Photocatalytic Degradation of Emerging Contaminants: Artificial Sweeteners

Artificial sweeteners are food additives widely used, mainly in reduced sugar or sugar-free foods and beverages. Acesulfame potassium (ACE-K) and sodium saccharin (SAC) are among the most widely consumed sweeteners worldwide. These compounds when ingested are not metabolized by the body, being excreted unchanged. They arrive at treatment plants, where they are partially degraded and consequently released directly into water bodies. For this reason, artificial sweeteners have been detected in the most diverse aquatic environments, being recognized as emerging contaminants. In this work, aqueous solutions of ACE-K and SAC, submitted to heterogeneous photocatalysis (TiO₂/UV-A) for 60 min, showed degradations of more than 99% and maximum mineralization of 57% for ACE-K and 49% for SAC. The effects of certain variables were evaluated, with pH having a greater influence on the degradation of acesulfame and the mass of semiconductor on that of saccharin. The degradation of ACE-K and SAC followed a pseudo-first-order kinetic model according to the Langmuir–Hinshelwood model. Assays using Artemia salina as the test organism demonstrated the low toxicity of the photocatalyzed solutions of ACE-K and SAC. The contribution of different reactive species to the photocatalysis was investigated using specific radical inhibitors; the results indicate that singlet oxygen (¹O₂) has a fundamental role in the photocatalytic degradation of ACE-K and SAC.

Open image in new window

Graphical Abstract ?

     

Feasibility of Cordia trichotoma (Vell.) wood and its by-products for particleboard manufacturing

The wood panel industry uses a large volume of wood and it is essential to research the use of new tree species for these types of products. As such, the aim of this study was to evaluate the feasibility of Cordia trichotoma (Vell.) wood, both on its own and as a mixture with Pinus spp., as well as to understand the effect on particleboard quality when adding the species’ bark and shavings. The experimental design included nine treatments that assessed various mixture proportations of C. trichotoma and Pinus; for example, 10% bark, and 10% shavings of C. trichotoma with Pinus spp. and C. trichotoma particles, as well as mixtures of these two species in proportions of 25/75%, 50%/50%, and 75/25%. The results indicate that the Cordia trichotoma specie is technically feasible when manufacturing particleboards in pure form. The incorporation of bark (at 10% of the mixture) is also technically feasible. It is also feasible to use the shavings of C. trichotoma. In general, all treatments produced outputs that showed dimensional stability and mechanical strength statistically equal or higher than control treatments (Pinus spp.); thus, these products may be used for non-structural applications in dry and/or moist conditions.     

Correlations between the stability and adaptability statistics of popcorn cultivars

In plant breeding, correlations between the statistics of stability and adaptability of popcorn cultivars are not yet well understood. Therefore, the objectives of the present experiment was to investigate the correlations between s_di² \sigma_{\rm di}^{2} and b_i \beta_{\rm i} from Eberhart and Russell, ω_i from Wricke, \textS_\texti⁽¹⁾ {\text{S}}_{\text{i}}^{(1)} , \textS_\texti⁽²⁾ {\text{S}}_{\text{i}}^{(2)} and \textS_\texti⁽³⁾ {\text{S}}_{\text{i}}^{(3)} from Huehn, P_i from Lin and Binns and the rank-sum from Kang, and indicate the most reliable method for selecting popcorn cultivars. These statistics were estimated by data of crop yield from 19 Brazilian genotypes under 21 environments and popping expansion under 16 environments. The ω_i, \textS_\texti⁽¹⁾ {\text{S}}_{\text{i}}^{(1)} , \textS_\texti⁽²⁾ {\text{S}}_{\text{i}}^{(2)} , \textS_\texti⁽³⁾ {\text{S}}_{\text{i}}^{(3)} and s_di² \sigma_{\rm di}^{2} were positively and significantly correlated indicating that just one in these five statistics is sufficient for selecting stable genotypes although they were not correlated with the means of crop yield and popping expansion. The b_i \beta_{\rm i} was negatively and significantly correlated with P_i for crop yield indicating that the most adaptable genotypes tend to have the lowest estimates of P_i. Although P_i was not correlated with ω_i, \textS_\texti⁽¹⁾ {\text{S}}_{\text{i}}^{(1)} , \textS_\texti⁽²⁾ {\text{S}}_{\text{i}}^{(2)} , \textS_\texti⁽³⁾ {\text{S}}_{\text{i}}^{(3)} , or s_di² \sigma_{\rm di}^{2} statistics, it displayed positive correlation with the Index 1 (crop yield and popping expansion +  \textS_\texti⁽¹⁾ {\text{S}}_{\text{i}}^{(1)} rank) and Index 2 (crop yield and popping expansion + W_i) indicating that superior popcorn genotypes are also stable. Finally, both P_i and the rank-sum are useful statistics in breeding programmes where crop yield, popping expansion and stability are essential traits for selecting genotypes.     

Molecular typing and antimicrobial resistance of Salmonella enterica subspecies enterica serovar Choleraesuis isolates from diseased pigs in Japan

Salmonella enterica serovar Choleraesuis (S. Choleraesuis) isolates derived from diseased pigs in Japan during 2001 and 2005 were analyzed for biotype, based on H(2)S production and dulcitol fermentation, pulsed-field gel electrophoresis (PFGE) profile, and antimicrobial resistance profile. S. Choleraesuis biotype Choleraesuis (biotype Choleraesuis) was classified into one genotype, while varietas Kunzendorf (var. Kunzendorf) was classified into two genotypes. The isolates of var. Kunzendorf belonging to one genotype were isolated in a limited area of Japan. Variation in the antimicrobial resistance pattern was observed in isolates of both biotypes Choleraesuis and var. Kunzendorf. We have also shown that the PFGE profile was associated with the biotype and isolation region of each isolate.     

Biological and genetic diversity of plasmodiophorid-transmitted viruses and their vectors

About 20 species of viruses belonging to five genera, Benyvirus, Furovirus, Pecluvirus, Pomovirus and Bymovirus, are known to be transmitted by plasmodiophorids. These viruses have all positive-sense, single-stranded RNA genomes that consist of two to five RNA components. Three species of plasmodiophorids are recognized as vectors: Polymyxa graminis, P. betae, and Spongospora subterranea. The viruses can survive in soil within the long-lived resting spores of the vector. There are biological and genetic variations in both virus and vector species. Many of the viruses are causal agents of important diseases in major crops such as rice, wheat, barley, rye, sugar beet, potato, and groundnut. Control is dependent on the development of resistant cultivars. During the last half century, several virus diseases have rapidly spread worldwide. For six major virus diseases, we address their geographical distribution, diversity, and genetic resistance.     

水稻（Oryza sativa L．）苹果酸酶（OsNADP-ME3）基因在逆境下的表达特性研究

水稻苹果酸酶（NADP-ME）是多基因家族,由3个胞质型NADP-ME和1个质体型NADP—ME构成。本研究针对水稻胞质型成员（命名为NADP-ME3）（NM001061367）进行初步的功能解析。克隆获得的NADP-ME3基因的cDNA序列全长为2240bp,其中5’非翻译区为151bp,3’非翻译区为376bp,开放读码框（ORF）长1713bp,编码570个氨基酸。为研究NADP-ME3在逆境胁迫下的表达量变化,No．hemblot检测结果显示,在NaCl、NaHCO,和PEG胁迫条件下,NADP-ME3随胁迫处理时间的不同表达量呈现不同程度的变化,推断NADP-ME3可能与非生物胁迫有应答关系,将NADP-ME3转入拟南芥中并通过观察转基因拟南芥在非生物胁迫下表型变化,发现NADP-ME3能够在一定程度上提高植物对非生物胁迫的耐受性。     

Phylogenetic groups and cephalosporin resistance genes of Escherichia coli from diseased food-producing animals in Japan

A total of 318 Escherichia coli isolates obtained from different food-producing animals affected with colibacillosis between 2001 and 2006 were subjected to phylogenetic analysis: 72 bovine isolates, 89 poultry isolates and 157 porcine isolates. Overall, the phylogenetic group A was predominant in isolates from cattle (36/72, 50%) and pigs (101/157, 64.3%) whereas groups A (44/89, 49.4%) and D (40/89, 44.9%) were predominant in isolates from poultry. In addition, group B2 was not found among diseased food-producing animals except for a poultry isolate. Thus, the phylogenetic group distribution of E. coli from diseased animals was different by animal species. Among the 318 isolates, cefazolin resistance (minimum inhibitory concentrations: ≥32 μg/ml) was found in six bovine isolates, 29 poultry isolates and three porcine isolates. Of them, 11 isolates (nine from poultry and two from cattle) produced extended spectrum β-lactamase (ESBL). The two bovine isolates produced bla_CTX-M-2, while the nine poultry isolates produced bla_CTX-M-25 (4), bla_SHV-2 (3), bla_CTX-M-15 (1) and bla_CTX-M-2 (1). Thus, our results showed that several types of ESBL were identified and three types of β-lactamase (SHV-2, CTX-M-25 and CTX-M-15) were observed for the first time in E. coli from diseased animals in Japan.     

Multi-locus sequence typing of Salmonella enterica subsp. enterica serovar Enteritidis strains in Japan between 1973 and 2004

Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis) was responsible for a worldwide pandemic during the 1980s and 1990s; however, changes in the dominant lineage before and after this event remain unknown. This study determined S. Enteritidis lineages before and after this pandemic event in Japan using multilocus sequence typing (MLST). Thirty S. Enteritidis strains were collected in Japan between 1973 and 2004, consisting of 27 human strains from individual episodes, a bovine strain, a liquid egg strain and an eggshell strain. Strains showed nine phage types and 17 pulsed-field profiles with pulsed-field gel electrophoresis. All strains had homologous type 11 sequences without any nucleotide differences in seven housekeeping genes. These MLST results suggest that S. Enteritidis with the diversities revealed by phage typing and pulsed-field profiling has a highly clonal population. Although type 11 S. Enteritidis may exhibit both pleiotropic surface structure and pulsed-field type variation, it is likely to be a stable lineage derived from an ancestor before the 1980s and/or 1990s pandemic in Japan.