Integrated versus stand-alone second generation ethanol production from sugarcane bagasse and trash

Ethanol production from lignocellulosic materials is often conceived considering independent, stand-alone production plants; in the Brazilian scenario, where part of the potential feedstock (sugarcane bagasse) for second generation ethanol production is already available at conventional first generation production plants, an integrated first and second generation production process seems to be the most obvious option. In this study stand-alone second generation ethanol production from surplus sugarcane bagasse and trash is compared with conventional first generation ethanol production from sugarcane and with integrated first and second generation; simulations were developed to represent the different technological scenarios, which provided data for economic and environmental analysis. Results show that the integrated first and second generation ethanol production process from sugarcane leads to better economic results when compared with the stand-alone plant, especially when advanced hydrolysis technologies and pentoses fermentation are included.     

Metabolism of semisynthetic single-chain GM1 derivatives in cerebellar granule cells in culture

Semisynthetic single-chain GM1 derivatives containing N-acetyl-sphingosine (LIGA4) or N-dichloroacetyl-sphingosine (LIGA20) were recently reported to exert strong protection against glutamate-induced neuronal death in primary cultures of cerebellar granule cells. Elucidation of the molecular mechanism underlying the evoked effect requires knowledge of the metabolic fate of such molecules in the same cultured cells. For this, LIGA4 and LIGA20 were made radioactive on the long chain base moiety and added to cerebellar granule cells in culture in parallel with GM1 ganglioside. The metabolic fate was then investigated. It was found that both these molecules were easily taken up by the cells and promptly metabolized in a fashion qualitatively similar to that of control GM1. The highest amount processed was attributed to the different aggregation properties of LIGAs in solution. Among metabolites, higher accumulation of the single-chain ceramide residues was found after LIGA administration. Interestingly, sphingomyelin was generated, regardless the added compound, suggesting a recycling of the free long chain base.     

Antimicrobial and Cytotoxic Activity of Extracts of Ferula heuffelii Griseb. ex Heuff. and Its Metabolites

The antimicrobial and cytotoxic activities of isolates (CHCl₃ and MeOH extracts and selected metabolites) obtained from the underground parts of the Balkan endemic plant Ferula heuffelii Griseb . ex Heuff . were assessed. The CHCl₃ and MeOH extracts exhibited moderate antimicrobial activity, being more pronounced against Gram‐positive than Gram‐negative bacteria, especially against Staphylococcus aureus (MIC=12.5 μg/ml for both extracts) and Micrococcus luteus (MIC=50 and 12.5 μg/ml, resp.). Among the tested metabolites, (6E)‐1‐(2,4‐dihydroxyphenyl)‐3,7,11‐trimethyl‐3‐vinyldodeca‐6,10‐dien‐1‐one ( 2 ) and (2S*,3R*)‐2‐[(3E)‐4,8‐dimethylnona‐3,7‐dien‐1‐yl]‐2,3‐dihydro‐7‐hydroxy‐2,3‐dimethylfuro[3,2‐c]coumarin ( 4 ) demonstrated the best antimicrobial activity. Compounds 2 and 4 both strongly inhibited the growth of M. luteus (MIC=11.2 and 5.2 μM , resp.) and Staphylococcus epidermidis (MIC=22.5 and 10.5 μM , resp.) and compound 2 additionally also the growth of Bacillus subtilis (MIC=11.2 μM ). The cytotoxic activity of the isolates was tested against three human cancer cell lines, viz., cervical adenocarcinoma (HeLa), chronic myelogenous leukemia (K562), and breast cancer (MCF‐7) cells. The CHCl₃ extract exhibited strong cytotoxic activity against all cell lines (IC₅₀<11.0 μg/ml). All compounds strongly inhibited the growth of the K562 and HeLa cell lines. Compound 4 exhibited also a strong activity against the MCF‐7 cell line, comparable to that of cisplatin (IC₅₀=22.32±1.32 vs. 18.67±0.75μM ).     

Urinary proteomics for the study of genetic kidney diseases

Despite their low prevalence, genetic kidney diseases (GKD) still represent a serious health problem. They often lead to kidney failure and to the consequent need of dialysis or kidney transplant. To date, reliable diagnosis requires laborious genetic tests and/or a renal biopsy. Moreover, only scant and non-specific markers exist for prognostic purposes. Biomarkers assayed in an easily available and low-cost sample, such as urine, would be highly valuable. Urinary proteomics can provide clues related to their development through the identification of differentially expressed proteins codified by the affected genes, or other dis-regulated species, in total or fractionated urine, providing novel mechanistic insights. In this review, the authors summarize and discuss the results of the main proteomic investigations on GKD urine samples and in urinary extracellular vesicles.     

The Helicobacter pylori VacA cytotoxin activates RBL-2H3 cells by inducing cytosolic calcium oscillations

Helicobacter pylori causes an acute inflammatory response followed by chronic infection of the human gastric mucosa. Identification of the bacterial molecules endowed with a pro-inflammatory activity is essential to a molecular understanding of the pathogenesis of H. pylori associated diseases. The vacuolating cytotoxin A (VacA) induces mast cells to release pro-inflammatory cytokines. Here, we show that VacA activates the mast cell line RBL-2H3 by rapidly inducing an oscillation of the level of cytosolic calcium with exocytosis of secretory granules. Cytosolic calcium derives mainly from intracellular stores. VacA also stimulates a calcium-dependent production of pro-inflammatory cytokines, including tumour necrosis factor alpha (TNF-alpha). These observations indicate that VacA may act as a pro-inflammatory factor of H. pylori at very early stages of the innate immune response.     

Proposal to create subspecies of <Emphasis Type="Italic">Rickettsia conorii</Emphasis> based on multi-locus sequence typing and an emended description of <Emphasis Type="Italic">Rickettsia conorii</Emphasis>

Background  

Rickettsiae closely related to the Malish strain, the reference Rickettsia conorii strain, include Indian tick typhus rickettsia (ITTR), Israeli spotted fever rickettsia (ISFR), and Astrakhan fever rickettsia (AFR). Although closely related genotypically, they are distinct serotypically. Using multilocus sequence typing (MLST), we have recently found that distinct serotypes may not always represent distinct species within the Rickettsia genus. We investigated the possibility of classifying rickettsiae closely related to R. conorii as R. conorii subspecies as proposed by the ad hoc committee on reconciliation of approaches to bacterial systematics. For this, we first estimated their genotypic variability by using MLST including the sequencing of 5 genes, of 31 rickettsial isolates closely related to R. conorii strain Malish, 1 ITTR isolate, 2 isolates and 3 tick amplicons of AFR, and 2 ISFR isolates. Then, we selected a representative of each MLST genotype and used multi-spacer typing (MST) and mouse serotyping to estimate their degree of taxonomic relatedness.     

Kinetics of the interactions between yeast elongation factors 1A and 1Balpha, guanine nucleotides, and aminoacyl-tRNA

The interactions of elongation factor 1A (eEF1A) from Saccharomyces cerevisiae with elongation factor 1Balpha (eEF1Balpha), guanine nucleotides, and aminoacyl-tRNA were studied kinetically by fluorescence stopped-flow. eEF1A has similar affinities for GDP and GTP, 0.4 and 1.1 microm, respectively. Dissociation of nucleotides from eEF1A in the absence of the guanine nucleotide exchange factor is slow (about 0.1 s(-1)) and is accelerated by eEF1Balpha by 320-fold and 250-fold for GDP and GTP, respectively. The rate constant of eEF1Balpha binding to eEF1A (10(7)-10(8) M (-1) s(-1)) is independent of guanine nucleotides. At the concentrations of nucleotides and factors prevailing in the cell, the overall exchange rate is expected to be in the range of 6 s(-1), which is compatible with the rate of protein synthesis in the cell. eEF1A.GTP binds Phe-tRNA(Phe) with a K(d) of 3 nm, whereas eEF1A.GDP shows no significant binding, indicating that eEF1A has similar tRNA binding properties as its prokaryotic homolog, EF-Tu.