Fibrivirga algicola gen. nov., sp. nov., an algicidal bacterium isolated from a freshwater river

An aerobic, gram-stain-negative, pink-colored, non-motile and rod-shaped algicidal bacterium, designated as JA-25^T was isolated from freshwater in Geumgang River, Republic of Korea. Strain JA-25^T grew at 15–30 °C and pH 6–9, and did not require NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain JA-25^T belongs to the family ‘Spirosomaceae’ and is most closely related to Fibrella aestuarina BUZ 2^T (93.6%). Strain JA-25^T showed?<?90% sequence similarity to other members of the family ‘Spirosomaceae’. The average nucleotide identity(ANI), in silico DNA-DNA hybridization and average amino acid identity(AAI) values based on the genomic sequences of JA-25^T and F. aestuarina BUZ 2^T were 74.4, 20.5, and 73.6%, respectively. Strain JA-25^T showed an algicidal effect on the marine flagellate alga Heterocapsa triquetra, but no effect on fresh water cyanobacterium (Nostoc). In genome analysis, RIPP-like peptides were detected and predicted to resemble the indolmycin biosynthetic gene cluster, which possibly influence its algicidal effect. Furthermore, a bacteriorhodopsin gene with photoheterotrophic characteristics was detected. The genomic DNA G?+?C content was 52.5 mol%. The major cellular fatty acids were summed feature 3 (C16:1 ω6c/C16:1 ω7c), C16:1 ω5c, C16:0 (>?10%). The major respiratory quinone was menaquinone 7 and major polar lipids were phosphatidylethanolamine, two unidentified aminolipids, two phospholipids, and five unidentified lipids. Considering the phylogenetic inference, phenotypic, and chemotaxonomic data, strain JA-25^T should be classified as a novel species in the novel genus Fibrivirga, with the proposed name Fibrivirga algicola sp. nov. The type strain is JA-25^T (=?KCCM 43334^T?=?NBRC 114259^T).

     

Characterization of recombinant rabies virus carrying double glycoprotein genes

A recombinant rabies virus carrying double glycoprotein (G) genes, R(NPMGGL) strain, was generated by a reverse genetics system utilizing cloned cDNA of the RC-HL strain, and the biological properties of the virus were compared to those of the recombinant RC-HL (rRC-HL) strain. The extents of virus growth in cultured cells and virulence for adult mice of the R(NPMGGL) strain were almost same as those of the rRC-HL strain, while G protein content of the purified R(NPMGGL) virion and G protein expression level in R(NPMGGL)-infected cells were 1.5-fold higher than those of the rRC-HL strain. As a result of serial passages of the R(NPMGGL) strain in cultured cells, the expression level of G protein in cultured cells infected with the passaged R(NPMGGL) strain was maintained and virus titers rose with adaptation to the cultured cells. Furthermore, analysis of neutralization titers in mice immunized with UVinactivated virus suggested that the R(NPMGGL) strain had higher immunogenicity than that of the rRC-HL strain. The results suggest that the R(NPMGGL) strain carrying double G genes might be a useful candidate for development of a new inactivated rabies vaccine.     

Lipoolygosaccharide indirectly enhances inflammatory lesions in lungs as a primary infection site by non-encapsulated and type B Haemophilus influenzae through production of cytokines

We investigated the role of cytokines in differences in histopathologic changes in the lung between bronchopneumonia caused by non-encapsulated Haemophilus influenzae strain 770235f(0)b(0)and systemic disease caused by type b H. influenzae strain 770235f(0)b(+). Tumour necrosis factor-alpha (TNF-alpha), interleukin-(IL)-6 and IL-1 beta levels in bronchoalveolar lavage fluid (BALF) samples of mice infected with strain 770235f(0)b(0)were higher than in those infected with strain 770235f(0)b(+)until 24 h post-infection. Serum IL-6 rapidly increased in strain 770235f(0)b(0)infection after 72 h post-infection. Serum TNF-alpha level in strain 770235f(0)b(0)infection appeared earlier than in strain 770235f(0)b(+)infection. IL-1 beta production in strain 770235f(0)b(+)infection was later than in strain 770235f(0)b(0)infection. Moreover, a biphasic concentration pattern of TNF-alpha and IL-6 was noted in BALF of mice with strain 770235f(0)b(0)infection.     

Saccharopolyspora pathumthaniensis sp. nov., a novel actinomycetes isolated from termite guts (Speculitermes sp.)

Morphological and chemotaxonomic characterization of actinomycete strain S582 isolated from the gut of a termite (Speculitermes sp.) in Pathum Thani Province, Thailand, clearly demonstrated that this strain is a member of the genus Saccharopolyspora. 16S rDNA sequence analysis for the strain supported the assignment of the strain to the genus Saccharopolyspora. The similarity value of sequences between this strain and the closely related species Saccharopolyspora endophytica was 99.5%. The DNA G+C content was 70.2 mol%. DNA-DNA hybridization results (53.3%) and some physiological and biochemical properties indicated that strain S582(T) was distinguished from the phylogenetically closest relatives. Based on these genotypic and phenotypic data, strain S582(T) should be a new species in the genus Saccharopolyspora and the name Saccharopolyspora pathumthaniensis sp. nov. is proposed for the strain. The type strain is S582(T) (=NBRC 104112(T) =BCC 28624(T)).     

Properties of Thymineless Strains of Bacillus megaterium

Both Bacillus megaterium KM:T(-)R(1), a strain partially resistant to thymineless death, and strain KM:T(-), the parent strain, can satisfy their thymine requirement with either thymidine, 5-methyldeoxycytidine, or 5-methyluridine. Neither strain can use 5-methylcytosine, 5-hydroxymethylcytosine, 5-hydroxymethyluracil, or 5-aminouracil for this purpose. Strain KM:T(-)R(1) requires as little as 0.01 mM thymine for maximum growth, whereas strain KM:T(-) requires 0.10 to 0.20 mM thymine. Lysogenic KM:T(-)R(1) dies more rapidly in the presence of mitomycin C than the corresponding phage-sensitive strain. Unexpectedly, the lysogenic strain was found to be less sensitive to thymineless death than the phage-sensitive strain. Lysogenic KM:T(-)R(1) is induced by exposure to mitomycin C and by thymineless incubation. It is concluded that thymineless death occurs by a mechanism which is unrelated to phage induction and that a major lethal effect of mitomycin C is probably a consequence of phage induction.     

Metabolism of thymineless mutants of Escherichia coli. I. Absence of thymidylate synthetase activity and growth characteristics of two sequential thymineless mutants

A study of optimal thymine and deoxythymidine (dThd) growth requirements of the thymineless mutants of Escherichia coli 15, E. coli 70-462 (strain 70), and a variant, E. coli 70V3-462 (strain 70V3), showed that for maximal turbidity (growth) strain 70 required 10-fold greater concentrations of thymine or dThd than did strain 70V3. On suboptimal concentrations of thymine or dThd, growth of strain 70 was greater on dThd than on thymine. In contrast, maximal growth of strain 70V3 was the same on equimolar concentrations of thymine and dThd. Growth rate of strain 70V3 was the same on equimolar concentrations of thymine and dThd up to 4 mum; at concentrations of 5 mum and greater, the "4-hr" growth was lower on dThd than on corresponding concentrations of thymine. Cultures of both thymineless mutants synthesized equal maximal amounts of DNA. Whereas strain 70V3 incorporated a maximum of 90% of the thymine or dThd in the media, strain 70 incorporated a maximum of only 10%. This poor utilization by strain 70 was neither a result of thymine or dThd conversion to a low-molecular-weight thymine derivative nor the production of a nonthymine inhibitory substance. Since strains 70 and 70V3 exhibited no thymidylate synthetase activity, the first mutation (strain 15 to strain 70) resulted in the loss of this activity. The second mutation (strain 70 to strain 70V3) probably brought about the loss of an enzyme(s) that catabolizes deoxyribose phosphate, permitting a greater net synthesis of dThd from thymine.     

Mechanical properties of trabecular bone. Dependency on strain rate.

The effect of strain rate (epsilon) and apparent density (rho) on stiffness (E), strength (sigma u), and ultimate strain (epsilon u) was studied in 60 human trabecular bone specimens from the proximal tibia. Testing was performed by uniaxial compression to 5% specimen strain. Six different strain rates were used: 0.0001, 0.001, 0.01, 0.1, 1, and 10 s-1. Apparent density ranged between 0.23 and 0.59 g cm-3. Linear and non-linear regression analyses using strength, stiffness and ultimate strain as dependent variables (Y) and strain rate and apparent density as independent variables were performed using the following models: Y = a rho b epsilon c, Y = rho b(a + c epsilon; Y = (a + b rho)epsilon c, Y = a rho 2 epsilon c, E = a rho 3 epsilon c. The variations of strength and stiffness were explained equally well by the linear and the power function relationship to strain rate. The exponent was 0.07 in the power function relationship between strength and strain rate and 0.05 between stiffness and strain rate. The variation of ultimate strain was explained best using a power function relationship to strain rate (exponent = 0.03). The variation of strength and stiffness was explained equally well by the linear, power function and quadratic relationship to apparent density. The cubic relationship between stiffness and apparent density showed a less good fit. Ultimate strain varied independently of apparent density.     

Strain and strain rate activation of G proteins in human endothelial cells

The endothelium is known to sense and respond to its physical environment, but the underlying mechanisms and early events of endothelial cell mechanotransduction are not well understood. The present study measured G protein activation by mechanical strain in human umbilical vein endothelial cells (HUVEC) directly by photoincorporation of a hydrolysis resistant, radiolabeled GTP analog. Ten percent uniaxial strain at a strain rate of 20% s(-1) over 1min activated a 38kDa Galpha subunit 167+/-17% relative to controls, while 2% cyclic strain failed to significantly activate the protein (117+/-19%). A single cycle of 10% strain at 20% s(-1) strain rate activated the Galpha subunit 152+/-25%, while activation at the same strain but lower strain rate (0.3% s(-1)) was not significantly different from controls (116+/-12%). Western blot analysis identified the 38kDa protein as Galpha(q/11). These results demonstrate the rapid activation of G proteins in HUVEC by cyclic uniaxial strain in a strain- and strain rate-dependent manner.     

Isoenzymatic pattern of Trypanosoma cruzi Y strain after specific chemotherapy

The isoenzyme pattern of the Trypanosoma cruzi Y strain recovered from mice inoculated with 15 x 10(4) blood trypomastigotes and previously treated with either Bay 2502 (Nifurtimox) or Ro 7-1051 (Benzonidazol) was analyzed in the following situations: a) strain resistant to Bay 2502 and again treated with the same drug; b) strain resistant to Bay 2502 and treated with Ro 7-1051; c) strain resistant to Ro 7-1051 and treated with that same drug. Although marked drug resistance was noted in all cases, the isoenzyme pattern of the Y strain for GPI, PGM, ALAT and ASAT remained throughout the same. The pattern was similar to that of the Peruvian strain, which also belongs to the same strain Type of the Y strain, but differed from those of the 21 SF (Type II) and Colombian (Type III) strains. Thus, the appearance of drug resistance in T. cruzi strain was not associated with a change in its isoenzymatic pattern.     

The relative value of strain and strain rate for defining intrinsic myocardial function

It is well accepted that strain and strain rate deformation parameters are not only a measure of intrinsic myocardial contractility but are also influenced by changes in cardiac load and structure. To date, no information is available on the relative importance of these confounders. This study was designed to investigate how strain and strain rate, measured by Doppler echocardiography, relate to the individual factors that determine cardiac performance. Echocardiographic and conductance measurements were simultaneously performed in mice in which individual determinants of cardiac performance were mechanically and/or pharmacologically modulated. A multivariable analysis was performed with radial and circumferential strains and peak systolic radial and circumferential strain rates as dependent parameters and preload recruitable stroke work (PRSW), arterial elastance (E(a)), end-diastolic pressure, and left ventricular myocardial volume (LVMV) as independent factors representing myocardial contractility, afterload, preload, and myocardial volume, respectively. Radial strain was most influenced by E(a) (β = -0.58, R(2) = 0.34), whereas circumferential strain was strongly associated with E(a) and moderately with LVMV (β = 0.79 and -0.52, respectively, R(2) = 0.54). Radial strain rate was related to both PRSW and LVMV (β = 0.79 and -0.62, respectively, R(2) = 0.50), whereas circumferential strain rate showed a prominent correlation only with PRSW (β = -0.61, R(2) = 0.51). In conclusion, strain (both radial and circumferential) is not a good surrogate measure of intrinsic myocardial contractility unless the strong confounding influence of afterload is considered. Strain rate is a more robust measure of contractility that is less influenced by changes in cardiac load and structure. Thus, peak systolic strain rate is the more relevant parameter to assess myocardial contractile function noninvasively.     

Interrelationships in trace-element metabolism in metal toxicities in a cobalt-resistant strain of Neurospora crassa

A strain of Neurospora crassa was isolated by training the mould to grow on media containing high concentrations of Co(2+). This strain, the Co(R) strain, exhibited approximately tenfold the resistance of the parent strain to Co(2+) and Ni(2+) but not to Zn(2+) or Cu(2+). Co(2+) toxicity in the Co(R) strain was reversed by Mg(2+) but not by Fe(3+). Also, Co(2+) did not affect iron metabolism in this strain. It is suggested that the mechanism of resistance in the Co(R) strain involves an alteration in the pattern of iron metabolism such that the latter is no longer adversely affected by toxic concentrations of Co(2+). The Co(R) strain is genetically stable and is most probably a result of a resistance mutation in N. crassa induced by Co(2+).     

Immunization of pigs with the attenuated S- strain of Japanese encephalitis virus.

The attenuated S- strain of Japanese encephalitis virus was produced from a wild strain of this virus by serial cultivation in primary bovine kidney cell cultures at 30 degrees C. Pigs were inoculated with it and examined for ability to produce antibody and protect themselves from infection with a wild strain used for challenge. In pigs inoculated with a single dose of 10(6.5) approximately 10(7.5) TCID50 of the S- strain, the neutralizing antibody titer or hemagglutination-inhibiting antibody (HI) titer increased to 10 approximately 320. An antibody titer exceeding 10 was maintained for 2 approximately 9 weeks. In pigs inoculated twice with 10(6.5) approximately 10(7.0) TCID50 of the S- strain, HI titer increased to 80 approximately 640. In many of these pigs, HI titers of 80 approximately 160 persisted for more than 6 weeks. Pigs inoculated once or twice with 10(7.0) approximately 10(7.5) TCID50 of the S- strain were challenged by inoculation with 10(4.5) approximately 10(5.5) TCID50 of a wild strain and examined for the occurrence of viremia. As a result, an ability to protect from infection was demonstrated in pigs which showed an antibody titer surpassing 10 at the time of challenge. Pregnant sows inoculated with 10(7.0) TCID50 of the S- strain were challenged by inoculation with 10(7.0) TCID50 of a wild strain. Neither death nor infection occurred to any fetus harbored by them. From these results, it is concluded that the S- strain can be used as live virus vaccine for porcine practice.     

食用营养酵母菌种的选育

通过对面包酵母、假丝酵母、啤酒酵母和奶酒酵母等四种酵母的核黄素、自溶浸出物比率进行研究,选定了核黄素及自溶浸出物比率较高的奶酒酵母(MY-1)作为出发菌株。经连续3次EMS诱变,依次选育富含核黄素的腺嘌呤营养缺陷型菌株(Ml-3)和腺嘌呤缺陷型的回复突变株(M2-8)。对所得的菌株进一步进行抗铵突变株的选育,最终得到富含核黄素的营养酵母突变株(M3-20),其核黄素含量与出发菌株相比提高了约215％。     

Isolation and characterization of recombinants between attenuated and virulent aphthovirus strains.

A guanidine-resistant mutant of the attenuated strain of aphthovirus type 01 strain Campos and the original wild-type strain were crossed to generate recombinant viruses. Two independently derived recombinant viruses were isolated. One isolate (RI) contained the P1 (structural proteins) gene region of attenuated strain and P3 (polymerase precursor) gene region of the wild-type strain. The other isolate (RII) had a genomic structure complementary to that of RI, this is, P1 of the wild-type strain and P3 of the attenuated virus. Recombinant RII inherited some in vitro phenotypic markers that were characteristic of the attenuated strain, whereas the RI recombinant had in vitro behavior that was similar to that of the wild-type strain. The data obtained suggest that the polymerase precursor (P3) of the attenuated strain (01 Campos) could be involved in the determination of the attenuated phenotype for fetal bovine kidney cells and, eventually, for cattle.     

Inheritance of photo-control of conidial development in the fungusBipolaris oryzae

The inheritance of light dependence for conidial development inBipolaris oryzae was analyzed using single-ascospore isolates. When a photo-induced strain was crossed with another photo-induced strain, only photo-induced progeny were produced. When a photo-induced strain was crossed with a non-photo-induced (I) strain, photo-induced and nonphoto-induced (I) progeny were produced in a ratio of 1∶1. However, when a photo-induced strain was crossed with a non-photo-induced (II) strain, a non-photo-induced (I) progeny were formed in addition to parental types. It was suggested that genes for photo-control of conidiophore induction and genes for photo-control of conidiophore maturation are located on the same chromosome.     

The effect of strain rate on the mechanical properties of human cortical bone

Bone mechanical properties are typically evaluated at relatively low strain rates. However, the strain rate related to traumatic failure is likely to be orders of magnitude higher and this higher strain rate is likely to affect the mechanical properties. Previous work reporting on the effect of strain rate on the mechanical properties of bone predominantly used nonhuman bone. In the work reported here, the effect of strain rate on the tensile and compressive properties of human bone was investigated. Human femoral cortical bone was tested longitudinally at strain rates ranging between 0.14-29.1 s(-1) in compression and 0.08-17 s(-1) in tension. Young's modulus generally increased, across this strain rate range, for both tension and compression. Strength and strain (at maximum load) increased slightly in compression and decreased (for strain rates beyond 1 s(-1)) in tension. Stress and strain at yield decreased (for strain rates beyond 1 s(-1)) for both tension and compression. In general, there seemed to be a relatively simple linear relationship between yield properties and strain rate, but the relationships between postyield properties and strain rate were more complicated and indicated that strain rate has a stronger effect on postyield deformation than on initiation of yielding. The behavior seen in compression is broadly in agreement with past literature, while the behavior observed in tension may be explained by a ductile to brittle transition of bone at moderate to high strain rates.     

猪细小病毒SD-68株vp2基因的克隆及序列分析

对猪细小病毒(PPV)SD-68株印2基因进行的克隆和序列测定表明：SD-68株VP2基因全长1740bD,编码579个氨基酸残基组成的多肽;PPVSD-68株与Kresse株、SY-99株、NADL-2(5075)株、NADL-2(4973)株、US-1株的VP2基因比较,核苷酸的同源性在99％以上,氨基酸的同源性在96％以上。进化树分析表明SD-68株与kresse株的亲缘关系最近;在决定毒株组织嗜性的关键氨基酸位点上(378,383及436),SD-68株与kresse株的差异最小,据此推测SD-68株的组织嗜性与Kresse株相似,即SD-68株属皮炎型PPV;而比较弱毒株NADL-2、SD-68和强毒株kresse VP2的氨基酸差异后发现,215、378和383可能是决定PPV致病性强弱的关键位点。     

Adaptation and selection of prion protein strain conformations following interspecies transmission of transmissible mink encephalopathy

Interspecies transmission of the transmissible spongiform encephalopathies (TSEs), or prion diseases, can result in the adaptation and selection of TSE strains with an expanded host range and increased virulence such as in the case of bovine spongiform encephalopathy and variant Creutzfeldt-Jakob disease. To investigate TSE strain adaptation, we serially passaged a biological clone of transmissible mink encephalopathy (TME) into Syrian golden hamsters and examined the selection of distinct strain phenotypes and conformations of the disease-specific isoform of the prion protein (PrP(Sc)). The long-incubation-period drowsy (DY) TME strain was the predominate strain, based on the presence of its strain-specific PrP(Sc) following interspecies passage. Additional serial passages in hamsters resulted in the selection of the hyper (HY) TME PrP(Sc) strain-dependent conformation and its short incubation period phenotype unless the passages were performed with a low-dose inoculum (e.g., 10(-5) dilution), in which case the DY TME clinical phenotype continued to predominate. For both TME strains, the PrP(Sc) strain pattern preceded stabilization of the TME strain phenotype. These findings demonstrate that interspecies transmission of a single cloned TSE strain resulted in adaptation of at least two strain-associated PrP(Sc) conformations that underwent selection until one type of PrP(Sc) conformation and strain phenotype became predominant. To examine TME strain selection in the absence of host adaptation, hamsters were coinfected with hamster-adapted HY and DY TME. DY TME was able to interfere with the selection of the short-incubation HY TME phenotype. Coinfection could result in the DY TME phenotype and PrP(Sc) conformation on first passage, but on subsequent passages, the disease pattern converted to HY TME. These findings indicate that during TSE strain adaptation, there is selection of a strain-specific PrP(Sc) conformation that can determine the TSE strain phenotype.     

Biodegradation of bisphenol A and related compounds by Sphingomonas sp. strain BP-7 isolated from seawater

A bacterium capable of assimilating 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), strain BP-7, was isolated from offshore seawater samples on a medium containing bisphenol A as sole source of carbon and energy, and identified as Sphingomonas sp. strain BP-7. Other strains, Pseudomonas sp. strain BP-14, Pseudomonas sp. strain BP-15, and strain no. 24A, were also isolated from bisphenol A-enrichment culture of the seawater. These strains did not degrade bisphenol A, but accelerated the degradation of bisphenol A by Sphingomonas sp. strain BP-7. A mixed culture of Sphingomonas sp. strain BP-7 and Pseudomonas sp. strain BP-14 showed complete degradation of 100 ppm bisphenol A within 7 d in SSB-YE medium, while Sphingomonas sp. strain BP-7 alone took about 40 d for complete consumption of bisphenol A accompanied by accumulation of 4-hydroxyacetophenone. On a nutritional supplementary medium, Sphingomonas sp. strain BP-7 completely degraded bisphenol A and 4-hydroxyacetophenone within 20 h. The strain degraded a variety of bisphenols, such as 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, and 1,1-bis(4-hydroxyphenyl)cyclohexane, and hydroxy aromatic compounds such as 4-hydroxyacetophenone, 4-hydroxybenzoic acid, catechol, protocatechuic acid, and hydroquinone. The strain did not degrade bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)sulfone, or bis(4-hydroxyphenyl)sulfide.     

Mycoplasma simbae sp. nov., Mycoplasma leopharyngis sp. nov., and Mycoplasma leocaptivus sp. nov., isolated from lions.

Mycoplasmas isolated from the throats of lions were shown to belong to three serotypes, all of which were serologically distinct from the previously recognized Mycoplasma and Acholeplasma spp. Eight mycoplasma colonies were cloned, including one from a leopard (strain LP), and were examined in detail for morphology, growth, and biochemical characteristics. The strains had the following properties: guanine-plus-cytosine contents of 37 mol% (strain LXT [T = type strain]), 28 mol% (strain LL2T), and 27 mol% (strain 3L2T) and a requirement for sterol. Strain 3L2T metabolized glucose, which was not metabolized by strains LXT and LL2T. Arginine and urea were not hydrolyzed. Strain LX (= NCTC 11724) is the type strain of a new species, Mycoplasma simbae; strain LL2 (= NCTC 11725) is the type strain of a second new species, Mycoplasma leopharyngis; and strain 3L2 (= NCTC 11726) is the type strain of a third new species, Mycoplasma leocaptivus.