A new nematode species (Seuratoidea, Cucullanidae) parasitizing Parauchenipterus striatulus (Steindachner, 1876) (Pisces, Auchenipteridae) in Brazil

A new species of a cucullanid nematode is described, illustrated and compared with Cucullanus brevispiculus Moravec, Kohn & Fernandes, 1993 and C. rhamphichthydis Moravec, Kohn & Fernandes, 1997, two species previously reported as parasitizing freshwater fish in South America. The new species is characterized mainly by markedly short spicules, deirids and excretory pore situated posterior to the oesophago-intestinal junction, presence of strongly sclerotized plates in the oesophastome and oesophagus divided into two distinct portions.     

Implication of gene distribution in the bacterial chromosome for the bacterial cell factory

As bacterial genome sequences accumulate, more and more pieces of data suggest that there is a significant correlation between the distribution of genes along the chromosome and the physical architecture of the cell, suggesting that the map of the cell is in the chromosome. Considering sequences and experimental data indicative of cell compartmentalisation, mRNA folding and turnover, as well as known structural features of protein and membrane complexes, we show that preliminary in silico analysis of whole genome sequences strongly substantiates this hypothesis. If there is a correlation between the genome sequence and the cell architecture, it must derive from some selection pressure in the organisms growing in the wild. As a consequence, the underlying constraints should be optimised in genetically modified organisms if one is to expect high product yields. Consequences in terms of gene expression for biotechnology are straightforward: knocking genes out and in genomes should not be randomly performed, but should follow the rules of chromosome organisation.     

Mycoflora and mycotoxins in Brazilian black pepper,white pepper and Brazil nuts

A wide range of field and storage fungi were isolated from black pepper, white pepper and Brazil nut kernels from Amazonia. A total of 42 species were isolated from both peppers. Aspergillus flavus and A. niger were isolated more frequently from black than from white pepper. Other potential mycotoxigenic species isolated included: A. ochraceus, A. tamarii, A. versicolor, Emericella nidulans and Chaetomium globosum, Penicillium brevicompactum, P. citrinum, P. islandicum and P. glabrum. Species isolated from pepper for the first time were Acrogenospora sphaerocephala, Cylindrocarpon lichenicola, Lacellinopsis sacchari, Microascus cinereus, Petriella setifera and Sporormiella minima. Seventeen species were isolated from Brazil nut kernels. A. flavus was the dominant species followed by A. niger. P. citrinum and P. glabrum were the only penicillia isolated. Species isolated for the first time included Acremonium curvulum, Cunninghamella elegans, Exophiala sp., Fusarium oxysporum, Pseudoallescheria boydii, Rhizopusoryzae, Scopulariopsis sp., Thielavia terricola and Trichoderma citrinoviride. Considerably more metabolites were detected from black than white pepper in qualitative analyses. Chaetocin, penitrem A, and xanthocillin were identified only from black pepper, and tenuazonic acid was identified from both black and white pepper. Aflatoxin G₂, chaetoglobosin C, and spinulosin were identified from poor quality brazil nuts. Aflatoxin B₁ and B₂ were also only detected in poor quality brazil nuts at concentrations of 27.1 g kg^–1 and 2.1 g kg^–1 respectively (total 29.2 g kg^–1).This revised version was published online in October 2005 with corrections to the Cover Date.     

Cholesterol-lowering effects of dietary blue lupin (Lupinus angustifolius L.) in intact and ileorectal anastomosed pigs

The present study was undertaken to investigate the effect of cholesterol-enriched casein (CAS) and blue lupin seed (BL) diets on the cholesterol metabolism of intact (INT) and ileorectal anastomosed (IRA) pigs. For 3 weeks, four groups of six pigs were allocated to the treatments (CAS-INT, CAS-IRA, BL-INT, and BL-IRA). Diet-induced hypercholesterolemia was inhibited by the BL through a substantial decrease in plasma LDL-cholesterol. The BL also reduced liver esterified and total cholesterol, increased hepatic LDL receptor synthesis and HMG-CoA reductase activity, and stimulated intestinal bile acid reabsorption. The neutral sterol output was higher in BL- than in CAS-fed pigs. The bile acid output was lower in IRA than in INT pigs. Surgery also prevented steroid microbial transformation, but it did not influence plasma cholesterol levels. These results suggest that the hypocholesterolemic effect of the BL, compared with the CAS, is attributable to impaired intestinal cholesterol absorption, probably involving increased bile acid reabsorption and higher contents of dietary phytosterols, both factors that reduce the micellar solubilization of cholesterol. Furthermore, according to our data, the contribution of the large intestine to cholesterol metabolism is very weak.     

An SOS-regulated operon involved in damage-inducible mutagenesis in Caulobacter crescentus

DNA polymerases of the Y-family, such as Escherichia coli UmuC and DinB, are specialized enzymes induced by the SOS response, which bypass lesions allowing the continuation of DNA replication. umuDC orthologs are absent in Caulobacter crescentus and other bacteria, raising the question about the existence of SOS mutagenesis in these organisms. Here, we report that the C.crescentus dinB ortholog is not involved in damage-induced mutagenesis. However, an operon composed of two hypothetical genes and dnaE2, encoding a second copy of the catalytic subunit of Pol III, is damage inducible in a recA-dependent manner, and is responsible for most ultraviolet (UV) and mitomycin C-induced mutations in C.crescentus. The results demonstrate that the three genes are required for the error-prone processing of DNA lesions. The two hypothetical genes were named imuA and imuB, after inducible mutagenesis. ImuB is similar to proteins of the Y-family of polymerases, and possibly cooperates with DnaE2 in lesion bypass. The mutations arising as a consequence of the activity of the imuAB dnaE2 operon are rather unusual for UV irradiation, including G:C to C:G transversions.     

Effect of ovule position within the pod on the probability of seed production in Bauhinia ungulata (Fabaceae)

BACKGROUND AND AIMS: It has been claimed that ovules linearly ordered within a fruit differ in their probabilities of reaching maturity. This was investigated by studying the effect the position of an ovule within the pod has on seed abortion and seed production in Bauhinia ungulata. METHODS: Fruits collected during the dry seasons of 1999, 2000 and 2001 were opened, and the number, position and status of each ovule within the fruit were recorded. A GLM model was used to assess the effects of population, tree identity and ovule position within the pod on ovule fertilization, seed abortion, seed damage and seed maturation in two populations of B. ungulata. KEY RESULTS: Nearly 30% of the ovules were not fertilized in 1999; this percentage dropped to 5% the following two years. Seed abortion (50%) and seed damage (15%) were the same every year during the study period. Only 15% of the initial ovules developed into mature seeds in 1999; this value increased to 35% in 2000 and 2001. However, seed survivorship was dependent on the position of the ovule within the pod; non-fertilized and early aborted ovules were found more often near the basal end of the ovary. The frequency of seed damage was not affected by position. Mature seeds were found mainly in the stylar half of fruits, where ovules are likely to be fertilized by fast pollen tubes. CONCLUSIONS: The pattern of seed production in B. ungulata is non-random but is dependent upon the position of the ovule within the pod. The results suggest that the seeds produced within a fruit might differ in their vigour.     

Onychomycosis in Ceará (Northeast Brazil): epidemiological and laboratory aspects

Knowledge of epidemiological and mycological characteristics of onychomycosis has been noted by many authors as being an important tool for control of these fungal infections. This study seeks to improve knowledge of onychomycosis epidemiology and mycological features. Samples were taken from infected fingernails and toenails of 976 patients undergoing treatment at a respected Dermatology Center in Ceará, Fortaleza, CE, Brazil. Specimens from 512 patients (52%) were positive for onychomycosis. From the culture-positive samples, yeasts of the genus Candida (C. albicans, C. tropicalis, C. krusei, C. parapsilosis) were dominant. The dermatophytes isolated (Trichophyton rubrum, T. tonsurans, T. mentagrophytes var. mentagrophytes) were dominant in 46 patients (12.99%). The mould Fusarium spp. was isolated from 29 patients (8.19%). Yeast of the genus Candida is the main causal factor in onychomycosis in our region. Also, the study showed the importance of performing direct examination and culture in diagnosis of onychomycosis.     

Tendency for oxidation of annelid hemoglobin at alkaline pH and dissociated states probed by redox titration

The redox titration of extracellular hemoglobin of Glossoscolex paulistus (Annelidea) was investigated in different pH conditions and after dissociation induced by pressure. Oxidation increased with increasing pH, as shown by the reduced amount of ferricyanide necessary for the oxidation of hemoglobin. This behavior was the opposite of that of vertebrate hemoglobins. The potential of half oxidation (E_{1 / 2}) changed from − 65.3 to + 146.8 mV when the pH increased from 4.50 to 8.75. The functional properties indicated a reduction in the log P₅₀ from 1.28 to 0.28 in this pH range. The dissociation at alkaline pH or induced by high pressure, confirmed by HPLC gel filtration, suggested that disassembly of the hemoglobin could be involved in the increased potential for oxidation. These results suggest that the high stability and prolonged lifetime common to invertebrate hemoglobins is related to their low tendency to oxidize at acidic pH, in contrast to vertebrate hemoglobins.