Cytolytic T cells activated by H-2-controlled E molecules cross-react with A molecules

Cell-mediated lymphocytotoxicity was generated in four strain combinations differing only by the cell-surface expression of the class II E molecule controlled by the H-2 complex. The four combinations were: B10.D2(R107) anti-B10.A(3R), B10.A(4R) anti-B10.A(2R), B10.GD anti-B10.D2(R101), and B10.S(7R) anti-B10.S(9R). In all four of these combinations, the stimulator expresses E molecules on the cell surface, while the responder does not. The cytolytic T lymphocytes generated in the B10.D2(R107) anti-B10.A(3R) and B10.A(4R) anti-B10.A(2R) combinations reacted not only with the stimulator but also with strains that do not express cell-surface E molecules, in particular, strains carrying the H-2 ^f and H-2 ^q haplotypes. The cross-reactivity with E-negative strains could be blocked by monoclonal antibodies specific for the A^f or A^q molecules but not by antibodies recognizing determinants on E or class I (K) molecules. The anti-H-2^f cross-reactivity could be inhibited by H-2 ^q cold targets and, reciprocally, the anti-H-2^q reactivity could be blocked by H-2 ^f cold targets. These findings are interpreted as indicating that the cytolytic T lymphocytes stimulated by E molecules can recognize and lyse cells lacking E molecules but expressing A molecules. The observed E-A cross-reactivity supports the notion of structural and functional relatedness between the A and E molecules and suggests a common evolutionary origin of the A- and E-encoding loci.     

Quaternary structure of pyruvate carboxylase from Pseudomonas citronellolis.

Physical-chemical studies of pyruvate carboxylase from Pseudomonas citronellolis demonstrate that the enzyme has an alpha 4 beta 4 structure. The individual polypeptides, alpha (Mr = 65,000) and beta (Mr = 54,000), were separated and isolated by preparative gel electrophoresis. Analysis of the relationship between Coomassie blue staining and protein quantity for each polypeptide indicated that the alpha and beta subunits are present in a 1:1 stoichiometry in the native enzyme. Determinations of the molecular weight of the protein by sedimentation equilibrium (Mr = 454,000), gel filtration analysis (Mr = 510,000), disc gel electrophoresis (Mr = 530,000), and mass measurement from the Scanning Transmission Electron Microscope (Mr = 530,000) are consistent with the proposed alpha 4 beta 4 structure. Disc gel electrophoresis studies revealed that under certain circumstances the enzyme may dissociate to a smaller molecular weight species (Mr = 228,000). This dissociation phenomenon could explain the earlier reported observation of Taylor et al. ((1972) J. Biol. Chem 22, 7388-8390) that the enzyme had a molecular weight of 265,000. Evidence from electron microscopic studies shows that the three-dimensional structure of this enzyme is quite distinct from other species of pyruvate carboxylase. The enzyme does not show the typical rhombic appearance which has been noted for chicken liver, sheep liver, and yeast pyruvate carboxylase.     

Biologic properties of transplantation immune sera. IV. Influence of the course of immunization, dilution and complexing to antigen on enhancing activity of Ig classes.

The influence of the course of immunization on the facilitating-enhancing activity of antibody classes has been studied by passive enhancement of growth of A/JAX sarcomas in CBA and IC mice and of C57BL/6 EL 4 leukemia in BALB/c mice. The influence of dilution of antibodies and complexing to antigens was also studied. During immunization (with several boosters), the enhancing capacity of sera increased together with 7S IgG antibody activity, but showed no correlation with 19S IgM antibody activity. It also was mercaptoethanol resistant. IgG1 to be more enhancing than an equal number of hemagglutinating units of IgG2a. When concentrated on a small amount (10(5)) of target sarcoma I cells, complement-fixing IC anti-A antibodies were even inhibitory on Sa I allografted to IC recipients. Progressive dilutions reversed this situation, IgG1 activity disappearing and IgG2 acquiring enhancing activity. After complexing to corresponding antigens IgG2 also (and immune sera with inhibitory properties) acquired enhancing properties. These results may provide a basis for understanding the discrepancies between the results of several groups of authors studying the class(es) of enhancing anibodies.     

Inhibitory role of TRIP-Br1 oncoprotein in anticancer drug-mediated programmed cell death via mitophagy activation

Chemotherapy has been widely used as a clinical treatment for cancer over the years. However, its effectiveness is limited because of resistance of cancer cells to programmed cell death (PCD) after treatment with anticancer drugs. To elucidate the resistance mechanism, we initially focused on cancer cell-specific mitophagy, an autophagic degradation of damaged mitochondria. This is because mitophagy has been reported to provide cancer cells with high resistance to anticancer drugs. Our data showed that TRIP-Br1 oncoprotein level was greatly increased in the mitochondria of breast cancer cells after treatment with various anticancer drugs including staurosporine (STS), the main focus of this study. STS treatment increased cellular ROS generation in cancer cells, which triggered mitochondrial translocation of TRIP-Br1 from the cytosol via dephosphorylation of TRIP-Br1 by protein phosphatase 2A (PP2A). Up-regulated mitochondrial TRIP-Br1 suppressed cellular ROS levels. In addition, TRIP-Br1 rapidly removed STS-mediated damaged mitochondria by activating mitophagy. It eventually suppressed STS-mediated PCD via degradation of VDACI, TOMM20, and TIMM23 mitochondrial membrane proteins. TRIP-Br1 enhanced mitophagy by increasing expression levels of two crucial lysosomal proteases, cathepsins B and D. In conclusion, TRIP-Br1 can suppress the sensitivity of breast cancer cells to anticancer drugs by activating autophagy/mitophagy, eventually promoting cancer cell survival.     

Transgenerational exposure to marine heatwaves ameliorates the lethal effect on tropical copepods regardless of predation stress

Marine heatwaves (MHWs) are emerging as a severe stressor in marine ecosystems. Extreme warm sea surface temperatures during MHWs often exceed the optimal thermal range for more than one generation of tropical coastal zooplankton. However, it is relatively unknown whether transgenerational plasticity (TGP) to MHWs may shape the offspring''s fitness, particularly in an ecologically relevant context with biotic interactions such as predation stress. We addressed these novel research questions by determining the survival, reproductive success, and grazing rate of the copepod Pseudodiaptomus incisus exposed to MHW and fish predator cues (FPC) for two generations (F1 and F2). The experiment was designed in a full orthogonal manner with 4 treatments in F1 and 16 treatments in F2 generation. In both generations, MHW reduced P. incisus survival, reproductive parameters, and grazing by 10%–62% in MHW, but these parameters increased by 2%–15% with exposure to FPC, particularly at control temperature. F2 reproductive success and grazing rate as indicated by cumulative fecal pellets were reduced by 20%–30% in F1‐MHW, but increased by ~2% in F1‐FPC. Strikingly, MHW exposure reduced 17%–18% survival, but transgenerational exposure to MHWs fully ameliorated its lethal effect and this transgenerational effect was independent of FPC. Increased survival came with a cost of reduced reproductive success, constrained by reduced grazing. The rapid transgenerational MHW acclimation and its associated costs are likely widespread and crucial mechanisms underlying the resilience of coastal tropical zooplankton to MHWs in tropical coastal marine ecosystems.     

Ten simple rules for succeeding as an underrepresented STEM undergraduate

Undergraduate students from underrepresented backgrounds (e.g., Black, Indigenous, and people of color [BIPOC], members of the Deaf community, people with disabilities, members of the 2SLGBTQIA+ community, from low-income backgrounds, or underrepresented genders) continue to face exclusion and marginalization in higher education. In this piece, authored and edited by a diverse group of Science, Technology, Engineering, and Mathematics (STEM) scholars, we present 10 simple rules for succeeding as an underrepresented STEM undergraduate student, illuminating the “hidden curriculum” of STEM specifically as it relates to the underrepresented undergraduate experience. Our rules begin by encouraging students to embrace their own distinct identities and scientific voices and explain how students can overcome challenges unique to underrepresented students throughout their undergraduate degrees. These rules are derived from a combination of our own experiences navigating our undergraduate STEM degrees and the growing body of literature on improving success for underrepresented students.     

SPF: A spatial and functional data analytic approach to cell imaging data

The tumor microenvironment (TME), which characterizes the tumor and its surroundings, plays a critical role in understanding cancer development and progression. Recent advances in imaging techniques enable researchers to study spatial structure of the TME at a single-cell level. Investigating spatial patterns and interactions of cell subtypes within the TME provides useful insights into how cells with different biological purposes behave, which may consequentially impact a subject’s clinical outcomes. We utilize a class of well-known spatial summary statistics, the K-function and its variants, to explore inter-cell dependence as a function of distances between cells. Using techniques from functional data analysis, we introduce an approach to model the association between these summary spatial functions and subject-level outcomes, while controlling for other clinical scalar predictors such as age and disease stage. In particular, we leverage the additive functional Cox regression model (AFCM) to study the nonlinear impact of spatial interaction between tumor and stromal cells on overall survival in patients with non-small cell lung cancer, using multiplex immunohistochemistry (mIHC) data. The applicability of our approach is further validated using a publicly available multiplexed ion beam imaging (MIBI) triple-negative breast cancer dataset.     

Induced production of chitinase to enhance entomotoxicity of Bacillus thuringiensis employing starch industry wastewater as a substrate

Induced production of chitinase during bioconversion of starch industry wastewater (SIW) to Bacillus thuringiensis var. kurstaki HD-1 (Btk) based biopesticides was studied in shake flask as well as in computer-controlled fermentors. SIW was fortified with different concentrations (0%; 0.05%; 0.1%; 0.2%; 0.3% w/v) of colloidal chitin and its consequences were ascertained in terms of Btk growth (total cell count and viable spore count), chitinase, protease and amylase activities and entomotoxicity. At optimum concentration of 0.2% w/v colloidal chitin, the entomotoxicity of fermented broth and suspended pellet was enhanced from 12.4 × 10⁹ (without chitin) to 14.4 × 10⁹ SBU/L and from 18.2 × 10⁹ (without chitin) to 25.1 × 10⁹ SBU/L, respectively. Further, experiments were conducted for Btk growth in a computer-controlled 15 L bioreactor using SIW as a raw material with (0.2% w/v chitin, to induce chitinase) and without fortification of colloidal chitin. It was found that the total cell count, spore count, delta-endotoxin concentration (alkaline solubilised insecticidal crystal proteins), amylase and protease activities were reduced whereas the entomotoxicity and chitinase activity was increased with chitin fortification. The chitinase activity attained a maximum value at 24 h (15 mU/ml) and entomotoxicity of suspended pellet reached highest (26.7 × 10⁹ SBU/L) at 36 h of fermentation with chitin supplementation of SIW. In control (without chitin), the highest value of entomotoxicity of suspended pellet (20.5 × 10⁹ SBU/L) reached at 48 h of fermentation. A quantitative synergistic action of delta-endotoxin concentration, spore concentration and chitinase activity on the entomotoxicity against spruce budworm larvae was observed.     

Affinity-based proteomics reveal cancer-specific networks coordinated by Hsp90

Most cancers are characterized by multiple molecular alterations, but identification of the key proteins involved in these signaling pathways is currently beyond reach. We show that the inhibitor PU-H71 preferentially targets tumor-enriched Hsp90 complexes and affinity captures Hsp90-dependent oncogenic client proteins. We have used PU-H71 affinity capture to design a proteomic approach that, when combined with bioinformatic pathway analysis, identifies dysregulated signaling networks and key oncoproteins in chronic myeloid leukemia. The identified interactome overlaps with the well-characterized altered proteome in this cancer, indicating that this method can provide global insights into the biology of individual tumors, including primary patient specimens. In addition, we show that this approach can be used to identify previously uncharacterized oncoproteins and mechanisms, potentially leading to new targeted therapies. We further show that the abundance of the PU-H71-enriched Hsp90 species, which is not dictated by Hsp90 expression alone, is predictive of the cell's sensitivity to Hsp90 inhibition.