Consistent determination of the heating rate of light-absorbing aerosol using wavelength- and time-dependent Aethalometer multiple-scattering correction.

Accurate and temporally consistent measurements of light absorbing aerosol (LAA) heating rate (HR) and of its source apportionment (fossil-fuel, FF; biomass-burning, BB) and speciation (black and brown Carbon; BC, BrC) are needed to evaluate LAA short-term climate forcing. For this purpose, wavelength- and time-dependent accurate LAA absorption coefficients are required. HR was experimentally determined and apportioned (sources/species) in the EMEP/ACTRIS/COLOSSAL-2018 winter campaign in Milan (urban-background site). Two Aethalometers (AE31/AE33) were installed together with a MAAP, CPC, OPC, a low volume sampler (PM2.5) and radiation instruments. AE31/AE33 multiple-scattering correction factors (C) were determined using two reference systems for the absorption coefficient: 1) 5-wavelength PP_UniMI with low time resolution (12 h, applied to PM2.5 samples); 2) timely-resolved MAAP data at a single wavelength. Using wavelength- and time-independent C values for the AE31 and AE33 obtained with the same reference device, the total HR showed a consistency (i.e. reproducibility) with average values comparable at 95% probability. However, if different reference devices/approaches are used, i.e. MAAP is chosen as reference instead of a PP_UniMI, the HR can be overestimated by 23-30% factor (by both AE31/AE33). This became more evident focusing on HR apportionment: AE33 data (corrected by a wavelength- and time-independent C) showed higher HRFF (+24 ± 1%) and higher HRBC (+10 ± 1%) than that of AE31. Conversely, HRBB and HRBrC were -28 ± 1% and -29 ± 1% lower for AE33 compared to AE31. These inconsistencies were overcome by introducing a wavelength-dependent Cλ for both AE31 and AE33, or using multi-wavelength apportionment methods, highlighting the need for further studies on the influence of wavelength corrections for HR determination. Finally, the temporally-resolved determination of C resulted in a diurnal cycle of the HR not statistically different whatever the source- speciation- apportionment used.

Advances on the immunotoxicity of outdoor particulate matter: A focus on physical and chemical properties and respiratory defence mechanisms.

Particulate matter (PM) is acknowledged to have multiple detrimental effects on human health. In this review, we report literature results on the possible link between outdoor PM and health outcomes with a focus on pulmonary infections and the mechanisms responsible for observed negative effects. PM physical and chemical properties, such as size and chemical composition, as well as major emission sources are described for a more comprehensive view about the role played by atmospheric PM in the observed adverse health effects; to this aim, major processes leading to the deposition of PM in the respiratory tract and how this can pave the way to the onset of pathologies are also presented. From the literature works here reviewed, two ways in which PM can threaten human health promoting respiratory infectious diseases are mostly taken into account. The first pathway is related to an enhanced susceptibility and here we will also report on molecular mechanisms in the lung immune system responsible for the augmented susceptibility to pathogens, such as the damage of mechanical defensive barriers, the alteration of the innate immune response, and the generation of oxidative stress. The second one deals with the relationship between infectious agents and PM; here we recall that viruses and bacteria (BioPM) are themselves part of atmospheric PM and are collected during sampling together with particles of different origin; so, data should be analysed with caution in order to avoid any false cause-effect relation. To face these issues a multidisciplinary approach is mandatory as also evident from the ongoing research about the mechanisms hypothesized for the SARS-CoV-2 airborne spreading, which is still controversial and claims for further investigation. Therefore, we preferred not to include papers dealing with SARS-CoV-2.

Biomonitoring of the adult population living near the waste incinerator of Turin: Serum concentrations of PCDDs, PCDFs, and PCBs after three years from the plant start-up.

In September 2013 a waste-to-energy (WTE) incinerator located in the Turin area (Piedmont, Northern Italy) started to produce energy by the incineration of municipal solid wastes. The plant, one of the largest WTE incinerator in Europe, burns up to 490,000 tons of waste per year. A health surveillance program was implemented in order to evaluate the potential health effects on the population living near the plant. This program included a biomonitoring study aimed at assessing levels of several environmental contaminants including, among others, PCDDs, PCDFs, and PCBs. Before the WTE incinerator start-up (T0), a group of 85 subjects (41 "exposed" and 44 "not exposed" subjects) was randomly selected for enrollment by the local health units among individuals aged 36-50 years who had been living in the same area for at least five years prior to the study. Subjects were balanced by exposure area, sex and five-year age classes. As from the study design, the same cohort was re-evaluated after three years of incinerator activity (T2). A parallel study was conducted on a group of 12 farmers living and/or working in farms located in an area in the range of 5 km around the incinerator. Results of this study did not evidence any impact of the WTE plant on human exposure to PCDDs, PCDFs, and PCBs. In fact, no significant differences were found in the concentrations of PCDDs + PCDFs, DL-PCBs, and NDL-PCBs measured in the population group residing near the plant after three years of activity (T2) with respect to the control group. A significant decrease of serum concentrations of all the analytes was observed at T2 in both groups compared to T0. Serum concentrations of PCDDs, PCDFs, and PCBs in the group of farmers were higher than those observed in the adult population under study.

Differential expression of RNA exosome subunits in the amphibian Lithobates catesbeianus during reproductive and non-reproductive periods.

OBJECTIVE: The RNA exosome is an evolutionarily conserved 3'-5' exoribonucleolytic protein complex involved in processing and degradation of different classes of nuclear and cytoplasmic RNAs, and, therefore, important for the posttranscriptional control of gene expression. Despite the extensive in vivo functional studies and the structural data on the RNA exosome, few studies have been performed on the localization and expression of exosome subunits during gametogenesis, process during which gene expression is largely controlled at the posttranscriptional level. RESULTS: We report the identification of exosome subunits in Lithobates catesbeianus and analysis of the differential subcellular localization of RNA exosome core and catalytic subunits in testis cells. In addition, we show seasonal differences in the expression levels of four exosome subunits in different organs. In addition to being part of the RNA exosome complex, its subunits might participate independently of the complex in the control of gene expression during seasonal variation in bullfrog tissues. These results may be relevant for other eukaryotic species.

Assessment of light extinction at a European polluted urban area during wintertime: Impact of PM1 composition and sources.

In this paper, results from receptor modelling performed on a well-characterised PM1 dataset were combined to chemical light extinction data (bext) with the aim of assessing the impact of different PM1 components and sources on light extinction and visibility at a European polluted urban area. It is noteworthy that, at the state of the art, there are still very few papers estimating the impact of different emission sources on light extinction as we present here, although being among the major environmental challenges at many polluted areas. Following the concept of the well-known IMPROVE algorithm, here a tailored site-specific approach (recently developed by our group) was applied to assess chemical light extinction due to PM1 components and major sources. PM1 samples collected separately during daytime and nighttime at the urban area of Milan (Italy) were chemically characterised for elements, major ions, elemental and organic carbon, and levoglucosan. Chemical light extinction was estimated and results showed that at the investigated urban site it is heavily impacted by ammonium nitrate and organic matter. Receptor modelling (i.e. Positive Matrix Factorization, EPA-PMF 5.0) was effective to obtain source apportionment; the most reliable solution was found with 7 factors which were tentatively assigned to nitrates, sulphates, wood burning, traffic, industry, fine dust, and a Pb-rich source. The apportionment of aerosol light extinction (bext,aer) according to resolved sources showed that considering all samples together nitrate contributed at most (on average 41.6%), followed by sulphate, traffic, and wood burning accounting for 18.3%, 17.8% and 12.4%, respectively.

A new surgical positioning system for robotic assisted minimally invasive spine surgery and transpedicular approach to the disc.

Minimally Invasive Spine Surgery (MISS) procedures for the treatment of spinal pathologies have experienced exponential growth due to improved techniques and decreased trauma to the patient. Several MISS procedures that require the use of a trans-pedicular cannula as a guiding tool for pedicle screw placement, delivery of biomaterials to the vertebral body or injection of biologics to the disc space have been described. Although these are clear advantages of MISS, the limited dissection and exposure may reduce the accuracy and stability of operation and make spine surgeons rely heavily on intraoperative fluoroscopy, raising concerns over the level of radiation exposure. Robot-assisted minimal invasive surgery has aroused more attention for its high precision and stability, minimizing risks of damage to neurovascular structures and diminishing harmful exposure to ionizing radiation. The aim of this paper is to describe and characterize a new surgical positioning system for for robotic assisted MISS. The system is conceived to be integrated in a surgical platform capable of supporting the surgeon in a new procedure to treat degenerative intervertebral disc disease. For this purpose, it is necessary to orientate a cannula in order to guide the bone drill along a planned route, to access the intervertebral disc through the pedicle and endplate. In particular, we describe a mechanism that percutaneously guides a cannula towards the intervertebral disc based on the acquisition of few fluoroscopic images. The design of the positioning system, with its features and constrains imposed by the presence of instrumentation and medical staff in the operating room, as well as the software for trajectory planning during surgery, are here described.

Size-segregated aerosol in a hot-spot pollution urban area: Chemical composition and three-way source apportionment.

In this work, a comprehensive characterisation and source apportionment of size-segregated aerosol collected using a multistage cascade impactor was performed. The samples were collected during wintertime in Milan (Italy), which is located in the Po Valley, one of the main pollution hot-spot areas in Europe. For every sampling, size-segregated mass concentration, elemental and ionic composition, and levoglucosan concentration were determined. Size-segregated data were inverted using the program MICRON to identify and quantify modal contributions of all the measured components. The detailed chemical characterisation allowed the application of a three-way (3-D) receptor model (implemented using Multilinear Engine) for size-segregated source apportionment and chemical profiles identification. It is noteworthy that - as far as we know - this is the first time that three-way source apportionment is attempted using data of aerosol collected by traditional cascade impactors. Seven factors were identified: wood burning, industry, resuspended dust, regional aerosol, construction works, traffic 1, and traffic 2. Further insights into size-segregated factor profiles suggested that the traffic 1 factor can be associated to diesel vehicles and traffic 2 to gasoline vehicles. The regional aerosol factor resulted to be the main contributor (nearly 50%) to the droplet mode (accumulation sub-mode with modal diameter in the range 0.5-1 µm), whereas the overall contribution from the two factors related to traffic was the most important one in the other size modes (34-41%). The results showed that applying a 3-D receptor model to size-segregated samples allows identifying factors of local and regional origin while receptor modelling on integrated PM fractions usually singles out factors characterised by primary (e.g. industry, traffic, soil dust) and secondary (e.g. ammonium sulphate and nitrate) origin. Furthermore, the results suggested that the information on size-segregated chemical composition in different size classes was exploited by the model to relate primary emissions to rapidly-formed secondary compounds.

Functionality and opposite roles of two interleukin 4 haplotypes in immune cells.

Cytokines expression can be influenced by polymorphisms in their respective coding genes. We associated the CTI/TTD haplotype (Hap-1) and TCI/CCI haplotype (Hap-2) in the IL4 gene formed by the -590, +33 and variable number of tandem repeat polymorphisms with the severity of chronic periodontitis in humans. The functionality of these IL4 haplotypes in the response of immune cells to phorbol 12-myristate 13-acetate (PMA) with Ionomycin and IL-1ß (as inflammatory stimuli) was evaluated. Gene expression (quantitative real-time PCR), profile of secreted cytokines (multiplex) and phenotypic polarization of T cells (flow cytometry) were the outcomes assessed. Green fluorescent protein reporter plasmid constructs containing specific IL4 haplotype were transiently transfected into JM cells to assess the influence of the individual haplotypes on promoter activity. In response to inflammatory stimuli the immune cells from Hap-1 haplotype had increased expression of anti-inflammatory IL4; conversely, the Hap-2 haplotype showed higher levels of pro-inflammatory cytokines. The haplotype CTI proved to be the most important for the regulation of IL4 promoter, regardless of the nature of the inflammatory stimulation; whereas the polymorphism in the promoter region had the least functional effect. In conclusion, IL4 haplotypes studied are functional and trigger opposite immune responses: anti-inflammatory (Hap-1) and pro-inflammatory (Hap-2). In addition, we identified the CTI haplotype as the main responsible for the regulation of IL4 transcriptional activity.

Occupational exposure to PCDDs, PCDFs, and DL-PCBs in metallurgical plants of the Brescia (Lombardy Region, northern Italy) area.

The concentration values of polychlorodibenzodioxins (PCDDs), polychlorodibenzofurans (PCDFs), and dioxin-like polychlorobiphenyls (DL-PCBs) in blood serum samples (pools) of metallurgical workers in the area of the city of Brescia (northern Italy) were statistically processed. As to workers' exposure characteristics, pools were divided into 34 professionally exposed (PE) and 11 non-professionally exposed (NPE). A further subdivision of PE pools was according to workplaces in which ferrous (N = 24) and non-ferrous (N = 10) materials were handled. To evaluate the aforesaid differences we applied the age-adjusted Generalized Linear Models. We identified significant (P ≤ 0.05) exposure models of the classification groups. The first subdivision was confirmed by the concentrations of 1,2,3,4,6,7,8-H7CDF, DL-PCB 105, and DL-PCB 189; the second was confirmed by the concentrations of PCDF TEQ97, PCDD + PCDF + DL-PCB (TEQTOT) TEQ97, 2,3,4,7,8-P5CDF, 1,2,3,6,7,8-H6CDD, 1,2,3,4,6,7,8-H7CDD, and PCB 189. Based on the literature, all mentioned congeners have been found in stack gas and fly ash samples of metallurgical plants: therefore, these indicators indicate the exposure to such work environments. Specifically, the concentrations measured in the workers' blood serum appear to depend on the type of material processed during work.

Evaluation of mean echogenicity of tendons and ligaments of the metacarpal region in neonatal foals: A preliminary study.

The aims of this research were to evaluate mean echogenicity (ME) of the deep and superficial digital flexor tendons (DDFT and SDFT), the interosseous muscle (IM), and the accessory ligament of the deep digital flexor tendon (ALDDFT) of the metacarpal region in neonatal foals, and determine the effect of sex, side and body weight on this quantitative ultrasonographic evaluation. Thirteen orthopedically sound neonatal foals were examined. Four areas of study (1A, 1B, 2A, 2B) were identified. Transverse scans of the DDFT, SDFT, IM and ALDDFT were obtained, recorded, and analyzed. The most echogenic structures were the ALDDFT and DDFT, while the SDFT was significantly less echogenic than all other structures (P<0.05). No influence of sex, forelimb, or body weight was observed. The echogenicity of the tenodesmic structures of foals partially overlapped that reported in the metacarpal region in adult horses, except for IM.

A theoretical framework for studying the electromagnetic stimulation of nervous tissue.

In this paper we present a model for calculating the electric field, and its spatial derivatives, produced by arbitrarily shaped, oriented and placed coils carrying time-varying currents. The model has been validated by comparing its results with those obtained using FEM simulations. The model provides a simple and fast computation framework to investigate the electromagnetic stimulation of neural tissues. Some example applications are also provided.

Monte Carlo as a tool to evaluate the effect of different lung densities on radiotherapy dose distribution.

This study aims at evaluating the effects of different lung densities on dose distribution after irradiation at different field sizes, by comparing experimental measurements, GEANT4 Monte Carlo (MC) simulations and two TPS calculation algorithms on ad hoc phantoms. Irradiations were performed with a Varian Clinac 2100 C/D with a nominal energy of 6 MV. Dosimetric experimental measurements were obtained with radiochromic films. A model based on GEANT4 MC code was developed to simulate both the accelerator and the phantoms. Results of dose distribution show an acceptable agreement between MC simulations and experimental measurements, both in the tumour-equivalent region and in the normal tissue-equivalent ones. On the opposite, results vary among the TPS algorithms, especially in regions of lung-equivalent material at low density, but also at the interface between lung- and tumour-equivalent materials.

New ligands of the Cellular Retinoic Acid-Binding Protein 2 (CRABP2) suggest a role for this protein in chromatin remodeling

Retinoic acid (RA) regulates the transcription of a series of genes involved in cell proliferation, differentiation and apoptosis by binding to the RA Receptor (RAR) and Retinoid X Receptor (RXR) heterodimers. The cellular retinoic acid-binding protein 2 (CRABP2) is involved in the transport of RA from the cytosol to specific RA receptors in the nucleus, acting as a coactivator of nuclear retinoid receptors. In order to have a better understanding of the role of CRABP2 in RA signaling, we used the yeast two-hybrid system as a tool for the identification of physical protein-protein interactions. Twenty-three putative CRABP2-interacting proteins were identified by screening in the presence of RA, five of which are related to transcription regulation or, more specifically, to the process of chromatin remodeling: t-complex 1 (TCP1); H3 histone, family 3A (H3F3A); H3 histone, family 3B (H3F3B); β-tubulin (TUBB) and SR-related CTD-associated factor 1 (SCAF1). These results suggest a more direct role for CRABP2 in chromatin remodeling and may be a starting point for the elucidation of the fine-tuning control of transcription by RA receptors...

[Cumulative exposure to polychlorodibenzo-p-dioxins (PCDDS), polychlorodibenzofurans (PCDFS) and polychlorobiphenyls (PCB) in the metallurgic workers and the general population in Brescia province, northern Italy]. / Esposizione cumulativa a policlorodibenzodiossine (PCDD), policlorodibenzofurani (PCDF) e policlorobifenili (PCB) in lavoratori metallurgici e nella popolazione generale della provincia di Brescia.

High temperature metallurgical processes may significantly contribute to the release of polychlorodibenzo-p-dioxins (PCDDs) and polychlorodibenzofurans (PCDFs) into the environment. Aim of this study was to evaluate the exposure to PCDDs, PCDFs, dioxin-like PCBs (DL-PCBs) and non dioxin-like PCBs (NDL-PCBs) in a sample of 300 workers of metallurgical plants operating in the Brescia area and in a control group of 113 men. Serum samples were grouped in pools of 10 and analyzed for their concentration of PCDDs and PCDFs, DL- and NDL-PCBs. Metallurgical workers show serum concentrations of NDL-PCBs similar to those observed in non-occupationally exposed living in Brescia, except in the case of some congeners, such as PCBs 28, 52, 101 which result to be significantly higher in metallurgical workers. Their concentrations range of "dioxins" was of 32.5 - 84.8 pgTEQ g(-1) lb. No significant difference was found between metallurgical workers and the control group on the whole, but the difference became significant when comparing metallurgical workers with the group of the 47 subjects living in remote non industrialised areas. In conclusion, concentrations of total PCBs observed in metallurgy workers are comparable with those observed in the control group, with the exception of a few, more volatile, congeners which resulted to be higher in metallurgy workers. Concentrations of PCDDs and PCDFs showed a range of values similar to that observed in the general population of Brescia not professionally exposed. However, concentrations of PCDDs and PCDFs observed in subjects resident in "remote" areas were significantly lower than those assessed in metallurgy workers and subjects living in the town of Brescia. On the whole, men living in the town of Brescia show levels of PCBs, PCDDs and PCDFs higher than those observed in other groups of the Italian general population, this reflecting the intense industrial activity of the town.

Papel da proteína Mx1 na resposta a interferons e no processo neoplásico / Role of Mx1 protein in the response to interferons and neoplastic process

A proteína Mx1 é codificada por um gene induzido por interferon e compartilha a organização de seus domínios, a capacidade de homo-oligomerização e associação com membranas com as grandes dinaminas GTPases. A proteína Mx1 está envolvida na resposta contra um grande número de vírus de RNA, como aqueles pertencentes à família Buniavírus e o vírus influenza. Curiosamente, o gene MX1 foi encontrado como silenciado por metilação em diversos processos neoplásicos, incluindo carcinomas de cabeça e pescoço de células escamosas. Neste cenário, o silenciamento gênico de MX1 está associado à imortalização de uma série de linhagens celulares neoplásicas. Assim, Mx1 se destaca como uma das principais proteínas envolvidas nas respostas imunes induzidas por interferon e também desempenha um importante papel no controle do ciclo celular. Aqui discutimos os aspectos funcionais da proteína Mx1 abordando sua atividade antiviral, organização estrutural, envolvimento com neoplasias e, principalmente, os aspectos funcionais obtidos pela determinação de seus parceiros celulares.

The Mx1 protein is encoded by an interferon-induced gene and shares domain organization, homo-oligomerization capacity and membrane association with the large dynamin-like GTPases. The Mx1 protein is involved in the response to a large number of RNA viruses, such as the bunyavirus family and the influenza virus. Interestingly, it has also been found as a methylation-silenced gene in several types of neoplasm, including head and neck squamous cell carcinoma. In this scenario, MX1 gene silencing is associated with immortalization in several neoplastic cell lines. Thus, Mx1 stands out as one of the key proteins involved in interferon-induced immune response and also plays an important role in cell cycle control. Here we discuss some of the functions of the Mx1 protein, including its antiviral activity, protein folding and involvement in neoplasia, as well as those revealed by investigating its cellular partners.

Studies on the effects of phosphine on Salmonella enterica serotype Enteritidis in culture medium and in black pepper (Piper nigrum).

The effect of phosphine on Salmonella enterica serotype Enteritidis inoculated in culture medium and in black pepper grains (Piper nigrum), as well as on the reduction of the microbial load of the dried and moisturized product, was verified. The postfumigation effect was verified in inoculated samples with 0.92 and 0.97 water activity (a(w)) exposed to 6 g/m(3) phosphine for 72 h, dried to 0.67 a(w), and stored for 24, 48, and 72 h. No decreases were observed in Salmonella Enteritidis populations in culture medium when fumigant concentrations up to 6 g/m(3) were applied for 48 h at 35°C. However, the colonies showed reductions in size and atypical coloration as the phosphine concentration increased. No reduction in Salmonella counts occurred on the inoculated dried samples after fumigation. On the other hand, when phosphine at concentrations of 6 g/m(3) was applied on moisturized black pepper for 72 h, decreases in Salmonella counts of around 80% were observed. The counts of total aerobic mesophilic bacterium populations of the dried and moisturized black pepper were not affected by the fumigant treatment. The results of the postfumigation studies indicated that Salmonella Enteritidis was absent in the fumigated grains after drying and storage for 72 h, indicating a promising application for this technique. It was concluded that for Salmonella Enteritidis control, phosphine fumigation could be applied to black pepper grains before drying and the producers should rigidly follow good agricultural practices, mainly during the drying process, in order to avoid product recontamination. Additional work is needed to confirm the findings with more Salmonella serotypes and strains.

Recurrent rotavirus diarrhoea outbreaks in a stud farm, in Italy.

A total of 47 stool samples were collected at the same stud farm from young foals with rotavirus diarrhoea and from their stud mares. Illness involved foals during three consecutive winter seasons. Infection in the farm appeared firstly in January-February 2008. After vanishing in the warm seasons, cases reappeared in March 2009 and 2010. Determination of the rotavirus G- and P-types was carried out using nested RT-PCR in samples collected in 2009 and 2010. A total of 19 of 47 samples resulted positive for rotavirus. The G type was determined in 19/47 samples, whereas the P genotype was determined in 17/47 samples. All equine strains presented a G14 VP7 in combination with a P[12] VP4, suggesting persistence of the same viral strain in the stud farm, during at least two consecutive winter periods. Sequence analysis of the genes encoding the outer capsid rotavirus proteins VP7 and VP4 revealed that the virus had a close relationship between strains recently isolated in the rest of Europe.

Obtenção de derivado de celulose a partir do bagaço de cana-de-açúcar com potencial aplicação nas indústrias farmacêutica e cosmética / Assessment of a gel derived from sugarcane bagasse cellulose

A tendência de se buscar o desenvolvimento de novos veículos agregando sustentabilidade e qualidade é o desafio da pesquisa farmacêutica. Assim, a busca de novas fontes de matéria-prima parece ocupar uma grande parcela dos estudos e investimentos do setor farmacêutico. Desse modo, a celulose é um exemplo de matéria-prima com alta aplicabilidade nas indústrias farmacêutica e cosmética. Temos na natureza algumas espécies de angiospermas com potencial fornecimento de celulose, tais como coco, bambu, cana-de-açúcar, entre outras. Destas, o bagaço de cana-de-açúcar apresenta teores de celulose significativos para obtenção de compostos derivados. O Brasil ocupa o primeiro lugar na produção de etanol e açúcar através da utilização da cana-de-açúcar. O presente trabalho teve como objetivo avaliar uma dispersão obtida a partir de um composto derivado da celulose extraída do bagaço de cana-de-açúcar.

The development of new vehicles combining sustainability and quality is a challenge facing pharmaceutical research. Thus, the search for novel raw material sources seems to occupy a great portion of the studies and investments of the pharmaceutical sector. One example of such a raw material with wide applicability in the pharmaceutical and cosmetics industries is cellulose. There are several angiosperm species with potential as suppliers of cellulose, such as coconut, bamboo and sugarcane, to name a few found in Brazil. Bagasse, the fibrous residue from crushed sugarcane, has a significant cellulose content from which new compounds can be derived. Brazil currently occupies first place in the production of ethanol and sugar from sugarcane. The aim of the present study was to assess a dispersion obtained from a derivative of the cellulose extracted from sugarcane pulp.

Functional significance of eIF5A and its hypusine modification in eukaryotes.

The unusual basic amino acid, hypusine [N(epsilon)-(4-amino-2-hydroxybutyl)-lysine], is a modified lysine with the addition of the 4-aminobutyl moiety from the polyamine spermidine. This naturally occurring amino acid is a product of a unique posttranslational modification that occurs in only one cellular protein, eukaryotic translation initiation factor 5A (eIF5A, eIF-5A). Hypusine is synthesized exclusively in this protein by two sequential enzymatic steps involving deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH). The deoxyhypusine/hypusine synthetic pathway has evolved in archaea and eukaryotes, and eIF5A, DHS and DOHH are highly conserved suggesting a vital cellular function of eIF5A. Gene disruption and mutation studies in yeast and higher eukaryotes have provided valuable information on the essential nature of eIF5A and the deoxyhypusine/hypusine modification in cell growth and in protein synthesis. In view of the extraordinary specificity and functional significance of hypusine-containing eIF5A in mammalian cell proliferation, eIF5A and the hypusine biosynthetic enzymes are novel potential targets for intervention in aberrant cell proliferation.