Biological mechanisms of aging predict age‐related disease co‐occurrence in patients

Genetic, environmental, and pharmacological interventions into the aging process can confer resistance to multiple age‐related diseases in laboratory animals, including rhesus monkeys. These findings imply that individual mechanisms of aging might contribute to the co‐occurrence of age‐related diseases in humans and could be targeted to prevent these conditions simultaneously. To address this question, we text mined 917,645 literature abstracts followed by manual curation and found strong, non‐random associations between age‐related diseases and aging mechanisms in humans, confirmed by gene set enrichment analysis of GWAS data. Integration of these associations with clinical data from 3.01 million patients showed that age‐related diseases associated with each of five aging mechanisms were more likely than chance to be present together in patients. Genetic evidence revealed that innate and adaptive immunity, the intrinsic apoptotic signaling pathway and activity of the ERK1/2 pathway were associated with multiple aging mechanisms and diverse age‐related diseases. Mechanisms of aging hence contribute both together and individually to age‐related disease co‐occurrence in humans and could potentially be targeted accordingly to prevent multimorbidity.     

Flight potential and oxygen uptake during early dormancy in Coccinella septempunctata

Two flight parameters (take-off and duration) and respiration level were measured, in two years in summer and early autumn, in dormant Coccinella septempunctata L. (Coleoptera: Coccinellidae) collected while hidden in grass tussocks in hibernation sites (HID) and in beetles collected on plants (PLA). The duration of tethered flight of HID beetles measured in the laboratory in late August and September 1995 (range of geometric means 190–440 s) was slightly longer than the flight of PLA beetles (80–310 s), both being much longer than trivial flight recorded in beetles foraging for prey during the breeding season (35 s). In general, the flight performance had a tendency to increase in September and to decrease in October.The oxygen consumption in HID beetles increased throughout September 1994 from 430 to 780 l g^–1 h^–1 and throughout October 1995 from 710 to 1060 l g^–1 h^–1. This increase is ascribed to a concomitant decrease in diapause intensity. A similar increase was observed also in PLA beetles in 1994 and oxygen consumption was always higher than in HID beetles, most probably due to feeding and digestion in PLA beetles.Laboratory feeding of HID beetles on aphids induced maturation of ovaries and increased oxygen uptake (from 680 to 1110 l g^–1 h^–1). Feeding on honey and pollen left their oxygen uptake unchanged. Effect of feeding on the flight parameters was mostly not significant. In agreement with its less suitable body shape and usually less distant dormancy sites, C. septempunctata was found a less apt flier than long-distance migrating coccinellid species.     

AMP-deaminase from normal and cirrhotic human liver: A comparative study

AMP-deaminase (EC 3.5.4.6) is an enzyme of nucleotide breakdown involved in regulation of adenine nucleotide pool in mammalian cells. Reaction catalysed by AMP-deaminase constitutes a rate-limiting step in adenine nucleotide catabolism in liver. In this study kinetic and regulatory properties of AMP-deaminase purified from normal and cirrhotic human liver were investigated. In comparison to AMP-deaminase extracted from the normal human liver, AMP-deaminase extracted from the cirrhotic liver was less sensitive towards substrate analogues, and only a very limited response towards pH and adenylate energy charge changes tested for enzyme isolated from this tissue source had been observed. At physiological pH 7.0, in the absence and in the presence of important allosteric effectors (ATP, ADP, GTP and orthophosphate), AMP-deaminases from the two sources studied manifested different regulatory profiles, with half-saturation constant (S0.5) values being distinctly higher for the enzyme extracted from the pathological organ. In contrast to AMP-deaminase isolated from the normal, healthy liver, where presence of relatively large (68 kDa) protein fragment was also detected, only smaller protein fragments were identified, while SDS-PAG electrophoresis of AMP-deaminase isolated from the cirrhotic liver was performed. The obtained results indicate clearly that advanced proteolytic processes occurring in the cirrhotic liver may affect structural integrity of AMP-deaminase studied, making enzyme less active and less sensitive to regulatory action of important allosteric effectors.     

A Paecilomyces fumosoroseus mutant over-producing chitinase displays enhanced virulence against Bemisia tabaci

A Paecilomyces fumosoroseus strain was mutagenized by u.v. Among 200 colonies, one mutant (M84), showed a large and stable chitin hydrolysis-halo. Glucose consumption and biomass production were similar for M84 and the parental strain. Chitinase was inducible by chitin and repressed by glucose in both strains but, when they were grown on minimal medium plus colloidal chitin as sole carbon source, the parental and M84 strains yielded 198 and 690 mol N-acetylglucosamine, respectively. This results indicate that the mutant strain synthesized a chitinase with a higher activity. Bioassays against Bemisia tabaci nymph, showed that M84 incited a 2-fold higher incidence of disease compared to the parental strain.     

A fragment of chloroplast DNA was transferred horizontally,probably from non-eudicots,to mitochondrial genome of <Emphasis Type="Italic">Phaseolus</Emphasis>

The mitochondrial genomes of some Phaseolus species contain a fragment of chloroplast trnA gene intron, named pvs-trnA for its location within the Phaseolus vulgaris sterility sequence (pvs). The purpose of this study was to determine the type of transfer (intracellular or horizontal) that gave rise to pvs-trnA. Using a PCR approach we could not find the respective portion of the trnA gene as a part of pvs outside the Phaseolus genus. However, a BLAST search revealed longer fragments of trnA present in the mitochondrial genomes of some Citrus species, Helianthus annuus and Zea mays. Basing on the identity or near-identity between these mitochondrial sequences and their chloroplast counterparts we concluded that they had relocated from chloroplasts to mitochondria via recent, independent, intracellular DNA transfers. In contrast, pvs-trnA displayed a relatively higher sequence divergence when compared with its chloroplast counterpart from Phaseolus vulgaris. Alignment of pvs-trnA with corresponding trnAfragments from 35 plant species as well as phylogenetic analysis revealed that pvs-trnA grouped with non-eudicot sequences and was well separated from all Fabalessequences. In conclusion, we propose that pvs-trnA arose via horizontal transfer of a trnA intron fragment from chloroplast of a non-eudicot plant to Phaseolus mitochondria. This is the first example of horizontal transfer of a chloroplast sequence to the mitochondrial genome in higher plants.     

Diurnal rhythms of pinealocyte ultrastructure, pineal serotonin content and plasma melatonin level in the domestic pig

The study was conducted to investigate diurnal changes in pinealocyte ultrastructure, pineal serotonin content and plasma melatonin concentration in the domestic pig. The immature pigs (n=24) were kept under a cycle of 12 h light : 12 h dark, with a photophase between 0800 and 2000. During the photophase the animals were exposed to direct sunlight. After four weeks the gilts were slaughtered at 0900, 1400, 2100 and 0200. The pineals were removed and divided into two parts - one for quantitative ultrastructural study (by a point count method) and one for serotonin assay. Simultaneously, blood samples were taken for melatonin assay. The relative volume of mitochondria in pinealocyte perikarya was significantly higher at 1400 than at 0200 and 0900 as well as at 2100 than at 0200. The relative volume of Golgi apparatus was higher at 0900 and 1400 than at 0200. The relative volume of dense bodies of the MBB-1 type in pinealocyte perikarya was significantly lower at 1400 and 2100 than at 0900. In contrast, the relative volume of MBB-2 was higher at 1400 than at 0900 and 0200. The numerical density of DCV in perikarya was significantly higher at 0200 than at 1400. No significant differences were found in rough endoplasmic reticulum, lysosomes and multivesicular bodies. The pineal serotonin content showed a prominent rhythm with the maximum at 1400. The plasma melatonin concentration was significantly higher at 0200 than at 0900, 1400 and 2100. The obtained results demonstrate that both pinealocyte ultrastructure and pineal biochemistry in the pig undergo significant changes in the course of the diurnal rhythm.     

Characterisation of regenerants obtained under selective conditions after Agrobacterium-mediated transformation of citrus explants reveals production of silenced and chimeric plants at unexpected high frequencies

Genetic transformation has been achieved for several citrus genotypes. However, regeneration of escapes at high frequency is a major problem, making the available procedures rather inefficient. Attempts to improve selection by increasing the concentration of kanamycin, used as the selective agent, or substituting it by geneticin have been unsuccessful. Here, we have critically assessed the actual frequency and origin of escapes in citrus by using visual screening with -glucuronidase (gusA) and green fluorescent protein (gfp) markers, by studying the persistence of engineered Agrobacterium in the explants, and by characterising through Southern blot analysis all the regenerants obtained under kanamycin selection. Our results show that inefficient selection could be attributed to the protection of the non-transformed cells from the selective agent by the surrounding transformed cells, and to the persistence of kanamycin-resistance Agrobacterium in explant tissues over long periods of time after co-cultivation. This also explained the high frequency (12%) of chimeric shoots that were commonly recovered. High frequency regeneration of chimeras that resulted from the fusion of different transformation events is reported for the first time. On the other hand, molecular analysis of all the regenerants reveals that transformation frequency is underestimated when based on the expression of a screenable marker gene, and that low expressors and silenced lines could account for at least 25% of those plants considered escapes based on selectable and screenable marker analysis. Consequences of these results at the practical level are also discussed.