Association of immunoglobulin GM allotypes with longevity in long-living individuals from Southern Italy

Background

The aim of this study was to analyse the role of GM allotypes, i.e. the hereditary antigenic determinants expressed on immunoglobulin polypeptide chains, in the attainment of longevity. The role played by immunoglobulin allotypes in the control of immune responses is well known as well as the role of an efficient immune response in longevity achievement. So, it is conceivable that particular GM allotypes may contribute to the generation of an efficient immune response that supports successful ageing, hence longevity.

Methods

In order to show if GM allotypes play a role in the achievement of longevity, we typed the DNA of 95 Long-living individuals (LLIs) and 96 young control individuals (YCs) from South Italy for GM3/17 and GM23+/? alleles.

Results

To demonstrate the role of GM allotypes in the attainment of longevity we compared genotype and allele frequencies of GM allotypes between LLIs and YCs. A global chi-square test (3?×?2) shows that the distribution of genotypes at the GM 3/17 locus is highly significantly different in LLIs from that observed in YCs (p?<?0.0001). The 2?×?2 chi-square test shows that the carriers of the GM3 allele contribute to this highly significant difference. Accordingly, GM3 allele is significantly overrepresented in LLIs. No significant differences were instead observed regarding GM23 allele.

Conclusion

These preliminary results show that GM3 allotype is significantly overrepresented in LLIs. To best of our knowledge, this is the first study performed to assess the role of GM allotypes in longevity. So, it should be necessary to verify the data in a larger sample of individuals to confirm GM role in the attainment of longevity.

     

MATCH-UP/MATRIX: a microcomputer program designed to search for protein primary structure homology

MATCH-UP/MATRIX is a program designed to aid the investigatorinterested in determining primary protein structure. It is writtenin Applesoft BASIC for the Apple lle microcomputer. MATCH-UPwill survey any set of proteinaceous materials for amino acidsequence homology; however, it is primarily intended to comparethe structures of newly sequenced peptides with the establishedstructure of a protein with suspected homology. Any peptide-to-proteinalignment which shows a homology greater than or equal to thepercentage specified by the user will result in output. MATRIXwill compare the sequences of two proteins (peptides) in whateveralignment specified by the user and is intended to spot insertionsand/or deletions between structures. Received on December 2, 1985; accepted on March 10, 1986     

Kinetic and anion inhibition studies of a β-carbonic anhydrase (FbiCA 1) from the C4 plant Flaveria bidentis

Several β-carbonic anhydrases (CAs, EC 4.2.1.1) are present in all land plants examined thus far. Here we report the first detailed biochemical characterization of one such isoform, FbiCA 1, from the C₄ plant Flaveria bidentis, which was cloned, purified and characterized as recombinant protein. FbiCA 1 has an interesting CO₂ hydrase catalytic activity (k_cat of 1.2 × 10⁵ and k_cat/K_m of 7.5 × 10⁶ M^?1 × s^?1) and was moderately inhibited by most simple/complex inorganic anions. Potent FbiCA 1 inhibitors were also detected, such as trithiocarbonate, diethyldithiocarbamate, sulfamide, sulfamic acid, phenylboronic acid and phenylarsonic acid (K_Is in the range of 4–60 μM). Such inhibitors may be used as tools to better understand the role of various β-CA isoforms in photosynthesis.     

Expression of the mRNA encoding truncated PPARα does not correlate with hepatic insensitivity to peroxisome proliferators

Two alternatively spliced forms of human PPAR mRNA, PPAR1 and PPAR2, have been identified. PPAR1 mRNA gives rise to an active PPAR protein while PPAR2 mRNA gives rise to a form of PPAR which lacks the ligand-binding domain. PPAR2 is unable to activate a peroxisome proliferator response element (PPRE) reporter gene construct in transient transfection assays. Both PPAR1 and PPAR2 mRNA are present in human liver, kidney, testes, heart, small intestine, and smooth muscle. In human liver, PPAR2 mRNA abundance is approximately half that of PPAR1 mRNA; a correlation analysis of PPAR1 and PPAR2 mRNA mass revealed an r-value of 0.75 (n = 18). Additional studies with intact liver from various species, showed that the PPAR2/PPAR1 mRNA ratios in rat, rabbit, and mouse liver were less than 0.10; significantly lower than the 0.3 and 0.5 ratios observed in monkey and human livers, respectively. To determine if a high PPAR2/PPAR1 mRNA ratio was associated with insensitivity to peroxisome proliferators, we treated human, rat, and rabbit hepatocytes with WY14643, a potent PPARa activator, and measured acyl CoA oxidase (ACO) mRNA levels. Rat ACO mRNA levels increased markedly in response to WY14643 while human and rabbit hepatocytes were unresponsive. Thus, although the PPAR2/PPAR1 mRNA ratio is low in rabbits, this species is not responsive to peroxisome proliferators. Further studies with male and female rats, which vary significantly in their response to peroxisome proliferators, showed little difference in the ratio of PPAR2/PPAR1 mRNA. These data suggest that selective PPAR2 mRNA expression is not the basis for differential species or gender responses to peroxisome proliferators.     

Annexin2 coating the surface of enlargeosomes is needed for their regulated exocytosis

Enlargeosomes are small cytoplasmic vesicles that undergo rapid, Ca2+-dependent exo/endocytosis. The role of the cytoskeleton in these processes was unknown. In PC12-27 cells, microtubule disassembly had little effect on enlargeosomes, whereas microfilament disassembly increased markedly both their resting and stimulated exocytosis, and inhibited their endocytosis. Even at rest enlargeosomes are coated at their cytosolic surface by an actin-associated protein, annexin2, bound by a dual, Ca2+-dependent and Ca2+-independent mechanism. In contrast, the other enlargeosome marker, desmoyokin/Ahnak, is transported across the organelle membrane, apparently by an ABC transporter, and binds to its lumenal face. Annexin2-GFP expression revealed that, upon stimulation, the slow and random enlargeosome movement increases markedly and becomes oriented toward the plasma membrane. After annexin2 downregulation enlargeosome exocytosis induced by both [Ca2+]i rise and cytoskeleton disruption is inhibited, and the NGF-induced differentiation is blocked. Binding of annexin2 to the enlargeosome membrane, the most extensive ever reported (>50% annexin2 bound to approximately 3% of total membrane area), seems therefore to participate in the regulation of their exocytosis.     

Stimulated T cell and natural killer (NK) cell lines fail to synthesize leukotriene B4

The ability of leukotriene B4 (LTB4) to influence T cell and natural killer (NK) cell functions makes the question of LTB4 generation by these cells important to address. Consequently, LTB4 generation was evaluated in a human (Jurkat), and in a murine (EL-4) T cell line as well as in a rat NK cell line (RNK-16). Incubation of each of the 3 cell lines with [1-14C]arachidonic acid alone or in the presence of phytohemagglutinin (PHA), of calcium ionophore A23187, or of concanavalin A (Con A) plus the phorbol ester 12-0-tetradecanoylphorbol-13-acetate (TPA) failed to generate radiolabelled LTB4 or other eicosanoids as determined by thin layer radiochromatography. Using two different radioimmunoassays for LTB4 also failed to demonstrate the generation of LTB4 under basal or stimulated conditions. These results support earlier studies that demonstrate that T cells are not capable of de novo synthesis of prostaglandins, thromboxanes, or leukotrienes and also provide evidence that NK cells also do not have the capacity to generate LTB4 or other eicosanoids. Our findings are also critically discussed in relation to studies claiming eicosanoid synthesis by T cells.