RESUMO
Peat carbon accumulation is controlled by both large scale factors, such as climate and hydrological setting, and small scale factors, such as microtopography and plant community. These small scale factors commonly vary within peatlands and can cause variation in biogeochemical traits and carbon accumulation within the same site. To understand these within-site variations, we investigated long term carbon accumulation, peat decomposition, biogeochemistry of pore water and plant macrofossils along a transect in an ombrotrophic bog in southern Patagonia. An additional question we addressed is how historical deposition of volcanic ash on the peatland has affected its carbon balance. Variability in plant community and water table led to differences in long term peat and carbon accumulation (peat mossâ¯>â¯cushion plant), organic matter decomposition (cushion plantâ¯>â¯peat moss), and methane production (peat mossâ¯>â¯cushion plant). Macrofossil analysis and radiocarbon dating indicated a relationship between plant community and carbon accumulation or decomposition during the historical succession of vegetation in the peatland. C/N ratio and isotopic signatures reflected variability in plant community as litter source, and DOC concentrations were controlled by humification level. Volcanic ash deposition had only limited effect on plant composition, but it was associated with increased decomposition in overlying peat layers. This study highlights the importance of understanding how plant communities develop, as changes in communities could significantly affect the potential of ombrotrophic peatlands as C sink.
Assuntos
Biota/fisiologia , Carbono/metabolismo , Plantas/metabolismo , Áreas Alagadas , ArgentinaRESUMO
Eryngium foetidum L. is a biennial herb which is used extensively as a medicinal plant in most tropical regions. It is of increasing importance as a spice plant cultivated in India, Vietnam, Australia and elsewhere with well documented procedures for maximum yield. It also possesses a wide range of ethnomedicinal uses including treatment for burns, earache, fevers, hypertension, constipation, fits, asthma, stomach ache, worms, infertility complications, snake bites, diarrhea and malaria. Chemical evaluation of the leaves indicated the presence of flavonoids, tannins, a saponin and several triterpenoids; but no alkaloids were reported. A significant constituent of the essential oil of the plant is E-2-dodecenal ("eryngial"), with isomers of trimethylbenzaldehyde being present in lesser proportions. Variability in the composition of essential oil was clearly dependent on the geographic location of the growing plant. Pharmacological studies of the aerial plant parts have demonstrated anthelmintic activity due to eryngial, anti-inflammatory action due to the phytosterol fractions, anti-convulsant activity in the respective models, and selective antibacterial activity against Salmonella species and the Erwinia genus of bacteria. A fraction of the essential oil rich in eryngial is the subject of a US patent application for its effectiveness against parasitic trypanosomes, nematodes, fungi and bacteria in humans and other mammals. These findings suggest the need for further research of this herb and its products.
Assuntos
Eryngium/química , Etnofarmacologia , Óleos Voláteis/química , Fitoterapia , Extratos Vegetais/uso terapêutico , Animais , Humanos , Patentes como Assunto , Extratos Vegetais/química , Extratos Vegetais/farmacologiaRESUMO
Eleven Bacillus isolates from the surface and subsurface waters of the Gulf of Mexico were examined for their capacity to sporulate and harbor prophages. Occurrence of sporulation in each isolate was assessed through decoyinine induction, and putative lysogens were identified by prophage induction by mitomycin C treatment. No obvious correlation between ability to sporulate and prophage induction was found. Four strains that contained inducible virus-like particles (VLPs) were shown to sporulate. Four strains did not produce spores upon induction by decoyinine but contained inducible VLPs. Two of the strains did not produce virus-like particles or sporulate significantly upon induction. Isolate B14905 had a high level of virus-like particle production and a high occurrence of sporulation and was further examined by genomic sequencing in an attempt to shed light on the relationship between sporulation and lysogeny. In silico analysis of the B14905 genome revealed four prophage-like regions, one of which was independently sequenced from a mitomycin C-induced lysate. Based on PCR and transmission electron microscopy (TEM) analysis of an induced phage lysate, one is a noninducible phage remnant, one may be a defective phage-like bacteriocin, and two were inducible prophages. One of the inducible phages contained four putative transcriptional regulators, one of which was a SinR-like regulator that may be involved in the regulation of host sporulation. Isolates that both possess the capacity to sporulate and contain temperate phage may be well adapted for survival in the oligotrophic ocean.
Assuntos
Fagos Bacilares/genética , Bacillus/fisiologia , Lisogenia , Água do Mar/microbiologia , Bacillus/genética , Bacillus/virologia , Fagos Bacilares/efeitos dos fármacos , Fagos Bacilares/fisiologia , Bacillus anthracis/efeitos dos fármacos , Bacillus anthracis/genética , Sequência de Bases , DNA Viral/genética , Genoma Bacteriano , Genoma Viral , Integrases/genética , Lisogenia/efeitos dos fármacos , Microscopia Eletrônica de Transmissão , Mitomicina/farmacologia , Dados de Sequência Molecular , Oceanos e Mares , Prófagos/efeitos dos fármacos , Prófagos/genética , Prófagos/fisiologia , Esporos Bacterianos/efeitos dos fármacos , Esporos Bacterianos/genética , Proteínas Virais/genética , Ativação Viral/efeitos dos fármacos , Ativação Viral/genética , Ativação Viral/fisiologia , Integração Viral/efeitos dos fármacos , Replicação Viral/efeitos dos fármacos , Replicação Viral/genéticaRESUMO
Two new bis(monoterpenoid) indole alkaloid glucosides, bahienoside A (1) and bahienoside B (2), together with five known compounds, 5alpha-carboxystrictosidine, angustine, strictosamide, and (E)- and (Z)-vallesiachotamine, were isolated from the aerial parts of Psychotria bahiensis collected in Trinidad, West Indies. The structures of the compounds were elucidated using 1D and 2D NMR spectral methods, viz., (1)H, (13)C, (13)C DEPT, (1)H-(1)H COSY, HSQC, HMQC, HMBC, and TOCSY aided by IR, UV, and circular dichroism measurements.
Assuntos
Alcaloides Indólicos/isolamento & purificação , Monoterpenos/isolamento & purificação , Plantas Medicinais/química , Rubiaceae/química , Acetilação , Alcaloides Indólicos/química , Estrutura Molecular , Monoterpenos/química , Ressonância Magnética Nuclear Biomolecular , Estereoisomerismo , Trinidad e TobagoRESUMO
Bioassay-guided fractionation of the methanol extracts of the aerial parts of Psychotria uliginosa Sw yielded four known bioactive compounds: benz[g]isoquinoline-5,10-dione and 1-hydroxy-4,7-megastigmadien-3-one and blumenol A, which are chemically related to S-(+)-dehydrovomifoliol a known inhibitor of the germination of lettuce seeds. Evaluation of the basic components obtained from the methanol extract of the aerial parts of Psychotria bahiensis DC. yielded five bioactive indole monoterpenoid alkaloids which are known to display various levels of antiplasmodial and antitumor activity: 5 alpha-carboxystrictosidine, angustine, strictosamide and (E) and (Z)-vallesiachotamine; and the novel epimers bahienoside A and B which are currently being investigated for biological activity. The structures were determined by means of 1D and 2D NMR techniques
Assuntos
Extratos Vegetais , Plantas Medicinais , Trinidad e TobagoRESUMO
The phylogeny of 11 pigmented, aerobic, spore-forming isolates from marine sources was studied. Forty-two biochemical characteristics were examined, and a 16S rDNA sequence was obtained for each isolate. In a phylogenetic tree based on 16S sequencing, four isolates (NRRL B-14850, NRRL B-14904, NRRL B-14907, and NRRL B-14908) clustered with B. subtilis and related organisms; NRRL B-14907 was closely related to B. amyloliquefaciens. NRRL B-14907 and NRRL B-14908 were phenotypically similar to B. amyloliquefaciens and B. pumilus, respectively. Three strains (NRRL B-14906, NRRL B-14910, and NRRL B-14911) clustered in a clade that included B. firmus, B. lentus, and B. megaterium. NRRL B-14910 was closely related phenotypically and phylogenetically to B. megaterium. NRRL B-14905 clustered with the mesophilic round spore-producing species, B. fusiformis and B. sphaericus; the isolate was more closely related to B. fusiformis. NRRL B-14905 displayed characteristics typical of the B. sphaericus-like organisms. NRRL B-14909 and NRRL B-14912 clustered with the Paenibacillus species and displayed characteristics typical of the genus. Only NRRL B-14851, an unusually thin rod that forms very small spores, may represent a new Bacillus species.
Assuntos
Bacillus/classificação , Água do Mar/microbiologia , Microbiologia da Água , Bacillus/genética , Bacillus/metabolismo , DNA Bacteriano/análise , DNA Ribossômico/análise , México , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Filogenia , RNA Ribossômico 16S/análise , RNA Ribossômico 16S/genéticaRESUMO
Bioassay-guided fractionation of the methanol extracts of the aerial parts of Psychotria uliginosa Sw yielded four known bioactive compounds: benz[g]isoquinoline-5,10-dione and 1-hydroxy-4,7-megastigmadien-3-one and blumenol A, which are chemically related to S-(+)-dehydrovomifoliol a known inhibitor of the germination of lettuce seeds. Evaluation of the basic components obtained from the methanol extract of the aerial parts of Psychotria bahiensis DC. yielded five bioactive indole monoterpenoid alkaloids which are known to display various levels of antiplasmodial and antitumor activity: 5 alpha-carboxystrictosidine, angustine, strictosamide and (E) and (Z)-vallesiachotamine; and the novel epimers bahienoside A and B which are currently being investigated for biological activity. The structures were determined by means of 1D and 2D NMR techniques (AU)