COLACIUM LIBELLAE SP. NOV. (EUGLENOPHYCEAE), A PHOTOSYNTHETIC INHABITANT OF THE LARVAL DAMSELFLY RECTUM1

Colacium libellae sp. nov., in the non-flagellated palmella stage and lacking stalks, lines the cuticle of the rectum of damselfly larvae, forming a conspicuous green plug. In culture this species forms highly-branched colonies of stalked cells. The cells tire often elongated to twice the size of most motile cells (40–50 × 6–10 μm), with parallel sides and rounded apices. These features are distinctive when comparisons are made among clones of related species in soil-water-pea medium. C. libellae established itself in the rectum of previously Colacium-free larvae of the damsel fly Anomalagrion hastatum whereas a clone of C. vesiculosum and C. mucronatum did not.     

COLONIZATION AND REPRODUCTION OF THE EPIBIOTIC FLAGELLATE COLACIUM VESICULOSUM (EUGLENOPHYCEAE) ON DAPHNIA PULEX1

The epibiotic flagellate Colacium vesiculosum Pringsheim attaches to planktonic species of Daphnia in freshwater habitats. Previous studies found that prevalence (percentage of substrate organisms carrying attached epibionts) and intensity (number of attached epibionts on a given substrate organism) are low early in the Daphnia intermolt period and are high late in the intermolt period. We tested the hypothesis that increases of Colacium cells attached to Daphnia occur both by rapid initial and continuous colonization and by cell reproduction. Epibiont prevalence and intensities were determined at successive intermolt stages of Daphnia pulex Leydig collected from freshwater ponds in Colorado. Colonization was continuous throughout the intermolt period and was most important to epibiont population increase at the beginning of the intermolt period. Cell division was the major contributor to epibiont increase at the end of the intermolt period.     

Tracing Patterns of Chloroplast Evolution in Euglenoids: Contributions from Colacium vesiculosum and Strombomonas acuminata (Euglenophyta)

The chloroplast genomes of two photosynthetic euglenoids, Colacium vesiculosum Ehrenberg (128,889 bp), and Strombomonas acuminata (Schmarda) Deflandre (144,167 bp) have been sequenced. These chloroplast genomes in combination with those of Euglena gracilis, Eutreptia viridis, and Eutreptiella gymnastica provide a snapshot of euglenoid chloroplast evolution allowing comparisons of gene content, arrangement, and expansion. The gene content of the five chloroplast genomes is very similar varying only in the presence or absence of, rrn5, roaA, psaI, psaM, rpoA, and two tRNAs. Large gene rearrangements have occurred within the C. vesiculosum and S. acuminata chloroplast genomes. Most of these rearrangements represent repositioning of entire operons rather than single genes. When compared with previously sequenced genomes, C. vesiculosum and S. acuminata chloroplast genomes more closely resemble the E. gracilis chloroplast genome in size of the genome, number of introns, and gene order than they do those of the Eutreptiales. Overall, the chloroplast genomes of these five species show an evolutionary trend toward increased intron number, a decrease in gene density, and substantial rearrangement of gene clusters.     

Seasonal dynamic of phototrophic epibionts on crustacean zooplankton in a eutrophic reservoir with cyanobacterial bloom

Seasonality of burden and prevalence of phototrophic (microalgal) epibionts Characidiopsis ellipsoidea, Colacium vesiculosum and Colacium sp. on dominating crustacean zooplankton (Daphnia longispina, Cyclops vicinus and Mesocyclops leuckarti) were studied in a small reservoir Bugach with cyanobacterial bloom. The correlations between the seasonal dynamics of prevalence and the dynamics of others biotic and abiotic factors were calculated. The conclusions were as follows. The substrate species, that determined the development of the epibionts on the three studied crustacean zooplankton, was Daphnia longispina (Cladocera). Despite intensive epibiotic infestation of crustacean zooplankton, epibionts did not appear to have caused non-consumptive mortality of the crustacean zooplankton. But they could have contributed to the Daphnia summer decline by increasing mortality due to its consumption by planktivorous fishes. The phototropic epibionts may successfully coexist with cyanobacterial bloom. The possible role of the epibionts in changing nutrient fluxes in pelagic food web is discussed.     

THE MORPHOLOGY AND DEVELOPMENT OF SOME PROMINENTLY STALKED SOUTHERN AUSTRALIAN HALYMENIACEAE (CRYPTONEMIALES,RHODOPHYTA). I. CRYPTONEMIA KALLYMENIOIDES (HARVEY) KRAFT COMB. NOV. AND C. UNDULATA SONDER1

Several southern Australian red algae of the family Halymeniaceae (Cryptonemiales) are differentiated into hard, massive stalks and considerably softer laminar blades or phyllodes. The taxonomy, morphology and pit-connection ultrastructure of one such species, Cryptonemia kallymenioides (Harvey) Kraft comb. nov., are compared to C. undulata Sonder, which lacks massive stalks. In both species there is extensive periodic secondary cortication of the stalks, resulting in the formation of distinct “growth rings.” The blades of C. kallymenioides appear to be seasonal and its stalks perennial, while plants of C. undulata are apparently perennial but shorter lived than C. kallymenioides. As a result, stalks in the latter can reach 2–3 cm in diameter with up to 18 growth rings, compared to the 1–2 mm diameters and up to 6 rings within the stalks of C. undulata. Heavy secondary thickening of cortical cell walls occurs in both species and confers a “woody” texture to the stalks of C. kallymeniodes. Regardless of the large differences in average stalk diameters between the two species, the pit-connection ultrastructure from cortex to medulla shows much the same sequence of morphological modification. Pit-connections are standard red algal structures in the outer cortex, but become increasingly convoluted on the membrane-bound surfaces abutting cytoplasm and develop wider apertures and less dense cores with increasing distance from the stalk surface. In occasional medullary cells of C. kallymenioides, the cytoplasm disintegrates, leaving cell walls and pit-connections to play an apparently structural role which has not been reported in other red algae. It is suggested that the increase in aperture size and surface areas of pit-connections is compatible with their playing a role in the intercellular transport of solutes towards the inner cell layers which may, in C. kallymenioides, lie many millimeters distant.     

THE MORPHOLOGY AND DEVELOPMENT OF SOME PROMINENTLY STALKED SOUTHERN AUSTRALIAN HALYMENIACEAE (CRYPTONEMIALES,RHODOPHYTA). II. THE SPONGE-ASSOCIATED GENERA THAMNOCLONIUM KUETZING AND CODIOPHYLLUM GRAY1

Three members of the red algal family Halymeniaceae (Thamnoclonium dichotomum (J. Ag.) J. Ag., Codiophyllum flabelliforme (Sond.) Schmitz, and C. decipiens (J. Ag.) Schmitz) are investigated. All are endemic to southern and southwestern Australia, possess basal stalks of substantial size and firmness, and are consistently associated with specific sponge taxa. In each case, the sponges are bonded by collagen-like fibrils to the host cuticle without modifying the algal tissue at the ultrastructural level. Secondary cortication and prominent growth rings occur in the stalks of all three species, and in each the pit plugs between cells become wider, more convoluted and less electron dense with increasing distance from the surface. Such pit plugs are apparently a unique attribute of the stalked Halymeniaceae. The three species share pit plug, sponge association and stalk morphological features but are not otherwise closely related, as they actually represent three distinct genera.     

NUTRITIONAL STUDIES ON THE CHLOROMONADOPHYCEAE: VACUOLARIA VIRESCENS AND GONYOSTOMUM SEMEN12

Unialgal, nonaxenic cultures of Vacuolaria virestcens Cienkowsky were grown in soil-water medium, in simple salt solutions with added peat and soil extract, and in synthetic medium. Doubling times in different media were determined: maximum growth rate (doubling time = 46.0 hr) was obtained in continuous light (210 ft-c) at 24 ± I C. Gonyostomum semen (Ehrenberg) Diesing was isolated from a natural population and grown in soil-water medium and a synthetic medium. Other techniques that have been used for culturing chloromonadophycean algae are reviewed.     

SPORE FORMATION IN THE LIFE CYCLES OF THE DIATOMS CHAETOCEROS DIADEMA AND LEPTOCYLINDRUS DANICUS1

A nitrogen limitation technique elicited the entire life cycle of the marine centric diatoms Chaetoceros diadema (Ehr.) Gran and Leptocylindrus danicus Cleve. In C. diadema the sexual cycle followed the same pattern as in the previously investigated C. didymus. Sexuality took place in narrow diameter cells, only at 2 and 5° C, and was seldom seen. Resting spore formation took place in cells of all sizes and at all temperatures at which the species grew vegetatively (2–15° C). The L. danicus life cycle is probably unique among diatoms. Nitrogen depletion induced sexuality in the entire culture at 10 and 15° C if the cell diameter was narrow (3–8 μm). Auxospore formation was followed by resting spore formation directly within the auxospore. In C. diadema, as in most centric diatoms, resting spores are not an obligate part of the life cycle, but they are in L. danicus. Resting spore formation is a versatile adaptive response in C. diadema, depending only on nitrogen depletion, although promoted by low temperatures. In L. danicus the linkage to the sexual process sharply limits conditions under which resting spores can form.     

EFFECTS OF BROMIDE AND IODIDE ON STALK SECRETION IN THE BIOFOULING DIATOM ACHNANTHES LONGIPES (BACILLARIOPHYCEAE)1

Extracellular polymeric substance (EPS) secretion was examined in the stalked marine diatom Achnanthes longipes Ag. in defined medium. This common biofouling diatom exhibited an absolute requirement for bromide for stalk production and substratum attachment, whereas elevated iodide concentrations in the growth medium inhibited stalk formation and adhesion. Varying EPS morphologtes resulted from altering bromide and iodide levels: pads, stalk-pads, stalks, and no EPS. Cells showed no differences in growth with bromide or iodide concentrations, indicating that they were not physiologically stressed under conditions that impaired EPS secretion. Cells grown in elevated iodide secreted significantly more soluble extracellular carbohydrate into the medium, suggesting that the EPS was soluble and unable to be polymerized into a morphologically distinct gel. By replacing sulfate with methionine, the diatom lost its ability to form stalks even in the presence of bromide, indicating that free sulphate may be required for proper cross-linking of stalk polymers. Lotus-FITC, a fluorescent-tagged lectin, preferentially labeled the EPS and, thus, was used to visualize and quantify EPS secretion along a bromide gradient in conjunction with an image analysis system. This technique demonstrated a direct correlation between the amount of bromide present in the medium and the specific EPS morphology formed.     

In vitro culture and somatic embryogenesis of four Trifolium species

Callus cultures were induced from hypocotyl sections of Trifolium incarnatum L., T. vesiculosum Savi., T. ambiguum Bieb., and T. repens L. Callus production was the greatest for T. incarnatum and T. ambiguum on Phillips and Collins L2 medium with 0.06 mg/l picloram and 0.1 mg/l 6-benzylaminopurine and for T. vesiculosum and T. repens on Gamborg B5 medium with 1.25 mg/l 2,4-dichlorophenoxyacetic acid (2.4-D), 0.5 mg/l naphthaleneacetic acid (NAA), and 0.5 mg/l 6-furfurylaminopurine (kinetin). Proembryos or somatic embryos were formed in all four species though germination and subsequent plantlet formation only occured in t. incarnatum and T. vesiculosum. Mature plants were obtained via somatic embryogenesis for T. incarnatum. The regenerated plants were fertile and had the normal diploid number of chromosomes (2n = 14).     

Relationships between height and girth of mangroves and soil-water conditions in the Mary and Hawkesbury River estuaries,eastern Australia

Abstract The height and diameter at breast height (DBH) of mangroves on the Hawkesbury River, New South Wales and the Mary River, Queensland were related to soil-water salinity, soil-water content and distance from the mouth of the estuary. On the Hawkesbury River, both Avicennia marina and Aegiceras corniculatum declined in height and DBH with increasing soil-water salinity and soil-water content, and increased in height with distance from the mouth of the estuary. Both species showed an extensive range of all variables. On the Mary River, where species diversity was higher, no relationship was found between the height and DBH of A. marina and A. corniculatum and soil-water salinity and soil-water content. Both species increased in height with increasing distance from the mouth of the estuary, a characteristic shared with all other species studied (Excoecaria agallocha, Ceriops tagal var. australis, Rhizophora stylosa). The results suggest that growth characteristics of mangroves are not a simple response to salinity gradients in diverse systems and that other variables such as nutrient availability may be important controls on mangrove growth.     

COPROMYXELLA: A NEW GENUS OF ACRASIDAE

A new genus of cellular slime molds, Copromyxella, is described together with four species that comprise it. Since it resembles Zopf's Copromyxa more than any genus presently recognized, but differs from it in important characteristics such as the smaller dimensions of its cellular elements and the delicacy of its fructifications, the name Copromyxella is chosen for the new taxon. Four species are included: C. silvatica, C. filamentosa, C. spicata, and C. coralloides. All are characterized by small myxamoebae with lobose and potentially “explosive” pseudopodia and may assume limax forms in liquid media; all possess nuclei with centrally positioned nucleoli; all lack true contractile vacuoles (with a single possible exception); all aggregate without stream formation; and all form fructifications with no demarcation into stalks and sori. Taxonomically the genus belongs in the Acrasidae with Copromyxa, Guttulinopsis and Acrasis rosea rather than in the better known Dictyostelidae that includes Dictyostelium and Polysphondylium.     

PHYLOGENY OF THE EUGLENALES INFERRED FROM PLASTID LSU rDNA SEQUENCES1

To gain insights into the phylogeny of the Euglenales, we analyzed the plastid LSU rDNA sequences from 101 strains of the photosynthetic euglenoids belonging to nine ingroup genera (Euglena, Trachelomonas, Strombomonas, Monomorphina, Cryptoglena, Colacium, Discoplastis, Phacus, and Lepocinclis) and two outgroup genera (Eutreptia and Eutreptiella). Bayesian and maximum‐likelihood (ML) analyses resulted in trees of similar topologies and four major clades: a Phacus and Lepocinclis clade; a Colacium clade; a Trachelomonas, Strombomonas, Monomorphina, and Cryptoglena clade; and a Euglena clade. The Phacus and Lepocinclis clade was the sister group of all other euglenalian genera, followed by Discoplastis spathirhyncha (Skuja) Triemer and the Colacium clade, respectively, which was inconsistent with their placement based on nuclear rDNA genes. The Trachelomonas, Strombomonas, Monomorphina, and Cryptoglena clade was sister to the Euglena clade. The loricate genera, Trachelomonas and Strombomonas, were closely related to each other, while Monomorphina and Cryptoglena also grouped together. The Euglena clade formed a monophyletic lineage comprising most species from taxa formerly allocated to the subgenera Calliglena and Euglena. However, within this genus, none of the subgenera was monophyletic.     

BIOMINERALIZATION OF THE STALKS OF ANTHOPHYSA VEGETANS (CHRYSOPHYCEAE)1

Mineralized stalks of the chryophyte Anthophysa ve-getans (O. F. Müller) Stein were examined by electron microscopy, and the composition of the stalks was determined by energy dispersive x-ray microanalysis. Colonies grown in water from a local lake (Dowdy Lake) had mineralized stalks that were colorless and composed mainly of spherules of calcium phosphate up to 0.7 μm in diameter. The addition of 0.1 mM MnCl₂ to the culture medium resulted in deeply orange-brown stalks mineralized primarily with minute granules of a manganese compound. The addition of 0.1 mM FeCl₃ to the culture media resulted in light yellow stalks mineralized mainly with small granules of an iron compound. The addition of 0.1 mM MgCl₂ or KCl resulted in stalks that were similar in appearance and composition to the colonies grown in culture medium alone. These results show that the composition of the mineralized stalks of A. vegetans is dependent on the elements present in the culture medium. This is also the first time that calcium phosphate has been reported as a mineralization product in the chrysophytes.     

BIOTIC RELATIONSHIPS BETWEEN SOIL ALGAE AND OTHER MICROORGANISMS

Parker , Bruce C., and Harold C. Bold . (U. Texas, Austin.) Biotic relationships between soil algae and other microorganisms. Amer. Jour. Bot. 48(2): 185–197. Illus. 1961.—A study was conducted of biotic relationships between various algae and other microorganisms isolated from a sample of Texas soil. From 143 two-membered combinations of organisms tested in soil-water cultures, 3 were selected for detailed studies of the nature of the causal mechanisms of the associative effects. These were: (1) an association between a species of Bracteacoccus (Br. A-20) and a heterotrophic bacterium (B-6); (2) an association between a species of Chlamydomonas (Ch. 10) and a species of Streptomyces (Act-1); and (3) an association between a blue-green alga, Phormidium sp. (Ph. 14), and an as-yet-unidentified fungus (F-2). In the first association, the heterotrophic bacterium increased growth of Bracteacoccus up to 20 times in soil-water culture; the chief cause of stimulation was shown by a series of experiments to be the decomposition by the bacterium of complex nitrogenous substrates in the soil resulting in the release of simplified products which were available to the alga as a nitrogen source. In soil-water culture, Streptomyces (Act-1) enhanced the growth and motility of Chlamydomonas (Ch. 10) and induced akinetogenesis in the alga, while the actinomycete itself was stimulated in growth and production of conidia. The mutual stimulation was shown to be caused, in part, by carbon dioxide-oxygen interchange between the organisms. Motility of Ch. 10 was enhanced by a decrease in nitrogen as a result of the growth of Act-1 and by the ability of Act-1 to decompose and assimilate the extracellular polysaccharide of the alga. The assimilation of the extracellular polysaccharide by the actinomycete promoted its growth and conidia production. Initiation of akinetogenesis in Chlamydomonas occurred exclusively in close association with the filaments of Streptomyces in soil-water cultures, and only when the concentration of available nitrogen dropped below a critical level. The akinetogenic factor has not yielded to isolation and identification, but there is some suggestion that it may be an antibiotic substance. Phormidium (Ph. 14) was frequently antagonized and annihilated by fungus 2 in the soil-water medium. Attempts to extract growth inhibitors from filtrates of the fungal medium were unsuccessful. Indirect evidence suggested that perhaps the consumption of extracellular polysaccharide with concomitant release of organic acid by the fungus might be the factor inhibiting growth of Phormidium. Attempts to confirm experimentally the ecological significance for these biotic relationships are reported.     

武汉东湖柄裸藻(Colacium Ehr.)的研究——1.形态和分类

近几年来,在武汉东湖,每到深秋至次年初夏都出现数量较多,主要附生在枝角类和桡足类等浮游动物体表的柄裸藻属(Colacium Ehr.)植物;在冬末春初,出现种群数量的高峰。自1981年至1984年,作者曾对它进行过有关形态、分类和生态方面的探讨。在本文仅简述其有关形态和分类方面的问题。     

Precipitin studies for the identity of antigens in different species of Sporotrichum

Summary 1) A simple technique for the preparation of dissolved autoclaved antigens and of sonic vibrated antigens, the immunisation of rabbits, and testing methods by precipitation in agar medium and in capillary tubes are described.2) Five different strains ofSporotrichum belonging to three species,S. Schenckii, S. Beurmanni, andS. asteroides are studied as to their precipitin lines formation in agar medium.3) The similarity in precipitin lines formation is interpreted to demonstrate the antigenic identity of these differentSporotrichum species.4) Comparable results with minor differentiation but in major sensitivity are obtained by precipitin tests in capillary tubes.5) Temperatures of 4° C are shown to stimulate intensity of precipitin lines.6) Dissolved sonic vibrated antigens alter the precipitin formation by changing and intensifying the precipitin lines.7) Absorption experiments with dissolved antigens give unsatisfactory results if precipitin tests in capillary tubes are used.This work was done during a Fulbright Fellowship spent with Dr.Norman F. Conant, Department of Bacteriology, Duke University School of Medicine, Durham, N.C.     

THE RESERVOIR CYTOSKELETON AND A POSSIBLE CYTOSTOMAL HOMOLOGUE IN COLACIUM (EUGLENOPHYCEAE)1

The reservoir cytoskeleton of Colacium Ehrenberg is formed of three bands of microtubules. The microtubules of the dorsal band (DMT) become doublets and are continuous with the longitudinal microtubules of the canal and, therefore, of the pellicle. A band of para-reservoir microtubules (PMT) acts as a linkage between the edges of the dorsal band at the formation of the canal. The third band of microtubules (MTR), more ventral, branches away from the reservoir-canal transition region and forms a supportive band for a pocket formed from the reservoir membrane. The outer part of the pocket membrane is closely invested with a fibrillar mesh. The pocket of Colacium, a green euglenoid, resembles structurally the cytopharynx of the colorless phagotrophic euglenoids, Isonema papillatum and the bodonid flagellates. The homologies support the hypothesis of euglenoid derivation from the kinetoplastid flagellates.     

THE DEVELOPMENT OF CELLULAR STALKS IN BACTERIA

Extensive stalk elongation in Caulobacter and Asticcacaulis can be obtained in a defined medium by limiting the concentration of phosphate. Caulobacter cells which were initiating stalk formation were labeled with tritiated glucose. After removal of exogenous tritiated material, the cells were subjected to phosphate limitation while stalk elongation occurred. The location of tritiated material in the elongated stalks as detected by radioautographic techniques allowed identification of the site of stalk development. The labeling pattern obtained was consistent with the hypothesis that the materials of the stalk are synthesized at the juncture of the stalk with the cell. Complementary labeling experiments with Caulobacter and Asticcacaulis confirmed this result. In spheroplasts of C. crescentus prepared by treatment with lysozyme, the stalks lost their normal rigid outline after several minutes of exposure to the enzyme, indicating that the rigid layer of the cell wall attacked by lysozyme is present in the stalk. In spheroplasts of growing cells induced with penicillin, the stalks did not appear to be affected, indicating that the stalk wall is a relatively inert, nongrowing structure. The morphogenetic implications of these findings are discussed.     

Evolution of female mating preferences in stalk-eyed flies

Sensory exploitation predicts that female mate preferences existbefore the evolution of exaggerated male ornaments. We testedthis prediction by estimating female preference functions, rematingintervals, and copulation durations for three species of stalk-eyedflies. Two species, Cyrtodiopsis whitei and C dalmanni, exhibitextreme sexual dimorphism in eye span, with eye stalks exceedingbody length in large males. In contrast, C quinqucguttata ofboth sexes possess short eye stalks. Maximum parsimony analysisof 437 basepairs of the 16S mitochondrial ribosomal RNA genefrom 6 Malaysian diopsids reveals that short, sexually monomorphiceye stalks are plesiomorphic in Cyrtodiopsis. Observations ofmultiple copulations by females in paired-choice mating chambersindicated that female C whitei and C. dalmanni exhibit relativepreferences for longer eye stalks such that preference intensityincreases linearly with the difference in eye stalk length betweenmales. Females from the sexually monomorphic species showedno detectable preference for male eye stalk length. Female matingpreferences of bodi sexually dimorphic species exhibited significantrepeatability, as expected if genetic variation underlies thepreference. In addition, female C whitei and C. dalmanni exhibitedshorter copulations, mated more frequently, and rejected fewermating attempts than female C quinqueguttata. Thus, opportunitiesfor sperm competition have increased with acquisition of femalepreferences. We conclude that female sensory bias for maleswith long eye span did not exist in a common ancestor to thesespecies. Instead, female preference and remating propensityeither coevolved with eye span dimorphism or evolved after maleeye stalks elongated.