Interaction Between Polyamine and Nitric Oxide Signaling in Adaptive Responses to Drought in Cucumber

The effect of polyamines (PAs) on nitric oxide (NO) generation was investigated in cucumber (Cucumis sativus cv. Dar) primary leaves using bio-imaging with an NO-selective fluorophor, DAF-2DA. Seedlings pretreated with PAs and subjected to water deficit showed early (after 5 h) and transient NO production. The amplitude of the response depended on the form of the applied polyamine. Spermine (1.0 mM) and spermidine (1.0 mM) induced higher NO-dependent fluorescence compared with putrescine (1.0 mM) and the control. The NO production was blocked by tungstate, an inhibitor of nitrate reductase, and partially by an inhibitor of nitric oxide synthase (NOS-like) enzymes. NO donor administration preceding drought had no effect on endogenous PA levels but was positively correlated with an alleviation of water deficit-induced membrane permeability and lipid peroxidation. Application of 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO), a membrane-permeable NO scavenger, markedly reversed the NO donor effects. Similarly, pretreating seedlings with PAs resulted in lower ion leakage from the membrane and modified lipid peroxidation. The results indicate that NO may act downstream of PAs in cucumber seedlings under water stress.     

Ribonucleoside labeling with Os(VI): a methodological approach to evaluation of RNA methylation by HPLC-ICP-MS

Covalent modifications of nucleobases are thought to play an important role in regulating the functions of DNA and various cellular RNA types. Perhaps the best characterized is DNA methylation on cytosine (methyl tag attached to carbon 5 position) and such modification has also been detected in stable and long-lived RNA molecules. In this work, we propose a novel procedure enabling very sensitive quantification of methylcytidine and other ribonucleosides, based on reversed phase liquid chromatography with inductively coupled plasma mass spectrometry (ICP-MS) detection. The procedure relies on labeling ribose residues with osmium, by formation of a ternary complex between cis-diol ribose groups, hexavalent osmium (K(2)OsO(2)(OH)(4)) and tetramethylethylenediamine (TEMED). The derivatization reaction was carried out with 50?:?1 molar excess of Os to ribonucleoside, pH 4, for 2 h at room temperature. The structures of Os-labeled cytidine and methylcytidine were confirmed by electrospray ionization mass spectrometry. The separation of Os-labeled cytidine (C), uridine (U), 5-methylcytidine (5mC) and guanosine (G) was achieved on C18 column (Gemini, 150 × 3 mm, 5 μm) with isocratic elution (0.05% triethylamine + 6 mmol L(-1) ammonium acetate, pH 4.4: methanol (85?:?15)) and a total flow rate 0.6 mL min(-1). The column effluent was on-line introduced to ICP-MS (a model 7500 ce, Agilent Technologies) for specific detection at (189)Os. Calibration was performed within the concentration range 0-200 nmol L(-1) of each ribonucleoside and the analytical figures of merit were evaluated. For 100 μL injection, the detection limits for C, U, 5mC, G were 24, 38, 21 and 28 pmol L(-1), respectively. While introducing Os(vi)-TEMED to the column, it eluted in the dead volume and the detection limit for osmium was 20 pmol L(-1). The results obtained in this work might be helpful in the analysis of RNA digests, providing quantitative data on the ribonucleoside composition and RNA methylation (measured as the percentage of methylated cytidines with respect to total RNA cytidines).     

Pollen calendar for cracow (southern Poland), 1982–1991

Summary During 1982 – 1991 pollen deposition in the centre of Cracow (southern Poland) was investigated using the gravimetric method. 32 taxa of the 84 identified were taken into consideration, and nearly all of them can be allergenic. The beginning of mass pollen fall was observed in the second decade of March, and the third decade of September saw the completion of the yearly cycle of abundant appearance of pollen in the aeroplankton. Tree pollen dominates quantitatively.     

Xanthophyll cycle--a mechanism protecting plants against oxidative stress

Six different xanthophyll cycles have been described in photosynthetic organisms. All of them protect the photosynthetic apparatus from photodamage caused by light-induced oxidative stress. Overexcitation conditions lead, in the chloroplast, to the over-reduction of the NADP pool and production of superoxide, which can subsequently be metabolized to hydrogen peroxide or a hydroxyl radical, other reactive oxygen species (ROS). On the other hand, overexcitation of photosystems leads to an increased lifetime of the chlorophyll excited state, increasing the probability of chlorophyll triplet formation which reacts with triplet oxygen forming single oxygen, another ROS. The products of the light-dependent phase of xanthophyll cycles play an important role in the protection against oxidative stress generated not only by an excess of light but also by other ROS-generating factors such as drought, chilling, heat, senescence, or salinity stress. Four, mainly hypothetical, mechanisms explaining the protective role of xanthophyll cycles in oxidative stress are presented. One of them is the direct quenching of overexcitation by products of the light phase of xanthophyll cycles and three others are based on the indirect participation of xanthophyll cycle carotenoids in the process of photoprotection. They include: (1) indirect quenching of overexcitation by aggregation-dependent light-harvesting complexes (LHCII) quenching; (2) light-driven mechanisms in LHCII; and (3) a model based on charge transfer quenching between Chl a and Zx. Moreover, results of the studies on the antioxidant properties of xanthophyll cycle pigments in model systems are also presented.     

An acyl-CoA:cholesterol acyltransferase (ACAT)-related gene is involved in the accumulation of triacylglycerols in Saccharomyces cerevisiae

The major route for the synthesis of triacylglycerol (TAG) in yeast as well as in all TAG-accumulating organisms has been suggested to occur via the acylation of diacylglycerol (DAG) by acyl-CoA:diacylglycerol acyltransferase (DAGAT). Genes encoding DAGAT have been identified in both plant and animal tissues. These genes show strong sequence similarities to genes encoding acyl-CoA:cholesterol acyltransferase (ACAT). So far no Saccharomyces cerevisiae DAGAT gene has been published; however, two ACAT-like genes, ARE1 and ARE2, are present in the yeast genome. Both these genes have been suggested to be involved in the synthesis of sterol esters. We have now shown that the ARE1 gene in yeast also is involved in the synthesis of TAG, whereas the ARE2 gene is more specifically involved in the synthesis of sterol esters.     

Development of a PCR-based assay for rapid detection of class IIa bacteriocin genes

Aims: We have developed a PCR‐based assay using custom designed panel of primers which allows rapid detection of class IIa bacteriocin‐coding genes. To demonstrate the applicability of the developed assay, the method was applied on 40 metagenomic DNA preparations isolated from native microbiota of Polish artisanal cheeses produced in the Tatra Mountains. Methods and Results: The developed assay was designed on the basis of a large scale alignment of class IIa bacteriocin‐coding genes. A panel of seven primer pairs with confirmed ability to detect class IIa bacteriocin‐coding sequences was obtained. The following study has revealed a superb bacteriocinogenic potential of all forty analysed cheese samples. Conclusions: The majority of obtained sequences were lactic acid bacteria (LAB) related, although some sequences showed significant similarity to bacteriocin‐coding sequences present in non‐LAB bacteriocin producers. The results suggest that several potentially new bacteriocin‐coding sequences were found. Significance and Impact of the Study: The developed assay can be extremely helpful in establishing whether isolates from the environment of interest have a potential of synthesizing antilisterial class IIa bacteriocins. Application of the approach may represent a useful tool contributing to ecological studies looking for valuable probiotic, bacteriocinogenic microbiota developing in foods.     

Tuftsin--new analogues and properties

Tuftsin, a natural tetrapeptide of sequence TKPR, occuring in the blood of humans and other mammals, capable of stimulating certain white blood cells (monocytes, macrophages, and neutrophils), was isolated at Tufts University in 1970 by Najjar and Nishioka. Tuftsin is a compound with a wide spectrum of biological activities, notable enhances phagocytosis, immune response, bactericidal, tumoricidal and antifungal activities. This article concerns new analogues and properties of tuftsin.     

Altered Fronto-Temporal Functional Connectivity in Individuals at Ultra-High-Risk of Developing Psychosis

Background

The superior temporal gyrus (STG) is one of the key regions implicated in psychosis, given that abnormalities in this region are associated with an increased risk of conversion from an at-risk mental state to psychosis. However, inconsistent results regarding the functional connectivity strength of the STG have been reported, and the regional heterogeneous characteristics of the STG should be considered.

Methods

To investigate the distinctive functional connection of each subregion in the STG, we parcellated the STG of each hemisphere into three regions: the planum temporale, Heschl’s gyrus, and planum polare. Resting-state functional magnetic resonance imaging was obtained from 22 first-episode psychosis (FEP) patients, 41 individuals at ultra-high-risk for psychosis (UHR), and 47 demographically matched healthy controls.

Results

Significant group differences (in seed-based connectivity) were demonstrated in the left planum temporale and from both the right and left Heschl’s gyrus seeds. From the left planum temporale seed, the FEP and UHR groups exhibited increased connectivity to the bilateral dorsolateral prefrontal cortex. In contrast, the FEP and UHR groups demonstrated decreased connectivity from the bilateral Heschl’s gyrus seeds to the dorsal anterior cingulate cortex. The enhanced connectivity between the left planum temporale and right dorsolateral prefrontal cortex was positively correlated with positive symptom severity in individuals at UHR (r = .34, p = .03).

Conclusions

These findings corroborate the fronto-temporal connectivity disruption hypothesis in schizophrenia by providing evidence supporting the altered fronto-temporal intrinsic functional connection at earlier stages of psychosis. Our data indicate that subregion-specific aberrant fronto-temporal interactions exist in the STG at the early stage of psychosis, thus suggesting that these aberrancies are the neural underpinning of proneness to psychosis.     

A characterization of the egg capsules of Anacroneuria starki and A. talamanca (Plecoptera: Perlidae), with a suggestion about the distribution of stoneflies in the Tropics

In this study, the structure of egg capsules of two species of Neotropical Perlidae: Anacroneuria starki Fenoglio and Morisi (2001 a) and A. talamanca Stark (1998), were examined. Eggs were studied using a scanning electron microscope. A morphological characterization of these eggshells is presented: layers, attachment structures and other anatomical features are described. The egg capsules of the two species differ in some aspects, but both are characterized by thin-layered egg coverings (vitelline envelope, chorion and extrachorion). On the basis of these observations, the importance of eggshell structure for the biogeographical distribution of Plecoptera in the tropics is discussed. A key role for egg capsules in the adaptation process of Plecoptera to aquatic environments of the Neotropics is hypothesized.