Alternative chaperone machinery may compensate for calreticulin/calnexin deficiency in Caenorhabditis elegans

Proper folding and maintenance of the native structure are central to protein function and are assisted by a family of proteins called chaperones. Calreticulin and calnexin are ER resident chaperones well conserved from worm to human. Calreticulin/calnexin knock-out mice exhibit a severe phenotype, whereas in Caenorhabditis elegans, calreticulin [crt-1(jh101)]- and calnexin [cnx-1(nr2009)]-null mutant worms exhibit only a mild phenotype, suggesting the possible existence of alternative chaperone machinery that can compensate for the deficiency of calreticulin and/or calnexin. In order to rapidly identify the compensatory chaperone components involved in this process, we analyzed the proteome of crt-1(jh101) mutants and [crt-1(jh101);cnx-1(nr2009)] double mutants. When grown at 20 degrees C, we found that five proteins were up-regulated and two proteins were down-regulated in crt-1(jh101) mutants; nine proteins were up-regulated and five proteins were down-regulated in [crt-1(jh101);cnx-1(nr2009)] double mutants. In addition, elevation of the cultivation temperature to 25 degrees C, which is still permissive to growth but causes specific defects in mutants, led to the identification of several additional proteins. Interestingly, the consistent increment of heat shock protein-70 family members (hsp70) together with protein disulfide isomerase (PDI) at all the examined conditions suggests the possible compensatory function imparted by hsp70 and PDI family members in the absence of calreticulin and/or calnexin.     

Cytokine GM-CSF genetic adjuvant facilitates prophylactic DNA vaccine against pseudorabies virus through enhanced immune responses

Granulocyte/macrophage colony-stimulatory factor (GM-CSF) is an attractive adjuvant for a DNA vaccine on account of its ability to recruit antigen-presenting cells (APCs) to the site of antigen synthesis as well as its ability to stimulate the maturation of dendritic cells (DCs). This study evaluated the utility of GM-CSF cDNA as a DNA vaccine adjuvant for glycoprotein B (gB) of pseudorabies virus (PrV) in a murine model. The co-injection of GM-CSF DNA enhanced the levels of serum PrV-specific IgG with a 1.5-to 2-fold increase. Moreover, GM-CSF co-injection inhibited the production of IgG2a isotype. However, it enhanced production of an IgG1 isotype resulting in humoral responses biased to the Th2-type against PrV antigen. In contrast, the co-administration of GM-CSF DNA enhanced the T cell-mediated immunity biased to the Th1-type, as judged by the significantly higher level of cytokine IL-2 and IFN-gamma production but not IL-4. When challenged with a lethal dose of PrV, the GM-CSF co-injection enhanced the resistance against a PrV infection. This suggests that co-inoculation with a vector expressing GM-CSF enhanced the protective immunity against a PrV infection. This immunity was caused by the induction of increased humoral and cellular immunity in response to PrV antigen.     

A Prospective Study of Fatty Liver Index and Incident Hypertension: The KoGES-ARIRANG Study

Background

Although non-alcoholic fatty liver disease is the hepatic manifestation of metabolic syndrome, its influence on hypertension development is poorly understood. We investigated whether fatty liver disease, as assessed by the fatty liver index, could predict the development of hypertension independently of systemic insulin resistance, inflammatory status and adipokine levels.

Methods

Prospective cohort study of 1,521 adults (484 men and 1037 women) aged 40 to 70 years without baseline hypertension examined. An equation was used to calculate fatty liver index and classify patients as follows: fatty liver index <30, no non-alcoholic fatty liver disease; fatty liver index ≥60, non-alcoholic fatty liver disease; and 30≤ fatty liver index <60, intermediate fatty liver index.

Results

During an average of 2.6 years of follow-up, 153 subjects (10.06%) developed hypertension. Fatty liver index was positively associated with baseline blood pressure, homeostasis model assessment of insulin resistance, urinary albumin/creatinine excretion, and high sensitivity C-reactive protein. After adjustment for confounding factors, including markers of insulin resistance, systemic inflammation and adiponectin levels, the odds ratio [95% confidence interval] for the incident hypertension increased in a graded manner with fatty liver index (<30 vs. 30–59 vs. ≥60 = 1 vs. 1.83 [1.16~2.88] vs. 2.09 [1.08~4.055], respectively).

Conclusions

Non-alcoholic fatty liver disease assessed by fatty liver index was an independent risk factor for hypertension. Our findings suggest that fatty liver index, a simple surrogate indicator of fatty liver disease, might be useful for identifying subjects at high risk for incident hypertension in clinical practice.     

Evolution of Cooperation Patterns in Psoriasis Research: Co-Authorship Network Analysis of Papers in Medline (1942–2013)

Background

Although researchers have worked in collaboration since the origins of modern science and the publication of the first scientific journals in the eighteenth century, this phenomenon has acquired exceptional importance in the last several decades. Since the mid-twentieth century, new knowledge has been generated from within an ever-growing network of investigators, working cooperatively in research groups across countries and institutions. Cooperation is a crucial determinant of academic success.

Objective

The aim of the present paper is to analyze the evolution of scientific collaboration at the micro level, with regard to the scientific production generated on psoriasis research.

Methods

A bibliographic search in the Medline database containing the MeSH terms “psoriasis” or “psoriatic arthritis” was carried out. The search results were limited to articles, reviews and letters. After identifying the co-authorships of documents on psoriasis indexed in the Medline database (1942–2013), various bibliometric indicators were obtained, including the average number of authors per document and degree of multi-authorship over time. In addition, we performed a network analysis to study the evolution of certain features of the co-authorship network as a whole: average degree, size of the largest component, clustering coefficient, density and average distance. We also analyzed the evolution of the giant component to characterize the changing research patterns in the field, and we calculated social network indicators for the nodes, namely betweenness and closeness.

Results

The main active research clusters in the area were identified, along with their authors of reference. Our analysis of 28,670 documents sheds light on different aspects related to the evolution of scientific collaboration in the field, including the progressive increase in the mean number of co-authors (which stood at 5.17 in the 2004–2013 decade), and the rise in multi-authored papers signed by many different authors (in the same decade, 25.77% of the documents had between 6 and 9 co-authors, and 10.28% had 10 or more). With regard to the network indicators, the average degree gradually increased up to 10.97 in the study period. The percentage of authors pertaining to the largest component also rose to 73.02% of the authors. The clustering coefficient, on the other hand, remained stable throughout the entire 70-year period, with values hovering around 0.9. Finally, the average distance peaked in the decades 1974–1983 (8.29) and 1984–2003 (8.12) then fell over the next two decades, down to 5.25 in 2004–2013. The construction of the co-authorship network (threshold of collaboration ≥ 10 co-authored works) revealed a giant component of 161 researchers, containing 6 highly cohesive sub-components.

Conclusions

Our study reveals the existence of a growing research community in which collaboration is increasingly important. We can highlight an essential feature associated with scientific collaboration: multi-authored papers, with growing numbers of collaborators contributing to them, are becoming more and more common, therefore the formation of research groups of increasing depth (specialization) and breadth (multidisciplinarity) is now a cornerstone of research success.     

Seasonal and Spatial Variations of Bulk Nitrogen Deposition and the Impacts on the Carbon Cycle in the Arid/Semiarid Grassland of Inner Mongolia,China

Atmospheric nitrogen (N) deposition is an important component that affects the structure and function of different terrestrial ecosystem worldwide. However, much uncertainty still remains concerning the magnitude of N deposition on grassland ecosystem in China. To study the spatial and temporal patterns of bulk N deposition, the levels of N (NH₄ ⁺-N and NO₃ ^--N) concentration in rainfall were measured at 12 sites across a 1200 km grassland transect in Inner Mongolia, China, and the respective N deposition rates were estimated. The inorganic N deposition rates ranged from 4.53 kg N ha^-1 to 12.21 kg N ha^-1 with a mean value of 8.07 kg N ha^-1 during the entire growing season, decreasing steadily from the eastern to the western regions. Inorganic N deposition occurred mainly in July and August across meadow steppe, typical steppe, and desert steppe, which corresponded to the seasonal distribution of mean annual precipitation. A positive relationship was found between inorganic N deposition and mean annual precipitation (R² = 0.54 ~ 0.72, P < 0.0001) across the grassland transect. Annual estimation of inorganic N deposition was 0.67 Pg yr^-1 in Inner Mongolia, China based on the correlation between N deposition rates and precipitation. N deposition was an important factor controlling aboveground biomass and ecosystem respiration, but has no effect on root biomass and soil respiration. We must clarify that we used the bulk deposition samplers during the entire sampling process and estimated the dissolved NH₄ ⁺-N and NO₃ ^--N deposition rates during the entire growing season. Long-term N deposition monitoring networks should be constructed to study the patterns of N deposition and its potential effect on grassland ecosystem, considering various N species, i.e., gaseous N, particle N, and wet N deposition.     

KNOCKDOWN OF THE IONOTROPIC γ‐AMINOBUTYRIC ACID RECEPTOR (GABAR) RDL GENE DECREASES FIPRONIL SUSCEPTIBILITY OF THE SMALL BROWN PLANTHOPPER,Laodelphax striatellus (HEMIPTERA: DELPHACIDAE)

Insect γ‐aminobutyric acid receptors (GABARs) are important molecular targets of cyclodiene and phenylpyrazole insecticides. Previously GABARs encoding rdl (resistant to dieldrin) genes responsible for dieldrin and fipronil resistance were identified in various economically important insect pests. In this study, we cloned the open reading frame cDNA sequence of rdl gene from fipronil‐susceptible and fipronil‐resistant strains of Laodelphax striatellus (Lsrdl). Sequence analysis confirmed the presence of a previously identified resistance‐conferring mutation. Different alternative splicing variants of Lsrdl were noted. Injection of dsLsrdl reduced the mRNA abundance of Lsrdl by 27–82%, and greatly decreased fipronil‐induced mortality of individuals from both susceptible and resistant strains. These data indicate that Lsrdl encodes a functional RDL subunit that mediates susceptibility to fipronil. Additionally, temporal and spatial expression analysis showed that Lsrdl was expressed at higher levels in eggs, fifth‐instar nymphs, and female adults than in third‐instar and fourth‐instar nymphs. Lsrdl was predominantly expressed in the heads of 2‐day‐old female adults. All these results provide useful background knowledge for better understanding of fipronil resistance related ionotropic GABA receptor rdl gene expressed variants and potential functional differences in insects.     

<Emphasis Type="Italic">Lactobacillus curvatus</Emphasis> WiKim38 isolated from kimchi induces IL-10 production in dendritic cells and alleviates DSS-induced colitis in mice

Probiotics such as lactobacilli and bifidobacteria have healthpromoting effects by immune modulation. In the present study, we examined the immunomodulatory properties of Lactobacillus curvatus WiKim38, which was newly isolated from baechu (Chinese cabbage) kimchi. The ability of L. curvatus WiKim38 to induce cytokine production in bone marrow-derived dendritic cells (BMDCs) was determined by enzyme-linked immunosorbent assay. To evaluate the molecular mechanisms underlying L. curvatus Wikim38-mediated IL-10 production, Western blot analyses and inhibitor assays were performed. Moreover, the in vivo anti-inflammatory effects of L. curvatus WiKim38 were examined in a dextran sodium sulfate (DSS)-induced colitis mouse model. L. curvatus WiKim38 induced significantly higher levels of IL-10 in BMDCs compared with that induced by LPS. NF-κB and ERK were activated by L. curvatus WiKim38, and an inhibitor assay revealed that these pathways were required for L. curvatus WiKim38-induced production of IL-10 in BMDCs. An in vivo experiment showed that oral administration of L. curvatus WiKim38 increased the survival rate of mice with DSS-induced colitis and improved clinical signs and histopathological severity in colon tissues. Taken together, these results indicate that L. curvatus Wikim38 may have health-promoting effects via immune modulation, and may thus be applicable for therapy of various inflammatory diseases.     

Probing the critical residues for intramolecular fructosyl transfer reaction of a levan fructotransferase

Levan fructotransferase (LFTase) preferentially catalyzes the transfructosylation reaction in addition to levan hydrolysis, whereas other levan-degrading enzymes hydrolyze levan into a levan-oligosaccharide and fructose. Based on sequence comparisons and enzymatic properties, the fructosyl transfer activity of LFTase is proposed to have evolved from levanase. In order to probe the residues that are critical to the intramolecular fructosyl transfer reaction of the Microbacterium sp. AL-210 LFTase, an error-prone PCR mutagenesis process was carried out, and the mutants that led to a shift in activity from transfructosylation towards hydrolysis of levan were screened by the DNS method. After two rounds of mutagenesis, TLC and HPLC analyses of the reaction products by the selected mutants revealed two major products; one is a di-D-fructose- 2,6':6,2'-dianhydride (DFAIV) and the other is a levanbiose. The newly detected levanbiose corresponds to the reaction product from LFTase lacking transferring activity. Two mutants (2-F8 and 2-G9) showed a high yield of levanbiose (38-40%) compared with the wild-type enzyme, and thus behaved as levanases. Sequence analysis of the individual mutants responsible for the enhanced hydrolytic activity indicated that Asn-85 was highly involved in the transfructosylation activity of LFTase.