Drying and storage of Melanoxylon brauna Schott. seeds

The objective of this work was to evaluate the sensitivity of Melanoxylon brauna Schott. tree legume seeds to desiccation and storage. In the drying experiment, the Melanoxylon brauna seeds were submitted to two drying conditions: a forced air circulation chamber (40.18 °C ± 0.13 and 28.48% ± 3.95 RH) and a silica gel desiccator (27.19 °C ± 1.28 and 26.19% ± 0.94 RH) for different times (0, 12, 24, 36, 72, and 144 hours). A completely randomized design in a 2 (drying methods) × 5 (drying times) factorial scheme plus control and 4 replications of 25 seeds was used. The following variables were evaluated before and after drying: seed moisture content, percentage of germinated seeds, germination speed index, percentage of mortality, normal and abnormal seedlings. In the storage experiment the seeds were divided into two batches: pre-dried (at 5.0% humidity) and without drying (control at 8.9% humidity). The seeds were then stored in plastic bags in three environments: refrigerator at 5 °C, freezer at -20 °C and room temperature (29 °C). The seeds were removed every four months and submitted to the humidity and germination test for 24 months. Data from this storage experiment were analyzed considering a randomized block design in a 2 (drying levels: presence and absence) × 3 (storage environments: refrigerator, freezer or room temperature) factorial scheme + 2 controls (with and without drying at baseline) and 4 repetitions of 25 seeds. Drying reduced initial seed water content from 8.9% to 5.0%, without loss of viability. Drying in the chamber at 40 °C was faster and more efficient than in silica gel. The results enable classifying the seeds of this species as orthodox, i.e. tolerant to desiccation. The fridge and freezer were efficient for storing the Melanoxylon brauna seeds up to 24 months, independent of previous drying, while storing the seeds at room temperature with previous drying makes them last longer than without drying, as the seeds can last up to 16 months with drying, or 12 months without drying.

Mechanisms of bacterial membrane permeabilization by crotalicidin (Ctn) and its fragment Ctn(15-34), antimicrobial peptides from rattlesnake venom

Crotalicidin (Ctn), a cathelicidin-related peptide from the venom of a South American rattlesnake, possesses potent antimicrobial, antitumor, and antifungal properties. Previously, we have shown that its C-terminal fragment, Ctn(15-34), retains the antimicrobial and antitumor activities but is less toxic to healthy cells and has improved serum stability. Here, we investigated the mechanisms of action of Ctn and Ctn(15-34) against Gram-negative bacteria. Both peptides were bactericidal, killing ∼90% of Escherichia coli and Pseudomonas aeruginosa cells within 90-120 and 5-30 min, respectively. Studies of ζ potential at the bacterial cell membrane suggested that both peptides accumulate at and neutralize negative charges on the bacterial surface. Flow cytometry experiments confirmed that both peptides permeabilize the bacterial cell membrane but suggested slightly different mechanisms of action. Ctn(15-34) permeabilized the membrane immediately upon addition to the cells, whereas Ctn had a lag phase before inducing membrane damage and exhibited more complex cell-killing activity, probably because of two different modes of membrane permeabilization. Using surface plasmon resonance and leakage assays with model vesicles, we confirmed that Ctn(15-34) binds to and disrupts lipid membranes and also observed that Ctn(15-34) has a preference for vesicles that mimic bacterial or tumor cell membranes. Atomic force microscopy visualized the effect of these peptides on bacterial cells, and confocal microscopy confirmed their localization on the bacterial surface. Our studies shed light onto the antimicrobial mechanisms of Ctn and Ctn(15-34), suggesting Ctn(15-34) as a promising lead for development as an antibacterial/antitumor agent.

siRNA-cell-penetrating peptides complexes as a combinatorial therapy against chronic myeloid leukemia using BV173 cell line as model

Chronic myeloid leukemia (CML) is a myeloproliferative disorder caused by a single gene mutation, a reciprocal translocation that originates the Bcr-Abl gene with constitutive tyrosine kinase activity. As a monogenic disease, it is an optimum target for RNA silencing therapy. We developed a siRNA-based therapeutic approach in which the siRNA is delivered by pepM or pepR, two cell-penetrating peptides (CPPs) derived from the dengue virus capsid protein. These peptides have a dual role: siRNA delivery into cells and direct action as bioportides, i.e. intracellularly bioactive CPPs, targetting cancer-related signaling processes. Both pepM and pepR penetrate the positive Bcr-Abl⁺ Cell Line (BV173). Five in silico designed anti-Bcr-Abl siRNA were selected for in vitro analysis after thorough screening. The Bcr-Abl downregulation kinetics (48h to 168h) was followed by quantitative PCR. The bioportide action of the peptide vectors was evaluated by genome-wide microarray analysis and further validated by testing BV173 cell cycle and cell proliferation monitoring different genes involved in housekeeping/cell stress (RPL13A, HPRT1), cell proliferation (ki67), cell apoptosis (Caspase 3 and Caspase 9) and cell cycle steps (CDK2, CCDN2, CDKN1A). Assays with a commercial transfection agent were carried out for comparison purposes. Maximal Bcr-Abl gene knockdown was observed for one of the siRNA when delivered by pepM at 120h. Both pepM and pepR showed downregulation effects on proliferative CML-related signaling pathways having direct impact on BV173 cell cycle and proliferation, thus reinforcing the siRNA effect by acting as anticancer molecules. With this work we show the therapeutic potential of a CPP shuttle that combines intrinsic anticancer properties with the ability to deliver functional siRNA into CML cell models. By such combination, the pepM-siRNA conjugates lowered Bcr-Abl gene expression levels more extensively than conventional siRNA delivery technologies and perturbed leukemogenic cell homeostasis, hence revealing their potential as novel alternative scaffolds for CML therapy.

Peptides as models for the structure and function of viral capsid proteins: Insights on dengue virus capsid

The structural organization of viral particles is among the most astonishing examples of molecular self-assembly in nature, involving proteins, nucleic acids, and, sometimes, lipids. Proper assembly is essential to produce well structured infectious virions. A great variety of structural arrangements can be found in viral particles. Nucleocapsids, for instance, may display highly ordered geometric shapes or consist in macroscopically amorphous packs of the viral genome. Alphavirus and flavivirus are viral genera that exemplify these extreme cases, the former comprising viral particles structured with a T = 4 icosahedral symmetry, whereas flavivirus capsids have no regular geometry. Dengue virus is a member of flavivirus genus and is used in this article to illustrate how viral protein-derived peptides can be used advantageously over full-length proteins to unravel the foundations of viral supramolecular assemblies. Membrane- and viral RNA-binding data of capsid protein-derived dengue virus peptides are used to explain the amorphous organization of the viral capsid. Our results combine bioinformatic and spectroscopic approaches using two- or three-component peptide and/or nucleic acid and/or lipid systems.

Receptors and routes of dengue virus entry into the host cells

Dengue is the most prevalent arthropod-borne viral disease, caused by dengue virus, a member of the Flaviviridae family. Its worldwide incidence is now a major health problem, with 2.5 billion people living in risk areas. In this review, we integrate the structural rearrangements of each viral protein and their functions in all the steps of virus entry into the host cells. We describe in detail the putative receptors and attachment factors in mammalian and mosquito cells, and the recognition of viral immunocomplexes via Fcγ receptor in immune cells. We also discuss that virus internalization might occur through distinct entry pathways, including clathrin-mediated or non-classical clathrin-independent endocytosis, depending on the host cell and virus serotype or strain. The implications of viral maturation in virus entry are also explored. Finally, we discuss the mechanisms of viral genome access to the cytoplasm. This includes the role of low pH-induced conformational changes in the envelope protein that mediate membrane fusion, and original insights raised by our recent work that supports the hypothesis that capsid protein would also be an active player in this process, acting on viral genome translocation into the cytoplasm.

Monitoring antibacterial permeabilization in real time using time-resolved flow cytometry

Despite the intensive study of antibiotic-induced bacterial permeabilization, its kinetics and molecular mechanism remain largely elusive. A new methodology that extends the concept of the live-dead assay in flow cytometry to real time-resolved detection was used to overcome these limitations. The antimicrobial activity of pepR was monitored in time-resolved flow cytometry for three bacterial strains: Escherichia coli (ATCC 25922), E. coli K-12 (CGSC Strain 4401) and E. coli JW3596-1 (CGSC Strain 11805). The latter strain has truncated lipopolysaccharides (LPS) in the outer membrane. This new methodology provided information on the efficacy of the antibiotics and sheds light on their mode of action at membrane-level. Kinetic data regarding antibiotic binding and lytic action were retrieved. Membrane interaction and permeabilization events differ significantly among strains. The truncation of LPS moieties does not hamper AMP binding but compromises membrane disruption and bacterial killing. We demonstrated the usefulness of time-resolved flow cytometry to study antimicrobial-induced permeabilization by collecting kinetic data that contribute to characterize the action of antibiotics directly on bacteria.

Cell-penetrating peptides: A tool for effective delivery in gene-targeted therapies

The current landscapes of novel therapeutic approaches rely mostly on gene-targeted technologies, enabling to fight rare genomic diseases, from infections to cancer and hereditary diseases. Although, reaching the action-site for this novel treatments requires to deliver nucleic acids, or other macromolecules into cells, which may pose difficult tasks to pharmaceutical companies. To overcome this technological limitation, a wide variety of vectors have been developed in the past decades and have proven to be successful in delivering various therapeutics. Cell-penetrating peptides (CPP) have been one of the technologies widely studied and have been increasingly used to transport small RNA/DNA, plasmids, antibodies, and nanoparticles into cells. Despite the already proved huge potential that these peptide-based approaches may suggest, few advances have been put to pharmacological or clinical use. This review will describe the origin, development, and usage of CPP to deliver therapeutic agents into cells, with special emphasis on their current application to gene-therapies. Specifically, we will describe the current trials being conducted to treat cancer, gene disorders, and autoimmune diseases using CPP-based therapies. © 2014 IUBMB Life, 66(3):182-194, 2014.

Intracellular nucleic acid delivery by the supercharged dengue virus capsid protein

Supercharged proteins are a recently identified class of proteins that have the ability to efficiently deliver functional macromolecules into mammalian cells. They were first developed as bioengineering products, but were later found in the human proteome. In this work, we show that this class of proteins with unusually high net positive charge is frequently found among viral structural proteins, more specifically among capsid proteins. In particular, the capsid proteins of viruses from the Flaviviridae family have all a very high net charge to molecular weight ratio (> +1.07/kDa), thus qualifying as supercharged proteins. This ubiquity raises the hypothesis that supercharged viral capsid proteins may have biological roles that arise from an intrinsic ability to penetrate cells. Dengue virus capsid protein was selected for a detailed experimental analysis. We showed that this protein is able to deliver functional nucleic acids into mammalian cells. The same result was obtained with two isolated domains of this protein, one of them being able to translocate lipid bilayers independently of endocytic routes. Nucleic acids such as siRNA and plasmids were delivered fully functional into cells. The results raise the possibility that the ability to penetrate cells is part of the native biological functions of some viral capsid proteins.

Quantifying molecular partition of cell-penetrating peptide-cargo supramolecular complexes into lipid membranes: optimizing peptide-based drug delivery systems

One of the major challenges in the drug development process is biodistribution across epithelia and intracellular drug targeting. Cellular membrane heterogeneity is one of the major drawbacks in developing efficient and sustainable drug delivery systems, which brings the need to study their interaction with lipids in order to unravel their mechanisms of action and improve their delivery capacities. Cell penetrating peptides (CPPs) are able to translocate almost any cell membrane carrying cargo molecules. However, different CPP use different entry mechanisms, which are often concentration-dependent and cargo-dependent. Being able to quantify the lipid affinity of CPP is of obvious importance and can be achieved by studying the partition extent of CPP into lipid bilayers. The partition constant (Kp) reflects the lipid-water partition extent. However, all currently available methodologies are only suitable to determine the partition of single molecules into lipid membranes or entities, being unsuitable to determine the partition of bimolecular or higher order supramolecular complexes. We derived and tested a mathematical model to determine the Kp of supramolecular CPP-cargo complexes from fluorescence spectroscopy data, using DNA oligomers as a model cargo. As a proof-of-concept example, the partition extent of two new membrane active peptides derived from dengue virus capsid protein (DENV C protein) with potential CPP properties, in both scenarios (free peptide and complexed with a molecular cargo), were tested. We were able to identify the lipid affinity of these CPP:DNA complexes, thus gaining valuable insights into better CPP formulations.

Anti-proliferative effect of the essential oil ofCymbopogon citratus(DC) Stapf (lemongrass) on intracellular amastigotes, bloodstream trypomastigotes and culture epimastigotes ofTrypanosoma cruzi(Protozoa: Kinetoplastida)

This study analyses the anti-proliferative effect of lemongrass essential oil and its main constituent (citral) on all 3 evolutive forms ofTrypanosoma cruzi. Steam distillation was used to obtain lemongrass essential oil, with chemical composition determined by gas chromatography (GC) and GC coupled to mass spectrometry (GC-MS). The IC50/24 h (concentration that reduced the parasite population by 50%) of the oil and of citral uponT. cruziwas determined by cell counting in a Neubauer chamber, while morphological alterations were visualized by scanning and transmission electron microscopy. Treatment with the essential oil resulted in epimastigote growth inhibition with IC50=126·5 μg/ml, while the IC50for trypomastigote lysis was 15·5 μg/ml. The IC50/48 h for the Association Index (% macrophage infection×number of amastigotes per cell) was 5·1 μg/ml, with a strong inhibition of intracellular amastigote proliferation. Ultrastructural analysis demonstrated cytoplasmic and nuclear extraction, while the plasma membrane remained morphologically preserved. Our data show that lemongrass essential oil is effective againstT. cruzitrypomastigotes and amastigotes, and that its main component, citral, is responsible for the trypanocidal activity. These results indicate that essential oils can be promising anti-parasitic agents, opening perspectives to the discovery of more effective drugs of vegetal origin for treatment of parasitic diseases. However, additional cytotoxicity experiments on different cell lines and tests in aT. cruzi-mouse model are needed to support these data.

[The Child Oral Care Program (PADI) of Navarra and the Basque Country: achievements and new goals]

This paper briefly analyses the results of the Infant Dental Care Program (PADI) of the Basque Country (1990) and Navarra (1991), aimed at children aged from 6 and 15 years. At the age 12, the lack of caries rose from 31% in 1988 to 57% in 1998 in the Basque Country, while it was 58% in Navarra (1997); the number of caries fell in Navarra by some 64% and by some 54% in the Basque Country, and the index of restoration was 81% in Navarra and 73% in the Basque Country (it was 17% in 1988). Emphasis is placed on the importance of a good evaluation of these programs and the opportunities that are opened up by the comparative analysis between Spanish autonomous communities for analysing the contribution of factors that are different, and for evaluating the impact of the programs on social inequalities in health. The results of the PADI exceed the initial aims of the Health Plans of Navarra (1991) and of the Basque Country (1990), and endorse the adoption of these programs by the Spanish autonomous communities. The development of these programs raises new objectives in dental health policy in Navarra and the Basque Country and, above all, makes it necessary to reflect on the need for Spain to include public dental health in its health policy and for the National Health System as a whole to include dental services within its services

[Determination of insulin, leptin and neuropeptide y by radioimmunoanalysis in patients with morbid obesity and anorexia nervosa after therapeutic intervention]

The present study was conducted in order to analyze the relationship existing between leptin, insulin and neuropeptide Y (NPY) levels in massive weight loss and weight recovery. Twenty-three patients with severe obesity, 23 patients with anorexia nervosa and 28 healthy control subjects were studied. Patients with severe obesity underwent a vertical banded gastroplasty followed by an 800 kcal/day diet during 16 weeks, with evaluation taking place before (Body mass index, BMI, 52,1 8 Kg/m2) and after the drastic weight loss (BMI 39,2 6,2 Kg/m2). Patients with anorexia nervosa were treated with nutritional therapy exclusively during 16 weeks, and they were evaluated in the low weight situation (BMI 15,3 1,7 Kg/m2) and after weight recovery (BMI 18,9 2,8 Kg/m2). Normal subjects had a normal BMI from 20 to 27 (average 21,8 2 Kg/m2). BMI, percentage of body fat, and serum levels of leptin, insulin, and NPY, were determined in each patient and normal subjects. In severe obese patients serum leptin and insulin decreased significantly after drastic weight reduction (leptin: from 48,8 19,2 to 24,3 9,8 ng/ml; insulin: from 26,2 10,8 to 18 6 U/ml). In patients with anorexia nervosa serum leptin mean levels were significantly higher after weight recovery (3,7 1,9 vs 9,2 5,1 ng/ml). In subjects with morbid obesity NPY levels decreased after weight loss below those of control group (43,5 16,1 vs 57,3 12,8 pmol/l). On the other hand, patients with anorexia nervosa had NPY levels superior to those of control group. In subjects with anorexia, NPY levels decreased after weight recovery (69,1 16,7 a 59,1 20,3 pmol/l). In the whole population, Leptin and NPY plasma levels were correlated with body fat percentage. Leptin was positively correlated with BMI and body fat percentage in obese and anorectic subjects after weight loss or recovery, respectively. NPY was inversely correlated with body fat percentage in controls and obese subjects before treatment. These data reveal that the concentration of serum leptin and NPY correlates significantly with the total adiposity in subjects with a wide weight range and caloric intake. Leptin plasma levels are proportional to fat stores in patients with severe obesity and anorexia nervosa after drastic weight loss or recovery, respectively. NPY serum levels are negatively correlated with de total body fat in normal weight subjects and obese patients in their initial weight.

[Plasma levels of insulin and leptin in patients with morbid obesity and anorexia nervosa after weight loss or gain, respectively]

The present study was conducted in order to analyze the relationship existing between leptin and insulin levels in massive weight loss and weight recovery. Thirteen patients with severe obesity, 14 patients with anorexia nervosa and 13 healthy control subjects were studied. The patients with severe obesity underwent a vertical banded gastroplasty followed by an 800 kcal/day diet for 12 weeks. They were evaluated prior to (body mass index [BMI] 51.2 +/- 8.8 Kg/m2) and after drastic weight loss (BMI 40.6 +/- 6.7 Kg/m2). Patients with anorexia nervosa were treated exclusively with nutritional therapy during 12 weeks, and they were evaluated at their lowest weight status (BMI 16.2 +/- 2.2 Kg/m2) and after weight recovery (BMI 17.9 +/- 2.3 Kg/m2). The BMI of the normal subjects was in the normal range of 20 to 27 Kg/m2 (average 22.8 +/- 2.6 Kg/m2). BMI, percentage of body fat, waist circumference, and serum levels of leptin, insulin, and C-peptide were determined in each patient and normal subject. In severely obese patients, serum leptin and insulin decreased significantly after drastic weight reduction (leptin: from 51.8 +/- 22.3 to 23.7 +/- 10.2 ng/ml; insulin: from 27.1 +/- 13.3 to 17.2 +/- 7.2 mU/ml). In patients with anorexia nervosa, the mean serum leptin levels were significantly higher after weight recovery (5.5 +/- 3.2 vs 7.6 +/- 6 ng/ml). Serum leptin in the severe obesity group correlated positively with BMI, percentage body fat and waist circumference before and after weight loss. In those patients suffering from anorexia nervosa, serum leptin correlated positively with the BMI, percentage of body fat, and waist circumference in the low weight state and after weight recovery. In addition, their serum insulin correlated with BMI and waist circumference after weight recovery. These data reveal that serum leptin concentration correlates significantly with the BMI and body fat content 1) in subjects with a range of weight and caloric intake, 2) in obese patients after drastic weight loss; 3) in anorexic patients after weight gain; and that hyper- or normoinsulinemia do not seem to have any influence on the leptin changes caused by weight loss or gain.

Clinical parameters (body mass index and age) are the best predictors for the need of insulin therapy during the first 18 months of diabetes mellitus in young adult patients

To address the question whether there are simple clinical predictors of need for insulin in the first 18 months of treatment of diabetes presenting in young adult subjects, a prospective study of 24 patients with diabetes mellitus (age: 18-40 years) was designed. At diagnosis of diabetes, age, sex, body mass index (BMI), glycemia, ketonuria, C-peptide, insulin autoantibodies, islet cell antibodies and glutamic acid decarboxylase antibodies were recorded before starting any treatment. At the end of the follow-up (18 +/- 4 months), they were divided into two groups according to their need for insulin therapy: group 1 (n=15; 62%), who needed insulin therapy, and group 2 (n=9; 38%), who did not. Each marker was related to actual need for therapy necessity. Multivariate analysis showed that BMI and age were the variables with greatest predictive value regarding need for insulin. These data reveal that the need for insulin therapy in young adult diabetic patients may be supported by the clinical criteria of age and BMI, which are both easily and quickly determined.

European School of Oncology Advisory report to the European Commission for the "Europe Against Cancer Programme" European Code Against Cancer

A European School of Oncology Advisory Group has reviewed the European Code Against Cancer after its initial use over a 6-year period. With minor modifications, the original ten recommendations were found to be adequate, although it was agreed that an Annex was necessary to explain the scientific evidence supporting each point, and is presented herewith. Tobacco smoking clearly remains the most important cause of cancer, and now it can be quantified better than ever before. It is also clear that it is never too late to stop smoking: stopping even in middle age, prior to the onset of serious illness has a beneficial effect on life expectancy. Alcohol drinking is an important cause of cancer, and yet modest consumption levels protect against cardiovascular disease mortality. The optimal strategy seems to be a consumption not exceeding 2-3 drinks per day, although this limit may be lower for women. Increased consumption of fruits and vegetables, reduction in consumption of fatty foods, reduction of obesity and increased physical activity can all be recommended to reduce cancer risk. Exposure to excessive sunlight remains a problem which should be limited. Control of occupational cancer is a three-way partnership: legislation identifies and limits exposure to known carcinogens, employers enact the legislation and workers should respect the measures introduced. There are a number of signs and symptoms which may lead to cancer being diagnosed earlier, and patients with these should be referred to a doctor. For women, participation in organised programmes of cervical cancer and breast cancer (after 50 years of age) should lead to a reduction in mortality from these forms of cancer. The key element is organised programmes, where quality control and quality assurance are in force. These revised recommendations are the result of an agreement following advice, review and dialogue with cancer experts throughout Europe. They were approved by the European Community Cancer Experts at their meeting in Bonn on 28-29 November 1994. Their implementation by the European population should greatly reduce cancer incidence and mortality.

Purification of thymus mRNA coding for a 16,000-dalton polypeptide containing the thymosin alpha 1 sequence

A mRNA fraction purified by preparative polyacrylamide disc gel electrophoresis from calf thymus polysomes codes for a polypeptide(s) having a mass of 16,000-17,000 daltons. This polypeptide contains amino acid sequences corresponding to residues 11-18 and 19-25 of thymosin alpha 1. The yield of the octapeptide indicates that the 16,000-dalton peptide is the major product formed in the cell-free synthesis system containing the purified mRNA.