Activation of GSK‐3 disrupts cholinergic homoeostasis in nucleus basalis of Meynert and frontal cortex of rats

The cholinergic impairment is an early marker in Alzheimer's disease (AD), while the mechanisms are not fully understood. We investigated here the effects of glycogen synthase kinse‐3 (GSK‐3) activation on the cholinergic homoeostasis in nucleus basalis of Meynert (NBM) and frontal cortex, the cholinergic enriched regions. We activated GSK‐3 by lateral ventricular infusion of wortmannin (WT) and GF‐109203X (GFX), the inhibitors of phosphoinositol‐3 kinase (PI3‐K) and protein kinase C (PKC), respectively, and significantly decreased the acetylcholine (ACh) level via inhibiting choline acetyl transferase (ChAT) rather than regulating acetylcholinesterase (AChE). Neuronal axonal transport was disrupted and ChAT accumulation occurred in NBM and frontal cortex accompanied with hyperphosphorylation of tau and neurofilaments. Moreover, ChAT expression decreased in NBM attributing to cleavage of nuclear factor‐κB/p100 into p52 for translocation into nucleus to lower ChAT mRNA level. The cholinergic dysfunction could be mimicked by overexpression of GSK‐3 and rescued by simultaneous administration of LiCl or SB216763, inhibitors of GSK‐3. Our data reveal the molecular mechanism that may underlie the cholinergic impairments in AD patients.     

A site in the fourth membrane-associated domain of the N-methyl-D-aspartate receptor regulates desensitization and ion channel gating

The N-methyl-d-aspartate (NMDA) receptor has four membrane-associated domains, three of which are membrane-spanning (M1, M3, and M4) and one of which is a re-entrant pore loop (M2). The M1-M3 domains have been demonstrated to influence the function of the ion channel, but a similar role for the M4 domain has not been reported. We have identified a methionine residue (Met(823)) in the M4 domain of the NR2A subunit that regulates desensitization and ion channel gating. A tryptophan substitution at this site did not alter the EC(50) for glycine or the peak NMDA EC(50) but decreased the steady-state NMDA EC(50) and markedly increased apparent desensitization, mean open time, and peak current density. Results of rapid solution exchange experiments revealed that changes in microscopic desensitization rates and closing rates could account for the changes in macroscopic desensitization, steady-state NMDA EC(50), and current density. Other amino acid substitutions at this site could increase or decrease the rate of desensitization and mean open time of the ion channel. Both mean open time and desensitization were dependent primarily upon the hydrophobic character of the amino acid at the position. These results demonstrate an important role for hydrophobic interactions at Met(823) in regulation of NMDA receptor function.     

Variations in lipophilic and vacuolar flavonoids among European Pulicaria species

Four European Pulicaria species, P. odora, P. paludosa, P. sicula and P. vulgare, were analysed for their surface and vacuolar constituents for comparison with previous data obtained for P. dysenterica. Each species had a distinct flavonoid pattern with notable differences between leaf and inflorescence. 6-Hydroxyflavonols were the major lipophilic components in all of the species and tissues except in the leaves of P. paludosa and P. vulgare, where scutellarein 6-methyl ether was the main constituent. In the leaves of P. sicula a more unusual flavone, 6-hydroxyluteolin 5,6,7,3',4'-pentamethyl ether, was a major component. Pulicaria odora was distinguished by the presence of a series of methylated 6-hydroxykaempferol derivatives including a 3,5,6,7,4'-pentamethyl ether. Quercetagetin hexamethyl ether occurred in both tissues of P. sicula together with the 3,7,3,4'-tetra methyl ether and other quercetagetin derivatives, which were 5-methylated. Quercetagetin 3,7,3'-methyl ether was present in all species except P. odora. Flavonol glucuronides were characteristic vacuolar constituents of all the taxa studied. Two rare glycosides, patuletin and 6-hydroxykaempferol 6-methyl ether 7-glucuronides were identified in the inflorescence of P. odora. Pulicaria vulgaris, a rare plant of southern England, had the vacuolar flavonoid profile most similar to the other more abundant British plant, P. dysenterica.     

Could the recycled yarns substitute for the virgin cotton yarns: a comparative LCA

Purpose

Cotton yarns spun from natural fibers are widely used in the apparel industry. Most of waste cotton goods are now disposed by incineration or landfill, which brings resource and environmental challenges to the society. Using the waste cotton to spin yarns is an alternative way to forward a more sustainable future. In this research, two scenarios for the environmental impacts of yarns spun from corresponding fibers are investigated, including recycled cotton fibers and virgin cotton fibers.

Methods

The life cycle assessment (LCA) has been conducted according to the collected data from on-site investigation of typical production factories. The life cycle for the recycled cotton yarn production is divided into five stages, i.e., raw material acquisition, transportation, breaking, mixing, and spinning. The life cycle of virgin cotton yarn production is been divided into four stages, i.e., raw material acquisition, transportation, mixing, and spinning. The functional unit is 1000 kg produced yarns which are used for weaving into the fabrics. Notable impacts on climate change, fossil depletion, water depletion, and human toxicity were observed.

Results

The life cycle impact assessment (LCIA) results show that environmental impacts of recycled cotton yarns are far less than those of virgin cotton yarns, except for climate change and water depletion. The reason is that the land occupation and irrigation water have great impact on environmental impacts of cotton cultivation. In spinning, the electricity is the key factor whose environmental impacts account for the most in the virgin cotton yarn scenario, while the electricity and water consumptions are the key factors for the recycled cotton yarn scenario in the life cycle of yarn production. The sensitivity analysis indicates that improving energy efficiency can significantly reduce environmental burdens for both the two scenarios. The uncertainty distribution of water depletion, human toxicity, fossil depletion, and climate change of the two scenarios were determined with a 90% confidence interval.

Conclusions

The LCIA results reveal recycled cotton yarn is a viable alternative to relieve resource and environmental pressure. About 0.5 ha of agricultural land can be saved, 6600 kg CO₂ eq can be reduced, and 2783 m³ irrigation water can be saved by using 1000 kg of the recycled cotton yarns. It can be concluded that the recycled cotton fibers can be served as a substitute for virgin cotton fibers to reduce agricultural land and avoid environmental impacts generated from the cotton planting.

     

Arabidopsis Profilin Isoforms,PRF1 and PRF2 Show Distinctive Binding Activities and Subcellular Distributions

Profilin is an actin-binding protein that shows complex effects on the dynamics of the actin cytoskeleton. There are five profilin isoforms in Arabidopsis thaliana L. However, it is still an open question whether these isoforms are functionally different. In the present study, two profilin isoforms from Arabidopsis, PRF1 and PRF2 were fused with green fuorescent protein （GFP） tag and expressed in Escherichia coil and A. thaliana in order to compare their biochemical properties in vitro and their cellular distributions in vivo. Biochemical analysis revealed that fusion proteins of GFP-PRF1 and GFP-PRF2 can bind to poly-L-proline and G-actin showing remarkable differences. GFP-PRF1 has much higher affinities for both poly-L-proline and G-actin compared with GFP-PRF2. Observations of living cells in stable transgenic A. thaliana lines revealed that 35S：：GFP-PRF1 formed a filamentous network, while 35S：：GFP-PRF2 formed polygonal meshes. Results from the treatment with latrunculin A and a subsequent recovery experiment indicated that filamentous alignment of GFP-PRF1 was likely associated with actin filaments. However, GFP-PRF2 localized to polygonal meshes resembling the endoplasmic reticulum. Our results provide evidence that Arabidopsis profllin isoforms PRF1 and PRF2 have different biochemical affinities for poly-L-proline and G-actin, and show distinctive Iocalizations in living cells. These data suggest that PRF1 and PRF2 are functionally different isoforms.     

Composition and activity of rhizosphere microbial communities associated with healthy and diseased greenhouse tomatoes

Aims

The goal of this study was to investigate the structure and functional potential of microbial communities associated with healthy and diseased tomato rhizospheres.

Methods

Composition changes in the bacterial communities inhabiting the rhizospheric soil and roots of tomato plants were detected using 454 pyrosequencing. Microbial functional diversity was investigated with BIOLOG technology.

Results

There were significant shifts in the microbial composition of diseased samples compared with healthy samples, which had the highest bacterial diversity. The predominant phylum in both diseased and healthy samples was Proteobacteria, which accounted for 35.7–97.4 % of species. The class Gammaproteobacteria was more abundant in healthy than in diseased samples, while the Alphaproteobacteria and Betaproteobacteria were more abundant in diseased samples. The proportions of pathogenic Ralstonia solanacearum and Actinobacteria species were also elevated in diseased samples. The proportions of the various bacterial populations showed a similar trend both in rhizosphere soil and plant roots in diseased versus disease-free samples, indicating that pathogen infection altered the composition of bacterial communities in both plant and soil samples. In terms of microbial activity, functional diversity was suppressed in diseased soil samples. Soil enzyme activity, including urease, alkaline phosphatase and catalase activity, also declined.

Conclusions

This is the first report that provides evidence that R. solanacearum infection elicits shifts in the composition and functional potential of microbial communities in a continuous-cropping tomato operation.     

Pregnancy Rates in Repeat-breeder Heifers Following Multiple Artificial Inseminations during Spontaneous Oestrus

Hormonal asynchronies during oestrus, related to the presence of suprabasal plasma-progesterone (P4) concentrations and a delayed ovulation, interfere with the fertility of repeat-breeder heifers (RBH). Since tubal dysfunction can occur in connection with hormonal asynchronies and constrained availability of fertile spermatozoa at the time of ovulation, the present study tested the hypothesis that frequent sperm deposition from onset of oestrus to ovulation may improve pregnancy rates in RBH. Five RBH and five virgin heifers (VH; controls) were repeatedly artificially inseminated (AI) at 6 h intervals from onset of oestrus to spontaneous ovulation. Hormone analyses revealed suprabasal P₄ concentrations and a delay in the occurrence of the luteinising hormone (LH) surge, but a normal cortisol profile in RBH. Compared with controls, RBH presented longer interval from onset of oestrus to ovulation, and therefore, received more AIs. Pregnancy rates in RBH reached control levels (60%; NS), indicating that the hypothesis might be correct. Pregnancy rates in VH were below the expected range, presumably attributed to a deleterious influence of the frequent handling. The study suggests that pregnancy rates can be improved in RBH by frequent AI in relation to spontaneous ovulation. However, this practice of repeated manipulations, while seeming not to show adverse effects, lacks practicality for routine use.     

Cliques in mitotic spindle network bring kinetochore‐associated complexes to form dependence pathway

The mitotic spindle is an essential molecular machine for chromosome segregation during mitosis. Achieving a better understanding of its organization at the topological level remains a daunting task. To determine the functional connections among 137 mitotic spindle proteins, a protein–protein interaction network among queries was constructed. Many hub proteins, which connect more than one query and serve as highly plausible candidates for expanding the mitotic spindle proteome, are ranked by conventional degree centrality and a new subnetwork specificity score. Evaluation of the ranking results by literature reviews and empirical verification of SEPT6, a novel top‐ranked hub, suggests that the subnetwork specificity score could enrich for putative spindle‐related proteins. Topological analysis of this expanded network shows the presence of 30 3‐cliques and six 4‐cliques (fully connected subgraphs) that, respectively, reside in eight kinetochore‐associated complexes, of which seven are evolution conserved. Notably, these complexes strikingly form dependence pathways for the assembly of the kinetochore complex. These analyses indicate the feasibility of using network topology, i.e. cliques, to uncover novel pathways to accelerate our understanding of potential biological processes.