The weak effects of climatic change on Plantago pollen concentration: 17 years of monitoring in Northwestern Spain

Plantago L. species are very common in nitrified areas such as roadsides and their pollen is a major cause of pollinosis in temperate regions. In this study, we sampled airborne pollen grains in the city of León (NW, Spain) from January 1995 to December 2011, by using a Burkard® 7-day-recording trap. The percentage of Plantago pollen compared to the total pollen count ranged from 11 % (1997) to 3 % (2006) in the period under study. Peak pollen concentrations were recorded in May and June. Our 17-year analysis failed to disclose significant changes in the seasonal trend of plantain pollen concentration. In addition, there were no important changes in the start dates of pollen release and the meteorological parameters analyzed did not show significant variations in their usual trends. We analyzed the influence of several meteorological parameters on Plantago pollen concentration to explain the differences in pollen concentration trends during the study. Our results show that temperature, sun hours, evaporation, and relative humidity are the meteorological parameters best correlated to the behavior of Plantago pollen grains. In general, the years with low pollen concentrations correspond to the years with less precipitation or higher temperatures. We calculated the approximate Plantago flowering dates using the cumulative sum of daily maximum temperatures and compared them with the real bloom dates. The differences obtained were 4 days in 2009, 3 days in 2010, and 1 day in 2011 considering the complete period of pollination.     

Different contribution of conserved amino acids to the global properties of triosephosphate isomerases

It is generally assumed that the amino acids that exist in all homologous enzymes correspond to residues that participate in catalysis, or that are essential for folding and stability. Although this holds for catalytic residues, the function of conserved noncatalytic residues is not clear. It is not known if such residues are of equal importance and have the same role in different homologous enzymes. In humans, the E104D mutation in triosephosphate isomerase (TIM) is the most frequent mutation in the autosomal diseases named “TPI deficiencies.” We explored if the E104D mutation has the same impact in TIMs from four different organisms (Homo sapiens, Giardia lamblia, Trypanosoma cruzi, and T. brucei). The catalytic properties were not significantly affected by the mutation, but it affected the rate and extent of formation of active dimers from unfolded monomers differently. Scanning calorimetry experiments indicated that the mutation was in all cases destabilizing, but the mutation effect on rates of irreversible denaturation and transition‐state energetics were drastically dependent on the TIM background. For instance, the E104D mutation produce changes in activation energy ranging from 430 kJ mol^?1 in HsTIM to ?78 kJ mol^?1 in TcTIM. Thus, in TIM the role of a conserved noncatalytic residue is drastically dependent on its molecular background. Accordingly, it would seem that because each protein has a particular sequence, and a distinctive set of amino acid interactions, it should be regarded as a unique entity that has evolved for function and stability in the organisms to which it belongs. Proteins 2014; 82:323–335. © 2013 Wiley Periodicals, Inc.     

A novel TctA citrate transporter from an activated sludge metagenome: Structural and mechanistic predictions for the TTT family

We isolated a putative citrate transporter of the tripartite tricarboxylate transporter (TTT) class from a metagenomic library of activated sludge from a sewage treatment plant. The transporter, dubbed TctA_ar, shares ～50% sequence identity with TctA of Comamonas testosteroni (TctA_ct) and other β‐Proteobacteria, and contains two 20‐amino acid repeat signature sequences, considered a hallmark of this particular transporter class. The structures for both TctA_ar and TctA_ct were modeled with I‐TASSER and two possible structures for this transporter family were proposed. Docking assays with citrate resulted in the corresponding sets of proposed critical residues for function. These models suggest functions for the 20‐amino acid repeats in the context of the two different architectures. This constitutes the first attempt at structure modeling of the TTT family, to the best of our knowledge, and could aid functional understanding of this little‐studied family. Proteins 2014; 82:1756–1764. © 2014 Wiley Periodicals, Inc.     

Structural integrity affects nitrogen removal activity of granules in semi-continuous reactors

Granules were observed after more than two years of operation in two semi-continuously fed intermittently aerated reactors treating swine wastewater with aerobic:anoxic cycles of 1:1 h and 1:4 h. Subsequently, the granules and flocs were compared with respect to physical characteristics, activity, and microbial community structure. Granules exhibited higher specific nitrification and denitrification rates than flocs. However, once granule structural integrity was disrupted, the rates decreased to levels similar to those of flocs. Membrane hybridizations using 16S rRNA-targeted probes showed that ammonia oxidizing bacteria populations in flocs and granules were dominated by Nitrosomonas and Nitrosococcus mobilis. Granules provided better conditions for Nitrospira compared to flocs. The diversities of the dominant bacterial populations in granules and flocs were not significantly different. Our findings highlight the importance of structural integrity of granules to their nitrogen removing activity.     

Molecular mechanism of sphingosine-1-phosphate action in Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a lethal muscle-wasting disease. Studies in Drosophila showed that genetic increase of the levels of the bioactive sphingolipid sphingosine-1-phosphate (S1P) or delivery of 2-acetyl-5-tetrahydroxybutyl imidazole (THI), an S1P lyase inhibitor, suppresses dystrophic muscle degeneration. In the dystrophic mouse (mdx), upregulation of S1P by THI increases regeneration and muscle force. S1P can act as a ligand for S1P receptors and as a histone deacetylase (HDAC) inhibitor. Because Drosophila has no identified S1P receptors and DMD correlates with increased HDAC2 levels, we tested whether S1P action in muscle involves HDAC inhibition. Here we show that beneficial effects of THI treatment in mdx mice correlate with significantly increased nuclear S1P, decreased HDAC activity and increased acetylation of specific histone residues. Importantly, the HDAC2 target microRNA genes miR-29 and miR-1 are significantly upregulated, correlating with the downregulation of the miR-29 target Col1a1 in the diaphragm of THI-treated mdx mice. Further gene expression analysis revealed a significant THI-dependent decrease in inflammatory genes and increase in metabolic genes. Accordingly, S1P levels and functional mitochondrial activity are increased after THI treatment of differentiating C2C12 cells. S1P increases the capacity of the muscle cell to use fatty acids as an energy source, suggesting that THI treatment could be beneficial for the maintenance of energy metabolism in mdx muscles.KEY WORDS: HDAC, S1P, THI, dys, Dystrophin, mdx     

In Vivo High-Resolution 7 Tesla MRI Shows Early and Diffuse Cortical Alterations in CADASIL

Background and Purpose

Recent data suggest that early symptoms may be related to cortex alterations in CADASIL (Cerebral Autosomal-Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy), a monogenic model of cerebral small vessel disease (SVD). The aim of this study was to investigate cortical alterations using both high-resolution T2* acquisitions obtained with 7 Tesla MRI and structural T1 images with 3 Tesla MRI in CADASIL patients with no or only mild symptomatology (modified Rankin’s scale ≤1 and Mini Mental State Examination (MMSE) ≥24).

Methods

Complete reconstructions of the cortex using 7 Tesla T2* acquisitions with 0.7 mm isotropic resolution were obtained in 11 patients (52.1±13.2 years, 36% male) and 24 controls (54.8±11.0 years, 42% male). Seven Tesla T2* within the cortex and cortical thickness and morphology obtained from 3 Tesla images were compared between CADASIL and control subjects using general linear models.

Results

MMSE, brain volume, cortical thickness and global sulcal morphology did not differ between groups. By contrast, T2* measured by 7 Tesla MRI was significantly increased in frontal, parietal, occipital and cingulate cortices in patients after correction for multiple testing. These changes were not related to white matter lesions, lacunes or microhemorrhages in patients having no brain atrophy compared to controls.

Conclusions

Seven Tesla MRI, by contrast to state of the art post-processing of 3 Tesla acquisitions, shows diffuse T2* alterations within the cortical mantle in CADASIL whose origin remains to be determined.