Longer Flagella Research Articles

Note on <i>Lucanus</i> Scopoli 1763 species from Southeast Asia with the description of a new species (Coleoptera: Lucanidae)

Lucanus collardi n.sp. from Vietnam and Laos is described. It belongs to the large L. fortunei Saunders 1854 species group and is closely related to L. adelmae Zilioli 2003. Lucanus collardi n.sp. can be easily distinguished at a glance from L. adelmae through the longer and differently denticulated mandibles, the pronounced posterolateral corners of the cephalic lobes, and the aedeagus, with longer flagellum, less widened apex and feebly curved parameres. The female of Lucanus satoi Nagai & Tsukamoto 2003 is also described for the first time, and the genitalia of that species are illustrated.

Flagellum tapering and midpiece volume in songbird spermatozoa.

In contrast to numerous studies on spermatozoa length, relatively little work focuses on the width of spermatozoa, and particularly the width of the midpiece and flagellum. In flagellated spermatozoa, the flagellum provides forward thrust while energy may be provided via mitochondria in the midpiece and/or through glycolysis along the flagellum itself. Longer flagella may be able to provide greater thrust but may also require stronger structural features and more or larger mitochondria to supply sufficient energy. Here, we use scanning electron microscopy to investigate the ultrastructure of spermatozoa from 55 passerine species in 26 taxonomic families in the Passerides infraorder. Our data confirm the qualitative observation that the flagellum tapers along its length, and we show that longer flagella are wider at the neck. This pattern is similar to mammals, and likely reflects the need for longer cells to be stronger against shearing forces. We further estimate the volume of the mitochondrial helix and show that it correlates well with midpiece length, supporting the use of midpiece length as a proxy for mitochondrial volume, at least in between-species studies where midpiece length is highly variable. These results provide important context for understanding the evolutionary correlations among different sperm cell components and dimensions.

Sensilla on antenna and maxillary palp of Neoceratitis asiatica (Diptera: Tephritidae)

Neoceratitis asiatica (Diptera: Tephritidae) is a disastrous pest for wolfberry production in China. In our preliminary field trapping experiment, both female and male N. asiatica adults were captured by male-produced sex attractant. To provide a solid background for studying mechanism of olfaction, the sensilla of antenna and maxillary palp of N. asiatica adults were studied by means of scanning electron microscopy. Both sexes have 3 antennal segments, including scape, pedicel, and flagellum, while arista is arisen from the proximal dorsal ridge of the flagellum. Two types of sensilla were found on the scape and pedicel, sensilla microtrichia (AnMi) and sensilla chaetica (AnCh). There are five types of sensilla on the flagellum, sensilla basiconica (AnB), clavate sensilla (AnCl), sensilla trichoidea (AnTr), sensilla coeloconica (AnCo), and AnMi. Three types of sensilla were observed on maxillary palp, sensilla basiconica (MpB), sensilla microtrichia (MpMi), and sensilla chaetica (MpCh). AnMi and MpMi are the most abundant sensilla type on antenna and maxillary palp, respectively. With the exception of having longer flagellum in females, the dimension of antennal segments, type and number of sensilla, density of pores on the shaft of AnCl, AnCh, AnB and MpB, and at the base area of AnCh and MpCh didn’t show differences between sexes. This lack of inter-sexual differences may be related to chemoreception of male-emitted sex pheromone and of host plant volatiles by both female and male adults.

Variation in sperm morphology and performance in tree sparrow (Passer montanus) under long-term environmental heavy metal pollution.

Sperm morphology and performance traits are key determinants of male fertilization success, particularly when females copulate with multiple males. Such sperm traits have been reported to be influenced by environmental pollutants in various animals; however, such studies remain rare in free-living birds exposed to heavy metal pollution. In the present study, we selected tree sparrow (Passer montanus) as the study object to explore the effect of long-term environmental heavy metal pollution on sperm morphology (assessed mainly by using the dimensions of different sperm components and the sperm abnormality rates) and sperm performance (indicated by sperm velocity), and to elucidate potential relationships between variations in sperm morphology and performance. Sperm ATP concentration was also assessed considering sperm morphology and performance could be linked via energy availability. According to our results, tree sparrows from heavy metal polluted area (1) accumulated cadmium at a higher level in their testes; (2) produced longer sperm with lower abnormality rates, in addition to sperm with longer flagella and smaller head/flagellum ratios; (3) their sperm swam faster compared to those from the relatively unpolluted area, while no differences were observed in sperm ATP concentrations. We also found that the levels of lead and cadmium in testes affected the sperm nucleus length, and the level of copper in testes was negatively related to the proportions of abnormal sperm. Furthermore, the present study showed that sperm velocity was negatively correlated with sperm head lengths, head/flagellum ratios and ATP concentrations. Our study results reveal that sperm morphology and performance in tree sparrows show positive variations to maximize male fertility ability under long-term environmental heavy metal pollution, where males increase sperm flagellum lengths to decrease head/flagellum ratios, as opposed to varying sperm energy production, to achieve higher sperm velocity.

The motility-based swim-up technique separates bull sperm based on differences in metabolic rates and tail length.

Swim-up is a sperm purification method that is being used daily in andrology labs around the world as a simple step for in vitro sperm selection. This method accumulates the most motile sperm in the upper fraction and leaves sperm with low or no motility in the lower fraction. However, the underlying reasons are not fully understood. In this article, we compare metabolic rate, motility and sperm tail length of bovine sperm cells of the upper and lower fraction. The metabolic assay platform reveals oxygen consumption rates and extracellular acidification rates simultaneously and thereby delivers the metabolic rates in real time. Our study confirms that the upper fraction of bull sperm has not only improved motility compared to the cells in the lower fraction but also shows higher metabolic rates and longer flagella. This pattern was consistent across media of two different levels of viscosity. We conclude that the motility-based separation of the swim-up technique is also reflected in underlying metabolic differences. Metabolic assays could serve as additional or alternative, label-free method to evaluate sperm quality.

Sexual selection and the evolution of sperm morphology in sharks.

Post-copulatory sexual selection, and sperm competition in particular, is a powerful selective force shaping the evolution of sperm morphology. Although mounting evidence suggests that post-copulatory sexual selection influences the evolution of sperm morphology among species, recent evidence also suggests that sperm competition influences variation in sperm morphology at the intraspecific level. However, contradictory empirical results and limited taxonomic scope have led to difficulty in assessing the generality of sperm morphological responses to variation in the strength of sperm competition. Here, we use phylogenetically controlled analyses to explore the effects of sperm competition on sperm morphology and variance in sharks, a basal vertebrate group characterized by wide variation in rates of multiple mating by females, and consequently sperm competition risk. Our analyses reveal that shark species experiencing greater levels of sperm competition produce sperm with longer flagella and that sperm flagellum length is less variable in species under higher sperm competition risk. In contrast, neither the length of the sperm head and midpiece nor variation in sperm head and midpiece length was associated with sperm competition risk. Our findings demonstrate that selection influences both the inter- and intraspecific variation in sperm morphology and suggest that the flagellum is an important target of sexual selection in sharks. These findings provide important insight into patterns of selection on the ejaculate in a basal vertebrate lineage.

Ophirina amphinema n. gen., n. sp., a New Deeply Branching Discobid with Phylogenetic Affinity to Jakobids

We report a novel nanoflagellate, Ophirina amphinema n. gen. n. sp., isolated from a lagoon of the Solomon Islands. The flagellate displays ‘typical excavate’ morphological characteristics, such as the presence of a ventral feeding groove with vanes on the posterior flagellum. The cell is ca. 4 µm in length, bears two flagella, and has a single mitochondrion with flat to discoid cristae. The flagellate exists in two morphotypes: a suspension-feeder, which bears flagella that are about the length of the cell, and a swimmer, which has longer flagella. In a tree based on the analysis of 156 proteins, Ophirina is sister to jakobids, with moderate bootstrap support. Ophirina has some ultrastructural (e.g. B-fibre associated with the posterior basal body) and mtDNA (e.g. rpoA–D) features in common with jakobids. Yet, other morphological features, including the crista morphology and presence of two flagellar vanes, rather connect Ophirina to non-jakobid or non-discobid excavates. Ophirina amphinema has some unique features, such as an unusual segmented core structure within the basal bodies and a rightward-oriented dorsal fan. Thus, Ophirina represents a new deeply-branching member of Discoba, and its mosaic morphological characteristics may illuminate aspects of the ancestral eukaryotic cellular body plan.

Correction to 'Shape, form, function and Leishmania pathogenicity: from textbook descriptions to biological understanding'.

Open AccessMoreSectionsView PDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmail Cite this article Sunter Jack and Gull Keith 2018Correction to ‘Shape, form, function and Leishmania pathogenicity: from textbook descriptions to biological understanding’Open Biol.8180134180134http://doi.org/10.1098/rsob.180134SectionOpen AccessCorrectionCorrection to ‘Shape, form, function and Leishmania pathogenicity: from textbook descriptions to biological understanding’ Jack Sunter Jack Sunter http://orcid.org/0000-0002-2836-9622 Google Scholar Find this author on PubMed Search for more papers by this author and Keith Gull Keith Gull Google Scholar Find this author on PubMed Search for more papers by this author Jack Sunter Jack Sunter http://orcid.org/0000-0002-2836-9622 Google Scholar Find this author on PubMed Search for more papers by this author and Keith Gull Keith Gull Google Scholar Find this author on PubMed Search for more papers by this author Published:29 August 2018https://doi.org/10.1098/rsob.180134This article corrects the followingReview ArticleShape, form, function and Leishmania pathogenicity: from textbook descriptions to biological understandinghttps://doi.org/10.1098/rsob.170165 Jack Sunter and Keith Gull volume 7issue 9Open Biology13 September 2017Open Biol.7, 170165. (Published online 13 September 2017). (doi:10.1098/rsob.170165)A correction is required to table 2 of our above review. All the authors gave their consent to this correction.The correct version of table 2 is as follows:Table 2.Summary of morphological and/or motility mutants in Leishmania. Collapse proteingeneIDphenotypeconserved across Leishmania species on TriTrypDBv33development in sand fliespathogenicity in macrophagespathogenicity in animalsreferencePFR2LmjF.16.1425/1427/1430PFR-2 knockout cells had an altered flagellar beat with a reduced swimming velocityyesnot donenot donenot done[66]PFR1LmjF.29.1750/1760/1770Both PFR-1 knockout cells and PFR1/2 double knockout cells had an altered flagellar beat with a reduced swimming velocityyesnot donenot donenot done[67]ARL-3ALdBPK_290950.1Cells overexpressing a constitutively ‘active’ form of ARL-3A were immotile with short flagella and flagellum length was inversely proportional to mutant protein expressionyesunable to develop in sand fliesno change in macrophage infectivitynot done[68,18]MKKLmxM.08_29.2320MKK knockout cells had motile flagella, which was dramatically shorter and lacked a paraflagellar rod and also had shorter cell bodiesyesnot donenot donelong delay in lesion development[69]MPK9LmxM.19.0180MPK9 knockout cells had longer flagella, whereas overexpression led to a subpopulation with short/no flagellayesnot donenot donelesions developed slightly slower with knockout cells[70]DHC2.2LmxM.27.1750DHC2.2 knockout cells were immotile and had a rounded cell body. The flagellum that did not extend beyond the cell body and lacked a paraflagellar rod and other axonemal structuresyesnot donenot donenot done[71]MPK3LmxM.10.0490MPK3 knockout cells had shorter flagella with stumpy cell bodiesyesnot donenot doneno change in lesion development[72]Kin13-2LmjF.13.0130Kin13-2 knockout cells had longer flagella, whereas overexpression led to shorter flagella.yesnot donenot donenot done[73]ADF/cofilinLdBPK_290520.1ADF/cofilin (actin-depolymerizing factor) knockout cells were immotile with shorter flagella and a disrupted beat pattern. The cells were also shorter and wideryesnot donenot donenot done[74]KataninLmjF13.0960Cells overexpressing katanin-like homologue had shorter flagellayesnot donenot donenot done[75]SMP1LmjF.20.1310Loss of SMP1 caused a reduction in flagellum length and defects in motilityyesnot donenot donenot done[76]DC2LdBPK_323050.1DC2 knockout cells had shorter flagella with a disrupted ultrastructure and reduced motility. Moreover, the cell bodies were shorter with a more amastigote appearanceyesnot doneslight increase in macrophage infectivitynot done[77]Inhibitor of Serine Peptidase 1 (ISP1)LmjF.15.0300ISP1/2/3 triple knockout cells had longer flagella and were less motile than ISP2/3 double knockout cells. Moreover, the triple knockout had a greater number of cells with haptomonad, nectomonad and leptomonad morphologies. There was also a change in the shape of the anterior end of these cellsyesnot donereduced survival in macrophagesnot done[78] Previous Article VIEW FULL TEXT DOWNLOAD PDF FiguresRelatedReferencesDetailsRelated articlesShape, form, function and Leishmania pathogenicity: from textbook descriptions to biological understanding13 September 2017Open Biology This IssueAugust 2018Volume 8Issue 8 Article InformationDOI:https://doi.org/10.1098/rsob.180134PubMed:30158322Published by:Royal SocietyOnline ISSN:2046-2441History: Published online29/08/2018 License:© 2018 The Authors.Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. Citations and impact Subjectscellular biologymicrobiology molecular biology

Lucanus gradivus n. sp. from Vietnam, with new records of L. fujitai Katsura and Giang from Vietnam and Laos (Coleoptera, Lucanidae)

Lucanus gradivus n.sp. from Vietnam is described. It belongs to the large of L. fortunei Saunders, 1854 species group and is closely related to L. fujitai Katsura and Giang 2002. Lucanus gradivus differs mainly through the stronger and differently denticulated mandibles, larger and more pronounced posterolateral corners of the cephalic lobes, and the aedeagus, with longer flagellum, shorter and thinner median lobe, and longer apically curved parameres.

Ampithoe qeshmensis sp. nov. (Amphipoda: Ampithoidae), a new herbivorous amphipod from the Persian Gulf

Herbivorous amphipods of the family Ampithoidae have an important role in marine ecosystems. Ampithoe qeshmensis sp. nov. is a new member of Ampithoidae from the Qeshm Island, Persian Gulf. The new species resembles A. kava, A. katae and A. cookana based on the second male gnathopod. Ampithoe qeshmensis sp. nov. is characterized by round and reduced distoventral spur on uropod 1 in male, mandibular palp article 3 longer than second one, robust seta on palm of second male gnathopod, and longer flagellum than peduncular article 5 on the second antenna.

Comparison of spermatozoa parameters, fine structures, and energy‐related factors among tetraploid, hyper‐tetraploid, and hyper‐triploid loaches (Misgurnus anguillicaudatus)

To evaluate the influence of ploidy elevation and aneuploidy on spermatozoa in the loach Misgurnus anguillicaudatus, we investigated some parameters (motility, concentration, and viability), fine structures (gross morphology, head size, and flagellum length), and energy-related biochemical factors (volume of mitochondrial mass per cell and ATP content) in diploid, hyper-diploid, and hexaploid-range spermatozoa produced in natural tetraploid, hyper-tetraploid, and hyper-triploid male loaches, respectively. Diploid spermatozoa exhibited vigorous movement and sufficient duration of motility similar to those in haploid spermatozoa. They had longer flagella, higher numbers and larger volume of mitochondria, and higher ATP content than haploid spermatozoa of wild-type diploids. No differences were observed in parameters and morphological characteristics between diploid and hyper-diploid spermatozoa. In contrast, the hexaploid-range spermatozoa of hyper-triploid males exhibited poor progressive motility in spite of a higher ATP content of spermatozoa. Spermatozoa with no flagella (36.0%) or multiple flagella (18.6%) were also observed in hyper-triploids. Ratios of head to flagellum length in hexaploid-range spermatozoa were significantly different from those of haploid spermatozoa. In addition to the normal 9+2 microtubule structure of the flagellum, an abnormal 9+1 microtubule structure was also observed in the spermatozoa of hyper-triploids.

RELATIONSHIPS BETWEEN SPERM LENGTH AND SPEED DIFFER AMONG THREE INTERNALLY AND THREE EXTERNALLY FERTILIZING SPECIES

It is often assumed that longer sperm, by virtue of their increased swimming speed, have a fertilization advantage over shorter sperm when in competition to fertilize eggs. However, there is surprisingly little evidence for a positive correlation between sperm length and speed. Here we use an approach that accounts for within-male variation in sperm traits to examine the relationships between sperm length and sperm speed across a broad range of species, including three internally fertilizing species and three externally fertilizing species. Our results reveal that correlations between sperm size and speed are indeed present and possibly more common than currently thought. However, the direction of the correlations between sperm length and speed, which are more prevalent within a male's ejaculate than among males, were influenced by fertilization mode in contrasting and unexpected ways. Broadly, the patterns revealed that in externally fertilizing species sperm with longer flagellum and shorter heads relative to their flagellum swam faster, whereas in internally fertilizing species sperm with shorter flagellum and longer heads relative to their flagellum swam faster. We discuss these results in light of sperm competition theory and contrast the intraspecific patterns observed in this study with macroevolutionary patterns of sperm evolution reported elsewhere.

Motility, morphology, mitochondria and ATP content of diploid spermatozoa from sex-reversed clonal diploid and neo-tetraploid loach,Misgurnus anguillicaudatus

Summary Diploid spermatozoa were obtained from sex-reversed clonal diploid males and neo-tetraploid which derived from normal diploid × natural tetraploid cross followed by the 2nd polar body release inhibition. The spermatozoa from sex-reversed clonal diploid males exhibited a significant reduction in motility when compared with those from normal diploid and neo-tetraploid males. Electron microscopy revealed that diploid spermatozoa from sex-reversed clonal diploid and neo-tetraploid males exhibited normal shape similar to haploid spermatozoa from normal diploid males, except for larger sperm-head size and longer flagellum. Considering flow-cytometric results, volume of mitochondrial mass per spermatozoon was also increased in proportion to the elevation of ploidy status from haploid to diploid sperm. Diploid spermatozoa from neo-tetraploid increased the number of mitochondria and the ATP content, but those from sex-reversed clonal diploid males did not show such results.

Alternative mating strategies may favour the persistence of a genetically based colour polymorphism in a pentamorphic fish

Males of the pentamorphic fish, Poecilia parae , show a striking colour polymorphism that ranges from drab coloration resembling females to brilliant black and red stripes. We tested the hypothesis that the observed polymorphism may persist because each morph uses a unique but equally successful mating strategy. We quantified the mating behaviour, testes investment and sperm morphometrics of each morph. We found that the smallest morph (immaculata), which resembles drab females, used a ‘sneaker’ tactic (i.e. forgoing courtship and mostly ‘stealing’ copulations) as a mating strategy. Immaculata males also had larger testes, and produced larger ejaculates and sperm with longer flagella, which should provide advantages during sperm competition. The largest morph (parae) and the coloured blue, red and yellow morphs used a combination of courtship and sneaker tactics. However, they achieved greater copulation success as a result of courtships. The testes investment of parae and yellow morphs were similar but larger than those of the blue and red males. Our results suggest that male morphs of the pentamorphic Poecilia parae use unique mating strategies that exploit different aspects of pre- and postcopulatory sexual selection, which, in turn, may help maintain their relatively stable frequencies in the wild.

Analysis of Pseudomonas fluorescens F113 genes implicated in flagellar filament synthesis and their role in competitive root colonization

The ability of plant-associated micro-organisms to colonize and compete in the rhizosphere is specially relevant for the biotechnological application of micro-organisms as inoculants. Pseudomonads are one of the best root colonizers and they are widely used in plant-pathogen biocontrol and in soil bioremediation. This study analyses the motility mechanism of the well-known biocontrol strain Pseudomonas fluorescens F113. A 6.5 kb region involved in the flagellar filament synthesis, containing the fliC, flaG, fliD, fliS, fliT and fleQ genes and part of the fleS gene, was sequenced and mutants in this region were made. Several non-motile mutants affected in the fliC, fliS and fleQ genes, and a fliT mutant with reduced motility properties, were obtained. These mutants were completely displaced from the root tip when competing with the wild-type F113 strain, indicating that the wild-type motility properties are necessary for competitive root colonization. A mutant affected in the flaG gene had longer flagella, but the same motility and colonization properties as the wild-type. However, in rich medium or in the absence of iron limitation, it showed a higher motility, suggesting the possibility of improving competitive root colonization by manipulating the motility processes.

Relationships between sperm morphometry and sperm motility in the Atlantic salmon

Relationships between spermatozoal design and swimming behaviour were investigated using the significant natural variance in sperm traits in Atlantic salmon Salmo salar. In vitro motility and fertilization experiments were conducted with 86 Atlantic salmon to measure sperm form and function under natural fertilization conditions. Spermatozoal traits of Atlantic salmon showed narrow variance within individuals but differed extensively between samples: mean sperm length varied from 32·3 to 39·5 μm, mean velocity ranged from 18 to 127 μm s−1, and ejaculate longevity varied from 18 to 78 s. In addition to variation in sperm morphometry between fish, a negative relationship was also found between sperm head length and flagellum length. This natural variation in sperm form and function between males is counter‐intuitive since measures are from a single Atlantic salmon population where all males are adapted to a common fertilization environment. No evidence was found that longer sperm, or sperm with longer flagella, achieved faster swimming velocities. Also no evidence was found for a trade‐off between mean sperm velocity and ejaculate longevity. There were significant negative associations, however, between sperm total and flagellum length and ejaculate longevity, so that males with longer sperm had shorter‐lived gametes. This finding has previously been reported in a study across fish species, supporting the theory that increased hydrostatic forces generated by longer flagella may trade against sperm cell longevity.

CHARACTERIZATION AND PHYLOGENETIC POSITION OF THE ENIGMATIC GOLDEN ALGA PHAEOTHAMNION CONFERVICOLA: ULTRASTRUCTURE, PIGMENT COMPOSITION AND PARTIAL SSU rDNA SEQUENCE

The morphology, ultrastructure, photosynthetic pigments, and nuclear‐encoded small subunit ribosomal DNA (SSU rDNA) were examined for Phaeothamnion confervicola Lagerheim strain SAG119.79. The morphology of the vegetative filaments, as viewed under light microscopy, was indistinguishable from the isotype. Light microscopy, including epifluorescence microscopy, also revealed the presence of one to three chloroplasts in both vegetative cells and zoospores. Vegetative filaments occasionally transformed to a palmelloid stage in old cultures. An eyespot was not visible in zoospores when examined with light microscopy, but small droplets, similar to eyespot droplets, were apparent beneath the shorter flagellum when cells were viewed with electron microscopy. Zoospores had two flagella that were laterally inserted in the cell approximately one‐third of the cell length from the apex. The longer flagellum was directed anteriorly and the shorter flagellum was directed posteriorly. Electron microscopy revealed the presence of tubular tripartite flagellar hairs on the longer flagellum, but no lateral filaments were found on the tripartite hairs. The general organization of the flagellar root system was similar to that of zoospores belonging to the Xanthophyceae and Phaeophyceae. However, the transitional region of the flagella contained a transitional helix with four to six gyres. Microtubular root R1 consisted of six microtubules at its proximal end and one microtubule at its distal end. Roots R2 and R4 consisted of one microtubule each and root R3 consisted of two microtubules. No rhizoplast was found. Thin‐layer chromatography revealed the presence of fucoxanthin, diadinoxanthin, neoxanthin, and heteroxanthin as well as chlorophylls a, c1 and c2. High‐performance liquid chromatography revealed the presence of fucoxanthin, diadinoxanthin, diatoxanthin, heteroxanthin, and β,β‐carotene as well as chlorophylls a and c. The complete sequence of the SSU rDNA could not be obtained, but a partial sequence (1201 bases) was determined. Parsimony and neighbor‐joining distance analyses of SSU rDNA from Phaeothamnion and 36 other chromophyte algae (with two Öomycete fungi as the outgroup) indicated that Phaeothamnion was a weakly supported (bootstrap = <50%, 52%) sister taxon to the Xanthophyceae representatives and that this combined clade was in turn a weakly supported (bootstrap = <50%, 67%) sister to the Phaeophyceae. Based upon ultrastructural observations, pigment analysis, and SSU rDNA phylogenetic analysis, Phaeothamnion is not a member of the Chrysophyceae and should be classified as incertae sedis with affinities to the Xanthophyceae and Phaeophyceae.

Ultrastructural biology of Leishmania (Viannia) panamensis (=Leishmania braziliensis panamensis) in Lutzomyia gomezi (Diptera: Psychodidae): a natural host-parasite association.

The development of Leishmania (Viannia) panamensis in a natural sand fly host, Lutzomyia gomezi, was studied by light and transmission electron microscopy. New aspects of peripylarian parasite behavior and morphology in the sand fly gut, early bloodmeal stages, and ultrastructural development in the anterior gut were documented. Eight distinct morphological forms were observed in the life cycle of the parasite within the insect. In the bloodmeal, amastigotes (1) transformed into stumpy promastigotes (2) which rapidly multiplied, resulting in spatulate-shaped nectomonad promastigotes (3) and elongate nectomonad promastigotes (4). These latter forms migrated primarily into the hindgut, where both were observed attached (=haptomonad phase) to the cuticular intima by hemidesmosomes within extremely shortened flagella. Spatulate haptomonad promastigotes predominated, colonizing the entire length of the hindgut, with the greatest density at 2 disjunct sites: the pylorus/ileum and the anterior rectum/rectal sac. Paramastigotes and dividing flagellates were rare. Some parasites migrated directly to the cardia/stomodeal valve region without a hindgut phase; however, major movement anteriorly was from the hindgut beginning at 6 days postinfection. In the cardia lumen, dividing short Type A promastigotes (5) predominated, intermixed with short Type B promastigotes with longer flagella (6). Paramastigotes (7) were free-swimming in the lumen as well as attached to the stomodeal valve. The primary colonizers of the valve were pear-shaped haptomonad promastigotes (8), with flagella of variable lengths and multi-segmented hemidesmosomal attachment points to the intima. Promastigotes and paramastigotes colonized the esophagus-pharynx region and attached to the foregut lining by flagellar hemidesmosomes. Both forms may represent infective stages of L. (V.) panamensis; however, no parasites were detected in the cibarium or proboscis. L. (V.) panamensis appeared well-adapted to the gut of Lu. gomezi, multiplying extensively at 2 sites, changing morphological form, and adhering to host surfaces by variously modified flagellar hemidesmosomes.

Studies in the fine structure and taxonomy of flagellates in the genusPavlova. II. A freshwater representative,Pavlova granifera(Mack) comb. Nov.

The fine structure of the palmelloid and swimming cells of Chrysocapsella granifera (Mack) Bourrelly is described. Many features, for example the superficial deposit on the longer flagellum, the presence of a reduced haptonema, the pit penetrating the cell close to the appendages and the strongly refringent inclusion bodies, are strikingly similar to those of members of the genus Pavlova Butcher (Haptophyceae). The taxonomic position of C. granifera in relation to this and other genera is discussed. The organism is transferred to the genus Pavlova and a revised description of Pavlova granifera (Mack) comb. nov. given.