SPOTs: A Novel Mitochondrial Response to Stress at the Outer Mitochondrial Membrane

Mitochondria are essential organelles with multiple functions, including energy production, metabolic homeostasis, programmed cell death, and immune signaling. Because of their diverse functions, mitochondria have complex quality control systems and intricate coordination cellular processes with other organelles. The outer mitochondrial membrane (OMM) is considered the gateway between mitochondria and the rest of the cell and ensures its homeostasis. Although the OMM responses to artificial drugs have been described, whether the OMM responds to natural stress remains unknown.    Infection is an ideal model to study the occurrence of natural OMM stress due to effector proteins secreted by pathogens that affect the OMM. Toxoplasma gondii (Toxoplasma) is of particular interest due to the physical contact between the parasite vacuole and the OMM of the host mitochondria. To address how Toxoplasma affected the OMM, we infected OMM-targeted GFP expressing mammalian cells with Toxoplasma and observed the OMM response by live-cell imaging.   We found that mitochondria in contact with the Toxoplasma vacuole released large structures which we termed “SPOTs” (structures positive for OMM). SPOTs were positive for OMM but lacked markers of the inner mitochondrial membrane (IMM) and matrix and have an average size of 2.6 μm. TgMAF1 (Toxoplasma mitochondrial association factor 1), which is required for the contact between host mitochondria and parasite vacuole, was required for SPOT formation and led to the decrease of the OMM dynamic-related proteins Mitofusin (MFN) 1 and 2 - which mediate a nutritional defense against Toxoplasma by promoting mitochondrial uptake of fatty acids.     SPOT formation induced by TgMAF1 also depends on its binding to the host OMM protein TOM70 (translocase of the outer membrane 70), whose role as a receptor of mitochondrial precursor proteins is impaired by the interaction. TOM70 was beneficial for parasite growth and enabled the interaction between TgMAF1 and the OMM translocase SAM50 (sorting assembly machinery 50 kDa subunit). SAM50 is the only known component of host mitochondrial import machinery with a defined role in bridging the OMM and IMM. In the absence of infection, the genetic ablation of SAM50 or the overexpression of an OMM-targeted protein induced the formation of SPOT structures.   Collectively, these results support a model in which OMM stress is triggered by TgMAF1 which sequesters the mitochondrial precursor receptor TOM70 and interacts with SAM50 during infection. This enables Toxoplasma to hijack a cellular response to OMM stress—the formation of SPOTs—and drive the constitutive shedding of the OMM. The finding of OMM remodeling during infection and infection-independent scenarios sheds light on potential cellular mechanisms that safeguard OMM function

Nonlinear Frequency-Division Multiplexing in the Focusing Regime

Achievable rates of the nonlinear frequency-division multiplexing (NFDM) and wavelength-division multiplexing (WDM) subject to the same power and bandwidth constraints are computed as a function of transmit power in the standard single-mode fiber. NFDM achieves higher rates than WDM.Comment: Invited paper to be presented at The Optical Fiber Communications Conference and Exposition (OFC), March 201

On TI-subgroups and QTI-subgroups of finite groups

summary:Let $G$ be a group. A subgroup $H$ of $G$ is called a TI-subgroup if $H\cap H^g=1$ or $H$ for every $g\in G$ and $H$ is called a QTI-subgroup if $C_G(x) \le N_G(H)$ for any $1\neq x\in H$. In this paper, a finite group in which every nonabelian maximal is a TI-subgroup (QTI-subgroup) is characterized

Digitally reconstructed wall radiographs

Master'sMASTER OF SCIENC

Emerging Applications of III‐Nitride Nanocrystals

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154944/1/pssa201900885_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154944/2/pssa201900885.pd

Octa­kis(2-chloro­benz­yl)di-μ2-hydroxido-di-μ3-oxido-bis­(2-phenyl­acetato)tetra­tin(IV)

The asymmetric unit of the title compound, [Sn4(C7H6Cl)8(C8H7O2)2O2(OH)2], comprises one-half of the centrosymmetric tin(IV) complex. μ3-Oxide and μ2-hydroxide bridges link the four five-coordinate SnIV atoms to generate three fused four-membered Sn—O—Sn—O rings in a ladder-like structure. The two endocyclic Sn atoms each bind to two μ3-oxide anions and a μ2-hydroxide ligand, together with two 2-chloro­benzyl groups. The exocyclic Sn atoms each carry a monodentate phenyl­acetate ligand, two 2-chloro­benzyl groups, and μ3-oxide and μ2-hydroxide ligands. Both types of Sn atoms adopt a distorted trigonal–bipyramidal coordination geometry. The mol­ecular conformation is stabilized by intra­molecular O—H⋯O inter­actions involving the μ2-hydroxide ligands and the C=O group of the phenyl­acetate ligand

Chinese Medicines for Preventing and Treating Radiation-Induced Pulmonary Injury: Still a Long Way to Go

Thoracic radiotherapy is a mainstay of the treatment for lung, esophageal, and breast cancers. Radiation-induced pulmonary injury (RIPI) is a common side effect of thoracic radiotherapy, which may limit the radiotherapy dose and compromise the treatment results. However, the current strategies for RIPI are not satisfactory and may induce other side effects. Chinese medicines (CMs) have been used for more than a thousand years to treat a wide range of diseases, including lung disorders. In this review, we screened the literature from 2007 to 2017 in different online databases, including China National Knowledge Infrastructure (CNKI), Chongqing VIP, Wanfang, and PubMed; summarized the effectiveness of CMs in preventing and treating RIPI; explored the most frequently used drugs; and aimed to provide insights into potential CMs for RIPI. Altogether, CMs attenuated the risk of RIPI with an occurrence rate of 11.37% vs. 27.78% (P < 0.001) compared with the control groups. We also found that CMs (alone and combined with Western medical treatment) for treating RIPI exerted a higher efficacy rate than that of the control groups (78.33% vs. 28.09%, P < 0.001). In the screened literature, 38 CMs were used for the prevention and treatment of RIPI. The top five most frequently used CMs were Astragali Radix (with a frequency of 8.47%), Ophiopogonis Radix (with a frequency of 6.78%), Glycyrrhizae Radix et Rhizome (with a frequency of 5.08%), Paeoniae Radix Rubra (with a frequency of 5.08%), and Prunellae Spica (with a frequency of 5.08%). However, further high-quality investigations in CM source, pharmacological effects and underlying mechanisms, toxicological aspects, and ethical issues are warranted. Taken together, CMs might have a potential role in RIPI prevention and treatment and still have a long way to investigate

Submicron full- color LED pixels for microdisplays and micro- LED main displays

We demonstrate a bottom- up approach to the construction of micro- LEDs as small as 150 nm in lateral dimension. Molecular beam epitaxy (MBE) is used to fabricate such nanostructured LEDs from InGaN, from the blue to red regions of the spectrum, providing a single material set useful for an entire RGB display.We demonstrate a bottom- up approach to the construction of micro- LEDs as small as 150 nm in lateral dimension. Molecular beam epitaxy (MBE) is used to fabricate such nanostructured LEDs from InGaN, from the blue to red regions of the spectrum, providing a single material set useful for an entire RGB display. We then consider collective effects of arrays of such LEDs.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155468/1/jsid899_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155468/2/jsid899.pd