Effects of a foliar fertilizer containing boron on the development of Sclerotinia stem rot (Sclerotinia sclerotiorum) on canola (Brassica napus L.) leaves

Sclerotinia stem rot (Sclerotinia sclerotiorum Lib. De Bary) is one of the most destructive fungal diseases on canola (Brassica napus L.). The effect of a foliar fertilizer containing 3% boron (Active Flower™ [AF]) in reducing disease severity was evaluated. AF at 0.1, 0.3 and 0.5 ml/100 ml was first tested for growth inhibition of S. sclerotiorum in potato dextrose broth. Growth was reduced at 0.5 ml/100 ml by around 90%. Boric acid (BA), an important component of AF, was tested against fungal growth at 10 ml/L, and no significant effect (p = .05) was found. Foliar applications of AF and AF formulation that did not contain boron at 0.1, 0.3 and 0.5 ml/100 ml were made weekly to canola ‘Westar’ grown under greenhouse conditions. Treatments were also made with BA at 10 ml/L to canola plants. After four applications, AF at 0.5 ml/100 ml and BA at 10 ml/L enhanced boron levels in leaves by fivefold and threefold, respectively, compared with the control. Lesion size of S. sclerotiorum on detached leaves was significantly (p < .05) reduced by AF at 0.5 ml/100 ml, but lesion size was not reduced on AFWB-treated leaves. Experiments were repeated twice with the same results. Levels of phenolic compounds in leaves treated with 0.5 ml/100 ml AF were enhanced by twofold compared with the control. There were no significant differences in lignin, peroxidase (POD) or polyphenoloxidase (PPO) between the control and AF treatments. These results suggest that enhanced boron levels in canola leaves were associated with a suppressive effect on disease due to S. sclerotiorum.     

X-ray absorption fine structure study of the atomic and electronic structure of molybdenum disulfide intercalation compounds with transition metals

The local structures of ‘host’ and ‘guest’ layers of MoS₂ intercalated with M(OH)₂ (M=Mn, Co and Ni) prepared via interaction of single-layer MoS₂ dispersions and solutions of M²⁺ salts were studied by X-ray absorption spectroscopy. According to M K-edge extended X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) results, the electronic structure and atomic environment of the M atoms in the intercalates are similar to that of the crystalline hydroxides M(OH)₂. In the Ni intercalate, Mo K-edge EXAFS revealed a structural change of the ‘host’ MoS₂ layers similar to that reported for water dispersions of MoS₂ single layers. S K-edge XANES data indicate that the change is associated with increased electron density on the S atoms in the matrix. SO₄²⁻ and Mo″⁻ (4 < n < 6) were detected in the intercalated materials exposed to air, suggesting that transition metal intercalation may increase the susceptibility of the MoS₂ layers to oxidation.     

The impact of plant secondary compounds on primate feeding behavior

The recent literature on plant secondary compounds and their influence on primate feeding behavior is reviewed. Many studies of nonhuman primates document the extreme selectivity that primates, particularly herbivorous species, demonstrate in their food choice. Until quite recently investigators interpreted this to mean that herbivorous primates were not food limited. This view has been challenged in the past 10 years by researchers concentrating on the primate–plant interaction. Chemical analyses have demonstrated that plant parts are of varying quality due to differences in nutrient and secondary compound content. The assumption that all leaves (or fruits, flowers, and insects) are potential foods of equal value to the primates eating them is refuted. The observed selectivity and preferences of primates for specific plant or insect species and parts are now viewed as strategies for dealing with the nutrient and secondary compound content variation in these foods.     

美凤蝶成虫虫体挥发物的主要成分与变化动态研究

挥发物在蝴蝶种内识别、交配繁衍等过程中作用关键。本文旨在研究美凤蝶Papilio memnon成虫虫体挥发物的变化规律,为下一步探索蝴蝶虫体挥发物作为嗅觉信号的组成成分在求偶过程中的作用提供基础资料。应用固相微萃取方法分别收集美凤蝶雌雄成虫的虫体挥发物,用GC-MS（气相色谱-质谱）技术对挥发物进行分析和比较。结果显示,羽化后的雌雄蝶可检测到烷烃类、烯烃类、炔烃类、芳香类、醇类、醛类、酯类、酸类等12类挥发物,其中芳香类、酯类、酸类在羽化后均有出现。交配前,雌雄蝶挥发物分别有14种和16种,其中14种为共有,而以反-2-辛烯醛（雌：59.88%,雄：77.99%）和2-甲基烯丙醇（雌：14.47%,雄：8.42%）相对含量较高。交配时,雌雄蝶挥发物分别增加到24种和21种,其中20种为共有,优势挥发物除反-2-辛烯醛（雌：53.75%,雄：39.62%）和2-甲基烯丙醇（雌：9.36%,雄：11.04%）外,还包括1-二十醇（雌：10.46%,雄：21.13%）。另外,雌蝶交配时有4种特有挥发物（1-茚酮、异辛酸、1-苯基-1-丙炔、紫苏醛）,而雄蝶仅1种（β-石竹烯）。然而,一旦交配后,以上优势挥发物与交配时雌雄蝶特有挥发物均未检测到。推测2-甲基烯丙醇、反-2-辛烯醛和1-二十醇可能在美凤蝶种内识别过程中发挥作用,而1-茚酮、异辛酸、1-苯基-1-丙炔、紫苏醛和β-石竹烯则可能在求偶交配期间具有增强雌雄个体识别或相互吸引等作用。     

Manganese and fungal pathogens: Metabolism and potential association with virulence

Nutritional immunity is one of the strategies employed by the host to combat invading pathogens. It consists of actively controlling micronutrient bioavailability in the site of infection to hinder microbial growth. The role of manganese in cell biology and nutritional immunity for bacterial pathogens is well understood, but data regarding fungi are still limited. Fungi have evolved complex regulatory systems to acquire, distribute, and utilize manganese. Therefore, the disruption of manganese homeostasis in pathogenic fungi may lead to severe phenotypes and impact virulence. Because the host presents tools for manganese sequestration, and this condition can reduce the growth of important fungal pathogens such as Candida albicans, Aspergillus fumigatus, and Cryptococcus neoformans, it is feasible to suppose that manganese nutritional immunity could play an important role in fungal infections. However, direct evidence is still lacking, and little is known about manganese homeostasis, nutritional immunity, and specific adaptations in individual species of fungal pathogens. In this opinion, we present the current body of knowledge about these subjects, arguing about manganese importance in host–pathogen interactions.     

Limonoids from the bark of Toona ciliata var pubescens and their anti-tumor activities

Two previously undescribed B-ring seco-limonoids named toonacilinatin I (1) and toonacilinatin J (2), together with ten known analogues (3–12), were isolated from the ethyl acetate extract of the bark of Toona ciliata var pubescens. All structures were elucidated by extensive spectroscopic analysis involving IR, MS, and NMR. Among them, compounds 1–10, and 12 were discovered from this plant for the first time. All the compounds except 7 and 8 were evaluated for their anti-tumor activity by MTT method of MDA-MB-231 and A-673 cell lines, the bioassay results showed that compounds 1, 2, 5, 9 and 11 exerted superior inhibitory activity with IC₅₀ values as 0.11–1.60 μM. Notably, those active compounds exhibited little effect on normal hepatocellular HL-7702 cells.     

Two new sesquiterpenoids and one new p-coumaroyl-triterpenoid derivative from Myrcia guianensis

Two new sesquiterpenoids (1 and 2) and one new p-coumaroyl-triterpenoid derivative (3), along with five known sesquiterpenoids (4–8), seven triterpenoids (9–15), and two steroids (16 and 17) were isolated from Myrcia guianensis. Compound 1 [6-methyl-5-(2-hydroxy-3-chloro-5-methyl phenyl)-heptan-2-one] contains a chlorine atom attached to C-10, which seems to be the first report of a chlorine-containing sesquiterpenoid in the Myrtaceae family. The biogenesis of the two new sesquiterpenoids (1 and 2) are proposed herein, whereas the isolation of these sesquiterpenoids and triterpenoids from M. guianensis may present chemophenetic relevance to consolidate the genus Myrcia within the Myrtaceae family.     

HS-SPME-GC-MS法分析3种块菌子囊果主要挥发性成分

本研究采用顶空-固相微萃取结合气相色谱-质谱联用技术(HS-SPME-GC-MS)比较分析了假喜马拉雅块菌Tuber pseudohimalayense、中华夏块菌T. sinoaestivum和印度块菌T. indicum子囊果主要挥发性有机化合物(volatile organic compounds,VOCs)组成与含量。结果表明,在3种块菌子囊果中共鉴定到173种VOCs,其中假喜马拉雅块菌、中华夏块菌和印度块菌子囊果中分别检测到79、63和71种挥发性成分,3种块菌子囊果中共有成分11种,其中1-辛烯-3-醇是含量最高的共有化合物(39.52%、38.98%和8.46%)。利用挥发性成分对3种块菌种类进行判别分析,结果表明2-丁酮、庚醛、苯乙烯、1-辛烯-3-醇和环十四烷能100.0%地将3种块菌样品按照种类正确分类。本研究初步确定了3种块菌子囊果VOCs组成和含量的差异,并探究了用VOCs相对含量区分3种块菌种类的可行性,为我国块菌质量评价,尤其是加工的块菌商品的鉴别提供了重要的理论依据。