Ano1 regulates embryo transport by modulating intracellular calcium levels in oviduct smooth muscle.

Oviductal smooth muscle exhibits spontaneous rhythmic contraction (SRC) and controls the passage of the ova at the exact time, but its mechanistic regulation remains to be determined. In this study, female mice with Ano1SMKO (smooth muscle-specific deletion of Ano1) had reduced fertility. Deficiency of Ano1 in mice resulted in impaired oviductal SRC function and reduced calcium signaling in individual smooth muscle cells in the oviduct. The Ano1 antagonist T16Ainh-A01 dose-dependently inhibited SRCs and [Ca2+]i in the oviducts of humans and mice. A similar inhibitory effect of SRCs and [Ca2+]i was observed after treatment with nifedipine. In our study, ANO1 acted primarily as an activator or amplifier in [Ca2+]i and contraction of tubal smooth muscle cells. We found that tubal SRC was markedly attenuated in patients with ectopic pregnancy. Then, our study was designed to determine whether chloride channel Ano1-mediated smooth muscle motility is associated with tubal SRC. Our findings reveal a new mechanism for the regulation of tubal motility that may be associated with abnormal pregnancies such as ectopic pregnancies.

Lifelong-MonoDepth: Lifelong Learning for Multidomain Monocular Metric Depth Estimation.

With the rapid advancements in autonomous driving and robot navigation, there is a growing demand for lifelong learning (LL) models capable of estimating metric (absolute) depth. LL approaches potentially offer significant cost savings in terms of model training, data storage, and collection. However, the quality of RGB images and depth maps is sensor-dependent, and depth maps in the real world exhibit domain-specific characteristics, leading to variations in depth ranges. These challenges limit existing methods to LL scenarios with small domain gaps and relative depth map estimation. To facilitate lifelong metric depth learning, we identify three crucial technical challenges that require attention: 1) developing a model capable of addressing the depth scale variation through scale-aware depth learning; 2) devising an effective learning strategy to handle significant domain gaps; and 3) creating an automated solution for domain-aware depth inference in practical applications. Based on the aforementioned considerations, in this article, we present 1) a lightweight multihead framework that effectively tackles the depth scale imbalance; 2) an uncertainty-aware LL solution that adeptly handles significant domain gaps; and 3) an online domain-specific predictor selection method for real-time inference. Through extensive numerical studies, we show that the proposed method can achieve good efficiency, stability, and plasticity, leading the benchmarks by 8%-15%. The code is available at https://github.com/FreeformRobotics/Lifelong-MonoDepth.

Toward Better Accuracy-Efficiency Trade-Offs: Divide and Co-Training.

The width of a neural network matters since increasing the width will necessarily increase the model capacity. However, the performance of a network does not improve linearly with the width and soon gets saturated. In this case, we argue that increasing the number of networks (ensemble) can achieve better accuracy-efficiency trade-offs than purely increasing the width. To prove it, one large network is divided into several small ones regarding its parameters and regularization components. Each of these small networks has a fraction of the original one's parameters. We then train these small networks together and make them see various views of the same data to increase their diversity. During this co-training process, networks can also learn from each other. As a result, small networks can achieve better ensemble performance than the large one with few or no extra parameters or FLOPs, i. e., achieving better accuracy-efficiency trade-offs. Small networks can also achieve faster inference speed than the large one by concurrent running. All of the above shows that the number of networks is a new dimension of model scaling. We validate our argument with 8 different neural architectures on common benchmarks through extensive experiments.

Hypoxia promotes thyroid cancer progression through HIF1α/FGF11 feedback loop.

Hypoxia is an important cause of cervical lymph nodes metastasis and recurrence of thyroid cancer, but its specific mechanism remains unclear. In the present study, we constructed a hypoxia model of thyroid cancer cells and explored the potential targets of hypoxia response through sequencing. The function and mechanism of the target protein were investigated in an in vitro cell model. We found that fibroblast growth factor 11 (FGF11), a member of the FGFs family, was upregulated in hypoxic thyroid cancer cells and thyroid cancer tissues. The knockdown of FGF11 blocked the promotion of hypoxia on the proliferation, migration and invasion of tumor cells. Importantly, FGF11 enhanced the stability of HIF1α through inhibiting its degradation in TPC-1 cells. under hypoxic condition, FGF11 formed a positive feedback loop with HIF1α to promote the growth and metastasis of thyroid cancer.

Evaluation of Silibinin-Loaded Microbubbles Combined with Ultrasound in Ovarian Cancer Cells: Cytotoxicity and Mechanisms.

BACKGROUND: The anticancer activity of silibinin (SB) has been demonstrated in various cancer cell types. However, its low solubility and poor bioavailability limit its clinical potential in biomedical applications. Microbubbles in combination with ultrasound are promising vehicles for local drug delivery. OBJECTIVE: The present study determined the antitumour effects and molecular mechanism of silibinin-loaded microbubbles (SBMBs) in combination with ultrasound on ovarian cancer in vitro. METHODS: SBMBs were prepared using mechanical vibration. The viability of A2780 cells was determined using the MTT assay. Flow cytometry was performed to detect cell apoptosis and the cell cycle. The expression of Receptor Tyrosine Kinase (RTK)-associated downstream proteins was detected using multiplex assays and Western blots. RESULTS: The present study designed and synthesized SBMBs. SBMBs in combination with ultrasound decreased A2780 cell viability in a dose- and time-dependent manner. The half maximal inhibitory concentration (IC50) showed that the cytotoxicity of the SBMBs was approximately 1.5 times greater than that of the SB in A2780 cells. SBMBs in combination with ultrasound resulted in significantly higher apoptosis efficiency compared to the SB group, and the SBMB population of cells was arrested in the G1/G0 phase. Further experiments demonstrated that SBMBs decreased the expression of signal transducer and activator of transcription 3 (STAT3), Ak strain transforming (AKT), and extracellular signal-regulated kinase (Erk) and had a greater effect than SB in A2780 cells. Inhibitors of AKT, Erk and STAT3 promoted the cytotoxicity of SBMBs. CONCLUSION: SBMBs in combination with ultrasound may enhance the cytotoxicity efficiency of SB via the promotion of apoptosis and cell cycle arrest in ovarian cancer cells and the inactivation of the STAT3, AKT and Erk signalling pathways.

Influence Factors for Lymph Node Metastasis in Papillary Thyroid Carcinoma: Hashimoto's Thyroiditis Has a Weak Effect on Central or Lateral Lymph Node Metastasis.

PURPOSE: To analyze the effect of Hashimoto's thyroiditis (HT) concurrent with papillary thyroid cancer (PTC) on cervical lymph node metastasis (LNM). METHODS: Two thousand nine hundred twenty-six patients who underwent thyroidectomy and lymph node dissection between January 2015 and December 2018 were enrolled in this study. Patient demographics and clinicopathologic features were analyzed. RESULTS: Of the total enrolled patients, 598 (20.4%) had concurrent HT. There were 1482 PTC cases with N0, 1033 cases with N1a, and 411 cases with N1b. Patients with HT had lower frequency of extrathyroidal extension (ETE), lymphatic vascular (LV) invasion, high pathological T stage (III+IV) and central LNM rate. Stratifying central LNM by non-ETE or without intrathyroidal spreading, it was further found that central LNM rate in patients with HT was lower than that of patients without HT. However, there was no significant difference in the central LNM rate in patients with PTC stratified by ETE or intrathyroidal spreading. HT with PTC played a weak protective role in N1a, reducing the risk of N1a by 16.4%. Conversely, HT is a risk factor for N1b, increasing the risk by 1.336 times compared to patients without HT. TgAb is an independent risk factor for N1b, which appears related to the promotion of N1b by HT. CONCLUSION: In PTC, HT has a protective effect on central LNM and a risk effect on lateral LNM, although the difference was not significant. This weak protective effect on N1a is more obvious in PTC with less aggressive clinicopathologic characteristics. The risk effect of HT on N1b may be associated with TgAb.

Risk Factors and Prediction Model for Lateral Lymph Node Metastasis of Papillary Thyroid Carcinoma in Children and Adolescents.

PURPOSE: Papillary thyroid carcinoma (PTC) in children and adolescents is prone to lateral lymph node metastasis (LNM), which is a high-risk factor for recurrence. However, few studies focused on identifying risk factors and establishing prediction models for lateral LNM of PTC in children and adolescents. PATIENTS AND METHODS: We retrospectively reviewed consecutive cases of children and adolescents with PTC undergoing thyroidectomy and cervical lymph node dissection between January 2009 and December 2019. The demographics and clinicopathologic features were collected and analyzed. RESULTS: A total of 102 children and adolescents with PTC were enrolled in our study; 51 of whom had lateral LNM (50%). After adjusting for other risk factors, the independent risk factors for lateral LNM were multifocality (odds ratio [OR]: 6.04; 95% confidence interval [CI]: 1.653-22.092; p=0.007), tumor size (OR: 1.752; 95% CI: 1.043-2.945; p=0.034), and the number of central LNM (OR: 1.23; 95% CI: 1.028-1.472; p=0.023). The formula of the combined predictor is: Multifocality + 0.31 × Tumor size + 0.115 × Number of central LNM. The area under the receiver operating characteristic curve of multifocality, tumor size, number of central LNM, and the combined predictor was 0.706, 0.762, 0.748, and 0.855, respectively. When the value of the combined predictor was ≥2.2744, lateral LNM could be predicted. The sensitivity and specificity of the predicted value were 82.4% and 74.5%, respectively. CONCLUSION: The independent risk factors for lateral LNM in children and adolescents with PTC were multifocality, tumor size, and the number of central LNM. The prediction model can better predict the presence of lateral LNM.

Pretracheal-laryngeal lymph nodes in frozen section predicting contralateral paratracheal lymph nodes metastasis.

BACKGROUND: There has been an ongoing debate concerning the predictors of contralateral paratracheal lymph nodes metastasis (LNM) in unilateral papillary thyroid cancer (PTC). This study aimed to explore the value of pretracheal-laryngeal lymph nodes (LNs) in frozen section in predicting contralateral paratracheal LNM. METHODS: A total of 242 patients with unilateral PTC were enrolled in this prospective study. Patients who underwent total thyroidectomy and bilateral central lymph nodes dissection (LND) were divided into two groups according to positive or negative contralateral paratracheal LNs. Patients' demographics and clinicopathological features were compared between the two groups. Validity indexes and consistency of pretracheal-laryngeal LNs in frozen sections were calculated. RESULTS: LNM rates in central, ipsilateral paratracheal, pretracheal-laryngeal, and contralateral paratracheal regions were 55.37%, 47.03%, 23.55% and 14.05%, respectively. Only pretracheal-laryngeal LNM, regardless of whether detected in frozen or paraffin sections, were independent risk factors for contralateral paratracheal LNM (OR = 2.707; 95% CI 1.062-6.902; P = 0.037 in frozen section; OR = 3.072; 95% CI 1.248-7.560; P = 0.015 in paraffin section). The sensitivity, specificity, false-negative rate, false-positive rate, accuracy rate, and Kappa value of pretracheal-laryngeal LNM in frozen sections for predicting pretracheal-laryngeal LNM were 87.72%, 100%, 12.28%, 0%, 97.11% and 0.916 respectively, while those for predicting contralateral paratracheal LNM were 85,29%, 89.90%, 14.71%, 10.10%, 89.22%, and 0.618 respectively. CONCLUSION: Pretracheal-laryngeal LNs in frozen section accurately predicted contralateral paratracheal LNM, which could allow the identification of patients who can benefit from an extended central LND.

Isthmic Papillary Thyroid Carcinoma Presents a Unique Pattern of Central Lymph Node Metastasis.

PURPOSE: Treatment protocols for occult central lymph node metastasis (LNM) associated with papillary thyroid cancer (PTC) located in the isthmus are debatable. We aimed to analyze the pattern of occult central LNM in isthmic PTC, including risk factors for bilateral paratracheal LNM. PATIENTS AND METHODS: Consecutive patients with PTC were recruited to this study. All patients underwent total thyroidectomy and prophylactic bilateral central neck dissection. The clinicopathologic features and distribution of central LNM were compared between the two groups, and risk factors for bilateral paratracheal LNM were analyzed. RESULTS: A total of 174 patients with PTC were enrolled in this study, of whom 87 patients had isthmic PTC (study group) and 87 patients had lobe-originating PTC (control group). The two groups had comparable demographics and tumor features. There were higher frequencies of pretracheal LNM (P =0.001) and bilateral paratracheal LNM (P = 0.002) in the isthmic PTC group. Bilateral paratracheal LNM was significantly associated with age <55 years (P = 0.037), capsular invasion (P = 0.034), tumor location (isthmus) (P < 0.001), BRAF gene mutation (P = 0.013), and pretracheal LNM (P < 0.001). Isthmus location (odds ratio [OR]: 4.116, 95% confidence interval [CI]: 1.264-13.433, P = 0.019) and pretracheal LNM (OR: 3.422, 95% CI: 1.214-9.642, P = 0.020) were independent risk factors for bilateral paratracheal LNM. CONCLUSION: Because of its unique anatomic location, isthmic PTC differs from PTC in the lobe with respect to pretracheal and bilateral paratracheal LNM, even in patients of comparable age, sex, tumor size, extrathyroidal extension, BRAF mutation, and pathologic TNM staging. The isthmus location was found to be an independent risk factor for bilateral paratracheal LNM. This information may contribute to the development of an appropriate surgical protocol for isthmic PTC.

Increased risk of maternal and neonatal complications in hormone replacement therapy cycles in frozen embryo transfer.

BACKGROUND: The endometrial preparation during frozen embryo transfer (FET) can be performed by natural cycle (NC), hormone replacement therapy (HRT) cycle and cycle with ovulation induction (OI). Whether different FET preparation protocols can affect maternal and neonatal outcomes is still inconclusive. METHODS: This was a retrospective cohort study that included 6886 women who delivered singleton live birth babies after 28 weeks of pregnancy underwent FET from January, 2015 to July, 2018. Women were divided into three groups according to the protocols used for endometrial preparation during FET: NC group (N = 4727), HRT group (N = 1642) and OI group (N = 517). RESULTS: After adjusting for the effect of age, body mass index (BMI), irregular menstruation, antral follicle count (AFC), endometrial thickness, the levels of testosterone, anti-Müllerian hormone (AMH), preconceptional fasting glucose (PFG), systolic and diastolic pressure et al., the HRT group had higher risk of hypertensive disorders of pregnancy (HDP) compared with the NC group (adjusted odds ratio (aOR) 2.00, 95% confidence interval (CI) 1.54-2.60). Singletons born after HRT FET were at increased risk of low birth weight (LBW) compared to NC group (aOR 1.49, 95%CI 1.09-2.06). The risks of preterm birth (PTB) in the HRT and OI group were elevated compared with the NC group (aOR 1.78, 95%CI 1.39-2.28 and aOR 1.51, 95%CI 1.02-2.23, respectively). CONCLUSIONS: The HRT protocol for endometrial preparation during frozen embryo transfer of blastocysts was associated with increased risk of maternal and neonatal complications, compared to the NC and OI protocol.

The effect of vitamin D supplementation on the risk of breast cancer: a trial sequential meta-analysis.

BACKGROUND AND OBJECTIVE: Observational studies suggest an inverse association between circulating vitamin D levels and risk of breast cancer. However, the potential benefits of vitamin D supplementation to reduce the risk of breast cancer remain controversial, based on the results of current randomized controlled trials (RCTs). The aim of this study was to evaluate the value of vitamin D supplementation on breast cancer prevention. METHODS: PubMed, Embase, and Cochrane library were searched from inception to February 2020. We performed a trial sequential meta-analysis of RCTs reporting the effect of vitamin D supplementation, with or without calcium, on the risk of breast cancer. The effect was estimated using a relative risk reduction threshold of 30%. RESULTS: Eight trials comprising 72,275 participants were included in this study, with a median follow-up period ranging from 1 to 11.9 years. The median dosage of vitamin D supplementation was 967 IU per day (range 400-3704 IU per day) across the trials. This study yielded a relative risk of 1.04 (95% CI 0.85-1.29, P = 0.68) for the effect of vitamin D supplementation (6 trials, 33,472 participants), and 0.99 (95% CI 0.91-1.07, P = 0.73) for co-administration of vitamin D and calcium (4 trials, 41,957 participants). The effect estimate for vitamin D with or without calcium on breast cancer risk lay within the futility boundary, indicating that vitamin D supplementation does not alter the relative risk by 30% or more. CONCLUSION: Our analyses suggest that vitamin D supplementation, with or without calcium, does not reduce breast cancer risk by 30% or more. Future trials with similar designs are unlikely to alter this finding.

Hotspot of dissimilatory nitrate reduction to ammonium (DNRA) process in freshwater sediments of riparian zones.

Dissimilatory nitrate reduction to ammonium (DNRA), an important intermediate process in the N-cycle, links N-compound oxidation and reduction processes. Hence, the oxic-anoxic interface would be the hotspot of the DNRA process. In freshwater ecosystems, the riparian zone is the most typical carrier of the oxic-anoxic interface. Here we report spatio-temporal evidence of a higher abundance and rate of DNRA in the riparian zone than in the open water sediments based on molecular and 15N isotopic-tracing technologies, hence signifying a hotspot for the DNRA process. These abudance and rates were significantly higher than those in open water sediments. 15N isotopic paring technology revealed that the DNRA hotspot promoted higher rates of N-compound oxidation (NO2-), reduction (NO3- and DNRA), and N2 production (anammox and denitrification) in the riparian zone than those in open water sediment. However, high-through sequencing analysis showed that the DNRA bacteria in the riparian zone and openwater sediments were insignificantly different. Network and correlation analysis showed that the DNRA abundance and rates were significantly positively correlated with TOM, TC/NH4+, and TC/NO2-, but not with the dominant genera (Anaeromyxobacter, Lacunisphaera, and Sorangium), which played different roles on the connection in the respective community networks. The DNRA process in the riparian zone could be driven mainly by the related environmental biogeochemical characteristics induced by anthropogenic changes, followed by microbial processes. This result provides valuable information for the management of riparian zones because anthropogenic changes in the riparian water table are expected to increase, inducing consequent changes in the reduction from NO3- to NH4+.

The archaeal RNA chaperone TRAM0076 shapes the transcriptome and optimizes the growth of Methanococcus maripaludis.

TRAM is a conserved domain among RNA modification proteins that are widely distributed in various organisms. In Archaea, TRAM occurs frequently as a standalone protein with in vitro RNA chaperone activity; however, its biological significance and functional mechanism remain unknown. This work demonstrated that TRAM0076 is an abundant standalone TRAM protein in the genetically tractable methanoarcheaon Methanococcus maripaludis. Deletion of MMP0076, the gene encoding TRAM0076, markedly reduced the growth and altered transcription of 55% of the genome. Substitution mutations of Phe39, Phe42, Phe63, Phe65 and Arg35 in the recombinant TRAM0076 decreased the in vitro duplex RNA unfolding activity. These mutations also prevented complementation of the growth defect of the MMP0076 deletion mutant, indicating that the duplex RNA unfolding activity was essential for its physiological function. A genome-wide mapping of transcription start sites identified many 5' untranslated regions (5'UTRs) of 20-60 nt which could be potential targets of a RNA chaperone. TRAM0076 unfolded three representative 5'UTR structures in vitro and facilitated the in vivo expression of a mCherry reporter system fused to the 5'UTRs, thus behaving like a transcription anti-terminator. Flag-tagged-TRAM0076 co-immunoprecipitated a large number of cellular RNAs, suggesting that TRAM0076 plays multiple roles in addition to unfolding incorrect RNA structures. This work demonstrates that the conserved archaeal RNA chaperone TRAM globally affects gene expression and may represent a transcriptional element in ancient life of the RNA world.

Resuscitation of anammox bacteria after >10,000 years of dormancy.

Water is essential for life on Earth, and an important medium for microbial energy and metabolism. Dormancy is a state of low metabolic activity upon unfavorable conditions. Many microorganisms can switch to a metabolically inactive state after water shortage, and recover once the environmental conditions become favorable again. Here, we resuscitated dormant anammox bacteria from dry terrestrial ecosystems after a resting period of >10 ka by addition of water without any other substrates. Isotopic-tracer analysis showed that water induced nitrate reduction yielding sufficient nitrite as substrate and energy for activating anammox bacteria. Subsequently, dissimilatory nitrate reduction to ammonium (DNRA) provided the substrate ammonium for anammox bacteria. The ammonium and nitrite formed were used to produce dinitrogen gas. High throughput sequencing and network analysis identified Brocadia as the dominant anammox species and a Jettenia species seemed to connect the other community members. Under global climate change, increasing precipitation and soil moisture may revive dormant anammox bacteria in arid soils and thereby impact global nitrogen and carbon cycles.

Conserved TRAM Domain Functions as an Archaeal Cold Shock Protein via RNA Chaperone Activity.

Cold shock proteins (Csps) enable organisms to acclimate to and survive in cold environments and the bacterial CspA family exerts the cold protection via its RNA chaperone activity. However, most Archaea do not contain orthologs to the bacterial csp. TRAM, a conserved domain among RNA modification proteins ubiquitously distributed in organisms, occurs as an individual protein in most archaeal phyla and has a structural similarity to Csp proteins, yet its biological functions remain unknown. Through physiological and biochemical studies on four TRAM proteins from a cold adaptive archaeon Methanolobus psychrophilus R15, this work demonstrated that TRAM is an archaeal Csp and exhibits RNA chaperone activity. Three TRAM encoding genes (Mpsy_0643, Mpsy_3043, and Mpsy_3066) exhibited remarkable cold-shock induced transcription and were preferentially translated at lower temperature (18°C), while the fourth (Mpsy_2002) was constitutively expressed. They were all able to complement the cspABGE mutant of Escherichia coli BX04 that does not grow in cold temperatures and showed transcriptional antitermination. TRAM3066 (gene product of Mpsy_3066) and TRAM2002 (gene product of Mpsy_2002) displayed sequence-non-specific RNA but not DNA binding activity, and TRAM3066 assisted RNases in degradation of structured RNA, thus validating the RNA chaperone activity of TRAMs. Given the chaperone activity, TRAM is predicted to function beyond a Csp.

Minichromosome maintenance complex component 8 mutations cause primary ovarian insufficiency.

OBJECTIVE: To investigate whether mutations in the minichromosome maintenance complex component 8 (MCM8) gene were present in 192 patients with sporadic primary ovarian insufficiency (POI). DESIGN: Retrospective case-control cohort study. SETTING: University-based reproductive medicine center. PATIENT(S): A total of 192 patients with sporadic POI and 312 control women with regular menstruation (192 age-matched women and 120 women >45 years old). INTERVENTION(S): Sanger sequencing was performed in patients with sporadic POI, and potentially pathogenic variants were confirmed in matched controls. DNA damage was induced by mitomycinC (MMC) treatment, and DNA repair capacity was evaluated by histone H2AX phosphorylation level. MAIN OUTCOME MEASURE(S): Sanger sequencing for MCM8 was performed in 192 patients with sporadic POI, and functional experiments were performed to explore the deleterious effects of mutations identified. RESULT(S): Two novel missense variants in MCM8, c. A950T (p. H317L), and c. A1802G (p. H601R), were identified in two patients with POI but absent in 312 controls (the upper 90% confidence limit for the proportion 2/192 is 2.24%). The HeLa cells overexpressing mutant p. H317L and p. H601R showed higher sensitivity to MMC compared with wild type. Furthermore, mutant p. H317L showed decreased repair capacity after MMC treatment with much more histone H2AX phosphorylation remaining after 2 hours of recovery. CONCLUSION(S): Our result suggests novel mutations p. H317L and p. H601R in the MCM8 gene are potentially causative for POI by dysfunctional DNA repair.

Sonographic features of medullary thyroid carcinomas according to tumor size: comparison with papillary thyroid carcinomas.

OBJECTIVES: The aim of this study was to evaluate the differences in sonographic features of medullary thyroid carcinomas according to nodule size and compared with findings for papillary thyroid carcinomas. METHODS: This study included 38 medullary thyroid carcinoma nodules and 91 papillary thyroid carcinoma nodules, which were confirmed by pathologic examination between May 2008 and September 2013. Nodules were divided into those that were greater than 10 mm (large nodules) and 10 mm or less (small nodules). The differences in sonographic features (composition, echogenicity, margin, calcifications, and shape) between groups were analyzed with a χ(2) test. RESULTS: Large medullary thyroid carcinomas more frequently showed an ovoid-to-round shape and a smooth margin; small medullary thyroid carcinomas more frequently showed a taller-than-wide shape and a spiculated margin; the differences were statistically significant between the groups (P < .05). Compared with papillary thyroid carcinomas, large medullary thyroid carcinomas tended to have an ovoid-to-round shape, a smooth margin, and macrocalcifications and were more frequently diagnosed as indeterminate nodules (P < .05); however, there were no significant differences in the internal composition, calcifications, echogenicity, margin, and shape between small medullary thyroid carcinomas and small papillary thyroid carcinomas (P > .05). CONCLUSIONS: Our data indicate that the sonographic features of medullary thyroid carcinomas are associated with tumor size; furthermore, the sonographic features of medullary thyroid carcinomas are similar to those of small papillary thyroid carcinomas but greatly different from those of large papillary thyroid carcinomas. Large medullary thyroid carcinomas are more commonly diagnosed as indeterminate nodules by sonography than large papillary thyroid carcinomas, and fine-needle aspiration biopsy or serum calcitonin measurement may be helpful.

Transcriptomic and physiological insights into the robustness of long filamentous cells of Methanosaeta harundinacea, prevalent in upflow anaerobic sludge blanket granules.

Methanosaeta spp. are widely distributed in natural environments, and their filamentous cells contribute significantly to sludge granulation and the good performance of anaerobic reactors. A previous study indicated that Methanosaeta harundinacea 6Ac displays a quorum sensing-regulated morphological transition from short to long filaments, and more acetate is channeled into methane production in long filaments, whereas more is channeled into biomass synthesis in short filaments. Here, we performed transcriptomic and physiological analysis to gain insights into active methanogenesis in long filaments of M. harundinacea 6Ac. Both RNA sequencing (RNA-seq) and quantitative reverse transcription-PCR indicated that transcription of the genes involved in aceticlastic methanogenesis and energy metabolism was upregulated 1.2- to 10.3-fold in long filaments, while transcription of the genes for the methyl oxidative shunt was upregulated in short filaments. [2-(13)C]acetate trace experiments demonstrated that a relatively higher portion of the acetate methyl group was oxidized to CO2 in short filaments than in long filaments. The long filaments exhibited higher catalase activity and oxygen tolerance than the short ones, which is consistent with increased transcription of the oxidant-scavenging genes. Moreover, transcription of genes for cell surface structures was upregulated in the long filaments, and transmission electron microscopy revealed a thicker cell envelope in the filaments. RNA-seq determined a >2-fold upregulation of a variety of antistress genes in short filaments, like those encoding chaperones and DNA repair systems, which implies that the short filaments can be stressed. This study reveals the genetic basis for the prevalence of the long filamentous morphology of M. harundinacea cells in upflow anaerobic sludge blanket granules.

Methanospirillum psychrodurum sp. nov., isolated from wetland soil.

A psychrotolerant methanogenic strain, X-18(T), was isolated from the soil of the Madoi wetland at Qinghai, Tibetan plateau, China. Cells were wavy rods (11-62 µm long) with blunt tapered ends and Gram-stain-negative. Strain X-18(T) grew strictly anaerobically and produced methane exclusively from H2/CO2. Growth occurred in the temperature range of 4-32 °C and optimally at 25 °C. Growth pH ranged from 6.5 to 8.0 and the optimum was 7.0. The G+C content of the genomic DNA of strain X-18(T) was 44.4 mol%. Phylogenetic analysis based on 16S rRNA gene sequences and the alpha subunit of methyl-coenzyme M reductase indicated that strain X-18(T) was affiliated to the genus Methanospirillum and was most closely related to Methanospirillum lacunae Ki8-1(T), with 96.3% 16S rRNA gene sequence similarity. However, strain X-18(T) could be distinguished from the existing species of the genus Methanospirillum by its lower growth temperature and obligate hydrogenotrophic methanogenesis. On the basis of phenotypic characteristics and phylogenetic analysis, strain X-18(T) represents a novel species of the genus Methanospirillum, for which the name Methanospirillum psychrodurum sp. nov. is proposed and strain X-18(T) is assigned as the type strain ( = CGMCC 1.5186(T) = JCM 19216(T)).

Acyl homoserine lactone-based quorum sensing in a methanogenic archaeon.

Acyl homoserine lactone (AHL)-based quorum sensing commonly refers to cell density-dependent regulatory mechanisms found in bacteria. However, beyond bacteria, this cell-to-cell communication mechanism is poorly understood. Here we show that a methanogenic archaeon, Methanosaeta harundinacea 6Ac, encodes an active quorum sensing system that is used to regulate cell assembly and carbon metabolic flux. The methanogen 6Ac showed a cell density-dependent physiology transition, which was related to the AHL present in the spent culture and the filI gene-encoded AHL synthase. Through extensive chemical analyses, a new class of carboxylated AHLs synthesized by FilI protein was identified. These carboxylated AHLs facilitated the transition from a short cell to filamentous growth, with an altered carbon metabolic flux that favoured the conversion of acetate to methane and a reduced yield in cellular biomass. The transcriptomes of the filaments and the short cell forms differed with gene expression profiles consistent with the physiology. In the filaments, genes encoding the initial enzymes in the methanogenesis pathway were upregulated, whereas those for cellular carbon assimilation were downregulated. A luxI-luxR ortholog filI-filR was present in the genome of strain 6Ac. The carboxylated AHLs were also detected in other methanogen cultures and putative filI orthologs were identified in other methanogenic genomes as well. This discovery of AHL-based quorum sensing systems in methanogenic archaea implies that quorum sensing mechanisms are universal among prokaryotes.