Changes in cytoplasmic and lysosomal enzyme activities in cultured rat heart cells: The relationship to cell differentiation and cell population in culture

Summary Postnatal rat heart cells in culture enriched with respect to muscle cells were obtained by either high density seeding or by the replating technique. [³H]Thymidine incorporation to DNA and the enzymatic pattern of cytoplasmic and lysosomal enzymes have been studied as a function of the culture’s age, of seeding density, and replating. It was shown that (a) replating maintains predominance of myocyte population for at least 2 wk in culture; (b) heavy seeding density allows homogeneous myocyte population for the 1st wk in culture; and (c) the enzyme profile of the culture may serve as an indicator for the type of cell population in culture and its state of differentiation. This study was done as partial fulfilment of the M.Sc. thesis in Biochemistry (SY). Supported by grants from The Chief Scientist, Ministry of Health, State of Israel; The Ministry of Education and Sciences, State of Niedersachssen (FRG); and The Foundation for Heart Research from Mr. and Mrs. D. Vidal-Madjar, Paris, France.     

The pineal gland of the mole-rat (Spalax ehrenbergi,Nehring)

Summary A comparative investigation of the distribution of monoaminergic neurons in non-malacostracan crustaceans was performed with the histochemical fluorescence method of Falck-Hillarp.Two fluorophores were found: the more widespread of the two emits a green fluorescence; and the more sparsely distributed emits a yellow to brown-yellow fluorescence.Specific green fluorescent areas were shown to exist in the protocerebrum. The central body and the optic ganglia of the compound eye (where present) are always fluorescent. Moreover, the centre of the nauplius eye may have a green fluorophore, as in ostracods, and a neuropile area, here called the frontal area. These neuropile centres are known from ordinary histological studies of the nervous system. In addition, there are specific monoaminergic centres, such as the so-called dorsal area of phyllopods and anostracans as well as the copepod specific areas. Specific monoaminergic areas appear in the deutocerebrum and the suboesophageal ganglion where they are particularly well developed.Presumed sensory neurons in the cavity receptor organ of Artemia salina are shown to be monoaminergic. Monoaminergic sensory neurons have not been described previously in Arthropods.Presumed motor innervation of hind-gut and trunk muscles is also found, and it is concluded that in crustaceans neurons of every type (sensory, internuncial, motor) may be monoaminergic.We have enjoyed unrestricted laboratory facilities at the Department of Histology, Faculty of Medicine, and with great pleasure express our sincere thanks to Prof. Bengt Falck. — Grants from the Swedish Natural Science Research Council (2760-007), the Swedish Medical Research Council (04X-712), the Royal Swedish Academy of Science (Hierta-Retzius), the Royal Physiographic Society of Lund, and the University of Lund supported the work.     

Protein kinase C (PKC) level is increased in PC12 cells overexpressing transfected liver-type phosphofructokinase

Summary— PC12 cells which overexpress transfected liver-type phosphofructokinase (PFKL) have previously been described as a model system for PFKL overexpression in Down's syndrome and have been shown to perform glycolysis at enhanced rates. Here we report that levels of protein kinase C (PKC) in PC 12-PFKL cells were almost doubled, as estimated from in vitro activity and phorbol ester binding experiments and from an increase found in PKC-alpha mRNA levels. Most of the added PKC was found to be associated with the cellular membrane while the cytoplasmic levels of PKC were barely increased. The steady-state levels of 1,2-sn-diacylglycerol in PC12-PFKL cells were found to be unaltered, suggesting that enhanced glycolysis in these cells did not influence PKC by altering the amounts of this compound. PFKL is one of several genes known to be overexpressed in Down's syndrome. Upregulation of PKC due to PFKL overexpression could result in widespread disturbances of gene expression and play a part in causing some of the many symptoms of the disease.     

Mixed company: a framework for understanding the composition and organization of mixed‐species animal groups

Mixed‐species animal groups (MSGs) are widely acknowledged to increase predator avoidance and foraging efficiency, among other benefits, and thereby increase participants' fitness. Diversity in MSG composition ranges from two to 70 species of very similar or completely different phenotypes. Yet consistency in organization is also observable in that one or a few species usually have disproportionate importance for MSG formation and/or maintenance. We propose a two‐dimensional framework for understanding this diversity and consistency, concentrating on the types of interactions possible between two individuals, usually of different species. One axis represents the similarity of benefit types traded between the individuals, while the second axis expresses asymmetry in the relative amount of benefits/costs accrued. Considering benefit types, one extreme represents the case of single‐species groups wherein all individuals obtain the same supplementary, group‐size‐related benefits, and the other extreme comprises associations of very different, but complementary species (e.g. one partner creates access to food while the other provides vigilance). The relevance of social information and the matching of activities (e.g. speed of movement) are highest for relationships on the supplementary side of this axis, but so is competition; relationships between species will occur at points along this gradient where the benefits outweigh the costs. Considering benefit amounts given or received, extreme asymmetry occurs when one species is exclusively a benefit provider and the other a benefit user. Within this parameter space, some MSG systems are constrained to one kind of interaction, such as shoals of fish of similar species or leader–follower interactions in fish and other taxa. Other MSGs, such as terrestrial bird flocks, can simultaneously include a variety of supplementary and complementary interactions. We review the benefits that species obtain across the diversity of MSG types, and argue that the degree and nature of asymmetry between benefit providers and users should be measured and not just assumed. We then discuss evolutionary shifts in MSG types, focusing on drivers towards similarity in group composition, and selection on benefit providers to enhance the benefits they can receive from other species. Finally, we conclude by considering how individual and collective behaviour in MSGs may influence both the structure and processes of communities.     

Ptr1 evolved convergently with RPS2 and Mr5 to mediate recognition of AvrRpt2 in diverse solanaceous species

The Ptr1 (Pseudomonas tomato race 1) locus in Solanum lycopersicoides confers resistance to strains of Pseudomonas syringae pv. tomato expressing AvrRpt2 and Ralstonia pseudosolanacearum expressing RipBN. Here we describe the identification and phylogenetic analysis of the Ptr1 gene. A single recombinant among 585 F2 plants segregating for the Ptr1 locus was discovered that narrowed the Ptr1 candidates to eight nucleotide‐binding leucine‐rich repeat protein (NLR)‐encoding genes. From analysis of the gene models in the S. lycopersicoides genome sequence and RNA‐Seq data, two of the eight genes emerged as the strongest candidates for Ptr1. One of these two candidates was found to encode Ptr1 based on its ability to mediate recognition of AvrRpt2 and RipBN when it was transiently expressed with these effectors in leaves of Nicotiana glutinosa. The ortholog of Ptr1 in tomato and in Solanum pennellii is a pseudogene. However, a functional Ptr1 ortholog exists in Nicotiana benthamiana and potato, and both mediate recognition of AvrRpt2 and RipBN. In apple and Arabidopsis, recognition of AvrRpt2 is mediated by the Mr5 and RPS2 proteins, respectively. Phylogenetic analysis places Ptr1 in a distinct clade compared with Mr5 and RPS2, and it therefore appears to have arisen by convergent evolution for recognition of AvrRpt2.     

Phytoremediation of 1,4-Dioxane-Containing Recovered Groundwater

The results of a pilot-scale phytoremediation study are reported in this paper. Small plots of trees established on a closed municipal waste landfill site were irrigated with recovered groundwater containing 1,4-dioxane (dioxane) and other volatile organic compounds (VOCs). The plots were managed to minimize the leaching of irrigation water, and leaching was quantified by the use of bromide tracer. Results indicated that the dioxane (2.5 μg/L) was effectively removed, probably via phytovolatilization, and that a full-scale phytoremediation system could be used. A system is now in place at the site in which the recovered groundwater can be treated using two different approaches. A physical treatment system (PTS) will be used during the winter months, and a 12 ha phytoremediation system (stands of coniferous trees) will be used during the growing season. The PTS removes VOCs using an air-stripper, and destroys dioxane using a photo-catalytic oxidation process. Treated water will be routed to the local sewer system. The phytoremediation system, located on the landfill, will be irrigated with effluent from the PTS air-stripper containing dioxane. Seasonal use of the phytoremediation system will reduce reliance on the photo-catalytic oxidation process that is extremely energy consumptive and expensive to operate.     

CYP1A1 genetic polymorphisms,tobacco smoking and lung cancer risk in a French Caucasian population

The CYP1A1 gene encoding for an enzyme involved in the metabolic activation of important tobacco carcinogens could be implicated in smoking-induced lung cancer. Given the strong association between tobacco smoking and lung cancer, the effect of tobacco smoke exposure has to be taken into account when studying the potential association between lung cancer and CYP1A1 genotypes. The effect of two CYP1A1 genetic polymorphisms (Mspl and IIe-Val) on lung cancer risk were evaluated using peripheral blood DNA from 150 lung cancer patients and 171 controls. The Mspl sitepresent allele was found among 19.3% of both cases and controls and the variant allele Val among 6.7% of cases and 8.8% of controls. Lung cancer risks associated with the Mspl site-present allele (OR= 0.9; 95%Cl: 0.5-1.8) or with the Val allele (OR= 0.8; 95%Cl: 0.3-1.9) were not increased after adjustment for tobacco and asbestos exposures. These results persisted when analyses were stratified on smoking status, daily consumption of tobacco or duration of smoking. Similar findings were obtained when squamous cell or small cell carcinomas were studied separately. This study thus suggests a minor role for the known CYP1A1 gene polymorphisms in predisposition to lung cancer among Caucasian populations.     

Induction of heat shock proteins in cerebral cortical cultures by celastrol

Alzheimer’s disease, Parkinson’s disease and amyotrophic lateral sclerosis (ALS) are ‘protein misfolding disorders’ of the mature nervous system that are characterized by the accumulation of protein aggregates and selective cell loss. Different brain regions are impacted, with Alzheimer’s affecting cells in the cerebral cortex, Parkinson’s targeting dopaminergic cells in the substantia nigra and ALS causing degeneration of cells in the spinal cord. These diseases differ widely in frequency in the human population. Alzheimer’s is more frequent than Parkinson’s and ALS. Heat shock proteins (Hsps) are ‘protein repair agents’ that provide a line of defense against misfolded, aggregation-prone proteins. We have suggested that differing levels of constitutively expressed Hsps (Hsc70 and Hsp27) in neural cell populations confer a variable buffering capacity against ‘protein misfolding disorders’ that correlates with the relative frequencies of these neurodegenerative diseases. The high relative frequency of Alzheimer’s may due to low levels of Hsc70 and Hsp27 in affected cell populations that results in a reduced defense capacity against protein misfolding. Here, we demonstrate that celastrol, but not classical heat shock treatment, is effective in inducing a set of neuroprotective Hsps in cultures derived from cerebral cortices, including Hsp70, Hsp27 and Hsp32. This set of Hsps is induced by celastrol at ‘days in vitro’ (DIV) 13 when cultured cortical cells reached maturity. The inducibility of a set of neuroprotective Hsps in mature cortical cultures at DIV13 suggests that celastrol is a potential agent to counter Alzheimer’s disease, a neurodegenerative ‘protein misfolding disorder’ of the adult brain that targets cells in the cerebral cortex.