A reliable method for storage of tailed phages

A universal and effective method for long-term storage of bacteriophages has not yet been described. We show that randomly selected tailed phages could be stored inside the infected cells at −80 °C without a major loss of phage and host viability. Our results suggest the suitability of this method as a standard for phage preservation.     

Yeast ubiquitin ligase Rsp5 contains nuclear localization and export signals

The Rsp5 ubiquitin ligase regulates numerous cellular processes. Rsp5 is mainly localized to the cytoplasm but nuclear localization was also reported. A potential nuclear export signal was tested for activity by using a GFP(2) reporter. The 687-LIGGIAEIDI-696 sequence located in the Hect domain was identified as a nuclear export signal active in a Crm1-dependent manner, and its importance for the localization of Rsp5 was documented by using fluorescence microscopy and a lacZ-based reporter system. Analysis of the cellular location of other Rsp5 fragments fused with GFP(2) indicated two independent potential nuclear localization signals, both located in the Hect domain. We also uncovered Rsp5 fragments that are important to targeting/tethering Rsp5 to various regions in the cytoplasm. The presented data indicate that Rsp5 ligase is a shuttling protein whose distribution within the cytoplasm and partitioning between cytoplasmic and nuclear locations is determined by a balance between the actions of several targeting sequences and domains.     

Enhanced expression of Fas Ligand (FasL) in the lower airways of patients with fibrotic interstitial lung diseases (ILDs)

The exact role of FasL, and particularly its soluble and membrane-bound forms, in the development of chronic ILDs and lung fibrosis has not been extensively explored. We aimed at analyzing membrane-bound FasL expression on alveolar macrophages (AM) and lymphocytes (AL) as well as soluble FasL (sFasL) levels in bronchoalveolar lavage (BAL) from ILDs patients, incl. pulmonary sarcoidosis (PS), hypersensitivity pneumonitis (HP), silicosis, asbestosis, idiopathic pulmonary fibrosis (IPF), nonspecific interstitial pneumonia (NSIP), and healthy subjects (n = 89, 12, 7, 8, 23, 6, 17, respectively). In IPF, significantly increased percentage of AM FasL(+) and CD8(+)FasL(+) cells as well as sFasL levels in BAL were found. Increased sFasL levels were also observed in HP. NSIP and asbestosis were characterized by higher AM FasL(+) relative number; CD8(+)FasL(+) population was expanded in asbestosis only. There was a significant decline in AL FasL(+) percentage in PS and HP. Vital capacity was negatively correlated with sFasL levels, AM FasL(+) and CD8(+)FasL(+) cell relative count. CD4(+)FasL(+) and CD8(+)FasL(+) percentage strongly correlated with BAL neutrophilia, an unfavorable prognostic factor in lung fibrosis. The concurrent comparative BAL analysis of FasL expression indicates that FasL(+) AM and AL (mainly Tc cells) comprise an important element of the fibrotic process, mostly in IPF. FasL might play a crucial role in other fibrosis-complicated ILDs, like NSIP and asbestosis.     

Microtubule heterogeneity of Ornithogalum umbellatum ovary epidermal cells: non-stable cortical microtubules and stable lipotubuloid microtubules

Lipotubuloids, structures containing lipid bodies and microtubules, are described in ovary epidermal cells of Ornithogalum umbellatum. Microtubules of lipotubuloids can be fixed in electron microscope fixative containing only buffered OsO(4) or in glutaraldehyde with OsO(4) post-fixation, or in a mixture of OsO(4) and glutaraldehyde. None of these substances fixes cortical microtubules of ovary epidermis of this plant which is characterized by dynamic longitudinal growth. However, cortical microtubules can be fixed with cold methanol according immunocytological methods with the use of β-tubulin antibodies and fluorescein. The existence of cortical microtubules has also been evidenced by EM observations solely after the use of taxol, microtubule stabilizer, and fixation in a glutaraldehyde/OsO(4) mixture. These microtubules mostly lie transversely, sometimes obliquely, and rarely parallel to the cell axis. Staining, using Ruthenium Red and silver hexamine, has revealed that lipotubuloid microtubules surface is covered with polysaccharides. The presumption has been made that the presence of a polysaccharide layer enhances the stability of lipotubuloid microtubules.     

Influence of myocardial infarction on changes in the expression of angiotensin type 1 receptor in the rat prostate

Angiotensin II (AngII) is the biologically active peptide of the renin-angiotensin system (RAS). Tissue- based, local RAS has been identified in the prostate, testis, epididymis and coagulating glands. Experimental and clinical studies have consistently shown that myocardial infarction (MI) is associated with activation of the systemic RAS with increased concentration of angiotensin peptides in the blood and changes in expression of angiotensin receptors (AT). Changes in angiotensin receptors in the renal and cardiovascular system after MI are well recognized, but the effects of MI influence on changes in other tissue like the prostate gland are unknown. In the present study, we investigated the effect of myocardial infarction on angiotensin receptor protein and mRNA expression in the rat prostate gland. MI model was established in Wistar rats by ligating the left coronary artery (modified Selye method). The levels of AT1a-b and AT2 receptor mRNAs and proteins were measured in the rat prostate. Our study demonstrates tissue-specific changes in AT1a-b and AT2 receptor expression after myocardial infarction. The results show that MI has a strong influence on the expression of angiotensin receptor type AT1 in the prostate at the protein and mRNA level.     

Identification by photoaffinity labeling of the extracellular N-terminal domain of PAC1 receptor as the major binding site for PACAP

Pituitary adenylate cyclase-activating polypeptide (PACAP) exerts many crucial biological functions through the interaction with its specific PAC1 receptor (PAC1-R), a class B G protein-coupled receptor (GPCR). To identify the binding sites of PACAP in the PAC1-R, three peptide derivatives containing a photoreactive p-benzoyl-phenylalanine (Bpa) residue were developed. These photosensitive PACAP analogs were fully biologically active and competent to displace radiolabeled Ac-PACAP27 from the PAC1-R. Subsequently, the ¹²⁵I-labeled photoprobes were used to anchor the PAC1-R expressed in Chinese hamster ovary cells. Photolabeling led to the formation of two protein complexes of 76 and 67 kDa, representing different glycosylated forms of the receptor. Proteinase and chemical cleavages of the peptide-receptor complexes revealed that ¹²⁵I[Bpa⁰, Nle¹⁷]PACAP27, ¹²⁵I[Bpa⁶, Nle¹⁷]PACAP27 and ¹²⁵I[Nle¹⁷, Bpa²²]PACAP27 covalently labeled the Ser⁹⁸ - Met¹¹¹ segment, the Ser¹²⁴ - Glu¹²⁵ dipeptide and the Ser¹⁴¹ - Met¹⁷² fragment, respectively. Taking into account the topology of the PAC1-R, these segments are mainly located within the extracellular N-terminal domain, indicating that this PAC1-R domain is the major binding site of PACAP27. The present study constitutes the first characterization of the binding domains of PACAP to its specific receptor and suggests heterogeneity within the binding mode of peptide ligands to class B GPCRs.