The fate of the fusarium mycotoxin zearalenone in maize cell suspension cultures

The fusarium mycotoxin zearalenone was transformed in cell suspension cultures of Zea mays giving α- and β-zearalenol and the β-D-glu cos ides of zearalenone and α- and β-zearalenol. The structure of zearalenone-4-β-D-glucopyranoside was determined by liquid — chromatography-mass spectrometry and specific hydrolysis with β-glucosidase. α- and β-zearalenol and their glucosides were identified by co chromatography using tic and HPLC and glucosidase — treatment Up to 50% of the mycotoxin added was bound to a non extractable or “bound” residue fraction. After treating this residue by a sequential cell wall fractionation procedure, zearalenone was found to be bound mainly to starch, hemicellulose, and lignin fractions.     

Gene transfer is a major factor in bacterial evolution

Lateral gene transfer in four strains of Salmonella enterica has been assessed using genomic subtraction. Strain LT2 (subspecies I serovar Typhimurium) chromosomal DNA was used as target and subtracted by three subspecies I strains of serovars Typhimurium (S21), Muenchen (S71), Typhi (M229), and a subspecies V strain (M321). Data from probing random cosmids of LT2 DNA with preparations of the residual LT2 DNA after subtraction were used to estimate the amounts of LT2 DNA not able to hybridize to strains S21, S71, M229, and M321 to be in the range of 84-106, 191-355, 305-629, and 778-1,286 kb, respectively. Several lines of evidence indicate that most of this DNA is from genes not present in strain M321 and not from genes that have diverged in sequence. The amounts correlate with the divergence of the four strains as revealed by multilocus enzyme electrophoresis and sequence variation of housekeeping genes. Sequence of 39 of the fragments from the M321 subtracted residual LT2 DNA revealed only six inserts of known gene function with evidence of both gain and loss of genes during the development of S. enterica clones. Sixteen of the 39 segments have 45% or lower G+C content, below the species average, but over half are within the normal range for the species. We conclude that even within a species, clones may differ by up to 20% of chromosomal DNA, indicating a major role for lateral transfer, and that on the basis of G+C content, a significant proportion of the DNA is from distantly related species.      

Does small-sided-games’ court area influence metabolic,perceptual, and physical performance parameters of young elite basketball players?

The purpose of this study was to investigate the effect of court size on physiological responses and physical performance of young elite basketball players. Twelve male basketball players (18.6 ± 0.5 years; 88.8 ± 14.5 kg; 192.6 ± 6.5 cm) from an under-19 team performed two small-sided games (matches) with different court areas (28x15 m and 28x9 m; 28x15 and 28x9 protocols). The number of players (3x3) was kept the same in each protocol. The players performed a repeated-sprint ability (RSA) test before and after each match. Blood lactate concentration was collected before (pre) and after (post) the matches, and the session rating of perceived exertion (session-RPE) was determined 30 minutes after the match. Best and mean time in the RSA test were not different between the 28x15 and the 28x9 match protocols (p > 0.05). A significant difference was observed for lactate concentration from pre- to post-match (p < 0.05) in both protocols (28x15 and 28x9); however, there was no significant interaction between protocols. A similar session-RPE mean score (28x15: 7.2 ± 1.4 and 28x9: 6.6 ± 1.4) was detected for both protocols (p > 0.05, ES=0.41). In summary, the results of the current study suggest that the different court areas induced similar responses. Although there was no significant difference in effort perception, players tended to perceive a greater effort in the larger court size.     

Signatures of miR-181a on the Renal Transcriptome and Blood Pressure

MicroRNA-181a binds to the 3′ untranslated region of messenger RNA (mRNA) for renin, a rate-limiting enzyme of the renin-angiotensin system. Our objective was to determine whether this molecular interaction translates into a clinically meaningful effect on blood pressure and whether circulating miR-181a is a measurable proxy of blood pressure. In 200 human kidneys from the TRANScriptome of renaL humAn TissuE (TRANSLATE) study, renal miR-181a was the sole negative predictor of renin mRNA and a strong correlate of circulating miR-181a. Elevated miR-181a levels correlated positively with systolic and diastolic blood pressure in TRANSLATE, and this association was independent of circulating renin. The association between serum miR-181a and systolic blood pressure was replicated in 199 subjects from the Genetic Regulation of Arterial Pressure of Humans In the Community (GRAPHIC) study. Renal immunohistochemistry and in situ hybridization showed that colocalization of miR-181a and renin was most prominent in collecting ducts where renin is not released into the systemic circulation. Analysis of 69 human kidneys characterized by RNA sequencing revealed that miR-181a was associated with downregulation of four mitochondrial pathways and upregulation of 41 signaling cascades of adaptive immunity and inflammation. We conclude that renal miR-181a has pleiotropic effects on pathways relevant to blood pressure regulation and that circulating levels of miR-181a are both a measurable proxy of renal miR-181a expression and a novel biochemical correlate of blood pressure.     

Plant responses to elevated CO<Subscript>2</Subscript> concentration at different scales: leaf,whole plant,canopy, and population

Elevated CO₂ enhances photosynthesis and growth of plants, but the enhancement is strongly influenced by the availability of nitrogen. In this article, we summarise our studies on plant responses to elevated CO₂. The photosynthetic capacity of leaves depends not only on leaf nitrogen content but also on nitrogen partitioning within a leaf. In Polygonum cuspidatum, nitrogen partitioning among the photosynthetic components was not influenced by elevated CO₂ but changed between seasons. Since the alteration in nitrogen partitioning resulted in different CO₂-dependence of photosynthetic rates, enhancement of photosynthesis by elevated CO₂ was greater in autumn than in summer. Leaf mass per unit area (LMA) increases in plants grown at elevated CO₂. This increase was considered to have resulted from the accumulation of carbohydrates not used for plant growth. With a sensitive analysis of a growth model, however, we suggested that the increase in LMA is advantageous for growth at elevated CO₂ by compensating for the reduction in leaf nitrogen concentration per unit mass. Enhancement of reproductive yield by elevated CO₂ is often smaller than that expected from vegetative growth. In Xanthium canadense, elevated CO₂ did not increase seed production, though the vegetative growth increased by 53%. As nitrogen concentration of seeds remained constant at different CO₂ levels, we suggest that the availability of nitrogen limited seed production at elevated CO₂ levels. We found that leaf area development of plant canopy was strongly constrained by the availability of nitrogen rather than by CO₂. In a rice field cultivated at free-air CO₂ enrichment, the leaf area index (LAI) increased with an increase in nitrogen availability but did not change with CO₂ elevation. We determined optimal LAI to maximise canopy photosynthesis and demonstrated that enhancement of canopy photosynthesis by elevated CO₂ was larger at high than at low nitrogen availability. We also studied competitive asymmetry among individuals in an even-aged, monospecific stand at elevated CO₂. Light acquisition (acquired light per unit aboveground mass) and utilisation (photosynthesis per unit acquired light) were calculated for each individual in the stand. Elevated CO₂ enhanced photosynthesis and growth of tall dominants, which reduced the light availability for shorter subordinates and consequently increased size inequality in the stand.     

激光及γ射线对有丝分裂染色体畸变感应现象的比较

波长514nm的激光照射可用于研究激光导致有丝分裂染色体畸变的效应。本文提供了一种新的辐照系统,能用于研究突变的感应现象,并与从γ-线辐射源获得的结果进行了比较。 Abstract:Laser irradiation at wavelength 514 nm was used to study the effect of lasers in inducing chromosomal aberrations at mitosis.This study offers a new radiation system which could be used for the induction of mutations.Results are compared with those obtained from studies using γ-rays as irradiation source.     

Diversity of Bacteria in the Marine Sponge Aplysina fulva in Brazilian Coastal Waters

Microorganisms can account for up to 60% of the fresh weight of marine sponges. Marine sponges have been hypothesized to serve as accumulation spots of particular microbial communities, but it is unknown to what extent these communities are directed by the organism or the site or occur randomly. To address this question, we assessed the composition of specific bacterial communities associated with Aplysina fulva, one of the prevalent sponge species inhabiting Brazilian waters. Specimens of A. fulva and surrounding seawater were collected in triplicate in shallow water at two sites, Caboclo Island and Tartaruga beach, Búzios, Brazil. Total community DNA was extracted from the samples using “direct” and “indirect” approaches. 16S rRNA-based PCR-denaturing gradient gel electrophoresis (PCR-DGGE) analyses of the total bacterial community and of specific bacterial groups—Pseudomonas and Actinobacteria—revealed that the structure of these assemblages in A. fulva differed drastically from that observed in seawater. The DNA extraction methodology and sampling site were determinative for the composition of actinobacterial communities in A. fulva. However, no such effects could be gleaned from total bacterial and Pseudomonas PCR-DGGE profiles. Bacterial 16S rRNA gene clone libraries constructed from directly and indirectly extracted DNA did not differ significantly with respect to diversity and composition. Altogether, the libraries encompassed 15 bacterial phyla and the candidate division TM7. Clone sequences affiliated with the Cyanobacteria, Chloroflexi, Gamma- and Alphaproteobacteria, Actinobacteria, Bacteroidetes, and Acidobacteria were, in this order, most abundant. The bacterial communities associated with the A. fulva specimens were distinct and differed from those described in studies of sponge-associated microbiota performed with other sponge species.The phylum Porifera (sponges) consists of benthic (sessile) organisms that occur primarily in marine environments at different depths (26). Sponges are classified into three groups, namely, the Calcarea (calcareous sponges), Hexactinellida (glass sponges), and Demospongiae (5, 26). The group Demospongiae, also called demosponges, encompasses 95% of the ca. 5,500 living sponge species described thus far (5). As typical filter feeders, demosponges are the prime bacterial filters of the sea. They are capable of pumping thousands of liters of water per day (23), using prokaryotic microorganisms as the main source of food (1, 43, 47). In addition to demosponges feeding on microorganisms, the presence of bacteria in high density in internal sponge layers (mesohyl) indicates that a selective process favoring particular prokaryotes, involving microbe-sponge interactions, is likely to occur (64). Furthermore, the dawn of the interactions between Prokarya and higher organisms may actually lie in the demosponges, whose origin is estimated to date back to 550 million years ago (5, 33).Putative interactions between demosponges and microorganisms, presumably mostly consisting of Bacteria and Archaea, were first demonstrated by transmission electron microscopy (TEM), where high amounts of microorganisms were observed in the mesohyl (1, 14, 16, 64). Hence, these bacterium-rich sponges have been termed “bacteriosponges” (46). While investigating 11 taxonomically different demosponges using TEM, Vacelet and Donadey (64) identified two different sponge types in respect of their association with bacteria. Sponges with thick mesohyl contained abundant, dense, and morphologically diverse microbial communities (i.e., bacteriosponge), while those with a well-developed aquiferous system and low-density mesohyl contained few bacterial cells and typically only single bacterial morphotypes. The two types have recently been called “high-microbial-abundance” (HMA) and “low-microbial-abundance” (LMA) sponges, respectively (23). In HMA sponges, bacterial densities may reach 10⁸ to 10¹⁰ bacterial cells per g (wet weight) of sponge, exceeding seawater concentrations by 2 to 4 orders of magnitude (15, 23). Based on the analysis of 16S rRNA genes, over 15 bacterial phyla have thus far been reported to occur in association with marine sponges (11, 23, 56). Among these are typical sponge-associated bacteria such as members of the Cyanobacteria, Chloroflexi, Proteobacteria, Acidobacteria, Verrucomicrobia, and the candidate phyla “Poribacteria” and TM6 (14, 30, 51, 56, 60, 68).Increasing research interest in the sponge-associated microbiota has emerged in the past few years, mainly due to the in spongium production of an enormous diversity of biologically active secondary metabolites (56). Recent studies suggest that certain bioactive compounds retrieved from marine sponges—such as complex polypeptides and nonribosomal peptides—are likely to be synthesized by the symbiont bacteria (27, 41, 42). Such bioactive secondary metabolites offer great promise for use in biotechnology and medicine (3, 22, 27, 41, 42, 51, 59). In particular, cytotoxic compounds, i.e., antitumoral substances and polyketides, may find application in anticancer therapies (13, 42, 51). Recent investigations revealed the presence of dibromotyrosine-derived metabolites in Aplysina fulva (Pallas, 1766) specimens collected along the Brazilian shore (39). However, a putative role of microbial symbionts in the production of such metabolites, commonly found to display biological activity, remains to be evaluated.Despite the global-scale occurrence of sponges in Earth''s marine ecosystems, the investigation of their associated bacterial communities has thus far been restricted only to certain areas (1, 11, 13, 14, 27, 54, 58, 68). To our knowledge, no studies have been conducted, to date, on sponge-associated microbes in subtropical, South Atlantic open shore waters. In the present study, we assess the diversity and composition of the bacterial community associated with the demosponge A. fulva collected at two different sites at the Brazilian shore. A suite of tools, ranging from plate count estimations and TEM to sponge DNA-based analyses of bacterial 16S rRNA genes, was used. We hypothesized that a distinct bacterial community occurs in A. fulva, which is different from that in the surrounding bulk water, as well as from those in other sponge species.