5′‐N‐ethylcarboxamide induces IL‐6 expression via MAPKs and NF‐κB activation through Akt,Ca2+/PKC,cAMP signaling pathways in mouse embryonic stem cells

Many studies suggest that adenosine modulates cell responses in a wide array of tissues through potent and selective regulation of cytokine production. This study examined the effects of adenosine on interleukin (IL)‐6 expression and its related signal pathways in mouse embryonic stem (ES) cells. In this study, the adenosine analogue 5′‐N‐ethylcarboxamide (NECA) increased IL‐6 protein expression level. Mouse ES cells expressed the A₁, A_2A, A_2B, and A₃ adenosine receptors (ARs), whose expression levels were increased by NECA and NECA‐induced increase of IL‐6 mRNA expression or secretion level was inhibited by the non‐specific AR inhibitor, caffeine. NECA increased Akt and protein kinase C (PKC) phosphorylation, intracellular Ca²⁺ and cyclic adenosine monophosphate (cAMP) levels, which were blocked by caffeine. On the other hand, NECA‐induced IL‐6 secretion was partially inhibited by Akt inhibitor, bisindolylmaleimide I (PKC inhibitor), SQ 22536 (adenylate cyclate inhibitor) and completely blocked by the 3 inhibitor combination treatment. In addition, NECA increased mitogen activated protein kinase' (MAPK) phosphorylation, which were partially inhibited by the Akt inhibitor, bisindolylmaleimide I, and SQ 22536 and completely blocked by the 3 inhibitor combination treatment. NECA‐induced increases of IL‐6 protein expression and secretion levels were inhibited by MAPK inhibition. NECA‐induced increase of nuclear factor (NF)‐κB phosphorylation was inhibited by MAPK inhibitors. NECA also increased cAMP response element‐binding protein (CREB) phosphorylation, which was blocked by MAPK or NF‐κB inhibitors. Indeed, NECA‐induced increase of IL‐6 protein expression and secretion was blocked by NF‐κB inhibitors. In conclusion, NECA stimulated IL‐6 expression via MAPK and NF‐κB activation through Akt, Ca²⁺/PKC, and cAMP signaling pathways in mouse ES cells. J. Cell. Physiol. 219: 752–759, 2009. © 2009 Wiley‐Liss, Inc.     

Assessment of the Microbial Ecology of Ruminal Methanogens in Cattle with Different Feed Efficiencies

Cattle with high feed efficiencies (designated “efficient”) produce less methane gas than those with low feed efficiencies (designated “inefficient”); however, the role of the methane producers in such difference is unknown. This study investigated whether the structures and populations of methanogens in the rumen were associated with differences in cattle feed efficiencies by using culture-independent methods. Two 16S rRNA libraries were constructed using ∼800-bp amplicons generated from pooled total DNA isolated from efficient (n = 29) and inefficient (n = 29) animals. Sequence analysis of up to 490 randomly selected clones from each library showed that the methanogenic composition was variable: less species variation (22 operational taxonomic units [OTUs]) was detected in the rumens of efficient animals, compared to 27 OTUs in inefficient animals. The methanogenic communities in inefficient animals were more diverse than those in efficient ones, as revealed by the diversity indices of 0.84 and 0.42, respectively. Differences at the strain and genotype levels were also observed and found to be associated with feed efficiency in the host. No difference was detected in the total population of methanogens, but the prevalences of Methanosphaera stadtmanae and Methanobrevibacter sp. strain AbM4 were 1.92 (P < 0.05) and 2.26 (P < 0.05) times higher in inefficient animals, while Methanobrevibacter sp. strain AbM4 was reported for the first time to occur in the bovine rumen. Our data indicate that the methanogenic ecology at the species, strain, and/or genotype level in the rumen may play important roles in contributing to the difference in methane gas production between cattle with different feed efficiencies.Microbial fermentation and ruminal nutrient absorption are key steps in the energy metabolism of cattle. The microbiota in the rumen is highly associated with the diet, age, antibiotic use, and health of host animals (32). Different types of symbiotic anaerobic microorganisms, including bacteria, archaea, ciliated protozoa, and fungi, inhabit the rumen (15), interact with each other, and play important roles in affecting the host''s performance. The microbial-host relationships are highly complex and varied, ranging from mutually beneficial cooperation to competition (10). Among ruminal microbes, bacteria decompose the feed into short-chain (C₁ to C₅) fatty acids, amino acids, H₂, and CO₂, etc. (20). To maintain the low hydrogen level in this habitat, hydrogen-utilizing microbes, such as methanogens, utilize H₂ and carbon substrates, mainly CO₂, acetate, or methanol, to generate methane gas and hence to reduce hydrogen pressure in the rumen (8). However, this process causes a significant (6%) loss of dietary energy in the form of methane emission (14), which contributes to 13 to 19% of global greenhouse gas (16), and is one of the significant agricultural “causative sectors” contributing to global warming (13). Therefore, the energy loss and the consequent methane emission arouse both nutritional and environmental concerns in the livestock industry.Archaeal methanogens are obligate anaerobes (38), and species of the order Methanobacteriales are the most common methanogens found in the rumen (11). Recent studies using culture-independent methods investigating the methanogenic communities in the rumens of sheep and cattle have identified 21 different strains belonging to 13 species in sheep (40, 41, 43, 44) and 13 different strains related to 8 species in cattle (23, 37, 42). In addition, the identification of novel uncultured methanogens in the rumen (23, 33, 40) suggests that the understanding of the methanogenic ecology is limited. Cattle with higher feed efficiencies are reported to produce 20 to 30% less methane (9, 24). However, the linkage between rumen methanogenic composition and the host''s feed efficiency and methane production has not been studied and reported.As one of the indicators of feed efficiency in cattle, residual feed intake (RFI) measures the difference between an animal''s actual feed intake and the expected feed requirements for growth (1, 2). Cattle with low RFI (L-RFI) are designated “efficient,” while animals with high RFI (H-RFI) are designated “inefficient.” A recent study reporting a correlation between bacterial profiles and cattle RFI has suggested the probable linkage between rumen microbial ecology and feed efficiency in cattle (7). Therefore, we hypothesized that the structures and populations of methanogens may be also associated with RFI and methane gas production by the host. In this study, the compositions of methanogens in the rumens of cattle with different RFIs were compared by sequence analysis of the partial 16S rRNA genes (∼800 bp) generated from two constructed libraries, using pooled DNA from efficient (L-RFI) and inefficient (H-RFI) animals. The population of selected species in each steer was evaluated using quantitative real-time PCR (qRT-PCR) analysis, and the correlation between methanogenic structure/population and cattle RFI was investigated.     

Optimization and oxidative stability of the microencapsulated conjugated linoleic acid

We used response surface methodology to optimize the preparation conditions of conjugated linoleic acid (CLA) microcapsules for maximum entrapment efficiency. Three independent variables were used: the ratio of CLA core material to agar and waxy corn starch wall material (X₁), the temperature of dispersion fluid (X₂), and the concentration of emulsifier (X₃). The optimized values of X₁, X₂, and X₃ were found to be 3.82:6.18, 19.97 °C, and 0.34%, respectively. The CLA oxidation stability was significantly protected by microencapsulation. These results suggest that CLA-loaded microcapsules can be used as a means to enhance not only the entrapment efficiency but also the oxidative stability of CLA.     

Structural characteristics of low-glycemic response rice starch produced by citric acid treatment

The structural characteristics of citric acid-treated rice starch, which was subjected to autoclaving and stored at a high temperature under acidic conditions, were investigated by high performance anion-exchange chromatography, multi-angle laser-light scattering, X-ray diffraction, differential scanning calorimetry (DSC), nuclear magnetic resonance, and scanning electron microscopy. The citric acid-treated rice starch contained chains of different lengths (DP 7−70) and had an A + V type polymorphism. The DSC thermogram of acid-treated rice starch showed a broad endothermic peak, which indicated that the structure of the acid-treated rice starch contained a number of double helices with various melting temperatures. Microscopic observation showed that the internal structure of the acid-treated starch displayed more or less spherical lumps that could be composed of short chains and amylose–lipid complex. The digestive properties of acid-treated rice starch were altered by heat processing such as cooking and autoclaving because crystalline regions were converted to amorphous regions or lamellae.     

Molecular cloning and expression pattern of 14-3-3ζ from the malaria vector, Anopheles sinensis

14-3-3 proteins are known to play a pivotal role in cell survival, apoptosis and signal transduction. The 14-3-3ζ isoform has been cloned and characterized from many eukaryotic organisms, including the fruit fly and silkworm. However, no study on mosquito 14-3-3 has been reported to date. In an attempt to investigate the function of 14-3-3 in midgut epithelial cells undergoing apoptosis, a cDNA library was generated from the malaria vector, Anopheles sinensis , which was treated with apoptosis-inducing Actinomycin-D. We were able to identify and obtain A. sinensis 14-3-3ζ cDNA ( Ansi14-3-3ζ ) from expressed sequence tags (EST) analysis after conducting massive sequencing of the A. sinensis cDNA library. Ansi14-3-3ζ has very high homology to 14-3-3 homologs of various insects, such as Anopheles gambiae (100%), Aedes aegypti (100%), Drosophila melanogaster (96%), Bombyx mori (93%), Apis mellifera (93%) and Mus musculus (81%), indicating that mosquito 14-3-3ζ is a highly conserved gene in diverse organisms. Analysis of temporal expression patterns showed that Ansi14-3-3ζ mRNA is highly expressed in egg, early pupae and adult stages and is also expressed, although at low levels, in fourth instar larvae and late pupae. In response to two immune elicitors (lipopolysaccharide and laminarin), no striking induction of 14-3-3ζ mRNA was observed in A. sinensis . Further studies of the precise biological function, inducibility and subcellular distribution of 14-3-3ζ are required in Plasmodium invasion-induced apoptotic midgut cells in A. sinensis in the context of the Time Bomb model.     

The Janzen-Connell effect on the population dynamics of a Fagus engleriana- Cyclobalanopsis oxyodon community in a subtropical zone of China

The Janzen-Connell (J-C) hypothesis provides a mechanism explaining the high species diversity in tropical rainforests. It postulates that predation could cause greater mortality on seeds and seedlings near their parental trees. In this study, we tested the hypothesis in a subtropical zone, a mixed evergreen-deciduous broad-leaved forest dominated by the Fagus engleriana and Cyclobalanopsis oxyodon. The study area was in the Shennongjia region, a key area of biodiversity conserva-tion in both China and the world. The recruitment probability index was used to detect the J-C effect on nine species of the community, which were more than 50 individuals. Six large adults of each species were selected, and the numbers of saplings and adults were counted at the distance intervals of 0-5, 5-10, 10-15, 15-20, and 20-25 m from each focal tree. Two species in saplings stage and six in adult stage supported the J-C hypothesis, but their χ2 was not significant. Three species, the F. engleri-ana, Rhododendron hypoglaucum, and Toona sinensis, showed a strong Hubbell pattern in the adult stage. Because of these results, we reject the J-C hypothesis and conclude that species could recruit near the conspecific trees in subtropical forest. The reasons why the J-C hypothesis fails to explain the species diversity in this community are the shortage of seed-consuming agents of subtropical forest and the influence of microsite topo-graphic variation.     

Regeneration pattern analysis of Quercus liaotungensis in a temperate forest using two-dimensional wavelet analysis

This paper introduces the two-dimensional (2D) wavelet analysis as a general interrogative technique for the detection of spatial structure in lattice data. The 2D wavelet analysis detects components of hierarchical structure and displays the locational information of the components. Patches and gaps of different spatial scales in graphical presentation of wavelet coefficients can be linked to the local ecological processes that determine patterns at stand or landscape scales. Derived from the 2D wavelet transform function, the calculation of wavelet variance can reduce the four-dimensional data of wavelet coefficients to a two-dimensional wavelet variance function and quantify the contribution of the given scale to the overall pattern. We illustrate the use of the 2D wavelet analysis by analyzing two simulated patterns and identifying the regeneration pattern of the Quercus liaotungensis in a warm temperate forest in north China. Our results indicate that the recruitment of Q. liaotungensis occurs in an overlapping area between the patch of adult and canopy gap at scales of 45 m×45 m–70 m×70 m and 20 m×20 m–30 m×30 m. The regeneration pattern of Q. liaotungensis can be mainly ascribed to a trade-off between two ecological processes: recruitment around parent trees and the physiological light requirements of seedlings and saplings. Our results provide a general portrayal of the regeneration pattern for the dispersal-limited and shade-intolerant Quercus species. We find that the two-dimensional wavelet analysis efficiently characterizes the scale-specific pattern of Q. liaotungensis at different life-history stages.     

Cloning and blood‐meal dependent induction pattern of apolipophorin‐III from Anopheles sinensis

Apolipophorin‐III is known to play a role in transporting lipids in insects, and much attention has been paid to lepidopteran insects' apolipophorin. Thus, we were interested in examining the effects of blood‐meal on the expression pattern of apolipophorin‐III in mosquitoes. This led us to clone and partially characterize the full‐length cDNA of apoLp‐III (AnsiApoLp‐III) from Anopheles sinensis. Analysis of AnsiApoLp‐III cDNA shows that the 728‐bp sequence has a 582‐bp protein‐coding region with 94 bp of putative 5′ untranslated region and 152 bp of 3′ untranslated region. The deduced amino acid sequence begins with a methionine codon at position 95 and extends to position 674, encompassing a polypeptide of 193 amino acids. AnsiApoLp‐III has the highest identity (63%) to Culex quinquefasciatus apoLp‐III. Temporal expression pattern analysis shows that although AnsiApoLp‐III was expressed at all developmental stages, it was highly detected at egg and adult stages in the female mosquitoes. In addition, we found out that AnsiApoLp‐III was induced in An. sinensis adult females after uptaking a blood‐meal. Spatial expression patterns of AnsiApoLp‐III shows that AnsiApoLp‐III mRNA was strongly induced at day 1 and gradually decreased from day 1 to day 4 in the ovaries. Most interestingly, AnsiApoLp‐III mRNA in the Malpighian tubule was strongly induced at day 1, decreased during days 1–3, and then became elevated again at day 4. These data suggest that blood‐meal influences AnsiApoLp‐III mRNA induction in ovaries and Malpighian tubules. It remains to further elucidate the biological roles of AnsiApoLp‐III in these organs.