Control of T cell function by positive and negative regulators

T cells are an essential element of the body's immune system. Engagement of the T cell receptor is responsible for initiating the signaling events that can activate, inactivate, or eliminate T cells, depending on the magnitude and duration of the signal. Control of T cell signaling occurs through both positive and negative regulation, as well as through the actions of molecular scaffolds that contribute to the formation of signaling complexes. The T Cell Signal Transduction Pathway at the STKE Connections Maps highlights the molecular components that are responsible for T cell activation. Understanding the mechanisms that regulate T cell responsiveness will aid in the development of therapeutic agents to treat infection, cancer, and autoimmune disease and immune deficiency.     

Salt Tolerance of Canola in Relation to Accumulation and Xylem Transportation of Cations

ABSTRACT

This study was conducted in a greenhouse to evaluate the root and shoot response of canola (Brassica napus L.) to salt-stress conditions and the remobilization, deposition, and input rate of sodium (Na), potassium (K), and magnesium (Mg) at different salinity levels using two canola cultivars. A salt-tolerant (‘Kristina’) cultivar and a salt-sensitive (‘Hyola 308’) cultivar were grown in nutrient solutions with 0, 50, 100, 150, and 200 mol m^?3 NaCl for 7 d. The plants were harvested after 6, 12, 18, and 24 h and 3 and 7 d after salt treatment. The results indicated that increasing salinity significantly decreased shoot and root weights 7 d after treatment. Also, K content and K-Na selectivity decreased in both cultivars, but the changes in ‘Hyola 308’ were greater than in ‘Kristina.’ Electrolyte leakage was increased significantly by salinity, and cell-membrane stability of ‘Hyola 308’ was damaged more than that of ‘Kristina’. Sodium import, transport, and deposition was increased by salinity concentration but remobilization was decreased. The K and Mg import, deposition, and remobilization were also decreased. From this experiment we can conclude that greater K and Mg remobilization in ‘Kristina’ could be a mechanism of salt tolerance in canola.     

INTERACTIVE EFFECTS OF SALINITY AND PHOSPHORUS NUTRITION ON PHYSIOLOGICAL RESPONSES OF TWO BARLEY SPECIES

Salinity is one of the most important agricultural problems in Iran. The effect of different levels of salinity and phosphorus on shoot length, root and shoot fresh and dry weight, nutrient elements (sodium (Na⁺), potassium (K⁺), phosphorus (P) and chloride (Cl^?), proline and soluble sugar contents of barley were investigated. Two cultivars of barley, Hordeum murinum (wild resistant germplasm) and Hordeum vulgar, variety Afzal were treated in vegetative stage under hydroponics condition in a factorial arrangement based on completely randomized block (CRB) design with four levels of salinity [0, 100, 200 and 300 mM sodium chloride (NaCl)] and three levels of phosphorus (15, 30 and 55 μm L^?1) with three replications. By increasing salinity, all the measured parameters, except sodium (Na⁺) content were reduced. Furthermore, with increased in phosphorus levels from 15 to 55 μm, Na⁺ content of the plant shoots decreased, but length, fresh and dry weights of roots and shoots and K⁺, P, Cl^?, proline, and soluble sugars content of the shoots increased. The results indicated that accumulation of mineral ions for osmotic adjustment and restriction of Na⁺ accumulation in shoots were involved in phosphorus enhancement of the salt tolerance of barley. Thus, it seems that in saline soils, where there is no possibility for soil leaching and amending, application of phosphorus fertilizers can lead to a satisfactory growth and production in barely yield.     

What is the ocean: A sea‐change in our perceptions and values?

1. Throughout human history, the ocean has occupied myriad cultural meanings, mythologies and practices, which were often founded on a notion of the sea as being so large and ‘powerful’ as to be immune to human impacts. These conceptions were grounded in observations from the surface or shoreline, and in periods when human activities in the ocean were more technologically and spatially limited than they are today.
2. Advancements in science and technology have significantly altered how humans interact with and access the ocean, allowing exploration and exploitation of ocean areas and processes that were previously incomprehensible. This new capacity to understand and extract from the ocean might be expected to profoundly alter human relationships to it and conceptions of it.
3. As public support and engagement with marine conservation and ‘blue economies’ stem from value and belief systems, future marine management will benefit from recognizing our historical marine relationships as context for changes in understanding, use, and the increasing environmental degradation faced by the ocean. This review focuses on perspectives of the ocean that have been held historically and queries their future persistence at this potential turning point in our relationship with the ocean.

     

The Profitability of Strip Plantations: A Case Study on Two Social Forest Divisions in Bangladesh

ABSTRACT

Forest concessions are currently in a state of flux. Despite mitigated results in some regions, they are still hailed as the path to sustainable forest management on other continents. Using geographical, economic, and political viewpoints, this article offers a multidisciplinary perspective to account for this apparent contradiction. The authors conclude that although political actors continue to support or criticize them by using a range of historical, contextual, and ideological associations, large-scale forest concessions can be theoretically justified from an economic and geographical viewpoint.     

The effect of lateral heel studs on the kinematics of the equine digit while cantering on grass

This study aimed to assess the effect of lateral heel studs on foot-ground interaction in the horse by quantifying foot slip during stance whilst cantering on a grass surface. It was hypothesised that using studs would decrease foot slip distance on the ground conditions tested. Nine horses were ridden with and without a stud placed laterally in the shoe of each of the 4 feet. High speed video-analysis was used to track hoof markers and to provide data quantifying foot slip distance, slip duration and stance duration. Using studs resulted in a significant decrease in foot slip distance in all four limbs (all P values<0.004). The magnitude of the difference in slip distance with and without studs was greatest in the trailing limbs. The results supported the hypothesis that using studs will decrease foot slip distance in horses cantering on a grass surface, and additionally, highlights that stud efficacy may vary between limbs. The decrease in slip distance with studs demonstrated increased traction and a more stable foot-ground interaction, although this may cause a concomitant increase in the required energy dissipation, either within the limb or via surface deformation. The effect of repetitive usage of studs in the aetiology of musculoskeletal conditions should therefore be investigated further.     

Use of pooled samples for the detection of Salmonella in feces by polymerase chain reaction.

Many epidemiological studies of Salmonella rely on conventional bacteriological culture methods to detect Salmonella in fecal samples. These culture-based methods are inefficient for epidemiological studies in populations with a low prevalence of Salmonella. The objective of this study was to optimize a protocol that uses pooled Salmonella enrichment broth cultures of bovine feces and polymerase chain reaction (PCR) for the detection of the invA gene of Salmonella in feces. In one field trial, 196 animals were sampled, and all samples were tested by culture, invA PCR on individual samples, invA PCR on pools of 5 samples, and BAX PCR on individual samples. All assays showed a high agreement on individual samples (kappa > or = 0.75). The invA PCR was run on each of 40 pools and detected 19 of 22 culture-positive pools. In another field trial, 152 samples were taken from 4 dairies, and the invA PCR was performed on pools of 5 samples in addition to bacteriological culture of individual samples. Salmonella was detected in 5 of the 32 pools (7 total positive samples) by both PCR and culture. One pool was PCR-positive but culture-negative. Pooling did not dramatically affect the performance of the invA PCR; most of the culture-positive samples were detected, including all of the samples when there were 4 or more Salmonella colonies on the agar plate. Based on these field trials, invA PCR on pooled samples appears to be an efficient method of Salmonella detection as long as Salmonella loads are not extremely low.