Synthesis and deposition of oocyte envelopes in the Colorado beetle,Leptinotarsa decemlineata say

Summary Electron microscopical and autoradiographic methods demonstrate that the secretion vesicles (SV), which are condensed by the Golgi-complexes of the follicle cells of the Colorado beetle, contain proteins which can be labelled with ³H-leucine. The labelled proteins are transported to the oocyte during vitellogenesis. At the end of yolk deposition, a few SV, situated just above the microvilli, disintegrate and give rise to the two layers of the vitelline membrane (VM). During the laying down of the VM or perhaps at a slightly earlier stage a layer is deposited beneath the basement membrane of the follicle cells. This layer may be important in inducing the formation of the egg membranes. Once the VM has formed, the follicle cells degenerate completely. The chorionic inner layer arises from the breakdown of SV, while the chorionic outer layer is formed from the degenerated follicle cells.Dr. A. de Loof gratefully acknowledges a mandate as Aangesteld Navorser of the National Foundation of Scientific Research in Belgium. He also thanks Prof. Dr. A. Gillard for his very helpfull criticism, Dr. W. Mordue (Cambridge) for his help in correcting the language, Prof. Dr. A. Lagasse, for supplying facilities in his laboratory of EM, Mr. W. Bohyn for operating the EM and Mr. G. Maes for photography. Special thanks to Drs. G. Vrensen (Nijmegen) for the introduction in autoradiographic techniques.     

Immunosome technology to improve antigen presentation for efficient and safe viral vaccines

The role of liposomes in antigen presentation and in induction of humoral and cell-mediated immune responses has been investigated by anchoring viral envelope glycoproteins into the phospholipidic bilayer of preformed liposomes to produce Immunosomes. Using purified glycoproteins of three different enveloped viruses, it was found that in mice immunosomes induced high titres of neutralizing antibodies, whereas equal amounts of the purified glycoproteins alone failed to induce or induced much lower neutralizing antibodies. Similarly, immunosomes induced in vaccinated animals antigenspecific interleukin-2 production upon in vitro restimulation with the same antigen, whereas no secondary response was observed in animals vaccinated with equal amounts of the free antigen. Finally, influenza and rabies immunosomes were shown to be efficient in protecting animals from a challenge with the corresponding virulent strain.     

哺乳动物细胞分泌的乙型肝炎病毒表面抗原的理化和生物学性状

研究了哺乳动物细胞分泌的乙型肝炎病毒表面抗原(HBsAg)纯品的理化及生物学性状。结果表明:此种HBsAg在CsCl中的浮力密度是1.21g/cm~3;快速液相层析的SuperoseHR6层析柱上呈现3个峰,中间是一个主峰,两侧各一小峰;经Mono Q柱层析呈现一个对称峰,证明了HBsAg颗粒所带电荷的均一性;以SDS-PAGE和凝胶扫描方法分析HBsAg的多肽,P23、gp27和gp30各占65％、20％和10％,另有5％的二聚体存在;N-末端的氨基酸序列与转入细胞的目的基因所编码的序列相同;HBsAg在4℃和-20℃储存较稳定,室温条件保存时间不宜过长。动物实验证明:用与血源HBsAg疫苗同等剂量的基因工程HBsAg疫苗接种Balb/C小鼠,可获得比血源疫苗高2.64倍的免疫效果。此外,经过福尔马林处理的疫苗较未处理的疫苗有较强的免疫原性。     

Murine T cell clones specific for Hymenolepis nana: generation and functional analysis in vivo and in vitro.

To examine the role of the T cell in protective immunity to Hymenolepis nana, H. nana-specific clonal lymphocytes were generated from mesenteric lymph nodes of BALB/c mice infected with H. nana, and some of their functions were analyzed in vitro and in vivo. Following limiting dilution techniques, five clones were generated from mesenteric lymph node cell populations. All of these clones expressed the L3T4⁺, Lyt-2.2⁻ phenotype and proliferated in vitro in response to soluble egg antigen of H. nana. Of five clones, three secreted interleukin 2 (IL-2) and interferon-γ (IFN-γ) after stimulation with egg antigen. Furthermore, these three clones conferred local delayed-type hypersensitivity to egg antigen. The remaining two clones produced interleukin 4 (IL-4) in response to egg antigen, and could not mediate local delayed-type hypersensitivity. Adoptive transfer experiments using clonal lymphocytes were also undertaken in an attempt to define cell types involved in protective immunity. Clonal lymphocytes secreting both IL-2 and IFN-γ transferred protective immunity, equivalent to that obtained by non-cultured-sensitized mesenteric lymph node cells. They were effective in very small numbers. However, clonal lymphocytes that secreted IL-4 did not transfer protective immunity. These results suggest that helper T lymphocytes, especially the Th1 subtype, are involved in protective immunity against H. nana.     

Sequence analysis of the Legionella micdadei groELS operon

A 2.7 kb DNA fragment encoding the 60 kDa common antigen (CA) and a 13 kDa protein of Legionella micdadei was sequenced. Two open reading frames of 57,677 and 10,456 Da were identified, corresponding to the heat shock proteins GroEL and GroES, respectively. Typical -35, -10, and Shine-Dalgarno heat shock expression signals were identified upstream of the L. micdadei groEL gene. Further upstream, a poly-T region, also a feature of the sigma 32-regulated Escherichia coli groELS heat shock operon, was found. Despite the high degree of homology of the expression signals in E. coli and L. micdadei, Western blot analysis with an L. micdadei specific anti-groEL antibody did not reveal a significant increase in the amount of the GroEL protein during heat shock in L. micdadei or in the recombinant E. coli expressing L. micdadei GroEL.     

The EPR spectrum of cytochrome b-563 in the cytocrhome bf complex from spinach: (1993) FEBS Letters 164, 71–74

Blood group H antigen with globo-series structure, reacting with the monoclonal antibody MBrl, was isolated and characterized from human blood group O erythrocytes. The structure was identified by methylation analysis, direct probe mass spectrometry, and ¹H-nuclear magnetic resonance spectroscopy as shown below: Fucαl → 2Galβl → 3GalNAcβl → 3Galαl → 4Galβl → 4Glcβl → 1Cer     

Differential phosphorylation of murine class I major histocompatibility antigens

Recent studies have shown that the H-2K and H-2D transplantation antigens are expressed differentially in different tissues of mouse. Our previous investigations also established that in thioglycolate-stimulated peritoneal macrophages the H-2D^k antigen exists in distinct cell surface and intracellular forms. These two forms are glycosylated differently. In this report, we have found that (1) H-2D^k antigen is phosphorylated whereas H-2K^k antigen is not, and (2) only the cell surface form of H-2D^k antigen is phosphorylated in thioglycolate-stimulated macrophages derived from C3H/Heha mice. This differential phosphorylation of H-2 antigens will provide a model system for further studies on the molecular mechanism and function of phosphrrylation of H-2 antigens.     

Effects of norepinephrine on neonatal rat cardiocyte growth and differentiation

Summary Norepinephrine stimulates the growth in size of nondividing neonatal cardiocytes. During this time the neonatal cardiocyte is in a period of transition in which the cell can synthesize DNA and yet does not divide. Because the cell undergoes karyokinesis without cytokinesis the objective of this study was to determine whether the norepinephrine-induced growth in size of the neonatal cardiocyte was accompanied by an increase in a) the number of cardiocytes synthesizing DNA, b) the number of binucleate cardiocytes, and c) organized myofibrils. One- to four-d-old neonatal rat heart cells were isolated and placed in serum-free medium which was then supplemented with serum, norepinephrine, norepinephrine plus propranolol, or isoproterenol. After 4 d the number and size of the cells was determined using a Coulter counter. In other cultures cardiocytes were fixed on Days 0, 1, 2, and 4, and an increase in the number of binucleate cardiocytes was found in all treatment groups including controls. However, the rate of binucleation was faster in the norepinephrine group. It was also determined by proliferating cell nuclear antigen (PCNA) antibody staining that by Day 4, over 50% of the cardiocytes were in the cell cycle. The percentage of cells in which PCNA could be detected was higher in the norepinephrine and norepinephrine plus propranolol groups. Furthermore, there was a concomitant increase in the amount and organization of myofibrils in the catecholamine-treated cardiocytes. Supported in part by grant No. HL 29351 from the National Institutes of Health, by a grant from the American Heart Association and with the support of the Southeastern Pennsylvania and Pennsylvania Affiliates of the American Heart Association.     

Cleavage of the O antigen 4,5,12 of Salmonella typhimurium by hydrofluoric acid

The effect of hydrofluoric acid (aqueous 48% HF) upon different lipopolysaccharides (LPS) was studied, employing conditions (48 h at + 4°C) that are commonly used to dephosphorylate LPS. From the LPS of Salmonella typhimurium having the O antigen 4,5,12 almost all of the O-antigenic sugars (Abe, Gal, Glc, Man, Rha) were liberated in dialysable form, whereas the saccharide chains of Salmonella LPS with O antigen 6,7 (Man, Glc, GlcNAc) were resistant to HF. The lability towards HF was shown to be due to the presence of the deoxysugar L-rhamnose in the saccharide backbone of the O antigen 4,5,12, since only Rha was found as the terminal sugar in the corresponding dialysable material. Hydrofluoric acid can thus be used to specifically cleave Rha-containing polysaccharides.     

Territorial behaviour of the male johnny darter,Etheostoma nigrum

Synopsis A field study was undertaken to describe the territorial behaviour of male johnny darters (Etheostoma nigrum) over the reproductive cycle. While defending eggs, males performed fewer Lateral Displays and lost fewer encounters with conspecific males than in the pre-egg phase. As the reproductive cycle progressed males were less responsive to females and performed relatively fewer courtship and more aggressive displays. Nesting males apparently shifted from a sexual to a parental phase shortly after acquiring eggs.Frequency of response, responsiveness (number of responses/number of intrusions x 100) and maximum distance of response (MDR) of male johnny darters were highest early in the reproductive cycle and decreased over the egg-guarding phase. The patterns of territorial defence exhibited by male johnny darters over the reproductive cycle were similar to those of other species of fish with paternal care.