Fallacies and false premises—a critical assessment of the arguments for the recognition of paraphyletic taxa in botany

One of the central controversies in contemporary taxonomy and systematics revolves around whether to accept or to reject paraphyletic taxa. The present review is the result of a survey of the ongoing discussion in botany over the past ca. 15 years, and attempts to systematically and critically assess all individual arguments presented for the formal recognition of paraphyletic groups in the classification of life. Where arguments are found to be without merit, rebuttals are presented in the hope of excluding them from further discussion, which can then concentrate on those that have merit. Where arguments are found to be sound, their implications and possible solutions are discussed. The controversy around paraphyletic taxa can be broken down into three questions: whether their rejection or acceptance would lead to a classification better reflecting patterns of biological diversity and evolutionary history; whether their rejection or acceptance would lead to a more practical, useful and predictive classification; and whether their rejection is compatible with ranked and binary Linnaean taxonomy. All available arguments for paraphyletic taxa relating to the first question are demonstrated to be based on various logical fallacies or false premises, especially misunderstandings of the principles of phylogenetic systematics. The issue of usefulness is harder to resolve, as different classifications serve different needs. It is presumably unavoidable but also preferable that phylogenetic and non‐phylogenetic ways of classifying species continue to coexist, serving different needs. Finally, an insistence on monophyletic taxa is found to be incompatible with binary taxonomy under a set of very specific circumstances and assumptions whose presence and accuracy are not universally accepted. © The Willi Hennig Society 2011.     

Autophagy as the cell survival in response to a microsporidian infection of the midgut epithelium of Isohypsibius granulifer granulifer (Eutardigrada: Hypsibiidae)

The midgut epithelial cells of many invertebrates may possess microorganisms which act as symbionts or pathogens (bacteria, microsporidia, viruses). During our previous studies on Isohypsibius granulifer granulifer Thulin, 1928 (Tardigrada, Eutardigrada), which examined alterations of the midgut epithelium during oogenesis, we found that some of the specimens were infected with microsporidia. All stages of pathogens occurred in the cytoplasm of the digestive cells in the midgut epithelium of I. g. granulifer that were infected with microsporidia: meronts, sporonts, sporoblasts, and spores. The cytoplasm of the digestive cells was rich in mitochondria, cisterns of rough endoplasmic reticulum (RER), and Golgi complexes. Autophagy in the digestive cells of the dorsal midgut was much more intensive in comparison with noninfected specimens. Membranes of phagophores surrounded the pathogens forming autophagosomes. These latter structures fused with lysosomes forming autolysosomes and residual bodies appeared. Neither glycogen granules nor droplets of varying electron density, which accumulated in digestive cells during vitellogenesis and choriogenesis, appeared in individuals with microsporidia. While the midgut epithelium in noninfected specimens takes part in vitellogenesis and choriogenesis, in infected specimens, midgut cells are involved in the process of autophagy as a survival strategy.     

Sensitive and High Resolution Localization and Tracking of Membrane Proteins in Live Cells with BRET

Peripheral and integral membrane proteins can be located in several different subcellular compartments, and it is often necessary to determine the location of such proteins or to track their movement in living cells. Image‐based colocalization of labeled membrane proteins and compartment markers is frequently used for this purpose, but this method is limited in terms of throughput and resolution. Here we show that bioluminescence resonance energy transfer (BRET) between membrane proteins of interest and compartment‐targeted BRET partners can report subcellular location and movement of membrane proteins in live cells. The sensitivity of the method is sufficient to localize a few hundred protein copies per cell. The spatial resolution can be sufficient to determine membrane topology, and the temporal resolution is sufficient to track changes that occur in less than 1 second. BRET requires little user intervention, and is thus amenable to large‐scale experimental designs with standard instruments.     

Surface Chirality of Gly‐Pro Dipeptide Adsorbed on a Cu(110) Surface

The adsorption of chiral Gly‐Pro dipeptide on Cu(110) has been characterized by combining in situ polarization modulation infrared reflection absorption spectroscopy (PM‐RAIRS) and X‐ray photoelectron spectroscopy (XPS). The chemical state of the dipeptide, and its anchoring points and adsorption geometry, were determined at various coverage values. Gly‐Pro molecules are present on Cu(110) in their anionic form (NH₂/COO⁻) and adsorb under a 3‐point binding via both oxygen atoms of the carboxylate group and via the nitrogen atom of the amine group. Low‐energy electron diffraction (LEED) and scanning tunneling microscopy (STM) have shown the presence of an extended 2D chiral array, sustained via intermolecular H‐bonds interactions. Furthermore, due to the particular shape of the molecule, only one homochiral domain is formed, creating thus a truly chiral surface. Chirality 27:411–416, 2015. © 2015 Wiley Periodicals, Inc.     

Hyperosmolarity enhanced susceptibility to renal tubular fibrosis by modulating catabolism of type I transforming growth factor‐β receptors

Hyperosmolarity plays an essential role in the pathogenesis of diabetic tubular fibrosis. However, the mechanism of the involvement of hyperosmolarity remains unclear. In this study, mannitol was used to evaluate the effects of hyperosmolarity on a renal distal tubule cell line (MDCK). We investigated transforming growth factor‐β receptors and their downstream fibrogenic signal proteins. We show that hyperosmolarity significantly enhances the susceptibility to exogenous transforming growth factor (TGF)‐β1, as mannitol (27.5 mM) significantly enhanced the TGF‐β1‐induced increase in fibronectin levels compared with control experiments (5.5 mM). Specifically, hyperosmolarity induced tyrosine phosphorylation on TGF‐β RII at 336 residues in a time (0–24 h) and dose (5.5–38.5 mM) dependent manner. In addition, hyperosmolarity increased the level of TGF‐β RI in a dose‐ and time‐course dependent manner. These observations may be closely related to decreased catabolism of TGF‐β RI. Hyperosmolarity significantly downregulated the expression of an inhibitory Smad (Smad7), decreased the level of Smurf 1, and reduced ubiquitination of TGF‐β RI. In addition, through the use of cycloheximide and the proteasome inhibitor MG132, we showed that hyperosmolarity significantly increased the half‐life and inhibited the protein level of TGF‐β RI by polyubiquitination and proteasomal degradation. Taken together, our data suggest that hyperosmolarity enhances cellular susceptibility to renal tubular fibrosis by activating the Smad7 pathway and increasing the stability of type I TGF‐β receptors by retarding proteasomal degradation of TGF‐β RI. This study clarifies the mechanism underlying hyperosmotic‐induced renal fibrosis in renal distal tubule cells. J. Cell. Biochem. 109: 663–671, 2010. © 2010 Wiley‐Liss, Inc.     

A modified cornish pasty method for ex ovo culture of the chick embryo development

Chick embryos grown in ex ovo culture by the modified Cornish pasty method reported in Nagai, Lin and Sheng in this issue.