Biochemical Investigations of Sclerotial Exudates of Sclerotium rolfsii and their Antifungal Activity

Exudates from sclerotia of two Sclerotium rolfsii isolates (one causing collar rot in Cicer arietinum, isolate VC971, and the other leaf spots in Rauvolfia serpentina, isolate VL016) were assayed for their antifungal activity against 26 fungi consisting of plant parasites as well as saprophytes. Spore germination of all the test fungi was affected by the exudates reaching 100% in some cases. Foliar spray with exudates of isolate VL016 significantly reduced disease incidence of balsam (Impatiens balsamina) powdery mildew caused by Erysiphe cichoracearum and pea (Pisum sativum) powdery mildew caused by Erysiphe pisi, under field conditions. Characterization of exudates from 25 isolates of S. rolfsii revealed pH ranging from 3.8 to 5.3 and colour from light yellow to deep yellow. Among the phenolic acids found in the exudates were tannic, gallic, caffeic, vanillic, ferulic, chlorogenic and cinnamic acids. Oxalic acid was also found in varied amounts. Among the phenolic acids, ferulic acid was found to be present at high concentration in exudates of most isolates (3.9–153.4 μg/ml). The antioxidant properties of phenolics, which generally inhibit fungal morphogenesis including spore germination along with the antifungal nature of some phenolics are chiefly attributed to the inhibitory effect of sclerotial exudates of S. rolfsii. Additionally, both the isolates VC971 and VL016 showed almost similar antifungal activities despite they are of different origin and thereby demonstrate the antifungal nature of sclerotial exudates.     

Epichloë endophyte affects the root colonization pattern of belowground symbionts in a wild grass

Plants host multiple symbionts that interact with each other affecting plant performance and regulating their establishment. Here, we analyzed how the association with Epichloë endophytes affects belowground colonization by Dark Septate Endophytes (DSE) and arbuscular mycorrhizal fungi (AMF) in the grass Bromus auleticus. Epichloë-symbiotic (E+) and Epichloë-non symbiotic (E−) plants were sampled from a long-term experimental plot and colonization structures were analyzed in the roots. We also examined the influence of Epichloë exudates on the in vitro growth of DSE Microdochium bolleyi isolated from roots. Epichloë symbiosis increased AMF colonization, although differences were not significant. Despite the lack of differences in total DSE colonization, in concordance with in vitro findings, a higher significant abundance of microsclerotia was observed in E+ plants. A negative correlation between total mycorrhizal and DSE was found. Our findings show a more uniform root colonization pattern in E+ plants, suggesting a root symbiosis modulating role.     

高嵌体与纤维桩核冠修复对后牙牙体缺损疗效观察及对患者咀嚼能力和牙龈状况的影响

摘要 目的：观察高嵌体修复与纤维桩核冠修复对后牙牙体缺损疗效及对患者咀嚼能力和牙龈状况的影响。方法：选取2020年11月～2021年11月收治的60例牙体缺损患者作为研究对象,根据患者治疗意愿分为对照组和研究组,其中对照组26例、观察组34例。对照组行纤维桩核冠修复治疗,观察组行高嵌体修复治疗,对比两组患者修复效果、咀嚼功能、牙龈指数（GI）和菌斑指数（PLI）评分、并发症发生情况、满意度。结果：经统计发现,观察组邻面接触、表面质地、边缘密合度、舒适度等均优于对照组,两组比较具有明显差异（P<0.05）;修复前,两组患者咀嚼功能评分比较无差异（P>0.05）,修复后,观察组较对照组高（P<0.05）;修复前,两组GI和PLI评分比较无差异（P>0.05）,修复后,两组评分均有所降低,且观察组低于对照组（P<0.05）;观察组并发症发生率为2.94 %,对照组并发症发生率为11.54 %,观察组与对照组比较无差异（P>0.05）;观察组患者满意度为94.12 %,对照组患者满意度为73.08 %,观察组明显高于对照组（P<0.05）。结论：高嵌体修复与纤维桩核冠修复用于治疗牙体缺损,高嵌体修复的临床疗效更佳,患者咀嚼能力和牙龈健康程度明显提升,GI和PLI评分明显降低,有效减少并发症,提高满意度。值得临床推广使用。     

Bioassay and Identification of Root Exudates of Three Fruit Tree Species

A laboratory bioassay was designed to determine the aileiopathic potential of root exudates of three fruit tree species on apple germination. The results showed that root exudates of apple （Malus pumila L.） and peach （Prunus persica L.）, each at concentrations of 0.02 and 0.2 mg/L, inhibited germination and radicle growth of apple seeds by 56.7%, 60.7%, 51.5%, and 59.3%, respectively. The corresponding shoot growth inhibition rate was 49.5%, 46.7%, 36. 4%, and 44%, respectively. Root exudates of jujube （Ziziphus jujuba Mill.） had no significant effect on apple seeds. Qualitative determination of root exudates of apple, peach, and jujube tree was developed with gas chromatography-mass spectrometry. The root exudates of apple seedlings mainly contain organic acids, glycol, esters, and benzenphenol derivatives. Peach root exudates contained phenolic acids and benzenphenoi derivatives in addition to two unidentified compounds. The root exudates of jujube did not contain any phenolic acids.     

弹性橡胶管芯技术用于困难气道行双腔气管导管插管的可行性研究

目的:研究弹性橡胶管芯技术应用于困难气道行双腔气管导管插管的可行性。方法:选择择期胸科手术并行双腔气管导管插管患者40例,并将其随机分为Mc Coy喉镜组(M组)和弹性橡胶管芯组(B组)。M组患者使用Mc Coy喉镜行双腔气管插管,B组患者以弹性橡胶管芯行双腔气管插管。观察和比较插管前后两组患者生命体征的变化、插管次数、所用时间以及由插管造成的损伤发生率。结果:1插管后即刻以及插管后1 min、5min,患者平均动脉压(MAP)、心率(HR)均呈不同程度升高,B组升高程度明显小于M组(P<0.01)。2B组插管时遇到的阻力明显小于M组(P<0.05),插管尝试次数以及完成插管所用的时间均少于或短于M组(P<0.05)。3术后3小时以及24小时,B组由插管导致的声嘶与咽痛的发生率明显低于M组(P<0.05)。4术后48小时,B组患者气道粘膜损伤的发生率明显低于M组(P<0.05)。结论:弹性橡胶管芯技术应用于困难气道行双腔气管导管插管安全有效。     

Food sources for adult Diachasmimorpha longicaudata, a parasitoid of tephritid fruit flies: effects on longevity and fecundity

We report the results of a study on potential food sources of the widely distributed Indo‐Australian braconid fruit fly parasitoid Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae). Adults sustained life on diets of fruit juice or fruit pulp, a homopteran and its associated honeydew, or extrafloral nectary secretions. Longevities on all these foods and fecundity on fruit juice were comparable to those achieved on the honey that is typically provided in mass‐rearing programs. Certain of the flower species Bidens alba (L.), Spermacoce verticillata L., Lobularia maritima (L.) Desv., Brassica nigra (L.), Lantana camara L., their nectar or pollen, provided a diet that resulted in longer maximum life spans than water alone. Unlike some tephritid flies, the braconid did not feed on fresh bird feces or leaf‐surface exudates. Feeding by D. longicaudata on wounded host fruits of tephritid flies suggests that adult parasitoids would not need separate forays for adult food and oviposition sites, as these occur in the same locations. We conclude that an inventory of adult foods may help target inundative releases of D. longicaudata and lead to improvements in diets used for mass rearing.     

Modification of alternan by dextranase

Alternan is a unique glucan with a backbone structure of alternating α-(1 → 6) and α-(1 → 3) linkages. Previously, we isolated strains of Penicillium sp. that modify native, high molecular weight alternan in a novel bioconversion process to a lower molecular weight form with solution viscosity properties similar to those of commercial gum arabic. The mechanism of this modification was unknown. Here, we report that these Penicillium sp. strains secrete dextranase during germination on alternan. Furthermore, alternan is modified in vitro by commercial dextranases, and dextranase-modified alternan appears to be identical to bioconversion-modified alternan. This is surprising, since alternan has long been considered to be resistant to dextranase. Results suggest that native alternan may have localized regions of consecutive α-(1 → 6) linkages that serve as substrates for dextranase. Dextranase treatment of native alternan, particularly with GRAS enzymes, may have practical advantages for the production of modified alternan as a gum arabic substitute. U.S. Department of Agriculture—Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable.     

Plasma membrane H+-ATPase-dependent citrate exudation from cluster roots of phosphate-deficient white lupin

White lupin ( Lupinus albus L.) is able to grow on soils with sparingly available phosphate (P) by producing specialized structures called cluster roots. To mobilize sparingly soluble P forms in soils, cluster roots release substantial amounts of carboxylates and concomitantly acidify the rhizosphere. The relationship between acidification and carboxylate exudation is still largely unknown. In the present work, we studied the linkage between organic acids (malate and citrate) and proton exudations in cluster roots of P-deficient white lupin. After the illumination started, citrate exudation increased transiently and reached a maximum after 5 h. This effect was accompanied by a strong acidification of the external medium and alkalinization of the cytosol, as evidenced by in vivo nuclear magnetic resonance (NMR) analysis. Fusicoccin, an activator of the plasma membrane (PM) H⁺-ATPase, stimulated citrate exudation, whereas vanadate, an inhibitor of the H⁺-ATPase, reduced citrate exudation. The burst of citrate exudation was associated with an increase in expression of the LHA1 PM H⁺-ATPase gene, an increased amount of H⁺-ATPase protein, a shift in pH optimum of the enzyme and post-translational modification of an H⁺-ATPase protein involving binding of activating 14-3-3 protein. Taken together, our results indicate a close link in cluster roots of P-deficient white lupin between the burst of citrate exudation and PM H⁺-ATPase-catalysed proton efflux.     

Differential Secretion and Accumulation of Terpene Indole Alkaloids in Hairy Roots of <Emphasis Type="Italic">Catharanthus roseus</Emphasis> Treated with Methyl Jasmonate

The induction of several secondary metabolites in plants is one of the most commonly observed effects after the external addition of methyl jasmonate (MeJA). After the elicitation of Catharanthus roseus hairy roots with different concentrations of MeJA, changes in the accumulation of alkaloids such as ajmalicine, serpentine, ajmaline and catharanthine were observed. In addition to the increased accumulation of alkaloids in the tissues, the root exudation of phytochemicals increased compared to that of the non-treated control hairy roots. Moreover, MeJA induced differential secretion of several C. roseus hairy root metabolites.