Dihydrochalcones, coumarins and alkaloids from Metrodorea nigra

Two novel dihydrochalcones, 2′,3,4′,6′-tetrahydroxy-4-methoxy-3′,5-di-(3,3-dimethylallyl)-dihydrochalcone and 2′,.3,6′-trihydroxy-4-methoxy-5-(3,3-dimethylallyl)-3′,4′-(2″,2″-dimethyldihydropyran)-dihydrochalcone, have been isolated from fresh fruits of Metrodorea nigra. Stems and leaves showed a similar composition and we have isolated common steroids, simple coumarins, several furocoumarins, furoquinoline alkaloids and a furofuran lignan. From stems, we have also isolated the pentacyclic 6-C-monoterpenyl-5,7-dioxycoumarin, deoxybruceol. Structures of the isolated compounds were elucidated on the basis of spectral data.     

Internally quenched fluorogenic protease substrates: Solid-phase synthesis and fluorescence spectroscopy of peptides containing ortho-aminobenzoyl/dinitrophenyl groups as donor-acceptor pairs

Summary A general procedure, using the commonly employed solid-phase peptide synthesis methodology for obtaining internally quenched fluorogenic peptides with ortho-aminobenzoyl/dinitrophenyl groups as donor-acceptor pairs, is presented. The essential feature of this procedure is the synthesis of an N -Boc or-Fmoc derivative of glutamic acid with the -carboxyl group bound to N-(2,4-dinitrophenyl)-ethylenediamine (EDDnp), which provides the quencher moiety attached to the C-terminus of the substrate. The fluorescent donor group, ortho-aminobenzoic acid (Abz), is incorporated into the resin-bound peptide in the last coupling cycle. Depending on the resin type used, Abz-peptidyl-Gln-EDDnp or Abz-peptidyl-Glu-EDDnp is obtained. Using the procedure described above, substrates for human renin and tissue kallikreins were synthesised. Spectrofluorimetric measurements of Abz bound to the -amino group of proline showed that strong quenching of Abz fluorescence occurs in the absence of any acceptor group.     

Epilithic diatom community response to years of P04 fertilization: Kuparuk River,Alaska (68 N Lat.)

An arctic river was fertilized continuously through the ice-free season with phosphoric acid beginning in 1983. The epilithic diatom community increased in biomass in the first two years in response to the added limiting nutrient (Peterson et al., 1983). The diatom community switched from one dominated by Hannea arcus to one dominated by species of Achnanthes and Cymbella. The immediate responses to the P-addition were decreases in both the Shannon diversity and evenness indices. By the second year, the community diversity increased downriver reaching maximal species richness (110–127 spp). In 1985–1987, the epilithic algal biomass decreased an order of magnitude with both whole-river PO₄ (1985, 1987) and PO₄ + NH₄ addition (1986). In the 5th summer of fertilization, the reduction in biomass was clearly caused by a numerical increase of grazing, refugia-building chironomids (Orthocladiinae, primarily) (Gibeau, 1991; Gibeau, Miller, Hershey, in prep.). We assume the algal biomass reduction in the 3rd and 4th years was similarly caused by grazers with a two year time lag in the numerical response of these monovoltine species. The evenness of the community increased in 1986 as if it might have been grazed; however the number of immigrants was reduced. The community became dominated by Eunotia, Cymbella and Achnanthes, species either fast growing or more prostrate, as the erect species of Hannea Diatoma, and Fragillaria declined. A detrended correspondence analysis of the temporal and spatial diatom samples in species space (186 spp.) showed that the largest variation in the community was between years and less variation was associated with river fertilization. Samples from bioassay tubes run by Peterson et al. (1983) in the Kuparuk River showed P and N + P limitation as found in the river in 1983–84. Like the river samples, the largest change in the diatom community occurred between 15 and 25 day samples, more than that induced by fertilization. Diatoms sampled from all treatments taken at day 25 were more similar to one another than those sampled at day 15. Diatoms colonizing glass slides used in the bioassay tubes were dominated by Achnanthes linearis and Cymbella minuta. Of the 84 species found in bioassays, 26 species were present in all river samples for 4 years. Differences in the communities discriminated by multivariate methods were cause by changes in rare species and abundance patterns of common species.     

Spondyloepiphyseal dysplasia, chondroitin sulfate type: a possible defect of PAPS--chondroitin sulfate sulfotransferase in humans

Four patients with an unusual form of spondyloepiphyseal dysplasia excreted in the urine undersulfated chondroitin 6-sulfate (Biochem. Med. $\text{7}$, 415–423, 1973). The sera of these patients show a low activity of PAPS — chondroitin sulfate sulfotransferase, while the undersulfated chondroitin sulfate present in their urine is a much better acceptor of ${}^{35}\text{SO}{}_4$ than standard chondroitin sulfate when they are incubated with [${}^{35}\text{S}$]PAPS and normal sulfotransferases. These results suggest that in these patients the skeletal lesions are secondary to a defect in the synthesis of chondroitin sulfate involving specifically the sulfotransferase activity.     

Cryptogenic hepatitis patients have a higher Bartonella sp.-DNA detection in blood and skin samples than patients with non-viral hepatitis of known cause

BackgroundThis study aimed to assess the prevalence of Bartonella sp.-DNA detection in blood and skin samples from patients with non-viral end-stage liver disease awaiting liver transplantation.Methodology/Principal findingsBlood samples and healthy skin fragments from 50 patients were tested using microbiological and molecular methods. Fifteen patients had cryptogenic hepatitis (CH) and 35 had alcoholic, drug-induced or autoimmune liver disease. DNA was extracted from whole blood and liquid culture samples, isolates, and skin fragments. Thirteen of the 50 patients (26%) had Bartonella henselae DNA detection in their blood (9/50) and/or skin (5/50) samples. Colonies were isolated in 3/50 (6%) and infection was detected in 7/50 (14%) of the 50 patients. B. henselae-DNA detection was more prevalent in patients with CH than in other patients (p = 0.040). Of 39 patients followed-up for at least two years, a higher mortality rate was observed among patients with CH infected with B. henselae (p = 0.039).Conclusions/SignificanceFurther studies assessing the role of B. henselae infection in the pathogenesis of hepatitis patients must be urgently conducted.     

Effect of High-Intensity Interval Training on Cardiac Apoptosis Markers in Methamphetamine-Dependent Rats

Chronic methamphetamine use increases apoptosis, leading to heart failure and sudden cardiac death. Previous studies have shown the importance of high-intensity interval training (HIIT) in reducing indices of cardiac tissue apoptosis in different patients, but in the field of sports science, the molecular mechanisms of apoptosis in methamphetamine-dependent rats are still unclear. The present article aimed to investigate the changes in cardiac apoptosis markers in methamphetamine-dependent rats in response to HIIT. Left ventricular tissue was used to evaluate caspase-3, melusin, FAK, and IQGAP1 gene expression. Rats were divided into four groups: sham, methamphetamine (METH), METH-control, and METH-HIIT. METH was injected for 21 days and then the METH-HIIT group performed HIIT for 8 weeks at 5 sessions per week. The METH groups showed increased caspase-3 gene expression and decreased melusin, FAK, and IQGAP1 when compared to the sham group. METH-HIIT showed decreased caspase-3 and increased melusin and FAK gene expression compared with the METH and METH-control groups. The IQGAP1 gene was higher in METH-HIIT when compared with METH, while no difference was observed between METH-HIIT and METH-control. Twenty-one days of METH exposure increased apoptosis markers in rat cardiac tissue; however, HIIT might have a protective effect, as shown by the apoptosis markers.     

Leishmania braziliensis causing human disease in Northeast Brazil presents loci with genotypes in long-term equilibrium

BackgroundLeishmaniases are neglected tropical diseases that inflict great burden to poor areas of the globe. Intense research has aimed to identify parasite genetic signatures predictive of infection outcomes. Consistency of diagnostic tools based on these markers would greatly benefit from accurate understanding of Leishmania spp. population genetics. We explored two chromosomal loci to characterize a population of L. braziliensis causing human disease in Northeast Brazil.Methodology/Principal findingsTwo temporally distinct samples of L. braziliensis were obtained from patients attending the leishmaniasis clinic at the village of Corte de Pedra: (2008–2011) primary sample, N = 120; (1999–2001) validation sample, N = 35. Parasites were genotyped by Sanger’s sequencing of two 600 base pairs loci starting at nucleotide positions 3,074 and 425,451 of chromosomes 24 and 28, respectively. Genotypes based on haplotypes of biallelic positions in each locus were tested for several population genetic parameters as well as for geographic clustering within the region. Ample geographic overlap of genotypes at the two loci was observed as indicated by non-significant Cusick and Edward’s comparisons. No linkage disequilibrium was detected among combinations of haplotypes for both parasite samples. Homozygous and heterozygous genotypes displayed Hardy-Weinberg equilibrium (HWE) at both loci in the two samples when straight observed and expected counts were compared by Chi-square (p>0.5). However, Bayesian statistics using one million Monte-Carlo randomizations disclosed a less robust HWE for chromosome 24 genotypes, particularly in the primary sample (p = 0.04). Fixation indices (Fst) were consistently lower than 0.05 among individuals of the two samples at both tested loci, and no intra-populational structuralization could be detected using STRUCTURE software.Conclusions/SignificanceThese findings suggest that L. braziliensis can maintain stable populations in foci of human leishmaniasis and are capable of robust genetic recombination possibly due to events of sexual reproduction during the parasite’s lifecycle.     

Biological nitrogen fixation and phosphate solubilization by bacteria isolated from tropical soils

Introduction

In addition to fixing atmospheric nitrogen, some bacterial isolates can also solubilize insoluble phosphates, further contributing to plant growth.

Aims

The objectives of this study were the following: isolate, select, and identify nodulating bacteria in the cowpea that are efficient not only in biological nitrogen fixation (BNF) but also in the solubilization of insoluble inorganic phosphates; identify and quantify the organic acids produced; and establish the relationship between those acids and the solubilizing capacity.

Methods

The bacteria were captured from two soils containing high concentrations of insoluble phosphorus from the cities of Lavras and Patos de Minas, using the cowpea [Vigna unguiculata (L.) Walp.] as bait. We obtained 78 strains, which were characterized according to their cultural attributes in culture medium 79 with the strains UFLA 03-84, INPA 03-11B, and BR3267 (approved by the Ministry of Livestock and Supply Agriculture—MAPA, as inoculants for the cowpea) and Burkholderia cepacia (LMG1222^T), which was used as a positive control for phosphate solubilization. Strains that were selected for their efficiency in both processes were identified by 16S rDNA sequence analysis. We evaluated the symbiotic efficiency (BNF) in a greenhouse and the solubilization efficiency of CaHPO₄, Al(H₂PO₄)₃, and FePO₄.2H₂O in solid and liquid GELP media. Strains that excelled at the solubilization of these phosphate sources were also evaluated for the production of the following organic acids: oxalic, citric, gluconic, lactic, succinic, and propionic.

Results

The presence of Acinetobacter, Bacillus, Firmicutes, Microbacterium, Paenibacillus, and Rhizobium was detected by 16S rDNA sequencing and analysis. Bacterial strains obtained from cowpea nodules varied greatly in the efficiency of their BNF and phosphate solubilization processes, especially in the strains UFLA 03-09, UFLA 03-10, UFLA 03-12, and UFLA 03-13, which were more efficient in both processes. More strains were able to solubilize insoluble inorganic calcium and iron phosphates in liquid medium than in solid medium. The production of organic acids was related to the solubilization of CaHPO₄ and FePO₄.2H₂O for some strains, and the type and concentration of the acid influenced this process.

Conclusions

These are the first results obtained with bacterial isolates from tropical soils in which the production of organic acids was detected and quantified to examine the solubilization of insoluble inorganic phosphates.     

Biotic integrity of the arthropod communities in the natural forests of Azores

The loss of biotic integrity in ecosystems due to human pressure has been receiving much attention from the scientific community. The primary aim of this study is to understand how the increasing human pressure on natural forests in the Azorean archipelago (North Atlantic) is affecting their epigean arthropod communities and which biological parameters it affects most. An expert team did fieldwork covering most of the natural forests (mainly inside nature reserves) of the archipelago using standardized pitfall trapping. To build a multimetric index we tested a number of taxonomic and ecological parameters that can potentially be influenced by disturbance. Sixteen of these were found to be significantly influenced by disturbance in forests. We retained seven metrics due to both, desirable scalability properties and relatively low correlation between them. These included the percentages of endemic and predator species richness and also predator abundance, which are inversely related to disturbance; and the percentages of native and saprophagous species richness and introduced and herbivore abundance, which are positively related to disturbance. All seven metrics were combined in an Index of Biotic Integrity (IBI) value. We then proceeded to understand which potential disturbance factors are influencing the biotic integrity of communities and how such influence is felt. Five disturbance factors were found to influence the IBI, although in different ways: the size and fragmentation of reserves, the distance of sites to the reserve borders, the invasion by alien plants and the density of human paths at the sites. Given that only percentages of taxonomical or ecological characteristics were chosen as metrics, we tested and found the scalability of the IBI to be possible, allowing the comparison of sites with different collecting effort or even the comparison of reserves with different areas and numbers of collecting sites in each. Finally, we propose a novel graphical representation for multimetric indices like the IBI, one which allows retaining much of the information that is usually lost in multimetric indices.