Effectiveness of antibiotics in preventing meningococcal disease after a case: systematic review

Objective To summarise the evidence for the role of antibiotics in preventing further cases of meningococcal disease through chemoprophylaxis given to the index patient, household contacts, and children in day care settings after a single case.Design Systematic review.Methods Studies were identified by searching Embase (1983-2003), Medline (1965-2003), and CAB Health (1973-2003) and by contacting the World Health Organization and the European meningococcal disease surveillance network and examining references of identified papers. The review included all studies with at least 10 cases in which outcomes were compared between treated and untreated groups.Main outcome measure Subsequent cases of meningococcal disease 1-30 days after onset of disease in the index patient.Results Four observational studies and one small trial met the inclusion criteria. Meta-analysis of studies on chemoprophylaxis given to household contacts showed a significant reduction in risk (risk ratio 0.11, 95% confidence interval 0.02 to 0.58). The number needed to treat to prevent a case was estimated as 218 (121 to 1135). Primary outcome data were not available in studies of chemoprophylaxis given to the index patient: when prophylaxis had not been given, rate of carriage after discharge from hospital was estimated as 3% (0 to 6), probably an underestimate of the true rate. No studies of chemoprophylaxis in day care settings were identified that met the inclusion criteria.Conclusion There have been no high quality experimental trials looking at control policies for meningococcal disease. The best available evidence is from retrospective studies. The risk of meningococcal disease in household contacts of a patient can be reduced by an estimated 89% if they take antibiotics known to eradicate meningococcal carriage. Chemoprophylaxis should be recommended for the index patient and all household contacts.     

Localization and transmission route of Coriobacterium glomerans, the endosymbiont of pyrrhocorid bugs

Endosymbiotic gut bacteria play an essential role in the nutrition of many insects. Most of the nutritional interactions investigated so far involve gammaproteobacterial symbionts, whereas other groups have received comparatively little attention. Here, we report on the localization and the transmission route of the specific actinobacterial symbiont Coriobacterium glomerans from the gut of the red firebug, Pyrrhocoris apterus (Hemiptera: Pyrrhocoridae ). The symbionts were detected by diagnostic PCRs and FISH in the midgut section M3, in the rectum and in feces of the bugs as well as in the hemolymph of some females. Furthermore, adult female bugs apply the symbionts to the surface of the eggs during oviposition, from where they are later taken up by the hatchlings. Surface sterilization of egg clutches generated aposymbiotic insects and thereby confirmed the vertical transmission route via the egg surface. However, symbionts were readily acquired horizontally when the nymphs were reared in the presence of symbiont-containing eggshells, feces, or adult bugs. Using diagnostic PCRs and partial sequencing of the 16S rRNA gene, closely related bacterial symbionts were detected in the cotton stainer bug Dysdercus fasciatus (Hemiptera: Pyrrhocoridae ), suggesting that the symbiosis with Actinobacteria may be widespread among pyrrhocorid bugs.     

β-arrestins attenuate p38-mediated endosome to Golgi transport

Shiga toxin (Stx) is after endocytosis transported via early endosomes to the Golgi apparatus and endoplasmic reticulum. It is then translocated to the cytosol where it exerts its toxic effect. We recently reported that p38 is required for endosome to Golgi transport of Stx. In the present study, we investigated whether β-arrestins are effectors of this pathway. β-arrestin knockdown led to enhanced Stx transport. A similar phenotype was achieved upon p38 activation. We demonstrate that p38 and β-arrestin act on the same pathway. β-arrestin colocalized with internalized Stx and, interestingly, was recruited to endosomes upon p38 activation. After Stx treatment, p38 and β-arrestin formed a transient complex. From these data we propose that β-arrestin negatively regulates Stx transport via an interaction with activated p38 and attenuation of its signalling. Interestingly, also mannose 6-phosphate receptor transport was regulated by p38 and β-arrestin. β-arrestins therefore seem to regulate an endosome to Golgi pathway used by multiple cargo proteins.     

Molecular cloning of Odf3 encoding a novel coiled-coil protein of sperm tail outer dense fibers.

The outer dense fibers (ODF) are the main cytoskeletal structures of the sperm tail found in animals with internal fecundation. They consist of at least 14 polypeptides from which only a few are identified due to difficulties in isolation of the protein components. Here we report the isolation and molecular characterization of Odf3, encoding a novel protein of rat sperm ODF. Odf3 is transcribed in testes and more specifically in spermatids but it is also expressed in epididymides and brain suggesting a possible involvement in building of the cellular cytoskeleton. Odf3 encodes a putative protein of approximately 110 kDa. Secondary structure predictions indicated that ODF3 is a coiled-coil protein. The identification of coiled-coil proteins as constituents of outer dense fibers reveals a model for ODF formation.     

Wirkung von EDTA auf Sporulation,Kompetenz und potentielle Tranformanten von Bacillus subtilis

Zusammenfassung 1–5·10^–4 M EDTA verhinderte selektiv die Sporenbildung, wenn es zur Zeit t ₀–t ₃ zu Stickstoff-limitierten Bacillus subtilis-Kulturen gegeben wurde.EDTA beeinflußte in den genannten Konzentrationen nicht selektiv die Ausbildung kompetenter Zellen, die Transformationsrate war nicht vermindert. Jedoch hatte es eine spezifische stabilisierende Wirkung auf potentielle Transformanten. Aus diesen Ergebnissen wird gefolgert, daß kompetente Zellen keinen sporulationsspezifischen Stoffwechsel aufweisen. Erst, nachdem bei weiterer Bebrütung die Kompetenz verloren gegangen ist, verhalten sich diese Zellen wie Präsporen. Die stabilisierende Wirkung des EDTA auf potentielle Transformanten beruht dann auf der Konservierung des frühen, reversiblen Sporulationsstadiums.Kompetenz scheint ein Präsporulationsstadium zu sein, das ausgebildet wird in den Zellen, die in Anwesenheit von C- und N-Kataboliten zur Sporulation übergehen.

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Action of EDTA on sporulation, competence and potential transformants of Bacillus subtilis

Summary The formation of spores in a nitrogen-limited Bacillus subtilis-culture was suppressed selectively by addition of 1-5·10^-4 M EDTA during the first 3 hours of sporulation.EDTA at the concentrations mentioned did not alter the frequency of transformation when added to a young growing culture. The development of competent cells was not affected to a higher extent than the growth rate. However, a specific action of EDTA on potential transformants could be demonstrated. The presence of EDTA caused their stabilization for more than 5 hours. From these results ist was concluded that there is no sporulation specific metabolism in competent cells. Only after having lost their competence during further incubation they resemble forespores. The stabilizing effect of EDTA on potential transformants may then be caused by conserving the early, reversible phase of sporogenesis.Competence seems to represent a presporulation-state which occurs in cells which are going to sporulate in the presence of C- and N-catabolites.

     

Insect-catching behavior in socially inexperienced infant squirrel monkeys

Insects are an essential component of squirrel monkey natural food. Eight of ten socially inexperienced infant squirrel monkeys, during their 2nd and 3rd month of age, directed their attention to living insects or film presentations of moving insects. They attempted to catch them with gradually improving success, and on at least two occasions consumed them. For comparison, group-living squirrel monkeys begin to eat solid food around their 2nd month of age, continuing with some nursing until about 11 or 13 months, and were only at this age seen to successfully catch and eat insects. Thus, as infant squirrel monkeys proved to be able to catch and eat insects before their first experience with conspecifics, an innate basis for this behavior can be assumed.     

Greater Soil Carbon Sequestration under Nitrogen-fixing Trees Compared with <Emphasis Type="Italic">Eucalyptus</Emphasis> Species

Forests with nitrogen-fixing trees (N–fixers) typically accumulate more carbon (C) in soils than similar forests without N–fixing trees. This difference may develop from fundamentally different processes, with either greater accumulation of recently fixed C or reduced decomposition of older soil C. We compared the soil C pools under N–fixers with Eucalyptus (non–N–fixers) at four tropical sites: two sites on Andisol soils in Hawaii and two sites on Vertisol and Entisol soils in Puerto Rico. Using stable carbon isotope techniques, we tracked the loss of the old soil organic C from the previous C₄ land use (SOC₄) and the gain of new soil organic C from the C₃, N–fixer, and non–N–fixer plantations (SOC₃). Soils beneath N–fixing trees sequestered 0.11 ± 0.07 kg m⁻² y⁻¹ (mean ± one standard error) of total soil organic carbon (SOC_T) compared with no change under Eucalyptus (0.00 ± 0.07 kg m⁻² y⁻¹; P = 0.02). About 55% of the greater SOC_T sequestration under the N–fixers resulted from greater retention of old SOC₄, and 45% resulted from greater accretion of new SOC₃. Soil N accretion under the N–fixers explained 62% of the variability of the greater retention of old SOC₄ under the N–fixers. The greater retention of older soil C under N–fixing trees is a novel finding and may be important for strategies that use reforestation or afforestation to offset C emissions. Received 12 March 2001; accepted 5 October 2001.     

Die Wirkung von Ultraschall auf die O2-Aufnahme und die anaerobe CO2-Abgabe von Hefezellen

Ohne ZusammenfassungDie Untersuchungen wurden mit Unterstützung der Deutschen Forschungsgemeinschaft durchgeführt.