Computing by Floating Strings

We propose a biologically inspired system which computes on double structures of mobile strings by means of rewriting rules that have a biotechnological implementation, by resembling DNA computations. Its computational universality may be straight deduced from a few formal language theoretical results of one of the authors. Such a DNA-like computational device is naturally described by a membrane system which concludes the paper.     

Effects of antihypertensive treatment on vasopressin secretion and on its osmoregulation in moderate hypertension

BACKGROUND: Changes in plasma osmolality and arterial pressure can affect the secretion of vasopressin (AVP). OBJECTIVE: To investigate the effect of a drug-induced lowering of the arterial pressure on the plasma concentration of AVP and on its osmoregulation in moderately severe uncomplicated hypertensives. DESIGN AND METHODS: A group of 33 moderate uncomplicated and untreated essential hypertensives of both sexes (mean age 48 +/- 1 years, average arterial pressure 171 +/- 3/108 +/- 2 mmHg) was studied. We measured AVP and other plasma and urine variables in 21 of them before and after administration of a hypertonic NaCl solution (100 mmol NaCl in 50 ml). Antihypertensive treatment with a single drug or, if necessary, with a combination of drugs was initiated for eight of these subjects and hypertonic saline administration was repeated after 1 month of treatment. The hypertonic stimulus was administered to the other 12 subjects after acute lowering of the arterial pressure by continuous intravenous infusion either of 0.3 mg clonidine in 100 ml (n = 6) or of 50 mg sodium nitroprusside in 250 ml (n = 6). RESULTS: Administration of hypertonic saline to untreated hypertensives increased their AVP level from 1.6 +/- 0.28 to 5.4 +/- 0.7 pg/ml (n = 21, P < 0.01). Their mean arterial pressure was lowered after pharmacological treatment for 1 month (n = 8) from 125 +/- 2 to 101 +/- 2 mmHg; their baseline AVP level remained unchanged (1.2 +/- 0.21 versus 0.9 +/- 0.25 pg/ml); after hypertonic saline had been administered to hypertensives with lowered arterial pressures, their AVP level increased to 6.0 +/- 1.03 pg/ml (P < 0.01). The AVP level in subjects whose MAP had been lowered acutely by administration of clonidine (n = 6) or of sodium nitroprusside (n = 6; on the average, from 132 +/- 3 to 110 +/- 4 mmHg) increased concurrently from 1.6 +/- 0.63 to 3.4 +/- 0.7 pg/ml (P < 0.05); after administration of the hypertonic saline the AVP level increased to 10.8 +/- 2.22 pg/ml (P < 0.01). This stimulated value was significantly (P < 0.01) higher than that observed after hypertonic saline had been administered to untreated hypertensives (5.4 +/- 0.7 pg/ml). CONCLUSIONS: Acute lowering of the arterial pressure in moderate essential hypertension appears to facilitate the secretion and osmoregulation of AVP. On the other hand, during prolonged antihypertensive treatment, baroreflex regulation of the secretion of AVP appears to be set at a lower operating point, thus exerting the same influence on the release of AVP as it did before antihypertensive treatment.     

Neurofilament proteins are synthesized in nerve endings from squid brain

It is generally believed that the proteins of the nerve endings are synthesized on perikaryal polysomes and are eventually delivered to the presynaptic domain by axoplasmic flow. At variance with this view, we have reported previously that a synaptosomal fraction from squid brain actively synthesizes proteins whose electrophoretic profile differs substantially from that of the proteins made in nerve cell bodies, axons, or glial cells, i.e., by the possible contaminants of the synaptosomal fraction. Using western analyses and immunoabsorption methods, we report now that (a) the translation products of the squid synaptosomal fraction include neurofilament (NF) proteins and (b) the electrophoretic pattern of the synaptosomal newly synthesized NF proteins is drastically different from that of the NF proteins synthesized by nerve cell bodies. The latter results exclude the possibility that NF proteins synthesized by the synaptosomal fraction originate in fragments of nerve cell bodies possibly contaminating the synaptosomal fraction. They rather indicate that in squid brain, nerve terminals synthesize NF proteins.     

Geographical discrimination of honeys through antioxidant capacity,mineral content and colour

The assessment of geographical origin of honey is economically important for producers and consumers as every region may present particular quality characteristics. In this study, honeys from the seven different regions of Buenos Aires province (Argentina) were characterised by their antioxidant capacity (DPPH, FRAP), total phenolic content (TPC), mineral composition, colour and ash. Honeys showed significant differences among their antioxidant capacity (DPPH), ash, colour and mineral content (P ≤ 0.05). Besides, a good antioxidant activity and low amounts of Cu and Zn (<1.0–1.5 and 0.7–1.8 mg kg^?1, respectively) were found in the samples. Significant Pearson's correlations (P ≤ 0.05) among the different parameters were found. Moreover, the linear discriminant analysis allowed the classification of honeys in their original groups with a prediction success of 98%. The present results suggest that honeys could be correctly classified by their geographical origin through their TPC, colour, ash and mineral concentrations.     

A Novel GUCA1A Variant Associated with Cone Dystrophy Alters cGMP Signaling in Photoreceptors by Strongly Interacting with and Hyperactivating Retinal Guanylate Cyclase

Guanylate cyclase-activating protein 1 (GCAP1), encoded by the GUCA1A gene, is a neuronal calcium sensor protein involved in shaping the photoresponse kinetics in cones and rods. GCAP1 accelerates or slows the cGMP synthesis operated by retinal guanylate cyclase (GC) based on the light-dependent levels of intracellular Ca²⁺, thereby ensuring a timely regulation of the phototransduction cascade. We found a novel variant of GUCA1A in a patient affected by autosomal dominant cone dystrophy (adCOD), leading to the Asn104His (N104H) amino acid substitution at the protein level. While biochemical analysis of the recombinant protein showed impaired Ca²⁺ sensitivity of the variant, structural properties investigated by circular dichroism and limited proteolysis excluded major structural rearrangements induced by the mutation. Analytical gel filtration profiles and dynamic light scattering were compatible with a dimeric protein both in the presence of Mg²⁺ alone and Mg²⁺ and Ca²⁺. Enzymatic assays showed that N104H-GCAP1 strongly interacts with the GC, with an affinity that doubles that of the WT. The doubled IC₅₀ value of the novel variant (520 nM for N104H vs. 260 nM for the WT) is compatible with a constitutive activity of GC at physiological levels of Ca²⁺. The structural region at the interface with the GC may acquire enhanced flexibility under high Ca²⁺ conditions, as suggested by 2 μs molecular dynamics simulations. The altered interaction with GC would cause hyper-activity of the enzyme at both low and high Ca²⁺ levels, which would ultimately lead to toxic accumulation of cGMP and Ca²⁺ in the photoreceptor outer segment, thus triggering cell death.     

Metabolic P Systems： A Discrete Model for Biological Dynamics

A recent methodology to model biochem- ical systems is here presented. It is based on a concep- tual framework rooted in membrane computing and de- veloped with concepts typical of discrete dynamical sys- tems. According to our approach, from data observed at suitable macroscopic temporal scales, one can deduce, by means of algebraic and algorithmic procedures, a dis- crete model （called Metabolic P system） which accounts for the experimental data, and opens the possibility to under- stand the systemic logic of the investigated phenomenon. The procedures of such a method have been implemented within a computational platform, a Java software called MetaPlab, processing data and simulating behaviors of metabolic models. In the paper, we briefly describe the theory underlying the modeling of biochemical systems by Metabolic P systems, along with its development stages and the related extensive literature.     

Activity of Brassica oleracea leaf juice on foodborne pathogenic bacteria

Many vegetables of the Cruciferae family have been found to possess antimicrobial properties against several microorganisms of clinical importance. In this study, we reported the antibacterial effect of Brassica oleracea juice on several food-borne pathogens. The juice was found to be effective in inhibiting the growth of Salmonella Enteritidis, verotoxigenic Escherichia coli O157:H7, E. coli HB producing thermolabile toxin, nontoxigenic E. coli, and Listeria monocytogenes, but not Enterococcus faecalis. All cauliflower cultivars tested suppressed bacterial growth in a dose-dependent manner after 5 h of treatments, and the reduction in the number of viable cells ranged from 1 log with a 10% juice concentration to more than 3 log with a 20% juice concentration. The foodborne bacteria tested were also markedly reduced by isothiocyanates, natural components abundant in the genus Brassica, indicating that glucosinolate-derived isothiocyanates can play a major role in the antimicrobial activity of cauliflower. The antimicrobial effect of juice was reduced in presence of cysteine, suggesting that one mechanism of action of the juice involves blocking bacterial sulfhydryl groups.     

Algorithmic applications of XPCR

An emerging trend in DNA computing consists of the algorithmic analysis of new molecular biology technologies, and in general of more effective tools to tackle computational biology problems. An algorithmic understanding of the interaction between DNA molecules becomes the focus of some research which was initially addressed to solve mathematical problems by processing data within biomolecules. In this paper a novel mechanism of DNA recombination is discussed, that turned out to be a good implementation key to develop new procedures for DNA manipulation (Franco et al., DNA extraction by cross pairing PCR, 2005; Franco et al., DNA recombination by XPCR, 2006; Manca and Franco, Math Biosci 211:282–298, 2008). It is called XPCR as it is a variant of the polymerase chain reaction (PCR), which was a revolution in molecular biology as a technique for cyclic amplification of DNA segments. A few DNA algorithms are proposed, that were experimentally proven in different contexts, such as, mutagenesis (Franco, Biomolecular computing—combinatorial algorithms and laboratory experiments, 2006), multiple concatenation, gene driven DNA extraction (Franco et al., DNA extraction by cross pairing PCR, 2005), and generation of DNA libraries (Franco et al., DNA recombination by XPCR, 2006), and some related ongoing work is outlined.     

Bioactivities of Pseudocereal Fractionated Seed Proteins and Derived Peptides Relevant for Maintaining Human Well-Being

Food proteins and peptides are able to exert a variety of well-known bioactivities, some of which are related to well-being and disease prevention in humans and animals. Currently, an active trend in research focuses on chronic inflammation and oxidative stress, delineating their major pathogenetic role in age-related diseases and in some forms of cancer. The present study aims to investigate the potential effects of pseudocereal proteins and their derived peptides on chronic inflammation and oxidative stress. After purification and attribution to protein classes according to classic Osborne’s classification, the immune-modulating, antioxidant, and trypsin inhibitor activities of proteins from quinoa (Chenopodium quinoa Willd.), amaranth (Amaranthus retroflexus L.), and buckwheat (Fagopyrum esculentum Moench) seeds have been assessed in vitro. The peptides generated by simulated gastro-intestinal digestion of each fraction have been also investigated for the selected bioactivities. None of the proteins or peptides elicited inflammation in Caco-2 cells; furthermore, all protein fractions showed different degrees of protection of cells from IL-1β-induced inflammation. Immune-modulating and antioxidant activities were, in general, higher for the albumin fraction. Overall, seed proteins can express these bioactivities mainly after hydrolysis. On the contrary, higher trypsin inhibitor activity was expressed by globulins in their intact form. These findings lay the foundations for the exploitation of these pseudocereal seeds as source of anti-inflammatory molecules.     

Characterization of transition sleep episodes in baseline EEG recordings of adult rats

By scoring 5-s EEG epochs and calculating spectral power of consecutive EEG segments as short as 1-s, transition sleep (TS) episodes were identified in baseline recordings of adult rats. TS episodes were characterized by the abrupt appearance of theta and alpha waves within an ongoing period of slow-wave sleep (SS). They were followed by paradoxical sleep (PS) or, somewhat more frequently, by a period of wakefulness (W) that often led to an additional SS. Statistical values of the main variables of TS-->(W) and TS-->(PS) episodes are presented, together with comparable data concerning previous SS and following W or PS episodes. On the whole, TS episodes were more numerous than PS episodes, and less numerous than SS episodes. Their average duration was considerably shorter. As a consequence of the identification of TS and of brief W or PS epochs intervening within SS, the number of SS episodes was estimated to be considerably higher than previously assessed, and their average duration considerably shorter.