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.     

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.     

Molecular characterization of a dechlorinating community resulting from in situ biostimulation in a trichloroethene-contaminated deep, fractured basalt aquifer and comparison to a derivative laboratory culture

Sodium lactate additions to a trichloroethene (TCE) residual source area in deep, fractured basalt at a U.S. Department of Energy site have resulted in the enrichment of the indigenous microbial community, the complete dechlorination of nearly all aqueous-phase TCE to ethene, and the continued depletion of the residual source since 1999. The bacterial and archaeal consortia in groundwater obtained from the residual source were assessed by using PCR-amplified 16S rRNA genes. A clone library of bacterial amplicons was predominated by those from members of the class Clostridia (57 of 93 clones), of which a phylotype most similar to that of the homoacetogen Acetobacterium sp. strain HAAP-1 was most abundant (32 of 93 clones). The remaining Bacteria consisted of phylotypes affiliated with Sphingobacteria, Bacteroides, Spirochaetes, Mollicutes, and Proteobacteria and candidate divisions OP11 and OP3. The two proteobacterial phylotypes were most similar to those of the known dechlorinators Trichlorobacter thiogenes and Sulfurospirillum multivorans. Although not represented by the bacterial clones generated with broad-specificity bacterial primers, a Dehalococcoides-like phylotype was identified with genus-specific primers. Only four distinct phylotypes were detected in the groundwater archaeal library, including predominantly a clone affiliated with the strictly acetoclastic methanogen Methanosaeta concilii (24 of 43 clones). A mixed culture that completely dechlorinates TCE to ethene was enriched from this groundwater, and both communities were characterized by terminal restriction fragment length polymorphism (T-RFLP). According to T-RFLP, the laboratory enrichment community was less diverse overall than the groundwater community, with 22 unique phylotypes as opposed to 43 and a higher percentage of Clostridia, including the Acetobacterium population. Bioreactor archaeal structure was very similar to that of the groundwater community, suggesting that methane is generated primarily via the acetoclastic pathway, using acetate generated by lactate fermentation and acetogenesis in both systems.     

Systems analysis of primary Sjögren's syndrome pathogenesis in salivary glands identifies shared pathways in human and a mouse model

Bone tissue has an exceptional quality to regenerate to native tissue in response to injury. However, the fracture repair process requires mechanical stability or a viable biological microenvironment or both to ensure successful healing to native tissue. An improved understanding of the molecular and cellular events that occur during bone repair and remodeling has led to the development of biologic agents that can augment the biological microenvironment and enhance bone repair. Orthobiologics, including stem cells, osteoinductive growth factors, osteoconductive matrices, and anabolic agents, are available clinically for accelerating fracture repair and treatment of compromised bone repair situations like delayed unions and nonunions. Preclinical and clinical studies using biologic agents like recombinant bone morphogenetic proteins have demonstrated an efficacy similar or better than that of autologous bone graft in acute fracture healing. A lack of standardized outcome measures for comparison of biologic agents in clinical fracture repair trials, frequent off-label use, and a limited understanding of the biological activity of these agents at the bone repair site have limited their efficacy in clinical applications.     

Detection of interspecies hybridisation in Chondrichthyes: hybrids and hybrid offspring between Australian (Carcharhinus tilstoni) and common (C. limbatus) blacktip shark found in an Australian fishery

Interspecies hybridisation in nature is a well-studied phenomenon, but it has not been analysed using genetic markers in the class Chondrichthyes (sharks, rays and chimeras). Two black-tip whaler shark species (Australian, Carcharhinus tilstoni; Common, C. limbatus) have overlapping distributions in Australia, distinct mitochondrial DNA sequence (ND4, COI, control region) and distinct morphological features such as length at sexual maturity, length at birth and number of vertebrae. A mismatch was observed between species identification using mtDNA sequence and species identification using morphological characters. To test whether hybridisation between the two species was responsible, a nuclear gene with species-specific mutations was sequenced. Extensive interspecies hybridisation was found to be occurring. Hybrids were found from five locations on the eastern Australian coastline, spanning 2,000 km. If hybrid fitness is low and hybrids are common, then fisheries recruitment may be overestimated and the productivity of the black-tip shark fishery may be well below that required to support commercial exploitation. To guard against identification errors, the likelihood of hybridisation and subsequent introgression should be assessed prior to using mtDNA (e.g. barcoding) to identify shark species. The C. limbatus–C. tilstoni species complex provides a unique opportunity to investigate the ability of sharks to adapt to environmental change, in particular, the impact of hybridization on species distributions which favour C. tilstoni along the north and C. limbatus along the south eastern Australian coastline.