The Immobilization Antigens of Tetrahymena thermophila Are Glycoproteins

ABSTRACT The four immobilization antigens controlled by the SerH locus in Tetrahymena thermophila have been isolated and partially characterized (Doerder, F. P. & Berkowitz, M. S. 1986. Purification and partial characterization of the H immobilization antigens of Tetrahymena thermophila. J. Protozool. , 33 :204–208). We show here, using immunoprecipitation and electrophoresis after labeling with ³⁵S-methionine, ¹⁴C-mannose, ¹⁴C-glucosamine, and N-Acetyl- d -[1-³H]glucosamine, that these proteins are glycosylated. We suggest the immobilization antigens in Tetrahymena may be anchored to the surface membrane by phosphatidylinositol glycans.     

Phylogenetically distant symbiotic microorganisms reside in Glossina midgut and ovary tissues

Abstract. Many blood-feeding insects, including tsetse flies (Diptera: Glossinidae), harbour intracellular bacterial symbionts. Using isolates from tissues of several Glossina species and diagnostic DNA oligonucleotide primers, a polymerase chain reaction (PCR) based assay was designed to identify symbiotic bacteria. Those inhabiting the midgut of Glossina were found to belong to the gamma subdivision, whereas ovarian Proteobacteria were of the alpha subdivision - probably genus Wolbachia (Rickettsiaceae). The presence of Wolbachia-like Rickettsia in the ovaries of G. morsitans subspecies may help to explain the maternally inherited incompatibility of some crosses within this species.     

Western Snowy Plovers Charadrius alexandrinus nivosus select nesting substrates that enhance egg crypsis and improve nest survival

Predation is an important cause of nest failure for many birds and has shaped the life‐history characteristics of many species, especially ground‐nesting shorebirds. We examined nesting success, causes of clutch failure and nest survival in relation to variation in substrate characteristics in a colour‐marked population of Western Snowy Plovers Charadrius alexandrinus nivosus breeding on riverine gravel bars in coastal northern California. Plovers experienced higher nesting success on gravel bars than on nearby beaches, which were characterized by more homogeneous, sandy substrates. On gravel bars, Plovers nested in habitats characterized by large, heterogeneous substrates, with more egg‐sized stones, compared with random sites. Egg crypsis, as indexed by time required of a naïve observer to detect a nest, increased with number of egg‐sized substrates. Nest survival correlated negatively with heterogeneity of substrates and positively with the number of egg‐sized stones. Consistently high nesting success of Plovers on gravel bars indicates that this high‐quality habitat deserves special management considerations given the species’ threatened status.