No abstract

A new human leukocyte elastase inhibitor was extracted and purified from a Korean native leech Hirudo nipponia. The inhibitor, called guamerin, has a molecular weight of 6,110 and shows inhibition constant (Ki) of 8.1 x 10(-14) M. It is stable at a wide range of pH from 1 to 11 and heat-stable up to 90 degrees C. The complete amino acid sequence of guamerin reveals a cysteine-rich polypeptide of 57 amino acid residues that shows no similarity to any known elastase inhibitors but has 51% sequence homology with hirustasin. Guamerin has identical spacing of 10 cysteine residues as antistasin-type serine proteinase inhibitors, but the P1 reactive site residue is Met36 instead of Arg. The neighboring sequence of the reactive site consists primarily of hydrophobic amino acid residues. Based on examinations of the target proteinases and the reactive site specificity, guamerin is a new low molecular weight protein that inhibits elastases.

BackgroundThe red turpentine beetle (RTB), Dendroctonus valens LeConte (Coleoptera: Curculionidae, Scolytinae), is a destructive invasive pest of conifers which has become the second most important forest pest nationwide in China. Dendroctonus valens is known to use host odors and aggregation pheromones, as well as non-host volatiles, in host location and mass-attack modulation, and thus antennal olfaction is of the utmost importance for the beetles’ survival and fitness. However, information on the genes underlying olfaction has been lacking in D. valens. Here, we report the antennal transcriptome of D. valens from next-generation sequencing, with the goal of identifying the olfaction gene repertoire that is involved in D. valens odor-processing.ResultsWe obtained 51 million reads that were assembled into 61,889 genes, including 39,831 contigs and 22,058 unigenes. In total, we identified 68 novel putative odorant reception genes, including 21 transcripts encoding for putative odorant binding proteins (OBP), six chemosensory proteins (CSP), four sensory neuron membrane proteins (SNMP), 22 odorant receptors (OR), four gustatory receptors (GR), three ionotropic receptors (IR), and eight ionotropic glutamate receptors. We also identified 155 odorant/xenobiotic degradation enzymes from the antennal transcriptome, putatively identified to be involved in olfaction processes including cytochrome P450s, glutathione-S-transferases, and aldehyde dehydrogenase. Predicted protein sequences were compared with counterparts in Tribolium castaneum, Megacyllene caryae, Ips typographus, Dendroctonus ponderosae, and Agrilus planipennis.ConclusionThe antennal transcriptome described here represents the first study of the repertoire of odor processing genes in D. valens. The genes reported here provide a significant addition to the pool of identified olfactory genes in Coleoptera, which might represent novel targets for insect management. The results from our study also will assist with evolutionary analyses of coleopteran olfaction.

The biochemical role of poly(ADP-ribosyl)ation on internucleosomal DNA fragmentation associated with apoptosis was investigated in HL 60 human premyelocytic leukemia cells. It was found that UV light and chemotherapeutic drugs including adriamycin, mitomycin C, and cisplatin increased poly(ADP-ribosyl)ation of nuclear proteins, particularly histone H1. A poly(ADP-ribose) polymerase inhibitor, 3-aminobenzamide, prevented both internucleosomal DNA fragmentation and histone H1 poly(ADP-ribosyl)ation in cells treated with the apoptosis inducers. When nuclear chromatin was made accessible to the exogenous nuclease in a permeabilized cell system, chromatin of UV-treated cells was more susceptible to micrococcal nuclease than the chromatin of control cells. Suppression of histone H1 poly-(ADP-ribosyl)ation by 3-aminobenzamide reduced the micrococcal nuclease digestibility of internucleosomal chromatin in UV-treated cells. These results suggest that the poly(ADP-ribosyl)ation of histone H1 correlates with the internucleosomal DNA fragmentation during apoptosis mediated by DNA damaging agents. This suggestion is supported by the finding that xeroderma pigmentosum cells which are defective in introducing incision at the site of DNA damage, failed to induce DNA fragmentation as well as histone H1 poly(ADP-ribosyl)ation after UV irradiation. We propose that poly(ADPribosyl)ation of histone H1 protein in the early stage of apoptosis facilitates internucleosomal DNA fragmentation by increasing the susceptibility of chromatin to cellular endonuclease.Apoptosis is an active form of cellular suicide, a process that typically involves morphological changes such as the condensation of chromatin into clumps, nuclear fragmentation, and packaging of nuclear fragments into membrane-enclosed apoptotic bodies. These morphological changes are usually accompanied by biochemical changes including elevation of cytoplasmic Ca 2ϩ and internucleosomal DNA fragmentation (1). Many of the chemotherapeutic drugs and radiation which cause DNA damage are known to induce apoptosis (2-5). It is well established that a variety of DNA damaging agents lower the cellular NAD ϩ content by raising the specific activity of poly(ADPribose) polymerase (PARP) 1 (EC 2.4.2.30) that results from the conformational changes which occur when the zinc finger domains of the enzyme bind to the DNA strand breaks (6, 7). PARP is a nuclear enzyme which transfers the ADP-ribose moiety of NAD ϩ to nuclear proteins including PARP itself and histones in cells (8). In vitro studies have also revealed that topoisomerase I (9), RNA polymerase II (10), DNA polymerase ␣ (11), DNA polymerase ␤ (12), and terminal deoxynucleotidyl transferase (13) are the substrates of PARP. Thus, poly(ADPribosyl)ation has been implicated in many biological responses including DNA replication (14), DNA excision repair (15), cell differentiation (16), and tumor promotion (17).In recent years, the role of poly(ADP-ribosyl)ation in the cell death process has been discussed. The decrease in cellular PARP ...

No abstract