J. E. Davis to Messrs, Gunnison, Chapman and Co., Greenville, Mississippi, 5 August

https://egrove.olemiss.edu/ciwar_corresp/1032/thumbnail.jp

Reduced Recharge Capacity of a Pump and Treat System

The North Boundary treatment system at Rocky Mountain Arsenal (RMA), Commerce City, Colorado, involves pumping of contaminated groundwater from an unconfined aquifer from one side of a soil-bentonite (SB) slurry wall to three pulsed-bed activated carbon adsorbers and prefilter and postfilter systems. The treated water is injected into the unconfined aquifer on the other side of the slurry wall via 38 recharge wells and 15 recharge trenches, collectively referred to as the recharge system. Recharge capacity of the recharge system has declined over time, limiting the operating capacity of the system. Two probable causes for reduction of the recharge systems is assessed

Bacteriophage-Resistant Mutants in Yersinia pestis: Identification of Phage Receptors and Attenuation for Mice

Background: Bacteriophages specific for Yersinia pestis are routinely used for plague diagnostics and could be an alternative to antibiotics in case of drug-resistant plague. A major concern of bacteriophage therapy is the emergence of phageresistant mutants. The use of phage cocktails can overcome this problem but only if the phages exploit different receptors. Some phage-resistant mutants lose virulence and therefore should not complicate bacteriophage therapy. Methodology/Principal Findings: The purpose of this work was to identify Y. pestis phage receptors using site-directed mutagenesis and trans-complementation and to determine potential attenuation of phage-resistant mutants for mice. Six receptors for eight phages were found in different parts of the lipopolysaccharide (LPS) inner and outer core. The receptor for R phage was localized beyond the LPS core. Most spontaneous and defined phage-resistant mutants of Y. pestis were attenuated, showing increase in LD 50 and time to death. The loss of different LPS core biosynthesis enzymes resulted in the reduction of Y. pestis virulence and there was a correlation between the degree of core truncation and the impact on virulence. The yrbH and waaA mutants completely lost their virulence. Conclusions/Significance: We identified Y. pestis receptors for eight bacteriophages. Nine phages together use at least seven different Y. pestis receptors that makes some of them promising for formulation of plague therapeutic cocktails. Most phage-resistant Y. pestis mutants become attenuated and thus should not pose a serious problem for bacteriophag

Rapid and Sensitive Detection of Yersinia pestis Using Amplification of Plague Diagnostic Bacteriophages Monitored by Real-Time PCR

BACKGROUND: Yersinia pestis, the agent of plague, has caused many millions of human deaths and still poses a serious threat to global public health. Timely and reliable detection of such a dangerous pathogen is of critical importance. Lysis by specific bacteriophages remains an essential method of Y. pestis detection and plague diagnostics. METHODOLOGY/PRINCIPAL FINDINGS: The objective of this work was to develop an alternative to conventional phage lysis tests--a rapid and highly sensitive method of indirect detection of live Y. pestis cells based on quantitative real-time PCR (qPCR) monitoring of amplification of reporter Y. pestis-specific bacteriophages. Plague diagnostic phages phiA1122 and L-413C were shown to be highly effective diagnostic tools for the detection and identification of Y. pestis by using qPCR with primers specific for phage DNA. The template DNA extraction step that usually precedes qPCR was omitted. phiA1122-specific qPCR enabled the detection of an initial bacterial concentration of 10(3) CFU/ml (equivalent to as few as one Y. pestis cell per 1-microl sample) in four hours. L-413C-mediated detection of Y. pestis was less sensitive (up to 100 bacteria per sample) but more specific, and thus we propose parallel qPCR for the two phages as a rapid and reliable method of Y. pestis identification. Importantly, phiA1122 propagated in simulated clinical blood specimens containing EDTA and its titer rise was detected by both a standard plating test and qPCR. CONCLUSIONS/SIGNIFICANCE: Thus, we developed a novel assay for detection and identification of Y. pestis using amplification of specific phages monitored by qPCR. The method is simple, rapid, highly sensitive, and specific and allows the detection of only live bacteria

Ancient origin of the biosynthesis of lignin precursors

BACKGROUND: Lignin plays an important role in plant structural support and water transport, and is considered one of the hallmarks of land plants. The recent discovery of lignin or its precursors in various algae has raised questions on the evolution of its biosynthetic pathway, which could be much more ancient than previously thought. To determine the taxonomic distribution of the lignin biosynthesis genes, we screened all publicly available genomes of algae and their closest non-photosynthetic relatives, as well as representative land plants. We also performed phylogenetic analysis of these genes to decipher the evolution and origin(s) of lignin biosynthesis. RESULTS: Enzymes involved in making p-coumaryl alcohol, the simplest lignin monomer, are found in a variety of photosynthetic eukaryotes, including diatoms, dinoflagellates, haptophytes, cryptophytes as well as green and red algae. Phylogenetic analysis of these enzymes suggests that they are ancient and spread to some secondarily photosynthetic lineages when they acquired red and/or green algal endosymbionts. In some cases, one or more of these enzymes was likely acquired through lateral gene transfer (LGT) from bacteria. CONCLUSIONS: Genes associated with p-coumaryl alcohol biosynthesis are likely to have evolved long before the transition of photosynthetic eukaryotes to land. The original function of this lignin precursor is therefore unlikely to have been related to water transport. We suggest that it participates in the biological defense of some unicellular and multicellular algae. REVIEWERS: This article was reviewed by Mark Ragan, Uri Gophna, Philippe Deschamps

STUDIES ON ANTIBIOTIC SYNERGISM AND ANTAGONISM : Synergism among Seven Antibiotics against Various Bacteria in vitro

In an increasing nuimber of microbial infections of man, treatment with single antibiotics fails to cure. Some of these infections, however, respond favorably to combined treatment with two antibiotic drugs. Certain pairs of these drugs have proved successful in a limited number of clinical situations. An outstand-ing example is the frequent cure of bacterial endocarditis due to enterococci by the simultaneous administration of penicillin and streptomycin, whereas neither of these drugs alone cures more than a small number of cases (Hunter, 1950; Robbins and Tompsett, 1951; Cates, Christie, and Garrod, 1951). The synergism of penicillin and streptomycin in vitro is manifested by a marked in-crease in the bactericidal rate beyond that obtainable with any concentration of either drug alone and also by the killing of the entire exposed bacterial popu-lation, a feat which neither of the two drugs can achieve alone (Jawetz, Guinnison, and Coleman, 1950; Gunnison, Jawetz, and Coleman, 1950). As more microorganisms which are resistant to certain antibiotics are encoun-tered in medical practice, there is an increased temptation to employ more than one antimicrobial drug routinely. Such indiscriminate use of two drugs is probably inadvisable inasmuch as antagonism between certain antibiotics has been dem-onstrated both in vitro and in experimental animals (Jawetz, Gunnison, Speck, and Coleman, 1951; Speck, Jawetz, and Gunnison, 1951; Jawetz, Gunnison, and Speck, 1951). To obtain a rational basis for the selection of antibiotics for com-bined therapy it is essential that the relationships among these drugs be studied. This report deals with some quantitative relationships in several synergistic combinations of antibiotics active against a number of different bacteria. The results may contribute clues to the mechanism of combined antibiotic action. An attempt has been made to answer some of the questions which arise as to the combined effect of two antibiotics in vitro

Best Management Practices for Conserving the Karner Blue Butterfly and Its Habitat

The Karner blue butterfly, Plebejus melissa samuelis, is a critically endangered butterfly on the brink of extinction. The Karner blue butterfly, KBB, survival is dependent on the wild lupine plant, Lupinus perennis, which grows in oak savannas and pine barrens and thrives in full sun to partial shade with sandy soils. The butterfly has two broods each year, where they lay eggs on the wild lupine stems and leaves or nearby grasses and sedges. The larvae only consume the leaves of wild lupine, while adults obtain nectar from a variety of plants. Since the survival of the KBB is contingent on wild lupine, management and conservation of wild lupine and other nectar sources is critical to maintaining and growing KBB populations