Bacteriophages on dairy foods

This review focuses on the impact of bacteriophages on the manufacture of dairy foods. Firstly, the impact of phages of lactic acid bacteria in the dairy industry, where they are considered enemies, is discussed. The sources of phage contamination in dairy plants are detailed, with special emphasis on the rise of phage infections related to the growing use of cheese whey as ingredient. Other topics include traditional and new methods of phage detection, quantification and monitoring, and strategies of phage control in dairy plants, either of physical, chemical or biological nature. Finally, the use of phages or purified phage enzymes as allies to control pathogenic bacteria in the food industry is reviewed.Fil: Pujato, Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Lactología Industrial. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Lactología Industrial; ArgentinaFil: Quiberoni, Andrea del Lujan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Lactología Industrial. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Lactología Industrial; ArgentinaFil: Mercanti, Diego Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Lactología Industrial. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Lactología Industrial; Argentin

Efficient algorithms for tuple domination on co-biconvex graphs and web graphs

A vertex in a graph dominates itself and each of its adjacent vertices. The $k$-tuple domination problem, for a fixed positive integer $k$, is to find a minimum sized vertex subset in a given graph such that every vertex is dominated by at least k vertices of this set. From the computational point of view, this problem is NP-hard. For a general circular-arc graph and $k=1$, efficient algorithms are known to solve it (Hsu et al., 1991 & Chang, 1998) but its complexity remains open for $k\geq 2$. A $0,1$-matrix has the consecutive 0's (circular 1's) property for columns if there is a permutation of its rows that places the 0's (1's) consecutively (circularly) in every column. Co-biconvex (concave-round) graphs are exactly those graphs whose augmented adjacency matrix has the consecutive 0's (circular 1's) property for columns. Due to A. Tucker (1971), concave-round graphs are circular-arc. In this work, we develop a study of the $k$-tuple domination problem on co-biconvex graphs and on web graphs which are not comparable and, in particular, all of them concave-round graphs. On the one side, we present an $O(n^2)$-time algorithm for solving it for each $2\leq k\leq |U|+3$, where $U$ is the set of universal vertices and $n$ the total number of vertices of the input co-biconvex graph. On the other side, the study of this problem on web graphs was already started by Argiroffo et al. (2010) and solved from a polyhedral point of view only for the cases $k=2$ and $k=d(G)$, where $d(G)$ equals the degree of each vertex of the input web graph $G$. We complete this study for web graphs from an algorithmic point of view, by designing a linear time algorithm based on the modular arithmetic for integer numbers. The algorithms presented in this work are independent but both exploit the circular properties of the augmented adjacency matrices of each studied graph class.Comment: 21 pages, 7 figures. Keywords: $k$-tuple dominating sets, augmented adjacency matrices, stable sets, modular arithmeti

3D printer-controlled syringe pumps for dual, active, regulable and simultaneous dispensing of reagents. Manufacturing of immunochromatographic test strips

Lateral flow immunoassays (LFIA) are widely used worldwide for the detection of different analytes because they combine multiple advantages such as low production cost, simplicity, and portability, which allows biomarkers detection without requiring infrastructure or highly trained personnel. Here we propose to provide solutions to the manufacturing process of LFIA at laboratory-scale, particularly to the controlled and active dispensing of the reagents in the form the Test Lines (TL) and the Control Lines (CL). To accomplish this task, we adapted a 3D printer to also control Syringe Pumps (SP), since the proposed adaptation of a 3D printer is easy, free and many laboratories already have it in their infrastructure. In turn, the standard function of the 3D printer can be easily restored by disconnecting the SPs and reconnecting the extruder. Additionally, the unified control of the 3D printer enables dual, active, regulable and simultaneous dispensing, four features that are typically found only in certain high-cost commercial equipment. With the proposed setup, the challenge of dispensing simultaneously at least 2 lines (CL and TL) with SPs controlled by a 3D printer was addressed, including regulation in the width of dispensed lines within experimental limits. Also, the construction of a LFIA for the detection of leptospirosis is shown as a practical example of automatized reagent dispensing.Comment: 19 pages, 4 figure

Automatización del sistema de bombeo en el aprovisionamiento de agua potable a la ciudad de Nogoyá, Entre Ríos

En la provincia de Entre Ríos, los proveedores de agua potable y saneamiento a cargo de los municipios, no siempre dan prioridad a la inversión requerida. Este trabajo demuestra que es posible reducir los costos de producción con pequeños aumentos en los presupuestos asignados. Podrían conseguirse ahorros significativos además de preservar los recursos hídricos, a través de una adecuada planificación. La ciudad de Nogoyá tiene una población de alrededor de 25.000 personas. La red de agua potable cubre el 98%, abastecida por 10 pozos equipados con bombas sumergibles, que eran operados por un sistema manual - empírico. El objetivo se basó en alternar la operación de las bombas y la aplicación de la automatización de la operación para minimizar los gastos. Por el momento, se logró reducir los costos operativos entre 8 y 24% y disminuir los conos de depresión de bombeo.In the province of Entre Rios, suppliers of drinking water and sanitation in charge of municipalities, do not always prioritize the investment required.This work shows that it is possible to reduce costs of production with small increases in the assigned budgets. Significant savings could be achieved besides to preserve water resources through an appropriate planning. Nogoyá city has a population of around 25.000 people. The drinking water network covers 98%, supplied by 10 boreholes equipped with submersible pumps, which were operated by a manual - empirical system. The objective was based on alternating the pumps operation, implementing the automation of the operation to minimize expenses. At the moment, we managed to reduce operating costs between 8 and 24% and reduce pumping cones of depression.Universidad Nacional de La Plat

A free customizable tool for easy integration of microfluidics and smartphones

The integration of smartphones and microfluidics is nowadays the best possible route to achieve effective point-of-need testing (PONT), a concept increasingly demanded in the fields of human health, agriculture, food safety, and environmental monitoring. Nevertheless, efforts are still required to integrally seize all the advantages of smartphones, as well as to share the developments in easily adoptable formats. For this purpose, here we present the free platform appuente that was designed for the easy integration of microfluidic chips, smartphones, and the cloud. It includes a mobile app for end users, which provides chip identification and tracking, guidance and control, processing, smart-imaging, result reporting and cloud and Internet of Things (IoT) integration. The platform also includes a web app for PONT developers, to easily customize their mobile apps and manage the data of administered tests. Three application examples were used to validate appuente: a dummy grayscale detector that mimics quantitative colorimetric tests, a root elongation assay for pesticide toxicity assessment, and a lateral flow immunoassay for leptospirosis detection. The platform openly offers fast prototyping of smartphone apps to the wide community of lab-on-a-chip developers, and also serves as a friendly framework for new techniques, IoT integration and further capabilities. Exploiting these advantages will certainly help to enlarge the use of PONT with real-time connectivity in the near future.Fil: Schaumburg, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Vidocevich, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Gerlero, Gabriel Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Pujato, Nazarena. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Macagno, Joana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Kler, Pablo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Berli, Claudio Luis Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentin

Utility evaluation of two molecular methods for Leptospira spp. typing in human serum samples

Most of the available genotyping methods were applied and evaluated in Leptospira isolates and only few of them in a relevant sample size of blood specimens but not of sera. The objective of this study was to evaluate the utility of one partial 16S rRNA gene sequencing assay (16S rRNA) and an optimized. Multilocus sequence typing scheme (MLST) for Leptospira typing directly in serum samples. Confirmed leptospirosis patients (n = 228) from Argentina (2005–2016) were randomly included. Septicemic-phase serum samples (n = 228) were studied by two genotyping methods. Available immune-phase serum samples of the included patients (n = 159) were studied by MAT to compare serological and molecular results. In culture-proven cases (n = 8), genotyping results between clinical samples and isolates were compared. Typing success rate (TSR) was 21.9% for 16S rRNA and 11.4% for MLST (full allelic profile) and a positive trend in both TSR during the study period was observed. Two species (L. interrogans and L. borgpertesenii) were identified by both methods and MLST assigned 8 different STs. The probable serogroups identified by MLST were coincident with the presumptive infecting serogroups identified by MAT, but with different frequencies. The three serogroups (Canicola, Sejroe and Icterohaemorrhagiae) most frequently identified by MAT were also genotyped by MLST. Typing results via 16S rRNA and MLST in clinical samples and isolates of culture-proven cases, were consistent except for one case. Performance of partial 16S rRNA gene sequencing assay and the optimized MLST scheme directly in sera may increase and improve the knowledge about species and serogroups causing human leptospirosis, especially in countries with low rates of culture sample collection or Leptospira isolation.Fil: Landolt, Noelia Yolanda. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorios e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Respiratorias; ArgentinaFil: Chiani, Yosena Teresita. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorios e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Respiratorias; ArgentinaFil: Pujato, Nazarena. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorios e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Respiratorias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Jacob, Paulina. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorios e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Respiratorias; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Schmeling, Maria Fernanda. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorios e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Respiratorias; ArgentinaFil: Garcia, Guillermo Manuel. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Vanasco, Norma Bibiana. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorios e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Respiratorias; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentin

Haemonchus contortus con resistencia múltiple a los antihelmínticos de corta y larga acción y consideraciones sobre el impacto sanitario-productivo de este fenómeno en una majada de ovinos lecheros de la provincia de Santa Fe

Entre Octubre y Noviembre del 2012 se realizaron evaluaciones sobre la actividad de cuatro antihelmínticos con diferente mecanismo de acción (levamisol, ivermectina, closantel y febendazol) en ovinos lecheros naturalmente parasitados por nematodes gastrointestinales en un establecimiento del área central de Santa Fe. Las determinaciones de susceptibilidad o resistencia se realizaron a través del test de reducción en el conteo de huevos (TRCH) y como animales experimentales se utilizaron 40 corderos destetados de la raza Pampinta de aproximadamente dos meses y medio de edad. Estos animales fueron asignados a cuatro grupos de tratamientos de diez animales cada uno en función del número de huevos de nematodes por gramo de heces o hpg (p>0,005). El TRCH se determinó estableciendo el porcentaje de reducción observado en el promedio del hpg en las muestras de materia fecal pre y post tratamiento de los mismos animales. Los resultados indicaron la presencia predominante de Haemonchus contortus con resistencia múltiple a ivermectina, febendazol y clo-santel así como de Nematodirus spp con resistencia a las dos primeras de estas drogas. El levamisol presentó una eficacia muy alta (> al 99 %) para controlar cualquiera de estos aislamientos. Ante la presencia de resistencia con los otros antihelmínticos, todos los corderos experimentales fueron re-tratados con levamisol observándose en este segundo TRCH una eficacia similar al primero. No obstante, debido a su baja actividad larvicida y su corta acción, aproximadamente 30 días posteriores al tratamiento de todos los corderos con levamisol se produjo un severo caso de haemonchosis con elevados índices de mortalidadBetween October and November 2012 a field trial was carried out in dairy sheep naturally parasi-tized by gastrointestinal nematodes in central Santa Fe (Argentina) to investigate the activity of four anthelmintic with different mechanism of action (levamisole, ivermectin, fenbendazole and closantel). The status of susceptibility or resistance was performed through the test of reduction in egg count (TRCH) on 40 Pampinta lambs about two and half months old. These lambs were assigned to four treatment groups of ten animals each according to the number of nematode eggs per gram of feces or hpg (p> 0.005). TRCH was determined by establishing the percentage reduction in the average observed epg in fecal samples before and after treatment of the same animals. The results indicated the predominance of Haemonchus contortus with multiple resistance to ivermectin, febendazole and closantel as well as Nematodirus spp with resistance to the first two of these drugs. Levamisole showed a very high efficacy (> 99%) to control any of these isolates. Due to the presence of Haemonchus spp with resistance to ivermectin, febendazole and closantel, all experimental lambs were re-treated with levamisole and similar efficacy in the TRCH was observed in this second trial. However, due to its low larvicidal activity and short action, approximately 30 days after levamisol treatment, a severe outbreak of acute haemonchosis with high mortality rates was observedEEA RafaelaFil: Muchiut, Sebastian. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; ArgentinaFil: Mildenberger, M. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; ArgentinaFil: Pujato, Andrés. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; ArgentinaFil: Anziani, Oscar Sergio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentin

Variabilidad 3d de las aguas subterráneas en el Delta del Río Paraná. Argentina

En los sistemas costeros, el asumir simplificaciones de que los flujos se comportan bidimensionalmente, puede llevar a obtener conclusiones que no representen el real funcionamiento del sistema natural. En el caso el Delta del Río Paraná, esta variación temporo-espacial alcanza mayor magnitud. El sistema actúa con características de flujo 3D, con mayor variabilidad en estiajes y/o crecidas prolongadas del Río Paraná, al ser esta la condición de borde temporal que tiene el mayor impacto en el sistema. La superposición de estos efectos, producen limitaciones en la productividad del sistema, por lo que es incapaz de sustentar a una población estable. El objetivo ha sido el de caracterizar el impacto de las aguas subterráneas en el sistema ambiental-productivo del Delta del Río Paraná, su vinculación con las áreas de descarga y sus efectos en la variación en vertical de la salinidad.In coastal systems, the simplifications assume that two-dimensional flows behave can lead to draw co nclusions that do not represent the actual natural system. For the Parana River Delta, the spatial-temporal variation achieves greater magnitude. The system works with 3D flow characteristics, with greater variability in droughts and / or floods prolonged Paraná River, as this is the temporal boundary condition that has the greatest impact on the system. The superposition of these effects, constraints occur in the system productivity, so is unable to sustain a stable population. The aim has been to characterize the impact of groundwater in the environmental system-productive Parana River Delta, its connection with the discharge areas and their effects on the vertical variation in salinity.Universidad Nacional de La Plat

Leuconostoc mesenteroides and Leuconostoc pseudomesenteroides bacteriophages: Genomics and cross-species host ranges

Unveiling virus-host interactions are relevant for understanding the biology and evolution of microbes globally, but in particular, it has also a paramount impact on the manufacture of fermented dairy products. In this study, we aim at characterizing phages infecting the commonly used heterofermentative Leuconostoc spp. on the basis of host range patterns and genome analysis. Host range of six Leuconostoc phages was investigated using three methods (efficiency of plaquing, spot and turbidity tests) against Ln. mesenteroides and Ln. pseudomesenteroides strains. Complete genome sequencing from four out of the six studied Leuconostoc phages were obtained in this work, while the remaining two have been sequenced previously. According to our results, cross-species host specificity was demonstrated, as all phages tested were capable of infecting both Ln. pseudomesenteroides and Ln. mesenteroides strains, although with different efficiency of plaquing (EOP). Phage adsorption rates and ability of low-EOP host strains to propagate phages by crossing the Leuconostoc species' barrier confirm results. At the genome level, phages CHA, CHB, Ln-7, Ln-8 and Ln-9 revealed high similarity with previously characterized phages infecting mostly Ln. mesenteroides strains, while phage LDG was highly similar to phages infecting Ln. pseudomesenteroides. Additionally, correlation between receptor binding protein (RBP) and host range patterns allowed us to unveil a finer clustering of Leuconostoc phages studied into four groups. This is the first report of overlapped phage host ranges between Leuconostoc species.This work was supported by the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET; Project PIP 112-201201-00046; Argentina), the Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT; Project PICT 2010-0138; Argentina) and the Universidad Nacional del Litoral (UNL, Project CAI+D PI 501 201101 00039 LI; Argentina). S.A.P. was the recipient of an international scholarship awarded by BEC.AR (Becas de formación en el exterior en Ciencia y Tecnología, Presidencia de la Nación, Argentina). M.M.G. thanks Ministerio de Economía y Competitividad (refs. CGL2013-40564-R and SAF2013-49267-EXP), Generalitat Valenciana (ACOMP/2015/133) and Gordon and Betty Moore Foundation (Grant award ref. 5334). F.J.M.M. is funded by the Spanish Ministerio de Economía y Competitividad (BIO2014-53029P) and the European Commission/Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (291815 Era-Net ANIHWA)