B cell activity is impaired in human and mouse obesity and is responsive to an essential fatty acid upon murine influenza infection

Obesity is associated with increased risk for infections and poor responses to vaccinations, which may be due to compromised B cell function. However, there is limited information about the influence of obesity on B cell function and underlying factors that modulate B cell responses. Therefore, we studied B cell cytokine secretion and/or Ab production across obesity models. In obese humans, B cell IL-6 secretion was lowered and IgM levels were elevated upon ex vivo anti-BCR/TLR9 stimulation. In murine obesity induced by a high fat diet, ex vivo IgM and IgG were elevated with unstimulated B cells. Furthermore, the high fat diet lowered bone marrow B cell frequency accompanied by diminished transcripts of early lymphoid commitment markers. Murine B cell responses were subsequently investigated upon influenza A/Puerto Rico/8/34 infection using a Western diet model in the absence or presence of docosahexaenoic acid (DHA). DHA, an essential fatty acid with immunomodulatory properties, was tested because its plasma levels are lowered in obesity. Relative to controls, mice consuming theWestern diet had diminished Ab titers whereas theWestern diet plus DHA improved titers. Mechanistically, DHA did not directly target B cells to elevate Ab levels. Instead, DHA increased the concentration of the downstream specialized proresolving lipid mediators (SPMs) 14-hydroxydocosahexaenoic acid, 17-hydroxydocosahexaenoic acid, and protectin DX. All three SPMs were found to be effective in elevating murine Ab levels upon influenza infection. Collectively, the results demonstrate that B cell responses are impaired across human and mouse obesity models and show that essential fatty acid status is a factor influencing humoral immunity, potentially through an SPM-mediated mechanism

Cell wall compositional differences between mealy and non-mealy 'Forelle' pear during ripening

Mealiness of 'Forelle' pear during ripening is a problem for the South African fruit export industry. The aim of this work was to investigate differences in cell wall polysaccharides between mealy and non-mealy 'Forelle' pears. Fruit were harvested at optimum maturity (62.8 N), cold stored for 3 to 21 weeks at-0.5°C, and ripened at 15°C for 0, 4, 7 and 11 days during which samples were taken for cell wall analysis. Only dates where mealiness occurred were used for cell wall analysis. Cell walls (CW) were extracted and de-starched with 90% DMSO and uronic acid (UA) content measured. Samples were sequentially extracted with water, CDTA, Na2CO3, 1 M KOH and 4 M KOH to determine differences in binding strength of the cell wall constituents between mealy and non-mealy tissues. UA content was measured for each of these fractions. The UA content of the water soluble fraction was lower in mealy tissues after 6 weeks of cold storage plus 11 days of ripening, and 9 weeks of cold storage plus 7 and 11 days of ripening. In the CDTA soluble fraction, UA content was also lower in mealy tissues of fruit that were cold stored for 6 weeks and ripened for 11 days. Mealy and non-mealy cell walls of 'Forelle' showed compositional differences. The lower water soluble pectin and CDTA soluble pectin without a substantial increase in the Na2CO 3 soluble pectin for mealy tissues suggests a more broken down cell wall in mealy tissues.Conference Pape

Mealiness development in ‘Forelle’ pears (Pyrus communis L.) Is Influenced by cell size

Mealiness in ‘Forelle’ pear is a textural disorder characterised by dry and soft texture deterioration, occurring mostly in fruit stored for less than the mandatory 12 weeks at -0.5°C. This study investigated the role of cell size in the development of mealiness in ‘Forelle’ pear. Variations in cell sizes among fruit were incited by applying plant growth regulators: 2,4-D amine, prohexadione-Ca, gibberellin 4+7 and forchlorfenuron at different stages following bloom during the 2011 season. In 2012, hand thinning of fruit was done on blossom clusters, leaving fruit from the “king” blossom and one fruit from a smaller blossom. Cell size and other cell characteristics were examined on dried sections of the fruit cortex using scanning electron microscopy. Treatments that induced fruit with larger cells had higher mealiness percentage. Forchlorfenuron and its combination with gibberellin 4+7 produced fruit with significantly (P=0.038) higher mealiness percentage. 2,4-D amine had the least mealiness percentage compared to other treatments. Cell volume and cell diameter exhibited a positive linear relationship with mealiness percentage. Examination of histological differences between mealy and non-mealy fruit revealed differences in size of intercellular spaces with mealy fruit having larger spaces. The results from this study suggest that cell size and size of intercellular spaces are linked to the development of mealiness

TRANSPIRATION RATES AND LEAF BOUNDARY LAYER PARAMETERS FOR PEANUT ANALYZED WITH THE TWO-DIMENSIONAL MODEL 2DLEAF

Rates of leaf transpiration and photosynthesis are both affected by the thickness of the boundary layer (BL) and by the rates at which gases diffuse through it. These BL properties are currently impossible to measure and must be estimated by using models in conjunction with measured rates of transpiration. Transpiration rates and BL for two Argentine peanut (Arachis hypogaea L.) cultivars, Florman INTA, Virginia type, and Manfredi 393 INTA, Spanish type, were studied with the two-dimensional model 2DLEAF which accounts for leaf anatomy, i.e. for leaf internal structure and stomatal density. Measurements on leaf cross-sections and leaf surface images demonstrated a significant difference between two cultivars. Published transpiration rates for peanut of Virginia and Spanish types measured in controlled environment and field conditions were used to determine two parameters of the leaf BL, its thickness, d, and the ratio of diffusion coefficients in the BL and in the intercellular space, B. Both parameters were different for two cultivars. Transpiration rate was presented (a) as a function of BL parameters d and B with four empirical parameters which depended on cultivar and stomatal aperture, and (b) as a function of stomatal aperture and d. Dependence (b) showed that the transpiration rate of Manfredi 393 INTA is higher than that of Florman at the same environmental conditions, and that this is completely due to the difference in leaf anatomy. It was shown that the values of BL thickness, d, grow with increasing stomatal aperture. For amphystomatous leaves of peanut, two empirical parameters, d and B, are necessary and sufficient to quantitatively describe the effect of the BL on transpiration

Organic-rich sedimentation in the South Pacific Ocean associated with Late Paleocene climatic cooling

A distinctive organic-rich marine mudstone of Late Paleocene age occurs in most of New Zealand's sedimentary basins and has been identified as a potential source rock for oil and gas. Identified as the Waipawa Formation in the East Coast Basin and the Tartan Formation in the Great South and Canterbury Basins, the unit is a relatively uniform massive mudstone that varies greatly in thickness (2–70 m) and grades laterally into distinctive facies equivalents, notably greensand and a thin-bedded siliceous mudstone. All these facies are characterised by relatively high TOC (0.5–10 wt.%) and 13C enrichment (δ13CTOC N −24‰), and we refer to them collectively as “Waipawa organofacies”. Our detailed stratigraphic and geochemical studies refine the age (58.7 to 59.4 Ma), distribution and nature of the Waipawa organofacies. We have determined that deposition occurred in continental margin settings throughout much of the southwest Pacific under cool, dysoxic conditions associated with a significant influx of terrestrial organic matter, high marine productivity, a global fall in sea level, and a regional unconformity across shallow and deep marine settings. The combination of cool temperatures, lowered sea level and bathyal erosion suggests that deposition was linked to short-lived growth of an Antarctic ice sheet in the earliest Late Paleocene (~59 Ma)

Organic-rich sedimentation in the South Pacific Ocean associated with Late Paleocene climatic cooling

A distinctive organic-rich marine mudstone of Late Paleocene age occurs in most of New Zealand's sedimentary basins and has been identified as a potential source rock for oil and gas. Identified as the Waipawa Formation in the East Coast Basin and the Tartan Formation in the Great South and Canterbury Basins, the unit is a relatively uniform massive mudstone that varies greatly in thickness (2–70 m) and grades laterally into distinctive facies equivalents, notably greensand and a thin-bedded siliceous mudstone. All these facies are characterised by relatively high TOC (0.5–10 wt.%) and 13C enrichment (δ13CTOC N −24‰), and we refer to them collectively as “Waipawa organofacies”. Our detailed stratigraphic and geochemical studies refine the age (58.7 to 59.4 Ma), distribution and nature of the Waipawa organofacies. We have determined that deposition occurred in continental margin settings throughout much of the southwest Pacific under cool, dysoxic conditions associated with a significant influx of terrestrial organic matter, high marine productivity, a global fall in sea level, and a regional unconformity across shallow and deep marine settings. The combination of cool temperatures, lowered sea level and bathyal erosion suggests that deposition was linked to short-lived growth of an Antarctic ice sheet in the earliest Late Paleocene (~59 Ma)