Basic helix-loop-helix pioneer factors interact with the histone octamer to invade nucleosomes and generate nucleosome-depleted regions.

Nucleosomes drastically limit transcription factor (TF) occupancy, while pioneer transcription factors (PFs) somehow circumvent this nucleosome barrier. In this study, we compare nucleosome binding of two conserved S. cerevisiae basic helix-loop-helix (bHLH) TFs, Cbf1 and Pho4. A cryo-EM structure of Cbf1 in complex with the nucleosome reveals that the Cbf1 HLH region can electrostatically interact with exposed histone residues within a partially unwrapped nucleosome. Single-molecule fluorescence studies show that the Cbf1 HLH region facilitates efficient nucleosome invasion by slowing its dissociation rate relative to DNA through interactions with histones, whereas the Pho4 HLH region does not. In vivo studies show that this enhanced binding provided by the Cbf1 HLH region enables nucleosome invasion and ensuing repositioning. These structural, single-molecule, and in vivo studies reveal the mechanistic basis of dissociation rate compensation by PFs and how this translates to facilitating chromatin opening inside cells.

Crystal Structure of the LSD1/CoREST Histone Demethylase Bound to Its Nucleosome Substrate.

LSD1 (lysine specific demethylase; also known as KDM1A), the first histone demethylase discovered, regulates cell-fate determination and is overexpressed in multiple cancers. LSD1 demethylates histone H3 Lys4, an epigenetic mark for active genes, but requires the CoREST repressor to act on nucleosome substrates. To understand how an accessory subunit (CoREST) enables a chromatin enzyme (LSD1) to function on a nucleosome and not just histones, we have determined the crystal structure of the LSD1/CoREST complex bound to a 191-bp nucleosome. We find that the LSD1 catalytic domain binds extranucleosomal DNA and is unexpectedly positioned 100 Å away from the nucleosome core. CoREST makes critical contacts with both histone and DNA components of the nucleosome, explaining its essential function in demethylating nucleosome substrates. Our studies also show that the LSD1(K661A) frequently used as a catalytically inactive mutant in vivo (based on in vitro peptide studies) actually retains substantial H3K4 demethylase activity on nucleosome substrates.

Intensive Ambulance-Delivered Blood-Pressure Reduction in Hyperacute Stroke.

BACKGROUND: Treatment of acute stroke, before a distinction can be made between ischemic and hemorrhagic types, is challenging. Whether very early blood-pressure control in the ambulance improves outcomes among patients with undifferentiated acute stroke is uncertain. METHODS: We randomly assigned patients with suspected acute stroke that caused a motor deficit and with elevated systolic blood pressure (≥150 mm Hg), who were assessed in the ambulance within 2 hours after the onset of symptoms, to receive immediate treatment to lower the systolic blood pressure (target range, 130 to 140 mm Hg) (intervention group) or usual blood-pressure management (usual-care group). The primary efficacy outcome was functional status as assessed by the score on the modified Rankin scale (range, 0 [no symptoms] to 6 [death]) at 90 days after randomization. The primary safety outcome was any serious adverse event. RESULTS: A total of 2404 patients (mean age, 70 years) in China underwent randomization and provided consent for the trial: 1205 in the intervention group and 1199 in the usual-care group. The median time between symptom onset and randomization was 61 minutes (interquartile range, 41 to 93), and the mean blood pressure at randomization was 178/98 mm Hg. Stroke was subsequently confirmed by imaging in 2240 patients, of whom 1041 (46.5%) had a hemorrhagic stroke. At the time of patients' arrival at the hospital, the mean systolic blood pressure in the intervention group was 159 mm Hg, as compared with 170 mm Hg in the usual-care group. Overall, there was no difference in functional outcome between the two groups (common odds ratio, 1.00; 95% confidence interval [CI], 0.87 to 1.15), and the incidence of serious adverse events was similar in the two groups. Prehospital reduction of blood pressure was associated with a decrease in the odds of a poor functional outcome among patients with hemorrhagic stroke (common odds ratio, 0.75; 95% CI, 0.60 to 0.92) but an increase among patients with cerebral ischemia (common odds ratio, 1.30; 95% CI, 1.06 to 1.60). CONCLUSIONS: In this trial, prehospital blood-pressure reduction did not improve functional outcomes in a cohort of patients with undifferentiated acute stroke, of whom 46.5% subsequently received a diagnosis of hemorrhagic stroke. (Funded by the National Health and Medical Research Council of Australia and others; INTERACT4 ClinicalTrials.gov number, NCT03790800; Chinese Trial Registry number, ChiCTR1900020534.).

Hierarchical assembly of the MLL1 core complex regulates H3K4 methylation and is dependent on temperature and component concentration.

Enzymes of the mixed lineage leukemia (MLL) family of histone H3 lysine 4 (H3K4) methyltransferases are critical for cellular differentiation and development and are regulated by interaction with a conserved subcomplex consisting of WDR5, RbBP5, Ash2L, and DPY30. While pairwise interactions between complex subunits have been determined, the mechanisms regulating holocomplex assembly are unknown. In this investigation, we systematically characterized the biophysical properties of a reconstituted human MLL1 core complex and found that the MLL1-WDR5 heterodimer interacts with the RbBP5-Ash2L-DPY30 subcomplex in a hierarchical assembly pathway that is highly dependent on concentration and temperature. Surprisingly, we found that the disassembled state is favored at physiological temperature, where the enzyme rapidly becomes irreversibly inactivated, likely because of complex components becoming trapped in nonproductive conformations. Increased protein concentration partially overcomes this thermodynamic barrier for complex assembly, suggesting a potential regulatory mechanism for spatiotemporal control of H3K4 methylation. Together, these results are consistent with the hypothesis that regulated assembly of the MLL1 core complex underlies an important mechanism for establishing different H3K4 methylation states in mammalian genomes.

Clinical outcome and peripheral immune profile of myasthenic crisis with omicron infections: A prospective cohort study.

The impact of Omicron infections on the clinical outcome and immune responses of myasthenia gravis (MG) remained largely unknown. From a prospective multicenter MG cohort (n = 189) with 197 myasthenic crisis (MC), we finally included 41 independent MG patients to classify into two groups: the Omicron Group (n = 13) and the Control Group (n = 28). In this matched cohort study, all-cause mortality was 7.69% (1/13) in Omicron Group and 14.29% (4/28) in Control Group. A higher proportion of elevated serum IL-6 was identified in the Omicron Group (88.89% vs 52.38%, P = 0.049). In addition, the proportions of CD3+CD8+T in lymphocytes and Tregs in CD3+CD4+ T cells were significantly elevated in the Omicron Group (both P = 0.0101). After treatment, the Omicron Group exhibited a marked improvement in MG-ADL score (P = 0.026) and MG-QoL-15 (P = 0.0357). MCs with Omicron infections were associated with elevated serum IL-6 and CD3+CD8+T response. These patients tended to present a better therapeutic response after fast-acting therapies and anti-IL-6 treatment.

Elevational variation in metabolic rate, feeding capacity and their associations in the Asiatic toad Bufo gargarizans.

Foraging behavior is known to place demands on the metabolic characteristics of anurans. Active foragers feeding on sedentary prey typically have high aerobic capacity and low anaerobic capacity, whereas sit-and-wait foragers feeding on active and mobile prey have the opposite pattern. Thus, the energetic demands of foraging may influence their metabolic adaptations to harsh environments, such as high elevations. Anurans that engage in active foraging have been found to increase maximum metabolic rate (MMR) and aerobic scope (AS, the difference between MMR and resting metabolic rate, RMR) at high elevations. However, data are lacking in amphibian ambush foragers. In this study, we examined the RMR, MMR, AS, and feeding capacity of a sit-and-wait forager ─the Asiatic toad (Bufo gargarizans), from two populations that are in close geographic proximity but differ by 1350 m in elevation. Our results show that there is no elevational variation in RMR and feeding capacity in either males or females. However, there are sex-specific variations in MMR and AS along an elevational gradient; females from high elevations have lower MMR and smaller net AS than their counterparts from low elevations while males maintain similar MMR and net AS across elevations. Furthermore, aerobic performances do not appear to be associated with feeding capacity at either the individual or population level. Our results support the hypothesis that sit-and-wait foragers may not increase their aerobic capacity as a strategy in hypoxic and low food availability environments and the role of sex in these adaptive adjustments should not be overlooked.

Impact of dysautonomic symptom burden on the quality of life in Neuromyelitis optica spectrum disorder patients.

BACKGROUND: This study aimed to investigate the clinical risk factors of dysautonomic symptom burden in neuromyelitis optica spectrum disorder (NMOSD) and its impact on patients' quality of life. METHODS: A total of 63 NMOSD patients and healthy controls were enrolled. All participants completed the Composite Autonomic Symptom Score 31 (COMPASS-31) to screen for symptoms of autonomic dysfunction. A comprehensive clinical evaluation was performed on NMOSD patients, such as disease characteristics and composite evaluations of life status, including quality of life, anxiety/depression, sleep, and fatigue. Correlated factors of dysautonomic symptoms and quality of life were analyzed. RESULTS: The score of COMPASS-31 in the NMOSD group was 17.2 ± 10.3, significantly higher than that in healthy controls (P = 0.002). In NMOSD patients, the higher COMPASS-31 score was correlated with more attacks (r = 0.49, P < 0.001), longer disease duration (r = 0.52, P < 0.001), severer disability (r = 0.50, P < 0.001), more thoracic cord lesions (r = 0.29, P = 0.02), more total spinal cord lesions (r = 0.35, P = 0.005), severer anxiety (r = 0.55, P < 0.001), severer depression (r = 0.48, P < 0.001), severer sleep disturbances (r = 0.59, P < 0.001), and severer fatigue (r = 0.56, P < 0.001). The disability, total spinal cord lesions, and fatigue were revealed to be independently associated factors. Further analysis revealed that the COMPASS-31 score was independently correlated with scores of all the domains of patients' quality of life scale (P < 0.05). CONCLUSIONS: Dysautonomic symptom burden is correlated with decreased quality of life and certain clinical characteristics such as disability, the burden of spinal cord lesions, and fatigue in NMOSD patients. Investigation and proper management of autonomic dysfunction may help to improve the quality of life in patients with NMOSD.

Anticancer Activity of Methyl Protodioscin against Prostate Cancer by Modulation of Cholesterol-Associated MAPK Signaling Pathway via FOXO1 Induction.

Methyl protodioscin (MPD), a furostanol saponin found in the rhizomes of Dioscoreaceae, has lipid-lowering and broad anticancer properties. However, the efficacy of MPD in treating prostate cancer remains unexplored. Therefore, the present study aimed to evaluate the anticancer activity and action mechanism of MPD in prostate cancer. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), wound healing, transwell, and flow cytometer assays revealed that MPD suppressed proliferation, migration, cell cycle, and invasion and induced apoptosis of DU145 cells. Mechanistically, MPD decreased cholesterol concentration in the cholesterol oxidase, peroxidase and 4-aminoantipyrine phenol (COD-PAP) assay, disrupting the lipid rafts as detected using immunofluorescence and immunoblot analyses after sucrose density gradient centrifugation. Further, it reduced the associated mitogen-activated protein kinase (MAPK) signaling pathway protein P-extracellular regulated protein kinase (ERK), detected using immunoblot analysis. Forkhead box O (FOXO)1, a tumor suppressor and critical factor controlling cholesterol metabolism, was predicted to be a direct target of MPD and induced by MPD. Notably, in vivo studies demonstrated that MPD significantly reduced tumor size, suppressed cholesterol concentration and the MAPK signaling pathway, and induced FOXO1 expression and apoptosis in tumor tissue in a subcutaneous mouse model. These results suggest that MPD displays anti-prostate cancer activity by inducing FOXO1 protein, reducing cholesterol concentration, and disrupting lipid rafts. Consequently, the reduced MAPK signaling pathway suppresses proliferation, migration, invasion, and cell cycle and induces apoptosis of prostate cancer cells.

Biosurfactant from Pseudomonas fragi enhances the competitive advantage of Pseudomonas but reduces the overall spoilage ability of the microbial community in chilled meat.

Biosurfactants from Pseudomonas spp. have been reported to exhibit antibacterial and anti-adhesive properties, but their role during meat spoilage remains unclear. In this study, the biosurfactant was isolated from an isolate of Pseudomonas fragi with strong spoilage potential, and its surface tension and emulsification ability were determined. The chemical and microbial characteristics of the biosurfactant-treated meat samples were periodically analyzed. The results demonstrated that the biosurfactant produced by P. fragi could reduce surface tension and showed good emulsification properties. For the in situ spoilage trials, biosurfactant from P. fragi changed the microbial diversity on meat, helping Pseudomonas establish a dominant position in the population. However, biosurfactant treatment caused chicken meat to exhibit a weaker spoilage state, as indicated by the growth of psychrophilic microorganisms, total volatile basic nitrogen (TVBN) and meat color. These results provide practical information for understanding the role of P. fragi biosurfactant during chilled meat storage.

Efficacy and safety of totally laparoscopic gastrectomy with uncut Roux-en-Y for gastric cancer: a dual-center retrospective study.

BACKGROUND: Uncut Roux-en-Y (URY) effectively alleviates the prevalent complexities connected with RY, such as Roux-en-Y stasis syndrome (RSS). Nevertheless, for gastric cancer (GC) patients, it is still controversial whether URY has an impact on long-term prognosis and whether it has fewer afferent loop recanalization. Therefore, compare whether URY and RY have differences in prognosis and long-term complications of GC patients undergoing totally laparoscopic gastrectomy (TLG). METHODS: We analyzed the data of patients who underwent TLG combined with digestive tract reconstruction from dual-center between 2016 and 2022. Only patients undergoing URY and RY were selected for analysis. Relapse-free survival (RFS) and overall survival (OS) were estimated. Bias between the groups was reduced by propensity score matching (PSM). The Cox proportional hazard regression model was used to further analyze the influence of URY on prognosis. RESULTS: Two hundred forty two GC patients were enrolled. The URY had significantly shorter operation time, liquid food intake time, and in-hospital stays than the RY (P < 0.001). The URY had fewer long-term and short-term postoperative complications than the RY, especially with regard to RSS, reflux esophagitis, and reflux gastritis. The 3-year and 5-year OS of the URY group and the RY group before PSM: 87.5% vs. 65.6% (P < 0.001) and 81.4% vs. 61.7% (P = 0.001). PSM and Cox multivariate analysis confirmed that compared to RY, URY can improve the short-term and long-term prognosis of GC patients. CONCLUSION: TLG combined with URY for GC, especially for advanced, older, and poorly differentiated patients, may promote postoperative recovery and improve long-term prognosis.

HS-SPME coupled with GC-MS for elucidating differences between the volatile components in wild and cultivated Atractylodes chinensis.

INTRODUCTION: Atractylodes chinensis is a Chinese herb that is used in traditional medicine; it contains volatile components that have enormous potential for pharmaceutical, food, and cosmetic applications. The destruction of wild resources demands significant improvement in the quality of artificial cultivation of Atractylodes chinensis. However, little is known about the compositional differences in the volatile substances derived from the wild and cultivated varieties of Atractylodes chinensis. OBJECTIVES: We aimed to evaluate the specific components of Atractylodes chinensis and analyse the similarities and differences between the volatile components and metabolic pathways in the wild and cultivated varieties. MATERIAL AND METHODS: Metabolomic analysis using gas chromatography-mass spectrometry (GC-MS) was employed following the extraction of volatile components from Atractylodes chinensis using headspace solid-phase microextraction (HS-SPME). RESULTS: A total of 167 volatile metabolites were extracted, and 137 substances were matched with NIST and Wiley databases. Among them, 76 compounds exhibited significant differences between the two sources; these mainly included terpenes, aromatics, and esters. KEGG enrichment analysis indicated that the differential metabolites were primarily involved in the biosynthesis of secondary metabolites, terpene biosynthesis, and limonene and pinene degradation; all these pathways have geranyl diphosphate (GDP) as the common link. CONCLUSION: The total content of volatile substances extracted from wild Atractylodes chinensis was 2.5 times higher than that from the cultured variety; however, each source had different dominant metabolites. This study underscores the necessity for protecting wild Atractylodes chinensis resources, while enhancing the quality of cultivated Atractylodes chinensis.

Modified Metabolism and Response to UV Radiation: Gene Expression Variations Along an Elevational Gradient in the Asiatic Toad (Bufo gargarizans).

High-elevation adaptation provides an excellent system for examining adaptive evolution, and adaptive variations may manifest at gene expression or any other phenotypic levels. We examined gene expression profiles of Asiatic toads (Bufo gargarizans) along an elevational gradient from both wild and common-garden acclimated populations. Asiatic toads originated from high altitudes have distinctive gene expression patterns. We identified 18 fixed differentially expressed genes (DEGs), which are different in both wild and acclimated samples, and 1217 plastic DEGs, which are different among wild samples. The expression levels of most genes were linearly correlated with altitude gradient and down-regulated in high-altitude populations. Expression variations of several genes associated with metabolic process are fixed, and we also identified a co-expression module that is significantly different between acclimated populations and has functions related to DNA repair. The differential expression of the vast majority genes, however, are due to phenotypic plasticity, revealing the highly plastic nature of gene expression variations. Expression modification of some specific genes related to metabolism and response to UV radiation play crucial role in adaptation to high altitude for Asiatic toads. Common-garden experiments are essential for evaluating adaptive evolution of natural populations.

Low-profile visualized intraluminal support stent for the endovascular treatment of traumatic intracranial internal carotid artery pseudoaneurysms.

Optimal treatment strategies for traumatic intracranial internal carotid artery (ICA) pseudoaneurysms are controversial. The low-profile visualized intraluminal support (LVIS) device is a braided stent with a metal coverage rate between traditional laser cut stents and flow diversion devices. We report here our therapy strategy using the LVIS stent-assisted coiling for treatment of traumatic intracranial ICA pseudoaneurysms. Patients with traumatic intracranial ICA pseudoaneurysms treated by the LVIS stent-assisted coiling in our center between January 2015 and June 2021 were reviewed. The complications, radiographic, and clinical outcomes of these patients were analyzed. A total of 12 patients with 12 pseudoaneurysms were included. The mean maximum aneurysm diameter was 6.2 ± 3.1 mm. Nine patients had a subarachnoid hemorrhage; five patients with Hunt-Hess grade III and four patients with grade IV. All procedures were successfully performed without intraoperative complications. Immediate postoperative angiogram showed that six (50%) aneurysms were Raymond grade 1, four (33.3%) were grade 2, and two (16.7%) were grade 3. Postoperative multiple cerebral infarction occurred in two patients because of vasospasm. Of the ten patients with angiographic follow-up (mean, 29.9 months), two received additional coiling because of recanalization of the pseudoaneurysm, and all aneurysms were completely obliterated at the last examination of the patients. During the clinical follow-up period (mean, 26.8 months), the overall mortality and morbidity were 25% (3/12) and 8.3% (1/12), respectively. LVIS stent-assisted coiling was a feasible approach for the treatment of traumatic ICA pseudoaneurysms.

Usefulness of Silent Magnetic Resonance Angiography in the Follow-Up of Endovascular-Treated Intracranial Aneurysm: A Prospective Study.

OBJECTIVES: To prospectively evaluate the clinical usefulness of Silent magnetic resonance angiography (Silent MRA) in the follow-up of endovascular-treated intracranial aneurysms by comparing it with time-of-flight magnetic resonance angiography (TOF MRA) and digital subtraction angiography (DSA). METHODS: Patients with endovascular-treated saccular aneurysms and followed with Silent MRA, TOF MRA, and DSA in our center were included. The visualization of the treated sites in the two MRA sequences was assessed using a 5-point scale. The aneurysm occlusion status according to each of the three imaging modalities was assessed using a 3-point scale. RESULTS: Forty-one patients with 46 saccular aneurysms were recruited. The image quality score of Silent MRA was significantly higher than that of TOF MRA (4.32 ± 0.87 vs. 3.08 ± 1.48, P < 0.001). In the aneurysms treated by simple coiling, the maximal aneurysm diameter showed a strong negative correlation with image quality score in TOF MRA (Spearman's r = -0.519, P = 0.033), while it showed no significant correlation in Silent MRA (r = -0.037, P = 0.887). For the aneurysm occlusion status, inter-modality agreement was excellent (κ = 0.845) between DSA and Silent MRA, but poor (κ = 0.185) between DSA and TOF MRA. CONCLUSIONS: Silent MRA was superior to TOF MRA in the follow-up of endovascular-treated intracranial aneurysms and showed excellent consistency with DSA in the evaluation of aneurysm occlusion. Therefore, Silent MRA is useful for the follow-up of endovascular-treated aneurysms.

ASH2L regulates ubiquitylation signaling to MLL: trans-regulation of H3 K4 methylation in higher eukaryotes.

Crosstalk between H2B ubiquitylation (H2Bub) and H3 K4 methylation plays important roles in coordinating functions of diverse cofactors during transcription activation. The underlying mechanism for this trans-tail signaling pathway is poorly defined in higher eukaryotes. Here, we show the following: (1) ASH2L in the MLL complex is essential for H2Bub-dependent H3 K4 methylation. Deleting or mutating K99 of the N-terminal winged helix (WH) motif in ASH2L abrogates H2Bub-dependent regulation. (2) Crosstalk can occur in trans and does not require ubiquitin to be on nucleosomes or histones to exert regulatory effects. (3) trans-regulation by ubiquitin promotes MLL activity for all three methylation states. (4) MLL3, an MLL homolog, does not respond to H2Bub, highlighting regulatory specificity for MLL family histone methyltransferases. Altogether, our results potentially expand the classic histone crosstalk to nonhistone proteins, which broadens the scope of chromatin regulation by ubiquitylation signaling.

Structural basis for activation of SAGA histone acetyltransferase Gcn5 by partner subunit Ada2.

The Gcn5 histone acetyltransferase (HAT) subunit of the SAGA transcriptional coactivator complex catalyzes acetylation of histone H3 and H2B N-terminal tails, posttranslational modifications associated with gene activation. Binding of the SAGA subunit partner Ada2 to Gcn5 activates Gcn5's intrinsically weak HAT activity on histone proteins, but the mechanism for this activation by the Ada2 SANT domain has remained elusive. We have employed Fab antibody fragments as crystallization chaperones to determine crystal structures of a yeast Ada2/Gcn5 complex. Our structural and biochemical results indicate that the Ada2 SANT domain does not activate Gcn5's activity by directly affecting histone peptide binding as previously proposed. Instead, the Ada2 SANT domain enhances Gcn5 binding of the enzymatic cosubstrate acetyl-CoA. This finding suggests a mechanism for regulating chromatin modification enzyme activity: controlling binding of the modification cosubstrate instead of the histone substrate.

Exchange of associated factors directs a switch in HBO1 acetyltransferase histone tail specificity.

Histone acetyltransferases (HATs) assemble into multisubunit complexes in order to target distinct lysine residues on nucleosomal histones. Here, we characterize native HAT complexes assembled by the BRPF family of scaffold proteins. Their plant homeodomain (PHD)-Zn knuckle-PHD domain is essential for binding chromatin and is restricted to unmethylated H3K4, a specificity that is reversed by the associated ING subunit. Native BRPF1 complexes can contain either MOZ/MORF or HBO1 as catalytic acetyltransferase subunit. Interestingly, while the previously reported HBO1 complexes containing JADE scaffold proteins target histone H4, the HBO1-BRPF1 complex acetylates only H3 in chromatin. We mapped a small region to the N terminus of scaffold proteins responsible for histone tail selection on chromatin. Thus, alternate choice of subunits associated with HBO1 can switch its specificity between H4 and H3 tails. These results uncover a crucial new role for associated proteins within HAT complexes, previously thought to be intrinsic to the catalytic subunit.

TMD1 domain and CRAC motif determine the association and disassociation of MxIRT1 with detergent-resistant membranes.

Iron is essential for most living organisms. The iron-regulated transporter1 (IRT1) plays a major role in iron uptake in roots, and its trafficking from endoplasmic reticulum (ER) to plasma membrane (PM) is tightly coordinated with changes in iron environment. However, studies on the IRT1 response are limited. Here, we report that Malus xiaojinesis IRT1 (MxIRT1) associates with detergent-resistant membranes (DRMs, a biochemical counterpart of PM microdomains), whereas the PM microdomains are known platforms for signal transduction in the PM. Depending on the shift of MxIRT1 from microdomains to homogeneous regions in PM, MxIRT1-mediated iron absorption is activated by the cholesterol recognition/interaction amino acid consensus (CRAC) motif of MxIRT1. MxIRT1 initially associates with DRMs in ER via its transmembrane domain 1 (TMD1), and thus begins DRMs-dependent intracellular trafficking. Subsequently, MxIRT1 is sequestered in COPII vesicles via the ER export signal sequence in MxIRT1. These studies suggest that iron homeostasis is influenced by the CRAC motif and TMD1 domain due to their determination of MxIRT1-DRMs association.

Metabolomic changes of blood plasma associated with two phases of rat OIR.

Although acute hyperoxia/hypoxia alternation can shift sharply physiological processes of vessel development, e.g. oxygen induced retinopathy (OIR), very little is known of metabolic products resulted from the neovascularization disorder. In this study, the influence of abnormal oxygen exposures on the plasma metabolomic profiles of rats with OIR was investigated by the gas chromatography mass spectrometry (GC-MS). Rat pups were divided into four groups, each with 12 individuals: (i) reared in room air and sampled at P12 (CT1); (ii) exposed to high oxygen for 5 days and sampled at P12 (HO1, simulating the vaso-obeliteration process (phase I)); (iii) reared in room air and sampled at P17 (CT2); (iv) exposed to high oxygen for 5 days then followed by room air for 5 days and sampled at P17 (HO2, simulating the neovasculization one (phase II)). Plasma samples were analyzed with GC-MS, resulted in 122 metabolite species. Distinct differences in the plasma metabolome were found between groups of CT1 vs. HO1, and HO1 vs. HO2, by using univariate and multivariate analyses. Alternating hyperoxia/hypoxia conditions induced significant changes of richness of proline, ornithine and glutamine, that were important components of 'arginine and proline metabolism' pathway. These metabolites contributed largely to plasma sample classification, determined with receiver operating characteristic curve analysis and were involved profoundly in the proline-dependent production of reactive oxygen species (ROS) related to the cellular redox reactions. Our results from the rat OIR model suggest proline and 'arginine and proline metabolism' pathway as the potential biomarkers for human retinopathy of prematurity (ROP) diagnosis.

Limits to sustained energy intake. XXX. Constraint or restraint? Manipulations of food supply show peak food intake in lactation is constrained.

Lactating mice increase food intake 4- to 5-fold, reaching an asymptote in late lactation. A key question is whether this asymptote reflects a physiological constraint, or a maternal investment strategy (a 'restraint'). We exposed lactating mice to periods of food restriction, hypothesizing that if the limit reflected restraint, they would compensate by breaching the asymptote when refeeding. In contrast, if it was a constraint, they would by definition be unable to increase their intake on refeeding days. Using isotope methods, we found that during food restriction, the females shut down milk production, impacting offspring growth. During refeeding, food intake and milk production rose again, but not significantly above unrestricted controls. These data provide strong evidence that asymptotic intake in lactation reflects a physiological/physical constraint, rather than restraint. Because hypothalamic neuropeptide Y (Npy) was upregulated under both states of restriction, this suggests the constraint is not imposed by limits in the capacity to upregulate hunger signalling (the saturated neural capacity hypothesis). Understanding the genetic basis of the constraint will be a key future goal and will provide us additional information on the nature of the constraining factors on reproductive output, and their potential links to life history strategies.