中国石松类和蕨类植物的多样性与地理分布

物种编目及其科属系统排列是了解生物多样性的基础, 本文采用Flora of China使用的分类系统, 结合最新分子分类学研究成果以及近几年发表的新资料, 对中国石松类和蕨类植物多样性和地理分布数据进行了统计和分析。结果表明中国共有石松类和蕨类植物40科178属2,147种5个亚种118个变种, 其中特有种839个, 占总种数的39.08%。种数最多的5个科依次为鳞毛蕨科(505种, 含种下单位, 下同)、蹄盖蕨科(323种)、水龙骨科(280种)、凤尾蕨科(266种)和金星蕨科(209种); 种数最多的5个属依次为耳蕨属(Polystichum, 209种)、鳞毛蕨属(Dryopteris, 176种)、蹄盖蕨属(Athyrium, 137种)、双盖蕨属(Diplazium, 98种)和凤尾蕨属(Pteris, 97种)。在地理分布上, 种数排名前5的省份为云南(1,365种)、四川(875种)、贵州(838种)、广西(785种)和台湾(779种)。含中国特有石松类和蕨类植物的科属中, 排前3位的科分别为鳞毛蕨科(257种)、蹄盖蕨科(169种)和凤尾蕨科(113种); 排前3位的属为耳蕨属(140种)、蹄盖蕨属(82种)和鳞毛蕨属(61种)。     

Diterpenoids and triterpenoids from Euphorbia guyoniana

Two new compounds with tigliane and cycloartane skeletons: 4,12-dideoxy(4alpha)phorbol-13-hexadecanoate (1) and 24-methylenecycloartane-3,28-diol (2), respectively, in addition of four known diterpenoids and 13 triterpenoids: 3-benzoyloxy-5,15-diacetoxy-9,14-dioxojatropha-6(17),11-diene (4), ent-abieta-8(14),13(15)-dien-16,12-olide (5), ent-8alpha,14alpha-epoxyabieta-11,13(15)-dien-16,12-olide (6), ent-3-hydroxyatis-16(17)-ene-2,14-dione (7), 3beta-hydroxytaraxer-14-en-28-oic acid (8), beta-sitosteryl-3beta-glucopyranoside-6'-O-palmitate (9), multiflorenyl acetate (10), multiflorenyl palmitate (11), peplusol (12), 24-methylenecycloartanol (3), lanosterol (13), euferol (14), butyrospermol (15), cycloartenol (16), obtusifoliol (17), cycloeucalenol (18) and beta-sitosterol (19), were isolated from the roots of Euphorbia guyoniana. Their structures were established on the basis of physical and spectroscopic analysis, including 1D and 2D homo- and heteronuclear NMR experiments (COSY, HSQC, HMBC and NOESY) and by comparison with the literature data.     

Genetic and environmental analysis of dystocia and stillbirths in draft horses

Genetic parameters and environmental factors were estimated for foaling ease (FE) and stillbirths (SBs) in four breeds of draft horses based on 11 229, 38 877, 35 764 and 13 274 FE and SB scores recorded between 1998 and 2010 for Ardennais (A), Breton (B), Comtois (C) and Percheron (P), respectively. Incidences for the three FE categories were: easy or without help 91.0% (A) to 95.4% (B), difficult 3.4% (B) to 7.1% (A) and intervention of a veterinarian 1.1% (B) to 1.9% (A). The frequency of SB ranged between 5.4% (B) and 9.4% (A). A multiple-trait threshold animal model was used that included the effects of sex of foal, region, month, year of foaling, combined maternal age and parity, direct genetic, maternal genetic and permanent environments. Estimates were obtained using Markov Chain Monte Carlo Gibbs sampling. The most unfavourable effect was first parity, which decreased the probability of easy foaling to 78.6% for A and 88.3% for B. Interaction with age showed that the risk for first foaling for mares aged 3 years was higher than at 4 or 5 to 9 years. This was also observed for SB with an increased probability of SB at first foaling of 17.9% (A) or 9.6% (B). The most unfavourable month was found to be the most frequent month for foaling (April) and not the most demanding months weather-wise (winter). For FE, direct heritabilities were A 0.27 (0.06), B 0.14 (0.03), C 0.18 (0.03) and P 0.18 (0.04), and maternal heritabilities were A 0.25 (0.06), B 0.19 (0.04), C 0.12 (0.03) and P 0.21 (0.06). Genetic correlations between direct and maternal genetic effects were A −0.29 (0.14), B −0.39 (0.12), C −0.09 (0.14) and P −0.54 (0.17). For SB, direct heritabilities were A 0.52 (0.09), B 0.42 (0.04), C 0.28 (0.04) and P 0.39 (0.05), and maternal heritabilities were A 0.25 (0.05), B 0.10 (0.02), C 0.07 (0.02) and P 0.14 (0.02). Genetic correlations between direct and maternal genetic effects were A −0.85 (0.06), B −0.63 (0.06), C −0.64 (0.11) and P −0.69 (0.06). Direct genetic correlations between FE and SB traits were A 0.60 (0.10), B 0.58 (0.10), C 0.36 (0.10) and P 0.29 (0.15). Maternal genetic correlations between FE and SB traits were A 0.67 (0.10), B 0.47 (0.13), C 0.28 (0.15) and P 0.39 (0.15). These estimates are posterior means of the Gibbs samples and are within the upper limits of comparable results reported in cattle.     

Chemical evolution and the origin of life

This bibliography is the seventeenth annual supplement to the comprehensive bibliography on the same subject which was published in Space Life Sci. 2(1970), 225-295; 3(1972), 293-304; 4(1973), 309-329 and in Origins of Life 5(1974), 505-527; 6(1975), 285-300; 7(1976), 75-85; 8(1977), 59-66; 9(1978), 67-74; 10(1980), 69-87; 10(1980), 379-404; 11(1981), 273-288; 12(1982), 93-118; 13(1983), 61-80; 15(1984), 55-69; 17(1987), 171-184; 17(1987), 185-206.     

Synthesis of variously oxidized abietane diterpenes and their antibacterial activities against MRSA and VRE

Variously oxidized 12 natural abietanes, 6,7-dehydroferruginol methyl ether (3), ferruginol (5), 11-hydroxy-12-oxo-7,9(11),13-abietatriene (7), royleanone (9), demethyl cryptojaponol (12), salvinolone (14), sugiol methyl ether (16), sugiol (17), 5,6-dehydrosugiol methyl ether (19), 5,6-dehydrosugiol (20), 6beta-hydroxyferruginol (23), and taxodione (25) were synthesized. Antimicrobial activities of synthesized phenolic diterpenes and their related compounds against MRSA and VRE were evaluated. Phenols (12-hydroxyabieta-8,11,13-trien-6-one 22 and 23), catechols (12 and 14) and taxodione 25 showed potent activity with 4-10 microg/mL of MIC against MRSA and 4-16 microg/mL of MIC against VRE. (-)-Ferruginol showed more potent activity than natural type (+)-ferruginol. Quinone methide 7 showed the most potent activity with 0.5-1 microg/mL of MIC against both MRSA and VRE.     

Identification and functions of amino acid residues in PotB and PotC involved in spermidine uptake activity

Amino acid residues on PotB and PotC involved in spermidine uptake were identified by random and site-directed mutagenesis. It was found that Trp(8), Tyr(43), Trp(100), Leu(110), and Tyr(261) in PotB and Trp(46), Asp(108), Glu(169), Ser(196), Asp(198), and Asp(199) in PotC were strongly involved in spermidine uptake and that Tyr(160), Glu(172), and Leu(274) in PotB and Tyr(19), Tyr(88), Tyr(148), Glu(160), Leu(195), and Tyr(211) in PotC were moderately involved in spermidine uptake. Among 11 amino acid residues that were strongly involved in spermidine uptake, Trp(8) in PotB was important for insertion of PotB and PotC into membranes. Tyr(43), Trp(100), and Leu(110) in PotB and Trp(46), Asp(108), Ser(196), and Asp(198) in PotC were found to be involved in the interaction with PotD. Leu(110) and Tyr(261) in PotB and Asp(108), Asp(198), and Asp(199) in PotC were involved in the recognition of spermidine, and Trp(100) and Tyr(261) in PotB and Asp(108), Glu(169), and Asp(198) in PotC were involved in ATPase activity of PotA. Accordingly, Trp(100) in PotB was involved in both PotD recognition and ATPase activity, Leu(110) in PotB was involved in both PotD and spermidine recognition, and Tyr(261) in PotB was involved in both spermidine recognition and ATPase activity. Asp(108) and Asp(198) in PotC were involved in PotD and spermidine recognition as well as ATPase activity. These results suggest that spermidine passage from PotD to the cytoplasm is coupled to the ATPase activity of PotA through a structural change of PotA by its ATPase activity.     

A comparison between learning style preferences and sex, status, and course performance

Students have learning style preferences that are often classified according to their visual (V), aural (A), read-write (R), and/or kinesthetic (K) sensory modality preferences (SMP). The purposes of this investigation were to compare student perceived and assessed SMPs and examine the associations between those SMPs and status (i.e., undergraduates vs. graduates), sex, and course performance. Students from the fall 2009 APK 3110 and APK 6116 Exercise Physiology courses were asked to indicate their perceived SMPs and complete the standard VARK SMP assessment. There were 64 student respondents: 50 undergraduates and 14 graduates (40 women and 24 men). According to the perceived SMP results, the largest number of respondents chose V (36%), followed by R (28%), K (19%), and A (17%). In terms of assessed SMPs, the largest number of respondents were classified as VARK (37%), followed by R (14%), AK (11%), K (8%), VK (6%), ARK (6%), A (5%), VAK (3%), RK (3%), V (2%), AR (2%), and VRK (2%). Nearly two-thirds of the respondents correctly matched their perceived and dominant assessed SMP. There was no statistical association between SMP and status. There was a very nearly significant relationship between sex and both perceived (χ(2) = 7.18, P = 0.06) and assessed (χ(2) = 17.36, P = 0.09) SMP. Finally, there was a significant relationship between perceived SMP and course scores (P = 0.01 by ANOVA). Post hoc tests revealed that the K group scored significantly lower than the other three modality groups.     

Tetralones and flavonoids from Pyrola calliantha

Two new tetralones, pyrolones A (1) and B (2), and a new flavonol glycoside, 2'-O-(4-hydroxybenzoyl)hyperin (3), were isolated from Pyrola calliantha (whole plant), together with six structurally related compounds, including 2'-O-galloylhyperin (4), hyperin (5), formononetin (6), quercetin 3-O-alpha-L-arabinopyranoside (7), quercetin 3-O-alpha-L-arabinofuranoside (8), and kaempferol 3-O-beta-D-galactopyranoside (9). The structures and absolute configurations of the new compounds were elucidated on the basis of spectroscopic (UV, ORD, CD, NMR) and mass-spectrometric (HR-ESI-MS) analyses.     

Evaluation of Essential and Toxic Trace Elements in Pseudoexfoliation Syndrome and Pseudoexfoliation Glaucoma

Pseudoexfoliation syndrome (PEX), an age-related disorder of the eye, is associated with significant ophthalmic morbidity and can lead to pseudoexfoliation glaucoma (PEG). The etiology of this disorder has not been clearly understood. Trace elements have been suggested to have roles in the pathogenesis of several disorders. This study aimed to determine whether trace element levels have a role in the development of PEX and/or PEG. Levels of zinc (Zn), copper (Cu), selenium (Se), manganese (Mn), chromium (Cr), cobalt (Co), molybdenum (Mo), nickel (Ni), vanadium (V), arsenic (As), aluminum (Al), mercury (Hg), cadmium (Cd), and strontium (Sr) were determined in serum samples of 32 cases of PEX, 30 cases of PEG, and 32 control subjects using inductively coupled plasma–mass spectrometry. Mn, Mo, and Hg concentrations were found to be significantly increased in patients with PEX. Logistic regression revealed Mn and Hg as the strongest determinants of PEX and Mo as the strongest determinant of PEG in the studied Turkish subjects. Levels of Mn, Cr, Co, Mo, Al, Hg, Sr, Ni, V, and As were determined for the first time in these ophthalmological disorders. Increased levels of serum Mn, Mo, and Hg suggest a possible role of these elements in the pathobiology of PEX.     

Antiinflammatory triterpenoids and steroids from Ganoderma lucidum and G. tsugae

The antiinflammatory properties of triterpenoids and steroids from both Ganoderma lucidum and Ganoderma tsugae were studied. Twelve compounds, including ergosta-7,22-dien-3beta-ol (1), ergosta-7,22-dien-3beta-yl palmitate (2), ergosta-7,22-dien-3-one (3), ergosta-7,22-dien-2beta,3alpha,9alpha-triol (4), 5alpha,8alpha-epidioxyergosta-6,22-dien-3beta-ol (5), ganoderal A (6), ganoderal B (7), ganoderic aldehyde A (8), tsugaric acid A (9), 3-oxo-5alpha-lanosta-8,24-dien-21-oic acid (10), 3alpha-acetoxy-5alpha-lanosta-8,24-dien-21-oic acid ester beta-d-glucoside (11), and tsugaric acid B (12), were assessed in vitro by determining their inhibitory effects on the chemical mediators released from mast cells, neutrophils, and macrophages. Compound 10 showed a significant inhibitory effect on the release of beta-glucuronidase from rat neutrophils stimulated with formyl-Met-Leu-Phe (fMLP)/cytochalasin B (CB) whereas compound 9 significantly inhibited superoxide anion formation in fMLP/CB-stimulated rat neutrophils. Compound 10 also exhibited a potent inhibitory effect on NO production in lipopolysaccharide (LPS)/interferon-gamma (IFN-gamma)-stimulated N9 microglial cells. Moreover, compound 9 was also able to protect human keratinocytes against damage induced by ultraviolet B (UV B) light, which indicated 9 could protect keratinocytes from photodamage.     

Structure and function of polyamine-amino acid antiporters CadB and PotE in Escherichia coli

The structure and function of a cadaverine-lysine antiporter CadB and a putrescine-ornithine antiporter PotE in Escherichia coli were evaluated using model structures based on the crystal structure of AdiC, an agmatine-arginine antiporter, and the activities of various CadB and PotE mutants. The central cavity of CadB, containing the substrate binding site, was wider than that of PotE, mirroring the different sizes of cadaverine and putrescine. The size of the central cavity of CadB and PotE was dependent on the angle of transmembrane helix 6 (TM6) against the periplasm. Tyr(73), Tyr(89), Tyr(90), Glu(204), Tyr(235), Asp(303), and Tyr(423) of CadB, and Cys(62), Trp(201), Glu(207), Trp(292), and Tyr(425) of PotE were strongly involved in the antiport activities. In addition, Trp(43), Tyr(57), Tyr(107), Tyr(366), and Tyr(368) of CadB were involved preferentially in cadaverine uptake at neutral pH, while only Tyr(90) of PotE was involved preferentially in putrescine uptake. The results indicate that the central cavity of CadB consists of TMs 2, 3, 6, 7, 8, and 10, and that of PotE consists of TMs 2, 3, 6, and 8. These results also suggest that several amino acid residues are necessary for recognition of cadaverine in the periplasm because the level of cadaverine is much lower than that of putrescine in the periplasm at neutral pH. All the amino acid residues identified as being strongly involved in both the antiport and uptake activities were located on the surface of the transport path consisting of the central cavity and TM12.     

Chemical composition and biological activity of Nepeta parnassica oils and isolated nepetalactones

Essential oils of Nepeta parnassica, collected at different developmental stages, were analyzed by means of GC/MS. From the fifty-five identified constituents in samples A and B, representing 94.8% and 98.7% of the oils respectively, 4a(alpha),7alpha,7alpha(beta)-nepetalactone (22.0%), 1,8-cineole (21.1%), alpha-pinene (9.5%) and 4a(alpha),7,beta,7alpha(beta)-nepetalactone (7.9%) were the major components of sample A (vegetative stage), whereas in sample B (flowering stage) the main contributors were 1,8-cineole (34.6%), 4a(alpha),7alpha,7a(alpha)-nepetalactone (17.3%), alpha-pinene (11.4%) and 4a(alpha),7alpha,7alpha(beta)-nepetalactone (8.9%). The oils were tested on human health important insects such as the Pogonomyrmex sp. ants and the Culex pipiens molestus mosquitoes with promising results on insect repellency/toxicity.     

Synthesis and study of cyclic and linear analogs of neurotensin

New cyclic analogues of neurotensin (NT): [cyclo (13----8), Gly8]NT-(8-13), [cyclo (13----7), Gly7]NT-(7-13), [cyclo (13----5 epsilon), Lys5]NT-(5-13), [cyclo (13----4 epsilon), Lys4]NT-(4-13), and their linear precursors have been synthesized. The latter (protected linear compounds) were prepared by solid-phase peptide synthesis, and cyclization was attained by using diphenylphosphoryl azide. Cyclization of C-terminal hexa- and octapeptide fragments of NT was found to lead to cycloanalogues possessing high depressor activity. As judged by CD spectral data in aqueous solution, the cyclohexapeptide analogue has a relatively rigid conformation different from its linear counter-part and the NT-(9-13) fragment, whereas NT, its cyclohepta- and cyclononapeptides have random structure.     

Studies of the cellular and free lipopolysaccharides form Neisseria canis and N. subflava.

Cellular and free lipopolysaccharides (LPS) obtained from Neisseria canis and N. subflava were essentially identical. Both cellular and free lipopolysaccharides contained O-polysaccharides of the following composition: L-rhamnose (46 mol), D-glucose (16 mol), L-glycero-D-manno-heptose (2 mol), ethanolamine (2 mol), 3-deoxy-D-manno-octulosonic acid (1 mol), and phosphate (1.5 mol). The core oligosaccharide, which was common to the cellular and free LPS of both organisms, contained L-rhamnose (4 mol), D-glucose (2 mol), L-glycero-D-manno-heptose (2 mol), 3-deoxy-D-manno-octulosonic acid (1 mol), ethanolamine (2 mol), and phosphate (1.5 mol). Accumulated results on LPS composition and structure indicated that Neisseria perflava, N. subflava, and N. flava could not be combined into a single species. On the basis of its nutritional requirements and LPS structure, N. canis could be considered a strain of N. subflava.     

Purification and characterization of a receptor for human parathyroid hormone and parathyroid hormone-related peptide

The human parathyroid hormone (PTH) receptor (hPTH1R), containing a 9-amino acid sequence of rhodopsin at its C terminus, was transiently expressed in COS-7 cells and solubilized with 0.25% n-dodecyl maltoside. Approximately 18 microg of hPTH1R were purified to homogeneity per mg of crude membranes by single-step affinity chromatography using 1D4, a monoclonal antibody to a rhodopsin epitope. The N terminus of the hPTH1R is Tyr(23), consistent with removal of the 22-amino acid signal peptide. Comparisons of hPTH1R by quantitative immunoblotting and Scatchard analysis revealed that 75% of the receptors in membrane preparations were functional; there was little, if any, loss of functional receptors during purification. The binding affinity of the purified hPTH1R was slightly lower than membrane-embedded hPTH1R (K(d) = 16.5 +/- 1.3 versus 11.9 +/- 1.9 nm), and the purified receptors bound rat [Nle(8,21),Tyr(34)]PTH-(1-34)-NH(2) (PTH-(1-34)), and rat [Ile(5),Trp(23),Tyr(36)]PTHrP-(5-36)-NH(2) with indistinguishable affinity. Maximal displacement of (125)I-PTH-(1-34) binding by rat [alpha-aminoisobutyric acid (Aib)(1,3),Nle(8),Gln(10),Har(11),Ala(12),Trp(14),Arg(19),Tyr(21)]PTH-(1-21)-NH(2) and rat [Aib(1,3),Gln(10),Har(11),Ala(12),Trp(14)]PTH-(1-14)-NH(2) of 80 and 10%, respectively, indicates that both N-terminal and juxtamembrane ligand binding determinants are functional in the purified hPTH1R. Finally, PTH stimulated [(35)S]GTP gamma S incorporation into G alpha(s) in a time- and dose-dependent manner, when recombinant hPTH1R, G alpha(s)-, and beta gamma-subunits were reconstituted in phospholipid vesicles. The methods described will enable structural studies of the hPTH1R, and they provide an efficient and general technique to purify proteins, particularly those of the class II G protein-coupled receptor family.     

Zinc supplementation and cardiovascular disease risk factors: A GRADE-assessed systematic review and dose-response meta-analysis

Background and objectiveA deficit in zinc has been related to a higher probability of developing cardiovascular diseases (CVDs). The anti-inflammatory and anti-oxidative capabilities of zinc may have a wide range of therapeutic impacts on CVDs. We conducted a comprehensive systematic review and meta-analysis of the possible impacts that zinc supplementation may have on the risk factors associated with CVDs.MethodsTo identify eligible randomized clinical trials (RCTs) evaluating the effects of zinc supplementation on CVDs risk factors, electronic databases including PubMed, Web of Science, and Scopus were systematically searched up to January 2023. The heterogeneity of trials was checked using the I² statistic. According to the heterogeneity tests, random effects models were estimated and pooled data were defined as the weighted mean difference (WMD) with a 95% confidence interval (CI).ResultsOf 23165 initial records, 75 studies that met inclusion criteria were analyzed in this meta-analysis. The pooled findings indicated the significant lowering effects of zinc supplementation on triglycerides (TG), total cholesterol (TC), fasting blood glucose (FBG), Hemoglobin A1C (HbA1C), Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), C-reactive protein (CRP), interleukin-6 (IL-6), Tumor necrosis factor-α (TNF-α), nitric oxide (NO), malondialdehyde (MDA), total antioxidant capacity (TAC), and glutathione (GSH), with no noticeable effects on low-density lipoprotein (LDL), high-density lipoprotein (HDL), insulin, systolic blood pressure (SBP), diastolic blood pressure (DBP), aspartate transaminase (AST), and Alanine aminotransferase (ALT).ConclusionOverall, zinc supplementation may boost recognized coronary risk factors that contribute to the development of CVDs. Future research should be conducted to bolster our results.     

Plant biochemistry of xenobiotics: isolation and properties of soybean O- and N-glucosyl and O- and N-malonyltransferases for chlorinated phenols and anilines.

O-Glucosyltransferase (O-GT), O-malonyltransferase (O-MAT), N-glucosyltransferase (N-GT), and N-malonyltransferase (N-MAT) activities have been detected in cultured soybean cells, using pentachlorophenol and 3,4-dichloroaniline as xenobiotic standard substrates. The O-GT was purified approximately 1000-fold, and the N-MAT approximately 70-fold. There was an extensive copurification of O-GT and O-MAT. The following functional molecular weight values were obtained, 47 kDA (O-GT), 48 kDA (O-MAT) 43 kDa (N-GT), and 48 kDa (N-MAT). O-GT and N-MAT appeared to be monomeric polypeptides with isoelectric points of approximately 4.8 and approximately 6.1, respectively. The O-GT, N-GT, and N-MAT activities had marked substrate specificities for chlorinated aromatic xenobiotics and thus illustrate the existence of plant isoenzymes with specificity for xenobiotics.     

Causal association between human papilloma virus infection and head and neck and esophageal squamous cell carcinoma

HPVs commonly cause proliferative lesions of squamous epithelium, and infection with certain HPV types carries a high risk of malignant transformation. We used molecular techniques to detect and type HPV in papillomas and carcinomas in the oral cavity and esophagus. DNA was extracted from 150 fresh or paraffin embedded biopsy specimens, and analyzed for HPV by PCR with 15 sets of consensus primers directed to conserved regions of L1 gene, three sets of HPV16E6 primers (specific for the HPV 16 prototype and L83V variant), and sets of primers specific for the E6 gene of other mucosa type HPVs including HPV 6, 11, 16, 18, 52, 58, 66 and 73. Overall, HPV sequences were detected in 61 of 150 specimens. HPV DNA sequences were detected in 16/32 specimens in the oropharyngeal region, in 13/36 specimens in larynx and 32/82 specimens in esophagus. Papillomas contained only the episomal form of HPV 16. In the esophagus, the most common type was HPV 73. In all specimens examined, HPV 6/11 (4/150), HPV 16 (23/150), HPV 35 (1/150), HPV 45 (1/150), HPV 54 (1/150), HPV 58 (1/150), HPV 61 (1/150), HPV 66 (1/150), HPV 68 (2/150), HPV 70 (3/150), HPV 72 (1/150), HPV 73 (16/150), double HPV infection (2/150), and unidentified HPV type (4/150) was detected. Interestingly, HPV was found in all verrucous carcinomas and in 18/22 basaloid squamous cell carcinomas. HPV16E6 T350G mutant were observed only in two of eight carcinomas. Using correspondence analysis, a segregation of specific virus types in specific clinico-pathologic lesions (verrucous carcinoma and basaloid squamous cell carcinoma) was proved. It was shown that the relative rates of the HPV positive tumors were significantly higher in women than in men. The synergic action of mucosal irritation and HPV infection may be necessary for the development of the papillomas and the specific types of carcinomas in the oral cavity and in the esophagus.     

The flexible and clustered lysine residues of human ribonuclease 7 are critical for membrane permeability and antimicrobial activity

The ubiquitous ribonucleases (RNases) play important roles in RNA metabolism, angiogenesis, neurotoxicity, and antitumor or antimicrobial activity. Only the antimicrobial RNases possess high positively charged residues, although their mechanisms of action remain unclear. Here, we report on the role of cationic residues of human RNase7 (hRNase7) in its antimicrobial activity. It exerted antimicrobial activity against bacteria and yeast, even at 4 degrees C. The bacterial membrane became permeable to the DNA-binding dye SYTOX(R) Green in only a few minutes after bactericidal RNase treatment. NMR studies showed that the 22 positively charged residues (Lys(18) and Arg(4)) are distributed into three clusters on the surface of hRNase7. The first cluster, K(1),K(3),K(111),K(112), was located at the flexible coil near the N terminus, whereas the other two, K(32),K(35) and K(96),R(97),K(100), were located on rigid secondary structures. Mutagenesis studies showed that the flexible cluster K(1),K(3),K(111),K(112), rather than the catalytic residues His(15), Lys(38), and His(123) or other clusters such as K(32),K(35) and K(96),R(97),K(100), is critical for the bactericidal activity. We suggest that the hRNase7 binds to bacterial membrane and renders the membrane permeable through the flexible and clustered Lys residues K(1),K(3),K(111),K(112). The conformation of hRNase7 can be adapted for pore formation or disruption of bacterial membrane even at 4 degrees C.     

Association of the physical and chemical properties and the cytotoxicity of metal oxide nanoparticles: metal ion release, adsorption ability and specific surface area

Association of cellular influences and physical and chemical properties were examined for 24 kinds of industrial metal oxide nanoparticles: ZnO, CuO, NiO, Sb(2)O(3), CoO, MoO(3), Y(2)O(3), MgO, Gd(2)O(3), SnO(2), WO(3), ZrO(2), Fe(2)O(3), TiO(2), CeO(2), Al(2)O(3), Bi(2)O(3), La(2)O(3), ITO, and cobalt blue pigments. We prepared a stable medium dispersion for each nanoparticle and examined the influence on cell viability and oxidative stress together with physical and chemical characterizations. ZnO, CuO, NiO, MgO, and WO(3) showed a large amount of metal ion release in the culture medium. The cellular influences of these soluble nanoparticles were larger than insoluble nanoparticles. TiO(2), SnO(2), and CeO(2) nanoparticles showed strong protein adsorption ability; however, cellular influences of these nanoparticles were small. The primary particle size and the specific surface area seemed unrelated to cellular influences. Cellular influences of metal oxide nanoparticles depended on the kind and concentrations of released metals in the solution. For insoluble nanoparticles, the adsorption property was involved in cellular influences. The primary particle size and specific surface area of metal oxide nanoparticles did not affect directly cellular influences. In conclusion the most important cytotoxic factor of metal oxide nanoparticles was metal ion release.