The effect of glucose-6-phosphate isomerase genotype onin vitro specific activity andin vivo flux inMytilus edulis

Four samples of the musselMytilus edulis were taken between 1984 and 1987 from Stony Brook, New York, and used to study the glucose-6-phosphate isomerase (GPI) polymorphism in this species.In vitro specific activity andin vivo flux measured in the same animals were found to be significantly correlated. A significant effect of GPI genotype on flux was observed in one of the samples; overall, significant evidence of effect of genotype on enzyme activity was also obtained. GPI activities of common genotypes tend to deviate less from the population mean than those of rare (frequency less than 5%) genotypes. This suggests the possibility that rare GPI genotypes are rare as a consequence of having biochemical properties that deviate from an optimum level and, therefore, having a lower fitness. In support of this hypothesis, we found in one of our samples that shell length is a concave function of GPI activity with an intermediate optimum activity level. The financial support provided to P.J.N.S. by the Luso-American Educational Commission (Fulbright Program), the Instituto Nacional de Investigacao Científica (Portugal), and the Faculdade de Ciências da Universidade de Lisboa during several stages of this research is gratefully acknowledged. Financial support from the Ministerio de Educatión y Ciencia (Spain) in the form of a postdoctoral Fulbright/MEC fellowship to M.S. is also gratefully acknowledged. Research was supported by National Science Foundation Grant BSR-8415060 to R.K.K. This is contribution No. 736 from the Program in Ecology and Evolution, State University of New York at Stony Brook. On leave from Departamento de Biologia Vegetal, Faculdade de Ciências, Universidade de Lisboa, Campo Grande C2, Lisboa, Portugal.     

Identification of an immunodominant epitope within the phosphoprotein of rabies virus that is recognized by both class I- and class II-restricted T cells.

Immunization of H-2k mice with live rabies virus induces cytolytic T lymphocytes to the phosphoprotein of rabies virus. The antigenic determinant responsible for stimulating this class I-restricted cytolytic response was mapped to 50 amino acids (residues 180 to 229) of the phosphoprotein by using vaccinia virus recombinants expressing either the full-length phosphoprotein or C-terminal truncations of the phosphoprotein. The epitope was more finely mapped to residues 191 to 206 by using synthetic peptides. Several CD4+, class II-restricted T-cell lines were isolated from splenocytes of H-2k mice immunized with the vaccinia virus-rabies virus phosphoprotein recombinant virus. These lines were specifically stimulated by the phosphoprotein, and in addition, each line proliferated and released lymphokines in response to the same synthetic peptide shown to stimulate phosphoprotein-specific, class I-restricted cytolytic T cells.     

Distribution of sugar residues in the bovine testis during postnatal ontogenesis demonstrated with lectin-horseradish peroxidase conjugates

Summary In the present study the distribution of various sugar residues in the cells of the male gonad during postnatal organogenesis was examined employing eight lectin-horseradish peroxidase conjugates (BS-I, ConA, DBA, PNA, RCA-I, SBA, UEA-I, WGA) on paraffin-embedded testicular tissue. The tissue was obtained from bull calves and young bulls of recorded age (4, 8, 16, 20, 25, 30, 40 and 52 weeks) and two adult bulls. During the whole observation period, lectin affinity in the developing testicular tubules was restricted to the germ cell line, while the Sertoli cells and their precursors remained completely unstained. DBA, a lectin with specific affinity to -d-GalNAc, served as a selective marker for prespermatogonia (PSG), the only precursors of bovine spermatogonia until the onset of spermatogenesis at week 30. -d-GalNAc, detected in the PSG Golgi zone and its vicinity, seems to play an important role during PSG proliferation and migration in the prepuberal testis. Concomitant with the differentiation of PSG into spermatogonia, the binding intensity of DBA to the Golgi zone of these cells decreased. After the gradual onset of spermatogenesis, the lectins revealed staining of Golgi complexes of most germ cell stages. Glycosylation of the cell components takes place in the Golgi complex, which explains the strong affinity of the lectins to this cell compartment. Inner and outer membrane of the acrosomal complex of spermatids, especially during Golgi and cap phase of spermiogenesis, were intensely stained with PNA, RCA-I and SBA. This staining disappeared in the maturation phase at the latest and indicates a role of terminal d-Gal-(13)-d-GalNAc, d-Gal and d-GalNAc during the formation of the sperm head and intraepithelial orientation of the spermatid. Other parts of the spermatid, such as the anulus and the cytoplasmic droplet, exhibited d-Gal, d-GlcNAc or sialic acid and d-GalNAc. In the intertubular tissue BS-I, RCA-I and UEA-I bound to vascular endothelia. Components of the intertubular extracellular matrix were stained with ConA (-d-Man), RCA-I (d-Gal), UEA-I (-l-Fuc) and WGA (d-GlcNAc or sialic acid).     

Primary production of the periphyton in the littoral of the Danube

Summary The gross primary production of periphyton, grown on artificial substrata in the littoral of the Danube, was measured by the light and dark bottle method from April 1970 to March 1971. The periphyton used for the measurements was sampled from various depths, in order to cover the production of the whole littoral. In connection with this, the littoral area was divided into four zones limited by the heights 600 to 200 cm, according to the local water level gauge. The highest localized zone A (500–600 cm) was inundated only at maximum water levels for rather short period of time, the deepest zone D (200–300 cm) was permanently flooded.The zone A showed an average periphyton primary production of 22.5, the zone B of 54.8, the zone C of 28.9 and the zone D of 9.1 mg O₂/dm²/day. When recalculated to periods when the individual zones were inundated, the annual production was as follows: in zone A: 0.94, zone B: 9.20, zone C: 7.29 and zone D: 3.06g O₂/dm². The highest primary production was always found in the zone just below the water level. Exceptions occurred only when this zone was inundated for a short time as a result of a temporary rise of the water level and the periphyton was insufficiently developed.In order to compare the values of primary production of periphyton obtained from shallower rivers, where the whole bottom is well illuminated, or from rivers that do not exhibit such frequent and extensive level oscillations as the Danube, average value calculated from results obtained from the zone closest to the water level at the time of measurements, were always used. These results represent a special zone following the water level changes which is called surface zone. Primary periphytic production in the surface zone was 43.8 mg O₂/dm²/day. For the annual period it corresponds to the value of 14.74 g O₂/dm². Efficiently of gross photosynthesis in this zone was on the average 1.72%.The height of the water level and the water temperature were higly correlated with gross periphytic production. Close relationships between chlorophyll a concent, biomass and gross primary production of periphyton were found.

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Zusammenfassung Die Bruttoprimärproduktion des auf künstlichem Substrat im litoralen Bereich der Donau wachsenden Periphytons, wurde vom April 1970 bis zum März 1971, mit Hilfe der Hell-Dunkelflaschenmethode, gemessen. Das für die Messung herangezogene Periphyton wurde aus verschiedenen Tiefenzonen entnommen, um die Produktion der gesamten Uferzone festzuhalten. Im Zusammenhang damit wurde der litorale Bereich der Donau in 4 Zonen gegliedert, welche ihre Grenzen bei einem Pegelstand von 600–200 cm des Ortspegels hatten. Die höchste Zone A (500–600 cm) wurde nur bei den höchsten Wasserstanden und nur für kurze Zeit vom Wasser überflutet, die tiefste Zone D (200–300 cm) war dauernd unter Wasser.In der Zone A war die durchschnittliche Produktion des Periphytons 22,5 mg O₂/dm²/Tag, in Zone B 54,8 mg, in Zone C 28,9 mg und in Zone D 9.1 mg. Nach Berechnung für die Zeit, in der die einzelnen Zonen vom Wasser bedeckt waren war folgende Produktion in den einzelnen Zonen festzustellen: in Zone A 0,94 g O₂/dm², in Zone B 9,20 g, in Zone C 7,29 g und in Zone D 3,06 g. Die höchste Periphytonproduktion wurde jeweils in der Zone festgestellt, welche dem Wasserspiegel am nächsten war. Eine Ausnahme bildeten nur jene Fälle, in denen these Zone nach vorübergehender Erhöhung des Wasserspiegels erst kurze Zeit vom Wasser bedeckt war und das Periphyton ungenügend entwickelt war.Zum Vergleich mit den Werten der Primärproduktion des Aufwuchses aus seichteren Gewässern mit gut belichteter Sohle, oder aus Flüssen welche nicht so häufige und weitreichende Spiegelschwankungen aufweisen wie die Donau, wird in der vorgelegten Arbeit der Durchschnittswert aus den Ergebnissen der Zone verwendet, welche zur Zeit der Messungen dem Wasserspiegel am nächsten war. Diese Ergebnisse repräsentieren eine besondere Zone, welche den Schwankungen des Wasserspiegels folgt und von den Autoren durch den Begriff Oberflachenzone bezeichnet wird. Die Primärproduktion des Periphytons in dieser Oberflächenzone war 43,8 mg O₂/dm²/Tag. Dem entspricht im Jahresverlauf ein Wert von 14,74 g O₂/dm². Die Ausnützung der Sonnenenergie war in dieser Zone im Durchschnitt 1,72%.Von den Umweltfaktoren zeigt die Höhe des Wasserspiegels und die Wassertemperatur den engsten Zusammenhang mit der Höhe der Bruttoprimärproduktion des Periphytons. In kürzeren Zeitabschnitten, in denen es zu keinen raschen ausgeprägten Schwankungen des Wasserspiegels des Flusses kommt, wurde eine enge Abhängigkeit zwischen den Werten der Primärproduktion und dem a-Chlorophylgehalt und auch der Biomasse festgestellt.

     

Work capacity during 30 days of bed rest with isotonic and isokinetic exercise training

The purpose was to test the hypothesis that twice daily, short-term, variable intensity isotonic and intermittent high-intensity isokinetic leg exercise would maintain peak O2 uptake (VO2) and muscular strength and endurance, respectively, at or near ambulatory control levels during 30 days of -6 degrees head-down bed rest (BR) deconditioning. Nineteen men (aged 32-42 yr) were divided into no exercise control (peak VO2 once/wk, n = 5), isokinetic (Lido ergometer, n = 7), and isotonic (Quinton ergometer, n = 7) groups. Exercise training was conducted in the supine position for two 30-min periods/day for 5 days/wk. Isotonic training was at 60-90% of peak VO2, and isokinetic training (knee flexion-extension) was at 100 degrees/s. Mean (+/- SE) changes (P less than 0.05) in peak VO2 (ml.m-1.kg-1) from ambulatory control to BR day 28 were 44 +/- 4 to 36 +/- 3, -18.2% (3.27-2.60 l/m) for no exercise, 39 +/- 4 to 40 +/- 3, +2.6% (3.13-3.14 l/min) for isotonic, and 44 +/- 3 to 40 +/- 2, -9.1% (3.24-2.90 l/min) for isokinetic. There were no significant changes in any groups in leg peak torque (right knee flexion or extension), leg mean total work, arm total peak torque, or arm mean total work. Mean energy costs for the isotonic and isokinetic exercise training were 446 kcal/h (18.8 +/- 1.6 ml.min-1.kg-1) and 214 kcal/h (8.9 +/- 0.5 ml.m-1.kg-1), respectively. Thus near-peak, variable intensity, isotonic leg exercise maintains peak VO2 during 30 days of BR, while this peak, intermittent, isokinetic leg exercise protocol does not.     

Induction of rabies virus-specific T-helper cells by synthetic peptides that carry dominant T-helper cell epitopes of the viral ribonucleoprotein.

The T-helper cell response to the internal proteins of rabies virus was investigated. The rabies virus nucleoprotein was shown to be a major target antigen for T-helper cells that cross-react between rabies and rabies-related viruses. T-helper cells were assayed in vitro by testing virus-induced lymphocytes for lymphokine secretion in response to antigen. Immunodominant T-helper cell epitopes of the viral nucleoprotein were identified in vitro by using synthetic peptides delineated from the amino acid sequence of the nucleoprotein. The response to synthetic peptides were under Ir gene control. Antigenic peptides were tested in vivo for stimulation of rabies virus-specific T-helper cells. Inoculation of mice with peptides bearing immunodominant T-helper cell epitopes resulted in an accelerated and enhanced neutralizing antibody response upon booster immunization with inactivated rabies virus.     

Adoptive transfer of delayed-type hypersensitivity to Sendai virus. III. Effect of H-2 mutations on recognition by K, D-region restricted T effector lymphocytes

The H-2 restriction pattern of cytolytic T lymphocytes (Tc) and T lymphocytes which mediate a delayed-type hypersensitivity response (Td) directed against infectious Sendai virus was investigated using H-2 mutant mice. Td and Tc lymphocytes exhibit the same fine specificity for self-recognition, for example, B6.C-H-2bm1 effector T cells were unable to recognize viral antigens in association with wild-type Kb and vice versa, B6.H-2bm6 effector cells did not mediate a reaction against virus plus wild-type Kb but, on the other hand, T cells of wild-type Kb recognized virus plus Kbm6 BALB/c-H-2dm2 T cells lacked reactivity against virus in association with wild-type Dd, but again wild-type Dd effector cells recognized virus plus Ddm2.     

Virus-specific T-cell sensitization

Syngeneic, semiallogeneic, or allogeneic spleen lymphocytes were transferred intonu/nu BALB/c mice, which were infected with vaccinia virus. Specific Sensitization of transferred thymus-derived cells was determined in vivo by mean survival time and virus titer in the spleen six days after infection, and in vitro by cell-mediated cytolysis of vaccinia virus-infected syngeneic target cells. Virus-specific Sensitization took place only after transfer of syngeneic or semiallogeneic spleen lymphocytes; allogeneic lymphocytes had no influence on mean survival time or virus titer and showed no virus-specific cytolytic activity in vitro. Infection of mice with vaccinia virus-strain WR, Elstree, DIs, or DIs-infected syngeneic fibroblasts resulted in the generation of virus-specific effector cells, while injection of a high amount of inactivated virus particles caused no Sensitization. These results suggest H-2 homology for production of virus-specific effector cells. Propagation of virus is not necessary, since early surface antigens, combined with syngeneic H-2 antigens, suffice for Sensitization of cytolytic T lymphocytes.Abbreviations used in this paper are as follows CMC cell-mediated cytolysis - CTL cytolytic T lymphocyte - LCM lymphocytic choriomeningitis - MHC major histocompatibility complex - MST mean survival time - T cell thymus-derived cell - TCID₅₀ 50 percent tissue culture infective dose     

Über die Silbernitrat-Reduktion der Plastiden

Ohne Zusammenfassung     

Application of an optimized marker amplification protocol in immunohistochemistry — a valuable tool for visualizing antigenic sites of low signal strength or sparse distribution

Amplification of immunohistochemical markers received considerable attention during the 1980s and 1990s. The amplification approach was largely abandoned following the development of antigen retrieval and reporter amplification techniques, because the latter were incorporated more easily into high throughput automated procedures in industrial and diagnostic laboratories. There remain, however, a number of instances where marker amplification still has much to offer. Consequently, we examined experimentally the utility of an optimized marker amplification technique in diagnostically relevant tissue where either the original signal strength was low or positive sites were visible, but sparsely distributed. Marker amplification in the former case not only improved the visibility of existing positive sites, but also revealed additional sites that previously were undetectable. In the latter case, positive sites were rendered more intense and therefore more easily seen during low magnification examination of large areas of tissue.