Compaction properties of an intrinsically disordered protein: Sic1 and its kinase-inhibitor domain

IDPs in their unbound state can transiently acquire secondary and tertiary structure. Describing such intrinsic structure is important to understand the transition between free and bound state, leading to supramolecular complexes with physiological interactors. IDP structure is highly dynamic and, therefore, difficult to study by conventional techniques. This work focuses on conformational analysis of the KID fragment of the Sic1 protein, an IDP with a key regulatory role in the cell-cycle of Saccharomyces cerevisiae. FT-IR spectroscopy, ESI-MS, and IM measurements are used to capture dynamic and short-lived conformational states, probing both secondary and tertiary protein structure. The results indicate that the isolated Sic1 KID retains dynamic helical structure and populates collapsed states of different compactness. A metastable, highly compact species is detected. Comparison between the fragment and the full-length protein suggests that chain length is crucial to the stabilization of compact states of this IDP. The two proteins are compared by a length-independent compaction index.     

The Golgi apparatus: an organelle with multiple complex functions

Remarkable advances have been made during the last few decades in defining the organizational principles of the secretory pathway. The Golgi complex in particular has attracted special attention due to its central position in the pathway, as well as for its fascinating and complex structure. Analytical studies of this organelle have produced significant advances in our understanding of its function, although some aspects still seem to elude our comprehension. In more recent years a level of complexity surrounding this organelle has emerged with the discovery that the Golgi complex is involved in cellular processes other than the 'classical' trafficking and biosynthetic pathways. The resulting picture is that the Golgi complex can be considered as a cellular headquarters where cargo sorting/processing, basic metabolism, signalling and cell-fate decisional processes converge.     

Chemo-orientation responses in hymenopteran parasitoids induced by substrate-borne semiochemicals

Hymenopteran parasitoids can utilize substrate-borne semiochemicals released by conspecifics or by their hosts, increasing the likelihood of successful mating and host location. According to the literature, two substrate-borne chemo-orientation patterns can occur: (1) biased random searching, a non-directional reaction toward the chemicals (kinesis), and (2) trail-following searching, a directional response toward the source emitting the chemical compounds (taxis). These two different strategies can be adopted by parasitoids to locate hosts and mates. In host location, random searching is induced by allelochemicals indirectly associated with the host, whereas trail-following behavior is induced by allelochemicals directly emitted by the target organism. In mate finding, sex pheromones emitted by conspecifics can induce either the random searching or the trail-following behavior, although the spatial distribution of virgin conspecifics could be an important factor driving the evolution of substrate-borne chemo-orientation patterns. The chemical nature of substrate-borne semiochemicals has not yet been fully elucidated. Most studies have shown that crude extracts are biologically active for eliciting parasitoid arrestment response, but few studies have clearly characterized their chemical nature. However, experimental evidence indicates that cuticular lipids located in the external layer of insects’ bodies play a role in parasitoid–parasitoid and host–parasitoid communication. The ecological role of parasitoid chemo-orientation in host and mate location is discussed from a biological control perspective.     

Effects of Predictability of Load Magnitude on the Response of the Flexor Digitorum Superficialis to a Sudden Fingers Extension

Muscle reflexes, evoked by opposing a sudden joint displacement, may be modulated by several factors associated with the features of the mechanical perturbation. We investigated the variations of muscle reflex response in relation to the predictability of load magnitude during a reactive grasping task. Subjects were instructed to flex the fingers 2–5 very quickly after a stretching was exerted by a handle pulled by loads of 750 or 1250 g. Two blocks of trials, one for each load (predictable condition), and one block of trials with a randomized distribution of the loads (unpredictable condition) were performed. Kinematic data were collected by an electrogoniometer attached to the middle phalanx of the digit III while the electromyography of the Flexor Digitorum Superficialis muscle was recorded by surface electrodes. For each trial we measured the kinematics of the finger angular rotation, the latency of muscle response and the level of muscle activation recorded below 50 ms (short-latency reflex), between 50 and 100 ms (long-latency reflex) and between 100 and 140 ms (initial portion of voluntary response) from the movement onset. We found that the latency of the muscle response lengthened from predictable (35.5±1.3 ms for 750 g and 35.5±2.5 ms for 1250 g) to unpredictable condition (43.6±1.3 ms for 750 g and 40.9±2.1 ms for 1250 g) and the level of muscle activation increased with load magnitude. The parallel increasing of muscle activation and load magnitude occurred within the window of the long-latency reflex during the predictable condition, and later, at the earliest portion of the voluntary response, in the unpredictable condition. Therefore, these results indicate that when the amount of an upcoming perturbation is known in advance, the muscle response improves, shortening the latency and modulating the muscle activity in relation to the mechanical demand.     

Growth and biomass productivity of Scenedesmus vacuolatus on a twin layer system and a comparison with other types of cultivations

Scenedesmus is a genus of microalgae employed for several industrial uses. Industrial cultivations are performed in open ponds or in closed photobioreactors (PBRs). In the last years, a novel type of PBR based on immobilized microalgae has been developed termed porous substrate photobioreactors (PSBR) to achieve significant higher biomass density during cultivation in comparison to classical PBRs. This work presents a study of the growth of Scenedesmus vacuolatus in a Twin Layer System PSBR at different light intensities (600 μmol photons m⁻² s⁻¹ or 1000 μmol photons m⁻² s⁻¹), different types and concentrations of the nitrogen sources (nitrate or urea), and at two CO₂ levels in the gas phase (2% or 0.04% v/v). The microalgal growth was followed by monitoring the attached biomass density as dry weight, the specific growth rate and pigment accumulation. The highest productivity (29 g m⁻² d⁻¹) was observed at a light intensity of 600 μmol photons m⁻² s⁻¹ and 2% CO₂. The types and concentrations of nitrogen sources did not influence the biomass productivity. Instead, the higher light intensity of 1000 μmol photons m⁻² s⁻¹ and an ambient CO₂ concentration (0.04%) resulted in a significant decrease of productivity to 18 and 10–12 g m⁻² d⁻¹, respectively. When compared to the performance of similar cultivation systems (15–30 g m⁻² d⁻¹), these results indicate that the Twin Layer cultivation System is a competitive technique for intensified microalgal cultivation in terms of productivity and, at the same time, biomass density.

     

Evolución del microprolactinoma a largo plazo con tratamiento médico

IntroductionProlactinoma is the most frequent functioning pituitary adenoma. Most commonly occurs as microprolactinoma (less than 1 cm in size), which may be cured with medical therapy, but few long-term studies are available about optimal duration of treatment with dopamine agonists to ensure cure after drug discontinuation and its withdrawal without recurrence are do not report consistent results.ObjectiveTo establish criteria for cure of microprolactinoma with medical treatment and to analyze the potential predictors involved.PatientsA retrospective study was conducted on 47 adult women with microprolactinoma followed up between 1975 and 2010; none of them had undergone prior surgery or radiotherapy, and all of them received treatment with a dopamine agonist for at least 4 years. They were divided into two groups for analysis: cured patients with at least 4 years with normal prolactin levels after drug discontinuation, and not cured patients.ResultsCure was achieved in 57.4% of patients. Only age at diagnosis was a significant predictor: there were more young patients in the cured group and youngest patients needed less time to cure. Development of empty sella turcica or normal MRI were similar regarding time to cure.ConclusionsMicroprolactinoma may be cured with dopamine agonists, and life-long treatment is not required, although more than 10 years may be required to achieve cure, 11,6 ± 5,3 years in our experience.     

Is disruption of sleep quality a consequence of severe Covid-19 infection? A case-series examination

ABSTRACT

The Covid-19 outbreak put enormous stress on the health system worldwide, and objective data to handle the emergency are still needed. We aimed to objectively assess the consequence of severe symptoms of Covid-19 infection on sleep quality through wrist actigraphy monitoring of four patients during the sub-acute recovery stage of the disease. The sleep of those patients who had experienced the most severe respiratory symptoms and who had needed prolonged intensive care unit (ICU) stay showed lower Sleep Efficiency and Immobility Time and higher Fragmentation Index compared to those patients who had experienced only mild respiratory symptoms and not requiring ICU stay. Wrist actigraphy assessment provided important clinical information about the sleep and activity levels of Covid-19 patients during the post-acute rehabilitation management.     

Three Distinct Types of Monoclonal Antibodies After Long-Term Immunization of Rats with Mouse Nerve Growth Factor

This article reports the results of a systematic investigation of the different types of antibodies produced in the course of a long-term immunization of rats with mouse nerve growth factor (NGF). We have characterized three types of monoclonal antibodies, namely: (1) antibodies that bind to NGF and inhibit its binding to target cells and its biological activity in culture (type A); (2) antibodies that bind to and precipitate NGF but do not inhibit its binding to target cells or its biological activity (type B); (3) antibodies that fail to recognize NGF itself, but inhibit nonetheless its binding to target cells (type C). These antibodies bind to an antigen present on NGF target cells and not on rat fibroblasts lacking NGF receptor. They appear thus to be antiidiotypic antibodies directed against the NGF receptor, developed as a consequence of the long-term immunization with NGF.