Needle δ13C and mobile carbohydrates in Pinus koraiensis in relation to decreased temperature and increased moisture along an elevational gradient in NE China

A tree’s crown interacts with atmospheric variables such as CO₂, temperature, and humidity. Physioecology of leaves/needles (e.g. δ¹³C, mobile carbohydrates, and nitrogen) is, therefore, strongly affected by microclimate in and surrounding a tree crown. To understand the physiological responses of leaves to changes in air temperature and moisture, we measured δ¹³C, soluble sugars, starch, and total nitrogen (N) concentrations in current year and 1-yr-old needles of Pinus koraiensis trees, and compared the growing season air temperature and relative humidity within and outside P. koraiensis crowns along an elevational gradient from 760 to 1,420 m a.s.l. on Changbai Mountain, NE China. Our results indicated that needle N and mobile carbohydrates concentrations, as well as needle δ¹³C values changed continuously with increasing elevation, corresponding to a continuous decrease in air temperature and an increase in relative humidity. Needle carbon and nitrogen status is highly significantly negatively correlated with temperature, but positively correlated with relative humidity. These results indicate that increases in air temperature in combination with decreases in relative humidity may result in lower levels of N and mobile carbohydrates in P. koraiensis trees, suggesting that future climate changes such as global warming and changes in precipitation patterns will directly influence the N and carbon physiology at P. koraiensis individual level, and indirectly affect the competitive ability, species composition, productivity and functioning at the stand and ecosystem level in NE China. Due to the relatively limited range of the transect (760–1,420 m) studied, further research is needed to explain whether the present results are applicable to scales across large elevational gradients.     

Investigation on bioactive protection of the amino acids derived from LEA protein on insulin by molecular simulation

Nowadays heat-sensitive protein medicines are increasingly showing their importance in the treatment of various diseases. Their popularisation and application are meeting a great challenge because of their heat lability. In this study, human insulin as a heat-sensitive protein medicine and 66 amino acids derived from a Group 3 late embryogenesis abundant protein fragment as a complex bioactive protectant, were chosen to be investigated to determine whether these amino acids can be used to protect the insulin from denaturation due to drying. The experiments were carried out by using a replica exchange molecular dynamics (REMD) simulation and GROMACS software with Gromos96 (53a6) force field. The REMD results indicate that those amino acids can effectively prevent the reversal between hydrophilic and hydrophobic surface. Both the configurations and secondary structures of the protected insulin were preserved very well. The H-bonding and electrostatic interactions between the insulin and the protectant play key roles in the bioactive protection of insulin. These results agree well with the water replacement hypothesis. All the results prove that these amino acids are a perfect bioactive protectant for heat-sensitive protein medicines.     

Brain Endogenous Estrogen Levels Determine Responses to Estrogen Replacement Therapy via Regulation of BACE1 and NEP in Female Alzheimer’s Transgenic Mice

Estrogens have been found to improve memory and reduce risk of dementia, although conflicting results such as failure of estrogen replacement therapy for treatment of Alzheimer's disease (AD) also has been reported. Only recently, our published human brain studies showed a depletion of brain estrogen in women with AD, while other studies have demonstrated cognitive impairment believed to be caused by inhibition of endogenous estrogen synthesis in females. To investigate whether the shortage of brain estrogen alters the sensitivity of response to estrogen replacement therapy, we have used genetic and surgical animal models to examine the response of estrogen treatment in AD neuropathology. Our studies have shown that early treatment with 17β-estradiol (E2) or genistein could reduce brain amyloid levels by increasing Aβ clearance in both APP23 mice with genetic deficiency of aromatase (APP/Ar^+/?), in which the brains contain nondetectable levels of estrogen, and in APP23 mice with an ovariectomy (APP/OVX), in which the brains still contain certain levels of estrogen. However, only APP/Ar^+/? mice showed a great reduction in brain amyloid plaque formation after E2 or genistein treatment along with downregulation of β-secretase (BACE1) mRNA and protein expression. Our results suggest that early and long-term usage of E2 and/or genistein may prevent AD pathologies in a dependent manner on endogenous brain estrogen levels in aged females.     

Grape seed proanthocyanidin extracts prevent high glucose-induced endothelia dysfunction via PKC and NF-κB inhibition

In our study, it has been detected in vivo and in vitro that GSPE reversed high glucose-induced the increase of ICAM-1 and VCAM-1. It is shown that by western blotting detection, GSPE significantly inhibited the activation of NF-κB induced by high glucose while there was significant decrease of the expression of PKC with GSPE intervention. By adding the NF-κB blocker PDTC and the PKC inhibitor peptide 19–31(10^?6 M), no significant difference was found in the levels of VCAM-1 and ICAM-1 among GSPE group, the PKC inhibitor peptide 19–31-added GSPE group and the PDTC-added GSPE group. So the conclusion could be drawn that PKC inhibition must be involved in GSPE decreasing the level of ICAM-1 and VCAM-1.We proved for the first time that GSPE prevented high glucose-induced the increase of ICAM-1 and VCAM-1 by PKC and NF-κB inhibition. These findings show a novel mechanism of the action GSPE preventing endothelial dysfunction, which may have clinical application values.     

Fine mapping and candidate gene analysis of LM3, a novel lesion mimic gene in rice

A rice lesion mimic mutant, lm3, was obtained by the mutagenesis of an indica cultivar, 93-11, using γ-ray radiation. Brownish lesions appeared on the leaves of lm3 at the young seedling stage and persisted until the ripening stage. The lm3 mutant was characterised by a shorter plant height and delayed heading compared with the wild-type 93-11. A genetic analysis indicated that the lesion mimic phenotype was controlled by a single recessive gene. Using simple sequence repeat (SSR) markers, the target gene LM3 was first located between marker RM5748 and RM14906 on chromosome 3. We then developed Insertion-Deletion (InDel) markers to fine-map LM3, and the locus was localised to a 29 kb region defined by two InDel markers, In12571 and In12600. Five ORFs were predicted in the candidate region, and DNA sequencing detected a single-nucleotide polymorphism (SNP) in the coding region of LOC Os03g21900. The SNP in the fourth exon (C in 93-11; T in lm3) of LOC_Os03g21900 results in the substitution of a proline (P) with a serine (S) at the 140^th amino acid of the deduced uroporphyrinogen decarboxylase protein. We did not detect polymorphisms in the other predicted ORF regions between lm3 and 93-11. These results suggest that LOC_Os03g21900 is the most likely candidate gene for LM3.     

Single-Molecule Force Spectroscopy Study on the Mechanism of RNA Disassembly in Tobacco Mosaic Virus

To explore the disassembly mechanism of tobacco mosaic virus (TMV), a model system for virus study, during infection, we have used single-molecule force spectroscopy to mimic and follow the process of RNA disassembly from the protein coat of TMV by the replisome (molecular motor) in vivo, under different pH and Ca²⁺ concentrations. Dynamic force spectroscopy revealed the unbinding free-energy landscapes as that at pH 4.7 the disassembly process is dominated by one free-energy barrier, whereas at pH 7.0 the process is dominated by one barrier and that there exists a second barrier. The additional free-energy barrier at longer distance has been attributed to the hindrance of disordered loops within the inner channel of TMV, and the biological function of those protein loops was discussed. The combination of pH increase and Ca²⁺ concentration drop could weaken RNA-protein interactions so much that the molecular motor replisome would be able to pull and disassemble the rest of the genetic RNA from the protein coat in vivo. All these facts provide supporting evidence at the single-molecule level, to our knowledge for the first time, for the cotranslational disassembly mechanism during TMV infection under physiological conditions.