Development of a multiplex PCR for the identification of Staphylococcus genus and four staphylococcal species isolated from food

AIMS: To develop a multiplex PCR that allows the identification of bacteria belonging to the Staphylococcus genus and in particular to the species Staphylococcus xylosus, S. saprophyticus, S. epidermidis and S. aureus isolated from food manufacturing plants. METHODS AND RESULTS: Five primer pairs were used in the multiplex PCR, one specific to the Staphylococcus genus and four specific to S. xylosus, S. saprophyticus, S. epidermidis and S. aureus species. All the 31 Staphylococcus reference strains yielded a specific PCR product with the genus-specific primers. Staphylococcus xylosus, S. saprophyticus, S. epidermidis and S. aureus gave a specific PCR fragment with the corresponding species-specific primers. No amplification with the Kocuria, Macrococcus and Micrococcus strains was observed in our conditions. This multiplex PCR was performed on 30 strains of Gram-positive cocci isolated from different workshops and fermented sausages. Among them, 28 belonged to the Staphylococcus genus and 14 were identified to S. saprophyticus, four to S. xylosus, two to S. aureus and one to S. epidermidis. CONCLUSIONS: This multiplex PCR provided reliable and repeatable PCR results. It allowed the identification of a major part of the isolates, highlighting the predominance of the S. saprophyticus species in the workshops studied. SIGNIFICANCE AND IMPACT OF THE STUDY: This tool is a useful way to screen the strains isolated from foodstuff and food environment and to monitor these species during the food processing.     

Analysis of Messenger RNA Coding for S100 Protein in the Mammalian Brain

S100 protein is a brain-specific protein which is absent at birth and first appears in rabbit brain 2–3 days after birth. To determine how the synthesis of this brain-specific protein is regulated, mRNA was isolated from brain polysomes and assayed for S100 protein mRNA activity by in vitro translation in a heterologous cell-free system and immunoprecipitation of released polypeptides with rabbit anti-S I00 protein antiserum. 5100 protein mRNA was detected primarily in small polysomes containing five to eight ribosomes, and virtually no S 100 protein mRNA was present in polysomes containing more than eight ribosomes. S100 protein mRNA was not detected in brain polysomes at stages prior to the induction of synthesis of S100 protein, i.e., in fetal brain or in 1-day neonates. The amount of S100 protein mRNA in polysomes of the cerebral cortex and cerebellum was measured to see if it correlated with the level of S100 protein in the two regions of adult brain. The cerebellum, which contained three to four times the level of S100 protein in the cerebral cortex, contained four times more S100 protein mRNA.     

薄鳞蕨属的分类研究

在野外考察和室内标本研究的基础上,对薄鳞蕨属（中国蕨科）的分类进行了研究。 将2种 (华西薄鳞蕨和察隅薄鳞蕨) 和2变种（大叶薄鳞蕨和宽叶薄鳞蕨）进行了归并处理, 承认该属有4种1变种。     

国产海桑属植物的两个杂交种

作者通过对红树林海桑属植物进行形态学、花粉学、细胞学以及其它方面的比较研究,证实了拟海桑和海南海桑为两个杂交种,它们的嫌疑亲本分别是杯萼海桑和海桑、杯萼海桑和卵叶海桑·ｓｏｎｎｅｒａｔｉａ×ｈａｉｎａｎｅｎｗｓｉｓｋｏ,ＥＹ．ＣｈｅｎｅｔＷ．Y　Ｃｈｅｎ（ｐｒｏｓｐ）为海南海桑的新名称,而拟海桑S．ｐａｒａｃｓｅｏｌａｒｉｓＫｏ,Ｅ.Ｙ.Ｃｈｅｎ,ｅｔＷ,ＣｈｅｎＹ.Ｃｈｅｎ则被归并入ｓｏｎｎｅｒａｔｉａ×ｇｕｌｎｇａｉＮ.C．Ｄｕｋｅ．     

Identification of the nucleotide sequences involved in the interaction between Escherichia coli 5 RNA and specific 50 S subunit proteins

Pancreatic RNase partial digests of ³²P-labelled 5 S RNA-protein complexes have been fractionated by electrophoresis on polyacrylamide gels. Specific fragments of the 5 S RNA molecule have been recovered from electrophoresis bands containing polynucleotide-protein complexes. These digestion-resistant complexes are only found if RNase treatment is carried out in the presence of at least one of the two 50 S subunit proteins L18 and L25, which are able to bind to 5 S RNA individually and specifically. The sequences of the isolated fragments have been determined. From the results, it can be concluded that sequence 69 to 120 and, possibly, sequence 1 to 11, are involved in the 5 S RNA-protein interactions which are responsible for the insertion of 5 S RNA in the 50 S subunit structure. Sequence 12 to 68, on the other hand, has no strong interactions with proteins L18 and L25. Each protein certainly binds to several nucleotide residues, which are not contiguous in the primary structure. In particular, good experimental evidence has been obtained in favour of the binding of protein L25 to two distant regions of the 5 S RNA molecule, which must have a bihelical secondary structure. The importance of the 5 S RNA conformation for its proper insertion in the 50 S subunit is thus confirmed.     

中国菝葜属补充与订正

本文涉及百合科菝葜属Smilax 7个分类群：用Smilax longibracteolata J.D.Hook.和S.elegans Wall.ex Kunth分别代替中国植物志第15卷(1978)中由于鉴定错误而使用的〖WTBX〗S.ma ireiH.Lévl.和S.glaucophylla Klotz.S.mairei是一个完全不同的种,应予承认,现根据存于爱丁堡的模式标本予以重新描述。S.pinfae nsis H.Lévl.和nthaC.H.Wright 在中国植物志第15卷中被分别并入S.cocculoides Warb.和S.ferox Wall.ex Kunth,现恢复为独立的种。此外,本文还发表了一个新改级〖WTBX〗S.retroflexa[WTBZ] (Wang et Tang ) S.C.Chen和一个新名称S.munita S.C.Chen,后者用来代替晚出同名S.rigida Wall.ex Kunth。     

Taxon delimitation and genetic similarities of the Sphagnum imbricatum complex,as revealed by enzyme electrophoresis

Abstract

Isozyme electrophoretic studies were used to assess genetic variation in the Sphagnum imbricatum complex in a sample of 1332 plants from 39 populations from western Europe, eastern North America and Japan. Mean pairwise genetic distance among populations clustered and depicted in a UPGMA phenogram correspond to the recognition of four species, viz. Sphagnum portoricense , S. affine , S. imbricatum and S. austinii. The mean pairwise genetic identity among conspecific populations were 0.976, 0.847 and 0.841 for S. austinii , S. affine and S. portoricense, respectively. The mean pairwise genetic identity among taxa was 0.525 (S. austinii–S. affine), 0.476 (S. affine –S. portoricense), 0.600 (S. affine–S. imbricatum), 0.484 (S. imbricatum–S. austinii), 0.629 (S. imbricatum –S. portoricense) and 0.285 (S. austinii–S. portoricense). Populations of S. austinii in Europe are found to be genetically eroded (Hs = 0.001 ± 0.000), (P₉₅ = 0.00), probably due to severe bottlenecks caused by a series of founder effects during postglacial migration from a limited number of glacial refugia in S.W. Europe. The mean genetic diversity of S. affine (Hs = 0.122 ± 0.020) is at the same level as up to now reported for the more variable congeneric species. Among individuals of S. affine, 0.27% displayed mixed markers, indicating that, on rare occasions, hybridization may occur between S. affine and S. austinii. Preliminary genetic analysis of S. steerei supports the recognition of this taxon.     

Evaluation of the contribution of D9S1120 to anthropological studies in Native American populations

The D9S1120 locus exhibits a population-specific allele of 9 repeats (9RA) in all Native American and two Siberian populations currently studied, but it is absent in other worldwide populations. Although this feature has been used in anthropological genetic studies, its impact on the evaluation of the structure and genetic relations among Native American populations has been scarcely assessed. Consequently, the aim of this study was to evaluate the anthropological impact of D9S1120 when it was added to STR population datasets in Mexican Native American groups. We analyzed D9S1120 by PCR and capillary electrophoresis (CE) in 1117 unrelated individuals from 13 native groups from the north and west of Mexico. Additional worldwide populations previously studied with D9S1120 and/or 15 autosomal STRs (Identifier kit) were included for interpopulation analyses. We report statistical results of forensic importance for D9S1120. On average, the modal alleles were the Native American-specific allele 9RA (0.3254) and 16 (0.3362). Genetic distances between Native American and worldwide populations were estimated. When D9S1120 was included in the 15 STR population dataset, we observed improvements for admixture estimation in Mestizo populations and for representing congruent genetic relationships in dendrograms. Analysis of molecular variance (AMOVA) based on D9S1120 confirms that most of the genetic variability in the Mexican population is attributable to their Native American backgrounds, and allows the detection of significant intercontinental differentiation attributed to the exclusive presence of 9RA in America. Our findings demonstrate the contribution of D9S1120 to a better understanding of the genetic relationships and structure among Mexican Native groups.     

Neutron-scattering studies of the ribosome of Escherichia coli: a provisional map of the locations of proteins S3, S4, S5, S7, S8 and S9 in the 30 S subunit.

Results of neutron-scattering experiments to determine the distances between seven pairs of proteins within the 30 S ribosomal subunit are presented. These results, combined with earlier data (Engelman et al., 1975; Moore et al., 1977) lead to the construction of a three-dimensional map of the positions of the centers of mass of proteins S3, S4, S5, S7, S8 and S9. The properties of this map and its relationship to other information on the structure of the 30 S subunit are discussed.     

Topography of rna in the ribosome localization of the 16 s rna 5' end by immune electron microscopy

The location of the 5′ end of 16 S RNA on the 30 S subunit has been determined. This has been done using immune electron microscopy of the 30 S subunits reconstituted from the 16 S RNA carrying 2,4-dinitrophenyl-hapten at its 5′-terminal phosphate group. Triphenylphosphine/2,2′-dipyridyl disulfide and 2,4-dinitrophenyl-ethylenediamine have been used as condensing and nucleophilic reagents, respectively, for modification of 16 S RNA. The reaction proceeds rapidly in mild conditions and results in a high yield of the modified RNA. Thus, a new general procedure for labeling the 5′-terminal nucleotides of high molecular weight RNAs is described. The 5′ end of 16 S RNA has been found to be located on a “lower” one-third of the small ribosomal subunit, on the side opposite to the ledge (platform).     

Binding of the rat liver 7-8 S dexamethasone receptor to deoxyribonucleic acid

The 7-8 S form of the [3H]dexamethasone (9 alpha-fluoro-11 beta,17,21-trihydroxy-16 alpha-methylpregna-1,4-diene-3, 20-dione) receptor from rat liver cytosol can be converted to the 3-4 S form by RNase treatment or high salt, suggesting a salt-sensitive association between the receptor protein and RNA. In DNA-cellulose column assays, the gradient-purified 3-4 S form bound DNA more efficiently than the 7-8 S form, though the 7-8 S form was also capable of binding to DNA-cellulose to a significant extent. Activated 7-8 S dexamethasone receptor could be released from its association with soluble DNA by treatment with DNase I. Sucrose gradient analysis showed that the released receptor sedimented as the 7-8 S form and was sensitive to RNase treatment, which induced a conversion to the 3-4 S form. Activated RNase-generated 3-4 S receptor again displayed a higher degree of binding to soluble DNA and was recovered in the 3-4 S form following DNase extraction. The fact that the 3-4 S form bound immobilized or soluble DNA more efficiently suggests that the associated RNA of the 7-8 S form interferes directly or indirectly with the receptor association with DNA. The observation that the receptor binds to DNA in its 7-8 S form suggests that the receptor complex is capable of binding RNA and DNA concurrently.     

Biochemical research on oogenesis. RNA accumulation during oogenesis of the dogfish Scyliorhinus caniculus

Four biochemical mechanisms have been shown to operate in the oocytes of amphibians and teleosts: (1) amplification of the 28 S and 18 S genes, (2) noncoordinate accumulation of 5 S RNA and 28 S + 18 S RNA, (3) storage of 5 S and transfer RNA made in excess by small oocytes within nucleoprotein particles, (4) expression of different 5 S genes in oocytes and somatic cells. We have tried to extend these observations to another group of vertebrates, i.e., selacians (Chondrichthya). Our data suggest that ribosomal gene amplification is low or absent in the oocytes of the dogfish Scyliorhinus caniculus. However, previtellogenic oocytes of this species accumulate more 5 S RNA than needed for ribosome assembly. Transfer and 5 S RNA present in small oocytes are probably not free in the cell sap. A substantial fraction of these RNAs sediments at 10 S when homogenates of immature ovaries are centrifuged in sucrose density gradients. In contrast to what we observed in amphibians and teleosts, 5 S RNA from ovaries of S. caniculus is identical in sequence to 5 S RNA from liver. Among the four mechanisms mentioned above, the second and probably the third one are used by the oocytes of S. caniculus. Mechanism (4) is absent in this species. No definitive conclusion can be drawn concerning mechanism (1), i.e., ribosomal gene amplification.     

Three New Species of Brevitobrilus (Nematoda) with a Discussion on Relationships within the Genus

Three new species of the genus BrevitobriusTsalolikhin, 1981 are described. Brevitobrilus glandulatus n. sp. is characterized by conspicuous sphincter between pars dilatata and uterus; two pairs of vaginal glands; spicules having elliptical capitula with small proximal stiffening piece; proximally-arcuate gubernaculum; S3 and S4 smaller than other supplements; S6 out of spicular range and 57-60 micropapillae. Brevitobrilus dimorphicus n. sp. is diagnosed by sexual dimorphism in labial sensilla and amphids; thick-walled rectum with a diverticulum protruding into intestinal lumen and males with boat-shaped spicules and S6 occasionally slightly smaller than other supplements. Brevitobrilus allahabadensis n. sp. possesses large amphids of 28-33% of corresponding labial diameter in both sexes; vagina and uterus with muscular, plicate walls; well developed sphincter between vas deferens and ejaculatory duct; capitulate spicules with sloping ventral and angular dorsal walls; S3, S4 and S6 smaller than other supplements, S6 close to cloaca and 28-37 micropapillae. The relationships of the species of genus Brevitobrilus have been assessed using morphological characters subjected to parsimony and a non cladistic key to identification of species is given.     

The evolution of Spartina anglica G. E. Hubbard (Gramineae): genetic variation and status of the parental species in Britain

The perennial salt marsh grass Spartina anglica is one of the classic examples of allopolyploid speciation. It originated on the south coast of England at the end of the nineteenth century following chromosome doubling in S. × townsmdii , a hybrid between the native British S. marilima and a species introduced from the United States, S. alterniflora. The nature of the origin of S. anglica is beyond doubt; however, it is not known whether it had a single or multiple origin. In order to address this problem we undertook a survey of the genetic variation in the parental species of S. anglica using isozyme electrophoresis. The results show that S. alterniflora has no detectable variation and that S. maritima has extremely low levels of variation. These results, unfortunately, prevent the question of a single or multiple origin from being answered. Possible reasons for the low levels of variation and its influence on the future of the species are discussed. Another problem concerning the parental species is the rapid decline of S. maritima in Britain. It is often assumed that the major factor in this regression is the invasion of its habitats by S. anglica. We have examined the status of S. marilima throughout its range in Britain and have found that S. anglica rarely co-occurs with S. maritima. We propose that the decline of S. maritima is largely due to the physical erosion of its habitats and that this erosion may produce suitable habitats for colonization by S. anglica.     

The Precautionary Preference: An American Perspective on the Precautionary Principle

The precautionary principle, a familiar constituent of international and European environmental law, has only very recently entered the vocabulary of domestic environmental policy debates in the United States. The question naturally arises what role such a principle should play in American law. By breaking down statements of the precautionary principle into distinct ele ments, one can more readily find ways in which U.S. law reflects the precau tionary principle. This analysis reveals that American environmental law con tains precautionary elements and goals in many and varied settings, from the management of natural ecosystems, to pollution control standards, to risk assessment methodology. However, the precautionary approach appears in a highly diluted or compromised form. With rare exceptions, U.S. law balances precaution against other considerations, most importantly cost. Therefore, while precautionary elements are firmly entrenched in U.S. environmental law, it is more accurate to say that it reflects a precautionary preference rather than the precautionary principle.     

The effect of particle characteristics on the beam attenuation coefficient and output from an optical backscatter sensor

Experiments were conducted to measure optical backscatter and beam transmission of suspensions of 180, 150 and 90 μm sand, and 40 μm clay, in a recirculation tank designed to house an optical backscatterance sensor (O.B.S.) and a beam transmissometer. Particle size was determined using gravimetric techniques and Coulter counter. By contriving known sediment distributions from the fractionated sediment samples, it was found that both the O.B.S. and beam transmissometer responded approximately linearly to narrow band and broad band particle suspensions. The beam transmissometer showed greater sensitivity to the fine-grain fraction of a poly-disperse suspension than the O.B.S.     

Biochemical research on oogenesis. Comparison between the proteins of the ribosomes and the proteins of the 42 S particles from small oocytes of Xenopus laevis

Previtellogenic oocytes of Xenopus laevis synthesize large amounts of 5 S RNA and transfer RNA, but very little, if any, 28 S and 18 S RNA. About half of the RNA of these oocytes is stored in nucleoprotein particles sedimenting at 42 S. These particles contain 5 S RNA, transfer RNA, and several proteins, the function of which remains so far unknown.The proteins of the 42 S particles were analyzed by two-dimensional electrophoresis on polyacrylamide gel. The resulting fingerprints displayed one major and two minor basic spots. None of these coincided with any of the 37 spots produced by the 60 S subunit of the ribosomes and with the 30 spots produced by the 40 S subunit. We conclude that no ribosomal component other than 5 S RNA is present in the 42 S particles.The fingerprints of 40 S and 60 S ribosomal proteins from X. laevis coincided almost completely with the corresponding fingerprints from the rat and the rabbit.     

The longer you stay, the bigger you get: length of time and language use in the U.S. are associated with obesity in Puerto Rican women

This cross-sectional study examined whether length of time in the U.S., language use, and birthplace (proxy measures of acculturation) were associated with body mass index (BMI) and obesity in a sample of 174 low-income Puerto Rican women from Hartford, Connecticut. The mean BMI for the total sample (N = 174) was 27.39 (S.D. = 5.07), and nearly 34% of the sample was considered obese (BMI > or = 30). There was a statistically significant increase in BMI with length of time in the U.S. (P = 0.012) and these differences were even greater among women born in Puerto Rico (P = 0.003). Moreover, obesity prevalence was highest among women who had been in the U.S. for 10 years or more (40%), as compared to those who had been in the U.S. less than 1 year (29%; P = 0.045). There were no statistically significant associations between language and BMI for the total sample. However, among bilingual speakers born in Puerto Rico, there were significant differences in BMI according to their level of English fluency. Those who spoke fluent or very good English had a significantly higher BMI (mean = 29.72; SD = 4.12) than women whose English was good to not-so-good (mean = 26.8; SD = 5.24; P = 0.016). The findings from this study point to the need for more research on the acculturation process and obesity, in order to design culturally tailored obesity prevention programs.     

SEF14菌毛基因操纵子在肠炎沙门氏菌和D-群沙门氏菌的变异分析

【目的】本文旨在探索SEF14菌毛特异性表达于D-群沙门氏菌,特别是肠炎沙门氏菌以及都柏林沙门氏菌的原因。【方法】应用PCR扩增以及序列测定检测了18株鸡白痢沙门氏菌,11株肠炎沙门氏菌以及1株都柏林沙门氏菌标准株中sefA,sefD和sefR基因序列,并分析比对其序列变异。【结果】以11株肠炎沙门氏菌以及1株都柏林沙门氏菌染色体DNA为模板能成功扩增sefA,sefD以及sefR基因;从18株鸡白痢沙门氏菌中均能成功扩增sefA基因,但只有分离于1980年之前的7株分离菌能成功扩增sefD和sefR基因,而另11株1980年后分离菌PCR扩增sefD和sefR基因却无任何产物。比对PCR扩增产物测序结果发现,11株肠炎沙门氏菌以及1株都柏林沙门氏菌株中sefA,sefD以及sefR基因序列和已发表的序列(GenBank登录号为L11008,U07129和AF233854)100%同源;7株鸡白痢沙门氏菌sefD基因测序结果表明,在196位点处发生碱基缺失,造成移码突变,提前于氨基酸残基71位点处产生终止密码子。优化菌毛表达条件,体外抽提和纯化菌毛并进一步试验证明:肠炎沙门氏菌以及都柏林沙门氏菌体外能很好表达SEF14菌毛,但鸡白痢沙门氏菌在相同培养条件下却无任何表达迹象。【结论】SEF14菌毛操纵子亚单位基因sefA,sefD以及调节基因sefR在不同沙门氏菌中的变异情况可能是SEF14菌毛局限性表达的原因之一。