374 research outputs found
Phylogeny of the Sepia pharaonis species complex (Cephalopoda: Sepiida) based on analyses of mitochondrial and nuclear DNA sequence data
The pharaoh cuttlefish, Sepia pharaonis Ehrenberg, 1831, is a commercially fished species found from
Japan to East Africa. Previous morphological and genetic work (the latter based on the 16S rRNA
mitochondrial gene) suggested that S. pharaonis is a species complex, but relationships within the
complex remained unresolved. To clarify these relationships, we have sequenced an additional mitochondrial
gene region (cytochrome oxidase subunit I) and a nuclear gene region (rhodopsin) from
over 50 specimens from throughout the range of S. pharaonis. We have also added sequence data from
two specimens of Sepia ramani Neethiselvan, 2001, collected in southeastern India. Sepia ramani is a
species that is morphologically very similar to S. pharaonis, and there is some question regarding its
status as a distinct species. Phylogenetic analyses of a dataset comprising all three-gene regions
revealed a monophyletic S. pharaonis complex consisting of a western Indian Ocean clade, a northeastern
Australia clade, a Persian Gulf/Arabian Sea (‘Iranian’) clade, a western Pacific clade and a
central Indian Ocean clade. Relationships among these clades remain somewhat poorly supported
except for a clade comprising the Iranian clade, the western Pacific clade and the central Indian
Ocean clade. One S. pharaonis specimen was collected in the Arabian Sea, but was found to be a
member of the western Indian Ocean clade, suggesting that gene flow between these regions has
either occurred recently or is ongoing. Both specimens of S. ramani are members of the S. pharaonis
complex, but their mtDNA haplotypes are not closely related – one is a member of the central
Indian Ocean clade, while the other is rather distantly related to the northeastern Australia clade.
We suggest that ‘S. pharaonis’ may consist of several species, but morphological work is needed to
clarify species-level taxonomy within this complex
Human PrimPol is a highly error-prone polymerase regulated by single-stranded DNA binding proteins
PrimPol is a recently identified polymerase involved in eukaryotic DNA damage tolerance, employed in both re-priming and translesion synthesis mechanisms to bypass nuclear and mitochondrial DNA lesions. In this report, we investigate how the enzymatic activities of human PrimPol are regulated. We show that, unlike other TLS polymerases, PrimPol is not stimulated by PCNA and does not interact with it in vivo. We identify that PrimPol interacts with both of the major single-strand binding proteins, RPA and mtSSB in vivo. Using NMR spectroscopy, we characterize the domains responsible for the PrimPol-RPA interaction, revealing that PrimPol binds directly to the N-terminal domain of RPA70. In contrast to the established role of SSBs in stimulating replicative polymerases, we find that SSBs significantly limit the primase and polymerase activities of PrimPol. To identify the requirement for this regulation, we employed two forward mutation assays to characterize PrimPol's replication fidelity. We find that PrimPol is a mutagenic polymerase, with a unique error specificity that is highly biased towards insertion-deletion errors. Given the error-prone disposition of PrimPol, we propose a mechanism whereby SSBs greatly restrict the contribution of this enzyme to DNA replication at stalled forks, thus reducing the mutagenic potential of PrimPol during genome replication
The membrane protein ANKH is crucial for bone mechanical performance by mediating cellular export of citrate and ATP
The membrane protein ANKH was known to prevent pathological mineralization of joints and was thought to export pyrophosphate (PPi) from cells. This did not explain, however, the presence of ANKH in tissues, such as brain, blood vessels and muscle. We now report that in cultured cells ANKH exports ATP, rather than PPi, and, unexpectedly, also citrate as a prominent metabolite. The extracellular ATP is rapidly converted into PPi, explaining the role of ANKH in preventing ankylosis. Mice lacking functional Ank (Ankank/ank mice) had plasma citrate concentrations that were 65% lower than those detected in wild type control animals. Consequently, citrate excretion via the urine was substantially reduced in Ankank/ank mice. Citrate was even undetectable in the urine of a human patient lacking functional ANKH. The hydroxyapatite of Ankank/ank mice contained dramatically reduced levels of both, citrate and PPi and displayed diminished strength. Our results show that ANKH is a critical contributor to extracellular citrate and PPi homeostasis and profoundly affects bone matrix composition and, consequently, bone quality
Girls and Boys Born before 28 Weeks Gestation: Risks of Cognitive, Behavioral, and Neurologic Outcomes at Age 10 Years
To compare the prevalence of cognitive, neurological, and behavioral outcomes at 10 years of age in 428 girls and 446 boys who were born extremely preterm (EP)
The Relationship of Maternal Prepregnancy Body Mass Index and Pregnancy Weight Gain to Neurocognitive Function at Age 10 Years among Children Born Extremely Preterm
OBJECTIVE: To assess the association between maternal prepregnancy body mass index and adequacy of pregnancy weight gain in relation to neurocognitive function in school-aged children born extremely preterm.
STUDY DESIGN: Study participants were 535 ten-year-old children enrolled previously in the prospective multicenter Extremely Low Gestational Age Newborns cohort study who were products of singleton pregnancies. Soon after delivery, mothers provided information about prepregnancy weight. Prepregnancy body mass index and adequacy of weight gain were characterized based on this information. Children underwent a neurocognitive evaluation at 10 years of age.
RESULTS: Maternal prepregnancy obesity was associated with increased odds of a lower score for Differential Ability Scales-II Verbal IQ, for Developmental Neuropsychological Assessment-II measures of processing speed and visual fine motor control, and for Wechsler Individual Achievement Test-III Spelling. Children born to mothers who gained an excessive amount of weight were at increased odds of a low score on the Oral and Written Language Scales Oral Expression assessment. Conversely, children whose mother did not gain an adequate amount of weight were at increased odds of a lower score on the Oral and Written Language Scales Oral Expression and Wechsler Individual Achievement Test-III Word Reading assessments.
CONCLUSION: In this cohort of infants born extremely preterm, maternal obesity was associated with poorer performance on some assessments of neurocognitive function. Our findings are consistent with the observational and experimental literature and suggest that opportunities may exist to mitigate risk through education and behavioral intervention before pregnancy
Extremely low gestational age and very low birthweight for gestational age are risk factors for autism spectrum disorder in a large cohort study of 10-year-old children born at 23-27 weeks’ gestation
No prospective cohort study of high-risk children has used rigorous exposure assessment and optimal diagnostic procedures to examine the perinatal antecedents of autism spectrum disorder (ASD), separately among those with and without cognitive impairment
Not Available
Not AvailableThe pharaoh cuttlefish, Sepia pharaonis Ehrenberg, 1831, is a commercially fished species found from
Japan to East Africa. Previous morphological and genetic work (the latter based on the 16S rRNA
mitochondrial gene) suggested that S. pharaonis is a species complex, but relationships within the
complex remained unresolved. To clarify these relationships, we have sequenced an additional mitochondrial
gene region (cytochrome oxidase subunit I) and a nuclear gene region (rhodopsin) from
over 50 specimens from throughout the range of S. pharaonis. We have also added sequence data from
two specimens of Sepia ramani Neethiselvan, 2001, collected in southeastern India. Sepia ramani is a
species that is morphologically very similar to S. pharaonis, and there is some question regarding its
status as a distinct species. Phylogenetic analyses of a dataset comprising all three-gene regions
revealed a monophyletic S. pharaonis complex consisting of a western Indian Ocean clade, a northeastern
Australia clade, a Persian Gulf/Arabian Sea (‘Iranian’) clade, a western Pacific clade and a
central Indian Ocean clade. Relationships among these clades remain somewhat poorly supported
except for a clade comprising the Iranian clade, the western Pacific clade and the central Indian
Ocean clade. One S. pharaonis specimen was collected in the Arabian Sea, but was found to be a
member of the western Indian Ocean clade, suggesting that gene flow between these regions has
either occurred recently or is ongoing. Both specimens of S. ramani are members of the S. pharaonis
complex, but their mtDNA haplotypes are not closely related – one is a member of the central
Indian Ocean clade, while the other is rather distantly related to the northeastern Australia clade.
We suggest that ‘S. pharaonis’ may consist of several species, but morphological work is needed to
clarify species-level taxonomy within this complex.Not Availabl
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