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.     

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.     

Semen cryopreservation in golden‐headed lion tamarin,Leontopithecus chrysomelas

Wild animal genetic resource banking (GRB) represents a valuable tool in conservation breeding programs, particularly in cases involving endangered species such as the golden‐headed lion tamarin (Leontopithecus chrysomelas). Thus, we aimed to assess a sperm freezing protocol for golden‐headed lion tamarins using two different exenders: BotuBOV® (BB) and Test Yolk Buffer® (TYB). Ejaculates were collected by penile vibrostimulation from animals housed at São Paulo Zoological Park Foundation, São Paulo, Brazil, and after immediate analysis, two aliquots were diluted in BB and TYB. Postthawing samples were evaluated for total and progressive motility, plasma membrane and acrosome integrities, mitochondrial activity, susceptibility to oxidative stress, and sperm–egg‐binding. No differences between BB and TYB were found for most seminal parameters, except for acrosome integrity and susceptibility to oxidative stress (in both cases BB showed higher values). However, in spite of these differences and regardless of the extender used, postthaw sperm motility and viability with the described protocol were encouraging (on average >50% and >80%, respectively), indicating that sperm cryopreservation may be a short‐term measure for the conservation of golden‐headed lion tamarins.     

Retinal spreading depression and the extracellular milieu

We used isolated chick retina in vitro to study the participation of the extracellular milieu in the occurrence and propagation of spreading depression. The propagation was followed by visual observation or microphotometry and the ionic changes in the extracellular compartment were recorded with double-barreled ion-selective microelectrodes. The front of the spreading wave is accompanied by increased light scattering in the tissue and by decrease of Cl-, Na+, and Ca2+, increase of K+, and an alkaline-acid shift in the extracellular space, concomitant with the slow voltage changes characteristic of the wave. As the spread is related to the chemical steady-state of the extracellular milieu, the velocity of propagation is influenced by a balanced interplay of the chemical constituents of the superfusing solution, e.g., K+, HCO-3, and glucose facilitate, while Cl- and Mg2+ hinder the wave. Steady-state alterations induced by physical factors (temperature) or related to experimental conditions (speed and direction of superfusate flow) change markedly the velocity of propagation. Generally the procedures that cause increase of velocity augment the susceptibility of the preparation to the reaction and eventually may trigger it. Propagated spreading depression is considered as a chemical diffusion reaction pervading more intensively the inner plexiform layer of the retina.     

A detailed study of the periodate oxidation of sialic acids in glycoproteins

Periodate oxidation of terminalN-acetyl- andN-glycoloylneuraminic acid residues in the mucins from edible bird nest substance and pig submandibular gland, respectively, can be carried out under conditions which exclusively give rise to the formation of the C-7 analogues of these sialic acids. In contrast, the C-8 compounds can be obtained in a maximum yield of about 40%. Under identical conditions,N-glycoloylneuraminic acid is oxidized about 1.5 times faster than theN-acetylated derivative. After release of the sialic acids by acid hydrolysis, the characterization of the oxidation products was carried out by TLC, by GLC and GLC-MS of the corresponding pertrimethylsilyl derivatives, and by 500-MHz¹H-NMR spectroscopy. In addition, molar response factors for GLC analysis and extinction coefficients in the orcinol/Fe³⁺/HCl assay were determined.     

Re-examination of the putative roles of insulin and prolactin in the regulation of lipid deposition and lipogenesis in vivo in mammary gland and white and brown adipose tissue of lactating rats and litter-removed rats.

1. The effects of various treatments to alter either plasma prolactin (bromocryptine administration or removal of litter) or the metabolic activity of the mammary gland (unilateral or complete teat sealing) on the disposal of oral [14C]lipid between 14CO2 production and [14C]lipid accumulation in tissues of lactating rats were studied. In addition, the rates of lipogenesis in vivo were measured in mammary gland, brown and white adipose tissue and liver. 2. Bromocryptine administration lowered plasma prolactin, but did not alter [14C]lipid accumulation in mammary gland or in white and brown adipose tissue. 3. In contrast, complete sealing of teats results in no change in plasma prolactin, but a 90% decrease in [14C]lipid accumulation in mammary gland and a 4-fold increase in white and brown adipose tissue. The rate of lipogenesis in mammary gland was decreased by 95%, but there was no change in the rate in white and brown adipose tissue. Unilateral sealing of teats resulted in a decrease in [14C]lipid accumulation in white adipose tissue. 4. Removal of the litter for 24 h (low prolactin) produced a similar pattern to complete teat sealing, except that there was a 6-fold increase in lipogenesis in white adipose tissue. Re-suckling for 5 h increased plasma prolactin, but did not alter the response seen in litter-removed lactating rats. 5. Changes in lipoprotein lipase activity and in plasma insulin paralleled the reciprocal changes in [14C]lipid accumulation in white and brown adipose tissue and in mammary gland. 6. It is concluded that the plasma insulin is more important than prolactin in regulating lipid deposition in adipose tissue during lactation, and that any effects of prolactin must be indirect.     

Four new species of yeast isolated from insect frass in bark ofTsuga heterophylla (Raf.) Sargent

Summary In a study of the yeasts associated with insect frass underneath the bark ofTsuga heterophylla (the Pacific Coast hemlock) four new species of yeast were found. These were described asSporobolomyces singularis, Bullera tsugae, Cryptococcus skinneri andCandida oregonensis. Sporobolomyces singularis is a non-pigmented species, which required an amendment of the genus definition. Ballistospore formation of the new species ofSporobolomyces and ofBullera was absent on malt agar and on potato glucose agar, but positive on corn meal agar. An unusual case of quantitative transgalactosylation by growing cells ofSporobolomyces singularis on lactose has been described. It has been proposed to establish a “Candida parapsilosis Group” of species to whichC. oregonensis was assigned. Supported by a fellowship of the Calouste Gulbenkian Foundation, Lisbon, Portugal.     

A new transthyretin mutation associated with amyloid cardiomyopathy.

In transthyretin (TTR) a new mutation (TTR-Thr45) has been identified in a patient with familial amyloidosis characterized clinically by prominent cardiomyopathy and the absence of peripheral neuropathy. Comparative peptide mapping by high-performance liquid chromatography of the patient's plasma TTR together with normal TTR showed the presence of an abnormal tryptic peptide in the patient's TTR. The sequence of this peptide (peptide 6, residues 36-48) demonstrated the presence of a threonine-for-alanine substitution at position 45. This change can be explained by a single base change of adenine for guanine in the Ala-45 codon and was demonstrated directly by DNA sequence analysis of PCR-amplified exon 2 of the TTR gene; allele-specific oligonucleotide hybridization both in the patient and in fixed heart tissue from his aunt confirmed the base change. The TTR-Thr45 mutation is a new variant TTR found associated with cardiomyopathy.     

Patterns of divergence during evolution of alpha 1-proteinase inhibitors in mammals

alpha 1-Proteinase inhibitor (alpha 1-PI), a member of the serine proteinase inhibitor superfamily, has a primary role in controlling neutrophil elastase activity within the mammalian circulation. Several studies have indicated that the reactive center region of alpha 1-PI, the amino acid sequence of which is critical to recognition of and binding to target proteinases, is highly divergent within and among species. This appears to be a consequence of accelerated rates of evolution that may have been driven by positive Darwinian selection. In order to examine this and other features of alpha 1-PI evolution in more detail, we have isolated and sequenced cDNAs representing alpha 1- PI mRNAs of the mouse species Mus saxicola and Mus minutoides and have compared these with a number of other mammalian alpha 1-PI mRNAs. Relative to other mammalian mRNAs, the extent of nonsynonymous substitution is generally high throughout the alpha 1-PI mRNA molecule, indicating greater overall rates of amino acid substitution. Within and among mouse species, the 5'-half of the mRNA, but not the 3'-half, has been homogenized by concerted evolution. Finally, the reactive center is under diversifying or positive Darwinian selection in murid rodents (rats, mice) and guinea pigs yet is under purifying selection in primates and artiodactyls. The significance of these findings to alpha 1-PI function and the possible selective forces driving evolution of serpins in general are discussed.