Electrophoretic behavior of the H+-ATPase proteolipid from bovine heart mitochondria

The proteolipid subunit of H⁺-ATPase was labeled by [¹⁴C]N,N-dicyclohexylcarbodiimide in bovine heart mitochondria. The radioactive labeling was followed using various systems of sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE). When using discontinuous SDS-PAGE (Laemmli, U.K., 1970,Nature (London)227, 680–685) a monomeric (Mr 7600±1500) and a dimeric form (Mr 17,800±1200) of the proteolipid were detected, while only the monomeric form was found on urea (8 M) containing gels (SDS-PAGE according to Laemmli; or Swank, R. T., and Munkers, K. D., 1971,Anal. Biochem. 39, 462–477). When using SDS-PAGE with Na-P_i buffer (Weber, K., and Osborn, M., 1969,J. Biol. Chem. 244, 4406–4442), only a dimeric form of the proteolipid (Mr 15,000±1000) was detected. Experimental data indicate that the different patterns of proteolipid separation are related to the presence of the two distinct proteolipid conformations in the SDS solution.     

Stoichiometry of bacterial anaerobic oxidation of elemental sulfur by ferric iron

The conventional stoichiometry of the oxidation of elemental sulfur by ferric iron in Acidithiobacillus ferrooxidans was not in agreement with our experimental data in terms of ferrous iron and proton formation. Reaction modelling under the actual conditions of bacterial activity resulted in a different stoichiometry, where additional iron species participate in the process to affect the number of released protons. The suggested reaction equation may more accurately predict the intensity of environmental acidification during the anaerobic bioprocess.     

A key role for E-cadherin in intestinal homeostasis and Paneth cell maturation

Background

E-cadherin is a major component of adherens junctions. Impaired expression of E-cadherin in the small intestine and colon has been linked to a disturbed intestinal homeostasis and barrier function. Down-regulation of E-cadherin is associated with the pathogenesis of infections with enteropathogenic bacteria and Crohn''s disease.

Methods and Findings

To genetically clarify the function of E-cadherin in intestinal homeostasis and maintenance of the epithelial defense line, the Cdh1 gene was conditionally inactivated in the mouse intestinal epithelium. Inactivation of the Cdh1 gene in the small intestine and colon resulted in bloody diarrhea associated with enhanced apoptosis and cell shedding, causing life-threatening disease within 6 days. Loss of E-cadherin led cells migrate faster along the crypt-villus axis and perturbed cellular differentiation. Maturation and positioning of goblet cells and Paneth cells, the main cell lineage of the intestinal innate immune system, was severely disturbed. The expression of anti-bacterial cryptidins was reduced and mice showed a deficiency in clearing enteropathogenic bacteria from the intestinal lumen.

Conclusion

These results highlight the central function of E-cadherin in the maintenance of two components of the intestinal epithelial defense: E-cadherin is required for the proper function of the intestinal epithelial lining by providing mechanical integrity and is a prerequisite for the proper maturation of Paneth and goblet cells.     

Novel antimicrobial peptides from the venom of the eusocial bee Halictus sexcinctus (Hymenoptera: Halictidae) and their analogs

Two novel antimicrobial peptides, named halictines, were isolated from the venom of the eusocial bee Halictus sexcinctus. Their primary sequences were established by ESI-QTOF mass spectrometry, Edman degradation and enzymatic digestion as Gly-Met-Trp-Ser-Lys-Ile-Leu-Gly-His-Leu-Ile-Arg-NH₂ (HAL-1), and Gly-Lys-Trp-Met-Ser-Leu-Leu-Lys–His-Ile-Leu-Lys-NH₂ (HAL-2). Both peptides exhibited potent antimicrobial activity against Gram-positive and Gram-negative bacteria but also noticeable hemolytic activity. The CD spectra of HAL-1 and HAL-2 measured in the presence of trifluoroethanol or SDS showed ability to form an amphipathic α-helical secondary structure in an anisotropic environment such as bacterial cell membrane. NMR spectra of HAL-1 and HAL-2 measured in trifluoroethanol/water confirmed formation of helical conformation in both peptides with a slightly higher helical propensity in HAL-1. Altogether, we prepared 51 of HAL-1 and HAL-2 analogs to study the effect of such structural parameters as cationicity, hydrophobicity, α-helicity, amphipathicity, and truncation on antimicrobial and hemolytic activities. The potentially most promising analogs in both series are those with increased net positive charge, in which the suitable amino acid residues were replaced by Lys. This improvement basically relates to the increase of antimicrobial activity against pathogenic Pseudomonas aeruginosa and to the mitigation of hemolytic activity.     

Chromosome counts of some Mongolian plants

The paper gives the chromosome numbers of 45 species from 72 Mongolian localities, belonging to the genera:Amygdalus, Asparagus, Astragalus, Cancrinia, Caragana, Chamaerhodos, Chelidonium, Chesneya, Dianthus, Hypecoum, Lathyrus, Lilium, Oxytropis, Papaver, Potentilla, Schizonepeta, Sibbaldia, Thermopsis, Trifolium, Trigonella, Vicia. Chromosome morphology of three species ofChamaerhodos and taxonomical remarks on some other species are added. A new combinationSibbaldia sericea (Grubov) Soják is proposed.     

Effects of age and physical performance capacity on distribution and composition of high-density lipoprotein subfractions in men

The influences of age and maximal aerobic capacity (VO2max) on serum lipoproteins with special regard to the concentration, composition and distribution of high density lipoprotein (HDL) subfractions were investigated in 51 healthy males of different characteristics: younger than 35 years, untrained (n = 14, mean age 28.2 years, SD 6.0; VO2max, 47.9 ml.kg-1.min-1, SD 5.8) and trained (n = 11, mean age 27.9 years, SD 4.3; VO2max, 61.1 ml.kg-1.min-1, SD 5.1), older than 50 years untrained (n = 14, mean age 58.9 years, SD 5.9, VO2max, 29.3 ml.kg-1.min-1, SD 5.3) and trained (n = 12, mean age 59.3 years, SD 7.2, VO2max, 45.7 ml.kg-1.min-1, SD 7.7). The fasting-state serum concentrations of total cholesterol, tri-acylglycerol and lipoprotein-cholesterol were measured. The HDL-subfractions were separated by density (rho) gradient ultracentrifugation. Concentrations of cholesterol, cholesterylester, tri-acylglycerol, phospholipids, apolipoprotein (apo) A-I and A-II were measured in the subfractions HDL2b: rho = 1.063-1.100 g.ml-1; HDL2al: rho = 1.00-1.110 g.ml-1; HDL2a2: rho = 1.110-1.150 g.ml-1; HDL3: rho = 1.150-1.210 g.ml-1. Elderly untrained subjects showed increased serum concentrations of total-, very low- and low density lipoprotein-cholesterol and elevated tri-acylglycerol levels. The HDL-cholesterol concentration was decreased, due to reduced concentrations of HDL2-subfractions. Significant changes in the composition of HDL2-subfractions were found in elderly untrained subjects. The HDL2-subfractions had more protein, a decreased apoA-I:A-II ratio and less phospholipids in comparison to HDL2-subfractions from younger untrained and trained, and elderly trained subjects.(ABSTRACT TRUNCATED AT 250 WORDS)     

Condition and feeding behaviour of subadult burbot (<Emphasis Type="Italic">Lota lota</Emphasis>) in riverine and lacustrine environments

The condition and feeding behaviour of burbot, a widespread potamodromous species in riverine and lacustrine environments, were compared in order to evaluate the importance of both in three artificial systems. Subadult burbot were sampled in three temperate reservoirs in spring, and one of them also in summer and autumn. Standardised abundance and sizes of burbot were comparable between the reservoirs, but the conditions were significantly different. The Clark’s condition coefficient and index of fullness were independent of burbot size and individuals. Feeding behaviour in terms of abundance and composition of consumed food was environment-dependent. The most common prey category was aquatic insect larvae, dominating in the riverine environment. Permanent water invertebrates, microcrustaceans, beetles and crayfish were less common food and eaten more often in the lacustrine environment. Prey-fish were usually the most common species of suitable size. The food analyses demonstrated opportunistic feeding behaviour with selection of prey associated with benthic habitat and suitable size. Burbot is therefore flexible not only in environments utilisation, but also feeding strategy.     

Involvement of protein phosphorylation in the sensitivity of photosystem II to strong illumination

Four types of differently phosphorylated hylakoids isolated from field grown spinach ( Spinacia oleracea L.) were tested for the sensitivity of photosystem II (PSII) to photoinactivation. Phosphorylation of light-harvesting II complexes (LHCII) protected PSII electron transfer from photoinhibitory damage, while the phosphorylation of the PSII core polypeptides slightly accelerated the decline of electron transfer during high irradiance treatment. Dephosphorylation of the CP43 apoprotein and PsbH protein by an alkaline phosphatase resulted in an extreme sensitivity of the thylakoids to strong illumination. The PSII photoinactivation of thylakoids with the impaired oxygen-evolving complex was found to be independent of phosphorylation.
The thylakoids of the thermophilic cyanobacterium Synechococcus elongates were used in order to compare the plants with an organism where LHCII complexes are missing and the PSII core proteins are not phosphorylated.     

Loss of neuronal Miro1 disrupts mitophagy and induces hyperactivation of the integrated stress response

Clearance of mitochondria following damage is critical for neuronal homeostasis. Here, we investigate the role of Miro proteins in mitochondrial turnover by the PINK1/Parkin mitochondrial quality control system in vitro and in vivo. We find that upon mitochondrial damage, Miro is promiscuously ubiquitinated on multiple lysine residues. Genetic deletion of Miro or block of Miro1 ubiquitination and subsequent degradation lead to delayed translocation of the E3 ubiquitin ligase Parkin onto damaged mitochondria and reduced mitochondrial clearance in both fibroblasts and cultured neurons. Disrupted mitophagy in vivo, upon post‐natal knockout of Miro1 in hippocampus and cortex, leads to a dramatic increase in mitofusin levels, the appearance of enlarged and hyperfused mitochondria and hyperactivation of the integrated stress response (ISR). Altogether, our results provide new insights into the central role of Miro1 in the regulation of mitochondrial homeostasis and further implicate Miro1 dysfunction in the pathogenesis of human neurodegenerative disease.     

Transgenic ipt tobacco overproducing cytokinins overaccumulates phenolic compounds during in vitro growth.

We present evidence that overproduction of endogenous cytokinins (CK) caused stress response in non-rooting Pssu-ipt transgenic tobacco (Nicotiana tabacum L.) grown in vitro. It was demonstrated by overaccumulation of phenolic compounds, synthesis of pathogenesis related proteins (PR proteins), and increase in peroxidase (POD) activities. Immunolocalization of zeatin and also PR-1b protein on leaf cryo-sections proved their accumulation in all mesophyll cells of transgenic tobacco contrary to control non-transgenic plants. Intensive blue autofluorescence of phenolic compounds induced by UV in cross-sections of leaf midrib showed enhanced contents of phenolics in transgenic tobacco compared with controls, nevertheless, no significant difference between both plant types was found in leaf total lignin content. Transgenic plantlets exhibited higher peroxidase activities of both soluble and ionically bound fractions compared with controls. HPLC analysis of phenolic acids confirmed the increase in all phenolic acids in transgenic tobacco except for salicylic acid (SA). The effect of high phenolic content on rooting of transgenic tobacco is discussed.