Mice Deficient in Proglucagon-Derived Peptides Exhibit Glucose Intolerance on a High-Fat Diet but Are Resistant to Obesity

Homozygous glucagon-GFP knock-in mice (Gcg ^gfp/gfp) lack proglucagon derived-peptides including glucagon and GLP-1, and are normoglycemic. We have previously shown that Gcg ^gfp/gfp show improved glucose tolerance with enhanced insulin secretion. Here, we studied glucose and energy metabolism in Gcg ^gfp/gfp mice fed a high-fat diet (HFD). Male Gcg ^gfp/gfp and Gcg ^gfp/+ mice were fed either a normal chow diet (NCD) or an HFD for 15–20 weeks. Regardless of the genotype, mice on an HFD showed glucose intolerance, and Gcg ^gfp/gfp mice on HFD exhibited impaired insulin secretion whereas Gcg ^gfp/+ mice on HFD exhibited increased insulin secretion. A compensatory increase in β-cell mass was observed in Gcg ^gfp/+mice on HFD, but not in Gcg ^gfp/gfp mice on the same diet. Weight gain was significantly lower in Gcg ^gfp/gfp mice than in Gcg ^gfp/+mice. Oxygen consumption was enhanced in Gcg ^gfp/gfp mice compared to Gcg ^gfp/+ mice on an HFD. HFD feeding significantly increased uncoupling protein 1 mRNA expression in brown adipose and inguinal white adipose tissues of Gcg ^gfp/gfp mice, but not of Gcg ^gfp/+mice. Treatment with the glucagon-like peptide-1 receptor agonist liraglutide (200 mg/kg) improved glucose tolerance in Gcg ^gfp/gfp mice and insulin content in Gcg ^gfp/gfp and Gcg ^gfp/+ mice was similar after liraglutide treatment. Our findings demonstrate that Gcg ^gfp/gfp mice develop diabetes upon HFD-feeding in the absence of proglucagon-derived peptides, although they are resistant to diet-induced obesity.     

Down-regulation of senescence marker protein 30 by iron-specific chelator deferoxamine drives cell senescence

To our knowledge, this is the first study to report down-regulation of senescence marker protein 30 (SMP30) by iron-specific chelator deferoxamine (DFO) on FAO cell senescence, using a DNA microarray. Furthermore, DFO treatment increased senescence marker β-galactosidase activity, whereas this activity was attenuated by overexpression of SMP30. Our data suggested that down-regulation of SMP30 drives cell senescence in iron-chelated condition.     

Inter-annual variation in the response of leaf-out onset to soil moisture increase in a teak plantation in northern Thailand

To understand the impact of inter-annual climate change on vegetation-atmosphere mass and energy exchanges, it has become necessary to explore changes in leaf-out onset in response to climatic fluctuations. We examined the response of leaf-out and transpiration onset dates to soil moisture in a teak plantation in northern Thailand based on a 12-year leaf area index and sap flow measurements. The date of leaf-out and transpiration onset varied between years by up to 40 days, and depended on the initial date when the relative extractable water in a soil layer of 0–0.6 m (Θ) was greater than 0.2 being consistent with our previous results. Our new finding is that the delay in leaf-out and transpiration onset relative to the initial date when Θ?>?0.2 increases linearly as the initial date on which Θ?>?0.2 becomes earlier. The delay spans about 20 days in years when Θ?>?0.2 occurs in March (the late dry season)—much earlier than usual because of heavy pre-monsoon rainfalls—while there is little delay in years when Θ?>?0.2 occurs in May. This delay indicates the influence of additional factors on leaf-out onset, which controls the delay in the response of leaf-out to soil moisture increase. The results increased our knowledge about the pattern and extent of the changes in leaf phenology that occur in response to the inter-annual climate variation in tropical regions, where, in particular, such research is needed.     

Endogenous thiol protease inhibitor from rat liver

A thiol protease inhibitor was purified from rat liver by a rapid procedure involving heat treatment of the post-lysosomal fraction, affinity chromatography on papain-Sepharose 4B and Sephadex G-75. The purified inhibitor appeared homogeneous on sodium dodecyl sulfate electrophoresis. The inhibitor had a molecular weight of about 11,500 and consisted of three forms (pI 4.9, 5.2 and 5.6). The preparation inhibited thiol proteases, such as papain, cathepsin H, cathepsin B and cathepsin L, but not serine proteases (trypsin, chymotrypsin, mast cell protease and cathepsin A) or cathepsin D.     

Grouping of isolates in AG 2 ofRhizoctonia solani by total cellular fatty acid analysis

Total-cellular fatty acid compositions of 34 isolates ofRhizoctonia solani belonging to intraspecific groups (ISGs) of anastomosis group (AG) 2, i.e., AG 2-1, AG 2-2 IIIB (mat rush), AG 2-2 IV (sugar beet), AG 2-2 LP (turfgrass), and AG 2–3 (soybean), were compared. The major fatty acids identified were palmitic, stearic, and oleic acids. Principal component analysis based on the percentage composition of total cellular fatty acids revealed consistently low variability among isolates of a single ISG of AG 2. Average linkage cluster analysis showed that isolates obtained from turfgrass representing a newly proposed group, AG 2-2 LP, were differentiated from other AG 2 ISGs. Isolates of another newly proposed group AG 2–3, from diseased soybean were also closely related to AG 2-1 and AG 2-2 IIIB but distinguishable from the AG 2-1 and AG 2-2 LP isolates by the average linkage cluster analysis. These results suggested that the percentage composition of total-cellular fatty acids is a distinct characteristic for the five ISGs belonging to AG 2, and fatty acid analysis is useful for the differentiation and characterization of these ISGs of AG 2 inR. solani.