共查询到20条相似文献,搜索用时 15 毫秒
1.
Fumio Oosawa 《Biopolymers》1968,6(1):135-144
A theoretical analysis is given on the effect of low molecular salts on the titration behavior of partially neutralized linear polyacids or polybases. On the basis of the additivity law experimentally and theoretically established on the activity of counterions in polyelectrolyte solutions containing salts, the chemical potential of alkali added for neutralization of polyacids is derived as a function of the salt concentration. The relation between the pH and the salt, concentration at constant degree of neutralization is expressed by pH(cs) ? pH(0) = ({[? (γpCa)/?Ca]/γos} ? 1) ln [1 + (γosCs/γpCA)] where Ca is the concentration of alkali, C8, the concentration of salts, γp is the activity coefficient of counterions in the absence of salts and γos is that in the absence of polyelectrolytes. This relation is found to be in good agreement with experimental data obtained in synthetic linear polyelectrolytes as well as in rodlike charged proteins. Therefore, it is concluded that the titration behavior of linear polyions can be understood from the special feature of the integrated coulomb interaction between linear polyions and small ions which was essential for the additivity law. In addition, the screening effect of salts on the electric potential around the polyion is discussed. 相似文献
2.
G. A. Kovalenko N. B. Shitova V. D. Sokolovskii 《Biotechnology and bioengineering》1981,23(8):1721-1734
Lactate dehydrogenase (LDH) was adsorbed on low-(γ, η) and high -(θ, α) temperature forms of alumina. θ-Al2O3 exhibited the greatest adsorption ability. The maximum adsorption value was 30 mg LDH/g of a carrier. The conditions for irreversible adsorption have been determined. An adsorption isotherm on θ-Al2O3 for pH 6.0 has been obtained; the LDHads surface area and the carrier surface portion accessible to the enzyme molecules have been calculated. The reaction kinetic parameter were determined by taking into account the reaction proceeding in the intradiffusional region. The specific catalytic activity (Aspec) of LDHads at small surface coverage of θ-Al2O3 is five times less than Aspec of the native enzyme and KMimm with respect to NADH exceeds KMnat by two orders or magnitude. The is evidence for a strong LDH–Al2O3 interaction and a considerable deformation of the enzyme globule. Aspec and KM decrease as the amount of the enzyme attached to the carrier increases. Due to adsorption. LDH becomes thermostable and durable. The LDHads samples conserve 20–40% of their activity at room temperature during a year. 相似文献
3.
Effect of Anabaena flos-aquae on the abilities of Daphnia and Keratella to feed and reproduce on unicellular algae 总被引:1,自引:0,他引:1
SUMMARY.
- 1 This study tests the hypothesis that the filamentous cyanobacterium, Anabaena flos-aquae, inhibits Daphnia's ability to feed and reproduce on unicellular algae more than it does Keratella's. Double-label radiotracer experiments using whole and sonieally disrupted Anabaena filaments showed that even low concentrations of Anabaena (5 × 103 cells ml?1) inhibited the abilities of Daphnia pulex and D. galeata mendotae to feed on Chlamydomonas and that this inhibition was due to both mechanical interference with feeding and increased food availability. A single-label radiotracer experiment showed that Anabaena (5 × 103 and 2 × 104 cells ml?l) reduced the abilities of neonate, juvenile, and adult D. pulex to feed on Chlamydomonas but had a much more pronounced effect on adults.
- 2 Single-label radiotracer experiments using screened (25 μm mesh) and unscreened suspensions of whole Anabaena filaments showed that only very high concentrations of Anabaena (105 cells ml?1) reduced the ability of Keratella cochlearis to feed on Cryptomonas and that this inhibition probably was due to mechanical interference with feeding, since Keratella ate Anabaena extremely inefficiently - especially when single cells and short filaments were removed by screening.
- 3 Experiments comparing the survivorship and fecundity of individuals fed Anabaena, Chlamydomonas, or no food showed that the Anabaena was not toxic to either Keratella or D. galeata mendotae, was not utilized by Keratella, and was utilized by Daphnia, although not as well as Chlamydomonas was.
- 4 Anabaena (5 × 103 or 104 cells ml?1) did not affect, or slightly increased, the population growth rate (rm) of K. cochlearis on Cryptomonas, while it substantially increased that of D. pulex, Duphnia's ability to utilize Anabaena probably more than offset its reduced ability to feed on Cryptomonas. The presence of cyanobacterial filaments in natural plankton communities could adversely affect Daphnia and decrease its ability to competitively suppress Keratella and other rotifers if the filaments were of little nutritional value to the Daphnia, greatly interfered
4.
We show that the persistence length a of DNA, derived from total intensity laser light scattering of linear Col E1 DNA and corrected for excluded-volume effects, varies from about 68 nm in 0.005M NaCl to about 40 nm in 0.2M NaCl, leveling off to a constant value (about 27 nm) at high NaCl (1–4M) concentration. These observations do not agree with current views on the effect of electrostatic charge and ionic conditions on DNA dimensions. The apparent diffusion constant Dapp, determined from laser light scattering autocorrelation as a function of scattering vector q, at NaCl concentrations 0.005–4M, correctly yields the translational diffusion coefficient Dt at low values of q and scales with molecular dimensions rather than segment length at high values of q; thus, Dapp/Dt yields a universal curve when plotted against q2R, where Rg is the radius of the gyration. The sedimentation coefficients s at 0.1 and 0.2M NaCl concentration closely agree with the well-tested empirical relations, and a combination of s, Dt, and the appropriate density increments yield correct molar masses over the whole salt concentration range. Approximate constancy of DtRg indicates limited draining in translational flow. We present some observations and thoughts on the regimes in which a dependence of the correlation decay times on q3 rather than q2 applies. We conclude that quasielastic laser light scattering discloses little information about dynamics of internal motion of DNA chains. 相似文献
5.
Kumar Sanath Parvathi Ammini George Jeffy Krohne Georg Karunasagar Indrani Karunasagar Iddya 《World journal of microbiology & biotechnology》2009,25(3):527-531
Biofilms formed by the human pathogen Listeria monocytogenes in food-processing environments can be a potential source of contamination. In this study, we investigated the ability of
L. monocytogenes wild type and its laboratory-derived isogenic mutants in cwhA, prfA, agrA, flaA, degU, ami and sigB to adhere to and form biofilms on abiotic surfaces. The results suggest that inactivation of the two component regulatory
system degU completely abolished biofilm formation, while inactivation of the flagellar gene flaA, two component response regulator agrA and the autolysin-adhesin gene ami lead to severe impairment of initial attachment and the subsequent development of a mature biofilm by L. monocytogenes. Mutants in the global regulator of virulence prfA and the alternative sigma factor sigB were unaffected and formed biofilms similar to wild type L. monocytogenes. 相似文献
6.
降水对鄂尔多斯高原克隆植物分布的影响 总被引:1,自引:0,他引:1
鄂尔多斯高原地处半干旱区到干旱区的过渡带。通过沿鄂尔多斯高原从东到西的天然降水梯度的样带调查,分析了克隆植物的分布特征与降水的关系。结果表明:克隆植物的物种数量、占物种总数的比例和重要值以及根状茎型克隆植物的物种数量均与降水量呈显著正相关。5种优势植物克氏针茅、本氏针茅、黑沙蒿、赖草和短花针茅均为克隆植物,它们的分布也受降水影响。克氏针茅的密度、本氏针茅的盖度和密度、黑沙蒿的高度、盖度和密度以及赖草的高度均与降水量呈显著正相关。然而,赖草的盖度以及短花针茅的高度、盖度和密度均与降水量成负相关。因此,克隆植物在鄂尔多斯高原植被中具有重要作用,而且其作用随着降水量的增加而加强。 相似文献
7.
Sifa Mvoi Yan-Xia Lin Riccardo Biondini 《Biometrical journal. Biometrische Zeitschrift》1998,40(1):57-78
Consider a model yt = ft(θ) + Mt, 0 ⩽ t ⩽ T where θ∈ Θ in an unknown parameter, ft(θ) is a linear predictable process, Mt is a martingale difference, and the nature of E(M2t/ℱt—1) is unknown. This paper presents an estimating procedure for θ based on the asymptotic quasi-likelihood methodology. Conditions under which the asymptotic quasi-likelihood estimate converges to the true parameter θ0 are discussed. This method is applied to several simulated examples, and estimates of the unknown parameter are obtained by means of a two-stage technique. Comparison is made between the estimates obtained via this method and those obtained via the ordinary least squares method. Discussion is provided on the application of the model. 相似文献
8.
Milan Strakraba Iva Dostlkov Josef Hejzlar Vojtêch Vyhnlek 《International Review of Hydrobiology》1995,80(3):403-413
The annual average degree of phosphorus retention (both TP and OP) in reservoirs was found to depend mainly on the theoretical retention time (RT). The phosphorus retention (RP) is shown for some reservoirs in Czech Republic to be well approximated (standard deviation = 10.9) with RP(TP) = 74.7* (1-exp(-0.0255* RT)) (N = 38, 7 ≤ RT ≤ 604 days). The inclusion of 13 additional reservoirs for which data were assembled from literature resulted in an almost identical relationship: RP(TP) = 76.1* (1-exp(-0.0282* RT)) (N = 51, range of RT nearly unchanged). The retention of soluble reactive phosphorus RP(OP) studied on data from literature seems to be higher than that of TP. Statistical comparison with data for RP(TP) of lakes has shown a significantly lower retention in lakes than in reservoirs for comparable RP, resulting in RP(TP) = 66.0* (1-exp(-0.00419* RT)) (N = 59, 5.8 ≤ RT ≤ 260000 days). The differences between RP(OP) and RP(TP) and differentiation of lakes and reservoirs are discussed and a need for more thorough theoretical analysis stressed. Consequences for watershed management are summarized. 相似文献
9.
10.
JUDITH G. SMITH 《The Annals of applied biology》1976,83(1):15-29
The most abundant natural enemies of aphids on Brussels sprout crops were Syrphidae, different species being attracted differentially to weedy or weed-free plots according to whether they were more host-plant-orientated (e.g. Melanostoma spp., Platycheirus spp.) and thus affected directly by the background, or more aphid-orientated (e.g. Syrphus balteatus) and so less affected by background than by aphid numbers. Oviposition by Melanostoma spp. was usually much greater in weedy sprout crops than on sprouts in bare soil, and their eggs were also very abundant on weeds. Eggs of other syrphid species were scarcer on weeds. In contrast to Melanostoma, Platycheirus spp. usually oviposted preferentially on sprouts growing in bare soil. Oviposition by S. balteatus was in response to aphid abundance and thus tended to become greater on sprouts in bare soil. Notably more adults of non-aphido-phagous Syrphidae were caught over weedy than over non-weedy Brussels sprout plants. Anthocoris nemorum nymphs and adults were very common on sprout plants and weeds in the weedy crop but were scarce on sprouts in bare soil; A. nemorum oviposited on white and yellow charlock (Raphanus raphanistrum and Sinapis arvensis) occasionally. Parasitism of Brevicoryne brassicae by Diaeretiella rapae appeared to be related to aphid numbers and was only indirectly influenced by the crop background. Field experiments with green and brown cloth backgrounds showed that some syrphids were attracted to green; A. nemorum was relatively scarce over both artificial backgrounds. It is concluded that decreased natural enemy action is partly responsible for the initially greater abundance of B. brassicae in a weed-free crop of Brussels sprouts than in a weedy crop. 相似文献
11.
Johannes Becker-Follmann Andreas Gaa Elke Baùsch Ernst Natt Gerd Scherer Otto von Deimling 《Mammalian genome》1997,8(3):172-177
We have performed a high-resolution linkage analysis for the conserved segment on distal mouse Chromosome (Chr) 8 that is
homologous to human Chr 16q. The interspecific backcross used involved M. m. molossinus and an M. m. domesticus line congenic for an M. spretus segment from Chr 8 flanked by phenotypic markers Os (oligosyndactyly) and e, a coat colormarker. From a total of 682 N2 progeny, the 191 animals revealing a recombination event between these phenotypic markers were typed for 23 internal loci.
The following locus order with distances in cM was obtained: (centromere)–Os–4.1–Mmp2–0.2–Ces1,Es1, Es22–1.2–Mt1,D8Mit15–2.2–Got2, D8Mit11–3.7–Es30–0.3–Es2, Es7–0.9–Ctra1,Lcat–0.3–Cdh1, Cadp, Nmor1, D8Mit12–0.2–Mov34–2.5–Hp,Tat–0.2–Zfp4–1.6–Zfp1,Ctrb–10.9–e. In a separate interspecific cross involving 62 meioses, Dpep1 was mapped together with Aprt and Cdh3 at 12.9 cM distal to Hp, Tat, to the vicinity of e. Our data give locus order for markers not previously resolved, add Mmp2 and Dpep1 as new markers on mouse Chr 8, and indicate that Ctra1 is the mouse homolog for human CTRL. Comparison of the order of 17 mouse loci with that of their human homologs reveals that
locus order is well conserved and that the conserved segment in the human apparently spans the whole long arm of Chr 16.
Received: 30 July 1996 / Accepted: 15 November 1996 相似文献
12.
Bionomics of aphids reared on cereals and some Gramineae 总被引:1,自引:0,他引:1
G. J. W. DEAN 《The Annals of applied biology》1973,73(2):127-135
In controlled temperature, light and relative humidity, Metopolophium dirhodum and Sitobion avenae multiplied more on young Proctor barley than on Blenda oats, and less on Cappelle wheat. Rhopalosiphum padi increased in number fastest on barley and slowest on oats. More survived, and generation lengths seemed shorter, on barley for M. dirhodum and S. avenae and on wheat for R. padi. Tests with young cereals outdoors generally agreed with those in controlled conditions. On mature plants, there were more M. dirhodum on barley, more R. padi on wheat and more S. avenae on oats than on the other cereals. Given a free choice in large cages outdoors, most aphids were found on barley. When allowed to choose between grasses, more M. dirhodum were on Dactylis glomerata, Poa pratensis and Festuca pratensis, more R. padi on Lolium perenne and F. pratensis, and more S. avenae on D. glomerata and L. perenne. Most aphids of all species combined were on F. pratensis, Lolium and Phleum, and fewest on Festuca rubra and Holcus mollis. 相似文献
13.
James A. Koziol 《Biometrical journal. Biometrische Zeitschrift》1989,31(5):619-624
We propose a measure of multivariate kurtosis suggested from Mardia's measure of multivariate skewness b1,p, and examine its relationship both to Mardia's measure of multivariate kurtosis b2,p, and to a smooth test of multivariate kurtosis ǔ42. 相似文献
14.
Shigeo Kamiyama 《Bioscience, biotechnology, and biochemistry》2013,77(9):1091-1096
Leaf oil samples of four different citrus species were prepared from young leaves and the detailed composition of each leaf oil was investigated using gas chromatography, thin-layer chromatography and infrared spectrometry. The following components were identified: α-pinene, α-thujene, β-pinene, limonene, γ-terpinene, p-cymene, p-α-dimethylstyrene, β-humulene, β-selinene, trans-2-hexen-l-al, cis-3-hexen-l-ol, trans-2-hexen-l-ol, linalool terpinen-4-ol and α-terpineol. In addition, camphene, sabinene, β-myrcene, α-terpinene, β-elemene, caryophyllene, neral, geranial, nerol and geraniol were tentatively identified. Most of the components were found to be contained in common in the leaf oils of four different citrus species, but the relative contents of some of the components such as limonene, γ-terpinene, p-cymene, linalool, neral and geranial were distinctly different from species to species. Thus, gas chromatographic analyses of leaf oils seemed to be useful for the identification of citrus species. 相似文献
15.
Isolda Luna Helga Ochoterena 《Cladistics : the international journal of the Willi Hennig Society》2004,20(3):223-270
This work represents the first phylogenetic analysis of all genera belonging to the plant family Theaceae (sensu lato). The study is based on 60 morphological characters derived from herbarium specimens and an extensive literature review of 37 genera (including the outgroup). In contrast to the results from molecular data, Theaceae is here found to consist of one clade in which the recognition of two families or subfamilies would leave Theaceae s.s. paraphyletic. Within that clade, Ternstroemiaceae is supported as monophyletic and includes Adinandra, Anneslea, Archboldiodendron, Balthasaria, Cleyera, Eurya, Euryodendron, Ficalhoa, Freziera, Symplococarpon, Ternstroemia and Visnea. The paraphyletic Theaceae s.s. includes Apterosperma, Camellia, Dankia, Gordonia, Pyrenaria, Schima, and Stewartia. Tetrameristaceae (Pentamerista and Tetramerista) are supported as a monophyletic family, with Pellicieraceae (Pelliciera) as sister group, and that clade is sister to the rest of the taxa. Bonnetiaceae (Archytaea and Bonnetia) and Kielmeyeroideae of the Clusiaceae (Caraipa, Haploclathra, Kielmeyera, Mahurea, Marila, and Neotatea) are also supported as monophyletic. Given the differences between the results obtained from morphological and molecular data, we consider that there is still a need for further research, including combined analyses. 相似文献
16.
Influence of different B-complex recombinants on the outcome of Rous sarcomas in chickens 总被引:3,自引:0,他引:3
Seven major histocompatibility (B) complex recombinants were evaluated for anti-Rous sarcoma response. In experiment 1, the BR5(F21-G19) recombinant haplotype both homozygous and in heterozygous combinations with B19 and B21 haplotypes were compared to B19/B19 and B21/B21 chickens to determine the relative influence of the BF versus BG chromosomal segments on regression of Rous sarcoma virus-induced tumours. In experiment 2, six recombinant haplotypes BR1(F24-G23), BR2(F2-G23), BR3(F2-G23), BR4(F2-G23), BR6(F21-G23) and BR8(F2-G2a,23) present in chickens heterozygous for normal haplotypes B19, B23 or B26 were compared for anti-sarcoma response. A total of 1328 chickens were blood typed for B alloanti-gens at 17 days of age, inoculated in the wingweb with Rous sarcoma virus at 6 weeks and monitored for anti-tumour immune response over a 10-week period. Genotypes which shared the same BF haplotype, but differed in their BG regions, had similar anti-tumour responses, implicating the BF but not the BG region in tumour regression. Chickens carrying BF2 or BF21 had a strong anti-tumour response, while BF24 conferred a weaker response, regardless of the accompanying normal haplotype. 相似文献
17.
Following our established theoretical model to deal with the second-harmonic generation (SHG) excited by a linearly polarized
focused beam in type I collagen, in this paper, we further quantitatively characterize the differences between SHG emissions
in type I collagen excited by collimated and focused beams. The effects of the linear polarization angle (α) and the fibril polarity characterized by the hyperpolarizability ratio ρ on SHG emission has been compared under collimated and focused beam excitation, respectively. In particular, SHG emission
components along the i axis ( I2w,i )\left( {I_{2\omega {,}i} } \right) (i = x,y,z), the induced SHG emission deviation angle γ
ij
, and the detected SHG signals (I
2ω,ij
) in the ij plane by rotating the applied polarizer angle φ
ij
have been investigated (i = x, x, y; j = y, z, z). Results show that under our simulation model, SHG emission in the xy plane, such as I
2ω,x
,I
2ω,y
,γ
xy
and I
2ω,xy
varying as polarization angle (α) under collimated and focused light, presents no significant difference. The reverse of the fibril polarity has induced great
impact on I
2ω,x
,γ
xy
and I
2ω,xy
in both collimated and focused light. I
2ω,x
and γ
xy
show similarity, but I
2ω,xy
at α = 30° demonstrates a slight difference in focused light to that in collimated light. Under focused light, the reverse of
fibril polarity causes obvious changes of the collected SHG intensity I
2ω,xz
and I
2ω,yz
at a special polarization angle α = 60° and γ
xz
, γ
yz
along α. 相似文献
18.
Takeshi Takahashi 《Bioscience, biotechnology, and biochemistry》2013,77(1):38-47
An attempt was made to clarify how Pellicularia filamentosa f. sp. microsclerotia IFO 6298 capable of hydroxylating C21-steroids at the C-19 position converts C19-steroids, especially monohydroxyderivatives of androst-4-ene-3, 17-dione. Such substrates as 11β-hydroxyandrost-4-ene-3,17-dione (I), androst-4-ene-3, 11, 17-trione (II), androsta-1,4-diene-3, 17-dione (III), 11β-hydroxyandrosta-1,4-diene-3,17-dione (IV), 14α-hydroxyandrost-4-ene-3, 17-dione (V), 15α-hydroxyandrost-4-ene-3, 17-dione (VI) and 9α-hydroxyandrost-4-ene-3, 17-dione (VII) were converted by the organism. All the main and several minor products were then isolated and identified. As a result it is concluded that this organism converts I and II into 14α-hydroxyandrost-4-ene-3,11,17-trione, III and IV into 14α-hydroxyandrosta-1,4-diene-3,1l,17-trione, V into 11α 14α dihydroxyandrost-4-ene-3, 17-dione (main) and 11β, 14α-dihydroxyandrost-4-ene-3, 17-dione (minor, a tentative structure), VI into 11β, 15α-dihydroxyandrost-4-ene-3,17-dione (main) and 15α-hydroxyandrost-4-ene-3,11,17-trione (minor, a tentative structure) and VII into 9α, 14α-dihydroxyandrost-4-ene-3, 17-dione (main) and 6β, 9α-dihydroxyandrost-4-ene-3,17-dione (minor).In addition, the structural requirement of substrate for the 19-hydroxylation catalyzed by the organism and the influence of a hydroxyl group on steroid nucleus upon the 11β- and 14α-hydroxylations and the 11β-OH-dehydrogenation was discussed. 相似文献
19.
Two rivers in Norway were treated with rotenone in an effort to eradicate the salmon parasite, Gyrodactylus salaris. Rotenone induced an immediate catastrophic invertebrate drift, mainly of dead individuals. The response to rotenone with respect to degree and timing varied widely. Baetis rhodani, Isoperla sp. and Rhyacophila nubila displayed a strong increase in drift densities early in the treatment. Baetis niger, Ameletus inopinatus, Heptagenia sp. and Agapetus ochripes showed a delayed response. Ephemerella aurivillii, E. mucronata, Taeniopteryx nebulosa and Elmis aenea drifted at low densities throughout the treatment. Early larval instar tended to be more sensitive to rotenone than later instar, and the toxic effect of rotenone tended to increase with increasing water temperature. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
20.
Studies on the bacterial diseases of Sudan crops 总被引:2,自引:0,他引:2
New records are presented of bacterial diseases affecting the following weed plants: Heliotropium sudanicum, Rhynchosia memnonia, Vigna radiata, V. pubigera, Euphorbia acalyphoides and Phyllanthus niruri. Bacterial leaf blight of pigeon pea (Cajanus cajan) caused by Xanthomonas phaseoli f. cajani is reported for the first time from the Sudan. The causal bacteria, all of which belong to the genus Xanthomonas, are compared with related pathogens. The differences between these bacteria are considered of little diagnostic value. Pathogenically, they can be separated into three groups: (i) the Heliotropium pathogen; (ii) the bacteria affecting leguminous plants; and (iii) the bacteria affecting species of the family Euphorbiaceae. Because of the diversity in opinion on speciation in the genus Xanthomonas, two alternative proposals are put forward. In the first, Xanthomonas is considered a monotypic genus with X. campestris as the sole species. The pathogens reported in this work from previously unrecorded hosts, which proved to differ in pathogenicity from established ones, are considered to be new formae speciales. These are X. campestris f.sp. heliotropii from H. sudanicum, X. campestris f.sp. rhynchosiae from R. memnonia, X. campestris f.sp. vigna-radiatae from V. radiata, X. campestris f.sp. euphorbiae from E. acalyphoides and X. campestris f.sp. phyllanthii from P. niruri. The organism from V. pubigera is accordingly identified as X. campestris f.sp. vignicola. Other bacteria used for comparison are also reduced to ff.sp. of X. campestris. The other proposal is to lump together pathogens with overlapping host ranges in a single species that comprises a number of ff.sp. differing in pathogenicity. Thus the bacteria from leguminous plants are all considered to belong to X. phaseoli as previously suggested by Sabet. New ff.sp. are created for the pathogens from R. memnonia (X. phaseoli f.sp. rhynchosiae), and V. radiata (X. phaseoli f.sp. vigna-radiatae). The organism from V. pubigera is identified in this case as X. phaseoli f.sp. vignicola. The bacteria from members of the Euphorbiaceae are considered to belong to X. ricini on priority grounds. X. cassavae and X. poinsettiaecola which have been used for comparison are reduced to the ff.sp. X. ricini f.sp. cassavae and f.sp. poinsettiaecola respectively. Two new ff.sp. are created: for E. acalyphoides pathogen, X. ricini f.sp. euphorbiae and for P. niruri pathogen, X. ricini f.sp. phyllanthii. The creation of a new species (X. heliotropii sp.nov.) is proposed for the Heliotropium pathogen. The present study shows that many weed plants may be affected with new bacterial strains that can also infect cultivated crops. 相似文献