Purification, partial characterization and role in lipid transport to developing oocytes of a novel lipophorin from the cowpea weevil, Callosobruchus maculatus

Lipid transport in arthropods is achieved by highly specialized lipoproteins, which resemble those described in vertebrate blood. Here we describe purification and characterization of the lipid-apolipoprotein complex, lipophorin (Lp), from adults and larvae of the cowpea weevil Callosobruchus maculatus. We also describe the Lp-mediated lipid transfer to developing oocytes. Lps were isolated from homogenates of C. maculatus larvae and adults by potassio bromide gradient and characterized with respect to physicochemical properties and lipid content. The weevil Lp (465 kDa) and larval Lp (585 kDa), with hydrated densities of 1.22 and 1.14 g/mL, contained 34 and 56 percent lipids and 9 and 7 percent carbohydrates, respectively. In both Lps, mannose was the predominant monosaccharide detected by paper chromatography. SDS-PAGE revealed two apolipoproteins in each Lp with molecular masses of 225 kDa (apolipoprotein-I) and 79 kDa (apolipoprotein-II). The lipids were extracted and analyzed by thin-layer chromatography. The major phospholipids found were phosphatidylserine, phosphatidylcholine and phosphatidylethanolamine in adult Lp, and phosphatidylcholine, phosphatidylethanolamine and sphingomyelin in larval Lp. Hydrocarbons, fatty acids and triacylglycerol were the major neutral lipids found in both Lps. Lps labeled in the protein moiety with radioactive iodine (125I-iodine) or in the lipid moiety with fluorescent lipids revealed direct evidence of endocytic uptake of Lps in live oocytes of C. maculatus.

Purification, partial characterization and role in lipid transport to developing oocytes of a novel lipophorin from the cowpea weevil, Callosobruchus maculatus.

Lipid transport in arthropods is achieved by highly specialized lipoproteins, which resemble those described in vertebrate blood. Here we describe purification and characterization of the lipid-apolipoprotein complex, lipophorin (Lp), from adults and larvae of the cowpea weevil Callosobruchus maculatus. We also describe the Lp-mediated lipid transfer to developing oocytes. Lps were isolated from homogenates of C. maculatus larvae and adults by potassio bromide gradient and characterized with respect to physicochemical properties and lipid content. The weevil Lp (465 kDa) and larval Lp (585 kDa), with hydrated densities of 1.22 and 1.14 g/mL, contained 34 and 56% lipids and 9 and 7% carbohydrates, respectively. In both Lps, mannose was the predominant monosaccharide detected by paper chromatography. SDS-PAGE revealed two apolipoproteins in each Lp with molecular masses of 225 kDa (apolipoprotein-I) and 79 kDa (apolipoprotein-II). The lipids were extracted and analyzed by thin-layer chromatography. The major phospholipids found were phosphatidylserine, phosphatidylcholine and phosphatidylethanolamine in adult Lp, and phosphatidylcholine, phosphatidylethanolamine and sphingomyelin in larval Lp. Hydrocarbons, fatty acids and triacylglycerol were the major neutral lipids found in both Lps. Lps labeled in the protein moiety with radioactive iodine (125I-iodine) or in the lipid moiety with fluorescent lipids revealed direct evidence of endocytic uptake of Lps in live oocytes of C. maculatus.

Progesterone receptor (PROGINS) polymorphism and the risk of endometrial cancer development.

The progesterone receptor gene (PROGINS) has been identified as a risk modifier for benign and malignant gynecological diseases. The present case-control study is to evaluate the role of the PROGINS polymorphisms, as risk factor, for endometrial cancer development and to investigate the association between these genetics variants and clinical/pathologic variables of endometrial cancer. PROGINS polymorphism was examined in a total of 121 patients with endometrial cancer and 282 population-based control subjects, all located at the same area in São Paulo, SP, Brazil. The genotyping of PROGINS polymorphism was determined by polymerase chain reaction. The frequencies of PROGINS polymorphism T1/T1, T1/T2, and T2/T2 were 82.6%, 14.9%, and 2.5% in the endometrial cancer patients and 78.4%, 21.6%, and 0% in the controls, respectively. The chi(2) test showed a higher incidence of the T2/T2 genotype in the endometrial cancer group subjects, these results were statistically different (P= 0.012). However, due to the fact that there were no women in the control group showing homozygosis for the allele T2, the correct evaluation of odds ratio could not be properly calculated. Regarding the clinical and pathologic findings observed within the group of patients with endometrial cancer, there was significant correlation between T1/T2 genotype and the presence of myoma (P= 0.048). No correlations were observed among the other variables. These data suggest that the PROGINS polymorphism T2/T2 genotype might be associated with an increased risk of endometrial cancer.