The effect of salts on the kinetics of iron release from N-terminal and C-terminal monoferrictransferrins

The kinetics of iron release from N-terminal and C-terminal monoferric human transferrins has been studied using EDTA as the accepting chelate. In the absence of added salts iron release from the N-terminal site is more facile but the relative lability can be reversed by the addition of NaClO₄, NaCl and LiCl. The results indicate that both anions and cations can affect the lability of the two sites. Since the relative lability of the two monoferrictransferrins is affected by fairly moderate concentrations of NaCl and NaClO₄ we suggest that the ionic composition serum may play an important role in determining the observed distribution of iron among the sites. A new method for the preparation of N-terminal monoferrictransferrin is described.     

Cold hardiness of rhododendron cultivars grown in different photoperiods and temperatures

Two rhododendron cultivars, 'Pohjola's Daughter' and 'Helsinki University', were grown at +15 and +24°C, each combined with a photoperiod of 14 h (short day, SD) or 20 h (long day, LD). After a 112-day growing season, they were subjected to a hardening regime of fortnightly decreasing temperature (+9, +5, +1 and −2°C) and a 12-h photoperiod, except that part of the plants grown in LD had LD also at +9 and +5°C. At −2°C, all plants were in darkness. Controlled freezing tests of the leaves were performed before each change in temperature. The injury was evaluated visually and by electrolyte leakage (EL) tests. The observations on the visual assessment were analysed with logit models, and the EL data with non-linear sigmoid functions. The visually scored 50% damage (VD₅₀) correlated better with the EL tests than 10 or 90% damage. Photoperiod and temperature during the growing season affected the cold hardiness of both cultivars, but they differed in their responses. 'Pohjola's Daughter' benefited from SD as well as from high temperature, while 'Helsinki University' attained better hardiness at a cool growing season temperature and was less sensitive to photoperiod.     

Single-step Strep-tag purification for the isolation and identification of protein complexes from mammalian cells

Identification of protein complexes is the key to understanding cellular functions. In this study, we present a novel method for the identification of multiprotein complexes from mammalian cells. By using the Strep-tag affinity chromatography method, enabling fast and simple one-step purification, coupled with competitive elution under physiological conditions, we successfully purified a PP2A holoenzyme protein complex from a cultured mammalian cancer cell line. We identified, by mass spectrometry, both known and novel interacting proteins for PP2A, and demonstrate that the purified PP2A complex is functional. The benefits and potential applications of the Strep-tag method for protein complex purification are discussed.     

Application of beta-irradiation through the struts of a previously deployed stent

The application of beta-radiation in coronary arteries is a promising new technique for the treatment of in-stent restenosis. This is the first case in which the 5 F. delivery catheter of the Beta-Cath trade mark system was advanced through the struts of a stent, previously deployed in an adjacent branch, so as to deliver radiation to the target vessel.     

Identification to the species level of <Emphasis Type="Italic">Lactobacillus</Emphasis> isolated in probiotic prospecting studies of human,animal or food origin by 16S-23S rRNA restriction profiling

Background  

The accurate identification of Lactobacillus and other co-isolated bacteria during microbial ecological studies of ecosystems such as the human or animal intestinal tracts and food products is a hard task by phenotypic methods requiring additional tests such as protein and/or lipids profiling.     

Long-day induction of flowering in Lolium temulentum involves sequential increases in specific gibberellins at the shoot apex

One challenge for plant biology has been to identify floral stimuli at the shoot apex. Using sensitive and specific gas chromatography-mass spectrometry techniques, we have followed changes in gibberellins (GAs) at the shoot apex during long day (LD)-regulated induction of flowering in the grass Lolium temulentum. Two separate roles of GAs in flowering are indicated. First, within 8 h of an inductive LD, i.e. at the time of floral evocation, the GA(5) content of the shoot apex doubled to about 120 ng g(-1) dry weight. The concentration of applied GA(5) required for floral induction of excised apices (R.W. King, C. Blundell, L.T. Evans [1993] Aust J Plant Physiol 20: 337-348) was similar to that in the shoot apex. Leaf-applied [(2)H(4)] GA(5) was transported intact from the leaf to the shoot apex, flowering being proportional to the amount of GA(5) imported. Thus, GA(5) could be part of the LD stimulus for floral evocation of L. temulentum or, alternatively, its increase at the shoot apex could follow import of a primary floral stimulus. Later, during inflorescence differentiation and especially after exposure to additional LD, a second GA action was apparent. The content of GA(1) and GA(4) in the apex increased greatly, whereas GA(5) decreased by up to 75%. GA(4) applied during inflorescence differentiation strongly promoted flowering and stem elongation, whereas it was ineffective for earlier floral evocation although it caused stem growth at all times of application. Thus, we conclude that GA(1) and GA(4) are secondary, late-acting LD stimuli for inflorescence differentiation in L. temulentum.     

Morphological differences among egg nests and adult individuals of Cicadatra persica (Hemiptera,Cicadidae), distributed in Erneh,Syria

The aim of this study is determining the different patterns of egg nests and the morphological differences between the specimens of Cicadatra persica Kirkalidy, 1909 (Hemiptera: Cicadidae) distributed in fruit orchards in Erneh located on AL-Sheikh mountain south west of Syria. The appearance of 80 egg nests was studied, and the results showed that there were two basic patterns of egg nests laid by Cicadatra persica, 90% of the egg nests were of the first pattern (consists of several adjacent slits), while 10% of them were of the second pattern (consists of several divergent slits). A random sample consisting of 300 specimens (150 males and 150 females) were also studied concentrating on the differences in the color of the supra-antennal plate and in the number of spurs on the tibia of the hind legs. The results showed that there were two basic patterns of individuals based on the differences in the color of supra-antennal plate. The first pattern (individuals with yellow supra-antennal plates), constituted more than 90%, and the second one (individuals with black supra-antennal plates) constituted less than 10%. The results also showed that there were 27 different patterns based on the number of spurs on the tibia of the hind legs. One of them was a common pattern (2, 3) whose individuals have 2 spurs on the upper side of the tibia of the hind legs and 3 spurs on the lateral side of the tibia of the hind legs. The total percent of this common pattern was 76%. The other 26 patterns were different from each other, and the total percent of all these different patterns was 24%.     

Collagenase predigestion on paraffin sections enhances collagen immunohistochemical detection without distorting tissue morphology

Reliable immunohistochemical detection of collagen in formalin fixed, paraffin embedded tissues requires protease digestion. While these pan-proteases (pepsin, trypsin, protease K, etc.) enhance collagen detection, they also digest many other tissue proteins and produce poor cellular morphology and unrecognizable cellular structures. Balancing the conditions (protease type, concentration, incubation time and temperature) to digest some, but not all, proteins in a tissue section while optimizing collagen detection requires one to compromise improved collagen immunolabeling with adequate cellular morphology. Furthermore, optimal conditions for digesting tissue proteins to enhance collagen detection vary among tissue types and their fixation. Although brain is not typically subject to these deleterious consequences, structures such as epithelium, spermatids, stroma etc. and other tissues with complicated histology are profoundly affected. To resolve this technical dilemma, we discovered a novel use for collagenase to enhance collagen immunodetection without affecting the noncollagen proteins, thereby preserving tissue morphology. Collagenase, which is typically used in vitro for disassociation of cells, has never been used reliably on formalin fixed, paraffin embedded tissue sections. This new use of collagenase for immunohistochemistry promotes increased collagen immunolabeling, is easy to use, is versatile, and allows preservation of tissue structure that provides maximal and accurate histological information.     

Identification of abscisic acid from shoots of Salix pentandra

Abscisic acid isolated from vegetative shoots of Salix pentandra L. has been identified by high performance liquid chromatography and combined gas chromatography-mass spectrometry.     

Abscisic acid and cessation of apical growth in Salix pentandra

Effects of exogenous abscisic acid (ABA) on growth and transpiration in seedlings of two ecotypes of Salix pentandra L. were studied in phytotron experiments. Application of ABA resulted in increased stomatal resistance, reduced transpiration and reduced growth rate. ABA did not induce cessation of apical growth in seedlings grown under a 24-h photoperiod. The content of endogenous ABA in seedlings grown under 24-h (LD) or 12-h (SD) photoperiods was analysed from purified methanol extracts using gas chromatography and electron capture detection. No significant differences were found in the ABA contents of LD- and SD-grown plants. SD-induced cessation of apical growth was not associated with increased stomatal resistance or reduced transpiration rate.