Evolution of mitochondrial uncoupling proteins: novel invertebrate UCP homologues suggest early evolutionary divergence of the UCP family

Current hypothesis about the evolution of uncoupling proteins (UCPs) proposed by suggests that UCP4 is the earliest form of UCP ancestral to all other UCP orthologues. However, this hypothesis is difficult to reconcile with a narrow tissue distribution of UCP4 (which is a brain-specific isoform), suggesting highly specialized rather than anfcestral function for this protein. We searched for UCP2, UCP3, and UCP5 homologues in invertebrate genomes using amplification with degenerate primers designed against UCP2-specific conserved sequences and/or BLASTP search with stringent ad hoc criteria to distinguish between homologues and orthologues of different UCPs. Our study identified invertebrate UCP homologues similar to UCP2 and 3 (which we termed UCP6) and an invertebrate homologue of UCP5. Phylogenetic analysis indicates that there are at least three clades of UCPs in invertebrates, which are closely related to vertebrate UCP1-3, UCP4, and UCP5, respectively, and shows early evolutionary divergence of UCPs, which pre-dates the divergence of protostomes and deuterostomes. It also suggests that the newly identified UCP6 proteins from invertebrates are ancestral to the vertebrate UCP1, UCP2, and UCP3, and that divergence of these three vertebrate orthologues occurred late in evolution of the vertebrates. This study refutes the hypothesis of Hanak and Jezek (2001) that UCP4 is an ancestral form for all UCPs, and shows early evolutionary diversification of this protein family, which corresponds to their proposed functional diversity in regulation of proton leak, antioxidant defense and apoptosis.

CYP19 gene polymorphism in endometrial cancer patients

PURPOSE

Initiation/promotion of endometrial cancer is known to be associated with estrogenic influence. Therefore, it is possible that some allelic polymorphisms of the genes involved in steroidogenesis or steroid metabolism contribute to endometrial cancer susceptibility.

METHODS

Here, we compared CYP19 (aromatase) gene polymorphism in 85 endometrial cancer patients and in 110 non-affected women.

RESULTS

The genotypes containing the longest alleles (A6 and A7) of CYP19 were found to be over-represented in patients as compared to controls. In addition, these genotypes demonstrated a tendency to be associated with increased concentrations of estradiol and testosterone in postmenopausal patients.

CONCLUSIONS

Thus, CYP19 polymorphism might be one of the genetic risk factors for endometrial cancer development.

Effects of cadmium exposure and intermittent anoxia on nitric oxide metabolism in eastern oysters, Crassostrea virginica

Nitric oxide (NO) is an intracellular signaling molecule synthesized by a group of enzymes called nitric oxide synthases (NOS) and involved in regulation of many cellular functions including mitochondrial metabolism and bioenergetics. In invertebrates, the involvement of NO in bioenergetics and metabolic responses to environmental stress is poorly understood. We determined sensitivity of mitochondrial and cellular respiration to NO and the effects of cadmium (Cd) and intermittent anoxia on NO metabolism in eastern oysters, Crassostrea virginica. NOS activity was strongly suppressed by exposure to 50 μg l–1 Cd for 30 days (4.76 vs 1.19 pmol NO min–1 mg–1 protein in control and Cd-exposed oysters, respectively) and further decreased during anoxic exposure in Cd-exposed oysters but not in their control counterparts. Nitrate/nitrite content (indicative of NO levels) decreased during anoxic exposure to less than 10% of the normoxic values and recovered within 1 h of re-oxygenation in control oysters. In Cd-exposed oysters, the recovery of the normoxic NO levels lagged behind, reflecting their lower NOS activity. Oyster mitochondrial respiration was inhibited by exogenous NO, with sensitivity on a par with that of mammalian mitochondria, and ADP-stimulated mitochondrial respiration was significantly more sensitive to NO than resting respiration. In isolated gill cells, manipulations of endogenous NOS activity either with a specific NOS inhibitor (aminoguanidine) or a NOS substrate (l-arginine) had no effect on respiration, likely due to the fact that mitochondria in the resting state are relatively NO insensitive. Likewise, Cd-induced stimulation of cellular respiration did not correlate with decreased NOS activity in isolated gill cells. High sensitivity of phosphorylating (ADP-stimulated) oyster mitochondria to NO suggests that regulation of bioenergetics is an evolutionarily conserved function of NO and that NO-dependent regulation of metabolism may be most prominent under the conditions of high metabolic flux when the ADP-to-ATP ratio is high.

Distinct prevalence of the CYP19 Delta3(TTTA)(7) allele in premenopausal versus postmenopausal breast cancer patients, but not in control individuals

The CYP19 gene encodes the enzyme aromatase, which plays a key role in the conversion of androgens to oestrogens. A polymorphism in CYP19 in intron 4 (TTTA)n has been reported to be associated with breast cancer (BC) risk, although conflicting evidence has also been published. Here, we employ a non-traditional, highly demonstrative design of a molecular epidemiological study, where the comparison of BC cases and healthy middle-aged female donors was supplemented by an analysis of groups with extreme characteristics of either BC risk (bilateral breast cancer (biBC) patients) or cancer tolerance (tumour-free elderly women aged >or=75 years). None of the (TTTA)n polymorphic variants was significantly overrepresented among the affected women compared with any of the control groups. However, a 3-bp deletion/insertion CYP19 polymorphism, which is located in the same intron approximately 50 bp upstream to the (TTTA)n repeat, was evidently associated with the menopausal status in both the BC and biBC cohorts. In particular, the Delta3(TTTA)(7) allele occurred significantly more frequently in premenopausal than in postmenopausal BC patients (65/172 (38%) versus 67/310 (22%); P=0.0001; Odds Ratio (OR)=2.20 (95% Confidence Interval (CI) 1.46-3.32)), while the perimenopausal cases demonstrated an intermediate value (9/34 (26%)). In the biBC cohort, women who developed both tumours during their premenopausal period had a significantly higher prevalence of the Delta3(TTTA)(7) allele than patients with a postmenopausal onset of bilateral disease (16/46 (35%) versus 8/50 (16%); P=0.035; OR=2.80 (1.08-7.23)); those biBC patients, whose tumours were diagnosed before and after the cessation of menses, displayed an intermediate occurrence of the Delta3(TTTA)(7) allele (7/32 (22%)). Similar tendencies in the Delta3(TTTA)(7) allele distribution in BC and biBC patients suggest that its association with the menopausal status of the patients is truly non-random and thus this observation deserves further detailed investigation.

Tablet-based electroencephalography diagnostics for patients with epilepsy in the West African Republic of Guinea

BACKGROUND AND PURPOSE

Epilepsy is most common in lower-income settings where access to electroencephalography (EEG) is generally poor. A low-cost tablet-based EEG device may be valuable, but the quality and reproducibility of the EEG output are not established.

METHODS

Tablet-based EEG was deployed in a heterogeneous epilepsy cohort in the Republic of Guinea (2018-2019), consisting of a tablet wirelessly connected to a 14-electrode cap. Participants underwent EEG twice (EEG1 and EEG2), separated by a variable time interval. Recordings were scored remotely by experts in clinical neurophysiology as to data quality and clinical utility.

RESULTS

There were 149 participants (41% female; median age 17.9 years; 66.6% ≤21 years of age; mean seizures per month 5.7 ± SD 15.5). The mean duration of EEG1 was 53 ± 12.3 min and that of EEG2 was 29.6 ± 12.8 min. The mean quality scores of EEG1 and EEG2 were 6.4 [range, 1 (low) to 10 (high); both medians 7.0]. A total of 44 (29.5%) participants had epileptiform discharges (EDs) at EEG1 and 25 (16.8%) had EDs at EEG2. EDs were focal/multifocal (rather than generalized) in 70.1% of EEG1 and 72.5% of EEG2 interpretations. A total of 39 (26.2%) were recommended for neuroimaging after EEG1 and 22 (14.8%) after EEG2. Of participants without EDs at EEG1 (n = 53, 55.8%), seven (13.2%) had EDs at EEG2. Of participants with detectable EDs on EEG1 (n = 23, 24.2%), 12 (52.1%) did not have EDs at EEG2.

CONCLUSIONS

Tablet-based EEG had a reproducible quality level on repeat testing and was useful for the detection of EDs. The incremental yield of a second EEG in this setting was ~13%. The need for neuroimaging access was evident.

A model for the monocular line orientation analyzer

A model for monocular line perception by human Ss is based on three basic assumptions: (a) the line's inclination is coded by the maximally excited orientation detector's number; (b) the inclination of the perceived line is equivocally determined by the excitation vector in the subjective space; (c) the analyzer has a maximum differential sensitivity over the whole range of the line inclinations. This simple model for the line inclination analyzer, taking into account the optimization of its sensitivity, provides incomplex explanations for a wide range of psychophysical and neurophysiological data obtained from human and animal experiments.

[A polymorphism study of the CYP19 gene in endometrial cancer patients]

A strong connection is known to exist between initiation/promotion of endometrial cancer and excess of estrogens. Therefore, participation of certain alleles of genetic polymorphisms in steroid biosynthesis or metabolism may be responsible for predisposition to the disease. The present study, comparing CYP19 (aromatase) gene polymorphism in 85 patients and 110 healthy females, pointed to a more frequent occurrence of relatively longer alleles (A6 and A7) of the CYP19 gene in the former group. Furthermore, precisely those genotypes co-occurred more frequently with elevated blood levels of estradiol and testosterone in postmenopausal patients. Hence, CYP19 gene polymorphism may be regarded as a factor of genetic risk for endometrial carcinoma.