Expression patterns of loricrin in various species and tissues

Abstract. In this study we analyzed the expression patterns of loricrin in various species and tissues using immunohistochemistry, immunoblotting and Northern blots. Loricrin is a glycine-, serine- and cysteine-rich protein expressed very late in epidermal differentiation in the granular layers of normal mouse and human epidermis. Later on in differentiation, loricrin becomes cross-linked as a major component into the cornified cell envelope by the formation of N^ɛ -(γ-glutamyl)lysine isopeptide bonds. This process either occurs directly or by the intermediate accumulation in L-keratohyaline granules of mouse epidermis and human acrosyringia. Loricrin was identified in all mammalian species analyzed by virtue of its highly conserved carboxy-terminal sequences revealing an electric mobility of ∼60 kDa in rodents, rabbit and cow and of ∼35 kDa in lamb and human on sodium dodecyl sulfate polyacrylamide gel electrophoresis. Loricrin is expressed in the granular layer of all mammalian orthokeratinizing epithelia tested including oral, esophageal and fore-stomach mucosa of rodents, tracheal squamous metaplasia of vitamin A deficient hamster and estrogen induced squamous vaginal epithelium of ovary ectomized rats. Loricrin is also expressed in a few parakeratinizing epithelia such as BBN [N-butyl-N-(4–hydroxybutyl)nitrosamine]-induced murine bladder carcinoma and a restricted subset of oral and single vaginal epithelial cells in higher mammals. Our results provide further evidence that the program of squamous differentiation in internal epithelia of the upper alimentary tract in rodents and higher mammals differ remarkably. In addition, we also have noted the distinct distribution patterns of human loricrin and involucrin, another major precursor protein of the cornified cell envelope.     

The susceptibility of plants to Agrobacterium: A discussion of the role of phenolic compounds

Abstract An extensive literature survey of the host-range of Agrobacterium -induced neoplasms has revealed that highly susceptible plant families are accumulators of polyphenolics, whereas families assumed to be non-sensitive to the pathogen seem to lack this property. These and other results might indicate that polyphenolics play a role in the host-pathogen relationship of Agrobacterium -induced neoplasms. This hypothesis will be discussed in the light of the present knowledge of crown gall/hairy root induction and progress in plants.     

β-adrenoceptors in human tracheal smooth muscle: characteristics of binding and relaxation

Specific binding of [¹²⁵I]-(−)-cyanopindolol to human tracheal smooth muscle membranes was saturable, stereo-selective and of high affinity (K_d=5.3±0.9 pmol/l and R_T=78±7fmol/g tissue). The β₁-selective antagonists atenolol and LK 203-030 inhibited specific [¹²⁵I]-(−)-cyanopindolol binding according to a one binding site model with low affinity in nearly all subjects, pointing to a homogeneous β₂-adrenoceptor population. In one subject using LK 203-030 a small β-adrenoceptor subpopulation could be demonstrated. The beta-mimetics isoprenaline, fenoterol, salbutamol and terbutaline recognized high and low affinity agonist binding sites. Isoprenaline's pK_H- and pK_L- values for the high and low affinity sites were 8.0±0.2 and 5.9±0.3 respectively. In functional experiments isoprenaline relaxed tracheal smooth muscle strips having intrinsic tone with a pD₂-value of 6.63±0.19.     

Single-stranded DNA used as an efficient new vehicle for transformation of plant protoplasts

In relation to the question which DNA form (single- or double-stranded) is transferred by Agrobacterium tumefaciens to plant cells, we studied the behaviour of single-stranded DNA, as compared to double-stranded DNA, when it is introduced into plant protoplasts by electroporation. To this end, we cloned a construct with a plant NPTII gene as well as a CAT gene in the M13 vectors tg130 and tg131. We found that both complementary single-stranded molecules gave rise to substantial CAT activity in plant protoplasts, suggesting that single-stranded DNA is converted into double-stranded DNA by the plant cell replication machinery. Unexpectedly, we found that single-stranded DNA leads to a 3–10 fold higher frequency of stable transformation (selection for kanamycin resistance) than double-stranded DNA. These results indicate that the use of single-stranded DNA might be considered in experiments in which optimal transformation frequencies are needed, e.g. with protoplasts form recalcitrant plant species.Abbreviations ss single-stranded - ds double-stranded - CAT chloramphenicol acetyl transferase - NPTII neomycin phosphotransferase II - RT room temperature