Visual acuity of essential fatty acid-deficient rats

1. Rats were maintained on a diet deficient in fat and on a normal diet of rat cubes. 2. Rats were trained to discriminate between vertical and horizontal striations. The minimal stripe width that could be used for discrimination was determined. 3. In bright illumination (0·7 or 4·5 ft.lamberts) both deficient and normal rats had the same ability to discriminate between black and white stripes. 4. With an illuminance of 0·002 ft.lambert, supplemented rats could discriminate as efficiently as at 0·7 ft.lambert, but deficient animals were unable to discriminate at 0·002 ft.lambert. 5. Control rats had 14% of docosahexaenoic acid in their retinal fats but the deficient rats had only 1%. 6. Deficient animals had no vitamin A stores in the liver whereas the control animals had about 190 i.u./g. 7. The visual acuity of the rats used was about 45′ of arc.     

Intracellular expression profiles measured by real-time PCR tomography in the Xenopus laevis oocyte

Real-time PCR tomography is a novel, quantitative method for measuring localized RNA expression profiles within single cells. We demonstrate its usefulness by dissecting an oocyte from Xenopus laevis into slices along its animal-vegetal axis, extracting its RNA and measuring the levels of 18 selected mRNAs by real-time RT-PCR. This identified two classes of mRNA, one preferentially located towards the animal, the other towards the vegetal pole. mRNAs within each group show comparable intracellular gradients, suggesting they are produced by similar mechanisms. The polarization is substantial, though not extreme, with around 5% of vegetal gene mRNA molecules detected at the animal pole, and around 50% of the molecules in the far most vegetal section. Most animal pole mRNAs were found in the second section from the animal pole and in the central section, which is where the nucleus is located. mRNA expression profiles did not change following in vitro fertilization and we conclude that the cortical rotation that follows fertilization has no detectable effect on intracellular mRNA gradients.     

Interactions of TolB with the translocation domain of colicin E9 require an extended TolB box

The mechanism by which enzymatic E colicins such as colicin E3 (ColE3) and ColE9 cross the outer membrane, periplasm, and cytoplasmic membrane to reach the cytoplasm and thus kill Escherichia coli cells is unique in prokaryotic biology but is poorly understood. This requires an interaction between TolB in the periplasm and three essential residues, D35, S37, and W39, of a pentapeptide sequence called the TolB box located in the N-terminal translocation domain of the enzymatic E colicins. Here we used site-directed mutagenesis to demonstrate that the TolB box sequence in ColE9 is actually larger than the pentapeptide and extends from residues 34 to 46. The affinity of the TolB box mutants for TolB was determined by surface plasmon resonance to confirm that the loss of biological activity in all except one (N44A) of the extended TolB box mutants correlates with a reduced affinity of binding to TolB. We used a PCR mutagenesis protocol to isolate residues that restored activity to the inactive ColE9 D35A, S37A, and W39A mutants. A serine residue at position 35, a threonine residue at position 37, and phenylalanine or tyrosine residues at position 39 restored biological activity of the mutant ColE9. The average area predicted to be buried upon folding (AABUF) was correlated with the activity of the variants at positions 35, 37, and 39 of the TolB box. All active variants had AABUF profiles that were similar to the wild-type residues at those positions and provided information on the size, stereochemistry, and potential folding pattern of the residues of the TolB Box.     

Gender and the active smoking and high-sensitivity C-reactive protein relation in late adolescence

C-reactive protein (CRP), smoking, and oral contraceptive (OC) use are associated with CVD risk in adults. This study examines the effect of smoking on high-sensitivity CRP (hs-CRP) levels, and the interactive effects of sex and OC use on this relationship in an adolescent cohort. A total of 1,050 adolescents (mean age 17 ± 0.25 years) from the Western Australian Pregnancy Cohort (Raine) Study had anthropometric, lifestyle, and metabolic measures recorded. The association between smoking status and log-transformed hs-CRP was analyzed using multivariable Tobit linear regression models, with adjustment for adiposity, lifestyle, and early-life confounders. A three-level variable (girls not using OCs, girls using OCs, and boys) was employed to assess the interactive effects of sex, OC use, and smoking. Smoking associated with higher hs-CRP levels in girls not using OCs (b = 0.571; P = 0.001), but not in girls using OCs (b = −0.117; P = 0.598) or in boys (b = 0.183; P = 0.2). OC use in nonsmoking girls was the strongest factor associated with higher hs-CRP levels (b = 1.189; P < 0.001). This study has demonstrated a more robust effect of smoking on hs-CRP levels in girls not using OCs compared with boys. The findings may explain why CVD risk conferred by smoking is higher in women than in men.     

A FILAMENTOUS FLOWER orthologue plays a key role in leaf patterning in opium poppy

The plant‐specific YABBY genes were initially defined by their roles in determining abaxial/adaxial cell fate in lateral organs of eudicots, and repressing meristematic genes in differentiating tissues such as leaves. In Arabidopsis thaliana FILAMENTOUS FLOWER (FIL) is also required for inflorescence and floral meristem establishment and flower development in a pathway involving the floral transition and identity genes. Here we describe the characterization of a FIL orthologue from the basal eudicot, Papaver somniferum (the opium poppy), and demonstrate a role for the gene in patterning the highly lobed leaf of the poppy. Silencing of PapsFIL using viral‐induced gene silencing resulted in leaves of reduced laminar area, more pronounced margin serration and, in some cases, leaf bifurcation. In contrast, the gene does not appear to affect the development of the flower, and these variations in function are discussed in relation to its taxonomic position as a basal eudicot and its determinate growth habit.     

Impact of a multimodal exercise program on tibial bone health in adolescents with Development Coordination Disorder: an examination of feasibility and potential efficacy

Objectives:Developmental coordination disorder (DCD) compromises bone health purportedly due to lower levels of physical activity. The potential of an exercise intervention to improve bone health parameters in adolescents with DCD has not previously been studied. This study thus aimed to determine the impact of a multimodal exercise intervention on bone health in this population at-risk of secondary osteoporosis.Methods:Twenty-eight adolescents (17 male, 11 female) aged between 12-17 years (M_age=14.1) with DCD participated in a twice weekly, 13-week generalised multimodal exercise intervention. Peripheral quantitative computed tomography scans of the tibia (4% and 66%) were performed over a six month period. Generalised estimating equations were used to examine the impact of fitness measures on bone parameters over time.Results:An overall improvement trend was observed for bone health, with significant increases at the 66% tibial site for bone mass (4.12% increase, d_cohen=0.23, p=0.010) and cortical area (5.42% increase, η² =12.09, p=0.014). Lower body fitness measures were significantly associated with improvements in bone health parameters, tempered by the degree of motor impairment.Conclusion:A multimodal exercise intervention may be effective in improving bone health of adolescents with DCD. Given the impact of motor impairments, gains may be greater over an extended period of study.