Interaction and circulation of symbolic goods in Quebrada de La Cueva, Jujuy, Argentina: The fossil Weyla alata (von Buch)

An Early Jurassic fossil bivalve specimen belonging to the pectinid genus Weyla was found within the low human occupation levels in a structure of Pukara de La Cueva, Humahuaca department, Jujuy province, Argentina. This is clearly a geologically allochthonous record, and its source should be located more than 400 km away, probably from a locality in the Main Cordillera of northern Chile or southern Perú. This evidence is part of a research project which analyzes the human interactions among the Quebrada de La Cueva sites and neighbouring productive regions, as well as the inferred interchange networks between this and other regions, both nearby and distant. In this context, the likely symbolic meaning of this record is also evaluated.     

Secretory cells in the foregut of the echinopluteus

Summary Metachromatically-staining substances have been found in the secretion of the stomodeum and esophagus of the echinopluteus (Psammechanus miliaris). This secretion seemed to derive from specialized cells in the wall of the foregut. Ultrastructural examination revealed that these cells are rich in large cisternae containing an electron-translucent material. They are also rich in ribosomes and possess large Golgi complexes. The number of secretory cells increases with age. It is tempting to speculate that the function of these cells is analogous to that of the glandular cells of the endostyle in some chordate phyla.     

ATM is involved in cell‐cycle control through the regulation of retinoblastoma protein phosphorylation

Ataxia telangiectasia mutated protein (ATM) is a member of the phosphatidylinositol‐3 kinase (PI3K) family, which has a role in the cellular response to DNA double‐strand breaks (DSBs). In the present study, we evaluated the role of ATM in cell‐cycle control in dopaminergic rat neuroblastoma B65 cells. For this purpose, ATM activity was either inhibited pharmacologically with the specific inhibitor KU‐55933, or the ATM gene was partially silenced by transfection with small interfering RNA (siRNA). Our data indicate that although ATM inhibition did not affect the cell cycle, both treatments specifically decreased the levels of cyclin A and retinoblastoma protein (pRb), phosphorylated at Ser780. Furthermore, ATM inhibition decreased the active form of p53, which is phosphorylated at Ser15, and also decreased Bax and p21 expression. Using H₂O₂ as a positive control of DSBs, caused a rapid pRb phosphorylation, this was prevented by KU‐55933 and siRNA treatment. Collectively, our data demonstrate how a new molecular network on ATM regulates the cell cycle through the control of pRb phosphorylation. These findings support a new target of ATM. J. Cell. Biochem. 110: 210–218, 2010. © 2010 Wiley‐Liss, Inc.     

Auxin metabolism in representative land PLANTS

The plant hormone auxin (indole-3-acetic acid, IAA) appears to control many plant developmental processes, and studies performed in seed plants suggest that IAA conjugation is the critical mechanism to regulate free IAA concentration. The purpose of this investigation is to characterize the biochemical ability of one charophyte and 23 land plants ranging from liverworts to angiosperms to produce IAA conjugates, and to study the complexity of their conjugation patterns. Actively growing tissue was incubated with ¹⁴C-IAA, after which labeled IAA conjugates were separated using thin-layer chromatography. The conjugates were analyzed using radioimaging techniques and their tentative identity assigned by co-chromatography and/or by differential hydrolysis. The charophyte and the liverworts appear unable to conjugate IAA. The mosses and the hornwort are able to conjugate IAA into a few amide and ester conjugates. The tracheophytes examined synthesize several conjugates unique to the vascular plants, indole-3-acetyl-aspartic acid (-glutamic acid) and/or indole-3-acetyl-β-1-O-glucose, as well as a variety of other amide and ester conjugates. These three conjugation patterns are correlated to the type of conducting tissue characteristic of the plants analyzed. These biochemical differences may be indicative of significative differences in the hormonal regulation in these plant groups, thus suggesting that changes in IAA regulation accompanied the major evolutionary events in land plants.     

Defective endoplasmic reticulum-mitochondria contacts and bioenergetics in SEPN1-related myopathy

SEPN1-related myopathy (SEPN1-RM) is a muscle disorder due to mutations of the SEPN1 gene, which is characterized by muscle weakness and fatigue leading to scoliosis and life-threatening respiratory failure. Core lesions, focal areas of mitochondria depletion in skeletal muscle fibers, are the most common histopathological lesion. SEPN1-RM underlying mechanisms and the precise role of SEPN1 in muscle remained incompletely understood, hindering the development of biomarkers and therapies for this untreatable disease. To investigate the pathophysiological pathways in SEPN1-RM, we performed metabolic studies, calcium and ATP measurements, super-resolution and electron microscopy on in vivo and in vitro models of SEPN1 deficiency as well as muscle biopsies from SEPN1-RM patients. Mouse models of SEPN1 deficiency showed marked alterations in mitochondrial physiology and energy metabolism, suggesting that SEPN1 controls mitochondrial bioenergetics. Moreover, we found that SEPN1 was enriched at the mitochondria-associated membranes (MAM), and was needed for calcium transients between ER and mitochondria, as well as for the integrity of ER-mitochondria contacts. Consistently, loss of SEPN1 in patients was associated with alterations in body composition which correlated with the severity of muscle weakness, and with impaired ER-mitochondria contacts and low ATP levels. Our results indicate a role of SEPN1 as a novel MAM protein involved in mitochondrial bioenergetics. They also identify a systemic bioenergetic component in SEPN1-RM and establish mitochondria as a novel therapeutic target. This role of SEPN1 contributes to explain the fatigue and core lesions in skeletal muscle as well as the body composition abnormalities identified as part of the SEPN1-RM phenotype. Finally, these results point out to an unrecognized interplay between mitochondrial bioenergetics and ER homeostasis in skeletal muscle. They could therefore pave the way to the identification of biomarkers and therapeutic drugs for SEPN1-RM and for other disorders in which muscle ER-mitochondria cross-talk are impaired.Subject terms: Chaperones, Respiratory tract diseases     

Correlation between timed up and go test and skeletal muscle tensiomyography in female nursing home residents

Objectives:Tensiomyography (TMG) derived contraction time (Tc) and amplitude (Dm) are related to muscle fibre composition and to muscle atrophy/tone, respectively. However, the link between mobility and TMG-derived skeletal muscle contractile properties in older persons is unknown. The aim of the study was to correlate lower limb skeletal muscle contractile properties with balance and mobility measures in senior female residents of retirement homes in Austria.Methods:Twenty-eight female participants (aged from 67-99 years) were included in measurements of contractile properties (TMG) of four skeletal muscles: vastus lateralis, vastus medialis, biceps femoris and gastrocnemius medialis. Their balance and mobility performance was measured using a timed up and go test (TUG).Results:Time needed to complete TUG is negatively correlated to biceps femoris (r= -0.490; p= 0.008), vastus lateralis (r= -0.414; p=0.028) and vastus medialis (r= -0.353; p=0.066) Dm and positively correlated to vastus lateralis Tc (r=0.456; p=0.015). Overall, vastus lateralis Tc and vastus medialis Dm explained 37% of TUG time variance.Conclusions:Our study demonstrates that TMG-derived quadriceps muscle contractile parameters are correlated with the balance and mobility function in female nursing home residents.