Stable carbon and nitrogen isotope ratios were used to define the trophic base of the infaunal suspension-feeding bivalve Cerastoderma edule (L.) living on an intertidal muddy sandflat in Marennes-Oleron Bay, France. Suspended particulate organic matter (POM) collected from adjacent marine channels had a mean 6I3C value of -22 2 * 1.1 %O (n = 19). Benthic primary producers on Ronceles-Bains tidal flats had 613C values distinct from that of the POM: microphytobenthos (-16.0 * 0.6%).the macroalgae Enteromorpha compressa (-17.6 + 2.8%), Fucus serratus (-17.4 + 2.6%0), Fucus vesiculosus(-18.5 * 1.6%), Phorphyra umbilicalis (-19.7 t 0.5%0), Ulva rigida (-14.7 + 2 0%) and the seagrass Zostera noltii (-11.1 + 1.0%). Mean 615N values of all macroalgae species ranged from 7.6 + 1.3 to 8.9 * 1.0%, while those for microphytobenthos, POM and seagrass were 5.3 + 0.8, 5.0 * 0 9 and 6.5 r 1.3%0, respectively. The mean 613C value of spat (-15.3 + 0.8%0) and juvenile cockles (-15.7 * 0.7%0) varied within a smaller range than those of 1 to 4 yr old adults (-18.2 + 1.2%). The 6I5N values of 0-group cockles (spat and juveniles) and adult cockles are similar (8.0 * 0.9%0 for 0-group and 8.4 * 1.1% for adults). The results suggest, based on the average trophic enrichment found in the literature for C and N, and the relative abundance of each food source, that there are 2 major sources of organic matter assimilated by cockles of the studied flats: microphytobenthos and POM. Seasonal variations in 613C values reflect a higher dependence of adult cockles on POM vanability while spat and juveniles are more closely Linked to microphytobenthos. The isotopic shifts indicate that the relative importance of the 2 major food sources depends on the age of the cockles and the season.
Developing
a highly efficient and ecofriendly system to produce
desired products from waste can be considered important to a sustainable
society. Here, we report for the first time high-yield production
of lycopene through metabolically engineering an extremophilic microorganism, Deinococcus radiodurans R1, from corn steep liquor
(CSL) and glycerol. First, the crtLm gene-encoding
lycopene cyclase was deleted to prevent the conversion of lycopene
to γ-carotene. Then, the crtB gene-encoding
phytoene synthase and the dxs gene-encoding 1-deoxy-d-xylulose 5-phosphate synthase were overexpressed to increase
carbon flux toward lycopene. The engineered ΔcrtLm/crtB
+
dxs
+
D. radiodurans R1 could produce 273.8 mg/L [80.7 mg/g dry cell weight (DCW)] and
373.5 mg/L (108.0 mg/g DCW) of lycopene from 10 g/L of glucose with
5 g/L of yeast extract and 9.9 g/L of glucose with 20 g/L of CSL,
respectively. Moreover, the lycopene titer and content were increased
by 26% (470.6 mg/L) and 28% (138.2 mg/g DCW), respectively, when the
carbon source was changed to glycerol. Finally, fed-batch fermentation
of the final engineered strain allowed the production of 722.2 mg/L
(203.5 mg/g DCW) of lycopene with a yield and productivity of 20.3
mg/g glycerol and 6.0 mg/L/h, respectively, from 25 g/L of CSL and
35.7 g/L of glycerol.
To date, the implications of interleukin 6 (IL-6) for immune responses in the context of Brucella infection are still unknown. In the present study, we found that Brucella abortus infection induced marked production of IL-6 in mice that was important for sufficient differentiation of CD8+ T cells, a key factor in Brucella clearance. Blocking IL-6 signaling also significantly induced serum IL-4 and IL-10, together with a decreased gamma interferon (IFN-γ) level, suggesting that IL-6 is essential for priming the T-helper (Th) 1 cell immune response during Brucella infection. The IL-6 pathway also activated the bactericidal activity of primary and cultured macrophages. Bacterial killing was markedly abrogated when IL-6 signaling was suppressed, and this phenomenon was mainly associated with decreased activity of lysosome-mediated killing. Interestingly, suppressor of cytokine signaling 3 (SOCS3) was important for regulating the IL-6-dependent anti-Brucella activity through the JAK/STAT pathway. During early infection, in the absence of SOCS3, IL-6 exhibited anti-inflammatory effects and lysosome-mediated killing inhibition; however, the increase in SOCS3 successfully shifted functional IL-6 toward proinflammatory brucellacidal activity in the late stage. Our data clearly indicate that IL-6 contributes to host resistance against B. abortus infection by controlling brucellacidal activity in macrophages and priming cellular immune responses.
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