Effect of iTRAQ Labeling on the Relative Abundance of Peptide Fragment Ions Produced by MALDI-MS/MS

The identification of proteins in proteomics experiments is usually based on mass information derived from tandem mass spectrometry data. To improve the performance of the identification algorithms, additional information available in the fragment peak intensity patterns has been shown to be useful. In this study, we consider the effect of iTRAQ labeling on the fragment peak intensity patterns of singly charged peptides from MALDI tandem MS data. The presence of an iTRAQ-modified basic group on the N-terminus leads to a more pronounced set of b-ion peaks and distinct changes in the abundance of specific peptide types. We performed a simple intensity prediction by using a decision-tree machine learning approach and were able to show that the relative ion abundance in a spectrum can be correctly predicted and distinguished from closely related sequences. This information will be useful for the development of improved method-specific intensity-based protein identification algorithms.     

Seta ultrastructure in Pogonatum aloides Hedw

Abstract

The seta ultrastructure in Pogonatum aloides Hedw. has been observed by electron microscopy. We have observed the conductive cells in the sporophyte of Pogonatum aloides by the transversal and the longitudinal sections moreover in transections, the cells of the parenchymatic ring have more developed plastids than the cells of the cortex. The similarities and differences in the disposition of the conductive cells within the same or in different subclasses is discussed.     

N-terminal domain antigenic mapping reveals a site of vulnerability for SARS-CoV-2

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Developmental stages and gut microenvironments influence gut microbiota dynamics in the invasive beetle Popillia japonica Newman (Coleoptera: Scarabaeidae)

Popillia japonica Newman (Coleoptera: Scarabaeidae) is a highly polyphagous invasive beetle originating from Japan. This insect is highly resilient and able to rapidly adapt to new vegetation. Insect-associated microorganisms can play important roles in insect physiology, helping their hosts to adapt to changing conditions and potentially contributing to an insect's invasive potential. Such symbiotic bacteria can be part of a core microbiota that is stably transmitted throughout the host's life cycle or selectively recruited from the environment at each developmental stage. The aim of this study was to investigate the origin, stability and turnover of the bacterial communities associated with an invasive population of P. japonica from Italy. Our results demonstrate that soil microbes represent an important source of gut bacteria for P. japonica larvae, but as the insect develops, its gut microbiota richness and diversity decreased substantially, paralleled by changes in community composition. Notably, only 16.75% of the soil bacteria present in larvae are maintained until the adult stage. We further identified the micro-environments of different gut sections as an important factor shaping microbiota composition in this species, likely due to differences in pH, oxygen availability and redox potential. In addition, P. japonica also harboured a stable bacterial community across all developmental stages, consisting of taxa well known for the degradation of plant material, namely the families Ruminococcacae, Christensenellaceae and Lachnospiraceae. Interestingly, the family Christensenallaceae had so far been observed exclusively in humans. However, the Christensenellaceae operational taxonomic units found in P. japonica belong to different taxonomic clades within this family.     

Characterization of a monoclonal antibody directed against the epidermal growth factor receptor binding site

Summary In this work a new monoclonal antibody (mAb), designated MGR1, which recognizes the epidermal growth factor receptor (EGF-R) binding site, is described. The main characteristic of this mAb is its ability to discriminate between cells that express normal levels of EGF-R from cells with overexpression, the detectability threshold by immunocytochemical tests being 5 × 10⁴ receptors/cell of 10 µm diameter. MGR1 was found to inhibit EGF binding on the relevant target cells, and vice versa its binding was inhibited by EGF, which indicated that MGR1 recognizes the EGF receptor binding site. MGR1 exerted an inhibitory effect on both the in vitro and in vivo growth of cells with EGF-R overexpression, but had no effect on cells with a normal expression of the receptor. Tumour growth inhibition in athymic mice was also obtained on already implanted tumours. MGR1 therefore seems to be an adequate reagent for the development of immunotherapeutical approaches suitable for the treatment of tumours with EGF-R overexpression.     

Progesterone binding in rabbit oviduct and uterus.

Progesterone binding of high affinity with a dissociation constant of 10(-9) M was identified in cytosol of rabbit oviduct and uterus. Macromolecules with sedimentation coefficients of 7-8 S and 4-5 S were present. Progesterone receptor concentration was two to fivefold lower in the oviduct when compared with the uterus. The receptor concentration declined steadily from 3 hr until 144 hr after mating in the uterus; however, the decline in oviductal receptor was not significant until the sixth day of pregnancy. Progesterone receptor concentration in rabbit oviduct and uterus in estrus and early pregnancy was greater than estradiol receptor levels.     

A p300 and SIRT1 Regulated Acetylation Switch of C/EBPα Controls Mitochondrial Function

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Effect of the leader sequence on the expression of recombinant C. rugosa lipase by S. cerevisiae cells

Summary The Candida rugosa lipase I gene has been expressed in Saccharomyces cerevisiae. The recombinant lipase was efficiently synthesized only following the replacement of the enzyme endogenous leader sequence with the signal peptide of the Kluyveromyces lactis killer toxin. Amount of accumulated lipase was about 10–20 mg/l in batch culture and over 1g/l in a computer-controlled fed-batch fermentation system.