Chemical Composition of the Essential Oils of Three Endemic Species of Anthemis Sect. Hiorthia (DC.) R.Fern. Growing Wild in Sicily and Chemotaxonomic Volatile Markers of the Genus Anthemis L.: An Update

The chemical composition of the essential oils isolated from the aerial parts of Anthemis pignattiorum Guarino, Raimondo & Domina and A. ismelia Lojac . and the aerial parts and flowers of Anthemis cupaniana Tod . ex Nyman , three endemic Sicilian species belonging to the section Hiorthia, was determined by GC‐FID and GC/MS analyses. (Z)‐Muurola‐4(14),5‐diene (27.3%) was recognized as the main constituent of the A. pignattiorum essential oil, together with isospathulenol (10.6%), sabinene (7.7%), and artemisyl acetate (6.8%), while in the oil obtained from the aerial parts of A. ismelia, geranyl propionate (8.8%), bornyl acetate (7.9%), β‐thujone (7.8%), neryl propionate (6.5%), and τ‐muurolol (6.5%) prevailed. α‐Pinene was the main compound of both the aerial part and flower oils of A. cupaniana (18.4 and 13.2%, resp.). Also noteworthy are the considerable amounts of artemisyl acetate (12.7%) and β‐thujone (11.8%) found in the oil from the aerial parts and those of tricosane (9.8%) and sabinene (7.6%) evidenced in the flower oil. Furthermore, an update on the main compounds identified in the essential oils of all the Anthemis taxa studied so far was presented, and cluster analyses were carried out, to compare the essential oils of these taxa.     

Coronary involvement in Mediterranean spotted fever

Mediterranean spotted fever (MSF) is a tick-borne acute febrile disease caused by Rickettsia conorii and characterized by fever, a maculo-papular rash and a black eschar at the site of the tick bite. We describe the case of a 3-year-old boy with MSF who developed a transient right coronary artery ectasia. The patient was brought to the hospital after four days of fever and mild myalgia of the legs. The suspicion of MSF arose due to the presence of a maculo-papular skin rash and treatment with oral clarithromycin was started. After four days fever persisted and the differential diagnosis of Kawasaki syndrome was considered. Echocardiography showed a dilated right coronary artery with hyperreflective walls. Treatment with intravenous immunoglobulin was initiated while clarithromycin was continued. After one day the fever disappeared. An immunofluorescent antibody test performed after four weeks confirmed a R. conorii infection. A follow-up echocardiography was normal six weeks and six months later. We suggest that ectasia of the coronary arteries may be a manifestation of rickettsial vasculitis. Prospective studies are needed to understand the frequency and the possible consequences of this phenomenon in the course of MSF.     

Development of a chemically defined medium for the production of the antibiotic platensimycin by Streptomyces platensis

The actinomycete Streptomyces platensis produces two compounds that display antibacterial activity: platensimycin and platencin. These compounds were discovered by the Merck Research Laboratories, and a complex insoluble production medium was reported. We have used this medium as our starting point in our studies. In a previous study, we developed a semi-defined production medium, i.e., PM5. In the present studies, by varying the concentration of the components of PM5, we were able to develop a superior semi-defined medium, i.e., PM6, which contains a higher concentration of lactose. Versions of PM6, containing lower concentrations of all components, were also found to be superior to PM5. The new semi-defined production media contain dextrin, lactose, MOPS buffer, and ammonium sulfate in different concentrations. We determined antibiotic production capabilities using agar diffusion assays and chemical assays via thin-layer silica chromatography and high-performance liquid chromatography. We reduced crude nutrient carryover from the seed medium by washing the cells with distilled water. Using these semi-defined media, we determined that addition of the semi-defined component soluble starch stimulated antibiotic production and that it and dextrin could both be replaced with glucose, resulting in the chemically defined medium, PM7.     

Glucuronate complexes with Mg2+, Ca2+, Zn2+ and Cd2+ in aqueous chloride solution: a possible chemical speciation model for biochemical understanding

ABSTRACT

Protonation constants and Na⁺-, Mg²⁺-, Ca²⁺-, Zn²⁺- and Cd²⁺-D-Glucuronate complex formation constants have been determined potentiometrically in different ionic strength conditions. Glucuronate forms a very weak complex species with Na⁺ (K ～ 1 dm³ mol^?1), and weak species with Mg²⁺ and Ca²⁺ (K ～ 10 dm³ mol^?1). When glucuronate interacts with Zn²⁺ and Cd²⁺, two species, M(gluc) and M(gluc)₂ (glue = glucuronate) having a stability intermediate between that of mono and dicarboxylate complexes, are formed. This can be due to the involvement of the ethereal oxygen in the coordination. Medium effects are considered in the light of speciation problems.     

G protein-coupled receptor oligomerization provides the framework for signal discrimination

The idea that G protein-coupled receptors (GPCRs) may undergo homo- or hetero-oligomerization, although highly controversial up to a few years ago, has recently gained wide acceptance. The recognition that GPCRs may exhibit either dimeric or oligomeric structures is based upon a large body of biochemical and biophysical evidence. While much effort has been spent to demonstrate the mechanism(s) by which GPCRs interact with each other, the physiological relevance of this phenomenon remains rather elusive. GPCR oligomerization has been proposed to play a role in receptor ontogeny by either chaperoning protein folding or controlling trafficking to the cell surface. However, the acquisition of these roles does not rule out the possibility that oligomeric receptors may have additional functions, once they are brought to the cell surface. Herein, we propose that protein-protein as well as protein-lipid interactions may provide the structural basis for organizing distinct cell compartments along the plasma membrane where different extracellular signals may be perceived and discriminated.     

Comorbidities and Disease Severity as Risk Factors for Carbapenem-Resistant Klebsiella pneumoniae Colonization: Report of an Experience in an Internal Medicine Unit

Background

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is an emerging multidrug-resistant nosocomial pathogen, spreading to hospitalized elderly patients. Risk factors in this setting are unclear. Our aims were to explore the contribution of multi-morbidity and disease severity in the onset of CRKP colonization/infection, and to describe changes in epidemiology after the institution of quarantine-ward managed by staff-cohorting.

Methods and Findings

With a case-control design, we evaluated 133 CRKP-positive patients (75 M, 58 F; mean age 79±10 years) and a control group of 400 CRKP-negative subjects (179 M, 221 F; mean age 79±12 years) admitted to Internal Medicine and Critical Subacute Care Unit of Parma University Hospital, Italy, during a 10-month period. Information about comorbidity type and severity, expressed through Cumulative Illness Rating Scale-CIRS, was collected in each patient. During an overall 5-month period, CRKP-positive patients were managed in an isolation ward with staff cohorting. A contact-bed isolation approach was established in the other 5 months. The effects of these strategies were evaluated with a cross-sectional study design. CRKP-positive subjects had higher CIRS comorbidity index (12.0±3.6 vs 9.1±3.5, p<0.0001) and CIRS severity index (3.2±0.4 vs 2.9±0.5, p<0.0001), along with higher cardiovascular, respiratory, renal and neurological disease burden than control group. CIRS severity index was associated with a higher risk for CRKP-colonization (OR 13.3, 95%CI6.88–25.93), independent of comorbidities. Isolation ward activation was associated with decreased monthly incidence of CRKP-positivity (from 16.9% to 1.2% of all admissions) and infection (from 36.6% to 22.5% of all positive cases; p = 0.04 derived by Wilcoxon signed-rank test). Mortality rate did not differ between cases and controls (21.8% vs 15.2%, p = 0.08). The main limitations of this study are observational design and lack of data about prior antibiotic exposure.

Conclusions

Comorbidities and disease severity are relevant risk factors for CRKP-colonization/infection in elderly frail patients. Sanitary measures may have contributed to limit epidemic spread and rate of infection also in internal medicine setting.     

The hydrophobic mismatch determines the miscibility of ceramides in lipid monolayers

The organization of lipids within membranes strongly depends on the interaction with other lipid and protein molecules. Sphingolipids comprise a structurally diverse family, the ceramides being some of the simplest members. Although small chemical modifications of ceramide structure, such as varying the N-acyl chain length, lead to a complex polymorphism of this lipid, only long acyl chain ceramides have usually been studied and their properties became a putative hallmark for all ceramides. In this work, we studied the mixing behavior of C10:0 Cer, which has the N-acyl chain shorter than that of the sphingosine acyl chain and displays an expanded to condensed phase transition at 25mNm(-1) at 24°C, with ceramides N-acylated with longer fatty acyl chains C12:0, C14:0 and C18:0. The N-acyl chain length determined the miscibility of ceramides in Langmuir monolayers, as it was ascertained by the dependence of the mean molecular area, perpendicular dipole moment, surface topography and film thickness with the mixture composition. We found that, as the hydrophobic mismatch in ceramides increased complete miscibility, partial or complete immiscibility can occur.     

A molecular analysis of some Eastern Atlantic grouper from the Epinephelus and Mycteroperca genus

Mitochondrial cytochrome b (397 bp) and 16S rDNA (516 bp) sequences analysis was used to investigate the phylogenetic relationships among some Eastern Atlantic Epinephelinae species. Six species of Epinephelus (E. aeneus, E. caninus, E. costae, E. haifensis, E. marginatus and E. tauvina) and two species of Mycteroperca (M. rubra and M. fusca) were analysed. Neighbour-joining and maximum-parsimony analysis support the paraphyletic grouping of the Epinephelus and Mycteroperca analysed. The maximum pairwise nucleotide divergence value in cyt b among all taxa was 0.196 between E. aeneus and E. marginatus and the minimum value was 0.006 between E. costae and M. rubra. Meanwhile, in 16S sequence analysis, the maximum value is 0.093 between E. aeneus and E. tauvina and the minimum value is 0.011 between E. marginatus and M. rubra. Molecular clock estimates for the species suggest a divergence time of 20-24 mya, which coincides with the Miocene period. A molecular analysis was also conducted, using other Epinephelinae sequences from GenBank in order to improve our understanding of the phyletic status of the Epinephelus and Mycteroperca species analysed.     

Composition-driven Surface Domain Structuring Mediated by Sphingolipids and Membrane-active Proteins

Biomembranes contain a wide variety of lipids and proteins within an essentially two-dimensional structure. The coexistence of such a large number of molecular species causes local tensions that frequently relax into a phase or compositional immiscibility along the lateral and transverse planes of the interface. As a consequence, a substantial microheterogeneity of the surface topography develops and that depends not only on the lipid-protein composition, but also on the lateral and transverse tensions generated as a consequence of molecular interactions. The presence of proteins, and immiscibility among lipids, constitute major perturbing factors for the membrane sculpturing both in terms of its surface topography and dynamics. In this work, we will summarize some recent evidences for the involvement of membrane-associated, both extrinsic and amphitropic, proteins as well as membrane-active phosphohydrolytic enzymes and sphingolipids in driving lateral segregation of phase domains thus determining long-range surface topography.