The Yersinia enterocolitica Ysa type III secretion system is expressed during infections both in vitro and in vivo.

Yersinia enterocolitica biovar 1B maintains two type III secretion systems (T3SS) that are involved in pathogenesis, the plasmid encoded Ysc T3SS and the chromosomally encoded Ysa T3SS. In vitro, the Ysa T3SS has been shown to be expressed only at 26°C in a high-nutrient medium containing an exceptionally high concentration of salt - an artificial condition that provides no clear insight on the nature of signal that Y. enterocolitica responds to in a host. However, previous research has indicated that the Ysa system plays a role in the colonization of gastrointestinal tissues of mice. In this study, a series of Ysa promoter fusions to green fluorescent protein gene (gfp) were created to analyze the expression of this T3SS during infection. Using reporter strains, infections were carried out in vitro using HeLa cells and in vivo using the mouse model of yersiniosis. Expression of green fluorescent protein (GFP) was measured from the promoters of yspP (encoding a secreted effector protein) and orf6 (encoding a structural component of the T3SS apparatus) in vitro and in vivo. During the infection of HeLa cells GFP intensity was measured by fluorescence microscopy, while during murine infections GFP expression in tissues was measured by flow cytometry. These approaches, combined with quantification of yspP mRNA transcripts by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), demonstrate that the Ysa system is expressed in vitro in a contact-dependent manner, and is expressed in vivo during infection of mice

Millimeter Wave Communications

Millimeter wave (mmWave) technologies promise to revolutionize wireless networks by enabling multi-gigabit data rates. However, they suffer from high attenuation, and hence have to use highly directional antennas to focus their power on the receiver. Existing radios have to scan the space to find the best alignment between the transmitter’s and receiver’s beams, a process that takes up to a few seconds. This delay is problematic in a network setting where the base station needs to quickly switch between users and accommodate mobile clients. We present Agile-Link, the first mmWave beam steering system that is demonstrated to find the correct beam alignment without scanning the space. Instead of scanning, Agile- Link hashes the beam directions using a few carefully chosen hash functions. It then identifies the correct alignment by tracking how the energy changes across different hash functions. Our results show that Agile-Link reduces beam steering delay by orders of magnitude.National Science Foundation (U.S.

Alunos matriculados em contextos de formação docente do Ensino de Inglês. Experiência e afeto

This article is the result of qualitative research with a narrative approach in which we initially sought to inquire about the contribution of students enrolled in the subject Writing Process I of the English Teacher Training Program at Universidad Nacional de Mar del Plata. For this purpose, we conducted questionnaires to the entire group of students who had taken the course in 2019. Then, we proceeded to search for first-person accounts through narratives of experiences. In this way, we sought to understand how the students perceive the contributions of the subject mentioned above. On the other hand, during text analysis, the dimension of knowing how to be a teacher emerges, closely related to the affections and the experience significance for teacher training. The contributions of the group of participants presented significant findings that showed that future teachers care about their students, create interpersonal bonds that strengthen learning, and in their continuous learning process, they understand that there is another who needs to be accompanied. These findings clearly show that teacher training needs personal mediation and must be sustained by experience.El presente artículo se desprende de una investigación de corte cualitativo con un enfoque narrativo, destinada a indagar acerca del aporte de estudiantes adscriptos a la asignatura Proceso de la Escritura I, del Profesorado de Inglés de la Universidad Nacional de Mar del Plata. Para ello, elaboramos un cuestionario para que lo contestara el grupo de estudiantes que había cursado la asignatura en el año 2019; luego, buscamos relatos de sus experiencias escritos en primera persona. Todo ello con miras a comprender cómo el alumnado percibe el aporte de estudiantes adscriptos en la materia mencionada. Por otro lado, durante el análisis de los textos emerge la dimensión saber-ser docente, lo cual se relaciona estrechamente con el afecto y el valor de la experiencia para la formación de quienes adscriben a la docencia. A partir de los aportes de los participantes, se dieron hallazgos significativos. Entre ellos cabe mencionar la posibilidad de identificar a algunas personas que posiblemente serán docentes en el futuro. Tales personas evidenciaron preocupación por los y las estudiantes, por crear vínculos interpersonales para fortalecer el proceso de aprendizaje, y que en su continuo aprender a ser docentes son conscientes de la existencia de otro o una otra que necesita ser acompañado (a). Estas revelaciones dan cuenta de que la formación docente requiere de la mediación personal y debe de sostenerse en la experiencia.Este artigo é o resultado de uma pesquisa qualitativa com uma abordagem narrativa na qual procuramos inicialmente investigar a contribuição dos estudantes matriculado na disciplina Processo de Redação I do Curso de Formação de Professores de Inglês na Universidade Nacional de Mar del Plata. Para isso, realizamos questionários a todo o grupo de estudantes que haviam cursado a disciplina em 2019. Em seguida, procedemos à busca de relatos em primeira pessoa através de narrativas de experiências. Desta forma, procuramos entender como os estudantes percebem a contribuição dos estudantes matriculados na disciplina acima mencionada. Por outro lado, no decorrer da análise dos textos de campo, emerge a dimensão de saber ser professor, que está intimamente relacionada ao afeto e ao valor da experiência para a formação daqueles que se dedicam ao ensino. As contribuições do grupo de participantes nos apresentaram descobertas significativas que mostraram futuras pessoas docentes que se preocupam por seus e suas estudantes, que criam laços interpessoais que fortalecem a aprendizagem, e que em sua aprendizagem contínua para serem professores sentem que há um outro que precisa ser acompanhado(a). Estas descobertas mostram claramente que o a formação docente precisa de mediação pessoal e deve ser sustentado pela experiência

Molecular characterization of Prototheca strains isolated from Italian dairy herds.

One hundred sixty-one Prototheca spp. strains isolated from composite milk and barn-surrounding environmental samples (bedding, feces, drinking, or washing water, surface swabs) of 24 Italian dairy herds were characterized by genotype-specific PCR analysis. Overall, 97.2% of strains isolated from composite milk samples were characterized as Prototheca zopfii genotype 2, confirming its role as the main mastitis pathogen, whereas Prototheca blaschkeae was only sporadically isolated (2.8%). Regarding environmental sampling, 84.9% of isolates belonged to P. zopfii genotype 2, 13.2% to P. blaschkeae, and 1.9% to P. zopfii genotype 1. The data herein contradict previous hypotheses about the supposed exclusive role of P. zopfii genotype 2 as the causative agent of protothecal mastitis and, on the contrary, confirm the hypothesis that such pathology could be caused by P. blaschkeae in a few instances

Neural development features: Spatio-temporal development of the Caenorhabditis elegans neuronal network

The nematode Caenorhabditis elegans, with information on neural connectivity, three-dimensional position and cell linage provides a unique system for understanding the development of neural networks. Although C. elegans has been widely studied in the past, we present the first statistical study from a developmental perspective, with findings that raise interesting suggestions on the establishment of long-distance connections and network hubs. Here, we analyze the neuro-development for temporal and spatial features, using birth times of neurons and their three-dimensional positions. Comparisons of growth in C. elegans with random spatial network growth highlight two findings relevant to neural network development. First, most neurons which are linked by long-distance connections are born around the same time and early on, suggesting the possibility of early contact or interaction between connected neurons during development. Second, early-born neurons are more highly connected (tendency to form hubs) than later born neurons. This indicates that the longer time frame available to them might underlie high connectivity. Both outcomes are not observed for random connection formation. The study finds that around one-third of electrically coupled long-range connections are late forming, raising the question of what mechanisms are involved in ensuring their accuracy, particularly in light of the extremely invariant connectivity observed in C. elegans. In conclusion, the sequence of neural network development highlights the possibility of early contact or interaction in securing long-distance and high-degree connectivity

Variantes en dos genes candidatos para características de calidad de carne bovina en Argentina

521-532Meat quality is a term used to describe a range of attributes of meat. It is determined by genetic and environmental factors (slaughter age, feeding and pre and post-slaughter management). The current tendency is to study the candidate genes in order to develop molecular markers, which might be used for marker-assisted selection. The objective of this work was to evaluate the effect of polymorphisms (SNP, single nucleotide polymorphisms) in candidate genes for tenderness and fat content in steers fattened in grazing beef production systems of Argentina. Molecular methods were designed to analyze the SNP 4751 (C/T) in bovine capn1 gene (large subunit of u-calpain), associated with tenderness and two polymorphisms (exon 8:G/A and intron 9:C/T) in bovine ppargc1a gene (peroxisome proliferatoractivated receptor gamma coactivator 1-alpha) with effect on fat content in cow milk and fiber type in pigs. Information of Warner-Bratzler shear force and fat content from 60 Brangus and 21 Angus steers was used in association studies. Tenderness of cooked meat was evaluated at 1.7 and 14 days post-mortem. A large proportion of animals were heterozygotes (CT) at SNP 4751. No differences were found between genotypes of this SNP for WBSF. A low frequency of homozygote TT was found at SNP on intron 9 of the ppargc1a gene. This SNP showed no significant effect on WBSF and fat content. Two new SNPs (G/A and T/C) were identified within exon 8 of the ppargc1a gene, by multiple alignment of DNA sequences obtained from 24 bulls of different breeds (Angus, Brangus, Brahman and Braford). One of them (G/A) could be the cause of aminoacid substitution of serine by asparagine at position 364 of the protein. The A allele was not found in Angus. The SNP T/ C is a conservative substitution. It is important that Argentina generate information about factors affecting meat quality for optimizing the production and exportation of high quality beef

Variantes en dos genes candidatos para características de calidad de carne bovina en Argentina

521-532Meat quality is a term used to describe a range of attributes of meat. It is determined by genetic and environmental factors (slaughter age, feeding and pre and post-slaughter management). The current tendency is to study the candidate genes in order to develop molecular markers, which might be used for marker-assisted selection. The objective of this work was to evaluate the effect of polymorphisms (SNP, single nucleotide polymorphisms) in candidate genes for tenderness and fat content in steers fattened in grazing beef production systems of Argentina. Molecular methods were designed to analyze the SNP 4751 (C/T) in bovine capn1 gene (large subunit of u-calpain), associated with tenderness and two polymorphisms (exon 8:G/A and intron 9:C/T) in bovine ppargc1a gene (peroxisome proliferatoractivated receptor gamma coactivator 1-alpha) with effect on fat content in cow milk and fiber type in pigs. Information of Warner-Bratzler shear force and fat content from 60 Brangus and 21 Angus steers was used in association studies. Tenderness of cooked meat was evaluated at 1.7 and 14 days post-mortem. A large proportion of animals were heterozygotes (CT) at SNP 4751. No differences were found between genotypes of this SNP for WBSF. A low frequency of homozygote TT was found at SNP on intron 9 of the ppargc1a gene. This SNP showed no significant effect on WBSF and fat content. Two new SNPs (G/A and T/C) were identified within exon 8 of the ppargc1a gene, by multiple alignment of DNA sequences obtained from 24 bulls of different breeds (Angus, Brangus, Brahman and Braford). One of them (G/A) could be the cause of aminoacid substitution of serine by asparagine at position 364 of the protein. The A allele was not found in Angus. The SNP T/ C is a conservative substitution. It is important that Argentina generate information about factors affecting meat quality for optimizing the production and exportation of high quality beef

A Genome-Wide Analysis of Promoter-Mediated Phenotypic Noise in Escherichia coli

Gene expression is subject to random perturbations that lead to fluctuations in the rate of protein production. As a consequence, for any given protein, genetically identical organisms living in a constant environment will contain different amounts of that particular protein, resulting in different phenotypes. This phenomenon is known as “phenotypic noise.” In bacterial systems, previous studies have shown that, for specific genes, both transcriptional and translational processes affect phenotypic noise. Here, we focus on how the promoter regions of genes affect noise and ask whether levels of promoter-mediated noise are correlated with genes' functional attributes, using data for over 60% of all promoters in Escherichia coli. We find that essential genes and genes with a high degree of evolutionary conservation have promoters that confer low levels of noise. We also find that the level of noise cannot be attributed to the evolutionary time that different genes have spent in the genome of E. coli. In contrast to previous results in eukaryotes, we find no association between promoter-mediated noise and gene expression plasticity. These results are consistent with the hypothesis that, in bacteria, natural selection can act to reduce gene expression noise and that some of this noise is controlled through the sequence of the promoter region alon

Phosphorylated DegU Manipulates Cell Fate Differentiation in the <i>Bacillus subtilis</i> Biofilm<em/>

Cell differentiation is ubiquitous and facilitates division of labor and development. Bacteria are capable of multicellular behaviors that benefit the bacterial community as a whole. A striking example of bacterial differentiation occurs throughout the formation of a biofilm. During Bacillus subtilis biofilm formation, a subpopulation of cells differentiates into a specialized population that synthesizes the exopolysaccharide and the TasA amyloid components of the extracellular matrix. The differentiation process is indirectly controlled by the transcription factor Spo0A that facilitates transcription of the eps and tapA (tasA) operons. DegU is a transcription factor involved in regulating biofilm formation. Here, using a combination of genetics and live single-cell cytological techniques, we define the mechanism of biofilm inhibition at high levels of phosphorylated DegU (DegU∼P) by showing that transcription from the eps and tapA promoter regions is inhibited. Data demonstrating that this is not a direct regulatory event are presented. We demonstrate that DegU∼P controls the frequency with which cells activate transcription from the operons needed for matrix biosynthesis in favor of an off state. Subsequent experimental analysis led us to conclude that DegU∼P functions to increase the level of Spo0A∼P, driving cell fate differentiation toward the terminal developmental process of sporulation