Population structure and phylogeography reveal pathways of colonization by a migratory marine reptile (Chelonia mydas) in the central and eastern Pacific

Climate, behavior, ecology, and oceanography shape patterns of biodiversity in marine faunas in the absence of obvious geographic barriers. Marine turtles are an example of highly migratory creatures with deep evolutionary lineages and complex life histories that span both terrestrial and marine environments. Previous studies have focused on the deep isolation of evolutionary lineages (>3 mya) through vicariance; however, little attention has been given to the pathways of colonization of the eastern Pacific and the processes that have shaped diversity within the most recent evolutionary time. We sequenced 770 bp of the mtDNA control region to examine the stock structure and phylogeography of 545 green turtles from eight different rookeries in the central and eastern Pacific. We found significant differentiation between the geographically separated nesting populations and identified five distinct stocks (F_ST = 0.08–0.44, P < 0.005). Central and eastern Pacific Chelonia mydas form a monophyletic group containing 3 subclades, with Hawaii more closely related to the eastern Pacific than western Pacific populations. The split between sampled central/eastern and western Pacific haplotypes was estimated at around 0.34 mya, suggesting that the Pacific region west of Hawaii has been a more formidable barrier to gene flow in C. mydas than the East Pacific Barrier. Our results suggest that the eastern Pacific was colonized from the western Pacific via the Central North Pacific and that the Revillagigedos Islands provided a stepping‐stone for radiation of green turtles from the Hawaiian Archipelago to the eastern Pacific. Our results fit with a broader paradigm that has been described for marine biodiversity, where oceanic islands, such as Hawaii and Revillagigedo, rather than being peripheral evolutionary “graveyards”, serve as sources and recipients of diversity and provide a mechanism for further radiation.     

Characterization of an apoplastic basic thaumatin-like protein from recalcitrant chestnut seeds

Mature chestnut seeds, with one of the highest moisture contents described to date, accumulate certain defensive proteins at unusually elevated levels. In this work a major 23-kDa thaumatin-like protein, termed CsTL1, has been purified from mature chestnut ( Castanea sativa ) cotyledons. Amino acid sequencing and characterization of its full-length cDNA indicate that CsTL1 is synthesized as a preprotein with a signal peptide 22 amino acids in length. The mature protein contains 16 conserved cysteine residues presumably involved in disulfide bonding and has a high isoelectric point (ca. 9). Unlike most basic pathogenesis-related (PR) proteins, mature CsTL1 is localized to the extracellular matrix, as revealed by immunoelectron microscopy studies of cotyledonary cells. The isolated protein has in vitro antifungal activity against Trichoderma viride and Fusarium oxysporum and shows strong synergistic effects with CsCh1, the most abundant chestnut cotyledon endochitinase. Moreover, both CsTL1 and CsCh1 appear to be regulated in the same manner during seed development and germination. These observations, along with the recent finding of endoglucanase activity for some TL proteins, support the notion that CsTL1 and CsCh1 are part of a complex seed defensive system against microbial growth. Another possibility is that these, and probably other seed PR proteins, have antifreeze activity. Both functions would be particularly relevant for chestnut seeds given their remarkable moisture content at maturity.     

The adaptive acid response in Mesorhizobium sp.

Mesorhizobium huakuii strain LL56 and Mesorhizobium sp. strain LL22, which nodulate Lotus glaber, developed an adaptive acid response during exponential growth upon exposure to sublethal acid conditions. The adaptive acid response was found to be dependent on the sublethal pH and the strain intrinsic acid tolerance: the lowest adaptation pH was 4.0 for strain LL56 and 5.7 for strain LL22, and the lowest pH values tolerated after adaptation were 3.0 and 4.0, respectively. Both complex and minimal medium allowed the development of the adaptive acid response, although in complex medium this response was more effective. Three low molecular weight polypeptides (LMWPs) showed increased expression in strain LL56 during the adaptation to pH 4.0. However, the adaptive acid tolerance was only partially dependent on de novo protein synthesis, and constitutive systems may play a significant role on the acid tolerance of Mesorhizobium huakuii strain LL56.     

Physical and chemical characteristics of the sediment in the estuarine region of Cananéia (SP), Brazil

Physical and chemical characteristics of sediment were analyzed at eight sampling areas in the estuarine region of Cananéia (SP), Brazil. The samples were collected in 1995 during four periods; summer, autumn, winter and spring. Total nitrogen and phosphorus concentrations, redox potential, water and organic matter percentage, sand and silt percentage and grain size were determined in six different layers of 20 cm deep columns of sediment. In general, the nutrient concentration and the percentage of organic matter decreased with depth and greater variations were observed in the first centimeter of the samples. Differences in nutrient concentration and organic matter were also observed during the study period. The highest concentrations were recorded during the rainy season (February) as a consequence of an accumulation of organic matter brought into the system by rivers and adjacent flooded areas. In general, the sediments had oxidized characteristics until the 5 or 10 cm depth in areas near the rich coastal vegetation. However, in areas open to the ocean, the entire sediment columns were almost completely oxidized.     

School racial segregation and long-term cardiovascular health among Black adults in the US: A quasi-experimental study

BackgroundCardiovascular disease (CVD) disproportionately affects Black adults in the United States. This is increasingly acknowledged to be due to inequitable distribution of health-promoting resources. One potential contributor is inequities in educational opportunities, although it is unclear what aspects of education are most salient. School racial segregation may affect cardiovascular health by increasing stress, constraining socioeconomic opportunities, and altering health behaviors. We investigated the association between school segregation and Black adults’ CVD risk.Methods and findingsWe leveraged a natural experiment created by quasi-random (i.e., arbitrary) timing of local court decisions since 1991 that released school districts from court-ordered desegregation. We used the Panel Study of Income Dynamics (PSID) (1991 to 2017), linked with district-level school segregation measures and desegregation court order status. The sample included 1,053 Black participants who ever resided in school districts that were under a court desegregation order in 1991. The exposure was mean school segregation during observed schooling years. Outcomes included several adult CVD risk factors and outcomes. We fitted standard ordinary least squares (OLS) multivariable linear regression models, then conducted instrumental variables (IV) analysis, using the proportion of schooling years spent in districts that had been released from court-ordered desegregation as an instrument. We adjusted for individual- and district-level preexposure confounders, birth year, and state fixed effects. In standard linear models, school segregation was associated with a lower probability of good self-rated health (−0.05 percentage points per SD of the segregation index; 95% CI: −0.08, −0.03; p < 0.001) and a higher probability of binge drinking (0.04 percentage points; 95% CI: 0.002, 0.07; p = 0.04) and heart disease (0.01 percentage points; 95% CI: 0.002, 0.15; p = 0.007). IV analyses also found that school segregation was associated with a lower probability of good self-rated health (−0.09 percentage points; 95% CI: −0.17, −0.02, p = 0.02) and a higher probability of binge drinking (0.17 percentage points; 95% CI: 0.04, 0.30, p = 0.008). For IV estimates, only binge drinking was robust to adjustments for multiple hypothesis testing. Limitations included self-reported outcomes and potential residual confounding and exposure misclassification.ConclusionsSchool segregation exposure in childhood may have longstanding impacts on Black adults’ cardiovascular health. Future research should replicate these analyses in larger samples and explore potential mechanisms. Given the recent rise in school segregation, this study has implications for policies and programs to address racial inequities in CVD.

Min Hee Kim and colleagues investigate the association between exposure to school racial segregation in childhood and long-term cardiovascular health among Black adults in the United States.     

Cholecystokinin Outcome on Markers of Intestinal IgA Antibody Response

Cholecystokinin 8 (CCK8) is an entero-octapeptide that participates in crosstalk with components of intestinal immunity via the CCK receptor (CCKR), but its role in modulation of the IgA response is not fully known under physiological conditions. Male eight-week-old BALB/c mice each were intraperitoneally injected once during 7 days with CCK8, devazapide (CCKR1 antagonist), L365,260 (CCKR2 antagonist) or vehicle (sham group). In intestinal lavages, total and secretory IgA (SIgA) were determined by ELISA; in lamina propria, IgA⁺ B lymphocytes and IgA⁺ plasma cells were analyzed by flow cytometry; mRNA levels of polymeric immunoglobulin receptor (pIgR) in epithelial cells and α chain, interleukins (ILs) in lamina propria cells were assessed by qRTPCR. Regarding the sham conditions, IgA⁺ plasma-cell percentage and IL-2, IL-5, IL-10 and transforming growth factor-β (TGF-β) mRNA levels were either increased by CCK8 or decreased by both CCKR antagonists. For IgA/SIgA responses, IL-4/IL-6 mRNA levels were decreased by all drugs and pIgR mRNA was increased by CCK8 and reduced by L365,260. IgA⁺ B cell percentage and α chain mRNA levels were elicited by CCK8 and L365,260. Data suggested a presumable differential role of CCK/CCKR on the IgA-response; outcome of L365,260 on the elicitation of IgA⁺ B cells and α chain mRNA needs further examination.     

A recombinant monoclonal-based Taenia antigen assay that reflects disease activity in extra-parenchymal neurocysticercosis

BackgroundAntigen tests for diagnosis and disease monitoring in some types of neurocysticercosis (NCC) are useful but access to testing has been limited by availability of proprietary reagents and/or kits.Methods/Principal findingsThree previously identified IgM-secreting hybridomas whose IgM products demonstrated specificity to Taenia solium underwent variable heavy and light chain sequencing and isotype conversion to mouse IgG. Screening of these recombinantly expressed IgG anti-Ts hybridomas, identified one (TsG10) with the highest affinity to crude Taenia antigen. TsG10 was then used as a capture antibody in a sandwich antigen detection immunoassay in combination with either a high titer polyclonal anti-Ts antibody or with biotinylated TsG10 (termed TsG10*bt). Using serum, plasma, and CSF samples from patients with active NCC and those from NCC-uninfected patients, ROC curve analyses demonstrated that the TsG10-TsG10-*bt assay achieved a 98% sensitivity and 100% specificity in detecting samples known to be antigen positive and outperformed the polyclonal based assay (sensitivity of 93% with 100% specificity). By comparing levels of Ts antigen (Ag) in paired CSF (n = 10) or plasma/serum (n = 19) samples from well-characterized patients with extra-parenchymal NCC early in infection and at the time of definitive cure, all but 2 (1 from CSF and 1 from plasma) became undetectable. There was a high degree of correlation (r = 0.98) between the Ag levels detected by this new assay and levels found by a commercial assay. Pilot studies indicate that this antigen can be detected in the urine of patients with active NCC.Conclusions/SignificanceA newly developed recombinant monoclonal antibody-based Ts Ag detection immunoassay is extremely sensitive in the detection of extra-parenchymal NCC and can be used to monitor the success of treatment in the CSF, serum/plasma and urine. The ability to produce recombinant TsG10 at scale should enable use of this antigen detection immunoassay wherever NCC is endemic.Clinical Trial RegistrationClinicalTrials.gov Identifiers: {"type":"clinical-trial","attrs":{"text":"NCT00001205","term_id":"NCT00001205"}}NCT00001205 - & {"type":"clinical-trial","attrs":{"text":"NCT00001645","term_id":"NCT00001645"}}NCT00001645.     

Patients with Alzheimer's disease show an increased content of 15 Kdalton somatostatin precursor and a lowered level of tetradecapeptide in their cerebrospinal fluid

The relative proportions of both somatostatin-14 and its precursors somatostatin-28 and the 15 Kdalton prosomatostatin were evaluated by radioimmunoassay in the cerebrospinal fluid of patients with Alzheimer's disease. It was observed that the patients have a lowered content in the tetradecapeptide somatostatin while they exhibit a significant increase in unprocessed 15 Kda precursor. These results indicate that these patients possess impaired processing mechanisms which may be responsible for the lowered content in mature somatostatin-14. These observations may provide a valuable test for the ante-mortem diagnosis of the disease. They are discussed in connection with others suggesting that Alzheimer's patients may be selectively altered in their somatostatinergic neurones of their cerebral cortex (Morrison et al. (1985) Nature 314, 90-92. Roberts et al. (1985) Nature 314, 92-94).