Spatial vision in binocular and monocular common field grasshoppers (Chorthippus brunneus)

Abstract The ability of the common field grasshopper Chorthippus brunneus to discriminate between different distances under binocular and monocular stimulus conditions is investigated based upon the peering‐jump behaviour. The results show that information obtained from only one eye is sufficient for the grasshopper to determine the jump direction and distance. However, information obtained from both eyes is advantageous for relative distance determination. It is hypothesized that the motion parallax signals from the left and right eye may be summed, thus improving performance. There is no behavioural evidence of a more complex correlation of the information from the two eyes.     

Epistylis helicostylum n. sp., a New Peritrichous Ciliate with an Allometric Stalk Formation

SYNOPSIS. A new peritrichous ciliate, Epistylis helicostylum n. sp. is described. It lives attached to the extremities of the ostracod Eucypris virens as its specific symphoriont. A spiral structure forming a protective theca for the colony of daughter animals is produced by the allometric growth of the outer sheath of the stalk. The whole process of its formation is described.     

Observations on the Ultrastructure of the Buccal Apparatus in Thigmotrich Ciliates and their Bearing on Thigmotrich-Peritrich Affinities*

SYNOPSIS. In the first use of electron microscopy in a comparative investigation of ciliates belonging to the order Thigmotrichida, ultrastructural data were collected on ciliary organelles of the buccal area. Species studied included members of the genera Ancistrum and Boveria. Analysis of the findings suggest close affinities between thigmotrich and peritrich ciliates. Further comparison with studies on hymenostome (sensu lato) ciliates supportes the hypothesis of a common ancestral stock in the phylogenetic history of all 3 of these groups. Structures very likely homologous in species of hymenostomes, thigmotrichs, and peritrichs include: the undulating membrane, the polykineties, the oral ribs, the filamentous reticulum, and a small field of barren kinetosomes.     

Brooklynella hostilis n. g., n. sp., a Pathogenic Cyrtophorine Ciliate in Marine Fishes*

SYNOPSIS. Brooklynella hostilis is a new genus and new species of highly lethal Chilodonella-like parasite in the gills of marine fishes. It differs from other dysteriid ciliates by a combination of these features: 1) posterior-ventral adhesive apparatus consisting of a single glandular organelle that lacks a distinct discharging canal or podite; 2) the kinetosomes cover the entire ventral surface, except the left posterior portion of the body; the outer right kinety is divided into 2 segments; the middle postoral kinetyues as a row of kinetosomes without cilia around the glandular organelle; 3) there are never more than 9 nematodesmata; and 4), there are numerous small micronuclei. The lesions caused by the infection vary from a mild inflammatory reaction to extreme tissue damage resulting in severe hemorrhages, desquamation, and fusion of the gill lamellae.     

Cloning and Characterization of New Repetitive Sequences in Field Bean (Vicia faba L.)

Annals of Botany83: 535–541, 1999 It is regretted that Figure 1 of this paper was incorrect; itshould have appeared as follows: Fig. 1. Genomic organization of new repetitive sequences. Southernblots of field bean genomic DNA digested using various restrictionenzymes (H, Hind III; Hc, Hinc II; T,Taq I; A, Alu I; R, RsaI; M, Mbo I; F, Fok I) were probed with the individual repeats.The bands from which the sequences were isolated are markedby arrows. The bands from which full length sequence of T133and TIII17 repeats were isolated are marked by asterisks.     

Monoclonal Antibodies Identify a Subset of Dense Granules in Cryptosporidium parvum Zoites and Gamonts

ABSTRACT. Two monoclonal antibodies raised against purified oocysts and excysted sporozoites of Cryptosporidium parvum identified antigens located in the anterior half of sporozoites by indirect immunofluorescence microscopic assay. The monoclonal antibodies also reacted with Triton X-100-insoluble antigens of asexual and sexual stage parasites developing in epithelial cells in vitro and identified a 110 kilodalton antigen on immunoblots of sodium dodecyl sulfate-extracted oocysts. Immunoblotting reactivity was abolished by prior treatment of blotted antigen with periodic acid suggesting that the monoclonal antibodies recognize a carbohydrate or carbohydrate-dependent epitope(s). By immunoelectron microscopy, the antibodies reacted with a family of small, electron-dense granules located predominantly in the central region of merozoites and also with a population of cytoplasmic inclusions in macrogamonts. In addition, the monoclonal antibodies prominently labeled the parasitophorous vacuole membrane of all intracellular stages examined suggesting that the corresponding antigen(s) may be exocytosed from the granules to become associated with Triton X-100-insoluble components of the vacuolar membrane or cytoskeleton.     

Etude Cytologique, Systématique et Pathologique d'Ichtyobodo necator (Henneguy, 1883) Pinto, 1928 (Zooflagelle)

SYNOPSIS. The free form of Ichtyobodo necator is typically quadrangular, with rounded corners, and flattened dorso-ventrally. Its dorsal surface is strongly convex and its ventral surface somewhat concave. A longitudinal groove traverses the posterior 2/3 of the ventral surface near its right margin. The part of the organism anterior to the groove is rather thick; that containing the depression thins out progressively toward the posterior end. Most of the organelles are in the major part of the cytoplasm to the left of the groove. Anteriorly this depression continues into a rather short canal. Two (4 in predivision stages) flagella originate near the anterior end of the canal, from which they run posteriorly. The cytostome is also near the anterior part of the canal. The cytostome, canal, and cell membrane are reinforced by microtubules. The chondriome, undoubtedly represented by a single very elongated mitochondrion, contains numerous dilated areas rich in deoxyribonucleic acid. The fixed form of the flagellate is highly modified. Its anterior part becomes attached to the host cell by forming a plate. A type of sucking organelle that contains the cytostome forms from the plate and penetrates the host cell. I. necator belongs in the family Bodonidae. RESUME La forme libre d'Ichtyobodo necator est quadrangulaire avec des angles arrondis, et présente un aplatissement dorsoventral. Sa surface dorsale est fortement convexe et sa surface ventrale légèrement concave. Une gouttiére longitudinale traverse les 2/3 postérieurs de la face ventrale sur le bord droit. La région cellulaire antérieure à, la gouttiére est plus épaisse que celle qui contient la dépression et s'amincit progressivement vers la partie terminale. La plupart des organites cellulaires occupent la partie gauche de la cellule. Dans la région antérieure la gouttiére se prolonge par un canal assez court. Deux (quatre dans les stades de prédivision) flagelles partent de ce canal et se dirigent vers la région postérieure. Le cytostome est également localisé près de la région antérieure du canal. Le cytostome, le canal et la membrane cellulaire sont jouxtés de microtubules. Le chondriome, sans doute représenté par une seule mitochondrie très allongée, présente de nombreuses dilatations riches en acide désoxyribonucléique. La forme fixée du flagellé est très modifiée. Sa partie antérieure adhère à la cellule hǒte par l'intermédiaire d'un plateau. Une sorte de suçoir, qui contient le cytostome, se forme à partir de ce plateau et pénètre dans la cellule hǒte. Ichtyobodo necator appartient à la famille des Bodonidae.