Physicochemical and comparative properties of pectins extracted from Akebia trifoliata var. australis peel

The physicochemical properties of the pectins extracted from Akebia trifoliata var. australis peel with hydrochloric acid and citric acid, namely HEP and CEP, were evaluated as compared with citrus pectin (CP). X-ray diffraction confirmed that CP had more well defined crystal than HEP and CEP. The DE values of HEP, CEP and CP were 59.46%, 76.64% and 71.03%, respectively. CP exhibited the highest viscosity-average molecular weight of 64,848 Da, followed by HEP (45,353 Da) and CEP (28,877 Da). In general, the emulsion activity of HEP and CEP increased as oil concentration was increased, while HEP showed the strongest emulsion activity among the three pectins. Textural analysis demonstrated that the gelling properties of three pectins decreased with increase in pH, and CP displayed superiority in hardness (9.03 g), while CEP was the poorest (1.45 g). All results suggested that A. trifoliata var. australis had the potential in producing pectin for commercial food industry application.     

The chemotaxonomic and medicinal significance of phenolic acids in Arctopus and Alepidea (Apiaceae subfamily Saniculoideae)

The occurrence of (R)-3′-O-β-d-glucopyranosylrosmarinic acid, rosmarinic acid and caffeic acid in two important South African medicinal plants is reported for the first time. (R)-3′-O-β-d-Glucopyranosylrosmarinic acid and rosmarinic acid were isolated and identified in several samples from three species of the genus Arctopus L. (sieketroos) and three species of the genus Alepidea F. Delaroche (ikhathazo), both recently shown to be members of the subfamily Saniculoideae of the family Apiaceae. The compounds occur in high concentrations (up to 15.3 mg of (R)-3′-O-β-d-glucopyranosylrosmarinic acid per g dry wt) in roots of Arctopus. Our results provide a rationale for the traditional uses of these plants, as the identified compounds are all known for their antioxidant activity, with rosmarinic acid further contributing to a wide range of biological activities. Furthermore, we confirm the idea that (R)-3′-O-β-d-glucopyranosylrosmarinic acid is a useful chemotaxonomic marker for the subfamily Saniculoideae.     

Unusual iridoid glycosides in Veronica sects. Hebe and Labiatoides

In a chemosystematic investigation of three Southern hemisphere species of Veronica, namely the Australian Veronica derwentiana Andrews and Veronica perfoliata R.Br. (formerly Derwentia species), and the New Zealand Veronica catarractae G. Forster (formerly a species of Parahebe), the water-soluble constituents were isolated and identified by spectroscopic methods. Apart from other iridoid glucosides common to the genus, three unusual substituted benzoyl esters of aucubin (derwentiosides A–C) were obtained from V. derwentiana and a chlorinated iridoid glycoside (catarractoside) from V. catarractae in addition to other iridoids common to the genus. The chemical profile of V. perfoliata is similar to that of Northern hemisphere species of Veronica because of the presence of characteristic 6-O-catalpol esters. The profile of V. derwentiana is unique, since 6-O-esters of aucubin rather than of catalpol dominate, however, the acyl groups are the same as those present in catalpol esters found in some other Veronica sections. V. catarractae also contains one of the catalpol esters characteristic of Veronica, but in addition three 6-O-rhamnopyranosyl substituted iridoid glycosides, one of which is 6-O-rhamnopyranosylcatalpol. Esters of the latter compound are previously only known from the more derived species in recent phylogenetic trees of sect. Hebe to which V. catarractae now also belongs, but as a more basal member.     

Phenolic compounds in Hypericum species from the Trigynobrathys section

Phenolic compounds of thirteen Hypericum species growing in South Brazil were investigated aiming to evaluate the usefulness of their distribution as a taxonomic character. The HPLC analysis of the methanolic fractions displayed similar chemical profile and significant contents variation among the investigated taxa, being chlorogenic acid the main metabolite quantified in most of the species (ranging from traces to 16.65 mg% of extract), followed by hyperoside (between 0.27 and 11.48 mg%), quercitrin (0.09 and 13.34 mg%), guaijaverin (0.14 and 2.91 mg%) and isoquercitrin (0.14 and 6.97 mg%), whereas rutin and the xanthone mangiferin were not detected.     

Real Time PCR to detect and differentiate Campylobacter fetus subspecies fetus and Campylobacter fetus subspecies venerealis

Bovine venereal campylobacter infection, caused by Campylobacter fetus venerealis, is of significant economic importance to the livestock industry. Unfortunately, the successful detection and discrimination of C. fetus venerealis from C. fetus fetus continue to be a limitation throughout the world. There are several publications warning of the problem with biotyping methods as well as with recent molecular based assays. In this study, assessed on 1071 isolates, we report on the successful development of two Real Time SYBR® Green PCR assays that will allow for the detection and discrimination of C. fetus fetus and C. fetus venerealis. The sensitivity reported here for the C. fetus (CampF4/R4) and the C. fetus venerealis (CampF7/R7) specific PCR assays are 100% and 98.7% respectively. The specificity for these same PCR assays are 99.6% and 99.8% respectively.     

Rpi-blb2-mediated late blight resistance in Nicotiana benthamiana requires SGT1 and salicylic acid-mediated signaling but not RAR1 or HSP90

The Rpi-blb2 recognizes the presence of the Phytophthora infestans AVRblb2 and initiates effector-triggered immunity (ETI). We performed gain-of-function and loss-of-function studies in Nicotiana benthamiana to elucidate Rpi-blb2-mediated resistance to P. infestans. Rpi-blb2 triggered a hypersensitive response through SGT1-mediated, but not RAR-mediated or HSP90-mediated, pathways. NbSGT1 was also required for basal and ETI-mediated by Rpi-blb2 in N. benthamiana. Moreover, salicylic acid (SA) affected basal defense and Rpi-blb2-mediated resistance against P. infestans. The increased susceptibility of Rpi-blb2-transgenic plants in the NahG-background correlated with reduced levels of SA. These findings provide evidence for the roles of SGT1- and SA-signaling in Rpi-blb2-mediated resistance against P. infestans.     

Local immune response against larvae of Rhipicephalus (Boophilus) microplus in Bos taurus indicus and Bos taurus taurus cattle

Bos taurus indicus cattle are less susceptible to infestation with Rhipicephalus (Boophilus) microplus than Bos taurus taurus cattle but the immunological basis of this difference is not understood. We compared the dynamics of leukocyte infiltrations (T cell subsets, B cells, major histocompatibility complex (MHC) class II-expressing cells, granulocytes) in the skin near the mouthparts of larvae of R. microplus in B. t. indicus and B. t. taurus cattle. Previously naïve cattle were infested with 50,000 larvae (B. t. indicus) or 10,000 larvae (B. t. taurus) weekly for 6 weeks. One week after the last infestation all of the animals were infested with 20,000 larvae of R. microplus. Skin punch biopsies were taken from all animals on the day before the primary infestation and from sites of larval attachment on the day after the first, second, fourth and final infestations. Infiltrations with CD3⁺, CD4⁺, CD8⁺ and γδ T cells followed the same pattern in both breeds, showing relatively little change during the first four weekly infestations, followed by substantial increases at 7 weeks post-primary infestation. There was a tendency for more of all cell types except granulocytes to be observed in the skin of B. t. indicus cattle but the differences between the two breeds were consistently significant only for γδ T cells. Granulocyte infiltrations increased more rapidly from the day after infestation and were higher in B. t. taurus cattle than in B. t. indicus. Granulocytes and MHC class II-expressing cells infiltrated the areas closest to the mouthparts of larvae. A large volume of granulocyte antigens was seen in the gut of attached, feeding larvae.     

Prenylated acetophenones from Melicope obscura and Melicope obtusifolia ssp. obtusifolia var. arborea and their distribution in Rutaceae

Four prenylated acetophenones 2,6-dihydroxy-4-geranyloxyacetophenone (1), 4-geranyloxy-2,6,β-trihydroxyacetophenone (2), 2,6-dihydroxy-4-geranyloxy-3-prenylacetophenone (3), and 4-geranyloxy-3-prenyl-2,6,β-trihydroxyacetophenone (4) have for the first time been isolated from Melicope obscura (1 and 2) and Melicope obtusifolia ssp. obtusifolia var. arborea (3 and 4). The distribution of prenylated acetophenones in Rutaceae is reviewed and the results, including the new records, indicate that prenylated acetophenones are valuable as chemotaxonomic markers for the subfamily Rutoideae, tribe Xanthoxyleae sensu Engler.     

Septal pore complex morphology in the Agaricomycotina (Basidiomycota) with emphasis on the Cantharellales and Hymenochaetales

The ultrastructure of septa and septum-associated septal pore caps are important taxonomic markers in the Agaricomycotina (Basidiomycota, Fungi). The septal pore caps covering the typical basidiomycetous dolipore septum are divided into three main phenotypically recognized morphotypes: vesicular-tubular (including the vesicular, sacculate, tubular, ampulliform, and globular morphotypes), imperforate, and perforate. Until recently, the septal pore cap-type reflected the higher-order relationships within the Agaricomycotina. However, the new classification of Fungi resulted in many changes including revision of existing and addition of new orders. Therefore, the septal pore cap ultrastructure of more than 325 species as reported in literature was related to this new classification. In addition, the septal pore cap ultrastructures of Rickenella fibula and Cantharellus formosus were examined by transmission electron microscopy. Both fungi have dolipore septa associated with perforate septal pore caps. These results combined with data from the literature show that the septal pore cap-type within orders of the Agaricomycotina is generally monomorphic, except for the Cantharellales and Hymenochaetales.It appears from the fungal phylogeny combined with the septal pore cap ultrastructure that the vesicular-tubular and the imperforate type both may have arisen from endoplasmic reticulum. Thereafter, the imperforate type eventually gave rise to the perforate septal pore cap-type.     

Systematics and evolution of the genus Torrubiella (Hypocreales, Ascomycota)

Torrubiella is a genus of arthropod-pathogenic fungi that primarily attacks spiders and scale insects. Based on the morphology of the perithecia, asci, and ascospores, it is classified in Clavicipitaceae s. lat. (Hypocreales), and is considered a close relative of Cordyceps s. 1., which was recently reclassified into three families (Clavicipitaceae s. str., Cordycipitaceae, Ophiocordycipitaceae) and four genera (Cordyceps s. str, Elaphocordyceps, Metacordyceps, and Ophiocordyceps). Torrubiella is distinguished morphologically from Cordyceps s. lat. mainly by the production of superficial perithecia and the absence of a well-developed stipitate stroma. To test and refine evolutionary hypotheses regarding the placement of Torrubiella and its relationship to Cordyceps s. lat., a multi-gene phylogeny was constructed by conducting ML and Bayesian analyses. The monophyly of Torrubiella was rejected by these analyses with species of the genus present in Clavicipitaceae, Cordycipitaceae, and Ophiocordycipitaceae, and often intermixed among species of Cordyceps s. lat. The morphological characters traditionally used to define the genus are, therefore, not phylogenetically informative, with the stipitate stromata being gained and/or lost several times among clavicipitaceous fungi. Two new genera (Conoideocrella, Orbiocrella) are proposed to accommodate two separate lineages of torrubielloid fungi in the Clavicipitaceae s. str. In addition, one species is reclassified in Cordyceps s. str. and three are reclassified in Ophiocordyceps. The phylogenetic importance of anamorphic genera, host affiliation, and stipitate stromata is discussed.     

Polyunsaturated fatty acids cause apoptosis in C. albicans and C. dubliniensis biofilms

Background

Polyunsaturated fatty acids (PUFAs) have antifungal properties, but the mode by which they induce their action is not always clear. The aim of the study was to investigate apoptosis as a mode of action of antifungal PUFAs (stearidonic acid, eicosapentaenoic acid and docosapentaenoic acid) which are inhibitory towards biofilm formation of C. albicans and C. dubliniensis.

Methods

Candida biofilms were grown in the absence or presence of 1 mM PUFAs (linoleic acid, stearidonic acid, eicosapentaenoic acid, docosapentaenoic acid) for 48 h at 37 °C. The effect of these PUFAs on the membrane fatty acid profile and unsaturation index, oxidative stress, mitochondrial transmembrane potential and apoptosis was evaluated.

Results

When biofilms of C. albicans and C. dubliniensis were exposed to certain PUFAs there was an increase in unsaturation index of the cellular membranes and accumulation of intracellular reactive oxygen species (ROS). This resulted in apoptosis, evidenced by reduced mitochondrial membrane potential and nuclear condensation and fragmentation. The most effective PUFA was stearidonic acid.

Conclusions

The resultant cell death of both C. albicans and C. dubliniensis is due to apoptosis.

General significance

Due to the increase in drug resistance, alternative antifungal drugs are needed. A group of natural antifungal compounds is PUFAs. However, understanding their mechanisms of action is important for further use and development of these compounds as antifungal drugs. This paper provides insight into a possible mode of action of antifungal PUFAs.     

砷形态对黑藻和竹叶眼子菜有机酸含量的影响

采用室内溶液培养法,运用气相色谱-质谱联用(Gas chromatography-mass spectrometry,GC-MS)技术测定在As(Ⅲ)、As(Ⅴ)和二甲基胂酸(Dimethylarsinic acid,DMA)3种形态砷(浓度0—5.0 mg/L)胁迫下,砷超富集植物黑藻(Hydrilla verticillata(Linn.f.)Royle.)和非砷超富集植物竹叶眼子菜(Potamogeton malaianus Miq.)体内生成和体外分泌的7种有机酸的含量。结果表明,黑藻体内草酸、丙二酸、柠檬酸、苹果酸和棕榈酸都显著高于竹叶眼子菜(P<0.05)。在As(Ⅲ)处理时,黑藻体内柠檬酸、苹果酸、棕榈酸、亚麻酸和总有机酸显著下降,竹叶眼子菜棕榈酸显著下降;在As(Ⅴ)处理时,黑藻棕榈酸和总有机酸显著下降,竹叶眼子菜棕榈酸显著下降;在DMA处理时,黑藻草酸、柠檬酸和苹果酸显著下降,竹叶眼子菜棕榈酸、亚麻酸和总有机酸显著下降。黑藻在As(Ⅲ)处理下棕榈酸、亚麻酸、总有机酸和As(Ⅴ)处理下草酸含量与体内As含量呈显著负相关(P<0.05),而竹叶眼子菜在As(Ⅲ)或DMA处理下棕榈酸、亚麻酸、总有机酸含量以及在DMA处理下柠檬酸含量与体内As含量均呈显著负相关(P<0.05)。两种植物根系分泌物中均检测出草酸、丙二酸、琥珀酸和棕榈酸,但只有在As(Ⅲ)或As(Ⅴ)处理时黑藻分泌的草酸与体内As含量呈显著正相关。本研究表明As(Ⅲ)或As(Ⅴ)胁迫下黑藻向体外分泌草酸是其超富集砷的一种重要机制。     

Acid phosphatase in Enteromorpha

Extracts of the alga Enteromorpha linza hydrolysed glucose-6-phosphate, p-nitrophenylphosphate 2′-, 3′-, and 5′-adenosine monophosphates with an optimum at pH 5. Cytidine and uridine-5′-nucleoside diphosphates, and 2′-, and 3′-adenosine monophosphates were relatively poorly hydrolysed. Zn²⁺ (10 mM) inhibited the hydrolysis of all substrates, whereas Mg²⁺ (10 mM) may be stimulatory. It is suggested that the hydrolysis of these phosphomonoesters was due to the activity of a non-specific acid phosphatase (orthophosphoric monoester phosphohydrolase, E.C. 3.1.3.2).