trans-Activation of the human T-cell leukemia virus long terminal repeat correlates with expression of the x-lor protein.

Cell lines established directly from adult T-cell leukemia-lymphoma patients or immortalized by human T-cell leukemia virus type I (HTLV-I) in vitro that do not produce complete HTLV virions were characterized both for the content of viral proteins and for the presence of trans-acting factors activating gene expression under the control of the HTLV long terminal repeat. The expression of the 42-kilodalton HTLV x-lor product correlated with trans-activation of the long terminal repeat. The implications of this study for understanding the role of the HTLV x-lor product in the initiation and maintenance of T-lymphocyte transformation are discussed.     

Intestinal cell types in the freshwater snail planorbarius corneus: Histochemical, immunocytochemical and ultrastructural observations

The intestinal cell types of the pulmonate gastropodPlanorbarius corneus were studied using histochemical, immunocytochemical and ultrastructural procedures. Supporting cells, mucous cells and gland cells were observed in the intestine epithelium. The supporting cells seem to be involved in absorption process, showing endocytosis vesicles, evidence of lysosomal activity and storage of reserve materials. The presence of epithelial cells specialized in secretion indicates that digestive enzymes may be produced. Indeed, immunoreactive alpha-amylase molecules have been demonstrated. Some gland cells showed the ultrastructural features of invertebrate and vertebrate enteroendocrine cells and were also positive to vertebrate anti-insulin, anti-gastrin and anti-serotonin antibodies.     

Interspecies transmission of macaque simian T-cell leukemia/lymphoma virus type 1 in baboons resulted in an outbreak of malignant lymphoma.

An outbreak of malignant lymphoma has been observed in one of the baboon (Papio hamadryas) stocks of Sukhumi Primate Center. More than 300 cases in this "high-lymphoma stock" have been registered since 1967. Human T-cell lymphotropic virus type 1 (HTLV-1)-related virus was implicated as the etiologic agent of Sukhumi baboon lymphoma. The origin of this virus remained unclear. Two possibilities were originally considered: the origin could be baboon simian T-cell leukemia/lymphoma virus type 1 (STLV-1) or HTLV-1 (before the outbreak started, some Sukhumi baboons were inoculated with human leukemic material). The third possibility entered recently: interspecies transmission of rhesus macaque STLV-1 to baboons. It was prompted by the finding of very close similarity between STLV-1 991-1cc (the strain isolated from a non-Sukhumi baboon inoculated with material from a Sukhumi lymphomatous baboon) and rhesus STLV-1. To test this hypothesis, we investigated 37 Sukhumi STLV-1 isolates from baboons of high-lymphoma stock by PCR discriminating rhesus type and baboon type STLV-1 isolates. All of them were proved to be rhesus type STLV-1. In contrast, all six STLV-1 isolates from baboons belonging to other stocks or populations were of baboon type. The PCR results were fully confirmed by DNA sequence data. The partial env gene gene sequences of all four STLV-1 isolates from Sukhumi lymphomatous baboons were 97 to 100% similar to the sequence of known rhesus STLV-1 and only 85% homologous with the sequence of conventional baboon STLV-1. Thus, interspecies transmission of STLV-1 from rhesus macaques (or closely related species) to baboons occurred at Sukhumi Primate Center. Most probably this event initiated the outbreak of lymphoma in Sukhumi baboons.     

The digestive gland of Viviparus ater (Mollusca, Gastropoda, Prosobranchia): an ultrastructural and histochemical study

The digestive gland of Viviparus ater was studied using histochemical and ultrastructural methods. Only one cell type was observed in the tubule epithelium of the gland. The cells are involved in an endocytotic process mediated by clathrin-coated vesicles and in the intracellular digestion of food materials (thus they can be regarded as digestive cells). The different stages of digestion and exocytotic extrusion of residual bodies into the tubule lumen were shown by electron microscopy. Very few, small mucocytes are scattered among the digestive cells. Calcium concretions, glycogen-containing cells and endocrine cells are scattered in the area of connective tissue present among the digestive tubules.     

Intragenic duplication and divergence in the spectrin superfamily of proteins

Many structural, signaling, and adhesion molecules contain tandemly repeated amino acid motifs. The alpha-actinin/spectrin/dystrophin superfamily of F-actin-crosslinking proteins contains an array of triple alpha-helical motifs (spectrin repeats). We present here the complete sequence of the novel beta-spectrin isoform beta(Heavy)- spectrin (beta H). The sequence of beta H supports the origin of alpha- and beta-spectrins from a common ancestor, and we present a novel model for the origin of the spectrins from a homodimeric actin-crosslinking precursor. The pattern of similarity between the spectrin repeat units indicates that they have evolved by a series of nested, nonuniform duplications. Furthermore, the spectrins and dystrophins clearly have common ancestry, yet the repeat unit is of a different length in each family. Together, these observations suggest a dynamic period of increase in repeat number accompanied by homogenization within each array by concerted evolution. However, today, there is greater similarity of homologous repeats between species than there is across repeats within species, suggesting that concerted evolution ceased some time before the arthropod/vertebrate split. We propose a two-phase model for the evolution of the spectrin repeat arrays in which an initial phase of concerted evolution is subsequently retarded as each new protein becomes constrained to a specific length and the repeats diverge at the DNA level. This evolutionary model has general applicability to the origins of the many other proteins that have tandemly repeated motifs.      

Higher‐order assemblies of oligomeric cargo receptor complexes form the membrane scaffold of the Cvt vesicle

Selective autophagy is the mechanism by which large cargos are specifically sequestered for degradation. The structural details of cargo and receptor assembly giving rise to autophagic vesicles remain to be elucidated. We utilize the yeast cytoplasm‐to‐vacuole targeting (Cvt) pathway, a prototype of selective autophagy, together with a multi‐scale analysis approach to study the molecular structure of Cvt vesicles. We report the oligomeric nature of the major Cvt cargo Ape1 with a combined 2.8 Å X‐ray and negative stain EM structure, as well as the secondary cargo Ams1 with a 6.3 Å cryo‐EM structure. We show that the major dodecameric cargo prApe1 exhibits a tendency to form higher‐order chain structures that are broken upon interaction with the receptor Atg19 in vitro. The stoichiometry of these cargo–receptor complexes is key to maintaining the size of the Cvt aggregate in vivo. Using correlative light and electron microscopy, we further visualize key stages of Cvt vesicle biogenesis. Our findings suggest that Atg19 interaction limits Ape1 aggregate size while serving as a vehicle for vacuolar delivery of tetrameric Ams1.     

The Effects of Hyperbaric Oxygen Therapy on Post-Training Recovery in Jiu-Jitsu Athletes

Objectives

The present study aimed to evaluate the effects of using hyperbaric oxygen therapy during post-training recovery in jiu-jitsu athletes.

Methods

Eleven experienced Brazilian jiu-jitsu athletes were investigated during and following two training sessions of 1h30min. Using a cross-over design, the athletes were randomly assigned to passive recovery for 2 hours or to hyperbaric oxygen therapy (OHB) for the same duration. After a 7-day period, the interventions were reversed. Before, immediately after, post 2 hours and post 24 hours, blood samples were collected to examine hormone concentrations (cortisol and total testosterone) and cellular damage markers [creatine kinase (CK), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH)]. Moreover, the rating of perceived exertion (RPE) and recovery (RPR) scales were applied.

Results

Final lactate [La] values (control: 11.9 ± 1.4 mmol/L, OHB: 10.2 ± 1.4 mmol/L) and RPE [control: 14 (13–17 a.u.), OHB: 18 (17–20 a.u.)] were not significantly different following the training sessions. Furthermore, there was no difference between any time points for blood lactate and RPE in the two experimental conditions (P>0.05). There was no effect of experimental conditions on cortisol (F_1,20 = 0.1, P = 0.793, η² = 0.00, small), total testosterone (F_1,20 = 0.03, P = 0.877, η² = 0.00, small), CK (F_1,20 = 0.1, P = 0.759, η² = 0.01, small), AST (F_1,20 = 0.1, P = 0.761, η² = 0.01, small), ALT (F_1,20 = 0.0, P = 0.845, η² = 0.00, small) or LDH (F_1,20 = 0.7, P = 0.413, η² = 0.03, small). However, there was a difference between the two experimental conditions in RPR with higher values at post 2 h and 24 h in OHB when compared to the control condition (P<0.05).

Conclusions

Thus, it can be concluded that OHB exerts no influence on the recovery of hormonal status or cellular damage markers. Nonetheless, greater perceived recovery, potentially due to the placebo effect, was evident following the OHB condition.     

Endothelial cell junctions

In the course of a freeze-cleave study on intercellular junctions in the regenerating rat liver, we observed an unusual array of intramembranous particles located in regions of contact between endothelial cells lining the hepatic sinusoids. These arrays were characterized by an accumulation of particles which resembled a zonula occludens in their linear deployment but differed in that the contact regions were composed of individual particles which remained separated from each other by regular particle-free intervals.     

Characterization of glycoconjugates in an embryonic human epithelial line and changes consequent to adaptation to a hyperosmotic medium

Summary Cell surface and cytoplasmic glycoconjugates were characterized in embryonic human explant cells (a transformed heteroploid line) cultured in iso-osmotic medium (0.137m NaCl) and in hyperosmotic medium (0.274m NaCl) for 10 days in order to study the changes induced in these compounds by hyperosmoticity. Cytochemical and ultracytochemical staining selective for glycoconjugates was carried out. The following results were obtained: (1) glycoproteins, glycosaminoglycans and glycolipids are present on the cell surface and in the cytoplasm of the explant cells; (2) lectin histochemistry combined with glycosidase digestion demonstrated the presence of the disaccharides fucose-N-acetylglucosamine and sialic acid--galactose as terminal sequences; (3) histophotometric evaluation of lectin labelling showed a noticeable decrease in histochemical reactivity of adapted cells; (4) plasma membrane cell coat decreased in adapted cells, which was emphasized by ultracytochemical reactions and a rearrangement of glycolipids in the cytoplasm.