Studies of the Phoront of Hyalophysa chattoni (Ciliophora,Apostomatida) Encysted on Grass Shrimp1

ABSTRACT. The apostomatous ciliate Hyalophysa chattoni, an ectosymbiont of the grass shrimp Palaemonetes pugio, encysts and dedifferentiates within 48 h from the migratory tomite to a phoretic stage devoid of complex ciliary fields. The presettlement crawling and pivoting of the tomite may play a role in its initial attachment to the shrimp. Metamorphosis of exuviotrophic apostomes has been previously observed to take place immediately prior to host ecdysis. The study has found that Hyalophysa's metamorphosis to the feeding stage on grass shrimp is initiated by a cue from the premolt host and begins during earlier stages of the molt cycle (D₀ and D₁). Due to the long premolt stage of the host's diecdysic molt cycle, metamorphosis is initiated well before ecdysis (over six days). Hyalophysa was able to encyst and metamorphose within 41/4 h when exposed to shrimp in a late premolt stage, indicating that the control of apostome metamorphosis is solely host-dependent.     

The Fine Structure of Conidophrys pitelkae Bradbury Related to its Life Cycle and Taxonomic Position in the Apostomatida1

Electron microscopy of the tomite of Conidophrys pitelkae confirms that Jankowski was correct in including the pilisuctorians in the Apostomatida. Like other apostome tomites, the tomite of Conidophrys possesses a rosette opening to the exterior, kinetodesmata made up of stacks of individual kinetodesmal fibrils, and canaliculi that are surrounded by dense inclusion bodies and open on the ventral surface. The fine structure of the trophont of Conidophrys, however, is quite unlike that of other apostome trophonts. The elaborate infraciliature of the tomite disappears immediately after it settles and reappears de novo on the trophont just before tomitogenesis. The cyst wall, which completely encloses the trophont and grows with it, attaches the ciliate to a seta on its, host, the shrimp Crangon crangon. The setae on which tomites settle vary greatly in size and shape, but each appears to have at its tip some digitiform cuticular projections that surmount a pore, which opens into the lumen of the seta. The trophont's only direct connection to its host is at the cytostome, a unique structure formed of delicate tubules that pass through the pore into the lumen of the seta. Ingestion is by micropinocytosis, and there are no visible food reserves.     

The Life Cycle and Morphology of the Apostomatous Ciliate,Hyalophysa chattoni n. g., n. sp.*

SYNOPSIS. A new apostome ciliate was discovered in collections at Friday Harbor, Washington and the San Francisco area. All stages of the life cycle were studied in both living and stained condition. Dormant encysted stages (phoronts) occur on the gills of Pagurus hirsutiusculus. Excystation occurs in synchrony with the molting of the host yielding the trophic stage (trophont), which feeds on the exuvial fluids trapped in the crab's cast-off exoskeleton. The trophont becomes greatly enlarged as a result of feeding, and the cytoplasm and organelles become compressed into a thin cortical layer. Each fully grown trophont encysts (becoming a tomont) as a prelude to repeated binary fission, which results in the release of actively motile offspring (tomites). These disperse and promptly resume the encysted phoront stage on the host's gills. The Chatton-Lwoff silver impregnation method revealed that all stages of the life cycle have nine somatic kineties. In the trophont stage they are accompanied by an anterior ventral field of scattered clumps of kinetosomes. During conjugation the partners attach by their ventral surfaces between kineties 1 and 9 and at the left of the ventral field. The tomite stage was stained with Protargol. In addition to the characteristic features of the foettingeriid tomite also revealed by the Chatton-Lwoff method, Protargol revealed the following heretofore undescribed morphological features: a short row of kinetosomes immediately anterior to the ogival field; a line paralleling the left margin of the field; the continuity of kinety 8 with falciform field 8; the entrance of kinety 9 into the mouth and its ending against the rosette (an enigmatic organelle characteristic of Foettingeriinae). Feulgen stains showed that the chromatin in the macronucleus is dispersed in aggregates whose size and number vary with the stage of the life cycle. The major period of chromatin synthesis appears to be during the early tomont stage, when Feulgen-positive material increases visibly in amount and intensity of staining. This apostome ciliate was characterized as a new genus on the basis of the infraciliature of the trophont stage, its conjugation with ventral surfaces appressed, and its life cycle. It is named Hyalophysa (hyalo = glassy, physa = bubble) chattoni.     

Terebrospira chattoni sp. n., a Parasite of the Endocuticle of the Shrimp Palaemonetes pugio Holthuis*

SYNOPSIS. Terebrospira chattoni sp. n. may be a species in transition between ectosymbiosis and endosymbiosis. It penetrates the epicuticle of Palaemonetes pugio and feeds on the endocuticle by dissolving galleries through it and absorbing the products of dissolution. Although similar in some respects to species of the endosymbiotic apostome genus Synophrya, T. chattoni is clearly related to ectosymbiotic apostomes that feed on exuvial fluid. However, instead of stimulating the metamorphosis of a phoront to a trophont, the host's ecdysis stimulates T. chattoni to metamorphose from a dedifferentiated trophont with 13 meridional kineties to a protomont, a predivision stage with 10 spiralled kineties. The protomont encysts and dedifferentiates to the division stage, an orthotomont with 13 kineties, either on the new exoskeleton before ecdysis, within a chamber in the endocuticle of the old exoskeleton, or on a substrate away from the host and the molt. The site of division determines the product of the division. On the new exoskeleton, the tomites in the reproductive cyst secrete walls around themselves thereby forming the lenticular, compartmented cysts characteristic of Terebrospira. Each daughter tunnels out of its compartment into the endocuticle. Although its infraciliature remains undifferentiated like that of the orthotomont, the ciliate in the gallery is the trophont, the only feeding stage in the life cycle. Daughters originating from the division of the orthotomont in a chamber in the endocuticle swim out of the exoskeleton at ecdysis. encyst on the substrate, and presumably form tomites. When the protomont itself leaves the molt, it encysts on the substrate and divides to form daughter cells with a rosette and the pattern of ciliature of the conventional tomite of other apostome genera. Tomites carry the infection to new hosts while compartmented cysts insure that the original host retains the infection. Terebrospira chattoni is always astomatous, although a dedifferentiated oral ciliature appears in the orthotomont and persists in the trophont. Terebrospira chattoni sp. n. is separated from T. lenticularis Debaisieux the other species in the genus because the latter species may divide outside a cyst and because T. chattoni has an extra reproductive stage in its life cycle.     

Lynnia grapsolytica n. gen,n. sp. (Ciliophora: Apostomatida: Colliniidae), a Deadly Blood Parasite of Crabs with a Novel Pseudocytopharynx

We describe a new genus and species of blood-dwelling apostome ciliate, Lynnia grapsolytica n. gen., n. sp. (Apostomatida: Colliniidae). A distinct kinety “hook” pattern on the tomite’s posterior ventral face, coupled with its marine habitat and use of a decapod host, readily distinguishes this ciliate from all known colliniids. We detected the parasite in ~12% of Pachygrapsus crassipes (Brachyura: Grapsidae) crabs in a California estuary and confirmed its presence at a Baja California rocky intertidal site. As existing methods failed to adequately stain this ciliate, we developed a new miniaturized silver carbonate impregnation staining method that produced excellent somatic and nuclear stains in all five observed cell types. A possibly unique trait is the active invagination of the tropho-tomont’s anterior to form a temporary “pseudocytopharynx,” likely used for feeding. Histological examination revealed that the ciliate invaded and damaged skeletal muscle, the heart, connective tissues, and gonads. Survivorship analysis indicated that infected crabs experienced 2.6 times greater daily mortality than uninfected crabs. Laboratory and field experimental infection attempts failed, suggesting a complex life cycle with outside-host development. Phylogenetic analysis at the 18S and COI loci confirmed the ciliate's placement in the Colliniidae. We emend the diagnosis of Family Colliniidae.     

Exuviotrophic apostome ciliates from crustaceans of St. Andrew Bay, Florida, and a description of Gymnodinioides kozloffi n. sp

Gymnodinioides kozloffi n. sp. is described from the eelgrass broken-back shrimp Hippolyte zostericola. The species is distinct from others in the apostome genus Gymnodinioides in that the trophont ciliature has a small group of kinetosomes located to the right of Kinety 9a, and Kinety 1 and 2 are divided. Other apostome morphologies are described from many decapod crustaceans from St. Andrew Bay, Florida, including Gymnodinioides inkystans, Hyalophysa chattoni, and variants of both H. chattoni and G. kozloffi. All of these apostome ciliates are exuviotrophic, found feeding on exuvial fluid within the exoskeleton of the host after ecdysis. The hosts surveyed for this study are the following: Callinectes sapidus, Eurypanopeus depressus, Hippolyte zostericola, Farfantepenaeus spp., Palaemonetes intermedius, Palaemon floridanus, Portunus spp., Tozeuma carolinense, and Sicyonia laevigata, which revealed a number of new host-apostome records.     

The Fine Structure of Secretion in Hyalophysa chattoni: Formation of the Attachment Peduncle and the Chitinous Phoretic Cyst Wall

ABSTRACT. The settling tomite stage of the apostome Hyalophysa chattoni secretes a phoretic cyst wall composed of chitin, mucopolysaccharides, and protein. Within 1 1/2 h after settling, an electron-dense proteinaceous cyst layer (the outer layer) is formed from secretions originating at the base of the kineties and from the thick pellicular layer between the kineties. The inner cyst layer, composed primarily of chitin (acidic and neutral polysaccharides are also present), is secreted across the entire cell surface. Cyst wall formation is completed within 6 h. The fine structure of endocyst secretion resembles stages in the secretion of chitin by fungi, yeasts, and arthropods. A proteinaceous attachment peduncle is secreted to anchor the cell to a shrimp host and is formed by the release of electron-dense secretory bodies from the cell's ventral surface.     

The Fine Structure of the Internal Spiral of Kinetosomes in Foettingeria's Tomite,a Unique Storage Depot for Kinetosomes1

ABSTRACT. The fine structure of the tomite of Foettingeria actiniarum (Claparède) was examined and compared with that of other apostome tomites. This stage in the life cycle has a unique configuration of kineties that form a spiral through the cytoplasm in the interior of the body. The structure and behavior of this internal spiral were evaluated as a mechanism for the storage of kinetosomes, an adaptation to the ciliate's two-host life cycle. The spiral is composed of nine ribbons of laterally compressed kinetosomes that are in contact with a thin electron-dense fibril. Paralleling the kineties of the spiral are conspicuous, swollen lamellae of the rough endoplasmic reticulum; these lamellae contain moderately electron-dense material. The spiral is associated with the large contractile vacuole and winds about the macronucleus. The tomite of Foettingeria possesses a single, robust, caudal cilium located in a pit, along with the nozzle-like pore of the contractile vacuole. The walls of the pit contain several trichocysts arranged radially about the caudal cilium and aimed into the pit.     

The fine structure of secretion in Hyalophysa chattoni: formation of the attachment peduncle and the chitinous phoretic cyst wall.

The settling tomite stage of the apostome Hyalophysa chattoni secretes a phoretic cyst wall composed of chitin, mucopolysaccharides, and protein. Within 1 1/2 h after settling, an electron-dense proteinaceous cyst layer (the outer layer) is formed from secretions originating at the base of the kineties and from the thick pellicular layer between the kineties. The inner cyst layer, composed primarily of chitin (acidic and neutral polysaccharides are also present), is secreted across the entire cell surface. Cyst wall formation is completed within 6 h. The fine structure of endocyst secretion resembles stages in the secretion of chitin by fungi, yeasts, and arthropods. A proteinaceous attachment peduncle is secreted to anchor the cell to a shrimp host and is formed by the release of electrondense dense secretory bodies from the cell's ventral surface.     

The Biology of Vampyrophrya pelagica (Chatton & Lwoff, 1930), a Histophagous Apostome Ciliate Associated with Marine Calanoid Copepods

ABSTRACT. The histophagous apostome. l'ampyrophrya pelagica , occurs on calanoid copepods in North Carolina. Its life cycle has two pathways: one when the copepod host is injured; the other when the host is ingested by an invertebrate predator. The ciliate, immediately after encysting on a copepod. metamorphoses to a feeding stage. When its host is injured or ingested by a predator, it excysts enters the wound and ingests the host's cytoplasm. In the single-host life cycle, after feeding, the ciliate encysts within the cadaver; in the two-host life cycle, after feeding it encysts upon a substrate. Encysted cells divide into 2–32 migratory tomites. Freed tomites are motionless in the water column until the water is disturbed, at which time they spring in the direction of any vibration, which many times results from a feeding copepod. Tomites select specific hosts, since not all species of copepods are infested. We hypothesize that the single-host life cycle yields many tomites that heavily infest hosts at random, and passage through the predator (two-host life cycle) results in fewer, but more widely dispersed tomites that are released continuously. The two-host life cycle is facultative for the individual, but may be obligate for the continuation of the species.     

Effect of the venom of the gregarious parasitoid Apanteles glomeratus on its hemocytic encapsulation by the host, Pieris

When eggs from the lateral oviduct of the gregarious parasitoid Apanteles glomeratus were injected with calyx fluid and venom apparatus material into host larvae, Pieris rapae crucivora, most of the eggs were not encapsulated. Apanteles eggs deposited by the parasitoid from which the venom apparatus was removed were usually encapsulated by the host. These results indicate that the parasitoid venom apparatus material is an important factor in suppressing the encapsulation of 1- or 2-day-old eggs in the host. In order to clearly demonstrate that the venom suppresses egg encapsulation but not the encapsulation of other foreign objects, DEAE-Sephadex A-50 ion-exchange particles stained with 0.001% (w/v) Congo Red solution were injected into hosts together with venom apparatus material. The Sephadex particles were encapsulated by host hemocytes. The results suggest that the venom does not inhibit the encapsulation ability of the host.     

Avoidance of intraspecific competition via host modification in a grazing, fruit-eating insect

Insects feeding on plants may induce chemical and physical changes in the host plants. Here, we present evidence of host plant modification following an insect attack that may be associated with a reduction in intraspecific competition for food. We demonstrate that feeding by larvae of the cranberry fruitworm, Acrobasis vaccinii, induces a change in fruit colour (from green to red) of cranberry fruits, Vaccinium oxycoccos, that is associated with a significant increase in the concentration of anthocyanin. Host fruit colour affected larval foraging behaviour and food acceptance: significantly more cranberry fruitworm larvae were attracted to, and accepted, green rather than red fruits. Our experiments suggest that fruit reddening also prevents exploitation by conspecific larvae of other green fruits adjacent to the attacked fruit.     

The fine structure of the hypertrophont of the parasitic apostome Synophrya (Ciliophora,Apostomatida)

The hypertrophont stage of the parasitic apostome ciliate Synophrya was studied by light microscopy and transmission electron microscopy. This invasive stage of the ciliate was found within the gill lamellae and gill raphes of the longspine swimming crab Portunus spinicarpus. The ciliates elicited a melanized host reaction that walled off the parasite from the host. Additionally the ciliate produced a cyst wall of ～0.16-2.0 μm in thickness that further isolated the parasite. A mouth was not observed, as the internal stage of this ciliate takes in material via endocytosis across the entire surface. The outer surface was irregular, with folds, membrane pillows, and vesicles connected to the outer membrane. The hypertrophont had a sparce ciliature, with well developed kinetodesmal fibers connecting the kinetosomes. Within the cytoplasm the cell had numerous vacuoles, lipid droplets, and large plaquettes of material. The massive reticulate macronucleus had globular and elongated chromatin bodies, and was the most distinctive organelle within the cell.     

Artificial feeding of Varroa destructor through a chitosan membrane: a tool for studying the host-microparasite relationship

Rearing pests or parasites of very small size in the absence of their living host is a challenge for behavioural, physiological and pathological studies. For feeding Varroa destructor, an ectoparasitic mite of Apis mellifera, a confinement space with a membrane separating the nutritive solution and the space was designed. The mite measures less than 2 mm and bears a perforating apparatus with a length of 15 μm. The membrane, an essential element of the chamber, has a thickness of 0.1 μm, and is made of chitosan. It closes one face of the individual confinement chamber and allows piercing and the ingestion of the nutritive solution. Factors inducing feeding can be applied on the inner walls or on the membrane. In the particular case of Varroa, the highest percentages of feeding mites are obtained by addition of host haemolymph to the nutritive solution, suggesting the kairomonal role of haemolymph in addition to its nutritional one. The membrane concept can be easily applied to several mites or other micro-pests.     

The effects of foods consumed after adult eclosion on the mate-searching behavior and feeding preferences of the white-spotted longicorn beetle Anoplophora malasiaca (Coleoptera: Cerambycidae)

The effects of changes in host plants on the mate-searching behavior and feeding preferences of the white-spotted longicorn beetle Anoplophora malasiaca (Thomson) (Coleoptera: Cerambycidae) were examined. All individuals were raised on the same artificial diet until they became pupae. Analysis of the mate-searching behavior of the males showed that many more newly emerged males were attracted to the odor of the artificial diet than to an unbaited control. We prepared three groups of beetles and fed each group on different host plants for one week. The host plants used included the following: an artificial diet (containing Morus alba Linné), Citrus unshiu Marc. branches, and Vaccinium spp. branches. The mate-searching behavior of the males changed in relation to the plant supplied for feeding. Simultaneously, the preference among the three host plants was tested. The newly emerged males preferred the artificial diet. After a week of feeding on one of the three plants, however, the adult males selected and consumed significantly more of the plant that they had just experienced than the other plants. These results suggest that the male mate-location cue can be acquired after adult eclosion. In addition, the male beetles are capable of changing their host-plant preference. If they do so, they use different odor cues for mate location. Newly emerged A. malasiaca females showed no preference for their first choice of food among the three host plants presented, whereas the consumption was significantly larger on C. unshiu branches. After one week of feeding on different host plants, females chose their host plant after the adult stage as well as C. unshiu, but consumed mostly C. unshiu. These results suggest that the food preferences of females are different from those of males. The behavior of females may not be affected by chemical signals from their original host-plant species (as pupae) or from the host-plant species acquired when they emerge as adults.     

Proteomics Indicators of the Rapidly Shifting Physiology from Whole Mountain Pine Beetle,Dendroctonus ponderosae (Coleoptera: Curculionidae), Adults during Early Host Colonization

We developed proteome profiles for host colonizing mountain pine beetle adults, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae). Adult insects were fed in pairs on fresh host lodgepole pine, Pinus contorta Dougl. ex Loud, phloem tissue. The proteomes of fed individuals were monitored using iTRAQ and compared to those of starved beetles, revealing 757 and 739 expressed proteins in females and males, respectively, for which quantitative information was obtained. Overall functional category distributions were similar for males and females, with the majority of proteins falling under carbohydrate metabolism (glycolysis, gluconeogenesis, citric acid cycle), structure (cuticle, muscle, cytoskeleton), and protein and amino acid metabolism. Females had 23 proteins with levels that changed significantly with feeding (p<0.05, FDR<0.20), including chaperones and enzymes required for vitellogenesis. In males, levels of 29 proteins changed significantly with feeding (p<0.05, FDR<0.20), including chaperones as well as motor proteins. Only two proteins, both chaperones, exhibited a significant change in both females and males with feeding. Proteins with differential accumulation patterns in females exhibited higher fold changes with feeding than did those in males. This difference may be due to major and rapid physiological changes occurring in females upon finding a host tree during the physiological shift from dispersal to reproduction. The significant accumulation of chaperone proteins, a cytochrome P450, and a glutathione S-transferase, indicate secondary metabolite-induced stress physiology related to chemical detoxification during early host colonization. The females'' activation of vitellogenin only after encountering a host indicates deliberate partitioning of resources and a balancing of the needs of dispersal and reproduction.     

Feeding preferences and performance of an aquatic lepidopteran on macrophytes: plant hosts as food and habitat

Although host preferences in phytophagous insects may be generated by several factors, few studies have simultaneously examined several potential host choice determinants. In this study we tested the impact of the following potential host choice determinants on host preference of the semi-aquatic lepidopteran Munroessa gyralis (Pyralidae): growth on different host plants; protein content, polyphenolic content, toughness, and chemical extracts of different host plants; prior feeding experience; and predation pressure on the caterpillar by fishes. Two water lilies, Brasenia schreberi and Nymphaea odorata, were preferred in cafeteria-style feeding experiments over 14 other species of vascular plants. The most preferred water lily (Brasenia) also afforded the fastest growth relative to three other species on which growth was measured. Feeding preferences across species were unrelated to protein content, polyphenolic content, or toughness. Domiciles constructed by caterpillars from leaf fragments were protective from field assemblages of fishes, but domiciles made from preferred or unpreferred host species conferred no significant protection from fish in the laboratory. Caterpillars responded positively to chemical cues of water lilies, and prior feeding experience increased preference for an otherwise unpreferred water lily (Nuphar advena) within the life-span of individual caterpillars. M. gyralis is a generalist herbivore exhibiting modest preference induction and preferences for and among members of the family Nymphaeaceae. Our results suggest that relative growth rates, chemical cues, and previous feeding experience are important factors determining feeding preference. Protein content, polyphenolic content, and toughness appear less important, and the importance of fish predators remains in question. As pupation seems to occur exclusively on Nymphaea, we suggest that host use may be restricted due to life-stage-specific developmental constraints that are not apparent from the results of growth or preference assays. It is currently unknown how often specific life-stages may restrict host use, but our work suggests this as a potentially important area of inquiry.     

Epiphytes on the rocky intertidal red alga RhodomelaLarix (Turner) C. Agardh: Negative effects on the host and food for herbivores?

The diversity of epiflora and fauna associated with a dominant turf-forming alga was examined in intertidal communities on the central Oregon coast. Epiphytes associated with the red alga, Rhodomelalarix (Turner) C. Agardh, were examined by surveying intertidal areas for the presence of epiphytes, and by following changes in epiphyte cover in marked quadrats of R. larix. The alga is host for at least 17 species of sessile plants and animals. To determine the role of some of the larger epiphytes in the community, Rhodomela plants were marked and monitored and herbivore feeding was examined. Data suggest that epiphytes decrease the growth rate of their host, increase the probability of axis breakage and decrease reproductive output. Epiphytes provide food for littorine snails and gammarid amphipods that live in the beds of the plant. Amphipods were found to decrease epiphyte cover on R. larix in laboratory tanks, suggesting that these herbivores may have beneficial effects on the host plant.     

The 3D Structure of the Apical Complex and Association with the Flagellar Apparatus Revealed by Serial TEM Tomography in Psammosa pacifica,a Distant Relative of the Apicomplexa

The apical complex is one of the defining features of apicomplexan parasites, including the malaria parasite Plasmodium, where it mediates host penetration and invasion. The apical complex is also known in a few related lineages, including several non-parasitic heterotrophs, where it mediates feeding behaviour. The origin of the apical complex is unclear, and one reason for this is that in apicomplexans it exists in only part of the life cycle, and never simultaneously with other major cytoskeletal structures like flagella and basal bodies. Here, we used conventional TEM and serial TEM tomography to reconstruct the three dimensional structure of the apical complex in Psammosa pacifica, a predatory relative of apicomplexans and dinoflagellates that retains the archetype apical complex and the flagellar apparatus simultaneously. The P. pacifica apical complex is associated with the gullet and consists of the pseudoconoid, micronemes, and electron dense vesicles. The pseudoconoid is a convex sheet consisting of eight short microtubules, plus a band made up of microtubules that originate from the flagellar apparatus. The flagellar apparatus consists of three microtubular roots. One of the microtubular roots attached to the posterior basal body is connected to bypassing microtubular strands, which are themselves connected to the extension of the pseudoconoid. These complex connections where the apical complex is an extension of the flagellar apparatus, reflect the ancestral state of both, dating back to the common ancestor of apicaomplexans and dinoflagellates.