Carbohydrate composition of the isolated cell walls of dermatophytes

In an attempt to evaluate taxonomic character of sugar composition of dermatophytes, the purified cell walls from 13 species are analyzed on neutral sugar composition by gas liquid chromatography. The results were principally compatible with those obtained by conventional morphological examination. Neutral sugar components of dermatophytes cell walls were mannose and glucose in the ratio of 1∶2.7 for Epidermophyton and 1∶1.4 for Microsporum. There were two types in Trichophyton, in which the ratios of mannose to glucose were 1∶1.6 and 1∶3.8. The cases of Trichophyton ferrugineum and Trichophyton mentagrophytes were exceptional. The ratio of the former was 1∶1.4, which implied the relation to Microsporum group, and the ratio of the latter was 1∶2.3, which was supposed to be the intermediate of two types of Trichophyton group. Albino type cell wall of Epidermophyton floccosum was more rich in glucose than pigmented type one.     

Stochastic combinations of actin regulatory proteins are sufficient to drive filopodia formation

Assemblies of actin and its regulators underlie the dynamic morphology of all eukaryotic cells. To understand how actin regulatory proteins work together to generate actin-rich structures such as filopodia, we analyzed the localization of diverse actin regulators within filopodia in Drosophila embryos and in a complementary in vitro system of filopodia-like structures (FLSs). We found that the composition of the regulatory protein complex where actin is incorporated (the filopodial tip complex) is remarkably heterogeneous both in vivo and in vitro. Our data reveal that different pairs of proteins correlate with each other and with actin bundle length, suggesting the presence of functional subcomplexes. This is consistent with a theoretical framework where three or more redundant subcomplexes join the tip complex stochastically, with any two being sufficient to drive filopodia formation. We provide an explanation for the observed heterogeneity and suggest that a mechanism based on multiple components allows stereotypical filopodial dynamics to arise from diverse upstream signaling pathways.     

Structure Analysis of Proteins and Peptides by Difference Circular Dichroism Spectroscopy

The Protein Journal - Difference circular dichroism (CD) spectroscopy was used here to characterize changes in structure of flexible peptides upon altering their environments. Environmental changes...     

Cooperation of the IFT-A complex with the IFT-B complex is required for ciliary retrograde protein trafficking and GPCR import

Cilia sense and transduce extracellular signals via specific receptors. The intraflagellar transport (IFT) machinery mediates not only bidirectional protein trafficking within cilia but also the import/export of ciliary proteins across the ciliary gate. The IFT machinery is known to comprise two multisubunit complexes, namely, IFT-A and IFT-B; however, little is known about how the two complexes cooperate to mediate ciliary protein trafficking. We here show that IFT144–IFT122 from IFT-A and IFT88–IFT52 from IFT-B make major contributions to the interface between the two complexes. Exogenous expression of the IFT88(Δα) mutant, which has decreased binding to IFT-A, partially restores the ciliogenesis defect of IFT88-knockout (KO) cells. However, IFT88(Δα)-expressing IFT88-KO cells demonstrate a defect in IFT-A entry into cilia, aberrant accumulation of IFT-B proteins at the bulged ciliary tips, and impaired import of ciliary G protein–coupled receptors (GPCRs). Furthermore, overaccumulated IFT proteins at the bulged tips appeared to be released as extracellular vesicles. These phenotypes of IFT88(Δα)-expressing IFT88-KO cells resembled those of IFT144-KO cells. These observations together indicate that the IFT-A complex cooperates with the IFT-B complex to mediate the ciliary entry of GPCRs as well as retrograde trafficking of the IFT machinery from the ciliary tip.     

Microwave irradiation for fixation and immunostaining of endothelial cells in situ

Using microwave irradiation during tissue fixation and immunostaining reduces sample preparation time and facilitates penetration of fixatives and antibody solutions into the tissues. This results in improved fixation and reduction of non-specific binding of antibodies, respectively. Experimental analyses of endothelial cells in blood vessels in situ have been limited because of the difficulty of tissue preparation. We report here a technique using intermittent microwave irradiation for blood vessel fixation and immunostaining the fixed tissues. Intermittent microwave irradiation during fixation reduced blood vessel contraction and resulted in well preserved morphology of blood vessels, especially the endothelial cells. Microwave irradiation also reduced non-specific binding of fluorescein-labeled antibodies. These microwave irradiation-assisted techniques are useful for analysis of endothelial cell function and for pathological study of blood vessels in situ.     

Reaction of 2-Deoxy-2-C-(3-bromoacetoxypropyl)-α-D-arabinofuranosides with Oligonucleotide1

Abstract

Reaction of methyl 2-deoxy-2-C-(3-bromoacetoxypropyl)-α-D-arabinofuranosides, prepared from methyl 2,3-anhydro-α-D-ribofuranoside, with oligodeoxyribonucleotide (21mer) in acetonitrile-H₂O (pH 7) and subsequent treatment with piperidine resulted in the cleavage of the nucleotide chain at the position G, A, and C.     

Tailoring the Peptide-Binding Specificity Of An RNA by Combinations of Specificity-Altering Mutations

In this study, the ability to tailor the peptide-binding specificity of an RNA was investigated. First, variants of the Rev-response element (RRE) RNA with different specificities toward the natural binding partner, Rev, and two RRE-binding aptamers, the RSG-1.2 and the Kl peptides, were identified. Next, hybrid RRE mutants with combinations of two sets of specificity-altering substitutions were tested for peptide-binding specificity. It was shown that in most cases the results of the combination of individual mutations were of an additive nature, therefore providing a way to manipulate the peptide-binding specificity of an RNA in a predictable manner.     

Synthesis of Methylenecyclobutyl- and Cyclobutenyl Adenine,Potent Antiviral Carbocyclic Analogues of Oxetanocin A

Abstract

9-Cyclobutyladenines bearing both methylene and hydroxymethyl groups, 3 and 4, were prepared by dehydration of carbocyclic oxetanocin A (1a). Introduction of a double bond into cyclobutane ring was achieved by allylic oxidation of N ⁶-benzoyl-9-[3-methylenecyclobutyl]adenine (12), which after several steps, afforded 9-[3-(hydroxy-methyl)-2-cyclobutenyl)adenine (5).     

Profile of micronucleus frequencies and nuclear abnormalities in different species of electric fishes (Gymnotiformes) from the Eastern Amazon

The frequency of spontaneous micronucleus (MN) formation in fish species needs to be determined to evaluate their usefulness for genotoxic biomonitoring. The definition of a good bioindicator takes into account the current knowledge of its metabolic traits as well as other factors including its feeding behavior and relationship to the environment. In this study, we compared the basal frequencies of micronucleated erythrocytes and nuclear abnormalities (NA) among different species of the fish Order Gymnotiformes (Rhamphichthys marmoratus, Steatogenys elegans, Sternopygus macrurus, Parapteronotus hasemani, Gymnotus mamiraua, Gymnotus arapaima, Brachyhypopomus beebei, Brachyhypopomus n. sp. BENN) sampled in several localities of the Eastern Amazon. A baseline of MN and NA frequency in these fish was determined, enabling the identification of potentially useful species as models for genotoxicity studies. Only one impacted sample collected at a site in the River Caripetuba showed a significant number of NAs, which may be due to the release of wastewater by neighbouring mining industries and by the burnt fuel released by the small boats used by a local community. Our results may provide support for further studies in areas of the Eastern Amazon affected by mining, deforestation and other anthropogenic activities.     

Growth-Dependent Catalase Localization in Exiguobacterium oxidotolerans T-2-2T Reflected by Catalase Activity of Cells

A psychrotolerant and H₂O₂-resistant bacterium, Exiguobacterium oxidotolerans T-2-2^T, exhibits extraordinary H₂O₂ resistance and produces catalase not only intracellularly but also extracellularly. The intracellular and extracellular catalases exhibited the same enzymatic characteristics, that is, they exhibited the temperature-dependent activity characteristic of a cold-adapted enzyme, their heat stabilities were similar to those of mesophilic enzymes and very high catalytic intensity. In addition, catalase gene analysis indicated that the bacterium possessed the sole clade 1 catalase gene corresponding to intracellular catalase. Hence, intracellular catalase is secreted into the extracellular space. In addition to intracellular and extracellular catalases, the inner circumference of the cells showed the localization of catalase in the mid-stationary growth phase, which was observed by immunoelectron microscopy using an antibody against the intracellular catalase of the strain. The cells demonstrated higher catalase activity in the mid-stationary growth phase than in the exponential growth phase. The catalase localized in the inner circumference can be dissociated by treatment with Tween 60. Thus, the localized catalase is not tightly bound to the inner circumference of the cells and may play a role in the oxidative defense of the cells under low metabolic state.