Antimicrobial and antiviral activities of an actinomycete (Streptomyces sp.) isolated from a Brazilian tropical forest soil

A promising producer of bioactive compounds isolated from a Brazilian tropical soil was tested for its range of antimicrobial activities. Strain 606, classified as Streptomyces sp., could not be identified up to species level, suggesting a possible new taxon. The supernatant and 10 extracts and fractions, obtained by extraction and chromatographic techniques, presented antimicrobial activity using antibiograms. The methanolic fraction was highly active against pathogenic bacteria, phytopathogenic fungi and the human pathogenic yeast Candida albicans. It also possessed high antiviral activity inhibiting the propagation of an acyclovir-resistant herpes simplex virus type 1 strain on HEp-2 cells at non-cytotoxic concentration. The strong cytotoxic effect suggests an antitumour action. This revised version was published online in August 2006 with corrections to the Cover Date.     

Structure–antimicrobial activity of some natural isocoumarins and their analogues

Three naturally occurring isocoumarins (paepalantine, paepalantine 9-O-beta-D-glucopyranoside and paepalantine 9-O-beta-D-allopyranosyl(1 --> 6) glucopyranoside) and two semi-synthetic analogues, 9,10-acylated compound and 9-OH-10-methylated compound, structurally similar to paepalantine, were evaluated for antimicrobial activity using a spectrophotometric microdilution technique. The paepalantine was active against S. aureus, S. epidermidis, and E. faecalis while the other four compounds proved ineffective against all microorganisms tested at concentrations of 500 microg/ml. Variations in phenolic substitution at OH-9 and/or OH-10 in the paepalantine molecule resulted in compounds without antimicrobial activity. A combination of structural features, two phenolic groups as cathecolic system, forms an oxygenated system arrangement that may reflect the potentially antimicrobial properties of paepalantine.     

Isolation of fungi from bats of the Amazon basin

A total of 2,886 bats captured in the Amazon Basin of Brazil were processed for the isolation of fungi. From the livers, spleens, and lungs of 155 bats (5.4%), 186 fungal isolates of the genera Candida (123 isolates), Trichosporon (26 isolates), Torulopsis (25 isolates), Kluyveromyces (11 isolates), and Geotrichum (1 isolate) were recovered. Seven known pathogenic species were present: Candida parapsilosis, C. guilliermondii, C. albicans, C. stellatoidea, C. pseudotropicalis, Trichosporon beigelii, and Torulopsis glabrata. Twenty-three culture-positive bats showed identical fungal colonization in multiple organs or mixed colonization in a single organ. The fungal isolation rates for individual bat species varied from 1 fungus per 87 bats to 3 fungi per 13 bats, and the mycoflora diversity for members of an individual fungus-bearing bat species varied from 16 fungi per 40 bats to 7 fungi per 6 bats. Of the 38 fungal species isolated, 36 had not been previously described as in vivo bat isolates. Of the 27 culture-positive bat species, 21 had not been previously described as mammalian hosts for medically or nonmedically important fungi.     

Measuring the heart rate of the spider, Aphonopelma hentzi: a non-invasive technique

In this work we describe a non‐invasive and precise technique to record the heartbeats of a spider. A linear output Hall effect transducer in conjunction with a small magnet was used to monitor the micromovements on the dorsal surface of the abdomen of the tarantula Aphonopelma hentzi (Girard) (Theraphosidae). The exoskeleton in this region is in direct contact with suspensory ligaments connected to the heart, and the dorsal cuticle of the opisthosoma moves with each heartbeat. The technique allowed the discrimination of the different stages of the spider's cardiac cycle. The method can be also adapted for a smaller spider or other arthropods. We believe that the method proposed in this paper allows investigators to gain insights into a spider's natural heart rate by gathering unbiased data with a non‐invasive and very precise technique. We have found the resting heart rate of A. hentzi to be 5.6 ± 1.47 beats/min, which is lower than previously reported values.     

Rediscovery of Anthias salmopunctatus Lubbock & Edwards, 1981, with comments on its natural history and conservation

After c. 30 years without sighting or capture, Anthias salmopunctatus was rediscovered at the type locality, St Peter and St Paul's Rocks, Mid-Atlantic Ridge. To date, the known distribution is restricted to depths varying from 35 to 55 m in vertical drop offs around the perimeter of the islands ( c. 400 m). This may be the smallest geographic range known for a marine fish species.     

Allogrooming, partner choice, and dominance in male anubis baboons

This study was designed to test the hypothesis that among unrelated male baboons (Papio cynocephalus anubis) in single-gender social groups there is no significant association between dominance status and allogrooming performance. The hypothesis was tested using behavioral measures obtained by focal animal sampling techniques. The results indicate that unrelated male baboons established well-defined linear dominance hierarchies, formed allogrooming relationships with one another, and exhibited a nonrandom distribution of allogrooming; however, there were no significant relationships between dominance rank and the frequency of allogrooming. We further tested our results by grouping individuals into three dominance status classes (high, middle, and low) and comparing the classes. Analysis of variance demonstrated no significant differences in rates of allogrooming by dominance class. These results suggest that dominance did not account for the variation in observed allogrooming behavior: Dominance status did not appear to determine the frequency with which animals groomed others, the number of grooming partners, or frequency of grooming that any individual received in comparison to that performed. High-ranking animals did not have significantly more grooming partners than low-ranking animals, and there appeared to be little competition within the groups for subordinates to groom high-ranking animals. When age, kinship, and group tenure are controlled, performance and reception of allogrooming are not strongly associated with dominance in single-gender social groups of male anubis baboons.     

Evaluation of strain competitiveness in Rhizobium leguminosarum bv phaseoli using a nod + fix− natural mutant

Competition from native soil rhizobia is likely to be an important factor limiting Phaseolus vulgaris L. inoculant response in Latin America. We used UMR 1116, a nod ⁺ fix^– natural mutant of Rhizobium leguminosarum bv phaseoli strain CC511, as a reference strain to study competition for nodulation sites in this species. When P. vulgaris cv Carioca was planted in soils containing different proportions of UMR 1116 and the effective and competitive strain UMR 1899, UMR 1116 occupied more than 50% of the nodules at all inoculant ratios tested, though increasing the proportion of UMR 1899 in the inoculant did enhance the number and percentage of effective nodules and plant dry weight. Sixty two strains of bean rhizobia were tested in competition with UMR 1116. An inoculant ratio of 1:1 was used, with all strains applied to the soil rather than to seeds. Strains varied in the number and percentage of effective nodules produced in competition with UMR 1116, and in plant dry weight, and there was a strong correlation between variation in each of these traits and plant N accumulation. Seven of the strains (UMR 1073, 1084, 1102, 1125, 1165, 1378 and 1384) were identified as both superior in competitive ability and active in N₂ fixation. Site of placement of the inoculant and ambient temperature influenced strain response.Journal paper 16736, Agricultural Experiment Station, University of Minnesota, St. Paul, MN 55108, USA