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PREMISE The distribution and performance of bryophyte species vary with vertical gradients, as a result of changes in environmental factors, especially light. However, the morphological and physiological drivers of bryophyte distribution along forest vertical gradients are poorly understood. METHODS For 18 species of mosses and liverworts distributed among three vertical microhabitats (ground, tree trunk, and branch, variance in 28 morphological and photosynthetic functional traits was comparatively analyzed among the microhabitats and bryophyte life-forms in a subtropical cloud forest in Ailao Mountain, Yunnan, southwestern China. Principal component analysis (PCA) was used to summarize trait differences among bryophyte species. RESULTS In contrast to trunk and ground dwellers, branch dwellers tended to reduce light interception (smaller leaf and cell sizes, lower chlorophyll content), protect against damage from intense irradiation (higher ratios of carotenoids to chlorophyll), raise light energy use (higher photosynthetic capacity), and cope with lower environmental moisture (pendant life-forms, thicker cell walls). The PCA showed that ecological strategies of bryophytes in response to levels of irradiation were specialized in branch dwellers, although those of ground and trunk dwellers were less distinct. CONCLUSIONS Environmental filtering shaped the combination of functional traits and the spatial distribution of bryophytes along the vertical gradients. Bryophyte species from the upper canopy of cloud forests show narrow variation in functional traits in high-light intensity, whereas species in the lower vertical strata associated with low-light intensity used contrasting, but more diverse ecological strategies.

Chlorophyll content in lichens is routinely used as an accurate indicator of lichen vigor, interspecific differences, and the effect of site-related environmental parameters. Traditional methods of chlorophyll extraction are destructive, time-consuming, expensive, and inoperable, especially when measuring large quantities of chlorophyll. However, non-destructive methods of measurement using portable chlorophyll meters are rarely used for lichens. Considering the characteristics of lichens such as rough blade surface and absence of chlorophyll b in cyanolichens, we compared the non-destructive methods with traditional methods and evaluated their applicability in studying lichen pigment content. Two instruments, SPAD-502 and CCM-300, were used to measure the pigment content of seven foliose lichen species. These pigment readings were compared with those determined using the dimethyl sulphoxide (DMSO) extraction method. Significant correlations were observed between SPAD/CCM values and pigments (chlorophyll and total carotenoids) extracted from chlorolichens, especially species with a smooth surface. The CCM-300 was more accurate in detecting the pigment content of foliose chlorolichens. However, both instruments showed certain limitations in the determination of pigment content in cyanolichens, especially gelatinous species. For example, CCM-300 often failed to give specific values for some cyanolichen samples, and both instruments showed low measurement accuracy for cyanolichens. Based on the high correlation observed between chlorophyll meter readings and pigments extracted from chlorolichens, equations obtained in this study enabled accurate prediction of pigment content in these lichens.

The application of patient-derived xenografts (PDX) in drug screening and testing is a costly and time-consuming endeavor. While cell lines permit extensive mechanistic studies, many human breast cancer cell lines lack patient characteristics and clinical treatment information. Establishing cell lines that retain patient’s genetic and drug response information would enable greater drug screening and mechanistic studies. Therefore, we utilized breast cancer PDX from the Mayo Breast Cancer Genome Guided Therapy Study (BEAUTY) to establish two immortalized, genomically unique breast cancer cell lines. Through extensive genetic and therapeutic testing, the cell lines were found to retain the same clinical subtype, major somatic alterations, and drug response phenotypes as their corresponding PDX and patient tumor. Our findings demonstrate PDX can be utilized to develop immortalized breast cancer cell lines and provide a valuable tool for understanding the molecular mechanism of drug resistance and exploring novel treatment strategies.

In order to clarify the mitochondrial toxicity mechanism of the organic arsenical MOPIMP (2-methoxy-4-(((4-(oxoarsanyl) phenyl) imino) methyl) phenol), research was carried out at the sub-cell level based on the previous finding that the compound MOPIMP can damage the mitochondria by triggering a burst of ROS. After investigating its influence on isolated mitochondria in vitro, it was demonstrated that a high dose of MOPIMP with short-term exposure can induce mitochondrial swelling, decrease the membrane potential, enhance the permeability of H+ and K+, and induce membrane lipid peroxidation, indicating that it can result in an MPT process in a ROS-mediated and Ca2+-independent manner. Additionally, MPT was also aggravated as a result of impairment of the membrane integrity and membrane fluidity. In addition, short-term incubation between mitochondria and compound MOPIMP promoted the inhibition of respiratory chain complexes I, II, III and IV, as well as damage to the respiration process, which supported the previous finding about the burst of ROS. On the other hand, after long-term exposure by the organic arsenical MOPIMP, mitochondrial metabolic dysfunction was triggered, which was in accordance with perturbation of the respiratory chain complexes as well as the respiration process. This work systematically sheds light on the mitochondrial toxicity mechanism of the organic arsenical MOPIMP, including induction of the MPT process and inhibition of respiratory metabolism, which provides a potential target for organic arsenicals as anti-tumor drugs.

Considering the vital role of cellular redox state, more and more researches focus on the design of drugs targeting thioredoxin reductase (TrxR), an important enzyme in maintaining the balance of cellular redox. Here two organic arsenicals, 2-(((4-(1,3,2-dithiarsinan-2-yl) phenyl) imino) methyl) phenol (PIM-PAO-PDT) and N-(4-(1,3,2-dithiarsinan-2-yl) phenyl)-2-hydroxybenzamide (PAM-PAO-PDT), bearing the S-As-S chemical scaffold and different linking groups have been synthesized, and both of them show the better inhibitory activity and selectivity towards HL-60 cells. Importantly, it is illustrated that they can target TrxR selectively and inhibit its activity via the disturbance for Cys83 and Cys88 located in conserved active sites. Afterwards, the cells suffer from the burst of ROS, consumption of antioxidants and high sensitivity for oxidants, which further damage the mitochondria leading to dysfunction including the collapse of membrane potential, ATP level decline, mitochondrial membrane swelling, MPTP opening, Ca2+ and cytochrome c release. Then the mitochondria-dependent apoptosis is triggered by PIM-PAO-PDT and PAM-PAO-PDT, which can also be deterred in the presence of NAC, DTT or LA. Although the organic arsenicals can suppress TrxR activity, the following oxidative stress and mitochondrial dysfunction are the main causes for apoptosis.

As a novel delocalized lipophilic cation, F16 selectively accumulates in mitochondria of carcinoma cells and shows a broad spectrum of antiproliferative action towards cancer cell lines. In order to reveal the mode of action and molecular mechanism of F16 inducing cytotoxicity, we investigated the effects of F16 on cancer cells and isolated mitochondria relative to its precursor compound (E)-3-(2-(pyridine-4yl)vinyl)-1 H-indole (PVI), which has a similar structure without positive charge. It was found that PVI did not accumulate in mitochondria, and exhibited lower cytotoxicity compared to F16. However, when they were directly incubated with mitochondria, both F16 and PVI were observed to induce damage to mitochondrial structure and function. Moreover, it was found that F16 as well as PVI acted as uncouplers on mitochondria, and further rescue experiments revealed that the addition of adenosine 5'-triphosphate was the most effective way to recover the cell viability decreased by F16. Thus it was concluded that the decreased intracellular adenosine 5'-triphosphate availability induced by the uncoupling effect of F16 was a major factor in F16-mediated cytotoxicity. Futhermore, the results indicated that the uncoupling effect of F16 is attributed to its chemical stucture in common with PVI but independent of its positive charge. The study may shed light on understanding the underlying mechanism of action for F16, and providing suggestions for the design of new mitochondria-targeted antitumor molecules.

Based on the potential therapeutic value in targeting mitochondria and the fluorophore tracing ability, a fluorescent mitochondria-targeted organic arsenical PDT-PAO-F16 was fabricated, which not only visualized the cellular distribution, but also exerted anti-cancer activity in vitro and in vivo via targeting pyruvate dehydrogenase complex (PDHC) and respiratory chain complexes in mitochondria. In details, PDT-PAO-F16 mainly accumulated into mitochondria within hours and suppressed the activity of PDHC resulting in the inhibition of ATP synthesis and thermogenesis disorder. Moreover, the suppression of respiratory chain complex I and IV accelerated the mitochondrial dysfunction leading to caspase family-dependent apoptosis. In vivo, the acute promyelocytic leukemia was greatly alleviated in the PDT-PAO-F16 treated group in APL mice model. Our results demonstrated the organic arsenical precursor with fluorescence imaging and target-anticancer efficacy is a promising anticancer drug.

A simple acylhydrazone derivative 4-chloro-N′-(pyridin-2-ylmethylene) benzo- hydrazide (CPBH) has been designed to be a fluorescence probe for Al3+. CPBH displays a highly sensitive and selective fluorescence enhancement with Al3+ among various metal ions, due to a reduced intramolecular charge transfer and chelation enhanced fluorescence mechanism. The limit of dection for Al3+ is 0.2 μM (5.4 ppb), and the linear range is from 2 to 15 μM (50–400 ppb, c(CPBH) = 20 μM) in the low concentration while another linear range is from 20 to 80 μM (540–2200 ppb, c(CPBH) = 100 μM). The CPBH and Al3+ form a 2:1 coordination complex according to the ESI-MS, Job plots and spectroscopy data. The binding equilibrium constant K is about 4.69 × 104 M−1 and 3.68 × 104 M−1 based on the data from absorption and emission spectra, respectively. To conclude, CPBH can be used as a sensitive and selective fluorescent probe for Al3+.

Considering the vital role of mitochondria in the anti-cancer mechanism of organic arsenical, the mitochondria-targeted precursor PDT-PAO-TPP was designed and synthesized. PDT-PAO-TPP, as a delocalization lipophilic cation (DLCs) which mainly accumulated in mitochondria, contributed to improve anti-cancer efficacy and selectivity towards NB4 cells. In detail, PDT-PAO-TPP inhibited the activity of PDHC resulting in the suppression of ATP synthesis and thermogenesis disorder. Additionally, the inhibition of respiratory chain complex I and IV by short-time incubation of PDT-PAO-TPP also accelerated the respiration dysfunction and continuous generation of ROS. These results led to the release of cytochrome c and activation of caspase family-dependent apoptosis. Different from the mechanism of PDT-PAO in HL-60 cells, it mainly induced the mitochondrial metabolic disturbance resulting in the intrinsic apoptosis via inhibiting the activity of PDHC in NB4 cells, which also implied that the efficacy exertion of organic arsenical was a complex process involved in many aspects of cellular function. This study systematically clarifies the anti-cancer mechanism of mitochondria-targeted organic arsenical PDT-PAO-TPP and confirms the new target PDHC of organic arsenicals, which further supports the organic arsenical as a promising anticancer drug.

A highly sensitive and selective Rhodamine B-based fluorescent sensor, RhB-1, for glutathione (GSH) was easily synthesized. An extremely fast detection response time of 10 s, which is the fastest one ever reported, is achieved in aqueous solutions over a wide pH range with large enhancement of emission intensity. The sensor detects GSH in cells and selectively accumulates in lysosomes.

5-Fluorouracil (5-FU) was linked with F16 by vulnerable bonds to selectively target cancer mitochondria which resulted in conjugated compounds, including F16–5-FU, F16–OOC-FU, F16–NHOC-FU and F16–SS-FU. F16–OOC-FU decreased the antiproliferative activity of 5-FU on the nontumor cell line, and the cytotoxicity of F16–SS-FU significantly increased when administered with dithiothreitol (DTT).

Icariin is a flavonol glycoside with a wide range of pharmacological and biological activities. The pharmacological and biological functions of flavonoid compounds mainly originate from their binding to proteins. The mode of interaction of icariin with human serum albumin (HSA) has been characterized by fluorescence spectroscopy and far- and near-UV circular dichroism (CD) spectroscopy under different pH conditions. Fluorescence quenching studies showed that the binding affinity of icariin with HSA in the buffer solution at different pH values is: Ka (pH 4.5) > Ka (pH 3.5) > Ka (pH 9.0) > Ka (pH 7.0). Red-edge excitation shift (REES) studies revealed that pH had an obvious effect on the mobility of the tryptophan microenvironment and the addition of icariin made the REES effect more distinct. The static quenching mechanism and number of binding sites (n ≈ 1) were obtained from fluorescence data at three temperatures (298, 304 and 310 K). Both ∆H0 < 0 and ∆Ѕ0 < 0 suggested that hydrogen bonding and van der Waal's interaction were major driving forces in the binding mechanism, and this was also confirmed by the molecular simulation results. The distance r between the donor (HSA) and the acceptor (icariin) was calculated based on Forster non-radiation energy transfer theory. We found that pH had little impact on the energy transfer between HSA and icariin. Far- and near-UV CD spectroscopy studies further indicated the influence of pH on the complexation process and the alteration in the protein conformation upon binding. Copyright © 2015 John Wiley & Sons, Ltd.

Based on the potential therapeutic value in targeting metabolism for the treatment of cancer, an organic arsenical PDT-BIPA was fabricated, which exerted selective anti-cancer activity in vitro and in vivo via targeting lactate dehydrogenase A (LDHA) to remodel the metabolic pathway. In details, the precursor PDT-BIPA directly inhibited the function of LDHA and converted the glycolysis to oxidative phosphorylation causing ROS burst and mitochondrial dysfunction. PDT-BIPA also altered several gene expression, such as HIF-1&alpha, and C-myc, to support the metabolic remodeling. All these changes lead to caspase family-dependent cell apoptosis in vivo and in vitro without obvious side effect. Our results provided this organic arsenical precursor as a promising anticancer candidate and suggested metabolism as a target for cancer therapies.

Investigation of interaction between rotenone (Rot) and human serum albumin (HSA) is provided. Fluorescence, UV–visible absorption, circular dichroism (CD), and molecular docking methods have been utilized to study the interaction. The static fluorescence quenching was observed and the binding site of Rot–HSA was shown near the warfarin site. The association for Rot and HSA was spontaneous process driven by enthalpy and the dominant driving force was hydrogen bonding interaction. The result was accordant with the molecular docking result. Furthermore, the microenvironment of tyrosine residue was influenced by the binding of rotenone via the synchronous fluorescence spectra. However, Rot had little effect on the conformation of HSA, which supported by the CD method and 3D-fluorescence spectra. Taking all of results into consideration, we conclude Rot changes the conformation of HSA slightly.

This paper exploring the site-selective binding of jatrorrhizine to human serum albumin (HSA) under physiological conditions (pH = 7.4). The investigation was carried out using fluorescence spectroscopy, UV–vis spectroscopy, and molecular modeling. The results of fluorescence quenching and UV–vis absorption spectra experiments indicated the formation of the complex of HSA–jatrorrhizine. Binding parameters calculating from Stern–Volmer method and Scatchard method were calculated at 298, 304 and 310 K, with the corresponding thermodynamic parameters ΔG, ΔH and ΔS as well. Binding parameters calculating from Stern–Volmer method and Scatchard method showed that jatrorrhizine bind to HSA with the binding affinities of the order 104 L mol−1. The thermodynamic parameters studies revealed that the binding was characterized by negative enthalpy and positive entropy changes and the electrostatic interactions play a major role for jatrorrhizine–HSA association. Site marker competitive displacement experiments and molecular modeling calculation demonstrating that jatrorrhizine is mainly located within the hydrophobic pocket of the subdomain IIIA of HSA. Furthermore, the synchronous fluorescence spectra suggested that the association between jatrorrhizine and HSA changed molecular conformation of HSA.

Cationic porphyrins are potential antiprion drugs; however, the action mechanisms remain poorly understood. Herein, the interaction between a cationic porphyrin and recombinant human prion protein (rPrP C ) was comprehensively studied by using surface plasmon resonance (SPR), fluorescence, resonance light scattering (RLS), and circular dichroism (CD) spectroscopy. The experimental results showed that the interaction between the cationic porphyrin and rPrP C was pH dependent. The equilibrium association constants obtained from SPR spectroscopy were 4.12 × 10 3 M − 1 at pH 4.0, 1.74 × 10 5 M − 1 at pH 6.0, and 5.98 × 10 5 M − 1 at pH 7.0. The binding constants at 298 K obtained from the fluorescence quenching method were 7.286 × 10 4 M − 1 at pH 4.0 and 1.45 7 × 10 5 M − 1 at pH 6.0. The thermodynamic parameters such as enthalpy change, entropy change, and free energy change were calculated, and the results indicated hydrogen bonds and van der Waals interactions played a major role in the binding reaction. The RLS experiment was performed to study the influence of porphyrin on the rPrP C aggregation at different pH values. The CD experiments were conducted to investigate the effects of porphyrin on the secondary structure and thermal stability of rPrP C . Finally, the comparison of SPR measurement and fluorescence quenching measurement was discussed.

Arsenic trioxide has shown the excellent therapeutic efficiency for acute promyelocytic leukemia. Nowadays, more and more research focuses on the design of the arsenic drugs, especially organic arsenicals, and on the mechanism of the inducing cell death. Here we have synthesized some organic arsenicals with Schiff base structure, which showed a better antitumor activity for three different kinds of cancer cell lines, namely HL-60, SGC 7901 and MCF-7. Compound 2a (2-(((4-(oxoarsanyl)phenyl)imino)methyl)phenol) and 2b (2-methoxy-4-(((4-(oxoarsanyl)phenyl)imino)methyl)phenol) were chosen for further mechanism study due to their best inhibitory activities for HL-60 cells, of which the half inhibitory concentration (IC50) were 0.77 μM and 0.51 μM, respectively. It was illustrated that 2a or 2b primarily induced the elevation of reactive oxygen species, decrease of glutathione level, collapse of mitochondrial membrane potential, release of cytochrome c, activation of Caspase-3 and apoptosis, whereas all of the phenomena can be eliminated by the addition of antioxidants. Therefore, we concluded that compound 2a and 2b can induce the oxidative stress-mediated intrinsic apoptosis in HL-60 cells. Both the simplicity of structure with Schiff base group and the better anticancer efficiency demonstrate that organic arsenicals are worthy of further exploration as a class of potent antitumor drugs.

The interaction between jatrorrhizine (JAT) and bovine serum albumin (BSA) has been studied. The studies were carried out in a buffer medium at pH 7.4 using fluorescence spectroscopy, UV–vis spectroscopy, and molecular modeling methods. The results of fluorescence quenching and UV–vis absorption spectra experiments indicated the formation of the complex of BSA–JAT. Binding parameters were determined using the Stern–Volmer equation and Scatchard equation. The results of thermodynamic parameters ΔG, ΔH and ΔS at different temperatures indicate that the electrostatic interactions and hydrogen bonds play a major role for JAT–BSA association. Site marker competitive displacement experiments and molecular modeling calculation demonstrating that JAT is mainly located within the hydrophobic pocket of the subdomain IIIA of BSA. Furthermore, The distance between donor (BSA) and acceptor (JAT) was estimated according to fluorescence resonance energy transfer.