Synthesis, biological evaluation, and modeling studies of inhibitors aimed at the malarial proteases plasmepsins I and II

The increasing resistance of the malarial parasite to antimalarial drugs is a major contributor to the reemergence of the disease and increases the need for new drug targets. The two aspartic proteases, plasmepsins I and II, from Plasmodium falciparum have recently emerged as potential targets. In an effort to inhibit these hemoglobinases, a series of inhibitors encompassing a basic hydroxyethylamine transition state isostere as a central fragment were prepared. The synthesized compounds were varied in the P1' position and exhibited biological activities in the range of 31 to >2000 nM. To try to rationalize the results, molecular docking and 3D-QSAR analysis were used.     

Function and dynamics of auxin and carbohydrates during earlywood/latewood transition in scots pine

In temperate regions the annual pattern of wood development is characterized by the formation of radially narrow and thick walled latewood cells. This takes place at the later part of the growing season when cambial cell division declines. To gain new insight into the regulation of this process, micro-analytical techniques were used to visualize the distribution of indole-3-acetic acid (IAA), soluble carbohydrates, and activities of sucrose (Suc)-metabolizing enzymes across the cambial region tissues in Scots pine (Pinus sylvestris). The total amount of IAA in the cambial region did not change with latewood initiation. But its radial distribution pattern was altered, resulting in an increased concentration in the cambial meristem and its recent derivatives. Thus, initiation of latewood formation and cessation of cambial cell division is not a consequence of decreased IAA concentrations in dividing and expanding cells. Rather, IAA most likely has a role in defining the altered developmental pattern associated with latewood formation. Carbohydrates and enzyme activities showed distinctive radial distribution patterns. Suc peaked in the phloem and decreased sharply to low levels across the cambial zone, whereas fructose and glucose reached their highest levels in the maturing tracheids. Suc synthase was the dominating Suc cleaving enzyme with a peak in the secondary wall-forming tracheids and in the phloem. Soluble acid invertase peaked in dividing and expanding cells. Suc-phosphate synthase had its highest activities in the phloem. Activities of cell wall bound invertase were low. The absence of major seasonal variations indicates that carbohydrate availability is not a trigger for latewood initiation. However, steep concentration gradients of the sugars suggest a role for sugar signaling in vascular development.     

Impact of Ten-Valent Pneumococcal Conjugate Vaccination on Invasive Pneumococcal Disease in Finnish Children – A Population-Based Study

Background

The ten-valent pneumococcal conjugate vaccine (PCV10) was introduced into the Finnish National Vaccination Program (NVP) in September 2010 with a 2+1 schedule (3, 5, 12 months) without catch-up vaccinations. We evaluated the direct and indirect effects of PCV10 on invasive pneumococcal disease (IPD) among children ≤5 years of age during the first three years after NVP introduction.

Methods

We conducted a population-based, observational follow-up study. The cohort of vaccine-eligible children (all children born June 1, 2010 or later) was followed from 3 months of age until the end of 2013. For the indirect effect, another cohort of older children ineligible for PCV10 vaccination was followed from 2011 through 2013. Both cohorts were compared with season- and age-matched reference cohorts before NVP introduction. National, population-based laboratory surveillance data were used to compare culture-confirmed serotype-specific IPD rates in the vaccine target and reference cohorts by using Poisson regression models.

Results

The overall IPD rate among vaccine-eligible children was reduced by 80% (95%CI 72 to 85); the reduction in vaccine-type IPD was 92% (95%CI 86 to 95). However, a non-significant increase in non-vaccine type IPD was observed. During 2012–2013, we also observed a 48% (95%CI 18 to 69) reduction in IPD among unvaccinated children 2 to 5 years of age, which was mostly attributable to the ten vaccine serotypes.

Conclusions

This is the first population-based study investigating the impact of PCV10 introduction without prior PCV7 use. A substantial decrease in IPD rates among vaccine-eligible children was observed. A smaller and temporally delayed reduction among older, unvaccinated children suggests that PCV10 also provides indirect protection against vaccine-type IPD. Changes in serotype distribution warrant continuous monitoring of potential increases in non-vaccine serotypes.     

Investigation of lymphotoxin α genetic variants in migraine

Migraine is a common neurological disease with a genetic basis affecting approximately 12% of the population. Pain during a migraine attack is associated with activation of the trigeminal nerve system, which carries pain signals from the meninges and the blood vessels infusing the meninges to the trigeminal nucleus in the brain stem. The release of inflammatory mediators following cortical spreading depression (CSD) may further promote and sustain the activation and sensitization of meningeal nociceptors, inducing the persistent throbbing headache characterised in migraine. Lymphotoxin α (LTA) is a cytokine secreted by lymphocytes and is a member of the tumour necrosis factor (TNF) family. Genetic variation with the TNF and LTA genes may contribute to threshold brain excitability, propagation of neuronal hyperexcitability and thus initiation and maintenance of a migraine attack. Three LTA variants rs2009658, rs2844482 and rs2229094 were identified in a recent pGWAS study conducted in the Norfolk Island population as being potentially implicated in migraine with nominally significant p values of p = 0.0093, p = 0.0088 and p = 0.033 respectively. To determine whether these SNPs played a role in migraine in a general outbred population these SNPs were gentoyped in a large case control Australian Caucasian population and tested for association with migraine. All three SNPs showed no association in our cohort (p > 0.05). Validation of GWAS data in independent case-controls cohorts is essential to establish risk validity within specific population groups. The importance of cytokines in modulating neural inflammation and pain threshold in addition to other studies showing associations between TNF-α and SNPs in the LTA gene with migraine, suggests that LTA could be an important factor contributing to migraine. Although the present study did not support a role for the tested LTA variants in migraine, investigation of other variants within the LTA gene is still warranted.     

Activation of Auditory Cortex by Anticipating and Hearing Emotional Sounds: An MEG Study

To study how auditory cortical processing is affected by anticipating and hearing of long emotional sounds, we recorded auditory evoked magnetic fields with a whole-scalp MEG device from 15 healthy adults who were listening to emotional or neutral sounds. Pleasant, unpleasant, or neutral sounds, each lasting for 6 s, were played in a random order, preceded by 100-ms cue tones (0.5, 1, or 2 kHz) 2 s before the onset of the sound. The cue tones, indicating the valence of the upcoming emotional sounds, evoked typical transient N100m responses in the auditory cortex. During the rest of the anticipation period (until the beginning of the emotional sound), auditory cortices of both hemispheres generated slow shifts of the same polarity as N100m. During anticipation, the relative strengths of the auditory-cortex signals depended on the upcoming sound: towards the end of the anticipation period the activity became stronger when the subject was anticipating emotional rather than neutral sounds. During the actual emotional and neutral sounds, sustained fields were predominant in the left hemisphere for all sounds. The measured DC MEG signals during both anticipation and hearing of emotional sounds implied that following the cue that indicates the valence of the upcoming sound, the auditory-cortex activity is modulated by the upcoming sound category during the anticipation period.     

The testosterone binding mechanism of an antibody derived from a naïve human scFv library

A testosterone binding scFv antibody was isolated from a naïve human library with a modest size of 10⁸ clones. The crystal structure of the Fab fragment form of the 5F2 antibody clone complexed with testosterone determined at 1.5 Å resolution shows that the hapten is bound deeply in the antibody binding pocket. In addition to the interactions with framework residues only CDR‐L3 and CDR‐H3 loops interact with testosterone and the heavy chain forms the majority of the contacts with the hapten. The testosterone binding site of the 5F2 antibody with a high abundance of aromatic amino acid residues shows similarity with an in vitro affinity matured antibody having around 300 times higher affinity. The moderate affinity of the 5F2 antibody originates from the different orientation of the hapten and few light chain contacts. This is the first three‐dimensional structure of a human steroid hormone binding antibody that has been isolated from a naïve human repertoire. Copyright © 2010 John Wiley & Sons, Ltd.     

Long-term warming effects on root morphology, root mass distribution, and microbial activity in two dry tundra plant communities in northern Sweden

Effects of warming on root morphology, root mass distribution and microbial activity were studied in organic and mineral soil layers in two alpine ecosystems over>10 yr, using open-top chambers, in Swedish Lapland. Root mass was estimated using soil cores. Washed roots were scanned and sorted into four diameter classes, for which variables including root mass (g dry matter (g DM) m(-2)), root length density (RLD; cm cm(-3) soil), specific root length (SRL; m g DM(-1)), specific root area (SRA; m2 kg DM(-1)), and number of root tips m(-2) were determined. Nitrification (NEA) and denitrification enzyme activity (DEA) in the top 10 cm of soil were measured. Soil warming shifted the rooting zone towards the upper soil organic layer in both plant communities. In the dry heath, warming increased SRL and SRA of the finest roots in both soil layers, whereas the dry meadow was unaffected. Neither NEA nor DEA exhibited differences attributable to warming. Tundra plants may respond to climate change by altering their root morphology and mass while microbial activity may be unaffected. This suggests that carbon may be incorporated in tundra soils partly as a result of increases in the mass of the finer roots if temperatures rise.     

Archaeal diversity and community structure in a Swedish barley field: Specificity of the EK510R/(EURY498) 16S rDNA primer

The aim of this study was to analyze a total euryarchaeal community at DNA and RNA levels in a Swedish barley field with relation to soil depth (0-10 and 20-30 cm layers), soil fraction (bulk soil and rhizosphere) and time (August and November sample collection). Amplification of 16S rRNA gene using the archaeal universal A2F and Euryarchaea specific EK510R/(EURY498) primer pair, combined with denaturing gradient gel electrophoresis (DGGE), revealed distinct differences between rDNA and rRNA DGGE profiles. The soil depth, time, or rhizosphere effects did not significantly influence Archaeal community structure. Surprisingly, sequence analysis of DGGE-derived amplicons revealed the presence of Euryarchaea as well as uncultured soil Crenarchaea affiliated with group 1. In agreement, sequence comparison analyses showed that the majority of uncultured Crenarchaea group 1 had almost 100% sequence complementarity to the 3' end of the EK510R/(EURY498) primer. Therefore, we propose that EK510R/(EURY498R) is a universal archaeal primer rather than a Euryarchaea specific SSUrRNA primer. Hence, considerable care should be taken during application of this primer in studies of euryarchaeal biodiversity in soil environments.