The TRAPP (Transport protein particle) complex is a conserved protein complex functioning at various steps in vesicle transport. Although yeast has three functionally and structurally distinct forms, ...TRAPPI, II and III, emerging evidence suggests that mammalian TRAPP complex may be different. Mutations in the TRAPP complex subunit 2 (TRAPPC2) cause X-linked spondyloepiphyseal dysplasia tarda, while mutations in the TRAPP complex subunit 9 (TRAPPC9) cause postnatal mental retardation with microcephaly. The structural interplay between these subunits found in mammalian equivalent of TRAPPI and those specific to TRAPPII and TRAPPIII remains largely unknown and we undertook the present study to examine the interaction between these subunits. Here, we reveal that the mammalian equivalent of the TRAPPII complex is structurally distinct from the yeast counterpart thus leading to insight into mechanism of disease.
We analyzed how TRAPPII- or TRAPPIII- specific subunits interact with the six-subunit core complex of TRAPP by co-immunoprecipitation in mammalian cells. TRAPPC2 binds to TRAPPII-specific subunit TRAPPC9, which in turn binds to TRAPPC10. Unexpectedly, TRAPPC2 can also bind to the putative TRAPPIII-specific subunit, TRAPPC8. Endogenous TRAPPC9-positive TRAPPII complex does not contain TRAPPC8, suggesting that TRAPPC2 binds to either TRAPPC9 or TRAPPC8 during the formation of the mammalian equivalents of TRAPPII or TRAPPIII, respectively. Therefore, TRAPPC2 serves as an adaptor for the formation of these complexes. A disease-causing mutation of TRAPPC2, D47Y, failed to interact with either TRAPPC9 or TRAPPC8, suggesting that aspartate 47 in TRAPPC2 is at or near the site of interaction with TRAPPC9 or TRAPPC8, mediating the formation of TRAPPII and/or TRAPPIII. Furthermore, disease-causing deletional mutants of TRAPPC9 all failed to interact with TRAPPC2 and TRAPPC10.
TRAPPC2 serves as an adaptor for the formation of TRAPPII or TRAPPIII in mammalian cells. The mammalian equivalent of TRAPPII is likely different from the yeast TRAPPII structurally.
Fault Tree Analysis (FTA) has realized substantial application for safety engineering; however, the method is not without limitations. Traditional FTA requires substantial time and effort, even for ...single fault assessment, and focuses solely on the probability of event occurrence without considering the severity of consequences. A constrained literature review and examination of functions available in commercial-off-the-shelf FTA software revealed current implementations to lack a structured functional approach to account for severity of intermediate events to a fault as well as severity of fault outcomes. To address this limitation, a novel Consequence Severity-Probability Importance Measure (CSPIM) is proposed as an extension of static FTA. The CSPIM approach is demonstrated through a case study comparing results to those of traditional FTA. Results from a numerical example show that the CSPIM approach effectively prioritizes risky events for safety controls by taking into account both the likelihood and severity of consequences. The CSPIM algorithm calculates a composite risk value and importance of fault tree initiators, revealing those initiators that pose serious risk and should be the focal point for control measures. This approach provides a higher resolution solution than traditional FTA.
Vascular cartilaginous metaplasia and calcification are common in patients with atherosclerosis. However, sources of cells contributing to the development of this complication are currently unknown. ...In this study, we ascertained the origin of cells that give rise to cartilaginous and bony elements in atherosclerotic vessels.
We utilized genetic fate mapping strategies to trace cells of smooth muscle (SM) origin via SM22α-Cre recombinase and Rosa26-LacZ Cre reporter alleles. In animals expressing both transgenes, co-existence within a single cell of β-galactosidase marking cells originally derived from SM cells (SMCs) with osteochondrogenic (Runx2/Cbfa1) or chondrocytic (Sox9, type II collagen) markers, along with simultaneous loss of SM lineage proteins, provides a strong evidence supporting reprogramming of SMCs towards osteochondrogenic or chondrocytic differentiation. Using this technique, we found that vascular SMCs accounted for ~80% of Runx2/Cbfa1-positive cells and almost all of type II collagen-positive cells (~98%) in atherosclerotic vessels of LDLr-/- and ApoE-/- mice. We also assessed contribution from bone marrow (BM)-derived cells via analysing vessels dissected from chimerical ApoE-/- mice transplanted with green fluorescence protein-expressing BM. Marrow-derived cells were found to account for ~20% of Runx2/Cbfa1-positive cells in calcified atherosclerotic vessels of ApoE-/- mice.
Our results are the first to definitively identify cell sources attributable to atherosclerotic intimal calcification. SMCs were found to be a major contributor that reprogrammed its lineage towards osteochondrogenesis. Marrow-derived cells from the circulation also contributed significantly to the early osteochondrogenic differentiation in atherosclerotic vessels.
Inorganic polyphosphate (poly-P), guanosine pentaphosphate (pppGpp) and guanosine tetraphosphate (ppGpp) are ubiquitous in bacteria. These molecules play a variety of important physiological roles ...associated with stress resistance, persistence, and virulence. In the bacterial pathogen Mycobacterium tuberculosis, the identities of the proteins responsible for the metabolism of polyphosphate and (p)ppGpp remain to be fully established. M. tuberculosis encodes two PPX-GppA homologues, Rv0496 (MTB-PPX1) and Rv1026, which share significant sequence similarity with bacterial exopolyphosphatase (PPX) and guanosine pentaphosphate 5'-phosphohydrolase (GPP) proteins. Here we delineate the respective biochemical activities of the Rv0496 and Rv1026 proteins and benchmark these against the activities of the PPX and GPP proteins from Escherichia coli. We demonstrate that Rv0496 functions as an exopolyphosphatase, showing a distinct preference for relatively short-chain poly-P substrates. In contrast, Rv1026 has no detectable exopolyphosphatase activities. Analogous to the E. coli PPX and GPP enzymes, the exopolyphosphatase activities of Rv0496 are inhibited by pppGpp and, to a lesser extent, by ppGpp alarmones, which are produced during the bacterial stringent response. However, neither Rv0496 nor Rv1026 have the ability to hydrolyze pppGpp to ppGpp; a reaction catalyzed by E. coli PPX and GPP. Both the Rv0496 and Rv1026 proteins have modest ATPase and to a lesser extent ADPase activities. pppGpp alarmones inhibit the ATPase activities of Rv1026 and, to a lesser extent, the ATPase activities of Rv0496. We conclude that PPX-GppA family proteins may not possess all the catalytic activities implied by their name and may play distinct biochemical roles involved in polyphosphate and (p)ppGpp metabolic pathways.
Using the Hilbert-Huang transform technique, we investigate the midrange periodicities in solar radio flux at 2800 MHz (F10.7) and sunspot areas (SAs) from February 1, 1947 to September 30, 2016. The ...following prominent results are found: (1) The quasi-periodic oscillations of both data sets are not identical, such as the rotational cycle, the midrange periodicities, and the Schwabe cycle. In particular, the midrange periodicities ranging from 37.9 days to 297.3 days are related to the magnetic Rossby-type waves; (2) The 1.3-year and 1.7-year fluctuations in solar activity indicators are surface manifestations (from photosphere to corona) of magnetic flux changes generated deep inside the Sun; (3) At the timescale of the Schwabe cycle, the complicated phase relationships in the three intervals (1947–1958, 1959–1988, and 1989–2016) agree with the produced periodicities of the magnetic Rossby-type waves. The findings indicate that the magnetic Rossby-type waves are the possible physical mechanism behind the midrange periodicities of solar activity indicators. Moreover, the significant change in the relationship between photospheric and coronal activity took place after the maximum of solar cycle 22 could be interpreted by the magnetic Rossby-type waves.
In this paper, new photometric light curves (LCs) of OT UMa and 2MASS J09251388+6424488 (=NSVS 2497620, hereafter NSVS 2497) in BVRcIc-bands are presented and analyzed by using the 2015 version of ...the Wilson–Devinney (W–D) code. We found that both of them are active contact eclipsing binaries (CEBs) . At the same time, we estimated masses and radii of OT UMa and NSVS 2497 by using our photometric parameters. Then, we also studied the orbital period changes of them by using the O−C method via collecting all available times of light minimum for the first time, and new linear ephemerides are obtained. Besides, the formation and evolution of these two targets are discussed, and we thought that OT UMa could be undergoing thermal relaxation oscillations.
•The new light curves of OT UMa and NSVS 2497620 in B, V, R and I-bands are obtained and analyzed.•We obtained new photometric solutions and analyzed the changes of the orbital period for these two targets.•It is found that both of them are active contact eclipsing binaries.•OT Uma is possible undergoing thermal relaxation oscillations.
Plastic waste accumulation in marine environments has complex, unintended impacts on ecology that cross levels of community organization. To measure succession in polyolefin-colonizing marine ...bacterial communities, an
time-series experiment was conducted in the oligotrophic coastal waters of the Bermuda Platform. Our goals were to identify polyolefin colonizing taxa and isolate bacterial cultures for future studies of the biochemistry of microbe-plastic interactions. HDPE, LDPE, PP, and glass coupons were incubated in surface seawater for 11 weeks and sampled at two-week intervals. 16S rDNA sequencing and ATR-FTIR/HIM were used to assess biofilm community structure and chemical changes in polymer surfaces. The dominant colonizing taxa were previously reported cosmopolitan colonizers of surfaces in marine environments, which were highly similar among the different plastic types. However, significant differences in rare community composition were observed between plastic types, potentially indicating specific interactions based on surface chemistry. Unexpectedly, a major transition in community composition occurred in all material treatments between days 42 and 56 (
< 0.01). Before the transition, Alteromonadaceae, Marinomonadaceae, Saccharospirillaceae, Vibrionaceae, Thalassospiraceae, and Flavobacteriaceae were the dominant colonizers. Following the transition, the relative abundance of these taxa declined, while Hyphomonadaceae, Rhodobacteraceae and Saprospiraceae increased. Over the course of the incubation, 8,641 colonizing taxa were observed, of which 25 were significantly enriched on specific polyolefins. Seven enriched taxa from families known to include hydrocarbon degraders (Hyphomonadaceae, Parvularculaceae and Rhodobacteraceae) and one n-alkane degrader (
sp.). The ASVs that exhibited associations with specific polyolefins are targets of ongoing investigations aimed at retrieving plastic-degrading microbes in culture.
Regulatory T (Treg) cells are essential for immune tolerance of embryo implantation, and insufficient Treg cells are implicated in early pregnancy loss. An abortion-prone mouse model was used to ...evaluate the utility of IL-2 complexed with JES6-1 anti–IL-2 antibody (IL-2/JES6-1) to boost uterine Treg cells and improve reproductive success. IL-2/JES6-1, but not IL-2/IgG control, administered in the periconception phase to CBA/J females mated with DBA/2 males elicited a greater than twofold increase in the proportion of CD4+ T cells expressing forkhead box P3 (FOXP3), and an increase in the ratio of FOXP3+ Treg cells/FOXP3– T conventional cells, in the uterus and its draining lymph nodes at embryo implantation that was sustained into midgestation. An attenuated phenotype was evident in both thymic-derived and peripheral Treg cells with elevated cytotoxic T-lymphocyte antigen-4, CD25, and FOXP3, indicating improved suppressive function, as well as increased proliferative marker Ki-67. IL-2/JES6-1 treatment reduced fetal loss from 31% to 10%, but this was accompanied by a 6% reduction in late gestation fetal weight, despite comparable placental size and architecture. Similar effects of IL-2/JES6-1 on Treg cells and fetal growth were seen in CBA/J females with healthy pregnancies sired by BALB/c males. These findings show that expanding the uterine Treg cell pool through targeting IL-2 signaling is a strategy worthy of further investigation for mitigating immune-mediated fetal loss.
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Theabrownin (TB), a natural compound present in the fresh leaves of green tea, is a potential antitumor agent. However, so far whether and how TB affects glioma is unclear. In this study, we ...investigated the effect of TB on astroglioma and oligodendroglioma cells. Surprisingly, TB significantly reduced the viabilities of HOG and U251 cells in a dose-dependent manner, which was accompanied by the upregulation of active-Casp-3, Bax, and PTEN; meanwhile, the antiapoptotic gene Bcl-2 was downregulated. In addition, TB treatment induced cell cycle arrest at the G1 and G2/M phases in HOG and U251 cells, respectively. TB treatment caused the downregulating of c-myc, cyclin D, CDK2, and CDK4 and upregulating of p21 and p27 in the HOG cell, while TB increased P53, p21, and p27 levels and decreased the levels of cell cycle regulator proteins such as CDK and cyclin A/B in the U251 cells. Therefore, the c-myc- and P53-related mechanisms were proposed for cell cycle arrest in these two glioma cell lines, respectively. Overall, our findings indicated that TB could be a novel candidate drug for the treatment of gliomas.
Agents stabilizing G-quadruplexes have the potential to interfere with telomere replication by blocking the elongation step catalysed by telomerase or telomerase-independent mechanism and could ...therefore act as antitumor agents. In this study, we found that quindoline derivatives interacted preferentially with intramolecular G-quadruplex structures and were novel potent telomerase inhibitors. Treatment with quindoline derivatives reproducibly inhibited telomerase activity in human leukemia K562 cells and colon cancer SW620 cells. N'-(10H-Indolo 3,2-b quinolin-11-yl)-N, N-dimethyl-propane-1,3-diamine (SYUIQ-5), (one of quindoline derivatives), when added to K562 and SW620 cell culture at nonacute cytotoxic concentrations, increased time of population doublings of K562 and SW620 cells, induced a marked cessation in cell growth and cellular senescence phenotype after 35 and 18 days, respectively. Growth cessation was accompanied by a shortening of telomere length, and induction of p16, p21 and p27 protein expression. However, another compound SYUIQ-7 with greater IC(50) for telomerase had no obvious cellular effect in nonacute cytotoxic concentrations. These results indicate that quindoline derivatives as novel potent G-quadruplex interactive agents induce senescence and telomere shortening in cancer cells and therefore are promising agents for cancer treatment.
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