Biology,boundaries and borders

Towards Justice and Peace is a splendid title for a symposium and book to honour Professor Sunderland. It is also a very difficult title for a biological anthropologist. I make the distinction from social anthropology with some apology. There are of course many subdisciplines and traditions within Anthropology and I most associate Professor Sunderland's support of my university and myself with our attempts to foster cross-disciplinary discussion, towards a “Biosocial Anthropology”, as it were. So, while for specialists in fossilization of bones, sequences of DNA molecules or analysis of urine, the title, Towards Justice and Peace might cause problems, I should like to discuss some biosocial anthropology on an international frontier, which, after centuries of military aggression and defence, is now a peaceful line on a map within the European Community. HMM.     

Extracellular enzymes of some additional fungi associated with mushroom culture

Twenty-four fungus isolates from the compost utilized in commercially growing Agaricus brunnescens were tested for their ability to produce extracellular enzymes involved in the degradation of cellulose, lignin and xylan, the major components of the straw of the compost. All 24 isolates were able to degrade carboxymethyl cellulose. Most were classified as weak or moderate producers of exo--glucanase. Twenty of the 24 were also able to hydrolyze filter paper, a crystalline cellulose. Nineteen of the 24 were able to hydrolyze xylan, a hemicellulose. The production of extracellular polyphenol oxidases was detected utilizing two tests; the blueing of alcoholic gum guaiacol, which indicates tyrosinase production, and the browning of malt extract-gallic acid agar, which indicates laccase production. Twenty produced tyrosinase, but only eight produced laccase. Agaricus brunnescens was also included in all of the tests. It produced exo--glucanase, hemicellulase, tyrosinase and lactase.     

Physicochemical properties of dipalmitoyl phosphatidylcholine after interaction with an apolipoprotein of pulmonary surfactant

We studied the interaction between an apolipoprotein of pulmonary surfactant and the principal lipid found in this material, dipalmitoyl phosphatidylcholine. The apolipoprotein was extracted from canine surfactant and purified to greater than 90% homogeneity. The apolipoprotein was mixed for 16 h at room temperature with dipalmitoyl phosphatidylcholine dispersed in a buffer containing 0.1 M NaCl and 3mM CaCl2. Unbound lipid, unbound protein, and recombinants of lipid and protein were separated by density gradient centrifugation. 71% of the apolipoprotein was found associated with dipalmitoyl phosphatidylcholine. In comparable experiments using bovine plasma albumin about 13% of the albumin was recovered with the lipid. The physicochemical state of the lipid in the apolipoprotein-lipid complex was modified after binding of the protein. A distinct phase transition at 42 degrees C could no longer be detected, and the rate of adsorption to an air-liquid interface of the apolipoprotein-lipid complex was greater than that of the lipid alone. Surface tension vs. surface area isotherms of the dipalmitoyl phosphatidylcholine-apolipoprotein materials, however, were similar to those exhibited by pure dipalmitoyl phosphatidylcholine. The results suggest a physiological role for this apolipoprotein. It may bind to dipalmitoyl phosphatidylcholine under conditions expected in vivo, and may modify the physical properties of the aggregated dipalmitoyl phosphatidylcholine to form domains of lipid in a liquid-crystalline array. The complex dipalmitoyl phosphatidylcholine and apolipoprotein would have the physical properties necessary for its physiological function, allowing it to absorb to the alveolar interface and reduce its surface tension to less than 10 dynes/cm. Dipalmitoyl phosphatidylcholine, by itself, is in a gel-crystalline array below its phase transition temperature (42 degrees C) and would be incapable of effecting these actions.     

Hybridisation,paternal leakage and mitochondrial DNA linearization in three anomalous fish (Scombridae)

Using mitochondrial DNA for species identification and population studies assumes that the genome is maternally inherited, circular, located in the cytoplasm and lacks recombination. This study explores the mitochondrial genomes of three anomalous mackerel. Complete mitochondrial genome sequencing plus nuclear microsatellite genotyping of these fish identified them as Scomberomorus munroi (spotted mackerel). Unlike normal S. munroi, these three fish also contained different linear, mitochondrial genomes of Scomberomorus semifasciatus (grey mackerel). The results are best explained by hybridisation, paternal leakage and mitochondrial DNA linearization. This unusual observation may provide an explanation for mtDNA outliers in animal population studies.     

A comparison of the strength of biodiversity effects across multiple functions

In order to predict which ecosystem functions are most at risk from biodiversity loss, meta-analyses have generalised results from biodiversity experiments over different sites and ecosystem types. In contrast, comparing the strength of biodiversity effects across a large number of ecosystem processes measured in a single experiment permits more direct comparisons. Here, we present an analysis of 418 separate measures of 38 ecosystem processes. Overall, 45 % of processes were significantly affected by plant species richness, suggesting that, while diversity affects a large number of processes not all respond to biodiversity. We therefore compared the strength of plant diversity effects between different categories of ecosystem processes, grouping processes according to the year of measurement, their biogeochemical cycle, trophic level and compartment (above- or belowground) and according to whether they were measures of biodiversity or other ecosystem processes, biotic or abiotic and static or dynamic. Overall, and for several individual processes, we found that biodiversity effects became stronger over time. Measures of the carbon cycle were also affected more strongly by plant species richness than were the measures associated with the nitrogen cycle. Further, we found greater plant species richness effects on measures of biodiversity than on other processes. The differential effects of plant diversity on the various types of ecosystem processes indicate that future research and political effort should shift from a general debate about whether biodiversity loss impairs ecosystem functions to focussing on the specific functions of interest and ways to preserve them individually or in combination.