Expression of α-d-mannosidase in man-hamster somatic cell hybrids

Two types of -d-mannosidase isozymes are present in human white blood cells, human diploid fibroblasts, and HeLa cells. One of these (the S isozyme) constitutes the major -d-mannosidase of the human cells, has a pH optimum of 4.4, and is associated with lysosomes. The other (the F isozyme) is most active at pH 6, is acid labile, and is located in the soluble portion of the cytoplasm. The expression of human lysosomal -d-mannosidase was examined in man-hamster hybrid clones, and was found to be concordant with that of phosphohexose isomerase in 54 of 55 primary clones. A locus specifying human lysosomal -d-mannosidase has therefore been assigned to chromosome 19.This work was supported by NIH Grants HD 04807-07 and HD 06285-04 and by a research grant (5 PO 1 HB 06276-04) to the Mental Retardation Research Center of the Children's Hospital Medical Center, Boston, Massachusetts, from the NIH.     

An evaluation of some morphological traits in doubled haploid lines and their F1 hybrids of head cabbage Kamienna Głowa in the vegetative phase

The internal stump length, head mass and head shape of doubled haploid (DH) lines and their F1 hybrids of head cabbage Kamienna G?owa were compared. It was found that the range of variation in the investigated traits of DH lines was higher than that of their F1 hybrids. The head mass of the DH lines indicated some level of inbreeding depression, but their F1 hybrids showed a significant effect of heterosis. Genes responsible for flattened head shape were dominant over rounded shape genes. The longer internal stump trait was dominant over the shorter one.     

Antitumour and antimalarial activity of artemisinin–acridine hybrids

Artemisinin–acridine hybrids were prepared and evaluated for their in vitro activity against tumour cell lines and a chloroquine sensitive strain of Plasmodium falciparum. They showed a 2–4-fold increase in activity against HL60, MDA-MB-231 and MCF-7 cells in comparison with dihydroartemisinin (DHA) and moderate antimalarial activity. Strong evidence that the compounds induce apoptosis in HL60 cells was obtained by flow cytometry, which indicated accumulation of cells in the G1 phase of the cell cycle.     

Selective benzoylation of some N-acetyl-N-aryl-β-D-xylopyranosylamines

Selectivity in the benzoylation of N-acetyl-N-p-methoxyphenyl-, -p-bromophenyl-, and -p-chlorophenyl-β-D-xylopyranosylamines has been demonstrated. The structures of the products was shown by using periodate oxidation and n.m.r. spectroscopy. The relative reactivity of the hydroxyl groups was HO-3 ≈ HO-4 > HO-2. The β-D-xylopyranosylamine derivatives were shown to possess the ⁴C¹ conformation.     

Will hybrids of genetically modified crops invade natural communities?

A perceived danger of genetic modification of crops is that crop hybrids may not only become more-pernicious weeds of agriculture but that they may also become invasive of natural communities. New information on the extent of crop hybridization and the characteristics of modified crops is facilitating more-accurate assessments of these risks.     

Products of acylase and β-Lactamase hydrolysis of some penicillins

The products of acylase of acylase and β-lactamase hydrolysis of 7 penicillins were determined by paper chromatography. The procedures used allowed us to detect also the product without antibiotic activity. When benzylpenicillin, phenoxymethylpenicillin, and ampicillin were hydrolyzed by cell suspension ofAlcaligenes faecalis of a high acylase activity, penicic acid and another unidentified metabolite, were found beside 6—APA. The hydrolysis of benzylpenicillin byEscherichia coli produced the same metabolites with prevailing benzylpenicilloic acid. The way of formation of penicic acid is discussed. Purified β-lactamase and cell suspension of the test or penicillin-resistent strain ofStaphylococcus aureus produced in all penicillins tested the same metabolite-corresponding penicilloic acid.     

The identity of some taxa of Schizophragma （Saxifragaceae）

After examining a large number of type and authoritative specimens of Schizophragma Siebold ＆ Zucc., S. elliptifolium C. F. Wei and S. integrifolium var. glaucescens Rehder were reduced to synonyms of S. hypoglaucum Rehder and S. integrifolium f. cordatum S. Y. Wang was reduced to synonym of S. corylifolium Chun. Schizophragma crassum var. ellipticum J. Anthony was treated as the correct name of S. crassum var. hsitaoanum （Chun） C. F. Wei. The name S. integrifolium var. minus Rehder is reinstated. The taxonomic treatment is supported by leaf epidermal characters.     

Introgression of the Haynaldia villosa genome into γ-ray-induced asymmetric somatic hybrids of wheat

To study the effect of -ray treatment on donor and derived somatic hybrids, we carried out -ray donor treatment experiments with a wide range of -ray dosages and asymmetric somatic hybridization between protoplasts of wheat (Triticum aestivum L. Jinan 177) and protoplasts of Haynaldia villosa Schur. treated with different dosages of -rays (40, 60 and 80 Gy, respectively). We first screened the putative hybrids by isozyme analysis, followed by characterization of nuclear and organellar genome composition of the hybrids. Genomic in situ hybridization on mitotic metaphases demonstrated that the donor chromosome elimination in the hybrids increased with increased -ray dosage. Intergenomic chromosome recombination/translocations were observed in the hybrids from different dosages of -rays. PCR amplification of 5S rDNA spacer sequences showed that only some of the regenerated hybrid clones inherited donor 5S rDNA sequences, suggesting that the donor DNA was also eliminated randomly. Restriction fragment length polymorphism analysis using mitochondrion (mt) and chloroplast (cp) gene-specific probes showed that the hybrid calli contained mt genomes of both parents and the cp genome of only one of the parents. Recombinations between parental mt as well as cp genes were found in the hybrid clones. Furthermore, development of the hybrid clones was dependent on the -ray dosage used for the donor treatment. Regenerated plants were only obtained from fusion combinations of low (40 Gy) and intermediate (60 Gy) dose irradiation. The possible role and significance of -rays on the introgression of small segments of donor chromosomes to the receptor is discussed.     

Synthesis,characterization and antimalarial activity of quinoline–pyrimidine hybrids

The aim of this study was to synthesize a series of quinoline–pyrimidine hybrids and to evaluate their in vitro antimalarial activity as well as cytotoxicity. The hybrids were brought about in a two-step nucleophilic substitution process involving quinoline and pyrimidine moieties. They were screened alongside chloroquine (CQ), pyrimethamine (PM) and fixed combinations thereof against the D10 and Dd2 strains of Plasmodium falciparum. The cytotoxicity was determined against the mammalian Chinese Hamster Ovarian cell line. The compounds were all active against both strains. However, hybrid (21) featuring piperazine linker stood as the most active of all. It was found as potent as CQ and PM against the D10 strain, and possessed a moderately superior potency over CQ against the Dd2 strain (IC₅₀: 0.157 vs 0.417 μM, ～threefold), and also displayed activity comparable to that of the equimolar fixed combination of CQ and PM against both strains.     

Does migration of hybrids contribute to post-zygotic isolation in flycatchers?

In the face of hybridization, species integrity can only be maintained through post-zygotic isolating barriers (PIBs). PIBs need not only be intrinsic (i.e. hybrid inviability and sterility caused by developmental incompatibilities), but also can be extrinsic due to the hybrid's intermediate phenotype falling between the parental niches. For example, in migratory species, hybrid fitness might be reduced as a result of intermediate migration pathways and reaching suboptimal wintering grounds. Here, we test this idea by comparing the juvenile to adult survival probabilities as well as the wintering grounds of pied flycatchers (Ficedula hypoleuca), collared flycatchers (Ficedula albicollis) and their hybrids using stable isotope ratios of carbon (delta13C) and nitrogen (delta15N) in feathers developed at the wintering site. Our result supports earlier observations of largely segregated wintering grounds of the two parental species. The isotope signature of hybrids clustered with that of pied flycatchers. We argue that this pattern can explain the high annual survival of hybrid flycatchers. Hence, dominant expression of the traits of one of the parental species in hybrids may substantially reduce the ecological costs of hybridization.     

Production of trigeneric (barley × wheat) × rye hybrids

Summary Rye (Secale cereale cv. Prolific 2n=14 and 2n =14 + 2B was crossed onto hybrids between barley (Hordeum vulgare 2n = 14) and wheat (Triticum aestivum 2n= 42). Pollinated florets were injected with GA₃ to promote fertilization and hybrid embryo development. At 16 days after pollination the watery caryopses were removed, embryos dissected and cultured on a modified B₅ medium. Approximately 20% of the cultured embryos produced both roots and coleoptile and developed into viable seedlings. Viable seeds were also obtained at a low frequency from the same cross combinations. The hybrids were wheat-like except for the hairy neck characteristic of rye. There were 35 chromosomes in somatic tissue; 21 wheat, 7 barley and 7 rye. The rye chromosomes were distinguishable by their larger size and terminal C-bands. A lower seed set was obtained using pollen from rye plants with 2n=14 + 2B chromosomes than from plants without B chromosomes.Contribution No. 577, Ottawa Research Station     

Design,synthesis and anticancer evaluation of tetrahydro-β-carboline-hydantoin hybrids

A series of new tetrahydro-β-carboline-hydantoin hybrids have been designed and synthesized based on the structure of the known Eg5 inhibitor HR22C16. These compounds have been evaluated for their anticancer activity against lung (A549), cervical (ME180, HeLa), prostate (PC-3) and breast (MCF-7) cancer cell lines by MTT assay. These hybrids have displayed significant in vitro cytotoxicity in comparison to etoposide against PC-3, A549, and MCF-7 cell lines. The hybrids 3a, 3b, 3c, 3e, 3f, 3g, 4b, 4c, 4e and 4f appear to be more effective against the PC-3 cell line, among which compound 4b displayed the highest cytotoxicity (6.08 ± 0.2, IC₅₀ μM). Based on these results, an attempt was made to rationalize their mechanism of action through cell cycle analysis studies. The flow-cytometric analysis of compound 4b in PC-3 cells indicated a G2/M cell cycle arrest. Molecular docking studies substantiate that these compounds indeed bind to the allosteric site of Eg5 formed from Glu116, Gly117, Glu118, Trp127, Ala133, Ile136, Pro137, Tyr211, Leu214, and Glu215 residues with the most potent compound 4b showing the most favorable interaction.     

Somatic hybrids of Solanum tuberosum – application to genetics and breeding

Cultivated potato (Solanum tuberosum L.) is one of the first agricultural crops successfully cultured in vitro and used for obtaining of somatic hybrids. The review presents the current state of knowledge of somatic hybridisation involving this and other species from the genus of Solanum. Methods of somatic hybridisation, in particular factors that must be considered during designing the experiments are presented and discussed. The main attention however is focused on processes that are responsible for somatic hybrid formation. Complex interactions between genomes and plasmones lead to formation of symmetric, asymmetric and cytoplasmic recombinants. The concept of alloplasmic incompatibility is presented and discussed in relation to Solanum hybrids. Selected examples of potato somatic hybrids with agronomically important traits derived from wild species are presented in the table and discussed.     

Emission M?ssbauer studies of some organocobalamins

Subtle changes in the M?ssbauer parameters are observed while going from methyl- to ethyl- to adenosylcobalamin, and also when the "base" is detached from the cobalt. The observation of these changes demonstrates that the Co-C bond, among others, remains intact after the Auger event, accompanying the electron-capture decay of the cobalt-57. The differences between ethylcobalamin and the other two organocobalamins in the magnitude of the quadrupole splittings have been interpreted on the basis of the sigma-donating tendency of the organic moiety and the Co-C bond length. The latter is presumably determined by the steric hindrance offered to the group in approaching the cobalt atom. The ethyl- and adenosylcobalamins in their "base-off" form exhibit a larger quadrupole splitting than the corresponding "base-on" form. In the "bas-off" form, the cobalt atom is perhaps raised above the mean plane of the four equatorial nitrogen atoms of the corrin ring, which may result in the diminution of the delocalization of the 3dpi electron density. The higher population of dpi orbitals and the enhanced metallic character of the dz2, resulting from shrinkage of the Co-C bond length, enhances the magnitude of the quadrupole splitting.     

α-mannosidase and mannanase of some wood-rotting fungi

Cultivation media from 11 wood-rotting fungi contained α-mannosidase and mannanase activity. α-Mannosidase was studied in more detail inPhellinus abietis and mannanase was studied more intimately in basidiomycetesPhellinus abietis, Trametes sanguinea andPholiota aurivella. Suitable cultivation conditions and optimum conditions for the production of α-mannosidase and mannanase were determined. Both enzymes are constitutive; mannanase is extracellular, α-mannosidase was found in both mycelium and cultivation medium.     

Development of cyanopyridine–triazine hybrids as lead multitarget anti-Alzheimer agents

A series of new cyanopyridine–triazine hybrids were designed, synthesized and screened as multitargeted anti-Alzheimer’s agents. These molecules were designed while using computational techniques and were synthesized via a feasible concurrent synthetic route. Inhibition potencies of synthetic compounds 4a–4h against cholinesterases, Aβ_1–42 disaggregation, oxidative stress, cytotoxicity, and neuroprotection against Aβ_1–42-induced toxicity of the synthesized compounds were evaluated. Compounds 4d and 4h showed promising inhibitory activity on acetylcholinesterase (AChE) with IC₅₀ values 0.059 and 0.080 μM, respectively, along with good inhibition selectivity against AChE over butyrylcholinesterase (BuChE). Molecular modelling studies revealed that these compounds interacted simultaneously with the catalytic active site (CAS) and the peripheral anionic site (PAS) of AChE. The mixed type inhibition of compound 4d further confirmed their dual binding nature in kinetic studies. Furthermore, the results from neuroprotection studies of most potent compounds 4d and 4h indicate that these derivatives can reduce neuronal death induced by H₂O₂-mediated oxidative stress and Aβ_1–42 induced cytotoxicity. In addition, in silico analysis of absorption, distribution, metabolism and excretion (ADME) profile of best compounds 4d and 4h revealed that they have drug like properties. Overall, these cyanopyridine–triazine hybrids can be considered as a candidate with potential impact for further pharmacological development in Alzheimer’s therapy.