Effects of light and regulators on senescence-related changes in soluble proteins in detached oat (Avena sativa L.) leaves

The rate of senescence and the two-dimensional pattern of soluble proteins from detached oat leaves senescing in either darkness or light were analyzed, and compared to those of leaves in which senescence was delayed by application of the cytokinin benzyladenine or enhanced through the action of abscisic acid.Senescence of detached leaves in light did not differ significantly from senescence in attached leaves on intact plants. In darkness, protein was lost at a higher rate than in light, but several individual proteins showed relative increases. Notably, proteins previously characterized as high-molecular-weight proteins and senescence-associated proteins (Klerk et al., 1992) increased. Changes observed during incubation in light or darkness appeared to be related to this condition rather than the rate or progress of senescence. Cytokinins delayed and abscisic acid accelerated the changes in protein pattern compared to water. Beside changes previously identified in leaves senescing on the plant, detached leaves show alterations that reflect their condition of incubation rather than their developmental progress.Abbreviations 2D-PAG two-dimensional polyacrylamide gel electrophoresis - ABA abscisic acid - BA N⁶-benzyladenine - BSA bovine serum albumin - EDTA ethylenediamine tetraacetic acid - IEF isoelectric focusing - Rubisco ribulosebisphosphate carboxylase/oxygenase - SDS sodium dodecyl sulfate - Tris tris (hydroxymethyl) aminomethane     

Altruistic Punishment and Between-Group Competition

Collective action, or the large-scale cooperation in the pursuit of public goods, has been suggested to have evolved through cultural group selection. Previous research suggests that the costly punishment of group members who do not contribute to public goods plays an important role in the resolution of collective action dilemmas. If large-scale cooperation sustained by the punishment of defectors has evolved through the mechanism of cultural group selection, two implications regarding costly punishment follow: (1) that people are more willing to punish defecting group members in a situation of intergroup competition than in a single-group social dilemma game and (2) that levels of "perverse" punishment of cooperators are not affected by intergroup competition. We find confirmation for these hypotheses. However, we find that the effect of intergroup competition on the punishment of defectors is fully explained by the stronger conditionality of punishment on expected punishment levels in the competition condition.     

Procedure for determining heptose and hexose in lipopolysaccharides. Modification of the cysteine-sulfuric acid method

A modification is presented of the cysteine-H₂SO₄ procedure for the quantitative assays of heptose and hexose in unhydrolyzed lipopolysaccharide of P. multocida. The modification overcomes the problems of interference and low sensitivity which we found in applying the heptose procedures of Dische and Osborn to unhydrolyzed lipopolysaccharide. We changed these procedures by (a) adding the cysteine-HCl to the reaction mixture before heating, (b) increasing the H₂SO₄ concentration in the reaction mixture, (c) extending the heating period to 20 min, and (d) reading the absorbances at 1 hr. The resulting modification, when compared with the procedures of Dische and Osborn, gave the characteristic heptose absorbance peak with an increased differential absorbance of 1.7-fold for unhydrolyzed lipopolysaccharide of P. multocida and 2.5-fold for a commercial sample of E. coli lipopolysaccharide. d-Glycero-l-mannoheptose responded linearly over a 25–100 μg range with a 1.5-fold increase in sensitivity. Heptose in mixtures with hexoses gave a linear response with a 1.8-fold increase in detection. We also obtained a 2-fold increase in the determination of the primary cysteine-H₂SO₄ product of glucose with our modification.     

Macroinvertebrates as bioindicators of water quality in the Mkondoa River,Tanzania, in an agricultural area

The suitability of using macroinvertebrates as bioindicators of stream water quality was tested in the Mkondoa River in an agricultural area at Kilosa, using the rapid bioassessment protocol. The family biotic index (FBI) showed marked variation in water quality along the stream from values ranging from 4.1 to 5.0 in the upstream reaches, indicating good water quality, 5.3 to 5.5 in the mid-reaches and 6.0 to 6.5 in the lower reaches. The water quality index (WQI) indicated that water quality was fair (77 ± 0.98) in the upstream reach of the Mkondoa, marginal (55 ± 0.86) in the midstream reach and poor (33 ± 0.45) in the downstream reach. There were significant relationships between biological oxygen demand and dissolved oxygen and the occurrence of specific taxa, mainly Chironomus and Caenis. Significant changes in macroinvertebrate abundance were mostly related to changes in water quality. As in other parts of the world, macroinvertebrate communities proved to be good biological indicators of water quality and they should be used as bioindicators in long-term monitoring of this river.     

A Randomised Controlled Trial of Consent Procedures for the Use of Residual Tissues for Medical Research: Preferences of and Implications for Patients,Research and Clinical Practice

Background

Despite much debate, there is little evidence on consequences of consent procedures for residual tissue use. Here, we investigated these consequences for the availability of residual tissue for medical research, clinical practice, and patient informedness.

Methods

We conducted a randomised clinical trial with three arms in six hospitals. Participants, patients from whom tissue had been removed for diagnosis or treatment, were randomised to one of three arms: informed consent, an opt-out procedure with active information provision (opt-out plus), and an opt-out procedure without active information provision. Participants received a questionnaire six weeks post-intervention; a subsample of respondents was interviewed. Health care providers completed a pre- and post-intervention questionnaire. We assessed percentage of residual tissue samples available for medical research, and patient and health care provider satisfaction and preference. Health care providers and outcome assessors could not be blinded.

Results

We randomised 1,319 patients, 440 in the informed consent, 434 in the opt-out plus, and 445 in the opt-out arm; respectively 60.7%, 100%, and 99.8% of patients’ tissue samples could be used for medical research. Of the questionnaire respondents (N = 224, 207, and 214 in the informed consent, opt-out plus, and opt-out arms), 71%, 69%, and 31%, respectively, indicated being (very) well informed. By questionnaire, the majority (53%) indicated a preference for informed consent, whereas by interview, most indicated a preference for opt-out plus (37%). Health care providers (N = 35) were more likely to be (very) satisfied with opt-out plus than with informed consent (p = 0.002) or opt-out (p = 0.039); the majority (66%) preferred opt-out plus.

Conclusion

We conclude that opt-out with information (opt-out plus) is the best choice to balance the consequences for medical research, patients, and clinical practice, and is therefore the most optimal consent procedure for residual tissue use in Dutch hospitals.

Trial Registration

Dutch Trial Register NTR2982     

Myosin light-chain expression during avian muscle development

Monoclonal antibodies to adult chicken myosin light chains were generated and used to quantitate the types of myosin light-chain (MLC) isoforms expressed during development of the pectoralis major (PM), anterior latissimus dorsi (ALD), and medial adductor (MA) muscles of the chicken. These are muscles which, in the adult, are composed predominantly of fast, slow, and a mixture of fiber types, respectively. Three distinct phases of MLC expression characterized the development of the PM and MA muscles. The first identifiable pase occurred during the period of 5-7 d of incubation in ovo. Extracts of muscles from the pectoral region (which included the presumptive PM muscle) contained only fast MLC isoforms. This period of exclusive fast light-chain synthesis was followed by a phase (8- 12 d of incubation in ovo) in which coexpression of both fast and slow MLC isoforms was apparent in both PM and MA muscles. During the period, the composition of both fast and slow MLC isoforms in the PM and MA muscles was identical. Beginning at day 12 in ovo, the ALD was also subjected to immunochemical analyses. The proportion of fast and slow MLCs in this muscle at day 12 was similar to that present in the other muscles studied. The third development phase of MLC expression began at approximately 12 d of incubation in ovo and encompassed the transition in MLC composition to the isoform patterns incubation in ovo and encompassed the transition in MLC composition to the isoform patterns typical of adult muscle. During this period, the relative proportion of slow MLC rose in both the MA and ALD and fell in the PM. By day 16, the third fast light chain, LC(3f), was apparent in extracts of both the PM and MA. These results show that there is a developmental progression in the expression of MLC in the two avian muscles studied from day 5 in ovo; first, only fast MLCs are accumulated, then both fast and slow MLC isoforms are expressed. Only during the latter third of development in ovo is the final MLC isoform pattern characteristic of a particular muscle type expressed.     

Isolation from Pasteurella multocida of a Lipopolysaccharide Antigen with Immunizing and Toxic Properties

A heat-stable, particulate, lipopolysaccharide-protein antigenic complex has been isolated from a virulent, encapsulated strain of Pasteurella multocida by extraction with cold, formalinized saline, and centrifugation at 105,000 x g. The original bacterial culture had been obtained from a bison that died of hemorrhagic septicemia, an infectious disease of cattle and buffalo. Injection of fractional milligram amounts of the antigen into mice, rabbits, and calves produced toxic reactions which frequently resulted in death of the host. The surviving animals demonstrated a high degree of immunity to challenge with live, virulent organisms. Two injections with 15 mug of the antigen produced a high degree of immunity in mice without the development of any signs of toxicity. The gross chemical composition and toxicity of the antigen were similar to those reported for endotoxins obtained by the Boivin or Westphal procedure. Although strong serological cross-reactions were obtained in Ouchterlony plates between the 105,000 x g antigens from the bison strain and an avian strain with antisera to these strains, these antisera agglutinated only the bacterial cells of the homologous strain. The active immunity obtained in mice by the injection of the 105,000 x g antigens of each strain was specific and could be correlated with the agglutination tests.     

Isopycnic characterization of lipopolysaccharides from Pasteurella multocida

In a novel application of an established procedure, isopycnic density gradient centrifugation procedures were used to analyze material obtained from the Westphal phenol extraction procedure of Pasteurella multocida cells. The initial phenol phase contained most of the lipopolysaccharides (LPS) and the major component had a buoyant density of 1.38 g/ml in CsCl density gradients. Repartitioning the phenol phase with an equal volume of water produced a second aqueous phase which contained most of the LPS. This LPS appeared as a single symmetrical band with a buoyant density of 1.40 g/ml. Buoyant density patterns obtained with schlieren optics in CsCl density gradients were useful in characterizing LPSs from P. multocida.     

Regulation of steady-state luteinizing hormone messenger ribonucleic acid levels, de novo synthesis, and release by sex steroids in primary pituitary cell cultures of male African catfish, Clarias gariepinus

Primary pituitary cell cultures from sexually mature adult male African catfish, Clarias gariepinus, were used to study the regulation of LH biosynthesis by sex steroids. The cell cultures were exposed to testosterone (T), estradiol (E(2)), or 5alpha-dihydrotestosterone (DHT), a nonaromatizable analogue of T, and to the likewise nonaromatizable 11-ketotestosterone (KT) and 11beta-hydroxyandrostenedione (OHA), physiologically relevant androgens in fish. Both T and E(2) elevated glycoprotein alpha (GPalpha) and LHbeta steady-state mRNA levels (quantified by RNase protection assay), de novo synthesis (metabolic incorporation of radioactive amino acids and subsequent immune precipitation of LH), and release of preferentially newly synthesized LH, while DHT had no effect. Inhibiting the aromatase activity abolished the stimulatory effects of T. The effects of E(2) on LH mRNA levels and de novo synthesis were dose dependent. Incubation with 10 ng/ml KT elevated GPalpha and LHbeta mRNA levels, while other concentrations of KT or all concentrations of OHA tested had no effect. The amount of newly synthesized LH, on the other hand, was decreased dose-dependently by OHA but not by KT. Since this OHA-induced decrease did not change the specific activity (dpm immune precipitable [(3)H]-LH/ng immune-reactive LH) of LH, we hypothesize that OHA exerted its effect by activating a crinophagic breakdown of secretory granules in catfish gonadotrophs. Electron microscopic examination of gonadotrophs after in vitro exposure to 50 ng OHA/ml revealed that breakdown organelles had increased in size significantly. We conclude that the balanced production of aromatizable (mainly stimulatory) and 11-oxygenated androgens (mainly inhibitory) may be an important factor in regulating the amounts of LH available for secretion in male African catfish.