Effects of sex and estrous cycle on the brain and plasma arginine metabolic profile in rats

l-arginine is a versatile amino acid with a number of bioactive metabolites. Increasing evidence implicates altered arginine metabolism in the aging and neurodegenerative processes. The present study, for the first time, determined the effects of sex and estrous cycle on the brain and blood (plasma) arginine metabolic profile in naïve rats. Female rats displayed significantly lower levels of l-arginine in the frontal cortex and three sub-regions of the hippocampus when compared to male rats. Moreover, female rats had significantly higher levels of l-arginine and γ-aminobutyric acid, but lower levels of l-ornithine, agmatine and putrescine, in plasma relative to male rats. The observed sex difference in brain l-arginine appeared to be independent of the enzymes involved in its metabolism, de novo synthesis and blood-to-brain transport (cationic acid transporter 1 protein expression at least), as well as circulating l-arginine. While the estrous cycle did not affect l-arginine and its metabolites in the brain, there were estrous cycle phase-dependent changes in plasma l-arginine. These findings demonstrate the sex difference in brain l-arginine in the estrous cycle-independent manner. Since peripheral blood has been increasingly used to identify biomarkers of brain pathology, the influences of sex and estrous cycle on blood arginine metabolic profile need attention when experimental research involves female rodents.

     

SENP3 senses oxidative stress to facilitate STING-dependent dendritic cell antitumor function

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The homochiral metallosupramolecular column structure of rhenium (I) complex

The chiral construction of complex supramolecular systems is receiving much interest, especially with achiral building units. In this paper, we reported the helix supramolecular structure of an achiral rhenium complex crystal, [Re(CO)₃(C₁₆H₁₂N₂)(MeCN)] · ClO₄, which was formed by coordination of Re(CO)₅Cl with 2-methenepyridyl-1-aminonaphthalene and acetonitrile. X-ray diffraction analysis suggests that homohelical column metallosupramolecular architecture results from the array of the six-coordinated Re around and along a line: the helical axis in chiral P1211 (No. 4) space group. There is rare example of constructing helical architectures with both coordinated and hydrogen bonds from achiral units. The helical self-assembly process is induced by the intrastrand interaction and crystal growth. Here, the perchlorate acts as both the counter ion and the bridge linking the neighboring coordinated parts together by weak non-covalent interaction. Furthermore, the two-dimensional arrangement adopts double-edged axe-shaped motif, which is different from the common herringbone or brick-wall pattern in coordination polymers. Our investigation introduced the special arrangement model into complicated helical architecture, especially homochiral single-colony.     

Ischemia impairs the association between connexin 43 and M3 subtype of acetylcholine muscarinic receptor (M3-mAChR) in ventricular myocytes.

We used Western blot analysis to examine the expression of connexin 43 and M2/M3 acetylcholine muscarinic receptors (mAChR) and their interaction in ventricular myocytes from control and the ischemic heart. We confirmed that the connexin 43 and M2/ M3-mAChR were expressed in ventricular myocytes. Moreover, we showed that M3-mAChR was expressed in non-glycosylated (72 kDa) and glycosylated forms (115 kDa). Immunostaining showed that connexin 43 is closely associated with M3-mAChR in parts of cell membranes of myocytes. Immunoprecipitation of lysate of cardiac myocytes with M2/M3-mAChR antibody pulled down a 44 kDa protein recognized by connexin 43 antibody. Ischemia increased the expression of M3-mAChR in myocytes. The ischemiainduced increase in the M3-mAChR expression was specific because ischemia did not affect the expression of M1, M2, M4 and M5- mAChR in the heart. On the other hand, ischemia decreased the expression of connexin 43 in myocardium. We also examined the effect of ischemia on the interaction between M2/M3-mAChR and connexin 43. Ischemia suppressed the association of M3-mAChR with connexin 43 but did not affect the association of connexin 43 with M2-mAChR. Administration of choline before ischemia not only partially restored the expression of connexin 43 but also attenuated the ischemia-induced suppression of the association between connexin 43 and M3-mAChR. We conclude that connexin 43 interacts with M2/M3-mAChR and that ischemia specifically impairs the association between M3-mAChR and connexin 43.     

Sinomenine hydrochloride enhancement of the inhibitory effects of anti-transferrin receptor antibody-dependent on the COX-2 pathway in human hepatoma cells

Transferrin receptor (TfR) has been used as a target for the antibody-based therapy of cancer due to its higher expression in tumors relative to normal tissues. Great potential has been shown by anti-TfR antibodies combined with chemotherapeutic drugs as a possible cancer therapeutic strategy. In our study, we investigated the anti-tumor effects of anti-TfR monoclonal antibody (mAb) alone or in combination with sinomenine hydrochloride in vitro. Results suggested that anti-TfR mAb or sinomenine hydrochloride could induce apoptosis, inhibit proliferation, and affect the cell cycle. A synergistic effect was found in relation to tumor growth inhibition and the induction of apoptosis when anti-TfR mAb and sinomenine hydrochloride were used simultaneously. The expression of COX-2 and VEGF protein in HepG2 cells treated with anti-TfR mAb alone was increased in line with increasing dosage of the agent. In contrast, COX-2 expression was dramatically decreased in HepG2 cells treated with sinomenine hydrochloride alone. Furthermore, we demonstrated that the inhibitory effects of sinomenine hydrochloride and anti-TfR mAb administered in combination were more prominent than when the agents were administered singly. To sum up, these results showed that the combined use of sinomenine hydrochloride and anti-TfR mAb may exert synergistic inhibitory effects on human hepatoma HepG2 cells in a COX-2-dependent manner. This finding provides new insight into how tumor cells overcome the interference of iron intake to survive and forms the basis of a new therapeutic strategy involving the development of anti-TfR mAb combined with sinomenine hydrochloride for liver cancer.     

Three new synonyms of Macromitrium microstomum (Hook. & Grev.) Schwägr. (Bryophyta,Orthotrichaceae), with comments on its morphological variations

Macromitrium filicaule Müll.Hal., M. pacificum var. brevisetum Thér. and M. subnitidum Müll.Hal are placed in synonymy with Macromitrium microstomum (Hook. & Grev.) Schwägr. The morphological variations of M. microstomum branch leaves, perichaetial leaves and capsules are illustrated by digital images.     

An estimation of Canadian population exposure to cosmic rays from air travel

Based on air travel statistics in 1984, it was estimated that less than 4 % of the population dose from cosmic ray exposure would result from air travel. In the present study, cosmic ray doses were calculated for more than 3,000 flights departing from more than 200 Canadian airports using actual flight profiles. Based on currently available air travel statistics, the annual per capita effective dose from air transportation is estimated to be 32 μSv for Canadians, about 10 % of the average cosmic ray dose received at ground level (310 μSv per year).     

Intermediate herbivory intensity of an aboveground pest promotes soil labile resources and microbial biomass via modifying rice growth

Background and Aims

The importance of aboveground herbivores for modifying belowground ecosystems has prompted numerous studies; however, studies can be biased by context dependent conditions which lead to extremely inconsistent results. So far, the impacts of herbivory intensity by important rice pests on rice paddy soil ecosystems are lacking. The aim of this study was to test the hypothesis that intermediate herbivory intensity of the brown planthopper (Nilaparvata lugens Stål) could promote soil labile resources and microbial biomass, while high intensity would show a reverse pattern, by mediating rice plant growth. This study will also help the development of integrative pest management.

Methods

Four hopper infestation density treatments (0, 4, 8 and 12 nymphs per rice plant) and two infestation duration treatments (9 and 15 days after N. lugens infestation, DAI 9 and DAI 15) were established in a glasshouse experiment. Soil and plant were sampled destructively from four replicates and analysed for soil labile resources availability, soil microbial biomass and plant performance, respectively.

Results

The infestation density significantly affected both shoot and root mass of rice (P?<?0.05), soil dissolved organic carbon (DOC) and nitrogen (DON), and microbial biomass carbon (MBC) and nitrogen (MBN), and the effects were further enhanced by prolonged infestation duration. Compared to the control (CK) without N. lugens, plant dry mass, DOC, DON, MBC and MBN increased under low (LD) and moderate hopper densities (MD) but decreased under high density (HD) on DAI 9. Moreover, the LD treatment exerted the most promotional effects on DAI 15. Rice root to shoot ratio generally increased in treatments subjected to herbivory. The labile resources and microbial biomass showed close relationships with both shoot and root mass across treatments, in particular with root mass on DAI 15. Such a trend indicated that the shift of photosynthate allocation to belowground contributed to changes of soil resource availability and microbial biomass.

Conclusions

Intermediate herbivory intensity showed positive effects on rice seedling performance and, further, promoted soil labile resource availability and microbial biomass. The importance of extrapolating temporal and spatial scale, i.e. from the short-term greenhouse experiment to an entire rice growing season in the field, was highlighted.     

Biomass production, relative competitive ability and water use efficiency of two dominant species in semiarid Loess Plateau under different water supply and fertilization treatments

Water stress and nutrient deficiency are considered to be the main environmental factors limiting plant growth and species interaction in semiarid regions. However, less is known about the interactive effects of soil water, nitrogen and phosphorus on native species growth and relative competitive ability. A replacement series design method was used with 12 mixed plants of Bothriochloa ischaemum and Lespedeza davurica grown in a pot experiment under three water regimes and four fertility treatments. Intercropping systems were assessed on the basis of indices such as biomass production and allocation, relative competitive ability, aggressivity, relative yield total and water use efficiency (WUE). Water stress decreased significantly the total biomass production for each species, either in monoculture or in mixtures. N, P, or NP application can significantly improve biomass production of the two species in their mixtures. There was no obvious change trend in root/shoot ratio of B. ischaemum or L. davurica in different mixture proportions. Relative yield total (RYT) values ranged from 0.98 to 1.39. Aggressivity values of B. ischaemum to L. davurica were positive in all water regimes and fertilizations, implying that B. ischaemum was the dominant species. Relative competition intensity values of B. ischaemum (i.e., RCI_B) were less than zero, while greater than zero for L. davurica (i.e., RCI_L), indicating that the effects of intraspecific competition with L. davurica were stronger for B. ischaemum, and the opposite for L. davurica. WUE increased gradually as the proportion of B. ischaemum increased in mixtures, and a 10:2 B. ischaemum:L. davurica mixture proportion had significantly higher WUE. Results suggest that it is advantageous to grow the two species together to maximize biomass production and the recommended mixture ratio was 10:2 of B. ischaemum to L. davurica because it gave higher RYT and significantly higher WUE under conditions of water deficit.