Hydride-mediated reduction of 2,4,6-trinitrotoluene by yeasts as the way to its deep degradation

Broad screening of microorganisms from natural and anthropogenic ecological niches has revealed strains Candida sp. AN-L15 and Geotrichum sp. AN-Z4 which transform 2,4,6-trinitrotoluene (TNT) via alternative pathways (with the domination of hydride ion-mediated reduction of the aromatic ring) and produce relatively high amounts of nitrites. According to the spectrophotometry data, the hydride attack of TNT by Candida sp. AN-L15 and Geotrichum sp. AN-Z4 grown at pH 5.0-8.0 leads to the mono- and dihydride complexes of TNT (H(-)-TNT and 2H(-)-TNT, respectively) and to protonated forms of the latter. Analysis by HPLC, GC-mass spectrometry, and ion chromatography revealed the products of deep conversion of TNT. The growth of the yeast strains in a weakly acidic medium with TNT (440 microM) is accompanied by formation of 2,4-dinitrotoluene (2,4-DNT, up to 18.2 microM). Together with accumulation of nitrites (up to 76.0 microM, depending on pH of the medium), these findings demonstrate the capacity of both strains for TNT denitration. Formation of 2,4-DNT reflects the realization of one of the possible mechanisms of TNT ortho-nitro group elimination and switching over to the pathways of metabolism of dinitrotoluenes, which are much more easily biodegradable than TNT. Simultaneously with the dominating TNT hydride attack, the mechanism of 4- and 6-electron reduction of the nitro group also functions in Candida sp. AN-L15 and Geotrichum sp. AN-Z4. Realization of the studied mechanisms of TNT transformation under growth of Candida sp. AN-L15 on n-alkane is important for bioremediation in the cases of combined pollution by oil products and explosives.     

Quest for wine yeasts—An old story revisited

Numerous studies have described the yeast biota of grapes, and grape must in order to understand better the succession of yeasts during fermentation of wine. The origin of the wine yeasts has been rather controversial. By using more elaborate isolation methods, classical genetic analysis and electrophoretic karyotyping of monosporic clones, with this study, credible proof now exists that the vineyard is the primary source for the wine yeasts and that strains found on the grapes can be followed through the fermentation process.     

The environmental significance of algae in the mi Llandovery succession of the central Oslo Region

Girvanella , micritization phenomena and the dasycladacean alga Cyclocrinites are found in the middle Llandovery succession of the central Oslo Region. Both Girvanella and micritization phenomena occur in carbonate-dominated sequences where sedimentary structures and associated faunas suggest depositional environments above normal wave base. In contrast, Cyclocrinites occurs in shale-dominated sequences where other evidence suggests quiet, deep-water environments. We suggest that Cyclocrinites would not normally be preserved in situ in its life environment in relatively turbulent shallow waters. Preservation most commonly resulted from post mortem transport into low-energy muddy environments devoid of in situ algal activity. The resultant fossil is a flattened cast of this originally spherical alga.     

Insecticidal effects of selected biological control agents on the larvae of Plutella xylostella (Lepidoptera: Plutellidae)

To identify a more effective and safe biological control agent against a common cabbage pest, Plutella xylostella (L.) (Lepidoptera: Plutellidae), the insecticidal effects of selected biological agents were evaluated. The highest insecticidal effects determined were 100, 73.5, 45.5, 47 and 55.3% using toxin HD‐1 (isolated from the Harry Dumagae strain of Bacillus thuringiensis), toxin BTS‐1 (isolated from the tenebrionis strain of B. thuringiensis), B. thuringiensis Berliner, B. thuringiensis israelensis and B. thuringiensis kurstaki, respectively.     

Effects of four Bacillus spp. of soil origin on the Colorado potato beetle Leptinotarsa decemlineata (Say)

Four species of Bacillus were isolated from soil in an effort to find safe, effective and alternative biological control agents against plant pests. These bacteria were identified as Bacillus pumilus, Bacillus sphaericus, Bacillus megaterium and Bacillus cereus on the basis of fatty acid methyl ester analysis and carbon utilization profiles by using Microbial Identification and Biolog Microplate Systems. Laboratory experiments carried out to determine the insecticidal activities of these isolates showed that B. pumilus caused 95.7 and 26.7% mortality and B. sphaericus caused 74.5 and 23.3% mortality of Leptinotarsa decemlineata larvae and adults, respectively. B. cereus and B. megaterium showed 51.1 and 29.7%, respectively, of L. decemlineata larvae. This study presents at least two Turkish isolates from the genus Bacillus showing high insecticidal activity against L. decemlineata.     

Participation of oxygen in the bacterial transformation of 2,4,6-trinitrotoluene

The exposure of Bacillus cereus ZS18 cell suspensions to 2,4,6-trinitrotoluene (TNT) in the absence of other oxidizable substrates increases oxygen uptake, exceeding the basal level of respiration of the bacterium 1.5- and 2-fold with 50 and 100 mg/liter of TNT, respectively. The interaction of both living and to less extent dead bacterial cells with TNT results in the accumulation of superoxide anion (O2*-) in the extracellular medium, which was revealed by the EPR spectroscopy. The accumulation of O2*- decreased by 50-70% in the presence of Cu,Zn-superoxide dismutase of animal origin. In the presence of living bacterial cells, the level of TNT decreased progressively, yielding hydroxylaminodinitrotoluenes together with O2*-. In the presence of heat-killed cells, a moderate decrease in TNT was observed, and the appearance of O2*- was not accompanied by the production of any detectable TNT metabolites. Chelating agents inhibited the transformation of TNT and decreased the formation of O2*-. The demonstrated generation of O2*- during the interaction of TNT with K4[Fe(CN)6] together with the observed effects of chelating agents suggest the participation of iron in the one-electron reduction of TNT and the functioning of an extracellular redox cycle with the involvement of molecular oxygen.     

Effects of the afferent stimulation on neurons in the medial septal region slices and their modulation by biologically active compounds in hibernating and waking ground squirrels

Responses of the medial septal (MS-DB) neurons to electrical stimulation of the medial forebrain bundle (MFB) and their modulation by some neuropeptides and monoamines were investigated in brain slices taken from two groups of ground squirrels-hibernating (HGS) and waking (WGS). Electrical stimulation evoked mostly inhibitory effects of various duration. Besides, responses by phase reset of the background rhythmic bursts and short-latency single spike responses were observed. The neuropeptides identified in the brain of hibernators differentially and reversibly modulated responses even in those neurons where they did not influence the level and pattern of the background activity. Effects of the peptides were state-dependent. E.g., the peptide TSKYR increased the duration of inhibitory effects in the HGS but shortened them in the WGS, while TSKY which had low efficacy in the HGS, increased the duration of inhibition in the WGS. Dipeptide DY depressed inhibitory components and augmented excitatory components of responses in the HGS but was much less effective in the WGS. Effects of noradrenaline and serotonin had stronger correlation with their influence on spontaneous activity. It is suggested that endogenous substances provide for the increased latent excitability and reactivity of the MS-DB neurons during seasonal hibernation. Thus, the MS-DB may function as a "sentry post" participating in signal detection and urgent arousal during hibernation.     

Proteome–Metabolome Profiling of Ovarian Cancer Ascites Reveals Novel Components Involved in Intercellular Communication

Ovarian cancer ascites is a native medium for cancer cells that allows investigation of their secretome in a natural environment. This medium is of interest as a promising source of potential biomarkers, and also as a medium for cell–cell communication. The aim of this study was to elucidate specific features of the malignant ascites metabolome and proteome. In order to omit components of the systemic response to ascites formation, we compared malignant ascites with cirrhosis ascites. Metabolome analysis revealed 41 components that differed significantly between malignant and cirrhosis ascites. Most of the identified cancer-specific metabolites are known to be important signaling molecules. Proteomic analysis identified 2096 and 1855 proteins in the ovarian cancer and cirrhosis ascites, respectively; 424 proteins were specific for the malignant ascites. Functional analysis of the proteome demonstrated that the major differences between cirrhosis and malignant ascites were observed for the cluster of spliceosomal proteins. Additionally, we demonstrate that several splicing RNAs were exclusively detected in malignant ascites, where they probably existed within protein complexes. This result was confirmed in vitro using an ovarian cancer cell line. Identification of spliceosomal proteins and RNAs in an extracellular medium is of particular interest; the finding suggests that they might play a role in the communication between cancer cells. In addition, malignant ascites contains a high number of exosomes that are known to play an important role in signal transduction. Thus our study reveals the specific features of malignant ascites that are associated with its function as a medium of intercellular communication.Ovarian cancer is the sixth most frequently occurring cancer among the gynecological cancers and accounts for about 5% of all new female cancer cases according to the 2012 data (World Health Organization International Agency for Research on Cancer www.globocan.iarc.fr). Epithelial ovarian cancer registered in 90% of ovarian cancer cases. The rate of mortality from ovarian cancer holds first place among the other gynecological cancers, largely because of the asymptomatic progression of the disease, especially at its early stages, and a lack of adequate screening tests, which leads to late detection, typically only after the cancer has spread to adjacent structures. In such a case, the five-year survival rate is only 25% to 40%, whereas it can be as high as 90% if the cancer is diagnosed early. Unfortunately, ovarian cancer is diagnosed early in less than 20% of the total number of cases (International Agency for Research on Cancer). The main methods for primary diagnostics include transvaginal ultrasound and blood biomarker analyses such as with cancer antigen 125 (CA125),¹ epididymis protein-4 (HE4), and the OVA1 multiparametric (CA125, β2-microglobulin, transferrin, and apolipoprotein A1) tests. The OVA1 test is mainly applied to evaluate the malignancy of a tumor-like pelvic mass, and the other two markers are used to monitor disease progress and estimate treatment efficacy, as they are not highly specific for ovarian cancer and thus produce a high percentage of false-positive results (1). Therefore, the search for specific and sensitive markers for the early diagnosis of ovarian cancer is an urgent problem, although the development of new, efficient methods for treatment of the disease at late stages also remains of critical importance.One of the symptoms associated with late-stage ovarian cancer is excessive fluid accumulation in the abdominal cavity, known as ascites. Mechanisms of malignant ascites formation involve lymph obstruction, activation of mesothelial cells as a result of the metastatic process, and increased vessel permeability due to the secretion of growth factors (2, 3). Therefore, malignant ascites is enriched by tumor cells and soluble growth factors that may be associated with the processes of invasion and metastasis. Thus, ascites provides a native medium for cancer cells and creates an opportunity to investigate the ovarian cancer cell secretome in its natural environment (as distinct from cancer cell cultures in vitro) (2).Omics studies enable us to understand physiological information at different levels (4–7). Considering the highly diverse features of information obtained from each omics platform, one could expect that combinations of different omics should provide highly comprehensive views on special features of the cancer cell secretome. Studies of ascites with the use of omics technologies could not only help us understand the peculiarities of the vital activity of cancer cells in the organism, but also elaborate new therapeutic methods. However, until now, proteomic studies of ovarian cancer ascites have been exceptionally directed at the search for potential biomarkers of this cancer (3, 8–10). Investigation of ascites is also interesting beyond the protein level. In particular, small molecules—metabolites—are known to be involved in intercellular communication. However, in metabolome studies, to our knowledge, metabolites from ovarian cancer ascites have not been explored at all; only metabolomic analysis of urine and serum has been described in the literature for this type of cancer (11–13).It is important to note that ascites accumulation can be caused by various pathologies—for example, liver cirrhosis (81% of all cases), heart diseases (2%), tuberculosis (3%), and 10% of all cases associated with malignancy (10%). The most common cancer associated with ascites is ovarian cancer, accounting for 38% of malignant ascites occurring in females (2). In this study, we compared ascites of different etiologies, formed in the course of ovarian cancer and portal alcoholic cirrhosis. Thus, we not only extended our knowledge of the protein composition and filled in gaps regarding the metabolome, but also elucidated specific features of malignant ascites composition.     

Complete intra-annual cycle of leaf area index in a Platanus orientalis L. stand

Leaf area index (LAI) analysis of deciduous forest trees is usually restricted to seasonal monitoring involving the assessment of distinct leaf phenological stages within definite time intervals of the year. However, continuous LAI monitoring that includes entire leaf periods is necessary to define the ecophysiological characteristics of deciduous trees. Therefore, this study investigated the intra-annual cycle of the LAI for a Platanus orientalis L. stand in the Bart?n watershed of Turkey. A complete cycle involves three periods: foliation, stable, and defoliation. The foliation period comprises budburst, leaf emergence and flushing sessions, whereas the defoliation period consists of leaf senescence and leaf fall sessions. The stable period is in between these two periods when LAI values are at a climax around maximum. Eight points were determined in the field for the analysis of LAI by a hemispherical photography technique. Over a relatively frequent schedule, photographs were taken almost weekly during the foliation period. Both weekly and approximate monthly photographs were applied during the stable period. Finally, near-monthly photographs were taken for the defoliation period. The foliation period lasted for about 1.5 months from mid-April to May with the mean LAI reaching from 0.16 up to 2.38. Mean LAI was between 2.38 and 2.47 for a stable period over 2 months (June and July). For the defoliation period, mean LAI dropped from 2.42 down to 0.35 over 5 months from August to December. The total foliated period was more than 8 months, which is relatively long for a temperate forest. In addition, correlations between mean LAI and maximum, mean and minimum temperatures were highly significant (P < 0.01) with coefficients (r) of 0.79, 0.90 and 0.93, respectively. By describing the intra-annual LAI pattern, this study fills a gap in the literature on the phenology of Platanus orientalis L.