Alloreactivity against IE-encoded antigens: evidence of the discrepancy between graft rejection and reactivity of IE-reactive T cells.

Participation of IE antigens (Ag) in immune response as the transplantation Ag was examined. IE- B10.A(4R)(4R; Kk, IAk, IE-, Db) mice could not reject skin graft from IE Ag alone-disparate B10.A(2R) (2R; Kk, IAk, IEk, Db) mice despite intravenous (iv) injection of 2R spleen cells (SC) before or after skin grafting, indicating that graft rejection could not be caused across IE Ag-barrier alone. Furthermore, 4R SC could not induce lethal graft-versus-host disease (GVHD) in supralethally (950 rad) irradiated 2R mice. On the other hand, infiltration of lymphoid cells was observed at the site of transplanted 2R skin in 4R mice. SC of 4R mice unprimed or primed with 2R skin or 2R SC showed the capability to proliferate in vitro in response to 2R Ag. In immunofluorescence analysis of lymph node cells (LNC) of 4R mice injected iv with 2R SC 7 days earlier, IE-reactive CD4+Vbeta 11+ T cells did not change in number, but slightly increased the expression of interleukin-2 receptor (IL-2R). In 2R mice irradiated with 670 rad and injected iv with 4R SC 7 days earlier, 4R-derived CD4+V beta 11+ T cells proliferated, changed to blastoid form, and showed a markedly increased expression of IL-2R. To further investigate the influence of IE alloantigens on transplantation immunity, IL-2 production and anti-class I CTL activity were assayed. The 4R SC capable of recognizing IEk and Dk Ag of B10.BR (Kk, IAk, IEk, Dk) generated levels of both IL-2 and CTL activities higher than those of 2R SC capable of recognizing Dk Ag alone. These results strongly suggest that IE alloantigens indirectly act as the transplantation Ag by the stimulation of IE-reactive CD4+ helper T cells resulting in the differentiation of class I-restricted CD8+ T cells.     

New mutation affecting the synthesis of some membrane proteins and sporulation in Bacillus subtilis.

A new mutation, mpo, which affects the synthesis of some membrane proteins and sporulation in Bacillus subtilis was identified. The mpo mutation was tightly linked to the overproduction of membrane proteins MP32 and MP18 (molecular weights of 32,000 and 18,000, respectively) and the temperature-sensitive sporulation phenotype. Genetic analysis showed that the mpo mutation maps between the spoIIIB and lys loci.     

Tail-associated structural protein gp61 of Staphylococcus aureus phage φMR11 has bifunctional lytic activity

A tailed bacteriophage, φMR11 (siphovirus), was selected as a candidate therapeutic phage against Staphylococcus aureus infections. Gene 61, one of the 67 ORFs identified, is located in the morphogenic module. The gene product (gp61) has lytic domains homologous to CHAP (corresponding to an amidase function) at its N-terminus and lysozyme subfamily 2 (LYZ2) at its C-terminus. Each domain of gp61 was purified as a recombinant protein. Both the amidase [amino acids (aa) 1–150] and the lysozyme (aa 401–624) domains but not the linker domain (aa 151–400) caused efficient lysis of S . aureus . Immunoelectron microscopy localized gp61 to the tail tip of the φMR11 phage. These data strongly suggest that gp61 is a tail-associated lytic factor involved in local cell-wall degradation, allowing the subsequent injection of φMR11 DNA into the host cytoplasm. Staphylococcus aureus lysogenized with φMR11 was also lysed by both proteins. Staphylococcus aureus strains on which φMR11 phage can only produce spots but not plaques were also lysed by each protein, indicating that gp61 may be involved in 'lysis from without'. This is the first report of the presence of a tail-associated virion protein that acts as a lysin, in an S. aureus phage.     

Polyamines in Rhizobium, Bradyrhizobium, Azorhizobium and Argobacterium

Abstract Eighteen strains of Rhizobium including four species, R. leguminosarum, R. meliloti, R. loti and R. fredii , nine strains of Bradyrhizobium japonicum and three strains of Azorhizobium caulinodans contained putrescine and honospermidine as major polyamines. All these nodulating N₂-fixing rhizobia lack spermidine. Spermidine and cadaverine were present only in a limited number of R. meliloti and B. japonicum . Polymanine-synthetic activity was not affected by the differences in ability to produce phytoxine (rhizobitoxine and dihydrorhizobitoxine) H₂-uptake-hydrogenation in the organisms. Putrescine and homospermidine were major polyamined in a strain of Agrobacterium rhizogenes . All the eight strains of Agrobacterium tumefaciens as well as A. rubi, A. radiobacter and two other strains of A. rhizogenes contained putrescine and spermidine as major polyamines and homospermidine and spermine (and thermospermine) as minor polyamines.     

A comparison of the subcellular distribution of 5′-nucleotidase, (Na+K+)-ATPase and adenyl cyclase in beef thyroid gland

The validity of 5′-nucleotidase as a plasma membrane marker enzyme in beef thyroid has been tested by comparing the subcellular distribution of its activity to that of (Na⁺K⁺)-activated ATPase and adenyl cyclase. The specific activity and total activity of (Na⁺K⁺)-ATPase and adenyl cyclase were greatest in the 1000 × g (“nuclear”) and 33 000 × g (“mitochondrial and lysosomal”) fractions. In contrast, 5′-nucleotidase activity was concentrated in the 165 000 × g (“microsomal”) pellet and supernatant. Partially purified plasma membranes were separated from the 1000 (N₂), 30 000 (M₂) and 165 000 × g (P₂) pellets by discontinuous sucrose gradient centrifugation. Again a discordant distribution of these enzyme activities was observed. (Na⁺K⁺)-ATPase specific activity was increased approximately 30-fold over the homogenate in Fractions N₂ and M₂. Basal, thyroid-stimulating hormone-and fluoride-stimulated adenyl cyclase activities were concentrated in the same fractions. 5′-Nucleotidase activity was preferentially located in M₂ and P₂. These differences in distribution pattern suggest that 5′-nucleotidase activity is not uniquely located in the plasma membrane in the thyroid.     

Planned reproduction of the house musk shrew (Suncus murinus)

To investigate methods for the planned reproduction of the house musk shrew (Suncus murinus), increased reproduction was attempted from May through August, 1980 using 13 females and 13 males obtained from the breeding colony in the Laboratory of Animal Genetics, Faculty of Agriculture, Nagoya University. As a result, a reproduction colony consisting of 128 females and 60 males was formed in September, 1981. This was followed by repeated selective culling until a planned reproduction system with monthly production of over 100 pups was established in December, 1981. The production results for one year, 1982, showed that among the 994 females mated, there was a gestation rate of 74.1%, a parturition rate of 89.8%, average litter size of 3.5, a weaning rate of 77.2%, and a productive index of 1.8. A total of 1,780 weanlings was obtained and stable production throughout the year was achieved.     

Experimental Approach Reveals the Role of alx1 in the Evolution of the Echinoderm Larval Skeleton

Over the course of evolution, the acquisition of novel structures has ultimately led to wide variation in morphology among extant multicellular organisms. Thus, the origins of genetic systems for new morphological structures are a subject of great interest in evolutionary biology. The larval skeleton is a novel structure acquired in some echinoderm lineages via the activation of the adult skeletogenic machinery. Previously, VEGF signaling was suggested to have played an important role in the acquisition of the larval skeleton. In the present study, we compared expression patterns of Alx genes among echinoderm classes to further explore the factors involved in the acquisition of a larval skeleton. We found that the alx1 gene, originally described as crucial for sea urchin skeletogenesis, may have also played an essential role in the evolution of the larval skeleton. Unlike those echinoderms that have a larval skeleton, we found that alx1 of starfish was barely expressed in early larvae that have no skeleton. When alx1 overexpression was induced via injection of alx1 mRNA into starfish eggs, the expression patterns of certain genes, including those possibly involved in skeletogenesis, were altered. This suggested that a portion of the skeletogenic program was induced solely by alx1. However, we observed no obvious external phenotype or skeleton. We concluded that alx1 was necessary but not sufficient for the acquisition of the larval skeleton, which, in fact, requires several genetic events. Based on these results, we discuss how the larval expression of alx1 contributed to the acquisition of the larval skeleton in the putative ancestral lineage of echinoderms.