Heterogeneous production of laccase by mycelium of white-rot fungi

Mycelium of white-rot fungi secretes laccase into the medium. It was found by cultivation on malt-agar plates that the mycelium does not produce laccase equally in all its parts. The youngest hyphae at the margins of the colony represent usually the maximum producers, whereas older hyphae produce less or none at all. An exception here isCollybia velutipes which is the weakest producer of laccase of all the fungi studied and where only the older hyphae begin to secrete it. Manometric estimation of laccase showed that maximum specific activity of laccase is achieved at the boundary between the phases of initial and linear growth and i₁₁ some cases during the first half of linear growth. Ageing of the mycelium characterized by certain changes in its metabolism is reflected in changes of enzyme production by fungal hypha of different age.     

Gibberellin and sympodial branching inTilia

U r?stově na za?átku fyziologického odpo?inku inhibovaných rostlinTilia platyphyllos Scop. aTilia cordata Mill. se vlivem giberelové kyseliny (GA₃) zachoval terminální pupen jako náznak monopodiálního větvení, co? lze vylo?it jako fylogenetickou rekapitulaci. P?itom se ukázalo, ?e po?et normálně na letorostech zachovávaných list? je p?edur?en ji? v pupenech.     

Localization of GABA-like immunoreactivity in the ectostriatum of domestic chicks: GABA immunocytochemistry combined with Golgi impregnation

Brain Cell Biology - The distribution of GABA-like immunoreactivity (GABA-LI) in the ectostriatal core (Ec) of domestic chicks (one to two days old) was investigated using (1) preembedding GABA...     

CGRP-immunoreactive sensory nerve fibers in the submandibular gland of the rat

Summary Indirect immunofluorescence technique was used to study the occurrence and distribution of CGRP immunoreactivity in the submandibular gland of normal rats and after unilateral sensory and sympathetic denervations. In normal rats, CGRP-immunoreactive nerve fibers and nerve trunks were seen around or in close contact with interlobular salivary ducts as well as around small blood vessels of the gland. Occasionally, CGRP-immunoreactive nerve fibers were also detected between or around the acini of the gland.The submandibular ganglia contained CGRP-immunoreactive nerve fibers, but the ganglion cells were not immunoreactive for CGRP. The trigeminal ganglion contained a population of CGRP-immunoreactive, mainly small sized ganglion cells and nerve fibers distributed throughout the ganglion. Unilateral electrocoagulation of the trigeminal nerve caused a significant reduction in the number of immunoreactive nerve fibers in the gland, although some fibers still were present in the ipsilateral glandular tissue. Unilateral superior cervical ganglionectomy caused no detectable effect on the number of CGRP-immunoreactive nerve fibers in the gland.The present results suggest that the rat submandibular gland contains CGRP-immunoreactive nerve fibers both around blood vessels and in glandular secretory elements. Denervation experiments support the view that the majority, but perhaps not all of them originate from the trigeminal ganglion.     

Effect of a Single Dose of β,β''-Iminodipropionitrile In Vivo on the Properties of Neurofilaments In Vitro: Comparison with the Effect of Iminodipropionitrile Added Directly to Neurofilaments In Vitro

The biochemical properties of neurofilaments isolated from control and iminodipropionitrile-treated rats were compared with regard to autophosphorylation capacity, hydrolysis of ATP, and the formation of a viscous gel between filaments. Both preparations exhibited a similar polypeptide composition, and no covalent cross-linking between neurofilament subunits was induced by iminodipropionitrile in vivo. An ATPase activity, systematically present in all preparations, was unaffected by the administration of iminodipropionitrile to the rats. Conversely, the autophosphorylation of neurofilament subunits in vitro was significantly higher in preparations from iminodipropionitrile-treated rats than from control animals, with a marked increase of the phosphorylation of a high molecular weight neurofilament-associated protein. Iminodipropionitrile provoked a higher gelation capacity of neurofilaments as measured in vitro, with a lower critical concentration for the preparation from treated animals. A similar increased interaction was obtained with millimolar concentrations of iminodipropionitrile added to bovine neurofilaments in vitro, involving likely neurofilament-associated molecules, because the effect of the drug was lost after their extraction by 0.8 M KCl. These results support the hypothesis that iminodipropionitrile interferes with the neurofilament networks through a preferential interaction with the neurofilament-associated proteins, resulting in a change in their properties and consequently in an increased capacity of interaction between the polymers.     

Diet and urinary estrogen profile in premenopausal omnivorous and vegetarian women and in premenopausal women with breast cancer

The urinary estrogen profile was studied in the midfollicular phase twice, and diet four times during 1 yr in 10 premenopausal breast cancer (BC) patients consuming an omnivorous normal Finnish diet and in two control groups, one consuming an omnivorous (n = 12) and the other a lactovegetarian (n = 11) diet. Total fat intake in relation to caloric intake was almost identical in all three groups. Only with regard to grain fiber intake did the BC patients differ significantly from both other groups. No differences were found between the groups with regard to urinary excretion of 13 individual estrogens and total estrogens, with the exception of 4-hydroxyestrone (4-OH-E1), which was significantly lower (P less than 0.05) in the BC group than in the vegetarians. A high carbohydrate to protein ratio in the diet had a negative correlation with the excretion of 2-hydroxyestrogens and 2-hydroxyesterone (2-OH-E1) to 4-OH-E1 ratio. The BC group had significantly higher urinary 2-OH-E1 to E1 ratio (P less than 0.05) compared to the vegetarians. The 2-OH-E1 to 4-OH-E1 ratio was highest in the BC group (= 7.1) and differed significantly from that of the omnivores (= 4.3; P less than 0.02) and vegetarians (= 3.6; P less than 0.005). This ratio showed a negative correlation with intake of carbohydrates, starch, total and grain fiber. Urinary excretion of 4-OH-E1 correlated positively with total and grain fiber intake and plasma SHBG. Protein intake correlated positively with urinary 2-methoxy-E1 excretion, and retinol intake positively with catechol estrogen, E1 and E2 excretion. It is concluded that estrogen production and urinary estrogen profile in premenopausal breast cancer patients is normal with the exception of a low 4-OH-E1 excretion and high urinary 2-OH-E1 to 4-OH-E1 ratio. This ratio, which seems to depend on diet, is the only urinary estrogen parameter separating premenopausal BC patients from the control omnivorous and lactovegetarian women.     

Binding of a distamycin-ellipticine hybrid molecule to DNA and chromatin: spectroscopic, biochemical, and molecular modeling investigations.

A bifunctional molecule in which an ellipticine chromophore is attached to a distamycin residue via a diaminopropyl tether has been designed and synthesized in the expectation of creating a hybrid molecule capable of bidentate binding to DNA by both intercalation and minor-groove interactions. The strength and mode of binding to DNA of this conjugate have been studied by means of circular and linear dichroism as well as by stopped-flow kinetics and measurements of reactivity toward a chemical probe. The results converge to reveal that the ellipticine moiety of the hybrid largely dominates the binding reaction with DNA. In the presence of chromatin, the hybrid molecule binds preferentially to the internucleosomal DNA, a preference dictated by its intercalating chromophore. Theoretical computations were performed on the comparative complexation energies of distamycin, the ellipticine derivative, and the hybrid ligand with a B-representative octanucleotide, d(GCATATGC)2. The best binding configuration of the ellipticine derivative locates its aminoalkyl side chain in the minor groove where distamycin is also present. The molecular modeling analysis fully supports the involvement of a bimodal binding process for the hybrid and reveals that the binding of the conjugate to DNA favors a pronounced bending toward the minor groove. This effect is attributed to intercalation of the ellipticine chromophore. An interesting link is established between the DEPC reactivity experiments and the theoretical computations, suggesting that DEPC can be used as a probe for drug-induced DNA bending. On the basis of these results, we propose the design of a new hybrid ligand bearing an additional positively-charged amidine side chain to confer higher DNA-binding affinity.