Laboratory technicians; the Clinical Laboratory Law and its meaning to private physicians

The present laws and regulations relating to clinical laboratories in California are the outcome of over a quarter century of cooperative development. The medical profession, public health department, laboratory workers, and the legislature have worked together in this development.At first the system of certifying technicians and laboratories was on a voluntary basis. The clinical laboratory law in effect legalized and made generally applicable a system which had already been accepted voluntarily. The application of the clinical laboratory law provides physicians a reasonable assurance that competence and reliability will prevail in clinical laboratory operation. Of great importance is the conduct of proper training programs by approved laboratories. Since modern medical practice is so dependent on accurate clinical laboratory work it is essential that special effort be directed by physicians toward influencing young people to enter the profession of medical technology.     

To go or not to go with the flow: Environmental influences on whale shark movement patterns

Seven whale sharks were tracked using satellite-linked tags from Ningaloo Reef, off northern Western Australia, following tagging in April and June 2002 and April-May 2005. We investigated how the movements of those whale shark tracks were influenced by geostrophic surface currents during sequential one-week periods by using a passive diffusion model parameterised with observed starting locations of the sharks and weekly maps of surface current velocity and direction (derived from altimetry). We compared the outputs from the passive diffusion model and maps of chlorophyll-a concentration (SeaWiFs/MODIS) and with the actual tracks of the sharks using GIS and generalized linear mixed-effects models (GLMM). The GLMM indicated very little support for passive diffusion with sea-surface ocean currents influencing whale shark distributions in the north eastern Indian Ocean. Moreover, the sharks' movements correlated only weakly with the spatial distribution of sea-surface chlorophyll-a concentrations. The seven whale sharks had average swimming speeds comparable with those recorded in other satellite tracking studies of this species. Swimming speeds of the seven sharks were similar to those reported in previous studies and up to three times greater than the maximum sea-surface current velocities that the sharks encountered while traversing into lower southerly latitudes (moving northward towards the equator). Our results indicate that whale sharks departing from Ningaloo travel actively and independently of near-surface currents where they spend most of their time despite additional metabolic costs of this behaviour.     

Using social networks to deduce whether residents or dispersers spread parasites in a lizard population

1. Heterogeneity of host behaviour can play an important role in the spread of parasites and pathogens around wildlife populations. Social networks have previously been suggested to represent transmission pathways within a population, but where the dynamics of host-parasite interactions are difficult to observe, networks may also be used to provide insights into transmission processes. 2. Pygmy bluetongue lizards, Tiliqua adelaidensis, occupy individual territories, live exclusively in burrows constructed by spiders in Australian native grasslands and are hosts to a tick, Bothriocroton hydrosauri, and a nematode, Pharyngodon wandillahensis. 3. On five monthly occasions, the locations of all individual lizards in three study plots were used to construct weighted, undirected networks based on proximity of adjacent burrows. 4. The networks were used to explore alternative hypotheses about the spread of each parasite through the population: that stable population members that remained in the same burrow over the study period played a major role in influencing the pattern of infection or that dispersing individuals played a more significant role. 5. For ticks, host individuals that were infected were more connected in the network than uninfected hosts and this relationship remained significant for connections to residents in the population, but not for connections to dispersers. 6. For nematodes, infected and uninfected hosts did not differ in their overall strength of connection in the network, but infected hosts were more connected to dispersers than were uninfected hosts, suggesting that lizards moving across the population are the major agents for the transmission of nematodes. 7. This study shows how network analyses can provide new insights into alternative pathways of parasite spread in wildlife populations, where it is difficult to make direct observations of transmission-related behaviours.     

For debate . . . Individual contributions to multiauthor papers.

The curricula vitae of four candidates for a professorial appointment at Athens University were examined to estimate the actual contribution of each candidate to the papers of which he was a coauthor. A total of 879 research papers by the four candidates were analysed in terms of the number of authors, the sequence of names, and the year of publication. The four authors presented 364, 349, 96, and 70 papers. If an equal contribution of all coauthors is assumed, the actual number of papers (all papers divided by the number of authors), is about 106, 83, 28, and 26, respectively, so that the rank of the four candidates did not change. On the assumption that the contribution was related to the candidate''s position in the order of the coauthors'' names, the numbers of papers were corrected to 84, 95, 26, 33 using one statistical method and to 88, 94, 28, 31 using another. These assumptions may not be valid, however, especially as the last author may be more important than the intermediate ones. It is suggested that the journals require authors to state their specific contribution to a paper, such as original idea, planning, collecting data, writing up, etc.     

The axial ligand and extent of protein folding determine whether Zn or Cu binds to amicyanin

M98Q amicyanin is isolated with zinc bound to its type 1 copper-binding site. The influence of the axial ligand of the type 1 copper site on metal specificity is strongest prior to the completion of protein folding and adoption of the final type 1 site geometry. The preference for zinc over copper correlated with the selectivity of apoamicyanin in vitro in the partially folded, rather than the completely folded state. These results suggest that metal incorporation in vivo occurs during protein folding in the periplasm and not to a preformed type 1 site.     

The balance between different peptidoglycan precursors determines whether Escherichia coli cells will elongate or divide.

The rodA(Sui) mutation allows cell division to take place at 42 degrees C in ftsI23 mutant cells, which produce a thermolabile penicillin-binding protein 3 (PBP3, the septation-specific peptidoglycan transpeptidase). We show here that the mutation in rodA is a single-base change from a glutamine to a chain termination (amber) codon, and that an amber suppressor (supE) present in the strain restores the ability to produce a reduced level of normal RodA protein. The reduced level of RodA is accompanied by an increase in the levels of two other proteins (PBP2 and PBP5) encoded by genes in the rodA operon. We show that an increased level of PBP5 is by itself sufficient to restore cell division to ftsI23 cells at 42 degrees C. Two other treatments were found to restore division capacity to the mutant: an increase in PBP6 (which is a D-alanine carboxypeptidase like PBP5) or suitable concentrations of D-cycloserine. All of the above treatments have the effect of reducing the number of pentapeptide side chains in peptidoglycan and increasing the number of tripeptides. We conclude that the effect of the rodA(Sui) mutation is to indirectly increase the availability of tripeptide side chains, which are used preferentially by PBP3 as acceptors in transpeptidation. A change in the proportions of different kinds of peptide side chain in the peptidoglycan can therefore determine whether cells will divide.