A new role for PGRP-S (Tag7) in immune defense: lymphocyte migration is induced by a chemoattractant complex of Tag7 with Mts1

PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4⁺ and CD8⁺ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response.     

Biochemical mechanism for the inhibition of phenylalanine ammonia-lyase induction in the absence of oxygen in potato tuber tissue

Induction of phenylalanine ammonia-lyase (PAL) in excised potato parenchyma tissue in the presence of light displayed a rigid requirement for oxygen. A     

Process model comparison and transferability across bioreactor scales and modes of operation for a mammalian cell bioprocess

A Monod kinetic model, logistic equation model, and statistical regression model were developed for a Chinese hamster ovary cell bioprocess operated under three different modes of operation (batch, bolus fed‐batch, and continuous fed‐batch) and grown on two different bioreactor scales (3 L bench‐top and 15 L pilot‐scale). The Monod kinetic model was developed for all modes of operation under study and predicted cell density, glucose glutamine, lactate, and ammonia concentrations well for the bioprocess. However, it was computationally demanding due to the large number of parameters necessary to produce a good model fit. The transferability of the Monod kinetic model structure and parameter set across bioreactor scales and modes of operation was investigated and a parameter sensitivity analysis performed. The experimentally determined parameters had the greatest influence on model performance. They changed with scale and mode of operation, but were easily calculated. The remaining parameters, which were fitted using a differential evolutionary algorithm, were not as crucial. Logistic equation and statistical regression models were investigated as alternatives to the Monod kinetic model. They were less computationally intensive to develop due to the absence of a large parameter set. However, modeling of the nutrient and metabolite concentrations proved to be troublesome due to the logistic equation model structure and the inability of both models to incorporate a feed. The complexity, computational load, and effort required for model development has to be balanced with the necessary level of model sophistication when choosing which model type to develop for a particular application. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2013     

Histochemical map of the ectopic expression of the Arabidopsis atExt1 extensin gene in transgenic tobacco

Histochemical analysis of transgenic tobacco plants harboring the promoter of the Arabidopsis extensin gene atExt1 fused to the β-glucuronidase gene coding sequence demonstrated expression of the transgene in stem tissues. The transgene was expressed in cells of the internal and external phloem at the nodal and internodal regions of the older parts of mature stems. In younger parts of the same stem, expression of the transgene was slightly modified: expression was detected in the internal phloem in the internodal areas. In the nodal areas, the phloem tissue and the surrounding parenchyma were stained, demonstrating transgene expression. Expression was also seen in the phloem of the inflorescence; it was non-specific at the junctions of the flowers to the inflorescence. β-glucuronidase (reporter gene) staining was also observed in the pollen grains and at the base of the corolla.     

Promoter regions of the ExtA extensin gene from Brassica napus control activation in response to wounding and tensile stress

Plant Molecular Biology -     

Recovery of morphologically normal transgenic tobacco from hairy roots co-transformed with Agrobacterium rhizogenes and a binary vector plasmid

Summary Co-transformation of tobacco (Nicotiana tabacum) leaf explants with Agrobacterium rhizogenes harbouring pRi1855 and the binary vector pBin19 was achieved at a frequency of 67%. The kanamycin resistant hairy roots were cultured via a callusing phase to regenerate plants which were partially fertile when outcrossed with wild-type pollen. Phenotypic and molecular analysis of the F₁ progeny demonstrated the efficient segregation of the hairy root marker from the kanamycin resistance marker, enabling morphologically normal plants to be recovered which retained the binary vector marker gene. This co-transformation strategy provides a means of introducing non-selectable genes into plants in cases where antibiotic resistance markers are undesirable.     

Sequences responsible for the tissue specific promoter activity of a pea legumin gene in tobacco

Summary Maturing pea cotyledons accumulate large quantities of storage proteins at a specific time in seed development. To examine the sequences responsible for this regulated expression, a series of deletion mutants of the legA major seed storage protein gene were made and transferred to tobacco using the Bin19 disarmed Agrobacterium vector system. A promoter sequence of 97 bp including the CAAT and TATA boxes was insufficient for expression. Expression was first detected in a construct with 549 bp of upstream flanking sequence which contained the the leg box element, a 28 bp conserved sequence found in the legumintype genes of several legume species. Constructs containing-833 and-1203 bp of promoter sequence significantly increased levels of expression. All expressing constructs preserved seed specificity and temporal regulation. The results indicate that promoter sequences between positions-97 and-549 bp are responsible for promoter activity, seed specificity, and temporal regulation of the pea legA gene. Sequences between positions-549 and-1203 bp appear to function as enhancer-like elements, to increase expression.