Systematic review of the “Chromodoris quadricolor group” of East Africa,with descriptions of two new species of the genus Chromodoris Alder & Hancock, 1855 (Heterobranchia,Nudibranchia)

The similarities and variations in nudibranch species of the “Chromodoris quadricolor group” (Heterobranchia, Nudibranchia) have historically created identification problems among both nudibranch enthusiasts and experts. In this study, we combine molecular genetic analyses using one nuclear gene (histone h3) and two mitochondrial genes (cytochrome c oxidase subunit I and ribosomal 16S RNA) with morphological data to ameliorate the identification of specimens from this complex in East Africa. We include a detailed examination of polymorphisms within the group. As a result, Chromodoris boucheti is synonymized with Chromodoris lochi, and two new species are described, Chromodoris celinae sp. nov. and Chromodoris helium sp. nov. Chromodoris celinae sp. nov. is a common shallow water species that was previously misidentified as C. hamiltoni. Chromodoris helium sp. nov. is a species that appears to be restricted to depths below 30 m. This study agrees with previous research indicating the recent divergence of the genus Chromodoris.     

Targeted purification development enabled by computational biophysical modeling

Chromatographic and non‐chromatographic purification of biopharmaceuticals depend on the interactions between protein molecules and a solid–liquid interface. These interactions are dominated by the protein–surface properties, which are a function of protein sequence, structure, and dynamics. In addition, protein–surface properties are critical for in vivo recognition and activation, thus, purification strategies should strive to preserve structural integrity and retain desired pharmacological efficacy. Other factors such as surface diffusion, pore diffusion, and film mass transfer can impact chromatographic separation and resin design. The key factors that impact non‐chromatographic separations (e.g., solubility, ligand affinity, charges and hydrophobic clusters, and molecular dynamics) are readily amenable to computational modeling and can enhance the understanding of protein chromatographic. Previously published studies have used computational methods such as quantitative structure–activity relationship (QSAR) or quantitative structure–property relationship (QSPR) to identify and rank order affinity ligands based on their potential to effectively bind and separate a desired biopharmaceutical from host cell protein (HCP) and other impurities. The challenge in the application of such an approach is to discern key yet subtle differences in ligands and proteins that influence biologics purification. Using a relatively small molecular weight protein (insulin), this research overcame limitations of previous modeling efforts by utilizing atomic level detail for the modeling of protein–ligand interactions, effectively leveraging and extending previous research on drug target discovery. These principles were applied to the purification of different commercially available insulin variants. The ability of these computational models to correlate directionally with empirical observation is demonstrated for several insulin systems over a range of purification challenges including resolution of subtle product variants (amino acid misincorporations). Broader application of this methodology in bioprocess development may enhance and speed the development of a robust purification platform. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 31:154–164, 2015     

Lethal and sub-lethal effects of UVB on juvenile Biomphalaria glabrata (Mollusca: Pulmonata)

Although Schistosoma mansoni occurs mainly in the tropics, where intense levels of solar radiation are present, the impact of ultraviolet (UV) light on schistosome transmission is not known. The purpose of this study was to investigate potential effects of UVB (290-320nm) on juvenile Biomphalaria glabrata, the snail intermediate host of S. mansoni. Albino and wild-type snails were exposed to doses of UVB from UV-fluorescent lamps, and the following were measured: survival, photoreactivation (light-mediated DNA repair), effects on feeding behavior, and morphological tissue abnormalities. Irradiation with UVB is lethal to B. glabrata in a dose-dependent manner. Exposure to white light subsequent to UVB irradiation enhances survival, probably by photoreactivation. The shell offers some, but not complete, protection. Experiments in which UVB transmittance through the shell was blocked with black nail polish suggest that injury to both exposed (headfoot) and shell-enclosed (mantle and visceral mass) tissues contributes to mortality in lethally irradiated snails. Wild-type (pigmented) snails are less susceptible to lethal effects of UVB than albino snails, and they may be more capable of photoreactivation. UVB exposure inhibits snail feeding behavior, and causes tentacle forks and growths on the headfoot. Thus, UVB may influence the life cycle of S. mansoni by both lethal and sub-lethal damage to the snail intermediate host. However, the ability of snails to photoreactivate may mitigate these effects.     

Influence of environmental and genetic factors linked to celiac disease risk on infant gut colonization by Bacteroides species

Celiac disease (CD) is an immune-mediated enteropathy involving genetic and environmental factors whose interaction might influence disease risk. The aim of this study was to determine the effects of milk-feeding practices and the HLA-DQ genotype on intestinal colonization of Bacteroides species in infants at risk of CD development. This study included 75 full-term newborns with at least one first-degree relative suffering from CD. Infants were classified according to milk-feeding practice (breast-feeding or formula feeding) and HLA-DQ genotype (high or low genetic risk). Stools were analyzed at 7 days, 1 month, and 4 months by PCR and denaturing gradient gel electrophoresis (DGGE). The Bacteroides species diversity index was higher in formula-fed infants than in breast-fed infants. Breast-fed infants showed a higher prevalence of Bacteroides uniformis at 1 and 4 months of age, while formula-fed infants had a higher prevalence of B. intestinalis at all sampling times, of B. caccae at 7 days and 4 months, and of B. plebeius at 4 months. Infants with high genetic risk showed a higher prevalence of B. vulgatus, while those with low genetic risk showed a higher prevalence of B. ovatus, B. plebeius, and B. uniformis. Among breast-fed infants, the prevalence of B. uniformis was higher in those with low genetic risk than in those with high genetic risk. Among formula-fed infants, the prevalence of B. ovatus and B. plebeius was increased in those with low genetic risk, while the prevalence of B. vulgatus was higher in those with high genetic risk. The results indicate that both the type of milk feeding and the HLA-DQ genotype influence the colonization process of Bacteroides species, and possibly the disease risk.     

At‐line process analytical technology (PAT) for more efficient scale up of biopharmaceutical microfiltration unit operations

Tangential flow microfiltration (MF) is a cost‐effective and robust bioprocess separation technique, but successful full scale implementation is hindered by the empirical, trial‐and‐error nature of scale‐up. We present an integrated approach leveraging at‐line process analytical technology (PAT) and mass balance based modeling to de‐risk MF scale‐up. Chromatography‐based PAT was employed to improve the consistency of an MF step that had been a bottleneck in the process used to manufacture a therapeutic protein. A 10‐min reverse phase ultra high performance liquid chromatography (RP‐UPLC) assay was developed to provide at‐line monitoring of protein concentration. The method was successfully validated and method performance was comparable to previously validated methods. The PAT tool revealed areas of divergence from a mass balance‐based model, highlighting specific opportunities for process improvement. Adjustment of appropriate process controls led to improved operability and significantly increased yield, providing a successful example of PAT deployment in the downstream purification of a therapeutic protein. The general approach presented here should be broadly applicable to reduce risk during scale‐up of filtration processes and should be suitable for feed‐forward and feed‐back process control. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 32:108–115, 2016     

Differences in the diversity and composition of the pollinator assemblage of two co-flowering congeneric alpine wallflowers, Erysimum nevadense and E. baeticum

Many alpine plants display a generalist pollination system where almost any available flower visitor could act as a legitimate pollinator. Co-flowering related plant species displaying a generalized pollination system can decrease their fitness due to interspecific mating. In this study, we determine the difference in diversity and composition of the pollination systems of two co-occurring species endemic to the alpine region of the Sierra Nevada (SE Spain), Erysimum nevadense Reut. and Erysimum baeticum baeticum (Heywood) Polatschek (Brassicaceae), and check for the potential role of floral and plant traits in explaining the observed differences. For this, we labeled 30 plants in two populations of each plant species located in the same area. We determined flower visitor assemblage by sampling all insects approaching the flowers and contacting the sexual organs during 60-min surveys. We found that the diversity of the pollinator assemblage was similar between the two studied wallflower species, both species showing a much generalized pollination system. However, the composition of the pollinator assemblage was different, since the flowers of E. nevadense were visited mostly by beetles and in a lesser extent by hover-flies, whereas the flowers of E. baeticum baeticum were visited mostly by ants and bees. Interestingly, flower traits varied between species, with E. nevadense displaying yellow, smaller and shallower flowers and E. baeticum baeticum displaying purple, large and deeper flowers. These findings suggest that differences in floral traits can explain the observed differences in the composition of the pollinator assemblage between both wallflower species.     

Oxidative stress induced in tobacco leaves by chloroplast over-expression of maize plastidial transglutaminase

As part of a project aiming to characterize the role of maize plastidial transglutaminase (chlTGZ) in the plant chloroplast, this paper presents results on stress induced by continuous chlTGZ over-expression in transplastomic tobacco leaves. Thylakoid remodelling induced by chlTGZ over-expression in young leaves of tobacco chloroplasts has already been reported (Ioannidis et al. in Biochem Biophys Acta 1787:1215–1222, 2009). In the present work, we determined the induced alterations in the photosynthetic apparatus, in the chloroplast ultrastructure, and, particularly, the activation of oxidative and antioxidative metabolism pathways, regarding ageing and functionality of the tobacco transformed plants. The results revealed that photochemistry impairment and oxidative stress increased with transplastomic leaf age. The decrease in pigment levels in the transformed leaves was accompanied by an increase in H₂O₂ and lipid peroxidation. The rise in H₂O₂ correlated with a decrease in catalase activity, whereas there was an increase in peroxidase activity. In addition, chlTGZ over-expression lead to a drop in reduced glutathione, while Fe-superoxide dismutase activity was higher in transformed than in wild-type leaves. Together with the induced oxidative stress, the over-expressed chlTGZ protein accumulated progressively in chloroplast inclusion bodies. These traits were accompanied by thylakoid scattering, membrane degradation and reduction of thylakoid interconnections. Consequently, the electron transport between photosystems decrease in the old leaves. In spite of these alterations, transplastomic plants can be maintained and reproduced in vitro. These results are discussed in line with chlTGZ involvement in chloroplast functionality.