Comparative analysis of intrinsic skin aging between Caucasian and Asian subjects by slide‐free in vivo harmonic generation microscopy

Phenotypical and functional differences in the intrinsic skin aging process of individuals between Caucasians and Asians have generated considerable interest in dermatology and cosmetic industry. Most of the studies focused on the stratum corneum, and in some other studies inter‐individual differences overwhelms the racial difference. None of the studies comparatively analyzes the difference from the histopathological point of view. Here we report our harmonic generation microscopy study to analyze the difference of intrinsic aging between Caucasian and Asian skin from a histopathological point of view. As a result, the cellular and nuclear areas of basal cells in Caucasian subjects were found to increase at the same rate as the Asian subjects, ideal for scoring age. The maximum thickness of the viable epidermis, the dermal papilla (DP) volume per unit area and the depth of the DP zone in Caucasians were found to decrease at faster rates than those in Asians.     

A Parameterized Model of Amylopectin Synthesis Provides Key Insights into the Synthesis of Granular Starch

A core set of genes involved in starch synthesis has been defined by genetic studies, but the complexity of starch biosynthesis has frustrated attempts to elucidate the precise functional roles of the enzymes encoded. The chain-length distribution (CLD) of amylopectin in cereal endosperm is modeled here on the basis that the CLD is produced by concerted actions of three enzyme types: starch synthases, branching and debranching enzymes, including their respective isoforms. The model, together with fitting to experiment, provides four key insights. (1) To generate crystalline starch, defined restrictions on particular ratios of enzymatic activities apply. (2) An independent confirmation of the conclusion, previously reached solely from genetic studies, of the absolute requirement for debranching enzyme in crystalline amylopectin synthesis. (3) The model provides a mechanistic basis for understanding how successive arrays of crystalline lamellae are formed, based on the identification of two independent types of long amylopectin chains, one type remaining in the amorphous lamella, while the other propagates into, and is integral to the formation of, an adjacent crystalline lamella. (4) The model provides a means by which a small number of key parameters defining the core enzymatic activities can be derived from the amylopectin CLD, providing the basis for focusing studies on the enzymatic requirements for generating starches of a particular structure. The modeling approach provides both a new tool to accelerate efforts to understand granular starch biosynthesis and a basis for focusing efforts to manipulate starch structure and functionality using a series of testable predictions based on a robust mechanistic framework.     

Primary structure of the Drosophila laminin B2 chain and comparison with human, mouse, and Drosophila laminin B1 and B2 chains

Laminin, a major component of basement membranes, is a large glycoprotein consisting of three disulfide-bonded subunits, A, B1, and B2. We have isolated and sequenced a Drosophila laminin B2 chain cDNA clone that spans 5737 nucleotides. The deduced amino acid sequence predicts that the mature and nonglycosylated polypeptide has a chain length of 1606 residues (Mr = 178,665). This B2 chain contains 100 half-cystine residues, most of which are located in two cysteine-rich domains, and 11 N-X-S or N-X-T sequences which are potential sites of N-linked glycosylation. The predicted secondary structure reveals the presence of six structurally distinct domains, of which two are mainly alpha-helical, two are cysteine-rich with homologous repeats, and two are globular regions. The Drosophila B2 chain is 40.3 and 41.1% identical to the human and mouse B2 chains, respectively, and 29.6, 30.0, and 29.4% identical to the Drosophila, human, and mouse B1 chains, respectively.     

Characterization of pneumolysin from Streptococcus pneumoniae,interacting with carbohydrate moiety and cholesterol as a component of cell membrane

The cytolytic mechanism of cholesterol-dependent cytolysins (CDCs) requires the presence of cholesterol in the target cell membrane. Membrane cholesterol was thought to serve as the common receptor for these toxins, but not all CDCs require cholesterol for binding. One member of this toxin family, pneumolysin (PLY) is a major virulence factor of Streptococcus pneumoniae, and the mechanism via which PLY binds to its putative receptor or cholesterol on the cell membrane is still poorly understood. Here, we demonstrated that PLY interacted with carbohydrate moiety and cholesterol as a component of the cell membrane, using the inhibitory effect of hemolytic activity. The hemolytic activity of PLY was inhibited by cholesterol-MβCD, which is in a 3β configuration at the C3-hydroxy group, but is not in a 3α-configuration. In the interaction between PLY and carbohydrate moiety, the mannose showed a dose-dependent increase in the inhibition of PLY hemolytic activity. The binding ability of mannose with truncated PLYs, as determined by the pull-down assay, showed that mannose might favor binding to domain 4 rather than domains 1–3. These studies provide a new model for the mechanism of cellular recognition by PLY, as well as a foundation for future investigations into whether non-sterol molecules can serve as receptors for other members of the CDC family of toxins.     

Effect of different diets on the growth and development of Harmonia axyridis (Pallas)

Harmonia axyridis (Pallas) is an important natural enemy of crop pests. Feeding H. axyridis through artificial diets (ADs) is an important means to achieve large-scale production. In this study, the effects of different diets on the growth, development and reproduction of H. axyridis were comprehensively evaluated, and the reasons for the reduced reproductive capacity of H. axyridis fed ADs were preliminarily explored. Artificial diets were prepared using pig liver and pork as the main ingredients. Larval duration, larval survival rate, egg production and other traits were comprehensively evaluated. Harmonia axyridis fed ADs during both the larval and adult periods completed growth and development from larva to adult but had a prolonged development duration (6.13-day extension) and reduced survival rate (15.3% reduction) in the larval stage. In addition, adults could not lay eggs. Next, individuals of H. axyridis were fed Megoura japonica (Matsumura) in the larval stage and an AD, adequate aphids (AA) or an artificial diet plus 5 (AD5), 10 (AD10) or 25 (AD25) aphids in the adult stage. The adults in the AD group produced a small number of eggs (103.3 eggs). When aphids were added to the diet, egg production gradually increased with the number of aphids added. The AD25 group exhibited no significant difference in egg production compared with that in the AA group (983.8 eggs and 1,158.3 eggs, respectively). Anatomical observations of the H. axyridis adults in these five groups revealed that ovary development was slowest in the AD group. In addition, we found that the levels of vitellogenin and juvenile hormone were significantly lower in the AD group than in the AA group. These results provide a foundation for formulating ADs for H. axyridis and improving the large-scale reproduction of this species.     

Neutrophil depletion does not prevent lung edema after endotoxin infusion in goats

Neutropenia was produced in goats by injection of either nitrogen mustard, (1.5 mg/kg) or hydroxyurea (200 mg X kg-1 X day-1). A nitrogen mustard (M + E) group (n = 6), a hydroxyurea (H + E) group (n = 5), and a control (E) group (n = 7) were given 1-h infusions of endotoxin (5 micrograms/kg total dose), then monitored for up to 5 h. Postmortem extravascular lung water (EVLW) was significantly higher in the M + E group (14.2 +/- 4.4 ml/kg) and the E group (11.9 +/- 3.9 ml/kg) when compared with a normal control (6.6 +/- 1.3 ml/kg) group that did not receive endotoxin. EVLW in a group made neutropenic with nitrogen mustard (6.7 +/- 1.3 ml/kg) and the H + E (7.9 +/- 1.5 ml/kg) groups were not statistically different from each other or from normal controls. Circulating neutrophil counts averaged 32 +/- 42 cells/microliter in the M + E group and 180 +/- 210 cells/microliter in the H + E group. Only minimal histological changes were seen in the H + E group, but the E and M + E lungs had severe pulmonary edema. We conclude that neutrophils are not required for increased EVLW and decreased arterial O2 partial pressure after endotoxin infusion, and hydroxyurea prevents at least part of the pulmonary edema after endotoxin by a mechanism that is not neutrophil dependent.     

一株支气管炎鲍特杆菌国家标准菌种的再鉴定

通过生化试验、质谱鉴定、16S rRNA基因序列分析、全基因组序列测定及生物信息学分析等方法对国家标准菌种CMCC(B)40001进行再鉴定。对菌株的毒力、耐药和MLST进行分析，并对鲍特杆菌（Bordetella spp.）的群体进化进行分析。结合不同方法，CMCC(B)40001再鉴定为支气管炎鲍特杆菌（Bordetella bronchiseptica），且其作为标准菌种能够发挥国家标准描述的质控作用。同时获取该菌株的新ST型，在进化关系上，其与百日咳鲍特杆菌(Bordetella pertussis)和副百日咳鲍特杆菌(Bordetella parapertussis)遗传距离近。本研究再鉴定了国家标准菌种CMCC(B)40001为支气管炎鲍特杆菌，并分析了其遗传特征，为国家标准菌种的应用提供资源描述支持。