Protective effects and time course of Huangqi on early-stage free radical injury following brain trauma in rats

BACKGROUND： Huangqi （Astragalus mongholicus）, a Chinese herb, has already been included in the ＂Chinese Pharmacopoeia＂ for the treatment of ischemic cerebrovascular disease. Secondary injury following brain injury is associated with free radical production, and Huangqi possesses the ability to ameliorate free radical-mediated injury. OBJECTIVE： This study was designed to observe the correlation between anti-free-radical properties of Huangqi and early histological changes of brain tissues following traumatic brain injury. DESIGN, TIME AND SETTING： This study, a randomized, controlled, animal experiment, was performed from May 2006 to June 2007 at the Experimental Center of Science and Technology, School of Basic Science, Liaoning Medical University, Jinzhou City, Liaoning Province, China. MATERIALS： Healthy, adult, Sprague Dawley rats of either gender were included. Huangqi injection was purchased from Heilongjiang Provincial Zhenbaodao Pharmaceutical Co., Ltd., China （National License Medical Number： Z23020781）. Na^＋-K^＋-adenosine triphosphatase （ATPase）, Ca^2＋-ATPase, and Mg^2＋-ATPase, as well as kits to measure superoxide dismutase （SOD） activity and malondialdehyde （MDA） content, were purchased from Nanjing Jiancheng Biological Reagent Company, China. METHODS： Seventy-two rats were randomly divided into three groups, with 24 rats in each group： （1） sham-operated group： rats were only exposed, but not injured; （2） model group： brain focal laceration rat models were established by free-falling. These groups were intraperitoneally injected with saline, once every 10 hours; （3） Huangqi group： rats were intraperitoneally injected with 4 mL/kg Huangqi （2 g/mL）, once every 10 hours, following brain focal laceration by free-falling. MAIN OUTCOME MEASURES： Ultrastructural changes in brain tissue were observed under an electron microscope 24 hours after injury. The water content of brain tissue was measured using the dry-wet weight method. In addition, the activity of ATPase and SOD, as well as MDA content, was analyzed using biochemical indicators at 4, 24, and 48 hours after injury. RESULTS： All 72 rats were included in the final analysis. At 4, 24, and 48 hours after injury, ATPase activity was significantly reduced in the model and Huangqi groups than in the sham-operated group （P 〈 0.05）, and this was reduction was time-dependent. At four hours after injury, no significant difference in ATPase activity was detected between the Huangqi group and the model group （P 〉 0.05）. At 24 and 48 hours after injury, ATPase activity in the Huangqi group gradually decreased, but remained significantly greater than that in the model group （P 〈 0.05）. At four hours after injury, when compared with the sham-operated group, the MDA content in the model group significantly increased and remained at a high level, while SOD activity significantly decreased （P 〈 0.05）. In the Huangqi group, MDA content and SOD activity did not change at four hours after injury. However, MDA content significantly decreased, and SOD activity significantly increased, at 24 and 48 hours after injury, compared with the model group （P 〈 0.05）. Moreover, at 24 and 48 hours after injury, the water content of brain tissue was significantly lower in the Huangqi group than in the model group （P 〈 0.05）. Ultrastructural examination of cerebral cortical neurons revealed severe damage in the model group, compared to the sham-operated group, while only mild injury was observed in the Huangqi group. CONCLUSION： The protective effects of Huangqi against traumatic brain injury correlates with decreasing MDA content and increasing SOD activity.

Antifungal Activity of Chitosan on Fusarium sulphureum in Relation to Dry Rot of Potato Tuber

The antifungal activity of chitosan on Fusarium sulphureum in relation to the inhibitory effect on dry rot of potato tuber was investigated. The results showed spore germination and mycelial growth of F. sulphureum were inhibited by chitosan treatment and the inhibitory effect was highly correlated with chitosan concentration used in this study. Morphological changes such as intertwisting hyphal, distortion, and swelling with excessive branching were observed by scanning electron microscopy （SEM） observation. Transmission electron microscopy （TEM） observation further indicated the ultrastructural alterations of hyphae. These changes included abnormal distribution of cytoplasma, non-membraneous inclusion bodies assembling in cytoplasm, considerable thickening of the hyphal cellular walls, and very frequent septation with malformed septa. Application of chitosan at higher concentration caused serious damage to fungal hyphae, including cellular membrane disorganisation, cell wall disruption, and breaking of inner cytoplast. New hyphae （daughter hyphae） inside the collapsed hyphal cells was often detected in the cytoplasm of chitosan-treated hyphae. In vivo tests showed that chitosan treatment at 0.5 or 1% effectively controlled the dry rot of potato tuber inoculated with a spore suspension ofF. sulphureum. However, the chitosan treatment at 1% caused phytotoxicity to potato tuber. This study suggests that the use of chitosan could be a promising handling as a natural fungicide to partially substitute for the synthetic fungicides in potato tuber.

Venom gland of the ichneumonid Diadromus collaris： morphology, ultrastructure and age-related changes

Females of the solitary parasitoid Diadromus collaris （Insecta： Hymenoptera： Ichneumonidae） lay eggs in the pupae of Plutella xylostella （Lepidoptera： Plutellidae）, and the venom is synchronously injected into hosts. The venom apparatus consists of two glandular tubules terminating in a common reservoir, A ductule connects the reservoir with the sting apparatus, by which the reservoir content enters the latter. Secretory units line the two glandular tubules. All secretory cells belong to dermal gland type Ⅲ. Dermal gland cells in glandular tubules are more abundant and developed than those in the reservoir. There are extensive rough endoplasmic reticulum and electrondense vesicles, and the microvilli are well developed. By the cuticle-lined central funnel secretion products of secretory units reach the reservoir. Moreover, the secretory apparatus undergoes age-related changes. The secretory units in the venom gland are better developed and more vigorous 7 days after eclosion than those 1 day after eclosion; autolytic processes occur 15 days after eclosion, and the tissue of the reservoir is more prostrate 15 day after eclosion than those 1 day after eclosion. The ovipostion peak of this parasitoid, about 3-7 days after eclosion, corresponds with the period when the venom gland is highly developed in the life span of the wasp.

Effects of chlorine dioxide on morphology and ultrastructure of Fusarium sulphureum and its virulence to potato tubers

The inhibitory effect and its virulence of chlorine dioxide(ClO_(2))against dry rot of potato were investigated.Potatoes were treated by ClO_(2),then observed for indoor bioassay,scanning electron microscopy(SEM)and transmission electron microscopy(TEM)were used to observe the morphology and ultrastructure of hyphae,and evaluated the control efficiency of ClO_(2) on potato tuber(LK99)dry rot by F.sulphureum pre-treatment.The results showed that the pathogen of potato dry rot was sensitive to ClO_(2),the virulence of regression of y=5.05+7.308x,EC50 and EC90 were 0.3490 and 0.6261 respectively,the treatment of ClO_(2) could significantly inhibit the spore germination and mycelium growth of F.sulphureum,which was in a concentration-dependent manner,SEM and TEM observed that the morphology and ultrastructure of F.sulphureum hyphae were regularly damaged by ClO_(2),in vivo experiment further indicated that ClO_(2) could effectively control the dry rot of potato tubers with F.sulphureum,and ClO_(2) at the concentration of 0.75 ug/mL could significantly reduce the incidence of potato tuber dry rot and lesion expansion rate.The study showed that ClO_(2) could greatly against the pathogen of F.sulphureum,which could provide a scientific theoretical basis for the safe and efficient application of ClO_(2) in the prevention and control of potato diseases after harvest.