Impaired Antigen Specific Responses and Enhanced Polyclonal Stimulation in Mice Infected with Ehrlichia muris

The immune status of BALB/c mice infected by intraperitoneal inoculation with Ehrlichia muris was examined. The level of E. muris infection in both peritoneal cavity and spleen was greatest at day 10 postinoculation (PI). Thereafter, the infection level was dramatically reduced while the organism persisted for up to 400 days PI. The greatest intraperitoneal infiltration of leukocytes, splenomegaly, and leukocytosis were observed on days 10, 15, and 20 PI, respectively. Infected mice developed marked hypergammaglobulinemia of IgG and IgM that peaked at day 20 PI; however, IgA plummeted at day 15 PI. Of IgG, G2a and G3 increased while G1 and G2b remained constant. Despite hypergammaglobulinemia, both IgG and IgM antibody titers against E. muris were very low throughout the 30-day study. Antibody development and plaque-forming cells against sheep red blood cells (SRBC) were abolished when the antigen was inoculated on day 10 PI. IgM antibody development against SRBC was more severely inhibited than IgG antibody development. However, when mice were immunized with SRBC prior to E. muris infection, antibody development against SRBC was not reduced. Delayed type hypersensitivity reaction to dinitrofluorobenzene was also maximally inhibited when the antigen was administered on day 10 PI. The IFN-γ level in the blood was maximal at day 10 PI. These results indicate that although the vigorous polyclonal activation and protective IFN-γ responses occurred by day 10 PI—which cleared most of the ehrlichial infection—antigen-specific immune stimulation was impaired primarily at the level of antigen-priming at peak parasitemia.     

Effect of separation distance on isolation call structure in squirrel monkeys (Saimiri sciureus)

Isolation calls of captive squirrel monkeys were recorded by separating infants from their natal group members and then permitting vocal contact between the “lost” baby and the group at systematically varied distances. Separated infants gave longer calls at greater separation distances from their natal group members, and responding adults and juveniles similarly extended the length of their vocalizations. In the longer variants, a highfrequency element was prolonged, which is considered to be an example of the net advantage of a “frequency window” in the ambient noise of environments.     

Control of the localization and function of a miRNA silencing component TNRC6A by Argonaute protein

GW182 family proteins play important roles in microRNA (miRNA)-mediated RNA silencing. They directly interact with Argonaute (Ago) proteins in processing bodies (P bodies), cytoplasmic foci involved in mRNA degradation and storage. Recently, we revealed that a human GW182 family protein, TNRC6A, is a nuclear-cytoplasmic shuttling protein, and its subcellular localization is regulated by its own nuclear localization signal and nuclear export signal. Regarding the further controlling mechanism of TNRC6A subcellular localization, we found that TNRC6A protein is tethered in P bodies by direct interaction with Ago2 under Ago2 overexpression condition in HeLa cells. Furthermore, it was revealed that such Ago proteins might be strongly tethered in the P bodies through Ago-bound small RNAs. Thus, our results indicate that TNRC6A subcellular localization is substantially controlled by the interaction with Ago proteins. Furthermore, it was also revealed that the TNRC6A subcellular localization affects the RNA silencing activity.     

The bacterial outer membrane protein that reacts with anti-HLA-B27 antibodies is the OmpA protein

A bacterial outer membrane protein of 35-kDa Mr has been reported to react with several anti-HLA-B27 mAb. Here, we demonstrated that this protein showed the heat-modifiability of the OmpA protein during SDS-PAGE. Further, the protein was not detected in mutants of Escherichia coli in which the expression of the OmpA protein has been suppressed. The protein would be reexpressed when one of the mutants was transformed with an expression vector carrying the OmpA gene. Finally, the identity of the reactive protein to OmpA protein was verified by homology in amino acid sequences. An NH2-terminal fragment of this protein was generated by tryptic digestion. Inasmuch as this was unreactive with the anti-HLA-B27 antibody, we concluded that the carboxyl-terminus contributed directly or indirectly to the reactive domain.     

Gonadotroph-rich cell lines derived from pituitary clonal cells (2A8) grafted under the kidney capsule

Summary Gonadotroph-rich cell lines were established from multipotential pituitary clonal cells (2A8) which were implanted under kidney capsule of hypophysectomized female rats. These cell lines secrete gonadotrophins (FSH and LH) continuously over two months after establishment; LHRH stimulated the secretion of hormones into the culture medium. Many of the cells reacted immunohistochemically to antiserum to FSH or LH, while a small number reacted to antiserum to prolactin or TSH. They did not contain normal secretory granules such as those of gonadotrophs in vivo.Supported by USPHS Grant HD 11826 and NIH Grant P30 HD 10202. The authors wish to thank James Chambers (Immunocytochemistry), and Pat Koym and John Rhode (Radioimmunoassay) for their excellent technical assistance. We also express our thanks to NIAMDD for providing pituitary hormones     

Ultrastructure of microtubules in dermal melanophores and spinal nerve of the Antarctic teleost Pagothenia borchgrevinki

Summary The antarctic teleost, Pagothenia borchgrevinki inhabits the Antarctic Ocean where the water temperature remains around -1.9° C throughout the year. Dermal melanophores of this fish respond within minutes to epinephrine and theophylline with melanosome aggregation and dispersion, respectively. Numerous cytoplasmic microtubules are present in these cells despite the low environmental temperature. In longitudinal profiles, many microtubules are twisted, beaded and sometimes even branched. In cross sections, C-, U-, S-, 6- and other irregularly shaped tubules are observed. Nocodazole partially disrupts microtubules and inhibits epinephrine-induced pigment aggregation. Pigment movements are also prevented by erythro-9-[3-(2-hydroxynonyl)] adenine. Although the participation of these incomplete microtubules in cell motility remains uncertain, the results indicate that this fish has a cold-resistant microtubule system on which melanosome movements depend. Unlike those in melanophores, microtubules in the axons of spinal nerves are of uniform thickness and often contain an electron-dense core in the center.     

A Method for Embedding Thin Membranes in Historesin

A method is described for flat-embedding thin membranous tissues in Historesin. It allows easy orientation for sectioning large areas parallel to the surface. Selected fields can be monitored from the unfixed specimen, throughout preparation, to mounting on the microscope slide. For cross-sectioning, the flat-embedded tissue can be stacked and re-embedded to increase the amount of material examined per section.