Dynamics of Pneumococcal Acquisition and Carriage in Young Adults during Training in Confined Settings in Israel

Background

Outbreaks and sporadic cases of pneumococcal illness occur among young adults in confined settings. Our aim was to characterize pneumococcal acquisition and carriage among healthy young adults in Israel during military training in confined settings.

Methods

During the years 2007–2008, an observational longitudinal study was conducted in three cohorts of healthy soldiers, during a 7-month basic training period. Epidemiological data, oropharyngeal and nasopharyngeal cultures were sampled on 5 occasions: before and 3, 6, 12 and 24 weeks after start of training. Samples were processed within 2–18 hours. Relatedness of isolates was investigated by capsular typing of all isolates and pulsed-field gel electrophoresis to determine acquisition and transmission. Carriage and acquisition patterns were analyzed and multivariable logistic regression analysis was performed to assess the impact of time on acquisition after mixing, controlling for other covariates.

Results

Pneumococci were recovered on 202 of 1872 visits among 742 individuals, including 40 different serotypes. Mean carriage prevalence increased in all visits following training initiation. Acquisition during training was high, as 36.9% of individuals acquired pneumococci at least once during training, and for almost one fourth of the whole population this occurred during the first 6 weeks. Significant clustering was noted. Sharing drinking glass/bottle was found to be a significant and common risk factor for pneumococcal acquisition.

Conclusions

Pneumococcal acquisition is highly frequent when young adults live in close contact in confined settings, especially early after mixing.     

40 years of tissue banking in Estonia

A survey is given of the development of tissue banking in Estonia during40 years, in which we address methods of tissue preservation, application ofpreserved skeletal tissues in orthopaedics as well as issues of clinical andexperimental research in this area. Preparation and use of demineralized andmorselized bone allografts has been significant during the last ten years.Progress of endoprosthetic joint surgery has essentially increased the need forbone transplantation in orthopaedics.     

Respiratory acclimation in Arabidopsis thaliana leaves at low temperature

Acclimation of 25 degrees C-grown Arabidopsis thaliana at 5 degrees C resulted in a marked increase of leaf respiration in darkness (Rd) measured at 5 degrees C. Rd was particularly high in leaves developed at 5 degrees C. Leaf respiration (non-photorespiratory intracellular decarboxylation) in the light (Rl) also increased during cold acclimation, but less so than did Rd. The ratio Rd/Pt (Pt - true photosynthesis) was higher in more acclimated or cold-developed leaves, while the ratio Rl/Pt remained unchanged. In cold-acclimated leaves, Rl did not correlate with 3-phosphoglycerate and pyruvate nor with hexose phosphate pools in the cytosol. Rl in A. thaliana leaves was probably not limited by the substrate during cold acclimation. Under the conditions tested, Rd was more sensitive to low temperature stress than Rl.     

Interaction between photorespiration and respiration in transgenic potato plants with antisense reduction in glycine decarboxylase

Potato (Solanum tuberosum L. cv. Désirée) plants with an antisense reduction in the P-protein of the glycine decarboxylase complex (GDC) were used to study the interaction between respiration and photorespiration. Mitochondria isolated from transgenic plants had a decreased capacity for glycine oxidation and glycine accumulated in the leaves. Malate consumption increased in leaves of GDC deficient plants and the capacity for malate and NADH oxidation increased in isolated mitochondria. A lower level of alternative oxidase protein and decreased partitioning of electrons to the alternative pathway was found in these plants. The adenylate status was altered in protoplasts from transgenic plants, most notably the chloroplastic ATP/ADP ratio increased. The lower capacity for photorespiration in leaves of GDC deficient plants was compensated for by increased respiratory decarboxylations in the light. This is interpreted as a decreased light suppression of the tricarboxylic acid cycle in GDC deficient plants in comparison to wild-type plants. The results support the view that respiratory decarboxylations in the light are restricted at the level of the pyruvate dehydrogenase complex and/or isocitrate dehydrogenase and that this effect is likely to be mediated by mitochondrial photorespiratory products.     

Predicting the cover and richness of intertidal macroalgae in remote areas: a case study in the Antarctic Peninsula

Antarctica is an iconic region for scientific explorations as it is remote and a critical component of the global climate system. Recent climate change causes a dramatic retreat of ice in Antarctica with associated impacts to its coastal ecosystem. These anthropogenic impacts have a potential to increase habitat availability for Antarctic intertidal assemblages. Assessing the extent and ecological consequences of these changes requires us to develop accurate biotic baselines and quantitative predictive tools. In this study, we demonstrated that satellite‐based remote sensing, when used jointly with in situ ground‐truthing and machine learning algorithms, provides a powerful tool to predict the cover and richness of intertidal macroalgae. The salient finding was that the Sentinel‐based remote sensing described a significant proportion of variability in the cover and richness of Antarctic macroalgae. The highest performing models were for macroalgal richness and the cover of green algae as opposed to the model of brown and red algal cover. When expanding the geographical range of the ground‐truthing, even involving only a few sample points, it becomes possible to potentially map other Antarctic intertidal macroalgal habitats and monitor their dynamics. This is a significant milestone as logistical constraints are an integral part of the Antarctic expeditions. The method has also a potential in other remote coastal areas where extensive in situ mapping is not feasible.     

Cold-hardening results in increased activity of enzymes involved in carbon metabolism in leaves of winter rye (Secale cereale L.)

Light- and CO₂-saturated photosynthesis of nonhardened rye (Secale cereale L. cv. Musketeer) was reduced from 18.10 to 7.17 mol O₂·m^–2·s^–1 when leaves were transferred from 20 to 5°C for 30 min. Following cold-hardening at 5°C for ten weeks, photosynthesis recovered to 15.05 mol O₂·m^–2·s^–1,comparable to the nonhardened rate at 20°C. Recovery of photosynthesis was associated with increases in the total activity and activation of enzymes of the photosynthetic carbon-reduction cycle and of sucrose synthesis. The total hexose-phosphate pool increase by 30% and 120% for nonhardened and cold-hardened leaves respectively when measured at 5°C. The large increase in esterified phosphate in coldhardened leaves occurred without a limitation in inorganic phosphate supply. In contrast, the much smaller increase in esterified phosphate in nonhardened leaves was associated with an inhibition of ribulose-1,5-bisphosphate carboxylase/oxygenase and sucrose-phosphate synthase activation. It is suggested that the large increases in hexose phosphates in cold-hardened leaves compensates for the higher substrate threshold concentrations needed for enzyme activation at low temperatures. High substrate concentrations could also compensate for the kinetic limitations imposed by product inhibition from the accumulation of sucrose at 5°C. Nonhardened leaves appear to be unable to compensate in this fashion due to an inadequate supply of inorganic phosphate.Abbreviations DHAP dihydroxyacetone phosphate - Fru6P fructose-6-phosphate - Fru 1,6BP fructose-1,6-bisphosphate - Fru1,6BPase fructose-1,6-bisphosphatase - Glc6P glucose-6-phosphate - PGA 3-phosphoglycerate - PPFD photosynthetic photon flux density - CH cold-hardened rye grown at 5°C - NH nonhardened rye grown at 24°C - Rubisco ribulose-1,5-bisphosphate carboxylase/oxygenase - RuBP ribulose-1,5-bisphosphate - SPS sucrose-phosphate synthase - UDPGlc uridine 5-diphosphoglucose This work was supported by operating grants from the Swedish Natural Sciences Research Council to G.Ö. and P.G.     

Oviposition site selection of the Alcon blue butterfly at the northern range margin

Female oviposition decisions in insects may strongly affect offspring growth and survival, and thus determine population performance. In this study, we examined oviposition site selection in the xerophilous ecotype of the endangered myrmecophilous butterfly Phengaris (=Maculinea) alcon (Lepidoptera, Lycaenidae) in Estonia, at the northern distribution margin of both the butterfly and its host plant, Gentiana cruciata L. Egg distribution on individual host plants appeared to be highly uneven: plants carrying high egg loads contrasted to a high proportion of host plants without any or with a few eggs. Host plant use for oviposition was strongly dependent on plant characteristics and environmental context. Host plant height relative to the surrounding vegetation rather than the absolute height of host plants was a key factor determining the use of particular host plant individuals for oviposition. In particular, plants protruding above surrounding vegetation had a higher probability of being used for oviposition, and carried more eggs. Additionally, the number of eggs laid on individual host plants was positively associated with the presence of flowers and the number of shoots. More aggregated host plants received fewer eggs than those with less conspecifics around. Feeding damage by wild herbivores, found in a substantial proportion of the butterfly’s host plants, strongly reduced the number of eggs on individual plants. Our results underline the need to assure that butterfly’s host plants do not become overgrown by surrounding vegetation. Best practices for opening vegetation around host plants may need further studies that explicitly account for butterfly’s host ants—their abundance in relation to vegetation height and their response to opening vegetation.     

Proximate causes of Rensch's rule: does sexual size dimorphism in arthropods result from sex differences in development time?

A prominent interspecific pattern of sexual size dimorphism (SSD) is Rensch's rule, according to which male body size is more variable or evolutionarily divergent than female body size. Assuming equal growth rates of males and females, SSD would be entirely mediated, and Rensch's rule proximately caused, by sexual differences in development times, or sexual bimaturism (SBM), with the larger sex developing for a proportionately longer time. Only a subset of the seven arthropod groups investigated in this study exhibits Rensch's rule. Furthermore, we found only a weak positive relationship between SSD and SBM overall, suggesting that growth rate differences between the sexes are more important than development time differences in proximately mediating SSD in a wide but by no means comprehensive range of arthropod taxa. Except when protandry is of selective advantage (as in many butterflies, Hymenoptera, and spiders), male development time was equal to (in water striders and beetles) or even longer than (in drosophilid and sepsid flies) that of females. Because all taxa show female-biased SSD, this implies faster growth of females in general, a pattern markedly different from that of primates and birds (analyzed here for comparison). We discuss three potential explanations for this pattern based on life-history trade-offs and sexual selection.     

Influence of cultivation method on root grafting in Norway spruce (Picea abies (L.) Karst.)

Root grafting is the process by which a functional union of two or more roots subsequent to their formation is formed. The above- and below-ground parts of three Norway spruce stands (natural stand, Umbric Luvisol; row-culture and group-culture, Planosol; stand ages 40, 43 and 43, respectively) of high site quality (I) were investigated. Stand densities were 1550, 1783 and 1722 stems ha^-1, respectively. In all investigated stands, root grafting was most sensitive to tree spacing. Grafts were observed in case the distance between the trees was 0.7–1.2 m. Grafts occurred always in areas of higher rooting density, in a row of the row-culture and within a tree group in the group-culture. Root grafting was enhanced in case of a narrower humus horizon in the group culture compared with the row-culture, 16.5 and 30 cm, respectively; the humus horizon contained 99% and 95% of conducting roots with d ≥ 5 mm, respectively. Root graftings occurred in 75% of excavated trees in the group-culture, in 37.5% of excavated trees in the row-culture and in 33.3% of excavated trees in the natural stand. Stand age was 24 years in the row-culture and 22 years in the group-culture at the beginning of root grafting. No grafts occurred between two suppressed trees, whereas in 86–100% of all cases, at least one tree was dominant or codominant. In row- and group-cultivated Norway spruce stands, the initial minimum diameter of the grafted root without bark was from 1 to 3 cm in 63% of cases. Grafting of roots with d < 1 cm or d > 10 cm was rare or absent. Root grafting had usually begun at the root age of 10–20 years (46% of cases). This revised version was published online in June 2006 with corrections to the Cover Date.     

Global Displacement of Canine Parvovirus by a Host-Adapted Variant: Structural Comparison between Pandemic Viruses with Distinct Host Ranges

Canine parvovirus type 2 (CPV-2) emerged in 1978 and spread worldwide within 2 years. Subsequently, CPV-2 was completely replaced by the variant CPV-2a, which is characterized by four specific capsid (VP2) mutations. The X-ray crystal structure of the CPV-2a capsid shows that each mutation confers small local changes. The loss of a hydrogen bond and introduction of a glycine residue likely introduce flexibility to sites that control interactions with the host receptor, antibodies, and sialic acids.