Neotropical ant gardens

In ant gardens of lowland Amazonia, parabiotic ant speciesCamponotus femoratus andCrematogaster cf.limata parabiotica cultivate a taxonomically diverse group of epiphytic plants, whose establishment is restricted to arboreal carton ant nests. Epiphyte seeds are collected by workers ofCa. femoratus, the larger of the two ants, and stored unharmed in brood chambers where they subsequently germinate. Although seeds of some ant-garden epiphytes bear nutritional rewards, previous studies have shown that these rewards are not sufficient to explain the pattern of ant attraction to seeds. Five aromatic compounds occur frequently in and on the seeds of most ant-garden epiphytes and may be chemical cues by which ants recognize propagules of their symbiotic plants. The most widely distributed of these is methyl 6-methylsalicylate [6-MMS]1, previously reported as a major mandibular gland product in relatedCamponotus species and present in trace quantities inCa. femoratus males. (–)-Citronellol6 (previously unreported inCamponotus) was the principal volatile constituent in extracts of male heads, and (–)-mellein7 was present in small quantities. Discovery of 6-MMS inside the mandibular glands of maleCa. femoratus (and its presence in analogous glands of related ants) offers preliminary support for Ule's (1906) hypothesis that seeds attract ants by mimicking ant brood. In addition, the likely fungistatic activity of seed compounds suggests that they could retard microbial pathogens of ants and plants in the organic detritus of nest gardens. While the presence of identical seed compounds in so many unrelated plant lineages might represent a remarkable case of convergent evolution, other interpretations are possible.     

Characterization of aggregation factors and associated compounds from the argentine ant,Iridomyrmex humilis

(Z)-9-Hexadecenal (I), 13-(1-methylpropyl)tridecanolide (II), and (Z)-10-nonadecene-2-one (IV) have been characterized from a lipid fraction of the total extract ofI. humilis. Glycerides of normal fatty acids constitute the bulk of the lipid fraction. Compound I, a general aggregation factor ofI. humilis, is a constituent of the ventral gland secretion. Actinidine has been characterized from the pyrazine-containing fraction of the total extract.     

Constituents of mandibular and Dufour's glands of an australianPolyrhachis weaver ant

Worker ants ofPolyrhachis (Cyrtomyrma) ?doddi collectively discharge the secretions of their large mandibular glands when their nest is disturbed. The major glandular compounds of workers are 6-methylhept-5-en-2-one and phenylacetaldehyde oxime. Other components identified are mellein, 6-methylhept-5-en-2-one oxime, phenylacetonitrile, phenyiacetaldehyde, benzaldehyde, and several alkanes and alkenes. The mandibular gland secretions of queens differ from those of workers only quantitatively. Large queens have considerably more of most components, the small queens have much less of volatile components. There is a pronounced sexual difference: the major components of the male's secretions are octanoic acid and mellein, with geranic acid, 8-heptadecene, 2-methylbutanoic acid, and 9-nonadecene present in lesser amounts. Workers ofP. ?doddi also have unusually large Dufour's glands containing a large array of hydrocarbons, of which tridecane is the major component, but α-farnesene, pentadecane, and heptadecene are also present in large quantities.     

黄荆子中香豆素木脂素的分离及油脂抗氧化作用

应用油脂抗氧化活性导向,采用聚酰胺、硅胶等柱色谱从黄荆子提取物中分离得到两个化合物,经波谱分析结构鉴定为异嗪皮啶(Ⅰ)和3,4-二氢-6-羟基-4-(4-羟基-3-甲氧基苯基)-3-羟甲基-7-甲氧基-2-醛基萘(Ⅱ)。添加质量分数0.04%的异嗪皮啶(Ⅰ)在猪油中的抗氧化效果以及添加质量分数0.06%的3,4-二氢-6-羟基-4-(4-羟基-3-甲氧基苯基)-3-羟甲基-7-甲氧基-2-醛基萘(Ⅱ)在猪油中的抗氧化效果均比添加质量分数0.02%的2,6-二叔丁基-4-甲基苯酚(BHT)强,而且具有量效关系。     

C.I.分散红91的合成与应用

研究了以1-氨基-4-羟基-2-苯氧基蒽醌和己二醇为原料,在聚乙二醇溶剂中合成1-氨基-4-羟基-2-(6-羟基己氧基)蒽醌(C.I.分散红91)的工艺,获得较优合成工艺参数,产品总收率达85%,比文献值提高近10%。对合成的产品进行了结构表征与应用测试。     

A minor source of vernolic,malvalic, and sterculic acids inPithecollobium dulce (syn.Inga dulcis) seed oil

Pithecollobium dulce, Benth (syn.Inga dulcis, Willd) seed oil, belonging to the Leguminosae plant family, contains minor amounts of vernolic acid (12,13-epoxy-octadec-cis-9-enoic acid, 10.0%), malvalic acid [7-(2-octacyclopropen-1-yl)heptanoic acid, 3.2%], and sterculic acid [8-(2-octacyclopropen-1-yl)octanoic acid, 2.0%]. The other normal fatty acids are palmitic (12.1%), stearic (4.2%), behenic (10.6%), oleic (34.1%), and linoleic (23.8%). These fatty acids have been characterized by Fourier transform infrared,¹H nuclear magnetic resonance, mass spectrometry and gas-liquid chromatography techniques and by chemical degradations.     

Hydroxamic Acid Content and Toxicity of Rye at Selected Growth Stages

Rye (Secale cereale L.) is an important cover crop that provides many benefits to cropping systems including weed and pest suppression resulting from allelopathic substances. Hydroxamic acids have been identified as allelopathic compounds in rye. This research was conducted to improve the methodology for quantifying hydroxamic acids and to determine the relationship between hydroxamic acid content and phytotoxicity of extracts of rye root and shoot tissue harvested at selected growth stages. Detection limits for an LC/MS-MS method for analysis of hydroxamic acids from crude aqueous extracts were better than have been reported previously. (2R)-2-β-d-Glucopyranosyloxy-4-hydroxy-(2H)-1,4-benzoxazin-3(4H)-one (DIBOA-G), 2,4-dihydroxy-(2H)-1,4-benzoxazin-3(4H)-one (DIBOA), benzoxazolin-2(3H)-one (BOA), and the methoxy-substituted form of these compounds, (2R)-2-β-d-glucopyranosyloxy-4-hydroxy-7-methoxy-(2H)-1,4-benzoxazin-3(4H)-one (DIMBOA glucose), 2,4-hydroxy-7-methoxy-(2H)-1,4-benzoxazin-3(4H)-one (DIMBOA), and 6-methoxy-benzoxazolin-2(3H)-one (MBOA), were all detected in rye tissue. DIBOA and BOA were prevalent in shoot tissue, whereas the methoxy-substituted compounds, DIMBOA glucose and MBOA, were prevalent in root tissue. Total hydroxamic acid concentration in rye tissue generally declined with age. Aqueous crude extracts of rye shoot tissue were more toxic than extracts of root tissue to lettuce (Lactuca sativa L.) and tomato (Lycopersicon esculentum Mill.) root length. Extracts of rye seedlings (Feekes growth stage 2) were most phytotoxic, but there was no pattern to the phytotoxicity of extracts of rye sampled at growth stages 4 to 10.5.4, and no correlation of hydroxamic acid content and phytotoxicity (I₅₀ values). Analysis of dose–response model slope coefficients indicated a lack of parallelism among models for rye extracts from different growth stages, suggesting that phytotoxicity may be attributed to compounds with different modes of action at different stages. Hydroxamic acids may account for the phytoxicity of extracts derived from rye at early growth stages, but other compounds are probably responsible in later growth stages.