Distribution and localization of immunoreactive FMRFamide-like peptides in the lancelet.

Immunofluorescence was used to study the distribution of FMRFamide (Phe-Met-Arg-Phe-NH2) in premetamorphic larvae and adults of the lancelet, Branchiostoma lanceolatum. In the larvae, FMR-Famide-containing presumably neuronal perikarya and fibers were limited to the anterior third of the dorsal nerve cord. Throughout this region, most of the immunoreactive perikarya and fibers were located ventrolaterally and ventrally within the nerve cord; in addition, in the caudal part of the cerebral vesicle, some of the immunofluorescent cells projected cytoplasmic extensions across the slot-like neural canal. In adult lancelets, immunofluorescence was detected in cells of the Hatschek's pit (a probable homologue of the anterior hypophysis of vertebrates); however, no immunofluorescence was detected in the larval preoral pit, which is the ontogenetic precursor of Hatschek's pit. Moreover, the FMR-Famide-containing elements do not show immunoreactivity to other peptides of the FaRPs family such as pancreatic polypeptide (PP). The results suggest that FMRF-amide may be involved in neuroendocrine functions of lancelets.     

High-performance liquid chromatographic determination of paclitaxel in rat serum: application to a toxicokinetic study

A simple and sensitive high-performance liquid chromatographic method is described for the determination of paclitaxel (Taxol^®) at 230 nm using a Nucleosil C₁₈ (5 μm) column and a methanol–water (70:30, v/v) mobile phase following a single-step extraction from serum with dichloromethane. The assay was validated against the classical criteria and was applied to a toxicokinetic study in rats after one or five, one per week) intraperitoneal administrations of 16 mg/kg Taxol^®.     

Development and Field Performance of a Broad-Spectrum Nonviable Asporogenic Recombinant Strain of Bacillus thuringiensis with Greater Potency and UV Resistance

The main problems with Bacillus thuringiensis products for pest control are their often narrow activity spectrum, high sensitivity to UV degradation, and low cost effectiveness (high potency required). We constructed a sporulation-deficient SigK⁻ B. thuringiensis strain that expressed a chimeric cry1C/Ab gene, the product of which had high activity against various lepidopteran pests, including Spodoptera littoralis (Egyptian cotton leaf worm) and Spodoptera exigua (lesser [beet] armyworm), which are not readily controlled by other Cry δ-endotoxins. The SigK⁻ host strain carried the cry1Ac gene, the product of which is highly active against the larvae of the major pests Ostrinia nubilalis (European corn borer) and Heliothis virescens (tobacco budworm). This new strain had greater potency and a broader activity spectrum than the parent strain. The crystals produced by the asporogenic strain remained encapsulated within the cells, which protected them from UV degradation. The cry1C/Ab gene was introduced into the B. thuringiensis host via a site-specific recombination vector so that unwanted DNA was eliminated. Therefore, the final construct contained no sequences of non-B. thuringiensis origin. As the recombinant strain is a mutant blocked at late sporulation, it does not produce viable spores and therefore cannot compete with wild-type B. thuringiensis strains in the environment. It is thus a very safe biopesticide. In field trials, this new recombinant strain protected cabbage and broccoli against a pest complex under natural infestation conditions.     

Effect of fertilization pulses on the production of <Emphasis Type="Italic">Gracilaria birdiae</Emphasis> seedlings under laboratory and field conditions

The genus Gracilaria is one of the most important sources of agar in the world. In Brazil, Gracilaria birdiae is the main commercially exploited species; however, overexploitation has contributed to the depletion of natural beds. In order to obtain more information so as to consolidate G. birdiae cultivation, studies under laboratory (indoor and outdoor) and field (sea and shrimp pond) conditions were conducted to evaluate the effects of fertilizer pulses on biomass and relative growth rate (RGR) of this species. The following nutrient sources used were (T₁) shrimp-pond effluent, (T₂) fertilizer for aquarium plants (Mbreda), and (T₃) fertilizer extract of Ascophyllum nodosum (Acadian). Significant differences for growth were recorded over time for all treatments in both outdoor and field conditions (p < 0.001). The highest RGRs were recorded for treatments that used pulses of commercial fertilizers (T₂ and T₃) and the lowest for treatment using shrimp-pond effluent pulses (T₁). The analysis of the nutrient content in tissue also showed a relationship between growth and nitrogen and phosphorus accumulation in the algal tissues. The N/P ratio indicated a significant effect on the growth of G. birdiae and the highest RGRs were registered for seedlings with a N/P ratio ≥16 (T₂ and T₃). In conclusion, the best results were recorded for the Mbreda and Acadian commercial fertilizers. However, although no significant differences were detected between growth and the two fertilizers (T₂ and T₃), the seedlings cultivated under Acadian pulses showed a better performance against environmental stress caused by reduced salinity.     

Production and purification of an untagged recombinant pneumococcal surface protein A (PspA4Pro) with high-purity and low endotoxin content

Applied Microbiology and Biotechnology - Streptococcus pneumoniae is the main cause of pneumonia, meningitis, and other conditions that kill thousands of children every year worldwide. The...     

Chemical Composition,Antibacterial, Antibiofilm and Synergistic Properties of Essential Oils from Eucalyptus globulus Labill. and Seven Mediterranean Aromatic Plants

Essential oils (EOs) from Eucalyptus globulus Labill . ssp. globulus and from Mediterranean autochthonous aromatic plants – Thymus mastichina L., Mentha pulegium L., Rosmarinus officinalis L., Calamintha nepeta (L.) Savi ssp. nepeta, Cistus ladanifer L., Foeniculum vulgare L., Dittrichia viscosa (L.) Greuter ssp. viscosa – were extracted by hydrodistillation and characterized by GC‐FID and NMR spectroscopy. EOs were evaluated for antimicrobial properties against several bacterial strains, using diverse methods, namely, the agar disc‐diffusion method, the microdilution method, the crystal violet assay and the Live/Dead staining for assessment of biofilm formation. Potential synergy was assessed by a checkerboard method. EOs of R. officinalis and C. ladanifer showed a predominance in monoterpene hydrocarbons (> 60%); EOs of C. nepeta, M. pulegium, T. mastichina, E. globulus and F. vulgare were rich in oxygenated monoterpenes (62 – 96%) whereas EO of D. viscosa was mainly composed of oxygenated sesquiterpenes (54%). All EOs showed antimicrobial activity; M. pulegium and E. globulus generally had the strongest antimicrobial activity. EO of C. nepeta was the most promising in hampering the biofilm formation. The combinations D. viscosa/C. nepeta and E. globulus/T. mastichina were synergistic against Staphylococcus aureus. These results support the notion that EOs from the aromatic plants herein reported should be further explored as potential pharmaceuticals and/or food preservatives.     

A combination of behavioral and physiological indicators for assessing pig welfare on the farm

The purpose of this research was to identify pig welfare indicators that could help in recognizing stressful practices on farm. The study evaluated behavioral and physiological indicators (cortisol and negative acute phase proteins) in 2 groups of 20 female pigs 4 months old after a 48-hr transport. The first group (A) was transported at the end of May, the second (B) in June. Behavioral observations and blood collection occurred at arrival (D1) and 28 days later (D28). Compared with within-animal control samples obtained 28 days later, pigs of Group A had increased cortisol levels and decreased albumin concentrations after arrival. As demonstrated by lesion and behavior observations, the effect on cortisol and albumin was higher in Group B pigs after a tail-biting episode occurred. The study has reported no evidence of Retinol Binding Protein (RBP) in pigs. A method developed for swine RBP quantification found RBP strongly reduced in D28 samples of Group B, confirming it to be a negative protein in pigs. The suggested combination of physiological and behavioral indicators could provide useful information on the welfare state of an animal.     

Auxin production and detection of the gene coding for the Auxin Efflux Carrier (AEC) protein in <Emphasis Type="Italic">Paenibacillus polymyxa</Emphasis>

Different species of Paenibacillus are considered to be plant growth-promoting rhizobacteria (PGPR) due to their ability to repress soil borne pathogens, fix atmospheric nitrogen, induce plant resistance to diseases and/or produce plant growth-regulating substances such as auxins. Although it is known that indole-3-acetic acid (IAA) is the primary naturally occurring auxin excreted by Paenibacillus species, its transport mechanisms (auxin efflux carriers) have not yet been characterized. In this study, the auxin production of P. polymyxa and P. graminis, which are prevalent in the rhizospheres of maize and sorghum sown in Brazil, was evaluated. In addition, the gene encoding the Auxin Efflux Carrier (AEC) protein from P. polymyxa DSM36(T) was sequenced and used to determine if various strains of P. polymyxa and P. graminis possessed this gene. Each of the 68 P. polymyxa strains evaluated in this study was able to produce IAA, which was produced at concentrations varying from 1 to 17 microg/ml. However, auxin production was not detected in any of the 13 P. graminis strains tested in this study. Different primers were designed for the PCR amplification of the gene coding for the AEC in P. polymyxa, and the predicted protein of 319 aa was homologous to AEC from Bacillus amyloliquefaciens, B. licheniformis, and B. subtilis. However, no product was observed when these primers were used to amplify the genomic DNA of seven strains of P. graminis, which suggests that this gene is not present in this species. Moreover, none of the P. graminis genomes tested were homologous to the gene coding for AEC, whereas all of the P. polymyxa genomes evaluated were. This is the first study to demonstrate that the AEC protein is present in P. polymyxa genome.     

Toxoplasma gondii: Evidence for the transmission by semen in dogs

Ten male dogs were distributed into three experimental groups for infection with Toxoplasma gondii: GI - three dogs inoculated with 2.0 × 10⁵ P strais oocysts, GII - three dogs infected with 1.0 × 10⁶ RH strain tachyzoites, and GIII - four controls dogs. Several clinical parameters were evaluated. IFAT was performed to detect anti-T. gondii antibodies. Presence of the parasite in semen was evaluated by PCR and bioassay techniques. Tissue parasitism was examined using bioassays and immunohistochemistry in testicle and epididymis fragments collected after orchiectomy. In semen samples collected from these two groups, the presence of T. gondii was verified by bioassays and PCR. T. gondii was detected by immunohistochemistry in tissues (testicle and epididymis fragments) of all six experimentally infected dogs. The T. gondii-positive seminal samples were used in the artificial insemination (AI) of four female dogs free of toxoplasmic infection. Seven days after AI, all of the female dogs presented serologic conversion (IFAT). Fetal reabsorption occurred in two of the dogs, while the others sustained full-term gestation. Several T. gondii cysts were detected in the brains of four offspring. These results suggest that T. gondii can be sexually transmitted in domestic dogs.     

Rep-PCR of tropical rhizobia for strain fingerprinting, biodiversity appraisal and as a taxonomic and phylogenetic tool

With more than 30 million doses of rhizobial inoculants marketed per year, it is probable that Brazilian agriculture benefits more than any other country from symbiotic N₂ fixation. As a result of strain-selection programs, 142 strains of rhizobia are officially recommended for use in commercial inoculants for ninety-six leguminous crops. In this study, sixty-eight of these elite strains were characterized by rep-PCR with the BOX-primer. Reproducibility of the DNA profiles was confirmed, suggesting efficacy of BOX-PCR both for control of quality of inoculants and for preliminary characterization of rhizobial culture collections. Strains of different species never showed similarity higher than 70% in the BOX-PCR analysis, however, some strains of the same species fit into more than one cluster, and correlation between BOX-PCR products and l6S rRNA sequences was low (7.6%). On the other hand, a polyphasic approach — 20%∶80% of BOX-PCR:16S rRNA which correlated well with the l6S rRNA analysis (95%), and provided higher definition of the genotypes, resulting in clearer indications of the taxonomic groups — might expedite rhizobial diversity studies.