Expression of a synthetic E. coli heat-labile enterotoxin B sub-unit (LT-B) in maize

We have produced the B subunit of the enterotoxigenic Escherichia coli (ETEC) heat-labile enterotoxin (LT-B) in transgenic maize seed. LT-B is a model antigen that induces a strong immune response upon oral administration and enhances immune responses to conjugated and co-administered antigens. Using a synthetic LT-B gene with optimized codon sequence, we examined the role of promoters and the SEKDEL endoplasmic reticulum retention motif in LT-B accumulation in callus and in kernels. Two promoters, the constitutive CaMV 35S promoter and the maize 27 kDa gamma zein promoter, which directs endosperm-specific gene expression in maize kernels, regulated LT-B expression. Ganglioside-dependent ELISA analysis showed that using the constitutive promoter, maximum LT-B level detected in callus was 0.04% LT-B in total aqueous-extractable protein (TAEP) and 0.01% in R1 kernels of transgenic plants. Using the gamma zein promoter, LT-B accumulation reached 0.07% in R1 kernels. The SEKDEL resulted in increased LT-B levels when combined with the gamma zein promoter. We monitored LT-B levels under greenhouse and field conditions over three generations. Significant variability in gene expression was observed between transgenic events, and between plants within the same event. A maximum of 0.3% LT-B in TAEP was measured in R3 seed of a transgenic line carrying CaMV 35S promoter/LT-B construct. In R3 seed of a transgenic line carrying the gamma zein promoter/LT-B construct, up to 3.7% LT-B in TAEP could be detected. We concluded that maize seed can be used as a production system for functional antigens

Agrobacterium tumefaciens-Mediated Transformation of Maize Embryos Using a Standard Binary Vector System

We have achieved routine transformation of maize (Zea mays) using an Agrobacterium tumefaciensstandard binary (non-super binary) vector system. Immature zygotic embryos of the hybrid line Hi II were infected with A. tumefaciens strain EHA101 harboring a standard binary vector and cocultivated in the presence of 400 mg L−1 l-cysteine. Inclusion of l-cysteine in cocultivation medium lead to an improvement in transient β-glucuronidase expression observed in targeted cells and a significant increase in stable transformation efficiency, but was associated with a decrease in embryo response after cocultivation. The average stable transformation efficiency (no. of bialaphos-resistant events recovered per 100 embryos infected) of the present protocol was 5.5%. Southern-blot and progeny analyses confirmed the integration, expression, and inheritance of the bar andgustransgenes in R0, R1, and R2 generations of transgenic events. To our knowledge, this represents the first report in which fertile, stable transgenic maize has been routinely produced using an A. tumefaciensstandard binary vector system

The Neutral Hydrogen Properties of Galaxies in Gas-rich Groups

We present an analysis of the integrated neutral hydrogen (Hi) properties for 27 galaxies within nine low mass, gas-rich, late-type dominated groups which we denote \Choirs". We find that majority of the central Choir galaxies have average Hi content: they have a normal gas-mass fraction with respect to isolated galaxies of the same stellar mass. In contrast, we find more satellite galaxies with a lower gas-mass fraction than isolated galaxies of the same stellar mass. A likely reason for the lower gas content in these galaxies is tidal stripping. Both the specific star formation rate and the star formation efficiency of the central group galaxies are similar to galaxies in isolation. The Choir satellite galaxies have similar specific star formation rate as galaxies in isolation, therefore satellites that exhibit a higher star formation efficiency simply owe it to their lower gas-mass fractions. We find that the most Hi massive galaxies have the largest Hi discs and fall neatly onto the Hi size-mass relation, while outliers are galaxies that are experiencing interactions. We find that high specific angular momentum could be a reason for galaxies to retain the large fraction of Hi gas in their discs. This shows that for the Choir groups with no evidence of interactions, as well as those with traces of minor mergers, the internal galaxy properties dominate over the effects of residing in a group. The probed galaxy properties strengthen evidence that the Choir groups represent the early stages of group assembly

Near-identical star formation rate densities from Hα and FUV at redshift zero

For the first time both Hα and far-ultraviolet (FUV) observations from an Hɪ-selected sample are used to determine the dust-corrected star formation rate density (SFRD: ṗ) in the local Universe. Applying the two star formation rate indicators on 294 local galaxies, we determine log(ṗ Hα) = -1.168 +0.13 -0.05 [M⊙yr^-1 Mpc^-3] and log(ṗ FUV) = -1.171 +0.12 -0.13 [M⊙yr^-1 Mpc^-3]. These values are derived from scaling Hα and FUV observations to the Hɪ mass function. Galaxies were selected to uniformly sample the full Hɪ mass (MHɪ) range of the Hɪ Parkes All-Sky Survey (MHɪ ~ 10^7 to ~10^10.7 M⊙). The approach leads to relatively larger sampling of dwarf galaxies compared to optically selected surveys. The low Hɪ mass, low luminosity, and low surface brightness galaxy populations have, on average, lower Hα/FUV flux ratios than the remaining galaxy populations, consistent with the earlier results of Meurer. The near-identical Hα- and FUV-derived SFRD values arise with the low Hα/FUV flux ratios of some galaxies being offset by enhanced Hα from the brightest and high mass galaxy populations. Our findings confirm the necessity to fully sample the Hɪ mass range for a complete census of local star formation to include lower stellar mass galaxies which dominate the local Universe.Partial funding for the SINGG and SUNGG surveys came from NASA grants NAG5-13083 (LTSA program), GALEX GI04-0105-0009 (NASA GALEX Guest Investigator grant), and NNX09AF85G (GALEX archival grant) to GR Meurer

Pion and kaon structure at the electron-ion collider

Understanding the origin and dynamics of hadron structure and in turn that of atomic nuclei is a central goal of nuclear physics. This challenge entails the questions of how does the roughly 1GeV mass-scale that characterizes atomic nuclei appear; why does it have the observed value; and, enigmatically, why are the composite Nambu-Goldstone (NG) bosons in quantum chromodynamics (QCD) abnormally light in comparison? In this perspective, we provide an analysis of the mass budget of the pion and proton in QCD; discuss the special role of the kaon, which lies near the boundary between dominance of strong and Higgs mass-generation mechanisms; and explain the need for a coherent effort in QCD phenomenology and continuum calculations, in exa-scale computing as provided by lattice QCD, and in experiments to make progress in understanding the origins of hadron masses and the distribution of that mass within them. We compare the unique capabilities foreseen at the electron-ion collider (EIC) with those at the hadron-electron ring accelerator (HERA), the only previous electron-proton collider; and describe five key experimental measurements, enabled by the EIC and aimed at delivering fundamental insights that will generate concrete answers to the questions of how mass and structure arise in the pion and kaon, the Standard Model's NG modes, whose surprisingly low mass is critical to the evolution of our Universe

Expression of a synthetic E. coli heat-labile enterotoxin B sub-unit (LT-B) in maize

We have produced the B subunit of the enterotoxigenic Escherichia coli (ETEC) heat-labile enterotoxin (LT-B) in transgenic maize seed. LT-B is a model antigen that induces a strong immune response upon oral administration and enhances immune responses to conjugated and co-administered antigens. Using a synthetic LT-B gene with optimized codon sequence, we examined the role of promoters and the SEKDEL endoplasmic reticulum retention motif in LT-B accumulation in callus and in kernels. Two promoters, the constitutive CaMV 35S promoter and the maize 27 kDa gamma zein promoter, which directs endosperm-specific gene expression in maize kernels, regulated LT-B expression. Ganglioside-dependent ELISA analysis showed that using the constitutive promoter, maximum LT-B level detected in callus was 0.04% LT-B in total aqueous-extractable protein (TAEP) and 0.01% in R1 kernels of transgenic plants. Using the gamma zein promoter, LT-B accumulation reached 0.07% in R1 kernels. The SEKDEL resulted in increased LT-B levels when combined with the gamma zein promoter. We monitored LT-B levels under greenhouse and field conditions over three generations. Significant variability in gene expression was observed between transgenic events, and between plants within the same event. A maximum of 0.3% LT-B in TAEP was measured in R3 seed of a transgenic line carrying CaMV 35S promoter/LT-B construct. In R3 seed of a transgenic line carrying the gamma zein promoter/LT-B construct, up to 3.7% LT-B in TAEP could be detected. We concluded that maize seed can be used as a production system for functional antigens.This article is published as Chikwamba, Rachel, Jennifer McMurray, Huixia Shou, Bronwyn Frame, Sue Ellen Pegg, Paul Scott, Hugh Mason, and Kan Wang. "Expression of a synthetic E. coli heat-labile enterotoxin B sub-unit (LT-B) in maize." Molecular breeding 10, no. 4 (2002): 253-265.</p

Agrobacterium tumefaciens-Mediated Transformation of Maize Embryos Using a Standard Binary Vector System

We have achieved routine transformation of maize (Zea mays) using an Agrobacterium tumefaciensstandard binary (non-super binary) vector system. Immature zygotic embryos of the hybrid line Hi II were infected with A. tumefaciens strain EHA101 harboring a standard binary vector and cocultivated in the presence of 400 mg L−1 l-cysteine. Inclusion of l-cysteine in cocultivation medium lead to an improvement in transient β-glucuronidase expression observed in targeted cells and a significant increase in stable transformation efficiency, but was associated with a decrease in embryo response after cocultivation. The average stable transformation efficiency (no. of bialaphos-resistant events recovered per 100 embryos infected) of the present protocol was 5.5%. Southern-blot and progeny analyses confirmed the integration, expression, and inheritance of the bar andgustransgenes in R0, R1, and R2 generations of transgenic events. To our knowledge, this represents the first report in which fertile, stable transgenic maize has been routinely produced using an A. tumefaciensstandard binary vector system.This article is published as Frame, Bronwyn R., Huixia Shou, Rachel K. Chikwamba, Zhanyuan Zhang, Chengbin Xiang, Tina M. Fonger, Sue Ellen K. Pegg et al. "Agrobacterium tumefaciens-mediated transformation of maize embryos using a standard binary vector system." Plant physiology 129, no. 1 (2002): 13-22. doi: 10.1104/pp.000653. Posted with permission.</p

The Neutral Hydrogen Properties of Galaxies in Gas-rich Groups

We present an analysis of the integrated neutral hydrogen (Hi) properties for 27 galaxies within nine low mass, gas-rich, late-type dominated groups which we denote \Choirs". We find that majority of the central Choir galaxies have average Hi content: they have a normal gas-mass fraction with respect to isolated galaxies of the same stellar mass. In contrast, we find more satellite galaxies with a lower gas-mass fraction than isolated galaxies of the same stellar mass. A likely reason for the lower gas content in these galaxies is tidal stripping. Both the specific star formation rate and the star formation efficiency of the central group galaxies are similar to galaxies in isolation. The Choir satellite galaxies have similar specific star formation rate as galaxies in isolation, therefore satellites that exhibit a higher star formation efficiency simply owe it to their lower gas-mass fractions. We find that the most Hi massive galaxies have the largest Hi discs and fall neatly onto the Hi size-mass relation, while outliers are galaxies that are experiencing interactions. We find that high specific angular momentum could be a reason for galaxies to retain the large fraction of Hi gas in their discs. This shows that for the Choir groups with no evidence of interactions, as well as those with traces of minor mergers, the internal galaxy properties dominate over the effects of residing in a group. The probed galaxy properties strengthen evidence that the Choir groups represent the early stages of group assembly

Erratum: Choirs, HI galaxy groups: Catalogue and detection of star-forming dwarf group members (vol 433, pg 543, 2013)

The paper 'Choirs, HI galaxy groups: catalogue and detection of star-forming dwarf group members' was published in MNRAS 433(1), 543 559 (Sweet et al. 2013). Two methods for calculating the H I deficiency parameter were presented in Section 3.7. For method (1) there was an error in the transformation used to scale our Survey for Ionization in Neutral Gas Galaxies (Meurer et al. 2006) R-band (AB) magnitudes (MagRAB) to the SuperCosmos magnitudes (MagRSC) on which Denes, Kilborn &Koribalski (2014) was based. The transformation should be MagRSC = -8.52 + 0.63MagRAB. We note that Denes et al. ( 2014) subsequently presented an updated, slightly different R-band scaling relation, which does not affect our results. In Fig. 1 we show the replacement H I deficiency figure. Methods (1) (upper panel) and (2) (lower panel, scaling from H a luminosity and R-band surface brightness) are now in closer agreement. Our main previous finding is unchanged: the Choir groups are not significantly HI-deficient in either method for calculating HI deficiency. HIPASS J1059-09 is now HI deficient in both methods, though not at a significant level. As before, HIPASS J1403-06 was found to be marginally HI deficient by method (2) and not method (1), and is likely dominated by high H a equivalent width starbursting galaxies. We thank Robert Dzud zar for discovering the error