Tricin-enriched Zizania latifolia ameliorates non-alcoholic fatty liver disease through AMPK-dependent pathways

This study aimed to identify and elucidate the mechanism underlying the protective effect of tricin-enriched Zizania latifolia (Z. latifolia) extract (ETZL) against free fatty acid (FFA)-induced lipid accumulation in vitro and non-alcoholic fatty liver disease (NAFLD) induced by a high-fat diet and fructose diet (HFD/F) in vivo. ETZL treatment significantly lowered body weight gain and decreased adipose tissue, lipid, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) levels in HFD/F-fed mice. ETZL acted on phosphorylated acetyl-CoA carboxylase (ACC) and anti-peroxisome proliferator-activated receptor α (PPARα) by activating the adenosine monophosphate-activated protein kinase (AMPK) pathway and inhibiting sterol regulatory element-binding proteins-1 (SREBP)/fatty acid synthase (FAS) signaling to inhibit de novo adipogenesis and increase fatty acid oxidation. In addition, treatment with ETZL increased nuclear factor erythroid-2-related factor 2 (Nrf2) levels to activate the antioxidant pathway. FFA-induced oxidative stress and fatty acid accumulation in HepG2 cells confirmed the improvement in fat accumulation through the AMPK and Nrf2 pathway activities of ETZL. These results suggest that ETZL ameliorates NAFLD by regulating lipid metabolism and defending against oxidative stress via AMPK-dependent pathways.

Curcubinoyl flavonoids from wild ginseng adventitious root cultures

Wild ginseng (Panax ginseng) adventitious root cultures were prepared by elicitation using methyl jasmonate and investigated further to find new secondary metabolites. Chromatographic fractionation of wild ginseng adventitious root cultures led to the isolation of eleven compounds. The chemical structures of isolated compounds were identified as four known flavanone derivatives (1–4), one new curcubinoyl derivative, jasmogin A (5) and six new curcubinoyl-flavanone conjugates, jasmoflagins A-F (6–11) by extensive spectroscopic analysis. Newly isolated curcubinoyl derivatives showed inhibitory activity against lipopolysaccharide-stimulated nitric oxide production in RAW 264.7 macrophages. Therefore, our present study suggested that elicitor stimulated plant cell cultures might contribute to the production of new metabolites.

Anomalous Rabi Oscillations in Multilevel Quantum Systems

We show that the excitation probability of a state within a manifold of levels undergoes Rabi oscillations with the frequency determined by the energy difference between the states and not by the pulse area, for sufficiently strong pulses. The population and coherence remains in the two-level subsystem formed by the initial and target state even at Rabi frequencies exceeding the energy difference. The observed dynamics can be useful in nonlinear spectroscopy and quantum state preparation.

Evaluation of estrogenic potential by herbal formula, HPC 03 for in vitro and in vivo

HPC 03 is herbal formula that consists of extracts from Angelica gigas, Cnidium officinale Makino and Cinnamomum cassia Presl. The present study evaluated the estrogenic potential of HPC 03 by using in vitro and in vivo models. The regulatory mechanisms of HPC 03 in estrogen-dependent MCF-7 cells were assessed. HPC 03 induced the proliferation of estrogen receptor-positive MCF-7 cells, and the proliferation was blocked by the addition of the estrogen antagonist tamoxifen. The estrogen receptor_α/β luciferase activities were significantly increased by HPC 03 treatment, which also increased the mRNA expression of the estrogen-responsive genes Psen2, Pgr and Ctsd Also, we evaluated the ameliorative effects of HPC 03 on menopausal symptoms in ovariectomized rats. HPC 03 treatment in OVX rats significantly affected the uterine weight, increased the expression of estrogen-responsive genes Pgr and Psen2 in uterus, increased bone mineral density loss in the femur and inhibited body weight increase. Serum E2, collagen type 1 and osteocalcin were significantly increased, while serum LH, FSH and ALP were decreased compared with OVX rats. HPC 03 may be a promising candidate for the treatment of menopause, but further research is necessary to determine whether the observed effects also occur in humans.

Fraxin Prevents Chemically Induced Hepatotoxicity by Reducing Oxidative Stress

Fraxin isolated from Acer tegmentosum is reported to exert potent anti-oxidative stress action. However, pharmacological activities of fraxin remain to be elucidated. This study investigated the potential hepatoprotective effects of fraxin and the underlying signaling mechanism involved. Treatment with fraxin significantly lowered the serum levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in a CCl₄-induced hepatotoxicity rat model. In the fraxin-treated group, glutathione (GSH) significantly increased, while the malondialdehyde (MDA) in the liver significantly decreased. Fraxin also showed radical-scavenging activity. Furthermore, it significantly reduced the t-BHP-induced cytotoxicity and production of reactive oxygen species (ROS) in Hep G2. Fraxin protected Hep G2 cells through Nrf2 pathway-dependent HO-1 expression. The results of this study indicate that fraxin shows potent hepatoprotective effects in vitro and in vivo, presumably through direct antioxidant activity and the Nrf2-mediated antioxidant enzyme system.

Potential of the Cnidium monnieri fruits as an immune enhancer in Escherichia coli infection model

OBJECTIVES

The Cnidium monnieri fruits (CMF) were studied how they act on immune system as a novel immunostimulator against the infectious disease.

METHODS

Macrophages were treated with CMF, and nitric oxide (NO) and tumour necrosis factor-α (TNF-α) were measured, and phagocytosis of macrophages was detected using FITC-labelled Escherichia coli. The protective effect of CMF against E. coli infection in mice was examined. The survival rate was monitored daily for up to 5 days. And then the viable bacteria count of serum and the immunological mediator (NO, TNF-α, interleukin (IL)-12 and IL-6) of serum, splenocyte and peritoneal macrophages were analysed.

KEY FINDINGS

The CMF significantly enhanced the concentrations of NO and TNF-α and the phagocytosis activity in macrophages. The oral administration of CMF for five consecutive days before infection prolonged the survival rate. Treatment with CMF significantly stimulated the phagocytosis of peritoneal macrophages and induced the immunological mediator of serum, splenocyte and peritoneal macrophages against the E. coli infection.

CONCLUSIONS

The host-protective effects of CMF might be archived by improving immune response, and CMF could act to prevent pathogenic microbial infections with immunomodulation.

Nonclinical Safety Assessment of Morus alba L. Fruits: Study of 90-D Toxicity in Sprague Dawley Rats and Genotoxicity in Salmonella

Morus alba L. is a traditional herb with a long history of consumption, both as an edible fruit and as medicine. However, its safety evaluation has not yet been established. The objective of this study was to evaluate subchronic oral toxicity and genotoxicity of M. alba L. fruits (MFE). The subchronic toxicity after daily oral administration of MFE at 0, 40, 200, and 1000 mg/kg for 90 d was examined in Sprague Dawley (SD) rats. MFE administration did not lead to death, adverse effects, change in food and water consumption, and body weight gain. Significant toxic effects were not found within the parameters of organ weight, biochemical values, and hematological and urine analysis between the control and the MFE group. The genotoxicity of MFE was assayed by Ames test in Salmonella typhimurium strains TA98, TA102, and TA1535. No genotoxicity was found in all the tested strains. Thus in this study, a no-observed-adverse-effect level for MFE in 90 d repeated oral toxicity study in rats was determined to be greater than 1000 mg/kg regardless of gender. The results also suggested that MFE does not have a genotoxicity potential.

Protective activity of kudzu (Pueraria thunbergiana) vine on chemically-induced hepatotoxicity: in vitro and in vivo studies

Background

Kudzu (Pueraria thunbergiana) root has long been used in Traditional Chinese Medicine. However, the vine of the kudzu plant has been considered waste material. This study aimed to investigate the hepatoprotective properties of the kudzu vine.

Methods

We created 0 %, 30 %, 70 %, and 95 % ethanolic kudzu vine extracts. The isoflavone contents of kudzu vine extract were quantified by high-performance liquid chromatography. Tertiary-butylhydroperoxide (t-BHP) was added to human liver-derived HepG2 cells, and the production of reactive oxygen species was measured in the presence and absence of kudzu vine extract. Antioxidant activity was evaluated in all kudzu vine extracts using a hydroxyradical scavenging assay. Thirty-five male Sprague–Dawley rats were divided into seven groups (n = 5); two groups were not given any extract or drug, one group was treated with 50 mg/kg silymarin orally for 5 days, and the remaining four groups were respectively treated with 100 mg/kg of 0 %, 30 %, 70 %, or 95 % ethanolic extract of kudzu vine orally once daily for 5 days. On day 5 the treatment groups and one untreated group were fed 0.75 ml/kg carbon tetrachloride (CCl₄) to induce liver damage. Blood and liver tissue samples were collected 24 h after CCl₄ administration for measurement of plasma alanine aminotransferase and aspartate aminotransferase, and concentration of malondialdehyde and glutathione in liver tissue.

Results

Puerarin was the most abundant isoflavone in kudzu vine extract. Kudzu vine extract significantly reduced the cytotoxicity and production of reactive oxygen species induced by t-BHP in a dose-dependent manner. Treatment with 0 % and 30 % ethanolic extracts of kudzu vine significantly lowered the plasma levels of alanine aminotransferase and aspartate aminotransferase in a CCl₄-induced hepatotoxicity rat model (P < 0.05). Glutathione was significantly elevated in the 30 % ethanolic extract-treated group (P < 0.05), while the malondialdehyde level in liver tissue was significantly decreased in the 0 % and 30 % ethanolic extract-treated groups (P < 0.05).

Conclusions

The kudzu vine is potentially highly beneficial in treating liver damage, as it scavenges reactive free radicals and boosts the endogenous antioxidant system.

External dacryocystorhinostomy in consultants and fellows - a comparison of the causes of failure

PURPOSE

Failure of primary dacryocystorhinostomy (DCR) often requires revision surgery to inspect the cause of failure and re-establish anatomic patency. This study aims to specifcally compare the anatomical causes of failure noted during revision DCR of primary external DCR (EX-DCR) and compare the difference between consultants and fellows.

METHODS

A retrospective review of 37 patients who underwent revision of a primary external approach DCR over a 7-year-period in a University Hospital. All primary surgery was performed by either a consultant surgeon or senior oculoplastic fellow. Details of the initial pathology prior to primary DCR and grade of operating surgeon were collected along with perioperative surgical findings. The cause of failure of the initial surgery was classified according to perioperative findings. Failure was classified as either inappropriately sized/located ostium or fibrous/membranous soft tissue obstruction of the newly created ostium.

RESULTS

The cause of failure of the initial surgery was soft tissue obstruction in 43.3% and an inappropriately sized/located ostium in 56.7%. In those patients whose primary surgery was performed by a consultant, 73.3% were found to have a soft tissue obstruction and 26.7% were found to have an inappropriately sized/ located ostium. In contrast, if initial surgery was performed by a fellow, 22.7% were found to have a soft tissue obstruction and 77.3% an inappropriately sized/ located ostium (p =0.002).

CONCLUSIONS

Where the primary surgeon has been a trainee there is a trend toward inadequately sized or located ostium being the most likely causative factor in failure of primary EX-DCR.  Hippokratia 2015; 19 (3): 216-218.

Pyrrole alkaloids from the fruits of Morus alba

Phytochemical investigation of the fruits of Morus alba afforded seventeen pyrrole alkaloids including five new compounds. The structures of five new pyrrole alkaloids, named morroles B-F (4, 5, 7, 16 and 17), were determined on the basis of spectroscopic interpretations. 4-[Formyl-5-(hydroxymethyl)-1H-pyrrol-1-yl]butanoate (2) was synthesized by chemical reaction but first isolated from nature. Among isolated compounds, compounds 6 and 14 significantly inhibited pancreatic lipase activity.

The Effect of Selective Estrogen Receptor Modulators (SERMs) on the Tamoxifen Resistant Breast Cancer Cells

Selective estrogen receptor modulators (SERMs) are synthetic molecules which bind to estrogen receptors (ER) and can modulate its transcriptional capabilities in different ways in diverse estrogen target tissues. Tamoxifen, the prototypical SERM, is extensively used for targeted therapy of ER positive breast cancers. Unfortunately, the use of tamoxifen is associated with acquired resistance and some undesirable side effects. This study investigated the availability of the conventional SERMs on the TAM-resistance breast cancer cells. SERMs showed more effectiveness in MCF-7 cells than tamoxifen resistant cells, except toremifene and ospemifene. Especially, toremifene was more efficacious in tamoxifen resistant cells than MCF-7. Ospemifene had similar cytotoxic activity on the two types of breast cancers. The other SERMs used in this experiment didn’t inhibit efficiently the proliferation of tamoxifen resistant cells. These results support the possibility to usage of toremifene on tamoxifen resistant cancer. The effectiveness by toremifene on tamoxifen resistant cells might be different pathways from the apoptosis and the autophagy. Further study should be needed to elucidate the underlying mechanism of effect of toremifene on tamoxifen resistant cancer.

A new phenolic glycoside from Cnidium monnieri fruits

A new phenolic glycoside, methylpicraquassioside B (6), together with nine known glycosides, cnidioside A (1), cnidioside B (2), picraquassioside A (3), methylpicraquassioside A (4), picraquassioside B (5), xanthotoxol-8-β-glucoside (7), 5-methoxy-xanthotoxol-8-β-glucoside (8), 8-methoxy-xanthotoxol-5-β-glucoside (9) and marmesinin (10) were isolated from n-BuOH-soluble fraction of Cnidium monnieri fruits. All the isolated compounds, however, exerted little immunomodulatory effect in RAW 264.7 cells.

Macrophage activating activity of pyrrole alkaloids from Morus alba fruits

ETHNOPHARMACOLOGICAL RELEVANCE

The fruits of Morus alba have been traditionally used as a tonic to enhance immune responses.

MATERIALS AND METHODS

The macrophage activating constituents of Morus alba fruits were purified using various column chromatography techniques. The structures of isolated compounds were determined on the basis of spectroscopic data interpretation such as 1D and 2D NMR analysis. The macrophage activating activities of isolated compounds were evaluated by measuring the production of nitric oxide, TNF-α and IL-12 in RAW 264.7 cells. The phagocytic activity was also evaluated.

RESULTS

Five pyrrole alkaloids, 5-(hydroxymethyl)-1H-pyrrole-2-carboxaldehyde (1), 2-formyl-1H-pyrrole-1-butanoic acid (2), 2-formyl-5-(hydroxymethyl)-1H-pyrrole-1-butanoic acid (3), 2-formyl-5-(methoxymethyl)-1H-pyrrole-1-butanoic acid (4) and Morrole A (5) were isolated from the fruits of Morus alba. Morrole A (5) is first reported in nature and other pyrrole alkaloids (1-4) are first reported from Morus species. Among the isolated compounds, compounds 3 and 4 significantly activated macrophage activity by the enhancement of nitric oxide, TNF-α and IL-12 production, and the stimulation of phagocytic activity in RAW 264.7 cells.

CONCLUSION

Pyrrole alkaloids, including a new compound, were isolated from Morus alba fruits. These compounds activated macrophage activity in RAW 264.7 cells.

Simultaneous determination of salbutamol, ractopamine, and clenbuterol in animal feeds by SPE and LC-MS

A liquid chromatography-mass spectrometry (LC-MS) method for the simultaneous determination of salbutamol, ractopamine, and clenbuterol in commercial feeds was developed. Samples were extracted with phosphoric acid-methanol solution, and further clean-up was achieved with a C18 cation exchange mixed mode cartridge. Separation of analytes was developed on a C18 column with 0.01 M aqueous ammonium formate solution (pH 3.8)-acetonitrile by gradient program, and characterized by LC-MS on a quadrupole detector, in electrospray positive ion mode. This method provides average recoveries for salbutamol, ractopamine, and clenbuterol of 83-110% and coefficients of variation of 1.5-11% in feeds spiked in the range of 0.5-500 mg/kg. The limits of detection and quantification in feeds were 0.01 mg/kg and 0.05 mg/kg, respectively. Such limits are well below the dose of 2-25 mg/kg feed proposed as effective.

Effects of lentinan on broiler splenocyte proliferation, interleukin-2 production, and signal transduction

Lentinan (LEN) is an intensively studied beta-glucan that has been shown to have immunostimulating and antitumor functions. However, it currently is not used in veterinary practice and animal production. This study was conducted to investigate the impacts of LEN on broiler splenocyte proliferation, interleukin-2 (IL-2) production, and to explore its effects on receptor signal transduction by determining signaling molecules, including nitric oxide (NO), cytosolic-free Ca2+, cytosolic cyclic adenosine monophosphate (cAMP), and cyclic guanosine monophosphate (cGMP). The results showed that compared to the control all three measured doses, including 40, 80, and 160 microg/mL LEN, increased splenocyte proliferation and IL-2 production (P < 0.05). Lentinan increased splenocyte NO production and cytosolic-free calcium concentration in a dose-dependent manner (P < 0.001). After incubating splenocytes for 20 min, LEN increased intracellular cAMP and cGMP concentrations at a dose of 80 and 160 microg/mL, respectively. However, after incubating the splenocytes for 60 min, LEN had no effect on cytosolic cAMP and cGMP concentration irrespective of the LEN dosage. Those results indicated that LEN had immunostimulatory effects on splenocytes by increasing splenocyte proliferation and IL-2 production and by activating splenocyte receptor signal transduction.

Effects of Chinese herbal polysaccharides on the immunity and growth performance of young broilers

Two trials were conducted to study the effects of two Chinese herbal polysaccharides [achyranthan (ACH), a low-molecular-weight polysaccharide, and astragalan (APS), a high-molecular-weight polysaccaride] on the immunity and growth performance of young broilers. Trial 1 was a 28-d growth assay, in which 7-d-old broilers (n = 240) were randomly allotted to one of three dietary treatments, with eight replicate pens per treatment and ten chickens per pen. Dietary treatments included a control corn-soy-fishmeal (Treatment 1), a diet with 200 mg/kg APS (Treatment 2), and a diet with 200 mg/kg ACH (Treatment 3). Blood samples were collected by cardiac puncture on Days 7, 14, 21, and 28 for determination of serum parameters, and chickens were killed on Day 28 to measure immune organ indexes. Trial 2 was an in vitro trial to study the effects of different concentrations of polysaccharides on broiler splenocyte functions. In Trial 1, feeding either APS or ACH had no significant effects on growth performance of broilers relative to the control. However, compared to the control, feeding ACH significantly increased microhemagglutination inhibition (HI) antibody titers, bursa of Fabricius index, serum albumin, serum calcium, and nitric oxide (NO) concentrations at Day 28 (P < or = 0.05). In Trial 2, both polysaccharides showed significant immunostimulating effects. They increased NO and interleukin-2 (IL-2) production of splenocytes and enhanced splenocyte proliferation in a dose-dependent manner (P < 0.05). Those results indicate that the immunostimulating effects of APS are not as pronounced as those of ACH. Achyranthan showed immunostimulating effects in both the growth assay and in vitro studies. Therefore, ACH may be a Chinese herbal polysaccharide that has the potential to be used as a feed additive to improve broilers' immunity.

The interaction of Src and RACK1 is enhanced by activation of protein kinase C and tyrosine phosphorylation of RACK1

RACK1 is an intracellular receptor for the serine/ threonine protein kinase C. Previously, we demonstrated that RACK1 also interacts with the Src protein-tyrosine kinase. RACK1, via its association with these protein kinases, may play a key role in signal transduction. To further characterize the Src-RACK1 interaction and to analyze mechanisms by which cross-talk occurs between the two RACK1-linked signaling kinases, we identified sites on Src and RACK1 that mediate their binding, and factors that regulate their interaction. We found that the interaction of Src and RACK1 is mediated, in part, by the SH2 domain of Src and by phosphotyrosines in the sixth WD repeat of RACK1, and is enhanced by serum or platelet-derived growth factor stimulation, protein kinase C activation, and tyrosine phosphorylation of RACK1. To the best of our knowledge, this is the first report of tyrosine phosphorylation of a member of the WD repeat family of proteins. We think that tyrosine phosphorylation of these proteins is an important mechanism of signal transduction in cells.

Functional analyses and identification of two arginine residues essential to the ATP-utilizing activity of the triple gene block protein 1 of bamboo mosaic potexvirus

The TGBp1 of bamboo mosaic potexvirus (BaMV) is encoded by the first overlapping gene of the triple-gene-block (TGB), whose products are thought to play roles in virus movement between plant cells. This protein forms cytoplasmic inclusions associated with virus particles in the BaMV-infected tissues. It has been proposed that the inclusion is one of the active forms of TGBp1. To prove this idea, we purified the TGBp1 inclusions from both the BaMV-infected Chenopodium quinoa and Escherichia coli cells overexpressing this protein to test some of their biochemical activities. We found that the TGBp1 inclusions isolated from the infected plant leaves, but not from E. coli, possess the NTP-binding and NTPase activities. However, they lack the RNA-binding activity possessed by the soluble TGBp1. These results indicate that the TGBp1 proteins in the BaMV-infected tissues assume two different functional forms. Mutational analyses and competition experiments show that the two arginine residues, Arg-16 and Arg-21, essential to RNA binding, are also required for the ATP-utilizing activity of the soluble TGBp1. This indicates that a same-structure motif is required for the two functions of the soluble TGBp1. The location of the two arginine residues outside the seven conserved motifs of the NTP-utilizing superfamily I RNA helicases, to which TGBp1 belongs, suggests that an extra-structure motif, besides the seven conserved ones, is required for the NTP-utilizing activity of the TGBp1 protein of BaMV.

Selective excitation of vibrational states by shaping of light-induced potentials

In this Letter we describe a method for population transfer using intense, ultrafast laser pulses. The selectivity is accomplished by careful shaping of light-induced potentials (LIPs). Creation and control of the LIPs is accomplished by choosing pairs of pulses with proper frequency detunings and time delays. As an example, selective population transfer is demonstrated for a three-state model of the sodium dimer.

Local anaesthetic techniques and pulsatile ocular blood flow

AIM

To compare pulsatile ocular blood flow (POBF) and intraocular pressure (IOP) between eyes of patients receiving either peribulbar (with and without balloon compression) or subconjunctival local anaesthesia (LA).

METHODS

30 eyes of 30 patients undergoing cataract surgery by phacoemulsification were investigated in a study of parallel group design. Ten patients had peribulbar LA and 10 minutes compression with a Honan's balloon (group A). A further 10 patients who received peribulbar LA alone (group B) acted as controls for the effects of balloon compression. Ten other patients were given subconjunctival LA (group C). POBF and IOP were measured using a modified Langham pneumatonometer. Three measurements were made in each eye, the first recording immediately before LA, the second 1 minute after, and the third 10 minutes after LA.

RESULTS

No significant change in POBF or IOP was recorded in eyes receiving subconjunctival LA. In the peribulbar groups (A and B), there was a drop in median POBF of 252 and 138 microl/min respectively 1 minute after LA, which was statistically significant in both groups (p<0. 01). By 10 minutes, POBF tended to return to baseline levels, but remained significantly reduced in group B (p<0.05). In addition, there was a significant (p<0.05) reduction in IOP (mean drop of 4.82 mm Hg) in group A following peribulbar LA with balloon compression.

CONCLUSIONS

POBF was significantly reduced after peribulbar LA but was unchanged after subconjunctival LA. Balloon compression reduced IOP and improved POBF following peribulbar LA. The findings may have clinical implications in patients with compromised ocular circulation or significant glaucomatous optic neuropathy.

Structural and functional properties of a Bacillus subtilis temperature-sensitive sigma(A) factor

Bacillus subtilis DB1005 is a temperature-sensitive (Ts) sigA mutant containing double-amino-acid substitutions (I198A and I202A) on the hydrophobic face of the promoter -10 binding helix of sigma(A) factor. We have analyzed the structural and functional properties of this mutant sigma(A) factor both in vivo and in vitro. Our data revealed that the Ts sigma(A) factor possessed predominantly a multimeric structure which was prone to aggregation at restrictive temperature. The extensive aggregation of the Ts sigma(A) resulted in a very low core-binding activity of the Ts sigma(A) factor and a markedly reduced sigma(A)-RNA polymerase activity in B. subtilis DB1005, suggesting that extensive aggregation of the Ts sigma(A) is the main trigger for the temperature sensitivity of B. subtilis DB1005. Partial proteolysis, tryptophan fluorescence and 1-anilinonaphthalene-8-sulfonate-binding analyses revealed that the hydrophobic face of the promoter -10 binding helix and also the hydrophobic core region of the Ts sigma(A) factor were readily exposed on the protein surface. This hydrophobic exposure provides an important cue for mutual interaction between molecules of the Ts sigma(A) and allows the formation of multimeric Ts sigma(A). Our results also indicate that Ile-198 and Ile-202 on the hydrophobic face of the promoter -10 binding helix are essential to ensure the correct folding and stabilization of the functional structure of sigma(A) factor.

Incidence of anterior intraocular lens precipitates after combined phacotrabeculectomy

PURPOSE

To compare the incidence of anterior intraocular lens (IOL) precipitates on silicone and poly(methyl methacrylate) (PMMA) IOLs after phacotrabeculetomy.

SETTING

District general hospital in the United Kingdom.

METHODS

Ninety-five consecutive eyes of 77 patients who had combined phacotrabeculectomy between April 1992 and October 1996 were retrospectively studied. A slitlamp biomicroscope was used to look for precipitates.

RESULTS

Mean patient age was 75 years (range 51 to 89 years). Preoperatively, mean intraocular pressure (IOP) was 26 mm Hg +/- 5.26 (SD). Thirty plate-haptic silicone IOLs and 65 PMMA IOLs were implanted. Six months postoperatively, median corrected Snellen acuity improved from 6/18 to 6/9. The mean number of antiglaucoma medications dropped from 1.46 preoperatively to 0.29 postoperatively; 73 eyes (76.8%) had an IOP of less than 22 mm Hg with no medication. In 1 surgeon's experience, lens precipitates appeared in 10 of 59 cases (16.9%), with 7 of 14 (50.0%) in the silicone IOL group and 3 of 45 (6.7%) in the PMMA IOL group. The difference was statistically significant (P <.001, chi-square).

CONCLUSION

The incidence of anterior IOL precipitates was significantly higher in patients with a silicone IOL than in those with a PMMA IOL, suggesting that use of silicone IOLs may increase the incidence of postoperative IOL precipitates.

Differential and additive effects of the three conserved isoleucine residues in the promoter -10 binding region on Bacillus subtilis sigma(A) structure and function

The promoter -10 binding region of the Bacillus subtilis sigma(A) factor forms an amphiphilic alpha-helix with three conserved isoleucines located at four-residue intervals. To investigate the structural and functional roles of the three isoleucine residues, we constructed a series of sigA mutants with single and double Ile-to-Ala substitutions on the hydrophobic face of this alpha-helix and isolated intragenic revertants with either same-site or second-site suppressor that partially restores the structural stability and transcription activity of the mutant sigma(A) factors. Our data show that the three conserved isoleucine residues (Ile-194, Ile-198, and Ile-202) are involved in the hydrophobic core packing of sigma(A); they affect differentially and additively the structure and function of sigma(A), with the central isoleucine residue (Ile-198) playing the most important role. By analogy with the crystal structure of a sigma(70) peptide, it is apparent that interdigital interactions exist between the three conserved isoleucine residues and certain hydrophobic amino acids in region 2. 1 of sigma(A). They include at least the van der Waals contacts between Ile-194 and both Leu-145 and Ile-149, between Ile-198 and both Ile-149 and Tyr-153, as well as between Ile-202 and Tyr-153. The same-site suppressors, Val-194 and Val-198, restore the structural stability and transcription activity of sigma(A) by repacking the hydrophobic core of sigma(A). The second-site suppressor (S291F) appears to be allele-specific, but it is not as effective as the same-site suppressors in restoring sigma(A) structure and function.

Identification and characterization of a stress-responsive promoter in the macromolecular synthesis operon of Bacillus subtilis

Bacillus subtilis DB1005 is a temperature-sensitive (Ts) sigA mutant. Induction of sigmaA has been observed exclusively in this mutant harbouring extra copies of the plasmid-borne Ts sigA gene transcriptionally controlled by the P1P2 promoters of the B. subtilis macromolecular synthesis (MMS; rpoD or sigA) operon. Investigation of the mechanisms leading to the induction has allowed us to identify a sigmaB-type promoter, P7, in the MMS operon for the first time. Therefore, at least seven promoters in total are responsible for the regulation of the B. subtilis MMS operon, including the four known sigmaA- and sigmaH-type promoters, as well as two incompletely defined promoters. The P7 promoter was activated in B. subtilis after the imposition of heat, ethanol and salt stresses, indicating that the MMS operon of B. subtilis is subjected to the control of general stress. The significant heat induction of P7 in B. subtilis DB1005 harbouring a plasmid-borne Ts sigA gene can be explained by a model of competition between sigmaA and sigmaB for core binding; very probably, the sigmaB factor binds more efficiently to core RNA polymerase under heat shock. This mechanism may provide a means for the expression of the B. subtilis MMS operon when sigmaA becomes defective in core binding.

Identification of the RNA-binding sites of the triple gene block protein 1 of bamboo mosaic potexvirus

The triple gene block protein 1 (TGBp1) encoded by open reading frame 2 of bamboo mosaic potexvirus (BaMV) was overexpressed in Escherichia coli and purified in order to test its RNA-binding activity. UV crosslinking assays revealed that the RNA-binding activity was present mainly in the soluble fraction of the refolded TGBp1. The binding activity was nonspecific and salt concentration-dependent: activity was present at 0-50 mM NaCl but was almost abolished at 200 mM. The RNA-binding domain was located by deletion mutagenesis to the N-terminal 3-24 amino acids of TGBp1. Sequence alignment analysis of the N-terminal 25 amino acids of the TGBp1 homologues of potexviruses identified three arginine residues. Arg-to-Ala substitution at any one of the three arginines eliminated most of the RNA-binding activity, indicating that they were all critical to the RNA-binding activity of the TGBp1 of BaMV.

Characterization of the Bacillus macerans cyclodextrin glucanotransferase overexpressed in Escherichia coli

Cyclodextrin glucanotransferase (CGTase, EC 2. 4. 1. 19) converts starch and related alpha-1,4-glucans to cyclodextrin (CD). Our previous studies of the enzyme have suggested that E344 on the polypeptide is crucial to the enzyme activity. Mutational analysis of CGTase was performed to confirm this idea. Three mutant CGTases containing either E344D, E344K or E344L substitution were overexpressed in Escherichia coli. However, only the wild-type and E344D CGTases became soluble when expressed at 20 degrees C. These two enzymes were purified to homogeniety from E. coli cells after beta-CD and Ni-NTA affinity chromatographies. The Km values of the authentic Bacillus macerans CGTase (2.10 mM), and of the wild-type (0.58 mM) and E344D (1.05 mM) CGTases purified from E. coli were different. The kcat values of the three CGTases were 99.8, 26.5 and 90.7 s-1, respectively. The percentage of alpha-CD production was 18.4% for the authentic CGTase, 24.9% for the wild-type and 14.5% for the E344D CGTases purified from E. coli. The changes of both the coupling and cyclization activities of CGTase caused by E344D suggest that E344 is important to the catalytic function of CGTase.

Subgenomic RNAs of bamboo mosaic potexvirus-V isolate are packaged into virions

Purified virions of bamboo mosaic potexvirus-V isolate (BaMV-V) were found to contain three major RNA species, the 6.4 kb genomic RNA and two RNAs of 2.0 and 1.0 kb, in addition to associated satellite RNA (0.85 kb). Results of Northern blot hybridization, primer extension analysis and cDNA sequencing showed that the packaged 2.0 and 1.0 kb RNAs of BaMV-V were subgenomic RNAs. In contrast, in the BaMV-O isolate, only genomic RNA was packaged and encapsidated subgenomic RNAs were not detectable. The transcription initiation sites for the 2.0 and 1.0 kb subgenomic RNAs of BaMV-V were located 1 1 and 16 nt upstream of the initiation codon of open reading frames (ORFs) 2 and 5, respectively. The 2.0 and 1.0 kb subgenomic RNAs functioned as messengers for the ORF2 protein and capsid protein, respectively. Packaging of the 1.0 kb subgenomic RNAs resulted in the formation of rod-shaped particles about 70 nm in length. Our results indicate that BaMV isolates have evolved distinctly for packaging of subgenomic RNAs.

RACK1, a receptor for activated C kinase and a homolog of the beta subunit of G proteins, inhibits activity of src tyrosine kinases and growth of NIH 3T3 cells

To isolate and characterize proteins that interact with the unique domain and SH3 and SH2 domains of Src and potentially regulate Src activity, we used the yeast two-hybrid assay to screen a human lung fibroblast cDNA library. We identified RACK1, a receptor for activated C kinase and a homolog of the beta subunit of G proteins, as a Src-binding protein. Using GST-Src fusion proteins, we determined that RACK1 binds to the SH2 domain of Src. Coimmunoprecipitation of Src and RACK1 was demonstrated with NIH 3T3 cells. Purified GST-RACK1 inhibited the in vitro kinase activity of Src in a concentration-dependent manner. GST-RACK1 (2 microM) inhibited the activities of purified Src and Lck tyrosine kinases by 40 to 50% but did not inhibit the activities of three serine/threonine kinases that we tested. Tyrosine phosphorylation on many cellular proteins decreased in 293T cells that transiently overexpressed RACK1. Src activity and cell growth rates decreased by 40 to 50% in NIH 3T3 cells that stably overexpressed RACK1. Flow cytometric analyses revealed that RACK1-overexpressing cells do not show an increased rate of necrosis or apoptosis but do spend significantly more time in G0/G1 than do wild-type cells. Prolongation of G0/G1 could account for the increased doubling time of RACK1-overexpressing cells. We suggest that RACK1 exerts its effect on the NIH 3T3 cell cycle in part by inhibiting Src activity.

The importance of a proper helical structure in the promoter-10 binding region to Bacillus subtilis sigma A structure and function

Two Bacillus subtilis sigA mutants with amino acid substitutions tending to disrupt the structure of the promoter -10 binding helix of B. subtilis sigma A factor were constructed. B. subtilis DB1001 which contained an A197P substitution was very sensitive to temperature elevation. B. subtilis DB1002 had a T199G substitution and was low in growth potential at the elevated temperature. Degradation of sigma A in B. subtilis DB1001 (t(1/2)=63.2 min) and DB1002 (t(1/2)=186.0 min) occurred readily even at 37 degrees C; however, sigma A in B. subtilis DB2 (wild-type) was fairly stable at the same temperature. The activities of both DB1001 and DB1002 sigma A factors on groE promoter (sigma A-type) were lower than those of the wild-type counterpart at both permissive and restrictive temperatures. The failure of a higher sigma A concentration to suppress the Ts phenotype of DB1001 indicated that the temperature sensitivity of B. subtilis DB1001 was due to altered function, rather than insufficient concentration, of sigma A in the cells. Taken together, our results suggest that the helicity of the promoter -10 binding helix is essential to the packing interaction in the hydrophobic core region of sigma A, which helps to maintain the stable and functional sigma A structure.

Subcellular localization of the 28 kDa protein of the triple-gene-block of bamboo mosaic potexvirus

Open reading frame 2 of the bamboo mosaic potexvirus (BaMV) genome encodes a 28 kDa protein, the first of the "triple-gene-block' of BaMV which is believed to play a role in cell-to-cell movement of the virus in host plants. The 28 kDa protein was expressed in Escherichia coli and polyclonal antiserum was raised in a rabbit. Western blot analyses showed that the 28 kDa protein was associated mainly with components in the cell wall and 30000 g pellet fractions of a BaMV-infected leaf homogenate. Immunogold electron microscopy of infected leaf tissues revealed that the 28 kDa protein was associated with electron-dense crystal-line bodies (EDCBs) in the cytoplasm and nuclei. Nuclear EDCBs were found closely associated with nucleoli. Gold-labelled EDCB-like structures were also detected in the cytoplasm, but not within nuclei, in protoplasts up to 48 h post-inoculation. No specific labelling of the 28 kDa protein was found within any cytoplasmic structures or within cell walls.

Mutants of Myxococcus xanthus dsp defective in fibril binding

The dsp mutant of Myxococcus xanthus lacks extracellular fibrils and as a result is unable to undergo cohesion, group motility, or development (J. W. Arnold and L. J. Shimkets, J. Bacteriol. 170:5765-5770, 1983; J. W. Arnold and L. J. Shimkets, J. Bacteriol. 170:5771-5777, 1983; R. M. Behmlander and M. Dworkin, J. Bacteriol. 173:7810-7821, 1991; L. J. Shimkets, J. Bacteriol. 166:837-841, 1986; L. J. Shimkets, J. Bacteriol. 166:842-848, 1986). However, cohesion and development can be phenotypically restored by the addition of isolated fibrils (R. M. Behmlander, Ph.D. thesis, University of Minnesota, Minneapolis, 1994; B.-Y. Chang and M. Dworkin, J. Bacteriol. 176:7190-7196, 1994). As part of our attempts to examine the interaction of fibrils and cells of M. xanthus, we have isolated a series of secondary mutants of M. xanthus dsp in which cohesion, unlike that of the parent strain, could not be rescued by the addition of isolated fibrils. Cells of M. xanthus dsp were mutagenized either by ethyl methanesulfonate or by Tn5 insertions. Mutagenized cultures were enriched by selection of those cells that could not be rescued, i.e., that failed to cohere in the presence of isolated fibrils. Seven mutants of M. xanthus dsp, designated fbd mutants, were isolated from 6,983 colonies; these represent putative fibril receptor-minus mutants. The fbd mutants, like the parent dsp mutant, still lacked fibrils, but displayed a number of unexpected properties. They regained group motility and the ability to aggregate but not the ability to form mature fruiting bodies. In addition, they partially regained the ability to form myxospores. The fbd mutant was backcrossed into the dsp mutant by Mx4 transduction. Three independently isolated transconjugants showed essentially the same properties as the fbd mutants--loss of fibril rescue of cohesion, partial restoration of myxospore morphogenesis, and restoration of group motility. These results suggest that the physical presence of fibrils is not necessary for group motility, myxospore formation, or the early aggregative stage of development. We propose, however, that the perception of fibril binding is required for normal social behavior and development. The dsp fbd mutants (from here on referred to as fbd mutants) open the possibility of isolating and characterizing a putative fibril receptor gene.

Use of hand-held Doppler to identify 'difficult' forearm veins for cannulation

Intravenous cannulation is a necessary procedure in many hospital patients. Some patients are regarded as having 'impossible' veins that are invisible and impalpable despite venous tourniquet. We investigated the use of a hand-held Doppler to identify veins suitable for percutaneous cannulation in such patients. A total of 24 arms in 12 patient volunteers with invisible and impalpable forearm veins was studied by squeezing the ipsilateral hand and using a hand-held 8 MHz Doppler probe on the forearm. Each venous signal was noted and the loudest chosen. Classification as 'good' or 'poor' was made on signal strength. The best signal was then mapped and the direction was indicated by a line on the skin. Each forearm was examined using a colour-flow Duplex. All veins were noted and diameters measured with and without tourniquet. These results were compared with the best veins found by hand-held Doppler. In all, 23 (96%) arms had the largest vein correctly identified by the hand-held Doppler. All 19 (100%) described as 'good' on signal had a diameter of 2.0-4.2 mm (mean 3.2 mm). All 4 (100%) described as 'poor' on Doppler signal had diameters of 1.4-1.7 mm (mean 1.6 mm). Hand-held Doppler, used as described, can accurately identify forearm veins larger than 2.0 mm in diameter in patients with invisible and impalpable veins with venous tourinquet. These veins should be amenable to percutaneous cannulation.

Isolated fibrils rescue cohesion and development in the Dsp mutant of Myxococcus xanthus

Extracellular fibrils are involved in cell cohesion and cell development in Myxococcus xanthus. One group of social motility mutants, Dsp, is unable to produce extracellular fibrils; these mutants also lose the abilities to cohere and to develop. Extracellular fibrils isolated from vegetative wild-type cells and added to Dsp cells fully restored the abilities of these cells to cohere and to undergo normal morphological development. The fibrils thus mimic the ability of intact, wild-type cells to carry out the same rescue. Optimal cohesion rescue by fibrils required calcium and magnesium ions, did not require protein synthesis, but was energy dependent, i.e., sodium azide and sodium cyanide blocked rescue. Cohesion rescue was also blocked by the diazo dye Congo red. Cohesion rescue is genus specific, i.e., isolated fibrils did not cause the cohesion of Pseudomonas aeruginosa, Bacillus subtilis, Proteus mirabilis, Escherichia coli, or the related myxobacterium Stigmatella aurantiaca. Developmental rescue of Dsp by isolated fibrils included aggregation, fruiting body formation, and myxospore morphogenesis. Developmental gene expression in the Dsp mutant was only partially rescued by the isolated fibrils.

The response of a Bacillus subtilis temperature-sensitive sigA mutant to heat stress

The mutant sigA allele of Bacillus subtilis DB1005 was confirmed to be temperature sensitive (ts) and transferable among strains of B. subtilis by chromosomal transformation and gene conversion. This ts sigA allele had a pleiotropic effect on gene expression of DB1005. The induction of certain heat shock proteins in DB1005 was markedly less significant than that observed in the wild-type strain (DB2) under heat stress. In contrast, some proteins required for coping with oxidative stress and glucose starvation were induced abruptly in DB1005 but not in DB2. Heat induction of the groEL gene in vivo at both transcription and translation levels was much lower in DB1005 than in DB2. Besides, the putative sigma A-type promoter from the groESL operon of B. subtilis was able to be transcribed by the reconstituted sigma A RNA polymerase in vitro at both 37 and 49 degrees C. These results strongly suggest that the expression of the groEL gene of B. subtilis under heat stress is regulated at least in part by sigma A at the level of transcription. Our results also showed that DB1005 did not respond too differently from the wild type to ethanol stress, except after a relatively long exposure.

Nucleotide sequence of the coat protein coding region of the potyvirus tobacco vein-banding mosaic virus

The sequence of the 3' 1184 nucleotides of tobacco vein-banding mosaic virus (TVBMV) genome has been determined. It contains a single open reading frame which encompasses the whole of the coat protein of TVBMV. The sequence of the first 20 amino acids at the N-terminal region of the coat protein has also been determined chemically to be GDDQTVDAGKNVQSNQKQRN. The sequence matches the translation product of the open reading frame starting with amino acid-271; a glycine residue. Thus the coat protein of TVBMV has a calculated M(r) of 30,210. The 3' non-coding region of TVBMV is 185 nucleotides in length. Sequence alignment of the coat proteins or the 3' non-coding regions from TVBMV and other reported potyviruses indicated that TVBMV is a separate species of the potyvirus genus.

Conformational properties of Bacillus subtilis RNA polymerase sigma A factor during transcription initiation

By the use of a partial proteolysis method and Western-blot analysis, the conformational properties of Bacillus subtilis sigma A factor in the transcription initiation stage were studied. From a comparison of the trypsin-digestion patterns of free sigma A and of sigma A associated with core enzyme, it was found that the production of 45 kDa sigma A tryptic-derived fragment was enhanced when sigma A was associated with the core enzyme. More importantly, a 40 kDa sigma A tryptic-derived fragment was found exclusively in this associated state. Based on the change of the digestion kinetics when producing the 45 kDa tryptic fragment and the generation of this new 40 kDa tryptic fragment from sigma A, it was apparent that a conformation change of sigma A occurred during the association of sigma A with the core enzyme. Also, similar patterns were found for the sigma A present in the holoenzyme-promoter DNA complex. These findings suggest that no further distinctive conformational change of sigma A occurs at the step of RNA polymerase holoenzyme and promoter DNA complex formation. Trypsin-digestion patterns of sigma A in different RNA polymerase holoenzyme and promoter DNA complexes were also studied. The presence of similar trypsin digestion-patterns of sigma A in those complexes strongly supports the idea that a similar sigma A conformation is used in the recognition of different sigma A-type promoters and the formation of different open complexes.

Effects of amino acid substitutions in the promoter -10 binding region of the sigma A factor on growth of Bacillus subtilis

On the bases of structural and functional information about the Bacillus subtilis sigma A protein and the techniques of site-directed mutagenesis, we constructed a B. subtilis sigA mutant (DB1005) which grows normally at 37 degrees C but is sensitive to higher temperatures. DNA sequencing analyses revealed that DB1005 has Ile-198-->Ala and Ile-202-->Ala amino acid substitutions in the alpha-helix of the 2.4 region of the sigma A protein. Western blotting (immunoblotting) revealed that this mutant sigma A protein is stable at both 37 and 49 degrees C. These results suggest that Ile-198 and Ile-202 separately or in combination are critical for the sigma A protein to be functional at the restrictive temperature.

Cell surface modifications induced by calcium ion in the myxobacterium Stigmatella aurantiaca

Calcium ion induces in the myxobacterium Stigmatella aurantiaca the ability to glide on solid surfaces and to become cohesive (D. F. Gilmore and D. White, J. Bacteriol. 161:113-117, 1985; B. J. Womack, D. F. Gilmore, and D. White, J. Bacteriol. 171:6093-6096, 1989). The addition of calcium ion to the growth medium resulted in the formation of extracellular fibrils, the appearance in the membrane fractions of a 30-kDa protein, and the accumulation in a low-speed centrifugal pellet of 10 polypeptides that cross-reacted with affinity-purified antibody to one of the polypeptides. One of the polypeptides, a 55-kDa protein, was present in the membrane fraction of control cells not incubated with calcium ion and was apparently translocated to the extracellular matrix during incubation in medium containing calcium ion. The 55-kDa protein was immunologically related to a 65-kDa protein located on the fibrils of another myxobacterium, Myxococcus xanthus.

The interaction between Bacillus subtilis sigma-A (sigma A) factor and RNA polymerase with promoters

The P2 promoter from Bacillus subtilis sigma-A (sigma A) operon and the strong phi 29 phage G3b promoter were used to study their interactions with free sigma A and with RNA polymerase holoenzymes (E sigma A and E sigma 70). No binding of free sigma A to the tested promoters was observed, suggesting that the B subtilis free sigma A does not bind promoter by itself for the initiation of RNA transcription. Different footprints of B subtilis RNA polymerase holoenzyme (E sigma A) on the P2 and G3b promoters were detected. The footprint on the P2 promoter is mainly in the -10 downstream region of the bottom strand (noncoding strand) DNA and limited on the top strand (coding strand), whereas the footprints on both strands of the G3b promoter are very clear. These results suggest that the footprint regions of RNA polymerase on a promoter and the strength of its binding to the promoter depend on the properties of the specific promoter DNA sequence. It also suggests that the -10 and its downstream regions are more important than the -35 region for the formation of the E sigma A-P2 promoter open complex. Footprints of B subtilis E sigma A and E coli E sigma 70 on the same G3b promoter are very similar on the top strand but different on the bottom strand, with the footprint being about 17 bases wider (-4 to +13) in the case of E coli E sigma 70. Since this region contains most of the bases involved in promoter DNA melting, we suggest that E coli and B subtilis RNA polymerases have different efficiency in forming the open complex with heterologous promoter DNA during initiation of transcription.

Overproduction, purification, and characterization of Bacillus subtilis RNA polymerase sigma A factor

By use of a T7 expression system, large amounts of active Bacillus subtilis RNA polymerase sigma A factor were produced in Escherichia coli cells. This overproduced protein was found in the form of inclusion bodies and constituted 40% of the total cellular protein. Because of the ease of isolation of the inclusion bodies and the acidic properties of sigma A, the protein was purified to more than 99% purity and the yield was about 90 mg/liter of culture. Gel mobility, antigenicity, specificity of promoter recognition, and N-terminal amino acid sequence of the overproduced sigma were found to be the same as those of native sigma A. Partial proteolysis analysis of sigma A protein suggested the presence of a protease-sensitive surface region in the C-terminal part of the sigma A protein. The promoter -10 binding region of sigma A was less sensitive to proteases and was probably involved in a hydrophobic, tightly folded domain of sigma A protein.