Coincident plasmids and antimicrobial resistance in marine bacteria isolated from polluted and unpolluted Atlantic Ocean samples

Sewage effluent and outfall confluence samples were collected at the Barceloneta Regional Treatment Plant in Barceloneta, Puerto Rico; outfall confluence samples at Ocean City, Md., were also collected. Samples from uncontaminated open ocean areas served as clean-water controls. Bacteria were enriched in marine broth 2216 amended with 1 microgram of one of a set of chemicals selected for study per ml: nitrobenzene, dibutyl phthalate, m-cresol, o-cresol, 4-nitroaniline, bis(tributyltin) oxide, and quinone. MICs of the chemicals were determined individually for all isolates. Bacterial isolates were evaluated for resistance to nine different antibiotics and for the presence of plasmid DNA. Treated sewage was found to contain large numbers of bacteria simultaneously possessing antibiotic resistance, chemical resistance, and multiple bands of plasmid DNA. Bacteria resistant to penicillin, erythromycin, nalidixic acid, ampicillin, m-cresol, quinone, and bis(tributyltin) oxide were detected in nearly all samples, but only sewage outfall confluence samples yielded bacterial isolates that were resistant to streptomycin. Bacteria resistant to a combination of antibiotics, including kanamycin, chloramphenicol, gentamicin, and tetracycline, were isolated only from sewage effluent samples. It is concluded that bacterial isolates derived from toxic chemical wastes more frequently contain plasmid DNA and demonstrate antimicrobial resistance than do bacterial isolates from domestic sewage-impacted waters or from uncontaminated open ocean sites.     

A total extract dot blot hybridization procedure for mRNA quantitation in small samples of tissues or cultured cells

A simple method for the estimation of specific mRNA concentrations in small tissue samples (as little as 1 mg) or cultured cells (lower limit 10(5) cells) is described. Guanidine hydrochloride extracts of whole cells or tissues are applied directly onto nitrocellulose and hybridized with the appropriate nick-translated probe. Loading according to DNA content allows expression of the result as concentration per cell. Hybridizing with a ribosomal RNA probe allows expression of results relative to rRNA and estimation of the RNA/DNA ratio in the sample. We describe the application of this procedure to the measurement of ceruloplasmin mRNA in tissues and cultured hepatocytes.     

Bacterial detoxification of diisopropyl fluorophosphate

The ability of 18 gram-negative bacterial isolates to detoxify diisopropyl fluorophosphate, a structural analog of the agents soman and sarin, was investigated. Detoxification by both frozen cell sonicates and acetone powders was assayed by two methods, i.e., the hydrolytic release of fluoride, measured by a fluoride-specific ion electrode, and the disappearance of acetylcholinesterase inhibition in vitro. Frozen cell sonicates for all strains exhibited some activity (F- ion release). In general, acetone powder preparations produced higher activity than frozen cell sonicates did, and the highest activities were exhibited by strains with known parathion hydrolase activity. Two ranges in activity were observed, low level, ranging from 0.1 to 7.0 mumol/min per g of protein, and high level, detected only in parathion hydrolase-producing strains, from 47 to greater than 300 mumol/min per g of protein. Results indicate that parathion hydrolase was nonspecific in phosphoesterase activity. Also, it was an effective detoxicant at low concentrations and near-neutral pH.     

Gut microbiota composition is associated with environmental landscape in honey bees

There is growing recognition that the gut microbial community regulates a wide variety of important functions in its animal hosts, including host health. However, the complex interactions between gut microbes and environment are still unclear. Honey bees are ecologically and economically important pollinators that host a core gut microbial community that is thought to be constant across populations. Here, we examined whether the composition of the gut microbial community of honey bees is affected by the environmental landscape the bees are exposed to. We placed honey bee colonies reared under identical conditions in two main landscape types for 6 weeks: either oilseed rape farmland or agricultural farmland distant to fields of flowering oilseed rape. The gut bacterial communities of adult bees from the colonies were then characterized and compared based on amplicon sequencing of the 16S rRNA gene. While previous studies have delineated a characteristic core set of bacteria inhabiting the honey bee gut, our results suggest that the broad environment that bees are exposed to has some influence on the relative abundance of some members of that microbial community. This includes known dominant taxa thought to have functions in nutrition and health. Our results provide evidence for an influence of landscape exposure on honey bee microbial community and highlight the potential effect of exposure to different environmental parameters, such as forage type and neonicotinoid pesticides, on key honey bee gut bacteria. This work emphasizes the complexity of the relationship between the host, its gut bacteria, and the environment and identifies target microbial taxa for functional analyses.     

A REEVALUATION OF THE DISCONTINUITY PLATE IN PSORALEEAE AND AMORPHEAE (LEGUMINOSAE)

The discontinuity plate, once thought to be a unique feature of the Leguminous tribes Psoraleeae and Amorpheae, has been used as evidence for a close relationship of the two tribes. It is here further studied for taxonomic utility. It is shown that the discontinuity plate comprises four phenomena, distributed in four tribes. Tribe Amorpheae has a discontinuity between the pedicellar and gynoecial traces with a profusion of tracheids at the junction of the gynoecial vascular traces, forming a plate-like structure. This is present and developed at very early stages of the flower and corresponds to the discontinuity plate as originally described. Segregate genera of Psoralea as proposed by Stirton (1981) and Rydberg (1919) also have distinctive vascular features, though these are not the same as the discontinuity plate found in Amorpheae. Psoralea, Otholobium, and all New World genera of Psoraleeae have simple delayed maturation of xylem through the receptacle. Some species of Tephrosia (Tephrosieae) were found to have a similar development. Cullen and Bituminaria (Psoraleeae) have delayed maturation of xylem with an inverted cone-like structure developing in early fruit. A similar structure was found in species of Desmodium (Desmodieae). Because the discontinuity plate is shown to comprise more than one phenomenon, and since these vascular irregularities are now known in four tribes, the discontinuity plate does not necessarily indicate a close relationship between the tribes Psoraleeae and Amorpheae. Furthermore, the phenomena cannot be assumed to be homologous. More complete developmental studies and a larger survey of the Papilionoideae is needed before the vascular features can be confidently used in systematic hypotheses.     

GASTRIC RESECTION—Preoperative and Postoperative Care

Perhaps in no other field of surgery does attention to minute detail play so important a role in determining success as it does in gastric operations.As surgery of the stomach develops toward even greater security and favorable results can be expected with greater confidence, the several aspects of preoperative and postoperative care hitherto regarded as secondary demand closer consideration.