotic features suggests that dinoflagellates are a geologically old group and that perhaps they diverged from the higher eukaryotic lineage before evolution of eukaryotic chromatin but after the evolution of repeated DNA. The 2 patterns of carotenoid composition exemplified by the presence of peridinin or fucoxanthin suggest separate origins of dinoflagellate plastids, perhaps by prokaryotic and eukaryotic capture. It is suggested that the species possessing fucoxanthin obtained their plastids by capture of photosynthetic eukaryotes.A new class and order, Syndiniophyceae and Syndiniales, are proposed for the dinoflagellates with low chromosome numbers, V‐shaped chromosomes, chromosomes containing a sufficient quantity of basic proteins detectable histochemically, possession of centrioles associated with mitosis, intracellular parasitism as a mode of nutrition, and lack of a cellular covering containing plates.Ultrastructural and paleontologic evidence indicates that the thecate is more primitive than the nonthecate condition.The Prorocentrales are considered to be primitive and their thecal construction is reinterpreted as having epithecal and hypothecal regions surrounding a flagellar pore region containing 7 plates. Acritarchs resemble cysts of modern dinoflagellates in size, structure, and chemical composition except for the absence of a polygonal excystment aperture and lack of any indication of transverse and longitudinal flagellar grooves on the acritarchs. The suggestion that some acritarchs may have dinoflagellate affinities is supported by the occurrence of modern dinoflagellates (Prorocentrales) which lack a theca of numerous polygonal plates and lack transverse and longitudinal flagellar arrangement. The Prorocentrales, as opposed to the more typical Dinophyceae, perhaps represent the type of organism that produced some acritar

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1976.tb05241.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SYNOPSIS.Information relating to the ultrastructure of 4 organellar systems of flagellates—nuclei (including mitosis), flagella, mitochondria and chloroplasts—is examined for bearing on the probable phylogeny of the principal flagellate groups, first considered singly and then in combination. The mitotic mechanism has not proved to be as conservative a character as might be hoped, but still remains characteristic for the average condition in many of the groups. Flagellar features are useful if allowance is made for the reduction or multiplication of the basic pair, and the loss of lateral and terminal hairs seems to have occurred independently several times. The presence of paraxial rods within flagella may be a useful indication of affinity. Rootlet systems are not dealt with in detail here, although the possible similarity between axial microtubular sheets in axostylar flagellates and some members of the green algae containing “manchettes” is noted. The basic patterns of chloroplast internal structure are summarized and their general agreement with other characters is affirmed, noting however that cryptomonads may be closer to the green flagellates (including euglenoids) than is generally accepted. Attention is drawn to the potential value of internal mitochondrial morphology as an indicator of large assemblages. Finally, a “tree” based on multiple cell organizational features is presented an

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1976.tb05242.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1976.tb05243.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SYNOPSIS.The 16S ribosomal RNA of the chloroplast ofEuglena gracilisstrain Z has been characterized in terms of its 2‐dimensional electrophoretic “fingerprint” (T1 ribonuclease). Over 100 spots were resolved on the “fingerprint” and each spot was characterized as to which RNA oligonucleotide fragment(s) it contained. When compared to similar analyses of prokaryotic 16S rRNAs and eukaryotic cytoplasmic 18S rRNAs, the chloroplast 16S rRNA was a typically prokaryotic RNA, but bore little if any relationship to eukaryotic 18S rRNAs. Therefore, the cistrons for chloroplast 16S rRNA are related to the equivalent prokaryotic cistrons, but, apparently, are not related to the equivalent eukaryotic cistrons. Among the organisms available for comparison, theEuglenachloroplast 16S rRNA appears most closely related to the 16S rRNA of the eukaryote,Porphyridium cruentum(a red alga), and at least distantly related to the 16S rRNAs of the blue‐green algae and perhaps also to

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1976.tb05244.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SYNOPSIS.Progress in ciliatology and in allied fields may demystify ciliate phylogenetics. Concentration on hymenostomes (mainlyTetrahymenaandParamecium) may have obscured directional features of ciliate physiology in phylogenetic problems. Therefore, means are suggested for “domesticating” the presumptively primitive, predominantly marine, sand‐dwelling gymnostomes having nondividing diploid macronuclei. The prize quarry is the marine psammophileStephanopogonwhose homokaryotic condition may mark it as a living fossil. Eventual axenic cultivation of these “primitive” ciliates may be aided by use as food of easily grown photosynthetic prokaryotes, some isolated from the marine sulfuretum or adjacent aerobic muds and sands where “karyorelictid” ciliates flourish.We assume that: (a) the macronucleus evolved as a coordinator of chemical and physical signals, for efficient detection of food and toxins; (b) oral structures evolved meanwhile as sensors as well as mechanical food‐gatherers. This conjunction enabled complexity of adaptive behavior and evolutionary success. Ciliate origins cannot be considered apart from origin(s) of phagotrophy and its underlying versatile heterotrophy. Because of the well developed heterotrophy in some photosynthetic prokaryotes (including several proposed as food organisms), they are viewed as alternatives to blue‐green algae as forebears of eukaryotes. Nor can ciliate origins be considered apart from origin(s) of eukaryotes. A check of these assumptions—thatStephanopogonand gymnostomes with nondividing macronuclei are primitive—may be forthcoming from sequencing amino acids in certain key enzymes, given an adequate sampling of ciliates, flagellates (especially dinoflagellates and cryptomonads), lower fungi, and photosynthetic prokaryotes other

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1976.tb05245.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SYNOPSIS.A survey of 22 Western Painted Turtles (WPT),Chrysemys picta belliGray; 2 Map Turtles (MT),Graptemys geographicaLe Sueur; 8 False Map Turtles (FMT),Graptemys pseudogeographicaGray; 26 Illinois Mud Turtles (IMT),Kinosternon flavescens spooneriSmith; and 5 Spiny Softshell Turtles (SST),Trionyx spiniferusLe Sueur, revealed the presence of 10 species of coccidia. The species found, the shape and average length‐width dimensions (in micrometers) of their oocysts, and the respective hosts from which they were isolated were as follows:Eimeria chrysemydisDeeds&Jahn, slightly pear‐shaped (27.6 × 17.0), from 5 WPTs;Eimeria delagei marginataDeeds&Jahn, markedly pearshaped (22.1 × 17.6), from 2 WPTs, 1 MT, and 3 FMTs;Eimeria graptemydossp. n., broadly ellipsoid to subspherical (12.6 × 11.4), from 10 WPTs, 2 MTs, and 5 FMTs; Eimeria lutotestudinis sp. n., broadly ellipsoid to subspherical (11.9 × 10.8), from 4 IMTs; Eimeria mascoutini sp. n., broadly ellipsoid to subspherical with outer surface of oocyst wall mammillated (14.0 × 11.9), from 2 SSTs;Eimeria mitraria(Laveran&Mesnil), asymmetrically ellipsoid, bearing 1 or 2 conical projections at the polar end and 2 or 3 at the antipolar end (10.0 × 7.6), from 7 WPTs, 1 MT, 3 FMTs, and 4 IMTs; Eimeria pseudogeographica sp. n., narrowly ellipsoid to slightly ovoid (19.5 × 13.5), from 5 WPTs and 3 FMTs; Eimeria tetradacrutata sp. n., spherical to subspherical with outer surface of oocyst wall mammillated (19.5 × 19.2), from 1 WPT; anEimeriasp. narrowly ellipsoid, bearing 2 conical projections at the polar end and 2 at the antipolar end (23.8 × 13.2), from 1 MT; and Mantonella hammondi sp. n., conical to narrowly ellipsoid, bearing 1 conical projection at the polar end and 2 or 3 at the antipolar end (14.3 × 7.1), from 1 IMT. The overall infection rate for the 63 turtles exami

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1976.tb05246.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SYNOPSIS.By fine‐structural studies of speculation stages in the European flat oyster pathogenMarteilia refringensthis organism is shown to be a member of the protozoan class Haplosporea. This conclusion is based on observations that haplosporosomes are found in plasmodia and spores and that sporoplasm delimitation occurs by internal cleavage within plasmodia. During sporulation plasmodia become sporangiosori by enlarging, cleaving internally into ∼ 8 sporangia, each of which then cleaves internally into 3 or 4 spore primordia. The primordia divide into 3 uninucleate sporoplasms of graded sizes, the smallest lying in an eccentrically located vacuole of the medium‐sized one, and the latter situated within an eccentric vacuole of the largest. Haplosporosomes are found only in the cytoplasm of the largest sporoplasm. Mature, living spores measure 3.9(3.5–4.5)μm diameter and are enclosed in a continuous wall without a mantle of epispore cytoplasm as in other Haplosporea.An amended genus and species description ofMarteilia refringensis presented, based on light and electron microscope obse

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1976.tb05247.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SYNOPSIS.An extracellular surface coat was observed at the fine‐structural level on the outer lamina of the pellicular and flagellar membranes of intactTrypanosoma musculibloodstream forms. The surface coat had a mean width of 9.2 nm, and was composed of a somewhat electron dense, uneven, fibrillar‐like matrix. Brief trypsin treatment of living blood forms completely removed the cell surface coat.Several cytochemical methods applicable to electron microscopy were used to detect the presence and distribution of carbohydrates in the trypanosome's surface coat and pellicular membrane. The polycationic dye compounds employed were: ruthenium red, ruthenium violet, Alcian blue chloride, and lanthanum nitrate. Electron‐dense stain reaction products, indicative of polysaccharides, were evident in the surface coat of cells treated with these dyes, which also agglutinated both living and glutaraldehyde fixed cells. Like the surface coat, the pellicular membrane of trypsinized cells gave strong positive staining reactions with the several dyes, indicating the presence of membrane bounded carbohydrates, and living and glutaraldehyde‐fixed trypsinized cells were agglutinated with the polycationic stains. Bloodstream forms were treated with the enzymes, α‐amylase, dextranase, and neuraminidase. No obvious morphologic difference, however, was apparent between the surface coat of untreated cells and those subjected to treatment with any of the various glycoside hydrolase enzymes. Further, these enzymes had no apparent gross effect on the staining affinity of the surface coat for the several polycationic dyes. Cationized ferritin was used to visualize the negative cell surface charge ofT. musculibloodstream forms. Large quantities of cationized ferritin were bound in the surface coat matrix. Glycoside hydrolase enzyme treatments had no apparent effect on the amount of ferritin bound in the surface coat. Cationized ferritin was bound also to the outer lamina of the pellicular membrane in trypsinized cells, which had quantitatively less ferritin bound per surface unit area than bloodstream forms untreated by the enzyme. Living and glutaraldehyde‐fixed cells were agglutinated with cationized ferritin. The results obtained in the various experiments indicated that polyanionic polysaccharides were constituent terminal ligands of the surface coat matrix and pellicular membrane inT. musculiblood

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1976.tb05248.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY