Physiological consequences of an altered flow regime on Alabama bass (Micropterus henshalli)

There are numerous studies on the effects of dams on aquatic biota, yet relatively little is known about whether hydropeaking activities cause physiological change in fish. Using Alabama bass (Micropterus henshalli) as a model, we evaluated whether hydropeaking in a regulated river altered glucocorticoid stress responsiveness relative to fish from an unregulated tributary. Blood samples were collected at the time of capture (baseline) and then collected again after a 1‐hr period of confinement (response). Leukocyte profiles (blood smears) were created and plasma was extracted to assess plasma cortisol levels and neutrophils and lymphocyte (N:L) ratios, between sites and times to evaluate differences between sites and the two sampling periods. Baseline cortisol levels were higher in fish collected from the regulated river compared to those from unregulated site, but response levels of cortisol were similar between sites. Baseline and response level N:L ratios did not differ between sites. High baseline levels of cortisol suggested that fish exposed to regulated flows expressed an altered stress response and were likely in an allostatic state, i.e., attempting to acclimate. Further research is needed to understand how altered stress responses due to hydropeaking flows may be affecting fish.     

Australia Antigen and Liver Function Tests Following Infectious Hepatitis—A Study of 111 Patients in Quest of Aids in Blood Donor Screening

An epidemic of infectious hepatitis involving 99 patients and employees of a state mental hospital revealed Australia antigen Au(1) to be absent from the blood of all but one of the subjects when tested at six weeks, three months, nine months and 12 to 18 months after onset of jaundice. The single patient with Au(1) at 12 months had no enzyme abnormality to indicate residual liver disease.If Au(1) is the virus of hepatitis these data would support the concept that persistent or long standing viremia is not a feature of epidemic hepatitis. Moreover, results of this study suggest that the Au(1) test should not be used to establish the absence of a past history of hepatitis in blood donors. These data do not establish the value of the Au(1) test in blood donors with active viremia, but do suggest that of 111 patients with recent hepatitis 1 percent had persistent antigenemia and 4 percent probably had circulating antigen antibody complexes and constituted a potential risk to recipients of their blood. The degree of risk to recipients from transfused blood of post-hepatitis patients without demonstrable Au(1) cannot be assessed.     

United in adversity: Aridity and cold influence aggregation behaviour in a social lizard,Egernia stokesii

Sociality has evolved independently many times in a diverse array of animal taxa. While sociality in some invertebrates, birds and mammals is relatively well understood, complex social behaviour in Squamate reptiles is a comparatively recent discovery. The extent to which social behaviour is phylogenetically constrained, or free to respond to environmental conditions is a key question in understanding sociality. We sampled 74 aggregations involving 137 individuals of a social lizard (Egernia stokesii) from 13 sites across a 96 250 km² area showing a wide range of environmental conditions. Over all locations, 70% of the lizards were found in aggregations, supporting the previous suggestion that aggregation in this species is phylogenetically constrained. However, the size of aggregations was negatively related to spatial variation in aridity and daily variation in maximum temperature, suggesting that social behaviour also varied in response to harsh environmental conditions. Lizards aggregated more in arid areas and on cold days. Our results show that it is overly simplistic to regard social behaviour in E. stokesii as either phylogenetically constrained or environmentally determined. A more nuanced appreciation of the extent to which social behaviour is free to vary in response to environmental conditions improves our understanding of social behaviour in Squamate reptiles.     

An attenuating mutation in nsP1 of the Sindbis-group virus S.A.AR86 accelerates nonstructural protein processing and up-regulates viral 26S RNA synthesis

The Sindbis-group alphavirus S.A.AR86 encodes a threonine at nonstructural protein 1 (nsP1) 538 that is associated with neurovirulence in adult mice. Mutation of the nsP1 538 Thr to the consensus Ile found in nonneurovirulent Sindbis-group alphaviruses attenuates S.A.AR86 for adult mouse neurovirulence, while introduction of Thr at position 538 in a nonneurovirulent Sindbis virus background confers increased neurovirulence (M. T. Heise et al., J. Virol. 74:4207-4213, 2000). Since changes in the viral nonstructural region are likely to affect viral replication, studies were performed to evaluate the effect of Thr or Ile at nsP1 538 on viral growth, nonstructural protein processing, and RNA synthesis. Multistep growth curves in Neuro2A and BHK-21 cells revealed that the attenuated s51 (nsP1 538 Ile) virus had a slight, but reproducible growth advantage over the wild-type s55 (nsP1 538 Thr) virus. nsP1 538 lies within the cleavage recognition domain between nsP1 and nsP2, and the presence of the attenuating Ile at nsP1 538 accelerated the processing of S.A.AR86 nonstructural proteins both in vitro and in infected cells. Since nonstructural protein processing is known to regulate alphavirus RNA synthesis, experiments were performed to evaluate the effect of Ile or Thr at nsP1 538 on viral RNA synthesis. A combination of S.A.AR86-derived reporter assays and RNase protection assays determined that the presence of Ile at nsP1 538 led to earlier expression from the viral 26S promoter without affecting viral minus- or plus-strand synthesis. These results suggest that slower nonstructural protein processing and delayed 26S RNA synthesis in wild-type S.A.AR86 infections may contribute to the adult mouse neurovirulence phenotype of S.A.AR86.     

Phylogenetics of Lophodermium from pine

Lophodermium comprises ascomycetous fungi that are both needle-cast pathogens and asymptomatic endophytes on a diversity of plant hosts. It is distinguished from other genera in the family Rhytismataceae by its filiform ascospores and ascocarps that open by a longitudinal slit. Nucleotide sequences of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA were used to infer phylogenetic relationships within Lophodermium. Twenty-nine sequences from approximately 11 species of Lophodermium were analyzed together with eight sequences from isolates thought to represent six other genera of Rhytismataceae: Elytroderma, Lirula, Meloderma, Terriera, Tryblidiopsis and Colpoma. Two putative Meloderma desmazieresii isolates occurred within the Lophodermium clade but separate from one another, one grouped with L. indianum and the other with L. nitens. An isolate of Elytroderma deformans also occurred within the Lophodermium clade but on a solitary branch. The occurrence of these genera within the Lophodermium clade might be due to problems in generic concepts in Rhytismataceae, such as emphasis on spore morphology to delimit genera, to difficulty of isolating Rhytismataceae needle pathogens from material that also is colonized by Lophodermium or to a combination of both factors. We also evaluated the congruence of host distribution and several morphological characters on the ITS phylogeny. Lophodermium species from pine hosts formed a monophyletic sister group to Lophodermium species from more distant hosts from the southern hemisphere, but not to L. piceae from Picea. The ITS topology indicated that Lophodermium does not show strict cospeciation with pines at deeper branches, although several closely related isolates have closely related hosts. Pathogenic species occupy derived positions in the pine clade, suggesting that pathogenicity has evolved from endophytism. A new combination is proposed, Terriera minor (Tehon) P.R. Johnst.     

Influenza-Specific Antibody-Dependent Phagocytosis

BackgroundImmunity to human influenza A virus (IAV) infection is only partially understood. Broadly non-neutralizing antibodies may assist in reducing disease but have not been well characterized.MethodsWe measured internalization of opsonized, influenza protein-coated fluorescent beads and live IAV into a monocytic cell line to study antibody-dependent phagocytosis (ADP) against multiple influenza hemagglutinin (HA) subtypes. We analyzed influenza HA-specific ADP in healthy human donors, in preparations of intravenous immunoglobulin (IVIG), and following IAV infection of humans and macaques.ResultsWe found that both sera from healthy adults and IVIG preparations had broad ADP to multiple seasonal HA proteins and weak cross-reactive ADP to non-circulating HA proteins. The ADP in experimentally influenza-infected macaque plasma and naturally influenza-infected human sera mediated phagocytosis of both homologous and heterologous IAVs. Further, the IAV phagocytosed in an antibody-mediated manner had reduced infectivity in vitro.ConclusionWe conclude that IAV infections in humans and macaques leads to the development of influenza-specific ADP that can clear IAV infection in vitro. Repeated exposure of humans to multiple IAV infections likely leads to the development of ADP that is cross-reactive to strains not previously encountered. Further analyses of the protective capacity of broadly reactive influenza-specific ADP is warranted.     

The electronic structure of Fe2+ in reaction centers from Rhodopseudomonas sphaeroides. I. Static magnetization measurements.

We have measured the static magnetization of unreduced and reduced reaction centers that vary in their quinone content. Measurements were performed in the temperature range 0.7 degrees K less than T less than 200 degrees K and magnetic fields of up to 10 kG. The electronic g-value, crystal field parameters D, E, and the exchange interaction, J, between the quinone spin and Fe2+ were determined using the spin Hamiltonian formalism. The effective moment mu eff/Fe2+ of both reduced and unreduced samples were determined to be 5.35 +/- 0.15 Bohr magnetons. This shows, in agreement with previous findings, that Fe2+ does not change its valence state when the reaction centers are reduced. Typical values of D congruent to +5 cm-1 and E/D congruent to 0.27 are consistent with Fe being in an octahedral environment with rhombic distortion. The values of D and E were approximately the same for reaction centers having one and two quinones. These findings imply that quinone is most likely not a ligand of Fe. The Fe2+ and the spin on the quinone in reduced reaction centers were found to be coupled with an exchange interaction 0 less than /J/ less than 1 cm-1. The validity of the spin Hamiltonian was checked by using an orbital Hamiltonian to calculate energy levels of the 25 states of the S = 2, L = 2 manifold and comparing the magnetization of the lowest five states with those obtained from the spin Hamiltonian. Using the orbital Hamiltonian, we calculated the position of the first excited quintet state to be 340 cm-1 above the ground state quintet. This is in good agreement with the temperature dependence of the quadrupole splitting as determined by Mossbauer spectroscopy.