Granular “endocrine” cells in avian respiratory epithelia

Summary An electron microscopic investigation of the extrapulmonary respiratory tract of embryos and chick of the domestic fowl (Gallus domesticus) has demonstrated for the first time in birds the presence here of a small number of epithelial cells characterised by an aminecontaining type of granule. These granular cells were scattered singly throughout the trachea, syrinx and primary bronchi and seemed more numerous in the caudal part of the airway. In favourable planes of section a small part of the cell was in contact with the luminal surface of the epithelium. The characteristic granular vesicles (approximate diameter 140 nm) appeared to be randomly distributed in the cytoplasm and there was no concentration of vesicles close to the plasma membrane. One of the cells was closely associated with an intraepithelial axon. By fluorescence microscopy, a small number of cells with a similar shape and distribution to the granular cells was observed after administration of 3,4-dihydroxyphenylalanine which may indicate the presence of an amine handlign mechanism in these cells. It is suggested that the granular cells belong to the APUD system of endocrine cells and that they may be modulated by the concentration of gas in the airways.     

Isolation and characterization of plasma membrane-associated cortical granules from sea urchin eggs

Cortical granules, which are specialized secretory organelles found in ova of many organisms, have been isolated from the eggs of the sea urchins Arbacia punctulata and Strongylocentrtus pupuratus by a simple, rapid procedure. Electron micropscope examination of cortical granules prepared by this procedure reveals that they are tightly attached to large segments of the plasma membrane and its associated vitelline layer. Further evidence that he cortical granules were associated with these cell surface layers was obtained by (125)I-labeling techniques. The cortical granule preparations were found to be rich in proteoesterase, which was purified 32-fold over that detected in a crude homogenate. Similarly, the specific radioactivity of a (125)I-labeled, surface glycoprotein was increased 40-fold. These facts, coupled with electron microscope observations, indicate the isolation procedure yields a preparation in which both the cortical granules and the plasma membrane-vitelline layer are purified to the same extent. Gel electrophoresis of the membrane-associated cortical granule preparation reveals the presence of at least eight polypeptides. The major polypeptide, which is a glycotprotein of apparent mol wt of 100,000, contains most of the radioactivity introduced by (125)I-labeling of the intact eggs. Lysis of the cortical granules is observed under hypotonic conditions, or under isotonic conditions if Ca(2+) ion is present. When lysis is under isotonic conditions is induced by addition of Ca(2+) ion, the electron-dense contents of the granules remain insoluble. In contrast, hypotonic lysis results in release of the contents of the granule in a soluble form. However, in both cases the (125)I-labeled glycoprotein remains insoluble, presumably because it is a component of either the plasma membrane or the vitelline layer. All these findings indicate that, using this purified preparation, it should be possible to carry out in vitro studies to better define some of the initial, surface-related events observed in vivo upon fertilization.     

Phylogenetic utility of the nuclear gene arginine decarboxylase: an example from Brassicaceae

Arginine decarboxylase (ADC) is an important enzyme in the production of putrescine and polyamines in plants. It is encoded by a single or low-copy nuclear gene that lacks introns in sequences studied to date. The rate of Adc amino acid sequence evolution is similar to that of ndhF for the angiosperm family studied. Highly conserved regions provide several target sites for PCR priming and sequencing and aid in nucleotide and amino acid sequence alignment across a range of taxonomic levels, while a variable region provides an increased number of potentially informative characters relative to ndhF for the taxa surveyed. The utility of the Adc gene in plant molecular systematic studies is demonstrated by analysis of its partial nucleotide sequences obtained from 13 representatives of Brassicaceae and 3 outgroup taxa, 2 from the mustard oil clade (order Capparales) and 1 from the related order Malvales. Two copies of the Adc gene, Adc1 and Adc2, are found in all members of the Brassicaceae studied to data except the basal genus Aethionema. The resulting Adc gene tree provides robust phylogenetic data regarding relationships within the complex mustard family, as well as independent support for proposed tribal realignments based on other molecular data sets such as those from chloroplast DNA.      

Effects of aerobic exercise therapy and cognitive behavioural therapy on functioning and quality of life in amyotrophic lateral sclerosis: protocol of the FACTS-2-ALS trial

Background

Neuropathic pain must be correctly diagnosed for optimal treatment. The questionnaire named Neuropathic Pain Symptom Inventory (NPSI) was developed in its original French version to evaluate the different symptoms of neuropathic pain. We hypothesized that the NPSI might also be used to differentiate neuropathic from non-neuropathic pain.

Methods

We translated the NPSI into German using a standard forward-backward translation and administered it in a case-control design to patients with neuropathic (n = 68) and non-neuropathic pain (headache and osteoarthritis, n = 169) to validate it and to analyze its discriminant properties, its sensitivity to change, and to detect neuropathic pain subgroups with distinct profiles.

Results

Using a sum score (the NPSI-G score), we found sensitivity to change (r between 0.37 and 0.5 for pain items of the graded chronic pain scale) and could distinguish between neuropathic and other pain on a group basis, but not for individual patients. Post hoc development of a discriminant score with optimized diagnostic properties to distinguish neuropathic pain from non-neuropathic pain resulted in an instrument with high sensitivity (91%) and acceptable specificity (70%). We detected six different pain profiles in the patient group with neuropathic pain; three profiles were found to be distinct.

Conclusions

The NPSI-G potentially combines the properties of a diagnostic tool and an instrument to identify subtypes of neuropathic pain.     

MFN2 retrotranslocation boosts mitophagy by uncoupling mitochondria from the ER

Mitochondrial damage triggers mitochondrial quality control pathways, which act to ensure the health of the mitochondrial network. The turnover of damaged mitochondria by mitophagy is initiated by the Parkinson disease-linked genes PRKN and PINK1, and we recently investigated the role that interorganellar contact sites between the endoplasmic reticulum (ER) and the outer mitochondrial membrane (OMM) play in this pathway. In this punctum, we summarize our findings that show that the ER-OMM tether MFN2 acts as a suppressor of mitophagy through its ability to link the OMM to the ER, potentially limiting the accessibility of other ubiquitination substrates to PINK1 and PRKN. PINK1, PRKN and the AAA-ATPase VCP disrupt contact between mitochondria and the ER via MFN2 ubiquitination, retrotranslocation and turnover from the mitochondrial membrane. Our study provides insight into the role of OMM remodeling in mitophagy.     

Pathologic and hematologic responses to surgically implanted transmitters in eastern massasauga rattlesnakes (Sistrurus catenatus catenatus)

The study of secretive snakes, such as rattlesnakes, has benefited from the use of radiotelemetry. However, the principal assumption in telemetry studies is that the transmitter has no significant effect on the study animal. To test the validity of this assumption, the physiologic and pathologic effects of intracoelomic implants were examined in a group of 24 eastern massasauga rattlesnakes (Sistrurus catenatus catenatus) in a laboratory setting over a period of 58 wk between March 2005 and April 2006. Inflammation and infection were evaluated using gross examination, histopathology, bacteriology, hematology, and plasma protein electrophoresis. Inflammation and infection occurred despite careful surgical procedures and advanced veterinary care. Four of 12 (33%) snakes developed extensive inflammatory response to the transmitter and associated anaerobic and gram-negative bacterial infections. Another four (33%) snakes showed mild inflammatory responses without infection. Reaction to the transmitters was reflected in changes in values for heterophils, monocytes, alpha-1, and beta globulin levels. Some conclusions reached in field studies using implanted radiotransmitters in snakes may be invalid if the implant influences the behavior or survival of the subject. Advances in attachment methods and transmitter coating technology may prevent some of the adverse effects associated with surgically implanted transmitters.     

Chromosome numbers and meiotic analysis in the pre-breeding of <Emphasis Type="BoldItalic">Brachiaria decumbens</Emphasis> (Poaceae)

A total of 44 accessions of Brachiaria decumbens were analysed for chromosome count and meiotic behaviour in order to identify potential progenitors for crosses. Among them, 15 accessions presented 2n = 18; 27 accessions, 2n = 36; and 2 accessions, 2n = 45 chromosomes. Among the diploid accessions, the rate of meiotic abnormalities was low, ranging from 0.82% to 7.93%. In the 27 tetraploid accessions, the rate of meiotic abnormalities ranged from 18.41% to 65.83%. The most common meiotic abnormalities were related to irregular chromosome segregation, but chromosome stickiness and abnormal cytokinesis were observed in low frequency. All abnormalities can compromise pollen viability by generating unbalanced gametes. Based on the chromosome number and meiotic stability, the present study indicates the apomictic tetraploid accessions that can act as male genitor to produce interspecific hybrids with B. ruziziensis or intraspecific hybrids with recently artificially tetraploidized accessions.     

USP8 regulates mitophagy by removing K6‐linked ubiquitin conjugates from parkin

Mutations in the Park2 gene, encoding the E3 ubiquitin‐ligase parkin, are responsible for a familial form of Parkinson's disease (PD). Parkin‐mediated ubiquitination is critical for the efficient elimination of depolarized dysfunctional mitochondria by autophagy (mitophagy). As damaged mitochondria are a major source of toxic reactive oxygen species within the cell, this pathway is believed to be highly relevant to the pathogenesis of PD. Little is known about how parkin‐mediated ubiquitination is regulated during mitophagy or about the nature of the ubiquitin conjugates involved. We report here that USP8/UBPY, a deubiquitinating enzyme not previously implicated in mitochondrial quality control, is critical for parkin‐mediated mitophagy. USP8 preferentially removes non‐canonical K6‐linked ubiquitin chains from parkin, a process required for the efficient recruitment of parkin to depolarized mitochondria and for their subsequent elimination by mitophagy. This work uncovers a novel role for USP8‐mediated deubiquitination of K6‐linked ubiquitin conjugates from parkin in mitochondrial quality control.