ABSTRACT
Hydrolytic enzymes from hypopharyngeal gland extracts of newly emerged, nurse and foraging workers of two eusocial bees, Scaptotrigona postica, a native Brazilian stingless bee, and the Africanized honey bee (Apis mellifera) in Brazil, were compared. The hypopharyngeal gland is rich in enzymes in both species. Fifteen different enzymes were found in the extracts, with only a few quantitative differences between the species. Some of the enzymes present in the extracts may have intracellular functions, while others seem to be digestive enzymes. Scaptotrigona postica, had lower beta-glucosidase and higher lipase esterase activities than A. mellifera. The differences may be due to different feeding habits and behavioral peculiarities of the two species.
Subject(s)
Bees/enzymology , Exocrine Glands/enzymology , Hydrolases/isolation & purification , Hypopharynx/enzymology , Animals , Female , Hydrolases/classificationABSTRACT
Hydrolytic enzymes from hypopharyngeal gland extracts of newly emerged, nurse and foraging workers of two eusocial bees, Scaptotrigona postica, a native Brazilian stingless bee, and the Africanized honey bee (Apis mellifera) in Brazil, were compared. The hypopharyngeal gland is rich in enzymes in both species. Fifteen different enzymes were found in the extracts, with only a few quantitative differences between the species. Some of the enzymes present in the extracts may have intracellular functions, while others seem to be digestive enzymes. Scaptotrigona postica, had lower beta-glucosidase and higher lipase esterase activities than A. mellifera. The differences may be due to different feeding habits and behavioral peculiarities of the two species.
Subject(s)
Animals , Female , Bees/enzymology , Exocrine Glands/enzymology , Hydrolases/isolation & purification , Hypopharynx/enzymology , Hydrolases/classificationABSTRACT
Upregulation of cyclo-oxygenase 2 (COX-2) expression is frequently found in a variety of human cancers. In this study, we examined COX-2 expression in squamous cell carcinoma of the hypopharynx. COX-2 messenger RNA (mRNA) analyzed by reverse-transcription polymerase chain reaction was detected in 87% (20 of 23) of tumor tissues. Expression of COX-2 protein was examined by Western blot analysis. COX-2 protein levels were increased in tumor tissues and correlated with the expression level of mRNA. Immunohistochemical study was performed to detect the subcellular localization of COX-2. Our results showed that COX-2 was predominantly detected in cancer cells, and the staining pattern was cytoplasmic. Several histologically normal adjacent tissues obtained from these patients were also investigated. We found that COX-2 mRNA was detectable in these tissues. However, COX-2 mRNA and protein levels were lower in these tissues than in tumor specimens. In contrast, COX-2 mRNA and protein levels in normal oral mucosa obtained from healthy volunteers were very low or undetectable. The frequency of COX-2 overexpression was significantly higher in the N1-N3 group than in the N0 group. These results suggest that overexpression of COX-2 is linked with increased lymphatic invasion in hypopharyngeal carcinoma. Collectively, these results suggest that overexpression of COX-2 is a frequent phenomenon in hypopharyngeal carcinoma and may play a role in tumorigenesis of this cancer.
Subject(s)
Carcinoma, Squamous Cell/enzymology , Hypopharynx/enzymology , Isoenzymes/biosynthesis , Pharyngeal Neoplasms/enzymology , Prostaglandin-Endoperoxide Synthases/biosynthesis , Adult , Aged , Blotting, Western , Carcinoma, Squamous Cell/pathology , Cyclooxygenase 2 , Female , Humans , Hypopharynx/pathology , Isoenzymes/genetics , Male , Membrane Proteins , Middle Aged , Pharyngeal Neoplasms/pathology , Prostaglandin-Endoperoxide Synthases/genetics , RNA/metabolism , RNA, Neoplasm/analysis , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
Major proteins synthesized in the hypopharyngeal gland of the worker honeybee change from bee-milk proteins to alpha-glucosidase in accordance with the age-dependent role change of the worker bee. Previously, we showed that the gene for alpha-glucosidase is expressed specifically in the forager-bee gland [Ohashi, K., Sawata, M., Takeuchi, H., Natori, S. & Kubo, T. (1996) Biochem. Biophys. Res. Commun. 221, 380-385]. Here, we describe the isolation and analysis of cDNAs for two bee-milk 56-kDa and 64-kDa proteins. The 56-kDa protein was a glycoprotein which shared 63.2% and 56.9% amino acid sequence identities with proteins encoded by cDNA for royal-jelly-related protein 57-1 (pRJP57-1) and pRJP57-2. The 64-kDa protein cDNA was identical to pRJP57-1. Thus, these bee-milk proteins seem to form a structurally related protein family. The gene for the 64-kDa protein/RJP57-1 was expressed specifically in the nurse-bee gland, whereas that for the 56-kDa protein was expressed in both the nurse-bee and forager-bee glands. mRNAs for the 56-kDa and 64-kDa proteins were detected by in situ hybridization in a whole acinus of the nurse-bee gland, whereas mRNAs for the 56-kDa protein and alpha-glucosidase were detected in that of the forager-bee gland. Therefore, the individual secretory cells of the acinus of the hypopharyngeal gland were shown to express these genes differently with the age-dependent role change of the worker bee.
Subject(s)
Bees/genetics , Gene Expression Regulation , Glycoproteins/genetics , Insect Proteins/genetics , Aging , Amidohydrolases/metabolism , Amino Acid Sequence , Animals , Base Sequence , Bees/metabolism , Blotting, Northern , Cloning, Molecular , Electrophoresis, Polyacrylamide Gel , Exocrine Glands/metabolism , Fatty Acids/chemistry , Glycoproteins/biosynthesis , Glycoproteins/chemistry , Glycoproteins/isolation & purification , Glycosylation , Hypopharynx/cytology , Hypopharynx/enzymology , Hypopharynx/metabolism , In Situ Hybridization , Insect Proteins/biosynthesis , Insect Proteins/chemistry , Molecular Sequence Data , Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase , RNA/analysis , RNA-Binding Proteins , Sequence Homology, Amino Acid , alpha-Glucosidases/biosynthesis , alpha-Glucosidases/geneticsABSTRACT
Protein tyrosine kinases (PTK) and protein tyrosine phosphatases (PTPase) activity in tumor tissue, obtained from 107 patients with squamous cell carcinoma of the upper aerodigestive tract, was determined. In 79 patients samples were also taken from a histologically proven non-tumourous part of the mucosa. In this extensive study we confirmed our previous findings of increased enzyme activities (cytosol PTK, membranes PTK, cytosol PTPase) in non-tumour tissues compared with control tissues. These biochemical changes suggesting a premalignant mucosa could not be correlated to a higher probability of secondary tumours.
