Maternal and Cord β-Carotene levels and Their Association with Newborn Hearing Screen Results

Background. β-carotene is one of the few carotenoids that can be endogenously converted to vitamin A, a nutrient essential for inner ear development. While previous studies have identified a protective effect of carotenoids on hearing in adults, the impact of β-carotene on hearing outcomes in neonates is not well understood. The purpose of this study is to investigate the relationship between maternal β-carotene intake, maternal plasma, and umbilical cord plasma β-carotene levels and abnormal Newborn Hearing Screen (NHS) results. Significance of Problem. The prenatal period is critical for auditory development; thus, effectors of auditory development may significantly impact long-term hearing ability. Because maternal nutrition is modifiable, an improved understanding of the relationship between β-carotene levels and hearing outcomes may be relevant for prenatal care recommendations. Hypothesis. We hypothesize that higher levels of β-carotene will be associated with decreased risk of abnormal NHS results. Experimental Design. An IRB-approved study enrolled mother-infant pairs (n=541) at the time of delivery. β-carotene plasma levels were analyzed with HPLC. Maternal intake of β-carotene over the past year was quantified using the validated Harvard Food Frequency Questionnaire. NHS results were obtained from the Electronic Medical Record. Statistical analysis was done using the Mann-Whitney U and logistic regression tests, with p\u3c0.05 considered statistically significant. Results. Of the 541 participants, 8.5% of infants had abnormal NHS results. Higher median maternal β-carotene intake was observed in infants who failed their NHS compared to those who passed (5924 vs. 4722 mcg/day, p=0.019). Higher median maternal plasma levels of both trans- (206 vs. 149 mcg/L, p=0.021) and cis-β-carotene (15.9 vs. 11.2 mcg/L, p=0.015) were observed in infants who failed their NHS. Higher median cord plasma trans β-carotene was observed in infants who failed their NHS (15.5 vs. 8.0 mcg/L, p=0.04). Associations between failed NHS and log-transformed β-carotene intake and serum levels remained in a logistic regression model after adjustment for NICU admission, race/ethnicity, smoking status, maternal age, corrected gestational age, infant sex, and log transformed maternal caloric intake. Conclusion. The observed relationship between higher β-carotene levels and abnormal NHS was unexpected. While other studies suggest both deficient and excessive levels of vitamin A can impact inner ear development, β-carotene levels in our study were not exceptionally high. One possible explanation is that higher maternal β-carotene levels may be indicative of impaired transfer of β-carotene to the fetus. Further study is warranted to better understand the relationship between β-carotene and NHS results.https://digitalcommons.unmc.edu/chri_forum/1063/thumbnail.jp

Impact of COVID-19 Infection During Pregnancy on Neonatal Birth Outcomes

Approximately 116 million births have been reported worldwide in the nine months following the start of the COVID-19 pandemic. Currently, the effects of COVID-19 infection during pregnancy on birth outcomes are not fully understood. An IRB-approved study enrolled 115 mothers since March 2020, 5 of whom had a confirmed history of COVID-19 infection during pregnancy. For each COVID-19-infected mother, two mothers of similar age, gestation period, and race who were not infected with COVID-19 during pregnancy were matched 2-to-1 for a case-control analysis. Descriptive statistics were generated, and the Mann-Whitney U test was used to compare continuous variables between the two groups. Fisher’s Exact test was used to evaluate categorical outcomes between the groups. Phttps://digitalcommons.unmc.edu/surp2021/1007/thumbnail.jp

Manipulator

A manipulator consists of a base unit, a first and a second feeder unit. In order to reduce the height of the manipulator between its standing plane and the plane in which lies a part to be adjusted, the first feeder unit has a recess within which the second feeder unit is located

A positive, growth-based PAM screen identifies noncanonical motifs recognized by the S. pyogenes Cas9.

CRISPR technologies have overwhelmingly relied on the Streptococcus pyogenes Cas9 (SpyCas9), with its consensus NGG and less preferred NAG and NGA protospacer-adjacent motifs (PAMs). Here, we report that SpyCas9 also recognizes sequences within an N(A/C/T)GG motif. These sequences were identified on the basis of preferential enrichment in a growth-based screen in Escherichia coli. DNA binding, cleavage, and editing assays in bacteria and human cells validated recognition, with activities paralleling those for NAG(A/C/T) PAMs and dependent on the first two PAM positions. Molecular-dynamics simulations and plasmid-clearance assays with mismatch-intolerant variants supported induced-fit recognition of an extended PAM by SpyCas9 rather than recognition of NGG with a bulged R-loop. Last, the editing location for SpyCas9-derived base editors could be shifted by one nucleotide by selecting between (C/T)GG and adjacent N(C/T)GG PAMs. SpyCas9 and its enhanced variants thus recognize a larger repertoire of PAMs, with implications for precise editing, off-target predictions, and CRISPR-based immunity

Modular one-pot assembly of CRISPR arrays enables library generation and reveals factors influencing crRNA biogenesis.

CRISPR-Cas systems inherently multiplex through CRISPR arrays—whether to defend against different invaders or mediate multi-target editing, regulation, imaging, or sensing. However, arrays remain difficult to generate due to their reoccurring repeat sequences. Here, we report a modular, one-pot scheme called CRATES to construct CRISPR arrays and array libraries. CRATES allows assembly of repeat-spacer subunits using defined assembly junctions within the trimmed portion of spacers. Using CRATES, we construct arrays for the single-effector nucleases Cas9, Cas12a, and Cas13a that mediated multiplexed DNA/RNA cleavage and gene regulation in cell-free systems, bacteria, and yeast. CRATES further allows the one-pot construction of array libraries and composite arrays utilized by multiple Cas nucleases. Finally, array characterization reveals processing of extraneous CRISPR RNAs from Cas12a terminal repeats and sequence- and context-dependent loss of RNA-directed nuclease activity via global RNA structure formation. CRATES thus can facilitate diverse multiplexing applications and help identify factors impacting crRNA biogenesis