Non-ribosomal peptides produced by Brazilian cyanobacterial isolates with antimicrobial activity

Cyanobacterial strains isolated from terrestrial and freshwater habitats in Brazil were evaluated for their antimicrobial and siderophore activities. Metabolites of fifty isolates were extracted from the supernatant culture media and cells using ethyl acetate and methanol, respectively. The extracts of 24 isolates showed antimicrobial activity against several pathogenic bacteria and one yeast. These active extracts were characterized by Q-TOF/MS. The cyanobacterial strains Cylindrospermopsis raciborskii 339-T3, Synechococcus elongatus PCC7942, Microcystis aeruginosa NPCD-1, M. panniformis SCP702 and Fischerella sp. CENA19 provided the most active extracts. The 50 cyanobacterial strains were also screened for the presence of non-ribosomal peptide synthetase (NRPS) and polyketide synthase (PKS) genes and microcystin production. Putative fragment genes coding for NRPS adenylation domains and PKS keto-synthase domains were successfully PCR amplified from 92% and 80% of cyanobacterial strains, respectively. The potential therapeutical compounds siderophores were detected in five cyanobacterial isolates. Microcystin production was detected by ELISA test in 26% of the isolates. Further a protease inhibitor substance was detected by LC-MS/MS in the M. aeruginosa NPLJ-4 extract and the presence of aeruginosin and cyanopeptolin was confirmed by PCR amplification using specific primers, and sequenced. This screening study showed that Brazilian cyanobacterial isolates are a rich source of natural products with potential for pharmacological and biotechnological applications. (C) 2010 Elsevier GmbH. All rights reserved.

Current smoking and the risk of non-fatal myocardial infarction in the WHO MONICA Project populations

Background: Cohort studies have shown that smoking has a substantial influence on coronary heart disease mortality in young people. Population based data on non-fatal events have been sparse, however. Objective: To study the impact of smoking on the risk of non-fatal acute myocardial infarction (MI) in young middle age people. Methods: From 1985 to 1994 all non-fatal MI events in the age group 35 - 64 were registered in men and women in the WHO MONICA ( multinational monitoring of trends and determinants in cardiovascular disease) project populations ( 18 762 events in men and 4047 in women from 32 populations from 21 countries). In the same populations and age groups 65 741 men and 66 717 women participated in the surveys of risk factors ( overall response rate 72%). The relative risk of non-fatal MI for current smokers was compared with non-smokers, by sex and five year age group. Results: The prevalence of smoking in people aged 35 - 39 years who experienced non-fatal MI events was 81% in men and 77% in women. It declined with increasing age to 45% in men aged 60 - 64 years and 36% in women, respectively. In the 35 - 39 years age group the relative risk of non-fatal MI for smokers was 4.9 (95% confidence interval (CI) 3.9 to 6.1) in men and 5.3 ( 95% CI 3.2 to 8.7) in women, and the population attributable fractions were 65% and 55%, respectively. Conclusions: During the study period more than half of the non-fatal MIs occurring in young middle age people can be attributed to smoking.

A non-invasive method for silencing gene transcription in honeybees maintained under natural conditions

in the Apis mellifera post-genomic era, RNAi protocols have been used in functional approaches. However, sample manipulation and invasive methods such as injection of double-stranded RNA (dsRNA) can compromise physiology and survival. To circumvent these problems, we developed a non-invasive method for honeybee gene knockdown, using a well-established vitellogenin RNAi system as a model. Second instar larvae received dsRNA for vitellogenin (dsVg-RNA) in their natural diet. For exogenous control, larvae received dsRNA for GFP (dsGFP-RNA). Untreated larvae formed another control group. Around 60% of the treated larvae naturally developed until adult emergence when 0.5 mu g of dsVg-RNA or dsGFP-RNA was offered while no larvae that received 3.0 mu g of dsRNA reached pupal stages. Diet dilution did not affect the removal rates. Viability depends not only on the delivered doses but also on the internal conditions of colonies. The weight of treated and untreated groups showed no statistical differences. This showed that RNAi ingestion did not elicit drastic collateral effects. Approximately 90% of vitellogenin transcripts from 7-day-old workers were silenced compared to controls. A large number of samples are handled in a relatively short time and smaller quantities of RNAi molecules are used compared to invasive methods. These advantages culminate in a versatile and a cost-effective approach. (c) 2008 Elsevier Ltd. All rights reserved.

Teleportation in a non-inertial frame

In this work, we describe the process of teleportation between Alice in an inertial frame, and Rob who is in uniform acceleration with respect to Alice. The fidelity of the teleportation is reduced due to Davies-Unruh radiation in Rob's frame. In so far as teleportation is a measure of entanglement, our results suggest that quantum entanglement is degraded in non-inertial frames. We discuss this reduction in fidelity for both bosonic and fermionic resources.

Interaction of 10-(octyloxy) decyl-2-(trimethylammonium) ethyl phosphate with mimetic membranes and cytotoxic effect on leukemic cells

10-(Octyloxy) decyl-2-(trimethylammonium) ethyl phosphate (ODPC) is an alkylphospholipid that can interact with cell membranes because of its amphiphilic character. We describe here the interaction of ODPC with liposomes and its toxicity to leukemic cells with an ED-50 of 5.4, 5.6 and 2.9 pM for 72 h of treatment for inhibition of proliferation of NB4, U937 and K562 cell lines, respectively, and lack of toxicity to normal hematopoietic progenitor cells at concentrations up to 25 pM. The ED-50 for the non-malignant HEK-293 and primary human umbilical vein endothelial cells (HUVEC) was 63.4 and 60.7 mu M, respectively. The critical micellar concentration (CMC) of ODPC was 200 mu M. Dynamic light scattering indicated that dipalmitoylphosphatidylcholine (DPPC) liposome size was affected only above the CMC of ODPC. Differential calorimetric scanning (DCS) of liposomes indicated a critical transition temperature (T(c)) of 41.5 degrees C and an enthalpy (Delta H) variation of 7.3 kcal mol(-1). The presence of 25 mu M ODPC decreased T(c) and Delta H to 393 degrees C and 4.7 kcal mol(-1), respectively. ODPC at 250 mu M destabilized the liposomes (36.3 degrees C. 0.46 kcal mol(-1)). Kinetics of 5(6)-carboxyfluorescein (CF) leakage from different liposome systems indicated that the rate and extent of CF release depended on liposome composition and ODPC concentration and that above the CMC it was instantaneous. Overall, the data indicate that ODPC acts on in vitro membrane systems and leukemia cell lines at concentrations below its CMC, suggesting that it does not act as a detergent and that this effect is dependent on membrane composition. (C) 2010 Elsevier B.V. All rights reserved.

Non-diagonal solutions of the reflection equation for the trigonometric A((1)) (n-1) vertex model

We obtain a class of non-diagonal solutions of the reflection equation for the trigonometric A(n-1)((1)) vertex model. The solutions can be expressed in terms of intertwinner matrix and its inverse, which intertwine two trigonometric R-matrices. In addition to a discrete (positive integer) parameter l, 1 less than or equal to l less than or equal to n, the solution contains n + 2 continuous boundary parameters.

Reduced pH induces an inactive non-native conformation of the monomeric bothropstoxin-I (Lys49-PLA(2))

Bothropstoxin-I (BthTx-I), a Lys49-PLA(2) from Bothrops jararacussu venom, permeabilizes membranes by a non-hydrolytic Ca(2+)-independent mechanism. The BthTx-I showed activity against liposomes including 10% and 50% negatively charged lipids at pH 7.0, but not at pH 5.0. Nevertheless, ultracentrifugation and FRET demonstrated that at pH 5.0 the BthTx-I is bound to 50% negatively charged membranes. ANS binding identified a non-native monomeric conformation at pH 5.0, suggesting that tertiary structure alterations result in activity loss of the BthTx-I at low pH. (C) 2009 Elsevier Ltd. All rights reserved.

Involvement of dopaminergic mechanisms in the nucleus accumbens core and shell subregions in the expression of fear conditioning

The involvement of dopamine (DA) mechanisms in the nucleus accumbens (NAC) in fear conditioning has been proposed by many studies that have challenged the view that the NAC is solely involved in the modulation of appetitive processes. However, the role of the core and shell subregions of the NAC in aversive conditioning remains unclear. The present study examined DA release in these NAC subregions using microdialysis during the expression of fear memory. Guide cannulae were implanted in rats in the NAC core and shell. Five days later, the animals received 10 footshocks (0.6 mA, 1 s duration) in a distinctive cage A (same context). On the next day, dialysis probes were inserted through the guide cannulae into the NAC core and shell subregions, and the animals were behaviorally tested for fear behavior either in the same context (cage A) or in a novel context (cage B). Dialysates were collected every 5 min for 90 min and analyzed by high-performance liquid chromatography. The rats exhibited a significant fear response in cage A but not in cage B. Moreover, increased DA levels in both NAC subregions were observed 5-25 min after the beginning of the test when the animals were tested in the same context compared with accumbal DA levels from rats tested in the different context. These findings Suggest that DA mechanisms in both the NAC core and shell may play an important role in the expression of contextual fear memory. (c) 2008 Elsevier Ireland Ltd. All rights reserved.

Involvement of the midbrain tectum in the unconditioned fear promoted by morphine withdrawal

The midbrain rectum structures, dorsal periaqueductal gray (dPAG) and inferior colliculus (IC), are involved in the organization of fear and anxiety states during the exposure to dangerous stimuli. Since opiate withdrawal is associated with increased anxiety in both humans and animals, this study aimed to investigate the possible sensitization of the neural substrates of fear in the midbrain tectum and its influence on the morphine withdrawal-induced anxiety. For the production of drug withdrawal, rats received morphine injections (10 mg/kg; s.c.) twice daily during 10 days. Forty-eight hours after the interruption of the chronic treatment, independent groups were probed in the elevated plus-maze and open-field tests. Additional groups of animals were implanted with a bipolar electrode into the dPAG OF the IC and submitted to the electrical stimulation of these structures for the determination of the freezing and escape thresholds after 48 h of withdrawal. Our results showed that the morphine withdrawal promoted clear-cut levels of anxiety without the somatic signs of opiate withdrawal. Moreover, morphine-withdrawn rats had an increase in the reactivity to the electrical stimulation of the dPAG and the IC. These findings suggest that the increased anxiety induced by morphine withdrawal is associated with the sensitization of the neural substrates of fear in the dPAG and the IC. So, the present results give support to the hypothesis that withdrawal from chronic treatment with morphine leads to fear states possibly engendered by activation of the dPAG and IC, regardless of the production of somatic symptoms. (C) 2008 Elsevier B.V. All rights reserved.

C(alpha)-HOLDER CLASSICAL SOLUTIONS FOR NON-AUTONOMOUS NEUTRAL DIFFERENTIAL EQUATIONS

In this paper we discuss the existence of alpha-Holder classical solutions for non-autonomous abstract partial neutral functional differential equations. An application is considered.

Experience-induced preference for oviposition repellents derived from a non-host plant by a specialist herbivore

Foraging adults of phytophagous insects are attracted by host-plant volatiles and supposedly repelled by volatiles from non-host plants. In behavioural control of pest insects, chemicals derived from non-host plants applied to crops are expected to repel searching adults and thereby reduce egg laying. How experience by searching adults of non-host volatiles affects their subsequent searching and oviposition behaviour has been rarely tested. In laboratory experiments, we examined the effect of experience of a non-host-plant extract on the oviposition behaviour of the diamondback moth (DBM), Plutella xylostella, a specialist herbivore of cruciferous plants. Naive ovipositing DBM females were repelled by an extract of dried leaves of Chrysanthemum morifolium, a non-host plant of DBM, but experienced females were not repelled. Instead they were attracted by host plants treated with the non-host-plant extract and laid a higher proportion of eggs on treated than on untreated host plants. Such behavioural changes induced by experience could lead to host-plant range expansion in phytophagous insects and play an important role in determining outcome for pest management of some behavioural manipulation methods.

Identification of novel non-autonomous CemaT transposable elements and evidence of their mobility within the C. elegans genome

We describe here two new transposable elements, CemaT4 and CemaT5, that were identified within the sequenced genome of Caenorhabditis elegans using homology based searches. Five variants of CemaT4 were found, all non-autonomous and sharing 26 bp inverted terminal repeats (ITRs) and segments (152-367 bp) of sequence with similarity to the CemaT1 transposon of C. elegans. Sixteen copies of a short, 30 bp repetitive sequence, comprised entirely of an inverted repeat of the first 15 bp of CemaT4's ITR, were also found, each flanked by TA dinucleotide duplications, which are hallmarks of target site duplications of mariner-Tc transposon transpositions. The CemaT5 transposable element had no similarity to maT elements, except for sharing identical ITR sequences with CemaT3. We provide evidence that CemaT5 and CemaT3 are capable of excising from the C. elegans genome, despite neither transposon being capable of encoding a functional transposase enzyme. Presumably, these two transposons are cross-mobilised by an autonomous transposon that recognises their shared ITRs. The excisions of these and other non-autonomous elements may provide opportunities for abortive gap repair to create internal deletions and/or insert novel sequence within these transposons. The influence of non-autonomous element mobility and structural diversity on genome variation is discussed.

Primary Antiphospholipid Syndrome and Thyroid Involvement

Background: Data on thyroid involvement in primary antiphospholipid syndrome are scarce and inconclusive. Objectives: The aim of this study was to evaluate the frequency of thyroid dysfunction and antibodies in patients with primary antiphospholipid syndrome ( PAPS) and the association of these alterations with clinical and immunologic features. Methods: The study group included 50 PAPS patients (44 females) with a mean age of 39.7 +/- 11.5 years and mean disease duration of 77.3 +/- 63.5 months. Clinical data related to thyroid dysfunction and PAPS were obtained by chart review, patient interview, and clinical examination. Serum levels of TSH, free T4, antithyroglobulin antibody (TgAb), antithyroperoxidase antibody (TPOAb), thyroid receptor antibody (TRAb), and antiphospholipid autoantibodies were analyzed by standard techniques. Results: We found no hyperthyroidism among patients and found 22% (11 patients) with hypothyroidism in this sample. There were no differences between the latter patients and the euthyroid group about demographic findings, disease duration, thrombotic or obstetric events, and frequency of antiphospholipid antibodies as well as prevalence of thyroid auto antibodies. The prevalence of thyroid autoantibodies found was 6 patients (12%) with TgAb, 5 with TPOAb (10%), and 2 patients (4%) with both TgAb and TPOAb, comprising 18% of positivity of at least one of the auto antibodies. Conclusion: Hypothyroidism is present among 22% of PAPS patients and thyroid autoantibodies in 18% of them. These findings suggest a common pathophysiologic mechanism between antiphospholipid syndrome and autoimmune thyroid diseases.