Genome Sequence of Staphylococcus epidermidis Strain AU12-03, Isolated from an Intravascular Catheter

In recent years, Staphylococcus epidermidis has become a major nosocomial pathogen and the most common cause of intravascular catheter-related bacteremia, which can increase morbidity and mortality and significantly affect patient recovery. We report a draft genome sequence of Staphylococcus epidermidis AU12-03, isolated from an intravascular catheter tip.     

Phagocytosis is coupled to the formation of phagosome-associated podosomes and a transient disruption of podosomes in human macrophages

Phagocytosis consists in ingestion and digestion of large particles, a process strictly dependent on actin re-organization. Using synchronized phagocytosis of IgG-coated latex beads (IgG-LB), zymosan or serum opsonized-zymosan, we report the formation of actin structures on both phagocytic cups and closed phagosomes in human macrophages. Their lifespan, size, protein composition and organization are similar to podosomes. Thus, we called these actin structures phagosome-associated podosomes (PAPs). Concomitantly to the formation of PAPs, a transient disruption of podosomes occurred at the ventral face of macrophages. Similarly to podosomes, which are targeted by vesicles containing proteases, the presence of PAPs correlated with the maturation of phagosomes into phagolysosomes. The ingestion of LB without IgG did not trigger PAPs formation, did not lead to podosome disruption and maturation to phagolysosomes, suggesting that these events are linked together. Although similar to podosomes, we found that PAPs differed by being resistant to the Arp2/3 inhibitor CK666. Thus, we describe a podosome subtype which forms on phagosomes where it probably serves several tasks of this multifunctional structure.     

Predator detection and avoidance by starlings under differing scenarios of predation risk

Practically all animals must find food while avoiding predators.An individual's perception of predation risk may depend on manyfactors, such as distance to refuge and group size, but it isunclear whether individuals respond to different factors ina similar manner. We tested whether flocks of foraging starlingsresponded in the same way to an increased perception of predationrisk by assessing three factors: (1) neighbor distances, (2)habitat obstruction, and (3) recent exposure to a predator.We found that in all three scenarios of increased risk, starlingsreduced their interscan intervals (food-searching bouts), whichincreased the frequency of their vigilance periods. We thenexamined how one of these factors, habitat obstruction, affectedescape speed by simulating an attack with a model predator.Starlings were slower to respond in visually obstructed habitats(long grass swards) and slower when they had their head downin obstructed habitats than when they had their head down inopen habitats. In addition, reaction times were quicker whenstarlings could employ their peripheral fields of vision. Ourresults demonstrate that different sources of increased riskcan generate similar behavioral responses within a species.The degree of visibility in the physical and social environmentaffects both the actual and perceived risk of predation.     

Abortion is incommensurable with fetal alcohol syndrome

A recent article argued for the immorality of abortion regardless of personhood status by comparing the impairment caused by fetal alcohol syndrome to the impairment caused by abortion. I argue that two of the premises in this argument fail and that, as such, one cannot reasonably attribute moral harms to abortion on the basis of the moral harms caused by fetal alcohol syndrome. The impairment argument relies on an inconsistent instantiation, which undermines the claim that personhood is irrelevant, and it does not fulfill its own ceteris paribus clause, which demands that no additional benefit be gained from abortion that would not be gained from causing fetal alcohol syndrome.     

Cloning of the Zea mays controlling element Ac from the wx-m7 allele

Summary The cloning of the controlling element Ac from the wx-m7 allele of Zea mays is described. The cloned fragment carries a 4.3 kb insertion that by restriction analysis is indistinguishable from the Ac insertion in Ac wx-m9. It is located approximately 2.5 kb upstream of the Ac wx-m9 insertion. Offprint requests to: P. Starlinger     

RECENT APPEARANCE OF CYLINDROSPEMOPSIS (CYANOBACTEIUA) IN FIVE HYPEREUTROPHIC FLORIDA LAKES1

Observations of historical and recent phytoplankton samples from five hypereutrophic Florida lakes indicate that nitrogen-fixing cyanobacteria in the genus Cylindrospermopsis Seenayya et Subba Raju have entered these water-bodies sometime in the last 30 years. Cylindrospermopsis forms a year-round bloom in one of the five lakes, dominates seasonally in another, and is at least at times an important component of the phytoplankton community in the remaining three. The increase in abundance of Cylindrospermopsis in Florida lakes could have implications for water management.     

Influence of Nutrient Concentrations on MPN Quantification and Enrichment of Nitrate-Reducing Fe(II)-Oxidizing and Fe(III)-Reducing Bacteria from Littoral Freshwater Lake Sediments

The application of culture-dependent studies to quantify Fe-metabolizing microorganisms from the environment is a necessity, as there are so far no universal functional marker genes for application in culture-independent studies. Media composition can vary between studies, therefore, we determined the effects of three different growth media on the quantification (MPNs) and identity (via cloning and sequencing of dominant DGGE bands) of nitrate-reducing Fe(II)-oxidizers and lactate- or acetate-oxidizing Fe(III)-reducers from a lacustrine sediment: low sulphate freshwater medium (FWM), sterile filtered bicarbonate-buffered lake water (BLW) and a mixture of both (MIX). We consistently found fewer cells in the BLW than in the FWM and the MIX. The DGGE banding patterns of the microbial communities enriched in different media types clustered together according to the e^? donor and acceptor couples and not according to the medium used. Thus, although the medium composition significantly influenced the quantification and thereby conclusions on the abundance and potential significance of the targeted group within the ecosystem, biodiversity assessments through enrichment cultures were less influenced by the medium, but instead were affected by the type and concentration of the e^? donor/acceptor.     

Growth Phase-Dependent Regulation of Vsr Endonuclease May Contribute to 5-Methylcytosine Mutational Hot Spots in Escherichia coli

Using rabbit polyclonal antibodies, we have shown that the Dcm cytosine methylase of Escherichia coli is maintained at a constant level during cell growth, while Vsr endonuclease levels are growth phase dependent. Decreased production of Vsr relative to Dcm during the log phase may contribute substantially to the mutability of 5-methylcytosine.     

Role of NK Cell Subsets in Organ-Specific Murine Melanoma Metastasis

Tumor metastasis plays a major role in the morbidity and mortality of cancer patients. Among solid tumors that undergo metastasis, there is often a predilection to metastasize to a particular organ with, for example, prostate cancer preferentially metastasizing to bones and colon cancer preferentially metastasizing to the liver. Although many factors are thought to be important in establishing permissiveness for metastasis, the reasons for organ-specific predilection of each tumor are not understood. Using a B16 murine melanoma model, we tested the hypothesis that organ-specific NK cell subsets play a critical role in organ-specific metastasis of this tumor. Melanoma cells, given intravenously, readily colonized the lungs but not the liver. NK cell depletion (either iatrogenically or by using genetically targeted mice) resulted in substantial hepatic metastasis. Analysis of NK cell subsets, defined by the differential expression of a combination of CD27 and CD11b, indicated a significant difference in the distribution of NK cell subsets in the lung and liver with the mature subset being dominant in the lung and the immature subset being dominant in the liver. Several experimental approaches, including adoptive transfer, clearly indicated that the immature hepatic NK cell subset, CD27+ CD11b–, was protective against liver metastasis; this subset mediated its protection by a perforin-dependent cytotoxic mechanism. In contrast, the more mature NK cell subsets were more efficient at reducing pulmonary tumor load. These data indicate that organ-specific immune responses may play a pivotal role in determining the permissiveness of a given organ for the establishment of a metastatic niche.