Salt-tolerant phenol-degrading microorganisms isolated from Amazonian soil samples

Two phenol-degrading microorganisms were isolated from Amazonian rain forest soil samples after enrichment in the presence of phenol and a high salt concentration. The yeast Candida tropicalis and the bacterium Alcaligenes faecoalis were identified using several techniques, including staining, morphological observation and biochemical tests, fatty acid profiles and 16S/18S rRNA sequencing. Both isolates, A. faecalis and C. tropicalis, were used in phenol degradation assays, with Rhodococcus erythropolis as a reference phenol-degrading bacterium, and compared to microbial populations from wastewater samples collected from phenol-contaminated environments. C. tropicalis tolerated higher concentrations of phenol and salt (16 mM and 15%, respectively) than A. faecalis (12 mM and 5.6%). The yeast also tolerated a wider pH range (3-9) during phenol degradation than A. faecalis (pH 7-9). Phenol degradation was repressed in C. tropicalis by acetate and glucose, but not by lactate. Glucose and acetate had little effect, while lactate stimulated phenol degradation in A. faecalis. To our knowledge, these soils had never been contaminated with man-made phenolic compounds and this is the first report of phenol-degrading microorganisms from Amazonian forest soil samples. The results support the idea that natural uncontaminated environments contain sufficient genetic diversity to make them valid choices for the isolation of microorganisms useful in bioremediation.     

Structure and division of the Golgi complex in Trichomonas vaginalis and Tritrichomonas foetus.

We present observations on the fine structure and the division process of the Golgi complex in the protists Trichomonas vaginalis and Tritrichomonas foetus, parasites of the urogenital tract of humans and cattle, respectively. The Golgi in trichomonads is a prominent structure, associated with striated parabasal filaments to which this organelle seems to be connected. We followed by immunofluorescence and electron microscopy the Golgi in interphasic and mitotic cells. Ultrastructural studies were performed using fast-freezing fixation, immunocytochemistry using antisera to the known adhesins AP65 and AP51, cytochemistry (acid phosphatase, Ca++-ATPase, zinc iodide-osmium tetroxide technique (ZIO), for analysis of distribution of the endoplasmic reticulum and Golgi complex, and Thiéry's techniques), routine and serial thin-sections. Three-dimensional reconstruction, NBD-ceramide, fluorescent lectin (WGA) and nocodazole treatments were also used. We demonstrate that: (1) the Golgi in trichomonads is a single-copy organelle; (2) presents a fenestrated structure; (3) is formed by 8-12 saccules; (4) is connected to the parabasal filaments by thin filamentous bridges; (5) by cytochemistry, presents a positive reaction for the lectin WGA, Ca++-ATPase, acid phosphatase, ZIO and Thiéry's techniques; (6) does not appear to break down at any point of the cell cycle; (7) elongates during the cell cycle by lateral growth; (8) is labeled by anti-glutamylated tubulin antibodies, but it is not fragmented by nocodazole treatment; (9) before mitosis, the already elongated Golgi ribbon undergoes progressive medial fission, cisternae by cisternae, starting at the cisternae adjacent to the cell surface and ending with the cis-most cisternae; (10) the Golgikinesis originates two small Golgi ribbons; (11) the Golgi is intensely labeled with the antisera to the AP65 and AP51 adhesins in T. vaginalis, thus seeming to be a key station in the production of adhesins.     

Genetic variation in remnant populations of Dalbergia nigra (Papilionoideae), an endangered tree from the Brazilian Atlantic Forest

BACKGROUND AND AIMS: Dalbergia nigra, known as Brazilian rosewood, is an endangered tree species restricted to the Brazilian Atlantic Forest and has been intensively logged for five centuries due to its high-quality wood. The objective of the present study was to assess the genetic variation and structure in adults and saplings of the species from a large reserve of the Atlantic Forest, the Rio Doce State Park, and from two small surrounding fragments, one better preserved and another with a high degree of anthropogenic disturbance. METHODS: Analyses of genetic variation and structure were conducted by studying allozyme markers. Seven putative enzymatic loci were resolved, five of them being polymorphic. KEY RESULTS: The mean numbers of alleles per locus (A) were 1.93 and 1.73, while the percentages of polymorphic loci (P) were 93 and 73 % for adults and saplings, respectively. Saplings from the fragment with high anthropogenic disturbance exhibited the lowest values of A and P. The fragment that constitutes a conservation area exhibited genetic variation similar to the population from the large reserve. The observed (H(o)) and expected (H(e)) heterozygosities were not significantly different among the three populations. Only sapling populations showed F(ST) values (divergence among populations) significantly different from zero over all studied loci. The fragment with high anthropogenic disturbance exhibited considerable genetic divergence in relation to the above-cited populations. CONCLUSIONS: The evaluated populations displayed mean levels of genetic variation intermediate to those expected for narrow and widespread species. The results suggest that fragments with similar area and geographical distance from a large protected reserve can exhibit different levels of genetic variation, depending on the degree of anthropogenic disturbance. The considerable genetic variation in the protected fragment points to the importance of adequate conservation of small fragments for the preservation of genetic variation in D. nigra.     

Propolis: anti-Staphylococcus aureus activity and synergism with antimicrobial drugs

Propolis is a natural resinous substance collected by bees from tree exudates and secretions. Its antimicrobial activity has been investigated and inhibitory action on Staphylococcus aureus growth was evaluated. The in vitro synergism between ethanolic extract of propolis (EEP) and antimicrobial drugs by two susceptibility tests (Kirby and Bauer and E-Test) on 25 S. aureus strains was evaluated. Petri dishes with sub-inhibitory concentrations of EEP were incubated with 13 drugs using Kirby and Bauer method and synergism between EEP and five drugs [choramphenicol (CLO), gentamicin (GEN), netilmicin (NET), tetracycline (TET), and vancomycin (VAN)] was observed. Nine drugs were assayed by the E-test method and five of them exhibited a synergism [CLO, GEN, NET, TET, and clindamycin (CLI)]. The results demonstrated the synergism between EEP and antimicrobial drugs, especially those agents that interfere on bacterial protein synthesis.     

Prevalence of diarrheagenic Escherichia coli in children with diarrhea in Salvador, Bahia, Brazil

We report the frequency of the different diarrheagenic Escherichia coli (DEC) categories isolated from children with acute endemic diarrhea in Salvador, Bahia. The E. coli isolates were investigated by colony blot hybridization with the following genes probes: eae, EAF, bfpA, Stx1, Stx2, ST-Ih, ST-Ip, LT-I, LT-II, INV, and EAEC, as virulence markers to distinguish typical and atypical EPEC, EHEC/STEC, ETEC, EIEC, and EAEC. Seven of the eight categories of DEC were detected. The most frequently isolated was atypical EPEC (10.1%) followed by ETEC (7.5%), and EAEC (4.2%). EHEC, STEC, EIEC, and typical EPEC were each detected once. The strains of ETEC, EAEC, and atypical EPEC belonged to a wide variety of serotypes. The serotypes of the others categories were O26:H11 (EHEC), O21:H21 (STEC), O142:H34 (typical EPEC), and O:H55 (EIEC). We also present the clinical manifestations and other pathogenic species observed in children with DEC. This is the first report of EHEC and STEC in Salvador, and one of the first in Brazil.     

Three new species of Isospora schneider, 1881 (Apicomplexa: Eimeriidae) from the double-collared seed eater, Sporophila caerulescens (Passeriformes: Emberizidae), from Eastern Brazil

Three isosporan species are described from the double-collared seedeater, Sporophila caerulescens from Eastern Brazil. Isospora sporophilae n. sp. oocysts spherical to subspherical; oocyst wall bi-layered, smooth, inner layer colorless to pale yellowish, 21.6 x 20.9 (19.20-23.20 x 18.40-22.60) microm, shape-index 1.03 +/- 0.02 (1-1.10), with no micropyle or oocyst residuum. Polar bodies splinter-like or comma-like. Sporocysts ovoidal, 15.2 x 10.6 (17.40-12.80 x 12.60-8.40) microm, shape-index 1.43 +/- 0.14 (1.17-1.81), with knob-like Stieda body and residuum. Large crystalloid body in the center of the sporocyst. Isospora flausinoi n. sp. oocysts spherical to subspherical, oocyst wall bi-layered, smooth, colorless, 17.30 x 16.53 (14-20 x 13.60-20) microm, shape-index 1.05 +/- 0.04 (1-1.21). Micropyle and oocyst residuum absent; presence of a large polar body. Sporocystpiriform, 14.88 x 10.70 (11.80-18 x 8-12.40) microm, shape-index 1.40 +/- 0.18 (1.07-1.77), with smooth, thin, single-layered wall. Sporocyst with rounded Stieda body with no substieda body, and residuum composed of granular material. Isospora teixeirafilhoi n. sp. oocysts spherical to subspherical, oocyst wall bi-layered, smooth, colorless, 17.41 x 16.81 (15.60 - 19.40 x 14.20-18.80) microm. Shape-index 1.04 +/- 0.08 (1-1.12). Micropyle and oocyst residuum absent; presence of a small double-lobuled polar body. Sporocyst ovoid, 11.74 x 8.12 (9-14.20 x 6.20-9.40) microm. Shape-index 1.46 +/- 0.23 (1.06-1.88). Sporocyst with knob-like Stieda body, no sub-Stieda body and residuum composed of granular material.     

Reduction of myocardial infarct size by doxycycline: A role for plasmin inhibition

Myocardial ischemia-reperfusion (I/R) is associated with the activation of matrix metalloproteinases (MMPs) and serine proteases. We hypothesized that activation of MMPs and the serine protease plasmin contribute to early cardiac myocyte death following I/R and that broad-spectrum protease inhibition with doxycycline (DOX) preserves myocyte viability. Rats treated daily with or without DOX beginning 48 h prior to experimentation were subjected to 30 min of coronary occlusion and 2 days of reperfusion. DOX pre-treatment reduced infarct size by 37%. DOX attenuated increases in MMP-9 and plasmin levels as determined by gelatin zymography and immunoblot, respectively. Neutrophil extravasation was unaltered by DOX as assessed by myeloperoxidase (MPO) activity. To examine the contribution of MMP-9 and plasmin to myocyte injury, cultures of neonatal rat ventricular myocytes (NRVMs) were treated for 48 h with 83 kDa MMP-9 or plasminogen in the presence or absence of DOX. MMP-9 treatment did not affect myocyte viability. Plasminogen treatment led to increased plasmin activity, resulting in loss of ₁-integrin, NRVM detachment and apoptosis. DOX co-treatment inhibited plasmin activity and preserved NRVM attachment, whereas co-treatment with the broad-spectrum MMP inhibitor GM6001 had no effect. These results indicate that plasmin causes disruption of myocyte attachment and viability independently of MMP activation in vitro and that inhibition of plasmin by DOX may reduce I/R-induced myocyte death in vivo through the inhibition of plasmin. (Mol Cell Biochem 270: 1–11, 2005)     

Microscopical study of experimental wound healing in <Emphasis Type="Italic">Notothenia coriiceps</Emphasis> (Cabeçuda) at 0°C

Notothenia coriiceps (Cabeçuda) is an Antarctic benthic fish frequently found with lesions in the tegument caused by seal predation. We have investigated epidermal repair in these animals by means of a microscopic study of experimental wound healing at 0°C. At 24–48 h after wound induction, mucous exudate and necrotic lining cells covered the wound. At 7–14 days, an epidermal tongue could be discerned, folded at the tip, with intercellular oedema between the tip and the wound border. After 23–30 days, the wound was completely closed and the migrating epidermis, with intercellular oedema, was reduced. By 45–90 days, melanocytes progressively increased in the epidermis but no scales were formed. The inflammatory infiltrate was mainly composed of neutrophils after 7 days, at which time they were mostly replaced by macrophages; lymphocytes and plasma cells were also present. The border epidermis slid towards the centre, folding at the tip and finally fusing to form a diaphragm. The cells of the epidermis began to multiply only after complete closure of the wound. The lack of scale formation on induced and naturally found wounds, even after 90 days, suggests that different mechanisms in wound repair occur at 0°C from those in fish from temperate and tropical environment. This is the first report of successful wound repair at polar temperatures, indicating the adaptation of N. coriiceps to the Antarctic environment.The financial support from CNPq (68.0047/00-0 and 48.0262/00-4 grants), PROANTAR, SECIRM and FAPESP is greatly appreciated. Professor E.L. Cooper is partially supported by funds from the Hewlett Foundation to the Latin American Center, UCLA.     

Consequences of the Elimination of Old Leaves upon Spring Phenological Events and the New Leaves Nutrient Concentration in a Wintergreen Woody Species in the Southern Hemisphere

Previous studies analyzed the importance of old leaves conservancy for wintergreen species plant growth only after early spring old leaves elimination. However, carbon and nutrient resources for growth could have already been translocated from old leaves to shoots during autumn. In this work, the effect of old leaves absence on the leaf mass per area (LMA, g m⁻²) and nutrient concentration of new spring leaves, shoot growth, and flowering was studied in Aristotelia chilensis, an Andean Patagonic woody wintergreen species of Argentina. Plants were studied after autumn defoliation (AD) or late winter defoliation (WD) and results were compared to those of undamaged control plants (CO). The new leaves LMA and mineral nutrient (N, P, K, and Mg) concentration values did not decrease in AD or WD compared to CO plants. Conversely, CO plants showed higher flowering intensity and shoot lengthening compared to AD or WD plants. There were not remarkable differences regarding the defoliation time, though non-flowering shoots grew in a lesser degree than the flowering shoots in WD plants. It was concluded that A. chilensis old leaves cohort is an important source to shoot growth and flowering but their absence does not affect the new leaves structure or nutritional status from early spring in either AD or in WD plants. New leaves formation probably is guaranteed by resources (carbon and nutrients) previously stored in stems or even in the buds containing the preformed leaves since March, by the end of summer. Provided the availability of complete resources for the new leaf flush independently of the old leaves A. chilensis would restore the carbon balance as soon as possible to resume the growth of heterotrophic tissues at normal rates. Endogenous response to counterbalance the old leaves absence on non-flowering shoots was more effective when there was greater lag time between defoliation and shoot growth resume. Flowering and non-flowering shoots compete for the available resources when A. chilensis have not yet expanded leaves and shoots supporting reproductive structures were stronger sinks compared to non-flowering shoots in WD plants.