Mitochondrial haplotypes may modulate the phenotypic manifestation of the LHON-associated m.14484T>C (MT-ND6) mutation in Chinese families

Mitochondrial m.14484T>C (MT-ND6) mutation has been associated with Leber's hereditary optic neuropathy. Previous investigations revealed that the m.14484T>C mutation is a primary factor underlying the development of optic neuropathy but is not sufficient to produce a clinical phenotype. However, mitochondrial haplogroups have been proposed to modulate the phenotypic manifestation of the m.14484T>C mutation. Here, we performed the clinical, genetic evaluation and complete mitochondrial genome sequence analysis of 41 Han Chinese pedigrees carrying the m.14484T>C mutation. These families exhibited a wide range of penetrances and expressivities of optic neuropathy. The average ratio between affected male/female matrilineal relatives from 41 families was 2:1. The penetrance of optic neuropathy in these Chinese pedigrees ranged from 5.6% to 100%, with the average of 23.8%. Furthermore, the age-of-onset for optic neuropathy varied from 4 to 44 years, with the average of 19.3 years. Sequence analysis of their mitochondrial genomes identified distinct sets of polymorphisms belonging to ten Eastern Asian haplogroups, indicating that the m.14484T>C mutation occurred through recurrent origins and founder events. We showed that mitochondrial haplogroups M9, M10 and N9 increased the penetrance of optic neuropathy in these Chinese families. In particular, these mitochondrial haplogroup specific variants: m.3394T>C (MT-ND1), m.14502T>C (MT-ND4) and m.14693A>G (MT-TE) enhanced the penetrance of visual loss in these Chinese families. These data provided the direct evidence that mitochondrial modifiers modulate the variable penetrance and expressivity of optic neuropathy among Chinese pedigrees carrying the m.14484T>C mutation.     

Potential Impact of Influenza A/H1N1 Pandemic and Hand-Gels on Acute Diarrhea Epidemic in France

Background

The 2009 A/H1N1 influenza pandemic has received a great deal of attention from public health authorities. Our study examines whether this pandemic and the resulting public health measures could have impacted acute diarrhea, a prevalent, highly transmissible and historically monitored disease.

Methods

Using augmentation procedures of national data for the previous five years (2004–2009), we estimated the expected timing and incidence of acute diarrhea in France in 2009–2010 and evaluated differences with the observed. We also reviewed national hand gels for the same period.

Findings

Number of episodes of acute diarrhea in France in 2009–2010 was significantly lower than expected until the third week of December (−24%, 95% CI [−36%; −9%]), then significantly higher (+40%, 95% CI [22%; 62%]), leading to a surplus of 574,440 episodes. The epidemic was delayed by 5 weeks with a peak 1.3 times higher than expected. Hand-gels sales inversely correlated with incidence of both influenza-like illness and acute diarrheal disease. Among individuals >65 yo, no excess cases of influenza and no excess rebound in acute diarrhea were observed, despite similar delay in the onset of the seasonal diarrheal epidemic.

Interpretation

Our results suggest that at least one endemic disease had an unexpected behavior in 2009–2010. Acute diarrhea seems to have been controlled during the beginning of the pandemic in all age groups, but later peaked higher than expected in the younger population. The all-age delay in seasonal onset seems partly attributable to hand-gels use, while the differential magnitude of the seasonal epidemic between young and old, concurrent for both influenza and acute diarrhea, is compatible with disease interaction.     

Overexpression of the mango MiCO gene delayed flowering time in transgenic Arabidopsis

Plant Cell, Tissue and Organ Culture (PCTOC) - CONSTANS (CO)/CONSTANS-like (COL) genes play an important role in the photoperiodic flowering pathway. However, the functional roles of the CO/COL...     

The Force-Biased Algorithm for the Irregular Close Packing of Equal Hard Spheres

Abstract

We present a “force-biased” algorithm for generating the irregular close packing of hard spheres. The algorithm is partly based on Jodrey and Tory's ideas [9] and incorporates methods from Molecular Dynamics. Packings generated by means of the two algorithms are consistent up to final packing fraction of 0.65, which seems to be the limit density of Jodrey and Tory's method. Significantly higher densities (up to 0.71) can be achieved for small numbers of spheres by the force-biased algorithm. However the shape of the radial and angle distribution functions implies that a partial short-range ordering occurs in packings of those densities.     

Degradation kinetics of biochar from pyrolysis and hydrothermal carbonization in temperate soils

Background and Aims

Estimates of biochar residence times in soils range over three orders of magnitude. We present the first direct comparison between the biodegradation of a char from hydrothermal carbonization (htcBC) and pyrolysis (pyrBC) with high temporal resolution.

Methods

Mineralization of the biochars and their shared Miscanthus feedstock in three soils was determined directly by the ¹³CO₂ efflux using a novel method incorporating wavelength scanned cavity ring-down spectroscopy. Biochar half-life (t_1/2) was estimated with three empirical models.

Results

(1) The htcBC was readily biodegradable, whereas pyrBC was more recalcitrant. (2) Cumulative degradation of both biochars increased with soil organic carbon and nitrogen content. (3) The corrected Akaike information criterion (AIC_C) showed an overall preference for the double exponential model (DEM) reflecting a labile and a recalcitrant C-pool, over the first-order degradation model (FODM) and a logarithmic model. (4) The DEM resulted in t_1/2 ranging from 19.7–44.5, 0.7–2.1 and 0.8–1.3 years for pyrBC, htcBC and feedstock, respectively.

Conclusion

The degradation was rather similar between feedstock and htcBC but one order of magnitude slower for pyrBC. The AIC_C preferred FODM in two cases, where the DEM parameters indicated no distinction between a labile and recalcitrant carbon pool.