[SWI+], the Prion Formed by the Chromatin Remodeling Factor Swi1, Is Highly Sensitive to Alterations in Hsp70 Chaperone System Activity

The yeast prion [SWI+], formed of heritable amyloid aggregates of the Swi1 protein, results in a partial loss of function of the SWI/SNF chromatin-remodeling complex, required for the regulation of a diverse set of genes. Our genetic analysis revealed that [SWI+] propagation is highly dependent upon the action of members of the Hsp70 molecular chaperone system, specifically the Hsp70 Ssa, two of its J-protein co-chaperones, Sis1 and Ydj1, and the nucleotide exchange factors of the Hsp110 family (Sse1/2). Notably, while all yeast prions tested thus far require Sis1, [SWI+] is the only one known to require the activity of Ydj1, the most abundant J-protein in yeast. The C-terminal region of Ydj1, which contains the client protein interaction domain, is required for [SWI+] propagation. However, Ydj1 is not unique in this regard, as another, closely related J-protein, Apj1, can substitute for it when expressed at a level approaching that of Ydj1. While dependent upon Ydj1 and Sis1 for propagation, [SWI+] is also highly sensitive to overexpression of both J-proteins. However, this increased prion-loss requires only the highly conserved 70 amino acid J-domain, which serves to stimulate the ATPase activity of Hsp70 and thus to stabilize its interaction with client protein. Overexpression of the J-domain from Sis1, Ydj1, or Apj1 is sufficient to destabilize [SWI+]. In addition, [SWI+] is lost upon overexpression of Sse nucleotide exchange factors, which act to destabilize Hsp70's interaction with client proteins. Given the plethora of genes affected by the activity of the SWI/SNF chromatin-remodeling complex, it is possible that this sensitivity of [SWI+] to the activity of Hsp70 chaperone machinery may serve a regulatory role, keeping this prion in an easily-lost, meta-stable state. Such sensitivity may provide a means to reach an optimal balance of phenotypic diversity within a cell population to better adapt to stressful environments

An enigma in the genetic responses of plants to salt stresses

Soil salinity is one of the main factors restricting crop production throughout the world. Various salt tolerance traits and the genes controlling these traits are responsible for coping with salinity stress in plants. These coping mechanisms include osmotic tolerance, ion exclusion, and tissue tolerance. Plants exposed to salinity stress sense the stress conditions, convey specific stimuli signals, and initiate responses against stress through the activation of tolerance mechanisms that include multiple genes and pathways. Advances in our understanding of the genetic responses of plants to salinity and their connections with yield improvement are essential for attaining sustainable agriculture. Although a wide range of studies have been conducted that demonstrate genetic variations in response to salinity stress, numerous questions need to be answered to fully understand plant tolerance to salt stress. This chapter provides an overview of previous studies on the genetic control of salinity stress in plants, including signaling, tolerance mechanisms, and the genes, pathways, and epigenetic regulators necessary for plant salinity tolerance

Buffer rod design for measurement of specific gravity in the processing of industrial food batters

A low cost perspex buffer rod design for the measurement of specific gravity during the processing of industrial food batters is reported. Operation was conducted in pulsed mode using a 2.25MHz, 15mm diameter transducer and the intensity and an analytic calibration curve relating buffer rod output to specific gravity is obtained. The probe design may have application to other similar mixtures or industrial sludges in which similar material properties are observed

Immunohistochemical study of TGF-β, PDL-1, and IL-10 in patients with Toxoplasma gondii

The aim of this study to evaluate the expression of Programmed cell death-1 (PD-1), TGF- ß, and IL-10 in placental tissue of aborted women and the correlation with Toxoplasma.gondii (T. gondii) and the correlation of these cytokines with each other and with toxoplasmosis, during an abortion. The placental tissue samples have been processed and used for immunohistochemistry to study the expression of PDL-1, IL-10, and TGF-β. There was an increase in expression of TGF-β, PDL-1, and IL-10 in the placental tissue of aborted women infected with T.gondii, The results of the study showed that the residence of pregnant women in an urban area or rural has no relation with Toxoplasmosis infection (P&gt;0.05), Age shows a significant correlation with Toxoplasmosis, the risk of infection increased with age (P&lt;0.05). The number of recurrent abortions has no significant correlation effect in toxoplasmosis infection and abortion between the positive and control groups (P&gt;0.05), Placental expression of PDL-1, IL-10, and TGF-β show significant correlation during infection with toxoplasmosis (P&lt;0.05).</jats:p