Production of fuel ethanol from cassava

Summary Ethanol production from fresh cassava roots using a low-temperature process was evaluated on a pilot-plant scale. The application of low-temperature cooking to cassava starch followed by a dual enzyme action resulted in an ethanol yield comparable to that of a traditional high-temperature cooking process. Pressurized distillation gave a satisfactory recovery efficiency of ethanol but was slightly lower than that obtained from atmospheric pressure distillation. Over 40% of the normal steam consumption was saved by adopting the low-temperature cooking and pressurized distillation systems in the cassava-to-ethanol process. The yield of anhydrous ethanol varied with the starch content in fresh cassava roots and was in the range of 185 to 200 liters per tonne.

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Resumen La producción de etanol a partir de raices frescas de cassava como materia prima, empleando un procedimiento a baja temperatura, ha sido evaluada a la escala de planta piloto. El empleo de baja temperatura en el tratamiento del almidón de cassava, sequido de una doble acción enzimática ha resultado en un rendimiento de etanol comparable al obtenido con el procedimiento tradicional de elevada temperatura. La destilación bajo presión ha presentado un rendimiento de etanol satisfactorio, aunque ligeramente inferior al obtenido en la destilación a la presión atmosférica. Se ahorro más de un 40% de consumo de energía en forma de vapor de agua al adoptar el tratamiento del almidón a baja temperatura y el proceso de destilación bajo presión en la producción de etanol a partir de cassava. El rendimiento de etanol anhidro varió según el contenido de almidón de la materia prima, oscilando entre 185 a 200 litros pot tonelada de cassava.

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Résumé La production d'éthanol à partir de racines fraîches de cassava comme matière première, à basse température, a été évaluée à l'échelle de plante d'essai. L'utilisation de température basse pour le traitement de l'amidon de cassava, suivi d'une double action enzymatique, a résulté en un rendement d'éthanol comparable a celui obtenu par le procédé traditionel a température élevée.: La destilation sous pression s'est présentée satisfaisante en ce qui concerne le rendement en éthanol. Cependant, celui-ci s'est montré légèrement inférieur à celui obtenu par destilation à la pression atmosphérique. Une économie d'énergie en forme de vapeur d'eau de plus de 40% a été le résultat de l'emploi de basse temperature pour le traitement de l'amidon de cassava et du procédé de destilation sous pression dans la production d'éthanol à partir de racines de cassava. Le rendement en éthanol anhydre a varié selon le contenue en amidon de la matière première, en oscillant entre 185 et 200 litres par tonne de racines de cassava.

     

Detection of nonribosomal peptide synthetase genes in Xylaria sp. BCC1067 and cloning of XyNRPSA

Nonribosomal peptides, synthesized by nonribosomal peptide synthetases (NRPS), are an important group of diverse bioactive fungal metabolites. Xylaria sp. BCC1067, which is known to produce a variety of biologically active metabolites, was studied for gene encoding NRPS by two different PCR-based methods and seven different NRPS fragments were obtained. In addition, screening a genomic library with an amplified NRPS fragment as a probe identified a putative NRPS gene named XyNRPSA. The functionality of XyNRPSA for the production of a corresponding metabolite was probed by gene insertion inactivation. Comparing the disrupting metabolite profile with that of the wild type led to the identification of a speculated metabolite. The crude extract of Xylaria sp. BCC1067 also exhibits antifungal activity against the human pathogens Candida albicans and Trichophyton mentagrophytes. However, the evaluation of biological activity of the XyNRPSA product suggests that it is neither a compound with antifungal activity nor a siderophore. In the vicinity of XyNRPSA, a second gene (named XyPtB) was identified. Its localization and homology to orfB of the ergot alkaloid biosynthetic gene cluster suggests that XyPtB may be involved in XyNRPSA product biosynthesis.     

Low Level of Sequence Diversity at Merozoite Surface Protein-1 Locus of Plasmodium ovale curtisi and P. ovale wallikeri from Thai Isolates

Background

The merozoite surface protein-1 (MSP-1) is a candidate target for the development of blood stage vaccines against malaria. Polymorphism in MSP-1 can be useful as a genetic marker for strain differentiation in malarial parasites. Although sequence diversity in the MSP-1 locus has been extensively analyzed in field isolates of Plasmodium falciparum and P. vivax, the extent of variation in its homologues in P. ovale curtisi and P. ovale wallikeri, remains unknown.

Methodology/Principal Findings

Analysis of the mitochondrial cytochrome b sequences of 10 P. ovale isolates from symptomatic malaria patients from diverse endemic areas of Thailand revealed co-existence of P. ovale curtisi (n = 5) and P. ovale wallikeri (n = 5). Direct sequencing of the PCR-amplified products encompassing the entire coding region of MSP-1 of P. ovale curtisi (PocMSP-1) and P. ovale wallikeri (PowMSP-1) has identified 3 imperfect repeated segments in the former and one in the latter. Most amino acid differences between these proteins were located in the interspecies variable domains of malarial MSP-1. Synonymous nucleotide diversity (π_S) exceeded nonsynonymous nucleotide diversity (π_N) for both PocMSP-1 and PowMSP-1, albeit at a non-significant level. However, when MSP-1 of both these species was considered together, π_S was significantly greater than π_N (p<0.0001), suggesting that purifying selection has shaped diversity at this locus prior to speciation. Phylogenetic analysis based on conserved domains has placed PocMSP-1 and PowMSP-1 in a distinct bifurcating branch that probably diverged from each other around 4.5 million years ago.

Conclusion/Significance

The MSP-1 sequences support that P. ovale curtisi and P. ovale wallikeri are distinct species. Both species are sympatric in Thailand. The low level of sequence diversity in PocMSP-1 and PowMSP-1 among Thai isolates could stem from persistent low prevalence of these species, limiting the chance of outcrossing at this locus.     

Curcumin Prevents Bile Canalicular Alterations in the Liver of Hamsters Infected with Opisthorchis viverrini

Opisthorchis viverrini infection causes inflammation and liver injury leading to periductal fibrosis. Little is known about the pathological alterations in bile canaliculi in opisthorchiasis. This study aimed to investigate bile canalicular alterations in O. viverrini-infected hamsters and to examine the chemopreventive effects of curcumin on such changes. Hamsters were infected with O. viverrini and one group of animals was fed with 1% dietary curcumin supplement. Animals were examined during the acute infection phase, days 21 and 30 post-infection (PI) and chronic infection phase (day 90 PI). Scanning electron microscopy revealed that in the infected group fed with a normal diet, bile canaliculi became slightly tortuous by 30 day PI and more tortuous at day 90 PI. Transmission electron microscopy showed a reduction in microvilli density of canaliculi starting at day 30 PI, with a marked loss of microvilli at day 90 PI. These ultrastructral changes were slightly seen at day 21 PI, which was similar to that found in infected animals fed with 1% curcumin-supplemented diet. Notably, curcumin treatment prevented the reduction of microvilli density, reduced the dilation of bile canaliculi, and decreased the tortuosity of the bile canaliculi relative to non-infected animals on a normal diet at days 30 and 90 PI. These results suggest that curcumin reduces alteration of bile canaliculi and may be a promising agent to prevent the onset of bile duct abnormalities induced by O. viverrini infection.     

Inflammation-induced protein carbonylation contributes to poor prognosis for cholangiocarcinoma

Carbonylation is an irreversible and irreparable protein modification induced by oxidative stress. Cholangiocarcinoma (CCA) is associated with chronic inflammation caused by liver fluke infection. To investigate the relationship between protein carbonylation and CCA progression, carbonylated proteins were detected by 2D OxyBlot and identified by MALDI-TOF/TOF analyses in pooled CCA tissues in comparison to adjacent nontumor tissues and normal liver tissues. We identified 14 highly carbonylated proteins in CCA tissues. Immunoprecipitation and Western blot analyses of individual samples confirmed significantly greater carbonylation of serotransferrin, heat shock protein 70-kDa protein 1 (HSP70.1), and α1-antitrypsin (A1AT) in tumor tissues compared to normal tissues. The oxidative modification of these proteins was significantly associated with poor prognoses as determined by the Kaplan-Meier method. LC-MALDI-TOF/TOF mass spectrometry identified R50, K327, and P357 as carbonylated sites in serotransferrin, HSP70.1, and A1AT, respectively. Moreover, iron accumulation was significantly higher in CCA tissues with, compared to those without, carbonylated serotransferrin. We conclude that carbonylated serotransferrin-associated iron accumulation may induce oxidative stress via the Fenton reaction, and the carbonylation of HSP70.1 with antioxidative property and A1AT with protease inhibitory capacity may cause them to become dysfunctional, leading to CCA progression.     

Role of extrinsic innervation in modulating nitrergic transmission in the canine ileocolonic region

The human colon can dilate, often to life-threatening proportions. Our aim was to explore nitrergic mechanisms underlying colonic dilation in conscious dogs with enterically isolated ileocolonic loops either extrinsically innervated (n = 4) or extrinsically denervated (n = 4). We recorded phasic pressures in ileum and ileocolonic sphincter (ICS), colonic tone, compliance, and relaxation during ileal distension. By NADPH-diaphorase histochemistry, we assessed effects of extrinsic denervation and enteric isolation on nitrergic fibers. Extrinsic denervation increased phasic pressures in ileum, ICS, and colon and abolished ICS and colonic relaxation in response to ileal distension. The nitric oxide synthase (NOS) inhibitor N(omega)-nitro-L-arginine (L-NNA) increased phasic pressures at all sites and ICS tone but did not abolish colonic relaxation during ileal distension in innervated loops. L-NNA reduced compliance and induced colonic high-amplitude propagated contractions in denervated loops. The NOS substrate donor L-arginine reversed effects of L-NNA. The number of NADPH-diaphorase fibers increased in both enterically isolated preparations. Nonnitrergic extrinsic nerve pathways mediate reflex colonic relaxation during ileal distension. Enteric isolation augments the number of NOS fibers, an effect not modified by extrinsic denervation.     

8-nitroguanine formation in the liver of hamsters infected with Opisthorchis viverrini

Nucleic acid damage by reactive nitrogen and oxygen species may contribute to the carcinogenesis associated with chronic infection and inflammation. We examined 8-nitroguanine and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) formation and nitric oxide (NO) production in hamsters infected with Opisthorchis viverrini (OV). Formation of 8-nitroguanine was assessed immunohistochemically with an antibody specific for 8-nitroguanine. 8-nitroguanine formation was found mainly in the cytoplasm and slightly in the nucleus of inflammatory cells and epithelial lining of bile duct at inflammatory areas in the liver. 8-nitroguanine immunoreactivity reached the highest intensity on day 30. A time profile of 8-nitroguanine formation was closely associated with that of plasma nitrate/nitrite. HPLC with an electrochemical detector revealed that the amount of 8-oxodG in the liver reached the maximal level on day 21. The mechanisms of 8-oxodG and 8-nitroguanine formation via O2*- and NO production triggered by OV infection were discussed in relation to cholangiocarcinoma development.     

Emergence and Characterization of Unusual DS-1-Like G1P[8] Rotavirus Strains in Children with Diarrhea in Thailand

The emergence and rapid spread of unusual DS-1-like G1P[8] rotaviruses in Japan have been recently reported. During rotavirus surveillance in Thailand, three DS-1-like G1P[8] strains (RVA/Human-wt/THA/PCB-180/2013/G1P[8], RVA/Human-wt/THA/SKT-109/2013/G1P[8], and RVA/Human-wt/THA/SSKT-41/2013/G1P[8]) were identified in stool specimens from hospitalized children with severe diarrhea. In this study, we sequenced and characterized the complete genomes of strains PCB-180, SKT-109, and SSKT-41. On whole genomic analysis, all three strains exhibited a unique genotype constellation including both genogroup 1 and 2 genes: G1-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2. This novel genotype constellation is shared with Japanese DS-1-like G1P[8] strains. Phylogenetic analysis revealed that the G/P genes of strains PCB-180, SKT-109, and SSKT-41 appeared to have originated from human Wa-like G1P[8] strains. On the other hand, the non-G/P genes of the three strains were assumed to have originated from human DS-1-like strains. Thus, strains PCB-180, SKT-109, and SSKT-41 appeared to be derived through reassortment event(s) between Wa-like G1P[8] and DS-1-like human rotaviruses. Furthermore, strains PCB-180, SKT-109, and SSKT-41 were found to have the 11-segment genome almost indistinguishable from one another in their nucleotide sequences and phylogenetic lineages, indicating the derivation of the three strains from a common origin. Moreover, all the 11 genes of the three strains were closely related to those of Japanese DS-1-like G1P[8] strains. Therefore, DS-1-like G1P[8] strains that have emerged in Thailand and Japan were assumed to have originated from a recent common ancestor. To our knowledge, this is the first report on whole genome-based characterization of DS-1-like G1P[8] strains that have emerged in an area other than Japan. Our observations will provide important insights into the evolutionary dynamics of emerging DS-1-like G1P[8] rotaviruses.