High titres of antibody to murine leukaemia virus in lymphocyte (Ly) alloantisera

The radioimmune precipitation (RIP) assay was used to examine the antibody titres against endogenous AKR murine leukaemia virus (MuLV) in a number of antisera to lymphocyte (Ly) alloantigens. The sera from normal donor and unimmunized recipient mice used in raising the alloantisera were also examined for anti-MuLV activity. It was found that all the antisera had high anti-MuLV titres and that in all but one case alloantigen immunization augmented the anti-viral titres. The degree of augmentation did not appear to be related to the anti-MuLV titre in the donor strain sera. Three I-region antisera were also examined for anti-MuLV antibodies and were found to have lower anti-viral titres than the Ly antisera even though immunization to I-region products greatly augmented the anti-viral titre. These results caution against the use of Ly antisera in characterizing the phenotype of lymphoid tumour cells without prior virus absorption.     

Hip joint replacement surgery for idiopathic osteoarthritis aggregates in families

In order to determine whether there is a genetic component to hip or knee joint failure due to idiopathic osteoarthritis (OA), we invited patients (probands) undergoing hip or knee arthroplasty for management of idiopathic OA to provide detailed family histories regarding the prevalence of idiopathic OA requiring joint replacement in their siblings. We also invited their spouses to provide detailed family histories about their siblings to serve as a control group. In the probands, we confirmed the diagnosis of idiopathic OA using American College of Rheumatology criteria. The cohorts included the siblings of 635 probands undergoing total hip replacement, the siblings of 486 probands undergoing total knee replacement, and the siblings of 787 spouses. We compared the prevalence of arthroplasty for idiopathic OA among the siblings of the probands with that among the siblings of the spouses, and we used logistic regression to identify independent risk factors for hip and knee arthroplasty in the siblings. Familial aggregation for hip arthroplasty, but not for knee arthroplasty, was observed after controlling for age and sex, suggesting a genetic contribution to end-stage hip OA but not to end-stage knee OA. We conclude that attempts to identify genes that predispose to idiopathic OA resulting in joint failure are more likely to be successful in patients with hip OA than in those with knee OA.     

Spinal curvature associated with Myxobolus sp. cysts in the brain of sand-flathead (Platycephalus bassensis L.)

We describe spinal curvature in sand-flathead, presumably due to cerebral myxoboliasis.

Résumé

Torsions de la colonne vertébrale associées aux cystes de Myxobolus sp. duns le cervean de Platycephalus bassensis L.
Des torsions de la colonne vertébrale chez Platycephalus bassensis L., probablement dûes sà une myxoboliasis cerébrale, sont décrites.

Zusammenfassung

Verkrümmungen der Wirbelsäule durch System von Myxobolus sp. im Gehirn des Sandflachkopfes ( Platycephalus bassensis L. )
Verkrümmungen der Wirbelsäule werden bei Platycephalus bassensis beschrieben und mit der cerebralen Myxoboliasis in Zusammenhang gebracht.     

Environmental controls on daytime net community calcification on a Red Sea reef flat

Coral growth and carbonate accumulation form the foundation of the coral reef ecosystem. Changes in environmental conditions due to coastal development, climate change, and ocean acidification may pose a threat to net carbonate production in the near future. Controlled laboratory studies demonstrate that calcification by corals and coralline algae is sensitive to changes in aragonite saturation state (Ω_a), as well as temperature, light, and nutrition. Studies also show that the dissolution rate of carbonate substrates is impacted by changes in carbonate chemistry. The sensitivity of coral reefs to these parameters must be confirmed and quantified in the natural environment in order to predict how coral reefs will respond to local and global changes, particularly ocean acidification. We estimated the daytime hourly net community metabolic rates, both net community calcification (NCC) and net community productivity (NCP), at Sheltered Reef, an offshore platform reef in the central Red Sea. Average NCC was 8 ± 3 mmol m⁻² h⁻¹ in December 2010 and 11 ± 1 mmol m⁻² h⁻¹ in May 2011, and NCP was 21 ± 7 mmol m⁻² h⁻¹ in December 2010 and 44 ± 4 mmol m⁻² h⁻¹ in May 2011. We also monitored a suite of physical and chemical properties to help relate the rates at Sheltered Reef to published rates from other sites. While previous research shows that short-term field studies investigating the NCC–Ω_a relationship have differing results due to confounding factors, it is important to continue estimating NCC in different places, seasons, and years, in order to monitor changes in NCC versus Ω in space and time, and to ultimately resolve a broader understanding of this relationship.

     

Pine invasions in treeless environments: dispersal overruns microsite heterogeneity

Understanding biological invasions patterns and mechanisms is highly needed for forecasting and managing these processes and their negative impacts. At small scales, ecological processes driving plant invasions are expected to produce a spatially explicit pattern driven by propagule pressure and local ground heterogeneity. Our aim was to determine the interplay between the intensity of seed rain, using distance to a mature plantation as a proxy, and microsite heterogeneity in the spreading of Pinus contorta in the treeless Patagonian steppe. Three one‐hectare plots were located under different degrees of P. contorta invasion (Coyhaique Alto, 45° 30′S and 71° 42′W). We fitted three types of inhomogeneous Poisson models to each pine plot in an attempt for describing the observed pattern as accurately as possible: the “dispersal” models, “local ground heterogeneity” models, and “combined” models, using both types of covariates. To include the temporal axis in the invasion process, we analyzed both the pattern of young and old recruits and also of all recruits together. As hypothesized, the spatial patterns of recruited pines showed coarse scale heterogeneity. Early pine invasion spatial patterns in our Patagonian steppe site is not different from expectations of inhomogeneous Poisson processes taking into consideration a linear and negative dependency of pine recruit intensity on the distance to afforestations. Models including ground‐cover predictors were able to describe the point pattern process only in a couple of cases but never better than dispersal models. This finding concurs with the idea that early invasions depend more on seed pressure than on the biotic and abiotic relationships seed and seedlings establish at the microsite scale. Our results show that without a timely and active management, P. contorta will invade the Patagonian steppe independently of the local ground‐cover conditions.     

Composite autologous-allogeneic skin replacement: development and clinical application

A major unsolved problem in skin restoration in severe burns is replacement of lost dermis. We report the development and clinical application of a composite grafting technique in which allogeneic skin is the source of dermis, and cultured autologous keratinocytes generate epidermis. Excised burn wounds are resurfaced with unmatched allograft. Immunosuppression from the burn and reduced immunoreactivity of the allograft permit successful allograft engraftment. Keratinocyte cultures are initiated from the patient. Allogeneic epidermis is removed, and the dermal bed is resurfaced with keratinocyte cultures. The allogeneic dermis promotes rapid (less than 7 days) stratification, maturation, and integration of the cultures and the synthesis of anchoring fibrils. One case followed 11 months has shown no evidence of rejection. We reason that removal of the epidermis from allograft eliminates the majority of cells constitutively expressing alloclass II antigens, leaving behind a viable allogeneic dermal bed that serves as an ideal substrate for engraftment and integration of keratinocyte cultures but does not initiate rejection.     

On the causes of interspecific differences in the growth-irradiance relationship for phytoplankton. Part I. A comparative study of the growth-irradiance relationship of three marine phytoplankton species: Skeletonema costatum, Olisthodiscus luteus and Gonyaulax tamarensis

Three marine phytoplankton species (Skeletonema costatum, Olisthodiscusluteus andGonyaulax tamarensis) were grown in batch culturesat 15°C and a 14:10 L:D cycle at irradiance levels rangingfrom 5 to 450 µEinst m^–2 s^–1. At each irradiance,during exponential growth, concurrent measurements were madeof cell division, carbon-specific growth rate, photosyntheticperformance (both O₂ and POC production), dark respiration,and cellular composition in terms of C, N and chlorophyll a.The results indicate that the three species were similar withrespect to chemical composition, C:N (atomic) = 6.9 ±0.4, photo-synthetic quotient, 1.43 ± 0.09, and photosyntheticefficiency, 2.3 ±0.1 x 10^–3 µmol O₂ (µgChl a)^–1 h^–1 (µEinst m^–2 s^–1)^–1.Differences in maximum growth rate varied as the –0.24power of cell carbon. Differences in growth efficiency, werebest explained by a power function of Chl a:C at µ = 0.Compensation intensities, ranged from 1.1 µEinst m^–2s^–1 for S. costatum to 35 forG. tamarensis and were foundto be a linear function of the maintenance respiration rate.The results indicate that interspecific differences in the µ–Irelationship can be adequately explained in terms of just threeparameters: cell carbon at maximum growth rate, the C:Chl aratio (at the limit as growth approaches zero) and the respirationrate at zero growth rate. A light-limited algal growth modelbased on these results gave an excellent fit to the experimentalµ–I curves and explained 97% of the observed interspecificvariability. ¹Present address: Lamont-Doherty Geological Observatory Columbiaof University, Palisades, NY 10964, USA     

Immunological evidence that band 3 is the major glucose transporter of the human erythrocyte membrane

We have previously reported that human erythrocyte band 3 contains 90-95% of the reconstitutable glucose transport activity of the erythrocyte membrane (Shelton, R.L. and Langdon, R.G. (1983) Biochim. Biophys. Acta 733, 25-33). We have now found that monoclonal and polyclonal antibodies to epitopes on band 3 specifically removed band 3 and more than 90% of the reconstitutable glucose transport activity from unfractionated octylglucoside extracts of erythrocyte membranes; nonimmune serum removed neither. Western blots of whole membrane extracts revealed that the polyclonal antibody to band 4.5 used to isolate cDNA clones presumed to code for the transporter (Mueckler, M., Caruso, C., Baldwin, C.A., Pancio, M., Blench, J., Morris, H.B., Allard, W.J., Lienhard, G.E. and Lodish, H.F. (1985) Science 229, 941-945) reacts strongly with six discrete bands in the 4.5 region. A monoclonal antibody to band 3 also reacts with a Mr 55,000 component of band 4.5. We conclude that band 3 contains the major glucose transporter of human erythrocytes, and that the transport activity in band 4.5 might be attributable to a band 3 fragment. Band 3 is probably a multifunctional transport protein responsible for transport of glucose, anions, and water.     

Studies of esterase 6 in Drosophila melanogaster. XVIII. Biochemical differences between the slow and fast allozymes

Most natural populations of Drosophila melanogaster are polymorphic for two major electrophoretic variants at the esterase-6 locus. The frequency of the EST 6F allozyme is greatest in populations in warmer latitudes, whereas the EST 6S allozyme is predominant in colder latitudes. Latitudinal clines in electromorph frequencies are found on three continents. Purified preparations of the allozymes have been characterized for their pH optimum, substrate specificity, organophosphate inhibition, alcohol activation, thermal stability, and kinetic parameters. These and previous analyses of the EST 6 allozymes reveal that the two variants have differences in their physical and kinetic properties that may provide a basis for the selective maintenance of the polymorphisms and an explanation of the clinal variation observed in natural populations.