Non-syntrophic methanogenic hydrocarbon degradation by an archaeal species.

The methanogenic degradation of oil hydrocarbons can proceed through syntrophic partnerships of hydrocarbon-degrading bacteria and methanogenic archaea1-3. However, recent culture-independent studies have suggested that the archaeon 'Candidatus Methanoliparum' alone can combine the degradation of long-chain alkanes with methanogenesis4,5. Here we cultured Ca. Methanoliparum from a subsurface oil reservoir. Molecular analyses revealed that Ca. Methanoliparum contains and overexpresses genes encoding alkyl-coenzyme M reductases and methyl-coenzyme M reductases, the marker genes for archaeal multicarbon alkane and methane metabolism. Incubation experiments with different substrates and mass spectrometric detection of coenzyme-M-bound intermediates confirm that Ca. Methanoliparum thrives not only on a variety of long-chain alkanes, but also on n-alkylcyclohexanes and n-alkylbenzenes with long n-alkyl (C≥13) moieties. By contrast, short-chain alkanes (such as ethane to octane) or aromatics with short alkyl chains (C≤12) were not consumed. The wide distribution of Ca. Methanoliparum4-6 in oil-rich environments indicates that this alkylotrophic methanogen may have a crucial role in the transformation of hydrocarbons into methane.

NMR-Guided Isolation of Anti-inflammatory Carabranolides from the Fruits of Carpesium abrotanoides L.

Carabranolides present characteristic NMR resonances for the cyclopropane moiety, which distinctly differ from those of other compounds and were used for an NMR-guided isolation in this study. As a result, 11 undescribed carabranolides (1-11), along with five known ones (12-16), were isolated from the fruits of Carpesium abrotanoides L. Compounds 1-11 are new esters of carabrol at C-4 with different carboxylic acids. Their structures were elucidated by HRESIMS and NMR spectroscopic data analysis. The biological evaluation showed that compounds 2-4, 15, and 16 exhibited significant inhibitory activity against LPS-induced NO release with an IC50 value of 5.6-9.1 µM and dose-dependently decreased iNOS protein expression in RAW264.7 cells.

Atrachinenins D-S, novel meroterpenoids with geranyl hydroquinone moiety from Atractylodes chinensis by the LC/MS-based molecular decoy and targeted isolation.

To mine fascinating molecules from the rhizomes of Atractylodes chinensis, the known molecular formula of atrachinenin A was used as a bait to search LC-HRMS data in different subfractions. Sixteen new meroterpenoids, atrachinenins D-S (1-16) including three unprecedented carbon skeletons (1-5) and eleven new oxygen-bridged hybrids (6-16) were obtained by the targeted isolation. Their structures and absolute configurations were elucidated by the spectroscopic data and electronic circular dichroism (ECD) calculations. The isolated compounds were evaluated for their inhibitory activity of NO production and compounds 1, 4, 8, and 13 showed moderate anti-inflammatory activity. The proposed biosynthetic pathways of 1-5 were also discussed.

Selective Chemical Labeling Strategy for Oligonucleotides Determination: A First Application to Full-Range Profiling of Transfer RNA Modifications.

To date, the extremely high polarity and poor signal intensity of macromolecular nucleic acids are greatly impeding the progress of mass spectrometry technology in the quality control of nucleic acid drugs and the characterization of DNA oxidation and RNA modifications. We recently described a general N-(tert-butyldimethylsilyl)-N-methyl-trifluoroacetamide (MTBSTFA) labeling method for oligonucleotide determination and applied it to the full-range profiling of tRNA in vitro and in vivo studies for the first time. The primary advantages of this method include strong retention, no observable byproducts, predictable and easily interpreted MS2 data, and the circumvention of instrument harmful reagents that were necessary in previous methods. Selective labeling of N-(tert-butyldimethylsilyl)-N-methyl-trifluoroacetamide to the terminal phosphate groups of oligonucleotides endows it broadly applicable for DNA/RNA profiling. Moreover, the improvement of sequence coverage was achieved in yeast tRNAphe(GAA) analysis owing to this method's good detection capability of 1-12 nucleotides in length. We also extended this strategy to determine the abundance of modified bases and discover new modifications via digesting RNA into single-nucleotide products, promoting the comprehensive mapping of RNA. The easy availability of derivatization reagent and the simple, rapid one-step reaction render it easy to operate for researchers. When applied in characterizing tRNAs in HepG2 cells and rats with nonalcoholic fatty liver disease, a fragment of U[m1G][m2G], specific for tRNAAsn(QUU) in cells, was significantly upregulated, indicating a possible clue to nonalcoholic fatty liver disease pathogenesis.

Di- and Triterpenoids from the Rhizomes of Isodon amethystoides and Their Anti-inflammatory Activities.

Amethystoidesic acid (1), a triterpenoid with an unprecedented 5/6/6/6 tetracyclic skeleton, and six undescribed diterpenoids, amethystoidins A-F (2-7), were isolated from the rhizomes of Isodon amethystoides along with 31 known di- and triterpenoids (8-38). Their structures were fully elucidated via extensive spectroscopic analysis including 1D and 2D NMR, high-resolution electrospray ionization mass spectrometry (HRESIMS), and electronic circular dichroism (ECD) calculations. Compound 1 is the first example of a triterpenoid possessing a rare ring system (5/6/6/6) derived from a contracted A-ring and the 18,19-seco-E-ring of ursolic acid. Compounds 6, 16, 21, 22, 24, and 27 significantly inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells, which could be partly mediated by the downregulation of LPS-induced inducible nitric oxide synthase (iNOS) protein expression.

Chemical Constituents from the Fruits of Amomum kravanh and Their Role in Activating Alcohol Dehydrogenase.

Alcoholism is a worldwide health problem, and diseases caused by alcoholism are killing people every year. Amomum kravanh is a traditional Chinese medicine used to relieve hangovers. However, whether its bioactive components improve alcohol metabolism is not clear. In this study, ten new (amomumols A-J, 1-10) and thirty-five known (11-45) compounds were isolated from the fruits of Amomum kravanh by an activity-guided separation. Ten novel compounds were identified as four sesquiterpenoids (1-4), three monoterpene derivatives (5-7), two neolignans (8, 9), and a novel norsesquiterpenoid (10) with a new C14 nor-bisabolane skeleton. Their structures were determined by the comprehensive analysis of high-resolution electrospray ionization mass spectrometry (HRESIMS), nuclear magnetic resonance (NMR), and electronic circular dichroism (ECD) calculation. The effects of all isolated compounds on the activity of alcohol dehydrogenase were evaluated in vitro, and it was found that eight compounds (11, 12, 15, 18, 26, and 36-38) exhibited significant activation effects on the alcohol dehydrogenase at 50 µM.

Pharmacological targeting transient receptor potential canonical channel 6 modulates biological behaviors for cervical cancer HeLa and SiHA cell.

BACKGROUND: This study aimed to observe the effect of transient receptor potential canonical channel 6 (TRPC6) antagonist 1-(ß-[3-(4-method-phenyl) propoxy]-4-methoxyphenethyl)-1H-imidazole hydrate (SKF-96365) and its agonist 1-oleoyl-2-acetyl-sn-glycerol (OAG) on the proliferation of cervical cancer cell lines HeLa and SiHa, deoxyribonucleic acid (DNA) synthesis, cell migration, and TRPC6 expression. METHOD: Real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting were used to detect the expression of TRPC6 in HeLa and SiHa cells. The tetrazolium salt 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, the 5-ethynyl -2'- deoxyuridine (EdU) fluorescence detection assay, and a scratch test were used to detect the changes of proliferation, DNA synthesis and cell migration of HeLa and SiHa cells after SKF 96,365 and OAG acted on HeLa and SiHa cells for different lengths of time. RT-qPCR was used to detect expression changes of TRPC6 SKF-96365 and OAG treated HeLa and SiHa cells. RESULTS: TRPC6 was expressed both in HeLa and SiHa cells. The MTT assay showed that after 24 h of SKF-96365 treatment, compared with the control group, the proliferation of HeLa and SiHa cells was inhibited, and there was a statistically significant difference (p < 0.05). After 24 h of OAG, compared with the control group, the proliferation of HeLa and SiHa cells had increased, and there was a statistically significant difference (p < 0.05). EdU fluorescence detection showed that SKF-96365 could inhibit the DNA synthesis of HeLa and SiHa cells, and OAG could promote the DNA synthesis of HeLa and SiHa cells (p < 0.05) in HeLa and SiHa cell lines. CONCLUSION: The high expression of calcium channel TRPC6 in HeLa and SiHa tissues may be related to the malignant behavior of cervical cancer cell lines HeLa and SiHa. This calcium channel may be a new target for the prevention and treatment of cervical cancer.

TfOH-Catalyzed Cascade C-H/N-H Chemo-/Regioselective Annulation of Indole-2-carboxamides with Benzoquinones for the Construction of Anticancer Tetracyclic Indolo[2,3-c]quinolinones.

An efficient TfOH-catalyzed cascade C-H/N-H annulation of indole-2-carboxamides with benzoquinones has been developed for the synthesis of tetracyclic indolo[2,3-c]quinolinones. This reaction exhibits excellent chemo-/regioselectivity, achieving functionalization of the C-3 of indole and N-H of the amide moiety to form the new C-C and C-N bonds. Various expected products were synthesized from readily available starting materials in good to high yields with a wide substrate scope and good functional group tolerance. Among all synthetic products, 3d showed the most potent cytotoxicity toward the 4T1 cancer cell line with an IC50 value of 0.62 ± 0.05 µM. In vivo study demonstrated that 3d remarkably suppressed 4T1 xenograft tumor growth without body weight loss.

Discovery of honokiol thioethers containing 1,3,4-oxadiazole moieties as potential α-glucosidase and SARS-CoV-2 entry inhibitors.

Honokiol, isolated from a traditional Chinese medicine (TCM) Magnolia officinalis, is a biphenolic compound with several biological activities. To improve and broaden its biological activity, herein, two series of honokiol thioethers bearing 1,3,4-oxadiazole moieties were prepared and assessed for their α-glucosidase and SARS-CoV-2 entry inhibitory activities. Among all the honokiol thioethers, compound 7l exhibited the strongest α-glucosidase inhibitory effect with an IC50 value of 18.9 ± 2.3 µM, which was superior to the reference drug acarbose (IC50 = 24.4 ± 0.3 µM). Some interesting results of structure-activity relationships (SARs) have also been discussed. Enzyme kinetic study demonstrated that 7l was a noncompetitive α-glucosidase inhibitor, which was further supported by the results of molecular docking. Moreover, honokiol thioethers 7e, 9a, 9e, and 9r exhibited potent antiviral activity against SARS-CoV-2 pseudovirus entering into HEK-293 T-ACE2h. Especially 9a displayed the strongest inhibitory activity against SARS-CoV-2 pseudovirus entry with an IC50 value of 16.96 ± 2.45 µM, which was lower than the positive control Evans blue (21.98 ± 1.98 µM). Biolayer interferometry (BLI) binding and docking studies suggested that 9a and 9r may effectively block the binding of SARS-CoV-2 to the host ACE2 receptor through dual recognition of SARS-CoV-2 spike RBD and human ACE2. Additionally, the potent honokiol thioethers 7l, 9a, and 9r displayed relatively no cytotoxicity to normal cells (LO2). These findings will provide a theoretical basis for the discovery of honokiol derivatives as potential both α-glucosidase and SARS-CoV-2 entry inhibitors.

Monoterpene-flavonoid conjugates from Sarcandra glabra and their autophagy modulating activities.

Fourteen new monoterpene-flavonoid conjugates including four monoterpene-conjugated chalcones (glabratins A-D, 1-4), seven monoterpene-conjugated dihydrochalcones (glabratins E-K, 5-11), and three monoterpene-conjugated flavanones (glabratins L-N, 12-14), together with four known analogues (15-18) were isolated from the aerial parts of Sarcandra glabra. The structures and the absolute configurations of these compounds were elucidated by the spectroscopic data, single-crystal X-ray diffraction, and electronic circular dichroism (ECD) calculations. Compounds 1, 4-6, 9-14, and 18 showed obvious cell autophagy-inducing activities at 25 µM in HEK293 cells. Furthermore, the bioassay results also showed that 18 induced cell autophagy in a dose dependent manner. Our findings revealed a rare class of monoterpene-flavonoid conjugates in nature and firstly reported their autophagy-inducing activities.

Novel 1,3,4-thiadiazole/oxadiazole-linked honokiol derivatives suppress cancer via inducing PI3K/Akt/mTOR-dependent autophagy.

Honokiol is a bioactive biphenolic component derived from Magnoliae officinalis Cortex (known as "Hou Po" in Chinese), a traditional Chinese herbal medicine. A series of novel 1,3,4-thiadiazole/oxadiazole-linked honokiol derivatives were synthesized and tested for anticancer activity against seven human cancer cell lines in this study. Among all derivatives, 8a had the most potent cytotoxic effect on all tested cancer cells, with IC50 values ranging from 1.62 ± 0.19 to 4.61 ± 0.51 µM, which were 10.38-34.36 folds more potent than the parental honokiol (IC50 values of 30.96 ± 1.81-55.67 ± 0.31 µM). On A549, HCT116, and MDA-MB-231 cell lines, 8a demonstrated 5.69-fold, 5.65-fold, and 4.83-fold greater cytotoxicity than cisplatin, respectively. Compound 8a also had higher selectivity (SI values of 8.41-49.38) towards seven cancer cell lines over the normal cell lines than cisplatin (SI values of 1.24-2.52). The analysis of structure-activity relationships (SARs) revealed that honokiol derivatives bearing 1,3,4-thiadiazoles (8a-j) possessed stronger anticancer activity than those containing 1,3,4-oxadiazoles. Further mechanistic investigation indicated that 8a induced cytotoxic autophagy in cancer cells in a time- and dose-independent manner via suppressing the PI3K/Akt/mTOR pathway. Molecular docking suggested that 8a could bind to the PI3Kα active sites. Additionally, 8a inhibited the migration and invasion of A549 and MDA-MB-231 cancer cells.

Novel cinnamic acid magnolol derivatives as potent α-glucosidase and α-amylase inhibitors: Synthesis, in vitro and in silico studies.

In this study, twenty novel cinnamic acid magnolol derivatives were synthesized, and screened for their anti-hyperglycemic potential. All synthesized compounds exhibited good to moderate α-glucosidase and α-amylase inhibitory activities with IC50 values: 5.11 ± 1.46-90.26 ± 1.85 µM and 4.27 ± 1.51-49.28 ± 2.54 µM as compared to the standard acarbose (IC50: 255.44 ± 1.89 µM and 80.33 ± 2.95 µM, respectively). Compound 6j showed the strongest inhibitory activity against α-glucosidase (IC50 = 5.11 ± 1.46 µM) and α-amylase (IC50 = 4.27 ± 1.51 µM). Kinetic study indicated that compound 6j was reversible and a mixed type inhibitor against α-glucosidase and α-amylase. In silico studies revealed the binding interaction between 6j and two enzymes, respectively. Finally, cells cytotoxicity assay revealed that compound 6j showed low toxicity against 3 T3-L1 cells and HepG2 cells.

Non-classical cardenolides from Calotropis gigantea exhibit anticancer effect as HIF-1 inhibitors.

Six new non-classical cardenolides (1-6), and seventeen known ones (7-23) were isolated from Calotropis gigantea. All cardenolides showed inhibitory effect on hypoxia inducible factor-1 (HIF-1) transcriptional activity with IC50 of 8.85 nM-16.69 µM except 5 and 7. The novel 19-dihydrocalotoxin (1) exhibited a comparable HIF-1 inhibitory activity (IC50 of 139.57 nM) to digoxin (IC50 of 145.77 nM), a well-studied HIF-1 inhibitor, and 11, 12, 14, 16 and 19 presented 1.4-15.4 folds stronger HIF-1 inhibition than digoxin. 1 and 11 showed a dose-dependent inhibition on HIF-1α protein, which led to their HIF-1 suppressing effects. Compared with LO2 and H9c2 normal cell lines, both 1 and 11 showed selective cytotoxicity against various cancer cell lines including HCT116, HeLa, HepG2, A549, MCF-7, A2780 and MDA-MB-231. Moreover, a comprehensive structure-activity relationship was concluded for these non-classical cardenolides as HIF-1 inhibitors, which may shed some light on the rational design and development of cardenolide-based anticancer drugs.

Potent Antagonists of RORγt, Cardenolides from Calotropis gigantea, Exhibit Discrepant Effects on the Differentiation of T Lymphocyte Subsets.

RORγt is the master transcription factor of IL-17 cytokine expression and Th17 lymphocyte differentiation, which are responsible for the induction of many autoimmune diseases. Recently, RORγt has become an attractive target for drug development to treat these types of diseases, and the field of RORγt antagonist research is now extremely competitive. In our current study, molecular docking was applied to demonstrate that cardenolides, including uscharin, calactin, and calotropin derived from Calotropis gigantea, probably directly bind to RORγt. Therefore, the inhibitory effect was further validated using a luciferase reporter assay. Because RORγt is the key transcriptional factor for Th17 differentiation, the effects of these compounds on Th17 differentiation were studied by flow cytometry. The results showed that uscharin, calactin, and calotropin inhibited Th17 differentiation from 100 to 500 nM. Furthermore, uscharin had a better effect than digoxin, a well-known inverse agonist of RORγt, in reducing Th17 polarization. Additionally, the effects of the cardenolides on the differentiation of other Th lineages, including Th1, Th2, and Treg, were investigated. Uscharin suppressed Th1, Th2, and Treg cell differentiation, while calactin suppressed the differentiation of Th1 cells, and calotropin did not influence the other T cell subsets, indicating that calactin suppressed Th1 and Th17 differentiation, and calotropin selectively quenched Th17 polarization. Structural analysis of the three compounds showed that the selectivity of uscharin, calactin, and calotropin on the suppression of the different subsets of T cells is correlated to the minor differences in their chemical structures. Collectively, calactin and calotropin have greater potential to be developed as lead compounds than uscharin to treat autoimmune diseases mediated by Th17 and/or Th1 cells.

Identification of an IKKß inhibitor for inhibition of inflammation in vivo and in vitro.

Targeting on the IKKß to discover anti-inflammatory drugs has been launched for ten years, due to its predominant role in canonical NF-κB signaling. In the current study, we identified a novel IKKß inhibitor, ellipticine (ELL), an alkaloid isolated from Ochrosia elliptica and Rauvolfia sandwicensis. We found that ELL reduced the secretion and mRNA expression of TNF-α and IL-6 and decreased the protein expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in bone marrow derived macrophages (BMDMs) stimulated with LPS. In coincided with the results, ELL suppressed PGE2 and NO production in BMDMs. Underlying mechanistic study showed that ELL inhibited IκBα phosphorylation and degradation as well as NF-κB nuclear translocation, which was attributed to suppression of IKKα/ß activation. Furthermore, kinase assay and binding assay results indicated that ELL inhibited IKKß activity via directly binding to IKKß and in turn resulted in suppression of NF-κB signaling. To identify the binding sites of ELL on IKKß, IKKßC46A plasmid was prepared and the kinase assay was performed. The results demonstrated that the inhibitory effect of ELL on IKKß activity was impaired in the mutation, implying that anti-inflammatory effect of ELL was partially attributed to binding on cysteine 46. Furthermore, ELL up-regulated LC3 II expression and reduced p62 expression, suggesting that autophagy induction contributed to the anti-inflammatory effect of ELL as well. In coincided with the in vitro results, ELL increased the survival and antagonized the hypothermia in the mice with LPS-induced septic shock. Consistently, ELL reduced TNF-α and IL-6 production in the serum of the mice treated with LPS. Collectively, our study provides evidence that ELL is an IKKß inhibitor and has potential to be developed as a lead compound for treatment inflammatory diseases in the future.

Linderalides A-D, Disesquiterpenoid-Geranylbenzofuranone Conjugates from Lindera aggregata.

Four disesquiterpenoid-geranylbenzofuranone conjugates, linderalides A-D (1-4), were isolated from Lindera aggregata. Compounds 1-3 represent the first examples of disesquiterpenoid-geranylbenzofuranone hybrids directly linked by two C-C bonds. Linderalide D (4) bears an unprecedented carbon skeleton featuring an unusual linearly 6/6/5/6/6 pentacyclic ring system fused by a sesquiterpenoid unit and a geranylbenzofuranone moiety. Their structures and absolute configurations were elucidated by extensive spectroscopic data and electronic circular dichroism analysis. Their biosynthetic pathways were also proposed.

Novel dauricine derivatives suppress cancer via autophagy-dependent cell death.

Eleven dauricine derivatives were synthesized and evaluated for their anti-cancer effect in different cancer cells and their autophagic activity in HeLa model cell. Among these newly synthesized compounds, carbamates 2a, 2b, carbonyl ester 3a and sulfonyl ester 4a exhibited potent cytotoxic effects on tested cancer cells with IC50 values ranged from 2.72 to 12.53 µM, which were more potent than that of dauricine (higher than 15.53 µM). The above four derivatives are validated to induce autophagy-dependent cell death in HeLa cancer cells. These findings offer us a promising source for generating novel autophagic enhancers for anti-cancer therapy.

[Risk Factors Associated with Intraoperative Blood Loss in Patients with Early Cervical Cancer].

OBJECTIVE: To determine risk factors associated with intraoperative blood loss in patients with early cervical cancer (stage ⅠB-ⅡA). METHODS: The medical records of 892 patients who underwent surgical treatments for early cervical cancer in the Second West China University Hospital of from Dec 2010 to Sep 2017 were retrospectively reviewed: 127 having ≥500 mL intraoperative blood loss patients compared with 765 less than 500 mL. Differences between the two groups in age, body mass index (BMI), gravidity, history of abdominal and pelvic operations, chronic pelvic inflammation disease, clinical stage, methods of operation, neoadjuvant chemotherapy (NACT) and post-NACT operative opportunity, preoperative and postoperative hemoglobin, and intraoperative transfusion volume were analyzed through univariate and multivariate statistical methods. RESULTS: The univariate analyses identified age, BMI, gravidity, history of abdominal and pelvic operation, chronic pelvic inflammation disease, clinical stage, methods of operation, NACT and post-NACT operative opportunity assignificant factors associated with intraoperative blood loss ( P<0.05). The multivariate logistic regression analysis confirmed that age ≥40 yr. [partial regression coefficient (B)=2.100)], BMI ≥24 kg/m2 (relative to 18.5-23.9 kg/m2)(B=1.842) , clinical stage ⅡA (relative to phase ⅠB, B=2.401) , trans-abdominal operative method (relative to laparoscopy, B=1.347), no NACT (B=1.540) and post-NACT operative opportunity <2 or >3 weeks (relative to within 2-3 weeks) (B=1.723) were independent predictors of higher intraoperative blood loss (≥500 mL). CONCLUSION: Clinical stage and age, etc. are risk factors associated with intraoperative blood loss in patients with early cervical cancer.

(±)-Sativamides A and B, Two Pairs of Racemic Nor-Lignanamide Enantiomers from the Fruits of Cannabis sativa.

(±)-Sativamides A (1) and B (2), two pairs of nor-lignanamide enantiomers featuring a unique benzo-angular triquinane skeleton, were isolated from the fruits of Cannabis sativa (hemp seed). Their structures were elucidated by detailed spectroscopic analysis and ECD calculations. The resolution of (+)- and (-)-sativamides A and B were achieved by chiral HPLC. Pretreatment of neuroblastoma cells with 1 and 2 significantly reduced the endoplasmic reticulum (ER) stress-induced cytotoxicity.

Lanthanum-Based Metal-Organic Frameworks for Specific Detection of Sudan Virus RNA Conservative Sequences down to Single-Base Mismatch.

Reactions of La(NO3)3·6H2O with the polar, tritopic quaternized carboxylate ligands N-carboxymethyl-3,5-dicarboxylpyridinium bromide (H3CmdcpBr) and N-(4-carboxybenzyl)-3,5-dicarboxylpyridinium bromide (H3CbdcpBr) afford two water-stable metal-organic frameworks (MOFs) of {[La4(Cmdcp)6(H2O)9]}n (1, 3D) and {[La2(Cbdcp)3(H2O)10]}n (2, 2D). MOFs 1 and 2 absorb the carboxyfluorescein (FAM)-tagged probe DNA (P-DNA) and quench the fluorescence of FAM via a photoinduced electron transfer (PET) process. The nonemissive P-DNA@MOF hybrids thus formed in turn function as sensing platforms to distinguish conservative linear, single-stranded RNA sequences of Sudan virus with high selectivity and low detection limits of 112 and 67 pM, respectively (at a signal-to-noise ratio of 3). These hybrids also exhibit high specificity and discriminate down to single-base mismatch RNA sequences.