Palladium-Catalyzed Cascade Endo-dig Cycloisomerization and Olefination with Alkenes to Access Fused Oxatricyclic Compounds

A novel cascade Pd(II)-catalyzed endo-dig cycloisomerization and olefination reaction of 2-benzyl-3-alkynyl chromones with activated/unactivated alkenes has been developed for the synthesis of fused oxatricyclic compounds. This concise one-pot synthetic approach was applied to the difunctionalization of unbiased alkynes based on 2-benzyl-3-(alkynyl)-4H-chromen-4-one via O-attack endo-dig cycloisomerization, followed by olefination with both activated and unactivated alkenes.

Isolation of Anti-SARS-CoV-2 Natural Products Extracted from Mentha canadensis and the Semi-synthesis of Antiviral Derivatives

Traditional herbal medicine offers opportunities to discover novel therapeutics against SARS-CoV-2 mutation. The dried aerial part of mint (Mentha canadensis L.) was chosen for bioactivity-guided extraction. Seven constituents were isolated and characterized by nuclear magnetic resonance (NMR) and mass spectrometry (MS). Syringic acid and methyl rosmarinate were evaluated in drug combination treatment. Ten amide derivatives of methyl rosmarinate were synthesized, and the dodecyl (13) and 3-ethylphenyl (19) derivatives demonstrated significant improvement in the anti-SARS-CoV-2 plaque reduction assay, achieving IC50 of 0.77 and 2.70 μM, respectively, against Omicron BA.1 as compared to methyl rosmarinate's IC50 of 57.0 μM. Spike protein binding and 3CLpro inhibition assays were performed to explore the viral inhibition mechanism. Molecular docking of compounds 13 and 19 to 3CLpro was performed to reveal potential interaction. In summary, natural products with anti-Omicron BA.1 activity were isolated from Mentha canadensis and derivatives of methyl rosmarinate were synthesized, showing 21- to 74-fold improvement in antiviral activity against Omicron BA.1.

NRICM101 ameliorates SARS-CoV-2-S1-induced pulmonary injury in K18-hACE2 mice model

The coronavirus disease 2019 (COVID-19) pandemic continues to represent a challenge for public health globally since transmission of different variants of the virus does not seem to be effectively affected by the current treatments and vaccines. During COVID-19 the outbreak in Taiwan, the patients with mild symptoms were improved after the treatment with NRICM101, a traditional Chinese medicine formula developed by our institute. Here, we investigated the effect and mechanism of action of NRICM101 on improval of COVID-19-induced pulmonary injury using S1 subunit of the SARS-CoV-2 spike protein-induced diffuse alveolar damage (DAD) of hACE2 transgenic mice. The S1 protein induced significant pulmonary injury with the hallmarks of DAD (strong exudation, interstitial and intra-alveolar edema, hyaline membranes, abnormal pneumocyte apoptosis, strong leukocyte infiltration, and cytokine production). NRICM101 effectively reduced all of these hallmarks. We then used next-generation sequencing assays to identify 193 genes that were differentially expressed in the S1+NRICM101 group. Of these, three (Ddit4, Ikbke, Tnfaip3) were significantly represented in the top 30 enriched downregulated gene ontology (GO) terms in the S1+NRICM101 group versus the S1+saline group. These terms included the innate immune response, pattern recognition receptor (PRR), and Toll-like receptor signaling pathways. We found that NRICM101 disrupted the interaction of the spike protein of various SARS-CoV-2 variants with the human ACE2 receptor. It also suppressed the expression of cytokines IL-1β, IL-6, TNF-α, MIP-1β, IP-10, and MIP-1α in alveolar macrophages activated by lipopolysaccharide. We conclude that NRICM101 effectively protects against SARS-CoV-2-S1-induced pulmonary injury via modulation of the innate immune response, pattern recognition receptor, and Toll-like receptor signaling pathways to ameliorate DAD.

Targeting spike protein-induced TLR/NET axis by COVID-19 therapeutic NRICM102 ameliorates pulmonary embolism and fibrosis

The global COVID-19 pandemic remains a critical public health threat, as existing vaccines and drugs appear insufficient to halt the rapid transmission. During an outbreak from May to August 2021 in Taiwan, patients with severe COVID-19 were administered NRICM102, which was a traditional Chinese medicine (TCM) formula developed based on its predecessor NRICM101 approved for treating mild cases. This study aimed to explore the mechanism of NRICM102 in ameliorating severe COVID-19-related embolic and fibrotic pulmonary injury. NRICM102 was found to disrupt spike protein/ACE2 interaction, 3CL protease activity, reduce activation of neutrophils, monocytes and expression of cytokines (TNF-α, IL-1β, IL-6, IL-8), chemokines (MCP-1, MIP-1, RANTES) and proinflammatory receptor (TLR4). NRICM102 also inhibited the spread of virus and progression to embolic and fibrotic pulmonary injury through reducing prothrombotic (vWF, PAI-1, NET) and fibrotic (c-Kit, SCF) factors, and reducing alveolar type I (AT1) and type II (AT2) cell apoptosis. NRICM102 may exhibit its protective capability via regulation of TLRs, JAK/STAT, PI3K/AKT, and NET signaling pathways. The study demonstrates the ability of NRICM102 to ameliorate severe COVID-19-related embolic and fibrotic pulmonary injury in vitro and in vivo and elucidates the underlying mechanisms.

Triterpene Acids from Mesona procumbens Exert Anti-inflammatory Effects on LPS-Stimulated Murine Macrophages by Regulating the MAPK Signaling Pathway

Five new triterpene acids, mesonaic acids A-C (1-3), 2α,3α,19α-trihydroxy-24-nor-4(23),12-oleanadien-28-oic acid (4), and 3α,19α,22α-trihydroxy-2-oxo-12-ursen-28-oic acid (5), and 10 known triterpene acid compounds (6-15) were isolated from a methanolic extract of Mesona procumbens. Triterpenes 1-3 possess unusual hexacyclic skeletons with a 13α,27-cyclopropane ring. Regarding their anti-inflammatory activity, compounds 1-3, 6, and 7 inhibited NO production with EC₅₀ values lower than 15 μM, which were better than that of the positive control quercetin. Compounds 1-3, 6, and 7 markedly decreased levels of the inducible iNOS and COX-2 proteins in macrophages by inhibiting the activation of NF-κB through interference with the MAPK signaling pathway. Based on these data, compounds 1-3, 6, and 7 have great potential as NO inhibitors.

Huang Lian Jie Du Tang attenuates paraquat-induced mitophagy in human SH-SY5Y cells: A traditional decoction with a novel therapeutic potential in treating Parkinson's disease

Huang Lian Jie Du Tang (HLJDT) is a traditional Chinese medical decoction for heat-fire clearing and detoxication. Theoretically, the cause of Parkinson's disease (PD) has been attributed to the dysregulations of internal wind, phlegm, fire, and stasis. Thus, HLJDT has been used to treat PD. However, the molecular mechanism is unknown. Besides, paraquat (PQ) as an herbicide has been known to impair midbrain dopaminergic neurons, resemblance to the pathology of PD. Thus, the molecular mechanism of HLJDT in treating PD and PQ-induced in vitro PD model was investigated in this study. Primarily, the dose-response of PQ (0.1∼1 mM)-induced neurotoxicity for 24 h was performed in the human neuroblastoma SH-SY5Y cells. The LD₅₀ of PQ is around 0.3 mM and was applied throughout the following experiments. The neutral red assay was used to estimate cell viability. Co-transfection of the mitochondrial marker and proapoptotic factor genes were applied to measure the release of mitochondrial proapoptotic factors during PQ intoxication and HLJDT protection. The fluorescent dyes were used to detect mitochondrial membrane potential and free radical formation. Western blot and dot-blot analysis and immunocytochemistry were used to estimate the level of proteins related to apoptosis and mitophagy. PINK1 gene silencing was used to determine the significance of mitophagy during PQ intoxication. In this study, HLJDT attenuated PQ-induced apoptosis in SH-SY5Y cells. HLJDT reversed PQ-induced decreased mitochondrial membrane potential and suppressed PQ-induced increased cytosolic and mitochondrial free radical formations and mitochondrial proapoptotic factor releases. Furthermore, HLJDT mitigated PQ-induced increases in full-length PINK1, phosphorylations of Parkin and ubiquitin, mitochondrial translocation of phosphorylated Parkin, and mitophagy. PINK1 gene silencing attenuated PQ-induced neurotoxicity. Therefore, HLJDT attenuated PQ-induced cell death by regulating mitophagy.

A traditional Chinese medicine formula NRICM101 to target COVID-19 through multiple pathways: A bedside-to-bench study

COVID-19 is a global pandemic, with over 50 million confirmed cases and 1.2 million deaths as of November 11, 2020. No therapies or vaccines so far are recommended to treat or prevent the new coronavirus. A novel traditional Chinese medicine formula, Taiwan Chingguan Yihau (NRICM101), has been administered to patients with COVID-19 in Taiwan since April 2020. Its clinical outcomes and pharmacology have been evaluated. Among 33 patients with confirmed COVID-19 admitted in two medical centers, those (n = 12) who were older, sicker, with more co-existing conditions and showing no improvement after 21 days of hospitalization were given NRICM101. They achieved 3 consecutive negative results within a median of 9 days and reported no adverse events. Pharmacological assays demonstrated the effects of the formula in inhibiting the spike protein/ACE2 interaction, 3CL protease activity, viral plaque formation, and production of cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α. This bedside-to-bench study suggests that NRICM101 may disrupt disease progression through its antiviral and anti-inflammatory properties, offering promise as a multi-target agent for the prevention and treatment of COVID-19.

Morphological control of mitochondria as the novel mechanism of Gastrodia elata in attenuating mutant huntingtin-induced protein aggregations

BACKGROUND

According to Compendium of Materia Medica, Gastrodia elata (GE) Blume as a top grade and frequently prescribed herbal medicine has been used in treating dizziness, headaches, and epilepsy, indicating a neuroprotective effect. Because GE is capable of suppressing a hyperactive liver and thus calming endogenous wind, and because Huntington's disease (HD) can be classified as a phenomenon of disturbed liver wind, it is suggested that GE might be beneficial in treating HD. However, although current studies support GE for the prevention of diverse neurodegenerations such as HD, its detailed mechanisms remain elusive.

PURPOSE

To investigate the molecular mechanism of GE in preventing HD by focusing on mitochondrial morphology, which is highly associated with HD etiology and thus proposed as a therapeutic target of neurodegenerations.

STUDY DESIGN/METHODS

The overexpression of the mutant huntingtin (mHTT) gene in rat pheochromocytoma (PC12) cells was used as an in vitro cell model of HD. A filter retardation assay was applied to measure protein aggregations during HTT expression. Cotransfection with mitochondrial fusion and fission genes was used to test their relationships with HTT aggregates by monitoring with a confocal laser scanning microscope and filter retardation assay. Western blot analysis was used to estimate protein expression under different drug treatments or cotransfections with other related genes.

RESULTS

The overexpression of mutant but not normal HTT genes significantly resulted in protein aggregations in PC12 cells. GE dose-dependently attenuated mHTT-induced protein aggregations and free radical formations. GE significantly reversed mHTT-induced mitochondrial fragmentation and dysregulation of mitochondrial fusion and fission molecules. The overexpression of mitochondrial fusion genes attenuated mHTT-induced protein aggregations. Further, Mdivi-1, a DRP1 fission molecule inhibitor, significantly reversed mHTT-induced protein aggregations and mitochondrial fragmentation.

CONCLUSION

GE attenuated mHTT aggregations through the control of mitochondrial fusion and the fission pathway.

LGK974, a PORCUPINE inhibitor, mitigates cytotoxicity in an in vitro model of Parkinson's disease by interfering with the WNT/β-CATENIN pathway

Paraquat (PQ) as an herbicide has been demonstrated to impair dopaminergic (DAergic) neurons and highly correlate with the etiology of Parkinson's disease (PD). WNT/β-CATENIN signaling is known for the specification and neurogenesis of midbrain DAergic neurons and implicated as a therapeutic target in treating many diseases, such as cancer and degenerative diseases. LGK974, a WNT pathway inhibitor, is currently under clinical trial for patients with malignancies. Since the exact role of WNT/β-CATENIN signaling in mediating PD is undetermined, LGK974 was used to examine its effect on the PQ-induced cell model of PD. LGK974 attenuated PQ-induced apoptosis and released mitochondrial pro-poptotic molecules in human neuroblastoma SH-SY5Y cell. PQ increased the levels of β-CATENIN, non-phosphorylated (Ser33/37/Thr41) β-CATENIN, and phosphorylated glycogen synthase kinase (GSK)-3α/β. PQ also increased the nuclear translocation of β-CATENIN, which can be attenuated by LKG974. Furthermore, LGK974 attenuated the PQ-induced release of mitochondrial proapoptotic factors and WNT agonist 1-induced cell death. Taken together, we have shown for the first time that LGK974 mediated through the WNT/β-CATENIN pathway to prevent PQ-induced cell death.

Gastrodia elata alleviates mutant huntingtin aggregation through mitochondrial function and biogenesis mediation

BACKGROUND

According to the Compendium of Materia Medica, Gastrodia elata (GE) Blume is a top-grade herbal medicine frequently used to treat dizziness, headaches, tetanus, and epilepsy, suggesting that it affects neurological functions. Although studies have supported its effects in preventing diverse neurodegenerations such as Huntington's disease (HD), its mechanisms require further investigation.

PURPOSE

To investigate the ability of the molecular mechanism of GE to prevent mutant huntingtin (mHTT) protein aggregation by focusing on mitochondrial function and biogenesis, which have been proposed as the therapeutic targets of HD.

STUDY DESIGN/METHODS

mHtt overexpression in pheochromocytoma (PC12) cells was used as an in vitro cell model of HD. A retardation assay was applied to measure protein aggregation during Htt expression. Cotransfection with transcriptional genes was used to test their relationships with HTT aggregates by monitoring with a confocal laser scanning microscope. Western blot analysis was used to estimate protein expression under different drug treatments or when cotransfected with other related genes.

RESULTS

Mutant, abnormal Htt overexpression resulted in significant protein aggregation in PC12 cells. GE dose-dependently attenuated mHTT aggregates and increased cyclic-AMP response element-binding protein (CREB) phosphorylation. Adenosine A_2A-R receptor (A_2A-R) antagonist counteracted these phenomena. CREB overexpression significantly attenuated mHTT aggregation. GE increased the promoter activity and expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α). Furthermore, wild-type PGC-1α but not mutant PGC-1α overexpression attenuated mHTT aggregates.

CONCLUSION

GE attenuated mHtt aggregation by mediating mitochondrial function and biogenesis through the A_2A-R/PKA/CREB/PGC-1α-dependent pathway.

Meroterpenoids and Chalcone-Lignoids from the Roots of Mimosa diplotricha

Six new meroterpenoids, diplomeroterpenoids A-F (1-6), two new chalcone-lignoids, diplochalcolins A and B (7, 8), and 13 known compounds were isolated from the root extract of Mimosa diplotricha. Diplomeroterpenoids A-F consist of a 4H-chromen-4-one and a diterpenoid unit, and their absolute configurations were determined by X-ray crystallographic analysis. Compounds 1-3 and 5 showed potent inhibitory activity on protein farnesyl transferase, with IC₅₀ values from 5.0 to 8.5 μM. Compound 1 showed antiproliferative activity against human hepatoblastoma HepG2 cells with a GI₅₀ value of approximately 8.6 μM.

Synthesis and evaluation of 3-ylideneoxindole acetamides as potent anticancer agents

Indirubin, an active component in the traditional Chinese medicine formula Danggui Longhui Wan, shows promising anticancer effects. Meisoindigo is an analog derived from indirubin, which is less toxic and appears to be even more potent against cancer. In considering meisoindigo as a structural template for the development of new drugs, we designed and synthesized a series of 3-ylideneoxindole acetamides as novel anticancer agents. The acetamides were then evaluated for in vitro and in vivo anticancer activities. The 3-ylideneoxindole acetamides were found to have better anticancer activity than was indirubin-3'-oxime in several cancer cell lines and also displayed a spectrum of activity similar to that of the drug candidate roscovitine, a CDK inhibitor. Among the 3-ylideneoxindole acetamides, compound 10 showed particularly good efficacy. Cell cycle analysis further revealed that compound 10 arrested cells in the G1 phase and caused an increase in the sub-G1 population, indicating that the apoptosis pathway had been induced. In addition, exposure of cells to compound 10 led to the upregulation of the cell-cycle regulator cyclin D1, which was sustained at a high level. In contrast, the same compound induced a short-term elevation in the level of cyclin E, which was followed by a rapid decrease and the attenuation of Rb phosphorylation. Furthermore, a docking model suggests that compound 10 binds to the active site of CDK4. In testing the therapeutic potency of compound 10 on CT26-xenografted BALB/c mice, a significant reduction in tumor size comparable to that of cisplatin was found when administrated via the i.p. route. The mice presented no loss of body weight, indicating that this compound possesses low toxicity. In the future, we are planning in vivo investigations of these new active anticancer agents to better elucidate active mechanisms at the cellular level and thus benefit the development of anticancer therapies.

Isolation and cytotoxic effect of anthraquinones from Morinda umbellata

Four new anthraquinones, 1,6-dihydroxy-2-methoxymethylanthraquinone (1), 6-hydroxy-7-methoxy-2-methoxymethylanthraquinone (3), 3,6-dihydroxy-7-methoxy-2-methylanthraquinone (4), and 6-hydroxy-2-methoxymethylanthraquinone (8), together with 12 known anthraquinones and 6 other known compounds, were isolated from the EtOAc extract of Morinda umbellata. Among the isolated compounds, 1, rubiadin (14), and, 3-hydroxy-2-hydroxymethylanthraquinone (16) exhibited significant cytotoxicities against HepG2 cells, with GI50 values of 4.4, 3.6, and 4.8 µM, respectively.

Ajugalide-B (ATMA) is an anoikis-inducing agent from Ajuga taiwanensis with antiproliferative activity against tumor cells in vitro

Ajuga taiwanensis is widely used for the treatment of hepatitis and hepatoma in Taiwanese folk medicine. However, its bioactive components and mechanism of action are unclear. Herein, ajugalide-B (ATMA), a neoclerodane diterpenoid isolated from Ajuga taiwanensis, is reported to exhibit high anti-proliferative activity against tumor cell lines from various tissues. These results demonstrate that ATMA disrupts the focal adhesion complex by decreasing phosphorylation of paxillin and focal adhesion kinase (FAK). As a result, anoikis, a specific type of apoptosis caused by detachment of cells, is triggered by activation of caspase-8 in A549 cells. Furthermore, ATMA also blocks anchorage-independent growth and cell migration and, therefore, ATMA may serve as a lead compound for the developing of anti-cancer therapeuties with anoikis-inducing properties.

Cytotoxic phenylpropanoids and a new triterpene, turformosinic acid, from Turpinia formosana Nakai

One new phenylpropanoid, turformosin A (1), and one new triterpene, turformosinic acid (2), together with 16 known compounds, were isolated from the stems of Turpinia formosana Nakai. All structures were elucidated on the basis of spectroscopic analysis, including 1D- and 2D-NMR techniques and MS analysis. Selected isolated compounds were evaluated for in vitro cytotoxicity against four human cancer cell lines and antioxidant scavenging effects on DPPH. (−)-(7′S,8′S)-threo-carolignan X (3) exhibited cytotoxicity against Hep2, WiDr, Daoy, and MCF-7 cell lines with ED₅₀ values of 3.60, 4.45, 6.07, and 13.7 μg/mL, respectively. Turformosin A (1), (−)-(7′S,8′S)-threo-carolignan X (3), methoxyhydroquinone-4-β-D-glucopyranoside (5), and methoxy-hydroquinone-1-β-D-glucopyranoside (6), exhibited similar anti-oxidative activity. Hep2 cells treated with 10 μg/mL of 3 showed elevation of sub-G1 population (from 20% at 8 h to 60% at 48 h), and activation of caspase-9/caspase-3/PARP cascade. Compound 3 induced intrinsic apoptotic pathway in Hep2 cells with dose and time dependence (10 μg/mL for 8 h).

5-deoxyflavones with cytotoxic activity from Mimosa diplotricha

Bioassay-guided isolation of Mimosa diplotricha led to the isolation of four new 5-deoxyflavones, diplotrins A-C (1-3) and diplotasin (4), together with 12 known flavonoids, flavonolignans, and triterpenoids. On the basis of spectroscopic evidence, compounds 1-4 were characterized as 2',5'-dihydroxy-3,7,8,4'-tetramethoxyflavone (1), 3'-hydroxy-3,7,8,4'-tetramethoxyflavone (2), 2'-hydroxy-7,4',5'-trimethoxyflavone (3), and 4-hydroxy-3,10,11-trimethoxyisochromeno-[4,3-b]-chromen-7(5H)-one (4). The cytotoxic effects of these isolated compounds were evaluated against the A549, AGS, HT-29, and PC3 human cancer cell lines. Compounds 2 and 5″-methoxyhydnocarpin-D (5) showed the most potent antiproliferative activity.

Cytotoxic Hexacyclic Triterpene Acids from Euscaphis japonica

Six hexacyclic triterpene acids (1-6), named euscaphic acids A-F, and eight known triterpene acid compounds (7-14) were isolated from an ethanolic extract of twigs of Euscaphis japonica. Compounds 8 and 10 were isolated for the first time from a natural source. Triterpenes 1-6 possess hexacyclic skeletons with a 13α,27-cyclopropane ring. Structural elucidation of compounds 1-6 was established by spectroscopic methods, especially 2D NMR techniques ((1)H-(1)H COSY, HMQC, HMBC, and NOESY). Compounds 3, 4, and 14 showed significant cytotoxicity against different cancer cell lines [IC50 = 2.54 (NCI-H460), 3.61 (MCF-7), and 3.27 μM (CEM) for 3, 4, and 14, respectively].

A physical concept of soil-water equilibria for nonionic organic compounds

Soil-water equilibrium data suggest that the transfer of nonionic chemicals from water to soil may be described in terms of a hypothesis of solute partitioning in the soil organic matter. This concept allows estimation of soil-water distribution coefficients either from solvent-water partition coefficients or aqueous solubilities.

Cytotoxic polyisoprenyl benzophenonoids from Garcinia subelliptica

Six new polyisoprenyl benzophenonoids, (+/-)-garcinialiptone A (1, 2), garcinialiptone B (3), (-)-cycloxanthochymol (4), garcinialiptone C (5), and garcinialiptone D (6), along with three known compounds, xanthochymol (7), isoxanthochymol (8), and cycloxanthochymol (9), were isolated from the fruits of Garcinia subelliptica. The structures of 1-6 were elucidated by spectroscopic analysis. Biological evaluation showed that all compounds 1-9 exhibited cytotoxic activity against a small panel of human tumor cell lines (A549, DU145, KB, vincristine-resistant KB).

Structure-based discovery of triphenylmethane derivatives as inhibitors of hepatitis C virus helicase

Hepatitis C virus nonstructural protein 3 (HCV NS3) helicase is believed to be essential for viral replication and has become an attractive target for the development of antiviral drugs. A fluorescence resonant energy transfer helicase assay was established for fast screening of putative inhibitors selected from virtual screening using the program DOCK. Soluble blue HT (1) was first identified as a novel HCV helicase inhibitor. Crystal structure of the NS3 helicase in complex with soluble blue HT shows that the inhibitor bears a significantly higher binding affinity mainly through a 4-sulfonatophenylaminophenyl group, and this is consistent with the activity assay. Subsequently, fragment-based searches were utilized to identify triphenylmethane derivatives for more potent inhibitors. Lead optimization resulted in a 3-bromo-4-hydroxyl substituted derivative 12 with an EC(50) value of 2.72 microM to Ava.5/Huh-7 cells and a lower cytotoxicity to parental Huh-7 cells (CC(50) = 10.5 microM), and it indeed suppressed HCV replication in the HCV replicon cells. Therefore, these inhibitors with structural novelty may serve as a useful scaffold for the discovery of new HCV NS3 helicase inhibitors.

Association of Japanese encephalitis virus NS3 protein with microtubules and tumour susceptibility gene 101 (TSG101) protein

Previously reported findings by our group showed that non-structural protein 3 (NS3) of Japanese encephalitis virus (JEV) was localized mainly in the JEV-induced convoluted membrane (CM), which has been proposed to originate from rough endoplasmic reticulum (rER), Golgi apparatus or the trans-Golgi network (TGN), and serves as a reservoir for viral proteins during virus assembly. Earlier findings indicated that NS3 of Kunjin virus interacts with microtubules. In addition, one of the Golgi-associated proteins, tumour susceptibility protein 101 (TSG101), associates with microtubules and is required for budding of retroviral particles. To clarify the association of NS3 with microtubules or with TSG101 during JEV assembly, we applied immunofluorescence, co-immunoprecipitation and immunoelectron microscopic methods. Virus infection, as well as transfection with an NS2B-NS3 expression plasmid, induced microtubule rearrangement. When cells were treated with colchicine, which interferes with microtubule polymerization, NS3 still associated with tubulin and TSG101. Furthermore, tubulin and TSG101 were co-localized with NS3 in the CM by immunogold labelling. Our observations indicate that microtubules and TSG101 associate with NS3, which is incorporated into the JEV-induced structure during JEV replication.

Tracking the assembly pathway of human immunodeficiency virus type 1 Gag deletion mutants by immunogold labeling

The Pr55gag gene product of human immunodeficiency virus type 1 (HIV-1) is sufficient to direct the formation of retrovirus-like particles (RVLPs). Recent biochemical evidence has indicated the presence of Gag intermediates in the cytoplasm; however, the Gag assembly process into RVLPs remains incompletely defined. The authors present here the subcellular localization of Gag mutant proteins in BSC40 and Jurkat cells by immunoelectron microscopy (IEM). The full Gag/Pol and Gag precursors, a C-terminal deletion mutant lacking a portion of nucleocapsid (NC), and all p6Gag gave rise to similar levels of RVLPs at the cell surface. A C-terminal deletion of all NC and p6Gag abrogated particle formation, whereas p24 was found in patches at the cell surface. Deletion of matrix (MA) sequences from Gag resulted in intracellular particles, and myristylation was not required for particle formation in the context of the MA deletion. Matrix expression was enhanced with Gag/Pol or Env coexpression as determined by semiquantitative IEM. p24 protein was targeted at vacuolar and mitochondrial membranes, but not at Golgi cisternae. In addition, aggregations of Gag intermediates and RVLPs in the cytoplasm, rough endoplasmic reticulum, cisternae, and mitochondria were noted. These results provide defined in situ evidence that HIV-1 particle assembly occurs in the cytosol in addition to budding at most intracellular membranes.

Water solubility enhancements of pyrene by single and mixed surfactant solutions

Water solubility enhancements of pyrene by both single-surfactant and mixed-surfactant solutions were compared and evaluated. The solubility of pyrene in water was greatly enhanced by each of Triton X-100 (TX100), Triton X-405 (TX405), Brij 35 and SDS, in which the water solubility enhancements increased with increasing surfactant concentrations. The extent of solubility enhancements at surfactant concentrations below the CMC is the order of TX100 > Brij 35 > TX405 > SDS; the sequence at surfactant concentrations above the CMC is TX100 > Brij 35 > SDS > TX405. Pyrene was solubilized synergistically by anionic-nonionic mixed surfactant solutions, especially at low surfactant concentrations. The synergistic power of the mixed surfactants is SDS-TX405 > SDS-Brij 35 > SDS-TX100. The synergism as noted is attributed to increasing Kmc is and/or decreasing the CMC of the mixed surfactant solution. For SDS-TX405 and SDS-Brij 35 mixed surfactant solutions, an increase in Kmc is coupled with a decrease in the CMC; for SDS-TX100, only a decreased in the CMC value is noted. Mixed-surfactant solutions may improve the performance of the surfactant-enhanced remediation (SER) of soils by increasing the bioavailability and biodegradation of non-aqueous-phase organic pollutants and reducing the level of surfactant pollution and remediation expenses.

A partition-limited model for the plant uptake of organic contaminants from soil and water

In dealing with the passive transport of organic contaminants from soils to plants (including crops), a partition-limited model is proposed in which (i) the maximum (equilibrium) concentration of a contaminant in any location in the plant is determined by partition equilibrium with its concentration in the soil interstitial water, which in turn is determined essentially by the concentration in the soil organic matter (SOM) and (ii) the extent of approach to partition equilibrium, as measured by the ratio of the contaminant concentrations in plantwater and soil interstitial water, alphapt (< or = 1), depends on the transport rate of the contaminant in soil water into the plant and the volume of soil water solution that is required for the plant contaminant level to reach equilibrium with the external soil-water phase. Through reasonable estimates of plant organic-water compositions and of contaminant partition coefficients with various plant components, the model accounts for calculated values of alphapt in several published crop-contamination studies, including near-equilibrium values (i.e., alphapt approximately equals 1) for relatively water-soluble contaminants and lower values for much less soluble contaminants; the differences are attributed to the much higher partition coefficients of the less soluble compounds between plant lipids and plant water, which necessitates much larger volumes of the plant water transport for achieving the equilibrium capacities. The model analysis indicates that for plants with high water contents the plant-water phase acts as the major reservoir for highly water-soluble contaminants. By contrast, the lipid in a plant, even at small amounts, is usually the major reservoir for highly water-insoluble contaminants.

Influence of a Nonionic Surfactant (Triton X-100) on Contaminant Distribution between Water and Several Soil Solids

The influence of a nonionic surfactant (Triton X-100) on the contaminant distribution coefficients in solid-water mixtures was determined for a number of relatively nonpolar compounds (contaminants) on several natural solids. The studied compounds consisted of BTEX (benzene, toluene, ethylbenzene, and p-xylene) and chlorinated pesticides (lindane, alpha-BHC, and heptachlor epoxide), which span several orders of magnitude in water solubility (S(w)); the solid samples comprised a bentonite, a peat, and two other soils, which cover a wide range of solid organic matter (SOM) content. The applied surfactant concentrations (X) ranged from below the (nominal) CMC to 2-3 times the CMC. For relatively water-soluble BTEX compounds, the distribution coefficients with surfactant (K(d)*) all exceeded those without surfactant (K(d)); the K(d)*/K(d) ratios increased with increasing S(w) from p-xylene to benzene on each solid at a given X, with increasing X for each compound on a solid, and with decreasing solid SOM content for each compound over the range of X studied. For the less-soluble pesticides, the K(d)*/K(d) ratios exhibited a large increase with X for bentonite, a marginal change (increase or decrease) for a soil of 2.4% SOM, and a moderate-to-large decrease for two soils of 14.8% and 86.4% SOM. These unique observations were rationalized in terms of the properties of the compound, the amount of surfactant sorbed on the solid, the enhanced solubilization of the compound by surfactant in water, and the relative effects of the surfactant when adsorbed on minerals and when partitioned into SOM. Copyright 2000 Academic Press.

Localizations of NS3 and E proteins in mouse brain infected with mutant strain of Japanese encephalitis virus

Infection with a mutant Japanese encephalitis virus (JEV) strain RP-2ms showed reduced neurovirulence than wild type or RP-9 strains after inoculation in BALB/c mice. However, higher intracellular viral titer was detected in Rp-2ms infected cultured cells. Localizations of non-structural 3 (NS3) and envelope (E) proteins were demonstrated by immunocytochemistry. NS3 protein was primarily found in the pyramidal neurons in cerebrum, in the molecular and granular layers of cerebellum. Neither E nor NS3 protein was detected in Purkinje cells of the cerebellum. Immunoelectron microscopic observations showed that E and NS3 proteins were positive in JEV-induced membranous systems, mainly hypertrophic rough endoplasmic reticulum (rER) and membrane vesicle structure (MVS) but not smooth membrane structure. Virus particles were seen in the Golgi apparatus, rER, nuclear envelope, MVS and cytoplasmic vacuoles. Different mechanisms of intracellular trapping in vivo provide a possible basis for attenuation of RP-2ms strains of JEV.

Ultrastructure and localization of E proteins in cultured neuron cells infected with Japanese encephalitis virus

A unique structure and in situ localization of E proteins were demonstrated in cultured neurons infected with neurovirulent and aneurovirulent strains of local Japanese encephalitis virus (JEV). Dilated rough endoplasmic reticulum (rER) containing smooth membrane structures (SMS) was continuous with the outer membrane of the nuclear envelope. These membranes were found to be connected to unique dense bodies, membrane vesicle structures (MVS). The de novo formation of SMS, annulate lamellae, and the appearance of MVS indicated proliferation of the membranous system in response to JEV infection. E proteins were possibly assembled in the virions in the nuclear envelope or rER or on the plasma membrane. The interconnections between MVS, rER, and the nuclear envelope and immunogold labeling of E proteins on the MVS provided strong evidence that MVS serve as a reservoir of JEV components during virus assembly.

Some physical factors in toxicological assessment tests

Many thousand organic compounds are in common use and new ones introduced daily. With many of these materials, little is known about their toxic hazard. For years scientists have been investigating the relation of structure and properties to biological activity. Among the factors relating to toxicity are bioaccumulation and persistence in the organism. In this study, the relation of partition coefficient and solubility to bioaccumulation of some organochlorine compounds was investigated as was also the reactivity of several organophosphates. The work adds confirmation to the relation of molecular parameters to penetration, accumulation, and persistence in toxic action.