Geographic patterns of genetic diversity in Poulsenia armata (Moraceae): implications for the theory of Pleistocene refugia and the importance of riparian forest

Abstract. Tropical forests are species-diverse communities, but we know very little about the geographical distribution of genetic diversity within a species. During the late Pleistocene, lower temperatures and rainfall reduced the distribution of tropical wet forests, and in Central America lowland species may have been limited to riparian habitats. Approximately 12,000 years bp , temperature and rainfall increased in Central America, the distribution of wet forest species expanded, and today the distribution of some species extends into southern Mexico. The distribution of genetic diversity, based on RAPD markers, among ten populations of Poulsenia armata (Miq.) Standl. (Moraceae) suggests that these populations did not originate from a single refugium or region in the late Pleistocene. The Central American populations had high genetic diversity and unique bands giving support to the hypothesis that populations of P. armata occurred in Central American during the late Pleistocene. The majority of genetic diversity was partitioned among populations and there was no geographical relationship among populations, suggesting that these populations were isolated for a long period and there has been little gene flow. Populations of P. armata may have persisted in riparian zones along the Caribbean coast during the late Pleistocene. Given that riparian forest can support high levels of biodiversity in ecological time, and they have played an important role during periods of climate change over geological time, their conservation is of utmost importance particularly with the threat of a rapid shift in climatic patterns.     

Isolation and identification of mucinolytic actinomycetes

Biochemical and physiological tests, and 16S rRNA gene sequences, were used to classify nine Actinomycete strains isolated from soil and sand samples in Thailand. These strains were isolated based on their ability to readily degrade mucin glycoproteins. A turbidometric based mucinolytic assay was developed to confirm this. In addition all strains showed significant production of proteases. Phylogenetic analysis of the strains revealed that from the nine isolated Actinomycete strains eight were closely related to Streptomyces species and one was identified as belonging to the genus Kitasatospora. The biochemical and physiological tests performed identified two strain pairs that were similar (with only 3.9% difference observed) and this was in accordance with the phylogenetic results obtained. The remaining strains were distinct from each other, with the soil-isolated strains forming a separate clade to the sand-isolated strains in the inferred phylogenetic trees. The isolated mucinolytic Actinomycete strains will be the subject of further investigations into their proteolytic and glycosidic activity. Mucin degrading enzymes such as these are studied for their potential to be used for the development of a drug delivery system.     

Maternal corticotropin-releasing hormone levels during pregnancy and offspring adiposity

Objective: Animal models suggest that fetal exposure to glucocorticoids can program adiposity, especially central adiposity, later in life. We examined associations of maternal corticotropin‐releasing hormone (CRH) levels in the late 2nd trimester of pregnancy, a marker of fetal glucocorticoid exposure, with child adiposity at age 3 years. Research Methods and Procedures: We analyzed data from 199 participants in Project Viva, a prospective cohort study of pregnant women and their children, At age 3 years, the main outcomes were age‐sex‐specific BMI z score and the sum of subscapular (SS) and triceps (TR) skinfold thicknesses to represent overall adiposity, and ratio of SS to TR (SS:TR) to represent central adiposity. Results: Mean (standard deviation) maternal 2nd trimester log CRH was 4.94 (0.56) pg/mL. At age 3, mean (standard deviation) for BMI z score was 0.52 (1.02); for SS + TR, 16.51 (3.94) mm; and for SS:TR, 0.67 (0.17). Log CRH was mildly inversely correlated with birth weight (r = ?0.08), chiefly because of its association with length of gestation (r = ?0.21) rather than fetal growth (r = ?0.004). After adjustment for sociodemographic factors, maternal smoking, BMI, and gestational weight gain, fetal growth, length of gestation, breastfeeding duration, and (for SS:TR only) child's 3‐year BMI, each increment of 1 unit of log CRH was associated with a reduction in BMI z score [?0.43; 95% confidence interval (CI), ?0.73, ?0.14; p = 0.004] and possible reduction in SS + TR (?1.10; 95% CI, ?2.33, 0.14; p = 0.08). In contrast, log CRH was associated with higher SS:TR (0.07; 95% CI, 0.02, 0.13; p = 0.007). Discussion: Fetal exposure to glucocorticoids, although associated with an overall decrease in body size, may cause an increase in central adiposity.     

The N-terminus of TDP-43 promotes its oligomerization and enhances DNA binding affinity

TDP-43 is a DNA/RNA-binding protein associated with different neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD-U). Here, the structural and physical properties of the N-terminus on TDP-43 have been carefully characterized through a combination of nuclear magnetic resonance (NMR), circular dichroism (CD) and fluorescence anisotropy studies. We demonstrate for the first time the importance of the N-terminus in promoting TDP-43 oligomerization and enhancing its DNA-binding affinity. An unidentified structural domain in the N-terminus is also disclosed. Our findings provide insights into the N-terminal domain function of TDP-43.     

Inhibition of neuronal cell death after retinoic acid-induced down-regulation of P2X7 nucleotide receptor expression

Apoptosis is a major mechanism for cell death in the nervous system during development. P2X₇ nucleotide receptors are ionotropic ATP receptors that mediate cell death under pathological conditions. We developed an in vitro protocol to investigate the expression and functional responses of P2X₇ nucleotide receptors during retinoic acid (RA)-induced neuronal differentiation of human SH-SY5Y neuroblastoma cells. Neuronal differentiation was examined measuring cellular growth arrest and neuritic processes elongation. We found that SH-SY5Y cells treated for 5 days with RA under low serum content exhibited a neuron-like phenotype with neurites extending more than twice the length of the cell body and cell growth arrest. Concurrently, we detected the abolishment of intracellular-free calcium mobilization and the down-regulation of P2X₇ nucleotide receptor protein expression that protected differentiated cells from neuronal cell death and reduced caspase-3 cleavage-induced by P2X₇ nucleotide receptor agonist. The role of P2X₇ nucleotide receptors in neuronal death was established by selectively antagonizing the receptor with KN-62 prior to its activation. We assessed the involvement of protein kinases and found that p38 signaling was activated in undifferentiated after nucleotide stimulation, but abolished by the differentiating RA pretreatment. Importantly, P2X₇ receptor-induced caspase-3 cleavage was blocked by the p38 protein kinase specific inhibitor PD169316. Taken together, our results suggest that RA treatment of human SH-SY5Y cells leads to decreased P2X₇ nucleotide receptor protein expression thus protecting differentiated cells from extracellular nucleotide-induced neuronal death, and p38 signaling pathway is critically involved in this protection of RA-differentiated cells.     

Evaluating the impact of point‐ of‐care decision support tools in improving diagnosis of obese children in primary care

Objective:

The purpose of this quasi‐experimental study was to examine the effect of a computerized point‐of‐care alert with clinical decision support on the rates of diagnosis of childhood obesity in a multisite group practice in Massachusetts; Cambridge Health Alliance (CHA) which implemented an alert, relative to a separate group practice, Harvard Vanguard Medical Associates (HVMA), that did not.

Design and Methods:

Height and weight data from 19,466 children of 2‐18 years with 34,908 well‐child care visits in CHA and 123,446 children with 282,271 visits in HVMA between 2006 and 2008 were collected. The alert and decision support tool was activated for CHA patients with an age‐ and sex‐specific body mass index of ≥95th percentile. The main outcome measure was documentation of an International Classification of Diseases, Ninth Revision [ICD‐9] code for obesity before and after implementation of the alert at CHA in 2007.

Results:

Among obese children, the adjusted rate of an ICD‐9 diagnosis of obesity increased from 2006‐2007 to 2008 significantly more at CHA than at HVMA (P < 0.001 for time‐by‐provider group interaction). In 2006‐2007, the rate of ICD‐9 diagnosis of obesity was significantly lower at CHA than at HVMA (adjusted odds ratio [OR]: 0.57; 95% confidence interval [CI]: 0.52‐0.62); but by 2008 was significantly higher at CHA than HVMA (adjusted OR: 1.25; 95% CI: 1.14‐1.38).

Conclusion:

A point‐of‐care alert was effective in improving obesity diagnosis in a multisite group practice, relative to a separate group practice that did not adopt an alert. Clinical decision support tools could help improve obesity diagnosis in pediatric primary care.     

Correlates of Participation in a Pediatric Primary Care‐Based Obesity Prevention Intervention

The purpose of this study was to examine the correlates of participation in a childhood obesity prevention trial. We sampled parents of children recruited to participate in a randomized controlled trial. Eligible children were 2.0–6.9 years with BMI ≥95th percentile or 85th to <95th percentile if at least one parent was overweight. We attempted contact with parents of children who were potentially eligible. We recruited 475 parents via telephone following an introductory letter. We also interviewed 329 parents who refused participation. Parents who refused participation (n = 329) did not differ from those who participated (n = 475) by number of children at home (OR 0.94 per child; 95% CI: 0.77–1.15) or by child age (OR 1.07 per year; 95% CI: 0.95–1.20) or sex (OR 1.06 for females vs. males; 95% CI: 0.80–1.41). After multivariate adjustment, parents who were college graduates vs. <college graduates were less likely to participate (OR 0.62; 95% CI: 0.46–0.83). In addition, parents were less likely (OR 0.41; 95% CI: 0.31–0.56) to participate if their child was overweight vs. obese. Among the 115 refusers with obese children, 21% cited as a reason for refusal that their children did not have a weight problem, vs. 30% among the 214 refusers with overweight children. In conclusion, parents of preschool‐age children with a BMI 85–95th%ile are less likely to have their children participate in an obesity prevention trial than parents of children with BMI >95th%ile. One reason appears to be that they less frequently consider their children to have a weight problem.