Fed‐batch production of tetanus toxin by Clostridium tetani

This study deals with the effects of the initial nitrogen source (NZ Case TT) level and the protocol of glucose addition during the fed‐batch production of tetanus toxin by Clostridium tetani. An increase in the initial concentration of NZ Case TT (NZ₀) accelerated cell growth, increased the consumption of the nitrogen source as well as the final yield of tetanus toxin, which achieved the highest values (50–60 L_f/mL) for NZ₀ ≥ 50 g/L. The addition of glucose at fixed times (16, 56, and 88 h) ensured a toxin yield (～60 L_f/mL) about 33% higher than those of fed‐batch runs with addition at fixed concentration (～45 L_f/mL) and about 300% higher than those obtained in reference batch runs nowadays used at industrial scale. The results of this work promise to substantially improve the present production of tetanus toxin and may be adopted for human vaccine production after detoxification and purification. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010     

Escherichia coli Ribosomal Protein S1 Unfolds Structured mRNAs Onto the Ribosome for Active Translation Initiation

Regulation of translation initiation is well appropriate to adapt cell growth in response to stress and environmental changes. Many bacterial mRNAs adopt structures in their 5′ untranslated regions that modulate the accessibility of the 30S ribosomal subunit. Structured mRNAs interact with the 30S in a two-step process where the docking of a folded mRNA precedes an accommodation step. Here, we used a combination of experimental approaches in vitro (kinetic of mRNA unfolding and binding experiments to analyze mRNA–protein or mRNA–ribosome complexes, toeprinting assays to follow the formation of ribosomal initiation complexes) and in vivo (genetic) to monitor the action of ribosomal protein S1 on the initiation of structured and regulated mRNAs. We demonstrate that r-protein S1 endows the 30S with an RNA chaperone activity that is essential for the docking and the unfolding of structured mRNAs, and for the correct positioning of the initiation codon inside the decoding channel. The first three OB-fold domains of S1 retain all its activities (mRNA and 30S binding, RNA melting activity) on the 30S subunit. S1 is not required for all mRNAs and acts differently on mRNAs according to the signals present at their 5′ ends. This work shows that S1 confers to the ribosome dynamic properties to initiate translation of a large set of mRNAs with diverse structural features.     

Phase Advance Is an Actimetric Correlate of Antidepressant Response to Sleep Deprivation and Light Therapy in Bipolar Depression

The combination of total sleep deprivation (TSD) and light therapy (LT) in bipolar depression causes rapid antidepressant effects, and its mechanism of action has been hypothesized to involve the enhancement of all of the monoaminergic systems targeted by antidepressant drugs (serotonin, dopamine, norepinephrine). It is still unknown if the clinical effects are paralleled by changes in biological rhythms. In a before/after design of a study of biological correlates of response, 39 inpatients affected by Type I Bipolar Disorder whose current depressive episode was without psychotic features were treated for one week with repeated TSD combined with morning LT. Wrist actigraphy was recorded throughout the study. Two‐thirds of the patients responded to treatment (50% reduction in Hamilton Depression score). Responders showed an increase in daytime activity, phase‐advance of the activity‐rest rhythm of 57 min compared to the pre‐treatment baseline, and reduced nighttime sleep. Non‐responders did not show significant changes in the parameters of their activity‐rest rhythm. Phase advance of the activity‐rest rhythm is an actimetric correlate of the antidepressant response to TSD and LT in bipolar depression. Results are consistent with the known effects of sleep‐wake manipulations and neurotransmitter function on the suprachiasmatic nucleus.     

Primi Dati Sulle Alghe Della Scogliera « I Travi » di Portonovo (Ancona)

Abstract

First data on the seaweeds of the reef « I Travi » of Portonovo (Ancona). — The reef « I Travi » is formed by a series of nearly vertical rock strata which from Mount « I Corvi » dip into the sea with a general direction WNW-ESE. The rock face looking towards the open sea (that is roughly to the North) is exposed to the action of the waves. The sea is particulary rough when the wind blows from the North (« Bora »), and the East (« Levante »).

The temperature of the water throughout the year varies from 9.5[ddot] C in February to 27 [ddot]C in September, that is over a range of 17.5 [ddot]C. In June the salinity of the water was of 33.6%, and the pH had a value of 8.1. Ascending and descending currents and water movements seem to mix efficiently the upper and lower waters.

The seaweed population of the rock face varies longitudinally. In the Wetsern part Acetabularia is dominant; there is a central part with prevalence of Cystoseira, and an eastern part with prevalence of Ceramium and Cladophora. Vertically one can distinguish: a Littoral Zone of 40–45 cm (maximum amplitude of the tides) with Cladophora, Enteromorpha, and other Chlorophyceae; an Infralittoral Zone with predominance of Cystoseira, Gracilaria, and, lower down of various Rhodophyceae. The Eulittoral Zone is missing.     

Pedigree Reconstruction of the Italian Grapevine Aglianico (Vitis vinifera L.) from Campania

A total of 41 accessions of Aglianico belonging to three different biotypes (Taburno, Taurasi, and Vulture) and 9 accessions of Sirica grapes were sampled from diverse areas of Campania (Italy). All accessions were first genotyped using 21 microsatellite markers (SSR) to evaluate possible homonymies, synonymies, and the genetic structure of each group. A larger dataset was then constructed adding Italian and International cultivars. On the basis of results obtained analyzing the first dataset, further investigations were carried out enlarging the number of investigated loci (up to 43). The addition of 22 SSRs was useful in the definition of likely genetic relationships linking Aglianico biotypes, Sirica and Syrah. According to their SSR allelic profiles, the monophyletic origin of the three Aglianico biotypes was confirmed. Among Aglianico Taburno accessions, eight samples (called Aglianico like-to-type) performed a different SSR allelic profile from Aglianico true-to-type. Sirica and Syrah proved to be synonyms. This work allowed to determine the genetic relationship between Aglianico and the cultivars supposed to be related. The parentage analysis was investigated. The most likely pedigree has been reconstructed; revealing a second-degree relationship between the worldwide cultivated Syrah from the Rhone Valley and Aglianico. Aglianico like-to-type appeared related to Aglianico in a parent-offspring fashion.     

Lycorine induces cell death in the amitochondriate parasite, Trichomonas vaginalis, via an alternative non-apoptotic death pathway

In this study, the mechanism of action of the pro-apoptotic alkaloid lycorine on an amitochondriate cell, the parasite Trichomonas vaginalis, was investigated. The cytotoxicity of lycorine against T. vaginalis was studied from 2.5 to 1000 μM and several important ultrastructural alterations were observed by electron microscopy. Lycorine arrested the T. vaginalis cell cycle, although no hallmarks of apoptosis, such as apoptotic bodies, were observed. Consequently, the underlying mechanism of action fails to completely fulfill the criteria for apoptosis. However, some similarities to paraptotic cell death were observed.     

Early and transient release of leukocyte pentraxin 3 during acute myocardial infarction

Pentraxin 3 (PTX3) plays cardioprotective and anti-atherogenic roles in murine models. PTX3 blood levels raise during early acute myocardial infarction (AMI). Neutrophils from healthy subjects physiologically contain PTX3 in secondary (also called specific) granules. In this study, we report that circulating neutrophils release preformed PTX3 in the early phase of AMI (within 6 h from the onset of clinical symptoms). Depletion of intracellular PTX3 correlates with increased plasma levels and with platelet-neutrophil heterotypic aggregates. Neutrophil PTX3 returns to normal values 48 h after the onset of symptoms; concentration does not vary in matched healthy controls or in patients with chronic stable angina. In vitro, recognition of activated P-selectin(+) platelets causes the formation of neutrophil-platelet heteroaggregates and the release of neutrophil PTX3. Purified or membrane-bound P-selectin triggers PTX3 release from resting neutrophils. Released PTX3 binds to activated platelets in vitro. Moreover, PTX3 binds to a substantial fraction of platelets from patients in the circulating blood. PTX3-bound activated platelets have a reduced ability to 1) form heterotypic aggregates with neutrophils and monocytes; 2) activate neutrophils, as evaluated assessing the upregulation of leukocyte β(2) integrins; 3) aggregate with other platelets; and 4) bind to fibrinogen. Our results suggest that neutrophils early release prestored PTX3 in patients undergoing AMI. PTX3 binds to activated circulating platelets and dampens their proinflammatory and prothrombotic action, thus possibly contributing to its cardioprotective effects.     

Fed-Batch Cultivation of Arthrospira platensis Using Carbon Dioxide from Alcoholic Fermentation and Urea as Carbon and Nitrogen Sources

To reduce CO₂ emissions from alcoholic fermentation, Arthrospira platensis was cultivated in tubular photobioreactor using either urea or nitrate as nitrogen sources at different light intensities (60 μmol m^?2 s^?1?≤?I?≤?240 μmol m^?2 s^?1). The type of carbon source (pure CO₂ or CO₂ from fermentation) did not show any appreciable influence on the main cultivation parameters, whereas substitution of nitrate for urea increased the nitrogen-to-cell conversion factor (Y _X/N ), and the maximum cell concentration (X _m ) and productivity (P _X ) increased with I. As a result, the best performance using gaseous emissions from alcoholic fermentation (X _m ?=?2,960?±?35 g m^?3, P _X ?=?425?±?5.9 g m^?3 day^?1 and Y _X/N ?=?15?±?0.2 g g^?1) was obtained at I?=?120 μmol m^?2 s^?1 using urea as nitrogen source. The results obtained in this work demonstrate that the combined use of effluents rich in urea and carbon dioxide could be exploited in large-scale cyanobacteria cultivations to reduce not only the production costs of these photosynthetic microorganisms but also the environmental impact associated to the release of greenhouse emissions.     

Production of Chlorella vulgaris as a source of essential fatty acids in a tubular photobioreactor continuously fed with air enriched with CO2 at different concentrations

To reduce CO₂ emissions and simultaneously produce biomass rich in essential fatty acids, Chlorella vulgaris CCAP 211 was continuously grown in a tubular photobioreactor using air alone or air enriched with CO₂ as the sole carbon source. While on one hand, nitrogen‐limited conditions strongly affected biomass growth, conversely, they almost doubled its lipid fraction. Under these conditions using air enriched with 0, 2, 4, 8, and 16% (v/v) CO₂, the maximum biomass concentration was 1.4, 5.8, 6.6, 6.8, and 6.4 g_DB L^?1 on a dry basis, the CO₂ consumption rate 62, 380, 391, 433, and 430 L^?1 day^?1, and the lipid productivity 3.7, 23.7, 24.8, 29.5, and 24.4 mg L^?1 day^?1, respectively. C. vulgaris was able to grow effectively using CO₂‐enriched air, but its chlorophyll a (3.0–3.5 g 100g_DB^?1), chlorophyll b (2.6–3.0 g 100g_DB^?1), and lipid contents (10.7–12.0 g 100g_DB^?1) were not significantly influenced by the presence of CO₂ in the air. Most of the fatty acids in C. vulgaris biomass were of the saturated series, mainly myristic, palmitic, and stearic acids, but a portion of no less than 45% consisted of unsaturated fatty acids, and about 80% of these were high added‐value essential fatty acids belonging to the ω3 and ω6 series. These results highlight that C. vulgaris biomass could be of great importance for human health when used as food additive or for functional food production. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:916–922, 2014