Chemotaxonomic relevance of cardenolides in Urginea fugax

In a chemotaxonomic approach the investigation of a methanolic extract of bulbs of Urginea fugax (MORIS) STEINH. resulted in the detection of several cardenolides. The structure of a novel compound, named fugaxin (1), was established as 12alpha,14beta-dihydroxy-2alpha,3beta-(tetrahydro-3',5'-dihydroxy-4'-methoxy-6'-methyl-2H-pyran-2',4'-diylbisoxy)-card-4,20-dienolide by extensive NMR spectroscopic studies including 2D-NMR techniques (COSY, HSQC, HMQC) and selective 1D experiments (NOE, TOCSY) as well as HR-ESI-MS. The chemotaxonomic relevance of the occurrence of cardenolides in the genus Urginea is discussed.     

Trichoderma spp. and Bacillus spp. as growth promoters in maize (Zea mays L.)

Microbes that are beneficial to plants are used to enhance the crop growth, yield and are alternatives to chemical fertilizers. Trichoderma and Bacillus are the predominant plant growth-promoting fungi and bacteria. The objective of this study was select, characterize, and evaluate isolates of Trichoderma spp. and Bacillus spp. native from the northern region of Sinaloa, Mexico, and assess their effect on growth promotion in maize (Zea mays L.). In greenhouse conditions, four Trichoderma isolates and twenty Bacillus isolates, as well as two controls, were tested in a completely randomized design with three replicates. We selected the two best strains of Trichoderma and Bacillus: TB = Trichoderma asperellum, TF = Trichoderma virens, B14 = Bacillus cereus sensu lato and B17 = Bacillus cereus, which were evaluated in the field in a completely randomized blocks in factorial arrangement design with three replicates applying different rates of nitrogen fertilizer (0, 150 kg N/ha, and 300 kg N/ha). Treatments 5 (B17 = B. cereus) and 11 (TF = T. virens) both fertilized with 150 kg N/ha showed similar yields and they did not reveal significant differences from the treatments fertilized with 300 kg N/ha. This indicated that treatment 5 (B17= B. cereus with 150 kg N/ha) and treatment 11 (TF= T. virens with 150 kg N/ha) were efficient as growth promoters, by not showing significant differences in root volume and dry weight of foliage. The results indicated a reduction of 50% in the rate of nitrogen to fertilizer required for maize (Zea mays L.) crops. These microorganisms Trichoderma and Bacillus could be an alternative to reduce the use of chemical fertilizers in maize.     

Biophysical investigation of human heparan sulfate D-glucosaminyl 3-O-sulfotransferase-3A: a mutual effect of enzyme oligomerisation and glycosaminoglycan ligand binding

3-O-sulfation of heparan sulfate (HS) is the rarest modification within heparan sulfate biosynthesis resulting in unique biological activities. Heparan sulfate d-glucosaminyl 3-O-sulfotransferase-3A (3-OST-3A) (EC 2.8.2.23) generates a binding site for the envelope glycoprotein D (gD) of herpes simplex virus 1. We have expressed the sulfotransferase domain of the human heparan sulfate 3-OST-3A isoform in Escherichia coli and subsequently purified the active enzyme which was found to be present as an oligomer under nonreducing conditions. The activity of the enzyme was tested by a novel gD-dependent gel mobility assay. A biophysical characterisation of 3-OST-3A was performed to study ligand binding and ligand-induced structural changes. Interestingly, the natural substrate HS did not cause a secondary structural change in the enzyme, whereas heparin and chondroitin sulfate did, both of which also exhibited similar high affinity binding to 3-OST-3A compared to HS as detected by isothermal fluorescence titrations. In cross-link assays, only HS was found to induce high molecular aggregates of 3-OST-3A whereas other GAG ligands did not or even inhibited enzyme oligomerisation like the K5 polysaccharide, which was nevertheless found to bind to the enzyme. We therefore conclude that since 3-OST-3A is able to bind also non-substrate GAG ligands with high affinity, discrimination among ligands is triggered by protein oligomerisation.     

The bromoperoxidase from the lichen Xanthoria parietina is a novel vanadium enzyme.

A novel bromoperoxidase was isolated from the lichen Xanthoria parietina. The enzyme contained vanadium, which is essential for enzymic activity. Under denaturating conditions the preparation showed a single protein band with an Mr of 65,000. Thermal-denaturation studies showed that this bromoperoxidase could tolerate high temperatures. The affinity of the enzyme for its substrate bromide is high; the Km for bromide was 29 microM. Excess halides (50 mM) inhibited enzymic activity considerably.     

Groundplan Anatomy of the Proboscis of Butterflies (Papilionoidea, Lepidoptera)

The anatomy of the proboscis was studied in representatives of all major subfamilies of Papilionoidea and several outgroup taxa which included Hesperiidae, Hedylidae and Geometroidea. In all species the cross-sectional outline of the tapering proboscis continuously changes from proximal to the tip while the central food canal, formed by the concave medial galeal walls, retains its oval shape. Each galea contains three types of muscles, a branching trachea, nerves, sensilla, and at least one longitudinal septum. We focused on the varying arrangement and distribution of the intrinsic galeal muscles from the basal galeal joint to the tip region. The plesiomorphic condition of the galeal composition of Papilionoidea is regarded to include one basal intrinsic muscle in the basal joint region and two series of intrinsic muscles, i.e. the lateral intrinsic galeal muscles and the median intrinsic galeal muscles, both series extending from the proximal region to the tip region. The plesiomorphic arrangements of the intrinsic muscle series are found in all representatives of Papilionidae, in one species of Lycaenidae (sensu lato), in many Nymphalidae (sensu lato), and in all outgroup species. Three apomorphic character states are distinguished regarding the presence and extension of the median intrinsic galeal muscles. (1) Present up to 35% of the proboscis length and absent distally in Pieridae, Lycaeninae (Lycaenidae), Satyrinae (Nymphalidae), and Danainae (Nymphalidae). (2) Present in the proximal third of the proboscis and again near the tip between 80 and 90% of the proboscis length in the examined Heliconiinae (Nymphalidae). (3) Completely absent, as in one lycaenid species from the subfamily Riodininae.     

The obstetrical dilemma hypothesis: there's life in the old dog yet

The term ‘obstetrical dilemma’ was coined by Washburn in 1960 to describe the trade-off between selection for a larger birth canal, permitting successful passage of a big-brained human neonate, and the smaller pelvic dimensions required for bipedal locomotion. His suggested solution to these antagonistic pressures was to give birth prematurely, explaining the unusual degree of neurological and physical immaturity, or secondary altriciality, observed in human infants. This proposed trade-off has traditionally been offered as the predominant evolutionary explanation for why human childbirth is so challenging, and inherently risky, compared to that of other primates. This perceived difficulty is likely due to the tight fit of fetal to maternal pelvic dimensions along with the convoluted shape of the birth canal and a comparatively low degree of ligamentous flexibility. Although the ideas combined under the obstetrical dilemma hypothesis originated almost a century ago, they have received renewed attention and empirical scrutiny in the last decade, with some researchers advocating complete rejection of the hypothesis and its assumptions. However, the hypothesis is complex because it presently captures several, mutually non-exclusive ideas: (i) there is an evolutionary trade-off resulting from opposing selection pressures on the pelvis; (ii) selection favouring a narrow pelvis specifically derives from bipedalism; (iii) human neonates are secondarily altricial because they are born relatively immature to ensure that they fit through the maternal bony pelvis; (iv) as a corollary to the asymmetric selection pressure for a spacious birth canal in females, humans evolved pronounced sexual dimorphism of pelvic shape. Recently, the hypothesis has been challenged on both empirical and theoretical grounds. Here, we appraise the original ideas captured under the ‘obstetrical dilemma’ and their subsequent evolution. We also evaluate complementary and alternative explanations for a tight fetopelvic fit and obstructed labour, including ecological factors related to nutrition and thermoregulation, constraints imposed by the stability of the pelvic floor or by maternal and fetal metabolism, the energetics of bipedalism, and variability in pelvic shape. This reveals that human childbirth is affected by a complex combination of evolutionary, ecological, and biocultural factors, which variably constrain maternal pelvic form and fetal growth. Our review demonstrates that it is unwarranted to reject the obstetrical dilemma hypothesis entirely because several of its fundamental assumptions have not been successfully discounted despite claims to the contrary. As such, the obstetrical dilemma remains a tenable hypothesis that can be used productively to guide evolutionary research.     

Antimycotic-antibiotic amphotericin B promotes influenza virus replication in cell culture

In general, antibiotics are not rated as substances that inhibit or support influenza virus replication. We describe here the enhancing effect of the polyene antibiotic amphotericin B (AmB) on influenza virus growth in Vero cells. We show that isolation rates of influenza A and B viruses from clinical samples can be dramatically enhanced by adding AmB to the culture medium. We demonstrate that AmB promotes the viral uptake and endocytic processing of the virus particles. This effect is specific for Vero and human nasal epithelial cells and was not observed in Madin-Darby canine kidney cells. The effect of AmB was subtype specific and more prominent for human seasonal influenza strains but absent for H5N1 human viruses. The AmB-enhancing effect seemed to be solely due to the viral hemagglutinin function. Our results indicate that the use of AmB may facilitate influenza virus isolation and production in Vero cells.     

Cardenolides from Adonis aestivalis.

Four cardenolides were isolated for the first time from the aerial parts of Adonis aestivalis. The compounds were identified by spectrometry and for 3-epi-periplogenin, helveticoside also by comparison with authentic substances. Two new cardenolides were structurally elucidated: strophanthidin-3-O-beta-D-digitoxosido-alpha-L-cymarosido-be ta-D-glucoside and strophanthidin-3-O-beta-D-digitoxosido-beta-D-digoxoside-bet a-D-diginosido-beta-D-glucoside.     

First description of mechanoreceptors in the corpus adiposum infrapatellare of man

The sensory innervation of the corpus adiposum infrapatellare of the human knee joint was studied by light microscopy. Small lamellated corpuscles (pacinian corpuscles) were found in the adipose tissue of the corpus adiposum infrapatellare. The lamellated corpuscles measured about 20 microns and consisted of 3-4 lamellae. It is discussed whether the corpus adiposum infrapatellare might perform a sensory function, influencing the muscle tone via polysynaptic reflexes.     

Purification and some characteristics of a non-haem bromoperoxidase from Streptomyces aureofaciens

A bromoperoxidase was isolated from the chlortetracycline-producing actinomycete, Streptomyces aureofaciens. This enzyme catalysed bromination and iodination, but surprisingly did not catalyse chlorination. The enzyme had an acidic pH optimum (pH 4.3) and the isoelectric point was 3.5. The Km for bromide was 20 mM and the Km for H2O2 was as high as 8 mM. The bromoperoxidase did not contain haem, since it was not inhibited by azide or cyanide. Excess bromide or chloride had no effect on its brominating activity; however, fluoride strongly inhibited the bromoperoxidase (Ki = 20 microM). On the basis of gel electrophoresis in the absence and presence of sodium dodecyl sulphate, the molecular mass of the enzyme was 65 kDa and it consisted of two subunits of 32 kDa each. The bromoperoxidase was remarkably thermostable.