International journal of biochemistry and molecular biology最新文献

Objectives: Jumonji C domain-containing (JMJD) 2B (JMJD2B) is a transcriptional cofactor and histone demethylase that is involved in prostate cancer formation. However, how its function is regulated by posttranslational modification has remained elusive. Hence, we examined if JMJD2B would be regulated by lysine methylation.

Methods: Through in vitro methylation assays and Western blotting with methyl-lysine specific antibodies, we analyzed lysine methylation within JMJD2B. Identified methylated lysine residues were mutated to arginine residues and the respective impact on JMJD2B transcriptional activity measured with a reporter gene assay in human LNCaP prostate cancer cells.

Results: We discovered that JMJD2B is methylated on up to six different lysine residues. Further, we identified the suppressor of variegation 3-9/enhancer of zeste/trithorax (SET) domain-containing protein 7/9 (SET7/9) as the methyltransferase being responsible for this posttranslational modification. Mutating the methylation sites in JMJD2B to arginine residues led to diminished coactivation of the Ju-nana (JUN) transcription factor, which is a known oncogenic protein in prostate tumors. In contrast, methylation of JMJD2B had no impact on its ability to coactivate another transcription factor associated with prostate cancer, the DNA-binding protein E26 transformation-specific (ETS) variant 1 (ETV1). Consistent with a potential joint action of JMJD2B, SET7/9 and JUN in prostate cancer, the expression of JMJD2B in human prostate tumors was positively correlated with both SET7/9 and JUN levels.

Conclusions: The identified SET7/9-mediated methylation of JMJD2B appears to impact its cooperation with selected interacting transcription factors in prostate cancer cells. Given the implicated roles of JMJD2B beyond prostate tumorigenesis, SET7/9-mediated methylation of JMJD2B possibly also influences the development of other cancers, while its impairment might have relevance for obesity or a global developmental delay that can be elicited by reduced JMJD2B activity.

Background: Phospholipids are highly diverse molecules with pleiotropic biological roles, from membrane components and signaling molecules, whose composition can change in response to both endogenous and external stimuli. Recent lipidomic studies on edible bivalve mollusks were focused on lipid nutritional value and growth requirements. However, no data are available on phospholipid profiles during bivalve larval development. In the model marine bivalve Mytilus galloprovincialis, early larvae (up to 48 hours post fertilization-hpf) undergo dramatic molecular and functional changes, including shell biogenesis and neurogenesis, that are sustained by egg lipid reserves. Changes in phospholipid composition may also occur participating in the complex processes of early development.

Objective: The lipidome of M. galloprovincialis eggs and early larval stages (24 and 48 hpf) was investigated in order to identify possible changes in phospholipid classes and related metabolic pathways that may play a role in key steps of development.

Materials and methods: Lipidomic analysis were performed by NMR spectroscopy and liquid chromatography-mass spectrometry (LC-MS), with focus on phospholipids. Shifts in relative species composition of phosphatidylcholine, phosphatidylethanolamine, plasmalogen, and ceramide aminoethylphosphonate-CAEP, the bivalve analogue of the main mammalian ceramide sphingomyelin, were observed. Expression of genes involved in ceramide homeostasis was also modulated from eggs to early larval stages.

Results: The results represent the first data on changes in phospholipid composition in bivalve larvae and suggest a functional role of phospholipids in mussel early development.

Conclusion: The results underline the importance of lipidomic studies in bivalve larvae, in both physiological conditions and in response to environmental stress.

Background: The diverse nature of carbohydrate structures and linkages requires a variety of enzymes responsible for sugar degradation. The E. coli periplasmic protein encoded by the bglX gene has been assigned to glycoside hydrolase family 3 and is predicted to function as a β-glucosidase.

Objectives: We investigated the catalytic properties of the E. coli protein BglX and identified two functionally important amino acid residues.

Methods: The bglX gene was cloned into a pET20b(+) vector, and three mutants, D111N, D287G, and E293Q, were generated using site-directed mutagenesis. Kinetic studies were performed on the wild-type and mutant enzymes.

Results: Substrate specificity tests indicated that the BglX enzyme hydrolyzes β-glycosidic bonds in nitrophenyl-β-glycosides and demonstrates greater activity towards galactose-containing substrates compared to glucose derivatives. Monomeric glucose and galactose inhibit enzyme activity to a different degree in a substrate-dependent manner. In addition, BglX can hydrolyze lactose but not cellobiose, maltose, or laminarin. Subsequently, E. coli cells overexpressing active BglX have a growth advantage on minimal media supplemented with lactose as a carbon source. Mutation of D287 or D111 residues negatively affected the activity of BglX indicating their involvement in catalysis. Overexpression of BglX by E. coli cells did not increase biofilm formation.

Conclusions: The low activity towards glucose-containing substrates and significantly elevated activity towards galactosides suggests that β-glucosidase activity may not be the primary function of the BglX enzyme.

Background: There is insufficient data on the prevalence and consequences of eating disorders in Type 2 diabetic patients.

Objective: To evaluate the presence of eating disorders (ED) and their association with glycaemic control and metabolic parameters in adult patients with type 2 diabetes mellitus (T2DM).

Materials and methods: A cross-sectional study on 145 patients was conducted in the medicine outpatient unit of HAHC Hospital, Jamia Hamdard tertiary care center. The Eating Attitudes Test (EAT-26) was used to screen for ED in adults with T2DM. The Score of less than 20 and more than 30 on EAT-26 questionnaire was defined as control for participants and relevant medical details like duration of treatment, glycaemic control, complications were recorded.

Results: A total of 145 diabetic individuals participated in this study. Out of these, 17.3% of individuals with T2DM screened positive for ED on EAT-26 scale and had a significant positive correlation in <20 groups and a significant negative correlation in >30 groups.

Conclusion: Our study reveals that eating disorders are not very common in our clinical population of T2DM, the prevalence rates of eating disorders are lower in patients with T2DM than those reported from developed western countries.

Type 1 diabetes mellitus (T1DM), associated with autoimmune destruction of pancreatic β cells, is observed in children and adolescents.

Objective: We investigated the potential association of the apolipoprotein M (APOM) polymorphisms rs707921, rs805264, rs805296, rs805297, and rs9404941 in childhood-onset T1DM (n = 144) and compared them to those in healthy (mostly Euro-Brazilian) children (n = 168).

Methods: This project was approved by the Ethics Committee of the Federal University of Parana (CAAE 24676613.6.0000.0102). Genotyping was performed using PCR-restriction fragment length polymorphisms (rs805296 and rs9404941) and TaqMan probes (rs707921, rs805264, and rs805297).

Results: All polymorphisms were in Hardy-Weinberg equilibrium. In the codominant model, no significant differences (P > 0.05) were observed in genotype and allele frequencies between healthy controls and children with T1DM. The minor allele frequencies (95% CI) for healthy subjects were rs707921 (A, 10.7%; 7-14%), rs805264 (A, 6.5%; 4-9%), rs805296 (C, 3.6%; 2-6%), rs805297 (A, 22.6%; 22-31%), and rs9404941 (C, 2.7%; 1-4%). The frequencies of the rs805297 A allele and rs805296 C allele were similar to those of other Caucasian populations; both the rs707921 and rs805264 A alleles were similar to American and Latin American populations, whereas that of the rs9404941 C allele was lower than that observed in the Caucasian and Asian populations.

Conclusions: Haplotype analysis suggests that rs805297-C, rs9404941-T, rs805296-T, rs805264-G, and rs707921-C conferred risk (OR: 4.25; 95% CI: 1.81-10.1) to childhood-onset T1DM in the Euro-Brazilian population.

The search for alternative control of excessive milk secretion associated with exclusive breast feeding necessitated this study. This study was designed to investigate the effect of methanolic crude extract of Aframomum melegueta (A.m) seed by measuring serum concentrations of selected lactogenic (prolactin, estradiol and progesterone) hormones in lactating and non-lactating Albino rats. A total of 18 non-lactating and lactating rats each were assigned into three (3) treatments of 6 rats each. Treatment 1 and 2 (controls) received 0.11 mg/kg/day of reference drug (bromocriptine) and 100 mg/kg/day of Dimethylsulfoxide (Dmso) 1 ml:9 ml of normal saline which is referred to as normal control in this study. Treatment 3 received 100 mg/kg/day of A.m methanolic crude extract. Serum samples were collected and analyzed for prolactin, estradiol and progesterone by ELISA techniques. The result obtained showed a 21.13% and 25.12% significant (P<0.05) reduction in serum concentration of prolactin for both non-lactating (26.15±0.15 ng/ml) and lactating (14.90±1.16 ng/ml) rats relative to (33.23±1.82 and 19.90±1.16 ng/ml) normal control rats but a significant (P<0.05) increase (26.15±0.15 ng/ml; 14.90±1.16 ng/ml) in serum levels of the same hormone relative to (12.56±0.89 ng/ml; 10.56±0.29 ng/ml) reference control drug (bromocriptine) in both groups. Serum estradiol levels were significantly (P<0.05) reduced by methanol extract relative to normal control rats in both groups. There was however, no significant (P>0.05) changes in serum levels of estradiol relative to reference control drugs in both rats. Serum levels of progesterone were not significantly altered in both groups relative to normal control rats. The above findings confer on the extract antilactogenic capability and hence a good alternative to bromocriptine.