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.     

Maximization of Candida utilis cytochromes by pulse additions of ethanol to continuous cultures

Candida utilis was grown with glucose as growth-limiting carbon source in batch culture, steady-state continuous culture, and non-steady-state continuous culture. High cytochrome concentrations were routinely recorded in cells harvested in the latter stages of batch culture. They were occasionally recorded in cells from imprecisely controlled steady-state cultures, but precise control of the steady-state dissolved oxygen tension stabilized the cytochromes at relatively low levels. Controlled non-steady-state continuous cultures, imposed by pulse additions of ethanol, routinely produced cells with high cytochrome concentrations. A mechanism is proposed whereby maintenance of cytochrome derepression in continuous culture is dependent upon indefinitely prolonging an “overshoot” response in gene expression.     

The malmö polymorphism of coagulation factor IX, an immunologic polymorphism due to dimorphism of residue 148 that is in linkage disequilibrium with two other F.IX polymorphisms

A mouse monoclonal antibody (MAB 9.9) to coagulation factor IX (F.IX) detects a polymorphism in the plasma of normal people. Its epitope has been narrowed down to <6 amino acids in the activation peptide of the X-linked F.IX protein. The activation peptide contains a dimorphism—Thr:Ala—at position 148 of the protein. Using synthetic oligonucleotides, we have demonstrated that (1) the F.IX which reacts with 9.9 has Thr at position 148 and (2) that which does not has Ala. Positive reactors (148^thr) are designated Malmö A, and negative reactors (148^ala) are designated Malmö B. The plasma levels of AA women are indistinguishable from those of A men, and both B men and BB women are null against MAB 9.9. The plasma level of Malmö A in AB women is approximately half that of AA women, and “lyonization” is clearly operating in the heterozygotes. The dimorphism is in strong linkage disequilibrium with two other intragenic RFLPs, TaqI and XmnI. Furthermore, intragenic crossing-over—including double crossing-over—appears to have occurred between the three sites. Seven of the eight possible haplotypes have been identified, five in men and two others in women. The immunoassay that identifies ～50% of the AB women in the pool of Malmö A females with 95% confidence identifies men unambiguously as A or B. The assay would be very useful for population-genetic studies of the Malmö epitope if the studies were limited to men.     

Fine needle aspiration biopsy in uveal melanoma

Fine needle aspiration (FNA) biopsies were performed in a series of patients with uveal tumors. Cytopathologic examination established the correct diagnosis in 26 of 29 uveal melanomas. FNA biopsy was able to exclude the diagnosis of a malignant neoplasm in five nonmelanoma tumefactions. Histologic and FNA cytologic typing of melanomas as epithelioid or predominantly spindle cell showed good agreement, with the same classifications made in 14 of 18 cases. FNA biopsy specimens also proved to be adequate for DNA-content and cell-cycling studies. The cessation of cell cycling in successfully irradiated melanomas may be useful in establishing the postradiation status of tumors that have questionable growths after therapy, as was shown using FNA samples in three such cases in this study. The results of this study show that FNA biopsy is a useful diagnostic adjunct in patients with atypical lesions that require therapy.     

Inhibition of Cortisol Secretion by Dexamethasone in Relation to Body Fat Distribution: A Dose-Response Study

In this study, dexamethasone (dex) was administered in random order in doses of 0.05, 0.125, 0.25 and 0.5 mg at 10 p.m. with measurements of serum Cortisol in the morning (8 a.m.) of this and the following day. The test was performed on 22 apparently healthy men, 40 to 60 years of age, recruited from laboratory personnel, outpatient clinics or advertisements in a newspaper. Eight had a body mass index (BMI) (kg/m²) of <25 and 14 of >25. Twelve men had a waist hip ratio (WHR) of <1.0 and 10 men had a WHR of<1.0. Cortisol values at baseline were correlated inversely with WHR and were usually lower in men with a high (>1.0) rather than a low than low (<1.0) WHR after dex inhibition. There was apparently no inhibition by dex at 0.05 and 0.125 mg on average in men with a WHR of >1.0. In addition, the inhibition at 0.5 mg dex correlated negatively with the WHR and was significantly lower (p<0.05) in men with a WHR of >1.0 than in men with a WHR of <1.0. None of these differences or relationships was found to be dependent on BMI. It is concluded that men with an elevated WHR experience a decrease in the inhibition of Cortisol secretion by dex. It is suggested that this could explain or contribute to the elevated sensitivity of their HPA axis. Furthermore, lower morning Cortisol concentrations suggest a change in diurnal secretion patterns.     

Molecular Comparison of Bacterial Communities on Peripheral Intravenous Catheters and Matched Skin Swabs

Skin bacteria at peripheral intravenous catheter (PIVC) insertion sites pose a serious risk of microbial migration and subsequent colonisation of PIVCs, and the development of catheter related bloodstream infections (CRBSIs). Common skin bacteria are often associated with CRBSIs, therefore the bacterial communities at PIVC skin sites are likely to have major implications for PIVC colonisation. This study aimed to determine the bacterial community structures on skin at PIVC insertion sites and to compare the diversity with associated PIVCs. A total of 10 PIVC skin site swabs and matching PIVC tips were collected by a research nurse from 10 hospitalised medical/surgical patients at catheter removal. All swabs and PIVCs underwent traditional culture and high-throughput sequencing. The bacterial communities on PIVC skin swabs and matching PIVCs were diverse and significantly associated (correlation coefficient = 0.7, p<0.001). Methylobacterium spp. was the dominant genus in all PIVC tip samples, but not so for skin swabs. Sixty-one percent of all reads from the PIVC tips and 36% of all reads from the skin swabs belonged to this genus. Staphylococcus spp., (26%), Pseudomonas spp., (10%) and Acinetobacter spp. (10%) were detected from skin swabs but not from PIVC tips. Most skin associated bacteria commonly associated with CRBSIs were observed on skin sites, but not on PIVCs. Diverse bacterial communities were observed at skin sites despite skin decolonization at PIVC insertion. The positive association of skin and PIVC tip communities provides further evidence that skin is a major source of PIVC colonisation via bacterial migration but microbes present may be different to those traditionally identified via culture methods. The results provide new insights into the colonisation of catheters and potential pathogenesis of bacteria associated with CRBSI, and may assist in developing new strategies designed to reduce the risk of CRBSI.     

Prospective Life Cycle Assessment of Epitaxial Graphene Production at Different Manufacturing Scales and Maturity

Epitaxial growth is a potential production process for the new material graphene, where it is grown on silicon carbide (SiC) wafers at high temperatures. We provide first estimates of the life cycle cumulative energy demand, climate change, terrestrial acidification, and eco‐toxicity of this production. For this purpose, we applied prospective life cycle assessment (LCA) for three production scenarios (lab, pilot, and an industrial scenario), which reflect different production scales and technological maturity. The functional unit was one square centimeter of graphene. Results show that the three scenarios have similar impacts, which goes against previous studies that have suggested a decrease with larger production scale and technological maturity. The reason for this result is the dominance of electricity use in the SiC wafer production for all impacts (>99% in the worst case, >76% in the best case). Only when assuming thinner SiC wafers in the industrial scenario is there a reduction in impacts by around a factor of 10. A surface‐area–based comparison to the life cycle energy use of graphene produced by chemical vapor deposition showed that epitaxial graphene was considerably more energy intensive—approximately a factor of 1,000. We recommend producers of epitaxial graphene to investigate the feasibility of thinner SiC wafers and use electricity based on wind, solar, or hydropower. The main methodological recommendation from the study is to achieve a temporal robustness of LCA studies of emerging technologies, which includes the consideration of different background systems and differences in production scale and technological maturity.     

Life-cycle impact assessment methods for physical energy scarcity: considerations and suggestions

The International Journal of Life Cycle Assessment - Most approaches for energy use assessment in life cycle assessment do not consider the scarcity of energy resources. A few approaches consider...     

Resting Stages of Skeletonema marinoi Assimilate Nitrogen From the Ambient Environment Under Dark,Anoxic Conditions

The planktonic marine diatom Skeletonema marinoi forms resting stages, which can survive for decades buried in aphotic, anoxic sediments and resume growth when re-exposed to light, oxygen, and nutrients. The mechanisms by which they maintain cell viability during dormancy are poorly known. Here, we investigated cell-specific nitrogen (N) and carbon (C) assimilation and survival rate in resting stages of three S. marinoi strains. Resting stages were incubated with stable isotopes of dissolved inorganic N (DIN), in the form of ¹⁵N-ammonium (NH₄⁺) or -nitrate (NO₃⁻) and dissolved inorganic C (DIC) as ¹³C-bicarbonate (HCO₃⁻) under dark and anoxic conditions for 2 months. Particulate C and N concentration remained close to the Redfield ratio (6.6) during the experiment, indicating viable diatoms. However, survival varied between <0.1% and 47.6% among the three different S. marinoi strains, and overall survival was higher when NO₃⁻ was available. One strain did not survive in the NH₄⁺ treatment. Using secondary ion mass spectrometry (SIMS), we quantified assimilation of labeled DIC and DIN from the ambient environment within the resting stages. Dark fixation of DIC was insignificant across all strains. Significant assimilation of ¹⁵N-NO₃⁻ and ¹⁵N-NH₄⁺ occurred in all S. marinoi strains at rates that would double the nitrogenous biomass over 77–380 years depending on strain and treatment. Hence, resting stages of S. marinoi assimilate N from the ambient environment at slow rates during darkness and anoxia. This activity may explain their well-documented long survival and swift resumption of vegetative growth after dormancy in dark and anoxic sediments.