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1.
The enzymes chlorocatechol-1,2-dioxygenase, chloromuconate cycloisomerase, dienelactone hydrolase, and maleylacetate reductase allow Ralstonia eutropha JMP134(pJP4) to degrade chlorocatechols formed during growth in 2,4-dichlorophenoxyacetate or 3-chlorobenzoate (3-CB). There are two gene modules located in plasmid pJP4, tfdC(I)D(I)E(I)F(I) (module I) and tfdD(II)C(II)E(II)F(II) (module II), putatively encoding these enzymes. To assess the role of both tfd modules in the degradation of chloroaromatics, each module was cloned into the medium-copy-number plasmid vector pBBR1MCS-2 under the control of the tfdR regulatory gene. These constructs were introduced into R. eutropha JMP222 (a JMP134 derivative lacking pJP4) and Pseudomonas putida KT2442, two strains able to transform 3-CB into chlorocatechols. Specific activities in cell extracts of chlorocatechol-1,2-dioxygenase (tfdC), chloromuconate cycloisomerase (tfdD), and dienelactone hydrolase (tfdE) were 2 to 50 times higher for microorganisms containing module I compared to those containing module II. In contrast, a significantly (50-fold) higher activity of maleylacetate reductase (tfdF) was observed in cell extracts of microorganisms containing module II compared to module I. The R. eutropha JMP222 derivative containing tfdR-tfdC(I)D(I)E(I)F(I) grew four times faster in liquid cultures with 3-CB as a sole carbon and energy source than in cultures containing tfdR-tfdD(II)C(II)E(II)F(II). In the case of P. putida KT2442, only the derivative containing module I was able to grow in liquid cultures of 3-CB. These results indicate that efficient degradation of 3-CB by R. eutropha JMP134(pJP4) requires the two tfd modules such that TfdCDE is likely supplied primarily by module I, while TfdF is likely supplied by module II.  相似文献   

2.
Summary The rare autosomal fragile site, fra (16)(q22), is the most common of all rare autosomal fragile sites and has a heterozygote frequency of about 5%. Evidence for it was found following the segregation expected from a simple codominant trait with complete penetrance; this is in contrast to a variety of other rare autosomal fragile sites. Based on the analysis of 12 families in which fra (16)(q22) is segregating, we found that, whereas complete penetrance could be confirmed, the transmitting parent was significantly more likely to be of the female sex. On the other hand, there was no evidence for preferential transmission to offspring of either sex.  相似文献   

3.
Eight specimens of Sericolophus reflexus (Ijima) were compared with the holotype of Hernandeziana ijimae (Hernandez) to assess suspected synonymy of these taxa. An extensive morphometric analysis of the spicules available in these specimens of variable condition show that the H. ijimae holotype exhibits characters near the centre of the range of S. reflexus. It is concluded that H. ijimae is a junior synonym of S. reflexus , and that the family Corythophoridae de Laubenfels is invalid by preoccupation of its base generic name.  相似文献   

4.
Mitochondria are well-characterized intracellular organelles usually concentrated in locations of high energy consumption. Light microscopic and transmission electron microscopic observations of the internal anatomy of the feather mites Diplaegidia columbae and Falculifer rostratus were conducted. In the anterior half of the bodies of the mites, we found several dozen of distinctive mitochondria-rich (MR) cells filled with abundant, large mitochondria. Mitochondria are placed individually or enclosed in small groups within an elaborated lamellar system forming a mitochondria–lamellae complex (MLC). The role of the MLC as well as the MR cells is not clear at present, but their involvement in heat generation is hypothesized and briefly discussed.  相似文献   

5.
Cis-dichloro-bis (isopropylamine) trans-dihydroxy platinum (IV) (CHIP) is a second generation platinum coordination complex now in Phase II clinical trials. In vitro studies with Chinese Hamster Ovary cell cultures show that CHIP is a phase-sensitive drug, being most cytotoxic to cells in early G1 phase and least toxic to late S and G2 phase cells. The dose-modifying factor between the drug sensitivity of cells treated in G1 and in late S phase is 1.6. These findings and their clinical significance are discussed with respect to the phase sensitivity of other cytotoxic agents.  相似文献   

6.
Abstract. Cis-dichloro-bis (isopropylamine) trans-dihydroxy platinum (IV) (CHIP) is a second generation platinum coordination complex now in Phase II clinical trials. In vitro studies with Chinese Hamster Ovary cell cultures show that CHIP is a phase-sensitive drug, being most cytotoxic to cells in early G1 phase and least toxic to late S and G1 phase cells. the dose-modifying factor between the drug sensitivity of cells treated in G1 and in late S phase is 1.6. These findings and their clinical significance are discussed with respect to the phase sensitivity of other cytotoxic agents.  相似文献   

7.
Four allelic forms of serum plasminogen (PLG) were detected in baboons (Papio hamadryas Linneaus 1758) by isoelectric focusing and were determined to be inherited as autosomal codominant traits. Linkage analysis of data from 179 progeny and their parents revealed that PLG is tightly linked (lod score = 30.20) to the gene encoding apolipoprotein(a) (LPA), as in humans. No recombinant individuals were identified. This is the first linkage detected between PLG and LPA in any species other than humans and is the first genetic linkage identified in a nonhuman primate species by family studies.  相似文献   

8.
Exechia and Bibio have retained several plesiomorphic groundplan features of Diptera and Bibionomorpha, including a fully exposed and sclerotized head capsule, the transverse undivided labrum, the absence of movable premandibles, and undivided mandibles without combs. The fusion of the hypostomal bridge with the head capsule and largely reduced antennae are derived features shared by both taxa. The absence of teeth at the anterior hypostomal margin is a potential autapomorphy of Bibionomorpha. A basal position of Anisopodidae is suggested by a number of plesiomorphies retained in this family. Apomorphies of Bibionomorpha excluding Anisopodidae are the reduction of tentorial elements, the partial fusion of the labrum and clypeus, one-segmented antennae, the absence of a separate submental sclerite, the loss of the labial palpus, and the reduction of the pharyngeal filter apparatus. Head structures of Bibio are largely unmodified. The subprognathous orientation is one of few autapomorphic features. In contrast, the mouthparts of Exechia are highly modified in correlation with the specialized food uptake. The rasping counterrotating movements of maxillae and mandibles with teeth oriented in opposite directions are carried out by strongly developed extensors and flexors of the paired mouthparts. The modified labium mechanically supports the “drill head” formed by the mandibles und maxillae. The necessary stability of the head capsule is provided by the hypostomal bridge which also compensates the far-reaching reduction of the tentorium.  相似文献   

9.
The origins of capers, their use and cultivation are discussed. Capers seeds and charcoal are often recovered from archaeological sites of the Mediterranean and West Asia. These are referred to as C. Spinosa L. This is mostly a group of cultivars restricted to localities surrounding the Western Mediterranean and some places in the Eastern Mediterranean. Identification of the findings is discussed in terms of seed morphology, present distribution and ancient uses of C. aegyptia Lam., C. sicula Veill., C. cartilaginea Decne, C. orientalis Veill., C. decidua (Forssk.) Edgew. and other species. Citations of Capparis in early Rabbinic, Mesopotamian and Greco-Roman texts are presented. Received June 3, 2002 / Accepted October 8, 2002 Correspondence to: D. Rivera  相似文献   

10.
Summary The rare fragile site at 16q22 was experimentally induced in lymphocyte cultures with various AT-specific, non-intercalating DNA-ligands. The optimum conditions for the induction of fra (16)(q22) were determined. The best expression of fra (16)(q22) was found with the aromatic diamidine berenil which is recommended for further studies on this fragile site. The results indicate that fra (16)(q22) is a region with AT-rich, late replicating DNA. The simultaneous treatment of lymphocytes with berenil and aphidicolin (inhibitor of DNA polymerase ) induces both the rare fra (16) (q22) and the common fra (16) (q23) within the same chromosome. A population study on 350 unselected individuals showed that fra (16)(q22) is the most common of all rare autosomal fragile sites in man. The frequency of individuals heterozygous for fra (16)(q22) is 5.1% no homozygosity for fra (16) (q22) was detected. Statistical analysis indicates that the population is in Hardy-Weinberg equilibrium with respect to the fragile and non-fragile chromosomes 16.  相似文献   

11.
The biology of the fruit fly Bactrocera tau, an important horticultural pest, was studied under laboratory conditions at 25°C and 60–70% relative humidity on Cucurbita maxima. The duration of mating averaged 408.03 ± 235.93 min. After mating, the female fly had a preoviposition period of 11.7 ± 4.49 days. The oviposition rate was 9.9 ± 8.50 eggs and fecundity was 464.6 ± 67.98 eggs/female. Eggs were elliptical, smooth and shiny white, turning darker as hatching approached, and measured 1.30 ± 0.07 mm × 0.24 ± 0.04 mm. The chorion has polygonal microsculpturing and is species-specific with polygonal walls. The egg period lasts for 1.3 ± 0.41 days. The duration of the larval period is 1.2 ± 0.42, 1.7 ± 0.48 and 4.0 ± 0.94 days for first, second and third instars, respectively. Pupation occurs in the sand or soil and pupal periods are 7.0 ± 0.47 days. The life cycle from egg to adult was completed in 14.2 ± 1.69 days; the longevity of mated females and males was 130.33 ± 14.18 and 104.66 ± 31.21 days, respectively. At least two to three generations were observed from June 2008 to June 2009.  相似文献   

12.
Sim GE  Goh CJ  Loh CS 《Plant cell reports》2008,27(8):1281-1289
We analysed the endogenous cytokinin levels of Dendrobium Madame Thong-In seedlings grown in vitro during vegetative and flowering-inductive periods. HPLC was used to fractionate the extracts and radioimmunoassay (RIA) was used for assay of zeatin (Z), dihydrozeatin (DZ), N(6)-(Delta(2)-isopentenyl)-adenine (iP) and their derivatives. Coconut water used in experiments was found to contain high level (>136 pmol ml(-1)) of zeatin riboside (ZR). Protocorms and seedlings cultured in medium with coconut water were found to contain 0.5-3.9 pmol g(-1) FW of the cytokinins analysed. Seedlings (1.0-1.5 cm) cultured in flowering-inductive liquid medium containing 6-benzyladenine (BA, 4.4 muM) and coconut water (CW, 15%) contained up to 200 and 133 pmol g(-1) FW of iP and iPA, respectively. These levels were significantly higher than all other cytokinins analysed in seedlings of the same stage and were about 80- to 150-folds higher than seedlings cultured in non-inductive medium. During the transitional (vegetative to reproductive) stage, the endogenous levels of iP (178 pmol g(-1) FW) and iPA (63 pmol g(-1) FW) were also significantly higher than cytokinins in the zeatine (Z) and dihydrozeatin (DZ) families in the same seedlings. Seedlings that grew on inductive medium but remained vegetative contained lower levels of iPA. The importance of the profiles of iP and its derivatives in induction of in vitro flowering of D. Madame Thong-In is discussed.  相似文献   

13.
Ruthenium(II) tris(bipyridine)-centered poly(ethylenimine) (Ru PEI) was synthesized via acid hydrolysis of Ru tris(bipyridine)-centered poly(2-ethyl-2-oxazoline) (Ru PEOX), and the luminescence, DNA entrapment, and transfection efficiencies were evaluated. Emission maxima for Ru PEI samples are red-shifted compared to Ru PEOX precursors, and the luminescence lifetimes are shorter in both methanol and aqueous solutions. Slower oxygen quenching of Ru PEOX and Ru PEI luminescence versus [Ru(bpy)3]Cl2 (bpy = bipyridine) is attributed to polymer shielding effects. Ru PEI luminescence is similar in the presence and absence of DNA. Ru PEI (7900 Da) and linear PEI (L-PEI; 22,000 Da) fully entrapped DNA (5.4 kb; pcDNA) at an N/P ratio of 2. LNCaP prostate cancer cells were transfected with a plasmid encoding for green fluorescent protein using Ru PEI and L-PEI vectors for comparison. For N/P = 48, the transfection efficiency for Ru PEI was approximately 50% relative to that of L-PEI.  相似文献   

14.
Cytokinesis in bacteria is mediated by a macromolecular machine known as the divisome, consisting of an assembly of FtsZ polymers around the cylindrical axis of the cell and the downstream regulators of division that are subsequently recruited to it. FtsZ polymerizes into filaments in a GTP-dependent manner, similarly to its eukaryotic structural homolog tubulin. The initial placement of the FtsZ polymerization site is tightly regulated by multiple mechanisms, as are the subsequent polymer reshaping and force generation that separate the two daughter cells from each other. New factors have been recently discovered that contribute to this regulation, notably affecting FtsZ polymer shaping, and modulating FtsZ polymerization in response to the metabolic or redox state of the cell.  相似文献   

15.
Abstract. Multivariate morphometric analysis (canonical variates) was used to discriminate between closely related taxa within the Myzus persicae group. It is demonstrated that dark green, anholocyclic populations with a 2n=13 or 2n=14 karyotype in Europe, hitherto treated as a form or biotype of M.persicae, all conform to a discrete morphometric grouping and should therefore be treated as a separate taxonomic entity, permanently isolated from the M.persicae gene pool. It is suggested that this taxon was first described as Siphonophora antirrhinii by Macchiati in 1883. A discriminant function is provided to separate most individual apterae of antirrhinii from those of persicae. Myzus icelandicus Blackman sp.n., on Caryophyllaceae and other plants in Iceland, is distinguished from M.polaris H.R.L. and M.certus (Walker), and a key is given to apterous virginoparae of the species of the M.persicae group in Europe.  相似文献   

16.
The functional regulation of integrins is a major determinant of cell adhesion, migration and tissue maintenance. The binding of cytoskeletal proteins to various sites of integrin cytoplasmic domains is a key mechanism of this functional regulation. Expression of recombinant integrin alpha(IIb)beta(3) and alpha(M)beta(2) lacking the GFFKR-region in CHO cells results in constitutively activated integrins. In contrast, CHO cells stably expressing either a GFFKR-deleted alpha(V(del))beta(3) or a FF to AA-substituted alpha(V(AA))beta(3) do not reveal a constitutively activated integrin. Adhesion to immobilized fibrinogen is strongly impaired in alpha(V(del))beta(3) or alpha(V(AA))beta(3)-expressing cells, whereas it is not impaired in alpha(IIb)beta(3) and alpha(M)beta(2), both lacking the GFFKR-region. In a parallel plate flow chamber assay, alpha(V)beta(3)-expressing cells adhere firmly to fibrinogen and spread even at shear rates of 15 to 20 dyn/cm(2), whereas alpha(V(del))beta(3) or alpha(V(AA))beta(3) cells are detached at 15 dyn/cm(2). Actin stress fiber formation and focal adhesion plaques containing alpha(V)beta(3) are observed in alpha(V)beta(3) cells but not in alpha(V(del))beta(3) or alpha(V(AA))beta(3)-expressing cells. As an additional manifestation of impaired outside-in signaling, phosphorylation of pp125(FAK) was reduced in these cells. In summary, we report that the GFFKR-region of the alpha(V)-cytoplasmic domain and in particular two phenylalanines are essential for integrin alpha(V)beta(3) function, especially for outside-in signaling. Our results suggest that the two beta(3)-integrins alpha(IIb)beta(3) and alpha(V)beta(3) are differentially regulated via their GFFKR-region.  相似文献   

17.
Protonephridia in marine streptoneuran gastropods are describedfor the first time. The organization of these paired organsof the intracapsular veliger larva of Nassarius reticulatusis described. The ciliary flame is formed by a single terminalcell. The duct is formed by one tubular cell and the aperturalcell, which forms the lips of the excretory pore. In addition,the surface of the apertural cell is covered to a great extentby the post-velar bud cell (usually termed ‘larval kidney’).Protonephridia like these are considered to be widely distributedamong streptoneuran gastropods. The homology of these organswith those of opis-thobranchs and pulmonates is suggested. Thepost-velar buds (= ‘larval kidneys’) are suggestedas a synapomorphous character of Caenogastropoda. The functionof the postvelar buds is discussed taking into considerationthe existence of a protonephridium and a possible functionalconnection between these two structures. (Received 14 June 1990; accepted 1 September 1990)  相似文献   

18.
Crystals of Pt(DMSO)4(TFMS)2 have been prepared by dissolution of platinum(II) hydroxide in a solution of CF3SO3H in DMSO and subsequent evaporation. The structure was determined by use of a CAD-4 diffractometer with monochromatic Mo Kα radiation. The space group is P with Z = 2, a = 8.630(2), b = 9.557(3), c = 16.659(3) Å, α = 73.33(2), β = 77.38(2) and γ = 79.19(3)°. The refinement converged to R = 0.056. The coordination around platinum is distorted square-planar with two S- and two O-bonded DMSO ligands in a cis-arrangement. The four donor atoms and the platinum are coplanar within 0.03 Å. There is a severe steric crowding between the two S-bonded DMSO molecules, which gives rise to a distortion of the bond angles around the platinum. The crowding is minimized as much as possible by a staggered arrangement of oxygen atoms and methyl groups of adjacent ligands. Pt---S bond lengths 2.208(3) and 2.205(4) Å are significantly shorter that those in the corresponding palladium complex, in accordance with a much stronger bond in the case of platinum. Bond length comparisons also indicate that ground state transinfluence of S-bonded DMSO probably is about the same in platinum and palladium complexes.  相似文献   

19.
This protocol describes the synthesis of oligo(poly(ethylene glycol) fumarate) (OPF; 1-35 kDa; a polymer useful for tissue engineering applications) by a one-pot reaction of poly(ethylene glycol) (PEG) and fumaryl chloride. The procedure involves three parts: dichloromethane and PEG are first dried; the reaction step follows, in which fumaryl chloride and triethylamine are added dropwise to a solution of PEG in dichloromethane; and finally, the product solution is filtered to remove by-product salt, and the OPF product is twice crystallized, washed and dried under vacuum. The reaction is affected by the molecular weight of PEG and reactant molar ratio. The OPF product is cross-linked by radical polymerization by either a thermally induced or ultraviolet-induced radical initiator, and the physical properties of the OPF oligomer and resulting cross-linked hydrogel are easily tailored by varying PEG molecular weight. OPF hydrogels are injectable, they polymerize in situ and they undergo biodegradation by hydrolysis of ester bonds. The expected time required to complete this protocol is 6 d.  相似文献   

20.
Summary A population ofHalictus (S.) tumulorum, a species whose biology is poorly known, was studied in eastern France. The polyphenism was evaluated by comparing a sample of foundresses (1991) with two samples of summer females (1991 and 1992).H. tumulorum is a primitively eusocial species with castes differing only slightly in size, but more in function, and producing numerous males in the first brood. The social level of the species appears rather low.  相似文献   

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