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.     

Supernumerary chromosome system,C-banding pattern characterization and multiple nucleolus organizer regions in Moenkhausia sanctaefilomenae (Pisces,Characidae)

Chromosomes of Moenkhausia sanctaefilomenae (10 males and 20 females) collected from a tributary of the Tietê River (Botucatu, S.P. Brazil) were examined using kidney and testicular cells. Both males and females presented 2n=50 chromosomes and 1 to 8 small supernumerary microchromosomes. C-banding demonstrated positively stained heterochromatic blocks in almost every chromosome and a pattern of interstitial bands located in the same position in relation to the centromere on the long arm of a large number of chromosomes. Two large NORs were detected in pair 19 of all the silver-stained metaphases; zero to 6 additional small NORs were detected in other chromosomes. A general survey of the occurrence of supernumerary chromosomes in fishes is presented.     

Residual beta-cell function in type II diabetes and evaluation of the hepatic insulin extraction

Insulin and C-peptide (free insulin and C-peptide in insulin-treated patients) were measured after glucose stimulation in nine Type II diabetics on chlorpropamide, eleven insulin-treated maturity-onset diabetics and in 8 normal controls. Dissociation between C-peptide and insulin response to glucose was observed in several diabetics. The relation between incremental molar areas under C-peptide and insulin curves, after glucose challenge (delta CPR - delta IRI/delta CPR) were used to evaluate the hepatic insulin extraction in all but the insulin-treated diabetics. The lower insulin requirements and better control of the short-duration insulin-treated maturity-onset diabetics in relation to the long-term ones could not be explained either by the residual insulin secretion or by the level of "insulin antibodies". The chlorpropamide-responsive patients presented higher insulin levels after the glucose challenge and a lower hepatic insulin extraction than the non-responsive ones.     

Effect of immune system imagery on secretory IgA

This study was an investigation of the effects of physiologically-oriented mental imagery on immune functioning. College students with normal medical histories were randomly selected to one of three groups. Subjects in Group 1 participated in short educational training on the production of secretory immunoglobulin A. They were then tested on salivary IgA, skin temperature, and the Profile of Mood States (POMS) before and after listening to a 17-minute tape of imagery instructions with specially composed background entrainment music designed to enhance imagery. Subjects in Group 2 (placebo controls) listened to the same music but received nor formal training on the immune system. Group 3 acted as a control and subjects were tested before and after 17 minutes of no activity. Treatment groups listened to their tapes at home on a bi-daily basis for six weeks All groups were again tested at Weeks 3 and 6. Secretory IgA was analyzed using standard radial immunodiffusion techniques. Repeated measures analyses of variance with planned orthogonal contrasts were used to evaluate the data. Significant overall increases (p<0.05) were found between pre- and posttests for all three trials. Groups 1 and 2 combined (treatment groups) yielded significantly greater increases in sIgA over Group 3 (control) for all three trials. Group 1 (imagery) was significantly higher than Group 2 (music) in antibody production for Trials 2 and 3. Symptomatology, recorded by subjects at Weeks 3 and 6, was significantly lower for three symptoms (rapid heartbeat, breathing difficulty, and jaw clenching), favoring both treatment groups over the control group.     

In planta transformation of Arabidopsis thaliana

Transformants of Arabidopsis thaliana can be generated without using tissue culture techniques by cutting primary and secondary inflorescence shoots at their bases and inoculating the wound sites with Agrobacterium tumefaciens suspensions. After three successive inoculations, treated plants are grown to maturity, harvested and the progeny screened for transformants on a selective medium. We have investigated the reproducibility and the overall efficiency of this simple in planta transformation procedure. In addition, we determined the T-DNA copy number and inheritance in the transformants and examined whether transformed progeny recovered from the same Agrobacterium-treated plant represent one or several independent transformation events. Our results indicate that in planta transformation is very reproducible and yields stably transformed seeds in 7–8 weeks. Since it does not employ tissue culture, the in planta procedure may be particularly valuable for transformation of A. thaliana ecotypes and mutants recalcitrant to in vitro regeneration. The transformation frequency was variable and was not affected by lower growth temperature, shorter photoperiod or transformation vector. The majority of treated plants gave rise to only one transformant, but up to nine siblings were obtained from a single parental plant. Molecular analysis suggested that some of the siblings originated from a single transformed cell, while others were descended from multiple, independently transformed germ-line cells. More than 90% of the transformed progeny exhibited Mendelian segregation patterns of NPTII and GUS reporter genes. Of those, 60% contained one functional insert, 16% had two T-DNA inserts and 15% segregated for T-DNA inserts at more than two unlinked loci. The remaining transformants displayed non-Mendelian segregation ratios with a very high proportion of sensitive plants among the progeny. The small numbers of transformants recovered from individual T₁ plants and the fact that none of the T₂ progeny were homozygous for a specific T-DNA insert suggest that transformation occurs late in floral development.     

Immune Evasion by Helicobacter pylori: Gastric Spiral Bacteria Lack Surface Immunoglobulin Deposition and Reactivity with Homologous Antibodies

Background. Helicobacter pylori infection persists in the presence of potent serum and gastric mucosal anti-body responses against bacterial antigens. The aim of this article is to report on a study determine whether there is antibody deposition on H. pylori in vivo in the stomach of infected patients and whether gastric and cultured forms of H. pylori differ in their antibody reactivity.
Materials and Methods. Serum, gastric biopsies, and antral brushings were obtained from 10 patients having endoscopy. H. pylori was cultured from gastric biopsies. Bacterial samples were stained directly for immunoglobulin deposition and indirectly using rabbit antiurease serum or patient serum. Samples were examined by immunofluorescence microscopy and flow cytometry.
Results. Although spiral bacteria could be identified easily by acridine orange staining and antiurease staining of gastric brushings from H. pylori infected patients, gastric bacteria did not have detectable IgG or IgA present, and only one of five samples could be stained for IgG and IgA indirectly using patient serum. In contrast, cultured bacteria could be stained readily with homologous serum for IgG and IgA in the majority of cases. Low pH inhibited immunoglobulin reactivity with cultured H. pylori.
Conclusions. Gastric H. pylori may evade humoral defense owing to poor deposition of immunoglobulin in the gastric environment or failure to express surface antigens that are present on cultured forms of H. pylori.     

Mixed Infection with cagA-Positive and cagA-Negative Strains of Helicobacter pylori

Background Helicobacter pylori infection has been implicated strongly in the pathogenesis of gastritis, peptic ulcer disease, gastric adenocarcinoma, and gastric lymphoma, but the reasons for these widely different clinical outcomes are unknown. The aim of this study was to determine whether these differences could be due in part to mixed infection in the same individual, with bacteria having differences in pathogenic factors associated with ulcers.
Materials and Methods. The cagA gene of H. pylori was used to test for mixed infection because it is present in only some strains, and its presence has been associated with ulcers. Polymerase chain reaction (PCR) assays for the cagA gene were applied to H. pylori culture isolates and endoscopic gastric aspirates. Individual bacterial clones were tested for genetic similarity by random primer amplification and restriction endonuclease digestion of urease gene PCR products.
Results. The majority of H. pylori -positive patients had strongly cagA -positive culture isolates and endoscopic samples (62.5% and 69.6%, respectively). However, many of these patients had evidence of mixed infection with cagA negative and cagA positive strais in cultures isolates and endoscopic samples (25% and 17.4%, respectively). Mixed infection was found to be due to genetically unrelated strains in two patients in whom genetic analysis was performed.
Conclusion. Mixed infection with differences in substrain pathogenic factors might occur in H. pylori infection and might contribute to differences in clinical outcome.     

Preliminary investigation of feeding performance of larvae of early red-spotted grouper, Epinephelus coioides, reared with mixed zooplankton

Larvae of red-spotted grouper, Epinephelus coioides, were reared inoutdoor tanks with nauplii of copepods (mainly Pseudodiaptomus annandaleiand Acartia tsuensis) and/or rotifers, Brachionus rotundiformis. Grouperlarvae successfully started feeding on early stage nauplii even though theirabundance was as low as approximately 100 individuals l^–1 andshowed better survival and growth thereafter compared to those fed withrotifers only. Incidence of feeding reached 100% on day 4 whennauplii were available and only on day 9 when rotifers were given alone.Larvae seemed to be poor feeders at the onset of feeding, attempting tocapture any food organisms in the tank water. Selective feeding ability oflarvae started from day 4 and the larvae then preferred to feed on medium-and large-size nauplii rather than on rotifers as they grew. Larvae appearedto have a better chance at surviving in the presence of early stage nauplii,which were probably caught more easily than rotifers.     

Inhibition of cyclopropane fatty acid synthase by sinefungin and A9145C

Sinefungin and A9145C, antifungal antibiotic analogs of S-adeno-sylmethionine isolated from $\text{Streptomyces}\text{,}\text{griseolus}$, have been found to be very effective $\text{in}\text{,}\text{vitro}$ inhibitors of cyclopropane fatty acid synthase from $\text{Lactobacillus}\text{,}\text{plantarum}$. Both compounds exhibit linear competitive inhibition with a K_i for Sinefungin of 220 nM and a K_i for A9145C of 11 nM.