Foraging habitats and floral resource use by colonies of long- and short-tongued bumble bee species in an agricultural landscape with kabocha squash fields

Bumble bees pollinate and forage on flowers of crop and wild plants in agricultural landscapes. These interactions may depend on landscape patterns and bumble bee traits. We studied the abundance, colony density, and foraging range in long-tongued Bombus diversus Smith and short-tongued B. hypocrita Pérez, and evaluated their visits to flowers of wild plants and cultivated kabocha squash (Cucurbita maxima Duchesne). In forests in a farmland, B. hypocrita workers were trapped more frequently in the canopy. Full-sibs determined by nuclear microsatellite genotypes among workers collected in the farmland showed higher colony density and a larger foraging radius in B. hypocrita (30.8 km^?2 and 848 m) than in B. diversus (8.3 km^?2 and 723 m), respectively. Regarding wild plants, workers more frequently visited shallow flowers in B. hypocrita and deep flowers in B. diversus. These results suggest that bumble bees with different traits forage on different wild flowers in different habitats. Squash flowers were visited by both bumble bee species at similar frequency in the latter period of colony growth when males and new queens appeared. Composition of full-sib workers visiting squash and wild flowers did not depend on the number of collected workers of individual colonies, indicating that foraging on squash flowers was not associated with colony growth. Thus, growth and reproduction of bumble bee colonies may be supported by various wild plants and cultivated squash, respectively.     

Identification and Characterization of d-Hydroxyproline Dehydrogenase and Δ1-Pyrroline-4-hydroxy-2-carboxylate Deaminase Involved in Novel l-Hydroxyproline Metabolism of Bacteria: METABOLIC CONVERGENT EVOLUTION*

l-Hydroxyproline (4-hydroxyproline) mainly exists in collagen, and most bacteria cannot metabolize this hydroxyamino acid. Pseudomonas putida and Pseudomonas aeruginosa convert l-hydroxyproline to α-ketoglutarate via four hypothetical enzymatic steps different from known mammalian pathways, but the molecular background is rather unclear. Here, we identified and characterized for the first time two novel enzymes, d-hydroxyproline dehydrogenase and Δ¹-pyrroline-4-hydroxy-2-carboxylate (Pyr4H2C) deaminase, involved in this hypothetical pathway. These genes were clustered together with genes encoding other catalytic enzymes on the bacterial genomes. d-Hydroxyproline dehydrogenases from P. putida and P. aeruginosa were completely different from known bacterial proline dehydrogenases and showed similar high specificity for substrate (d-hydroxyproline) and some artificial electron acceptor(s). On the other hand, the former is a homomeric enzyme only containing FAD as a prosthetic group, whereas the latter is a novel heterododecameric structure consisting of three different subunits (α₄β₄γ₄), and two FADs, FMN, and [2Fe-2S] iron-sulfur cluster were contained in αβγ of the heterotrimeric unit. These results suggested that the l-hydroxyproline pathway clearly evolved convergently in P. putida and P. aeruginosa. Pyr4H2C deaminase is a unique member of the dihydrodipicolinate synthase/N-acetylneuraminate lyase protein family, and its activity was competitively inhibited by pyruvate, a common substrate for other dihydrodipicolinate synthase/N-acetylneuraminate lyase proteins. Furthermore, disruption of Pyr4H2C deaminase genes led to loss of growth on l-hydroxyproline (as well as d-hydroxyproline) but not l- and d-proline, indicating that this pathway is related only to l-hydroxyproline degradation, which is not linked to proline metabolism.     

The juvenile myoclonic epilepsy-related protein EFHC1 interacts with the redox-sensitive TRPM2 channel linked to cell death

The transient receptor potential M2 channel (TRPM2) is the Ca(2+)-permeable cation channel controlled by cellular redox status via β-NAD(+) and ADP-ribose (ADPR). TRPM2 activity has been reported to underlie susceptibility to cell death and biological processes such as inflammatory cell migration and insulin secretion. However, little is known about the intracellular mechanisms that regulate oxidative stress-induced cell death via TRPM2. We report here a molecular and functional interaction between the TRPM2 channel and EF-hand motif-containing protein EFHC1, whose mutation causes juvenile myoclonic epilepsy (JME) via mechanisms including neuronal apoptosis. In situ hybridization analysis demonstrates TRPM2 and EFHC1 are coexpressed in hippocampal neurons and ventricle cells, while immunoprecipitation analysis demonstrates physical interaction of the N- and C-terminal cytoplasmic regions of TRPM2 with the EFHC1 protein. Coexpression of EFHC1 significantly potentiates hydrogen peroxide (H(2)O(2))- and ADPR-induced Ca(2+) responses and cationic currents via recombinant TRPM2 in HEK293 cells. Furthermore, EFHC1 enhances TRPM2-conferred susceptibility of HEK293 cells to H(2)O(2)-induced cell death, which is reversed by JME mutations. These results reveal a positive regulatory action of EFHC1 on TRPM2 activity, suggesting that TRPM2 contributes to the expression of JME phenotypes by mediating disruptive effects of JME mutations of EFHC1 on biological processes including cell death.     

Influence of the intensity of a conditioning contraction on the subsequent twitch torque and maximal voluntary concentric torque

This study aimed to clarify the influence of the intensity of a conditioning contraction on subsequent isometric twitch and maximal voluntary concentric torques. Subjects (n=12men) performed voluntary isometric plantar flexion for six seconds as a conditioning contraction, at intensities of 40%, 60%, 80% and 100% of a maximal voluntary isometric contraction (MVIC). Before and immediately after the conditioning contraction, isometric twitch and maximal voluntary concentric (180°/s) plantar flexion torques were determined. Surface electromyograms were recorded from the triceps surae muscles and M-wave amplitudes and root-mean-square values of the electromyographic signals (RMS(EMG)) were calculated. The isometric twitch torque increased significantly after conditioning contraction at all intensities (P<0.05), whereas maximal voluntary concentric torque increased significantly only at 80% and 100% MVIC conditions (P<0.05). It is concluded that during a six second conditioning contraction, the effect of the intensity of a conditioning contraction on subsequent torque development is different between an isometric twitch and maximal voluntary concentric contractions, with the latter being less affected.     

Tumefactive multiple sclerosis requiring emergent biopsy and histological investigation to confirm the diagnosis: a case report

Introduction

Tumefactive multiple sclerosis is a demyelinating disease that demonstrates tumor-like features on magnetic resonance imaging. Although diagnostic challenges without biopsy have been tried by employing radiological studies and cerebrospinal fluid examinations, histological investigation is still necessary for certain diagnosis in some complicated cases.

Case presentation

A 37-year-old Asian man complaining of mild left leg motor weakness visited our clinic. Magnetic resonance imaging demonstrated high-signal lesions in bilateral occipital forceps majors, the left caudate head, and the left semicentral ovale on fluid-attenuated inversion recovery and T2-weighted imaging, and these lesions were enhanced by gadolinium-dimeglumin. Tumefactive multiple sclerosis was suspected because the enhancement indistinctly extended along the corpus callosum on magnetic resonance imaging and scintigraphy showed a low malignancy of the lesions. But oligoclonal bands were not detected in cerebrospinal fluid. In a few days, his symptoms fulminantly deteriorated with mental confusion and left hemiparesis, and steroid pulse therapy was performed. In spite of the treatment, follow-up magnetic resonance imaging showed enlargement of the lesions. Therefore, emergent biopsy was performed and finally led to the diagnosis of demyelinating disease. The enhanced lesion on magnetic resonance imaging disappeared after one month of prednisolone treatment, but mild disorientation and left hemiparesis remained as sequelae.

Conclusions

Fulminant aggravation of the disease can cause irreversible neurological deficits. Thus, an early decision to perform a biopsy is necessary for exact diagnosis and appropriate treatment if radiological studies and cerebrospinal fluid examinations cannot rule out the possibility of brain tumors.     

Clinical proteomics identified ATP-dependent RNA helicase DDX39 as a novel biomarker to predict poor prognosis of patients with gastrointestinal stromal tumor

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal malignancy of the gastrointestinal tract, comprising a wide spectrum from a curable disorder to highly malignant disease. GIST is characterized by tyrosine kinase mutations, and molecular targeting therapies against these abnormal enzymes require prognostic biomarkers. To identify candidate prognostic biomarkers, we examined proteomic features corresponding to metastasis after surgery. Using two-dimensional difference gel electrophoresis with a large format gel, we compared the primary tumor tissues of GIST patients free of metastasis for two years after surgery (eight cases) with those of patients who developed metastasis within one year after surgery (nine cases). We found the intensities of 38 protein spots to differ significantly between the two groups. Mass spectrometric protein identification revealed that these corresponded to 25 unique genes. Immunohistochemical validation demonstrated ATP-dependent RNA helicase DDX39 to be significantly associated with metastasis and poor clinical outcomes in a group of 72 GIST patients. In conclusion, we have established a novel prognostic utility of ATP-dependent RNA helicase DDX39 in GIST.ATP-dependent RNA helicase DDX39, a novel biomarker for GIST likely to be associated with metastatic disease, can identify patients likely to benefit from new therapeutic strategies such as tyrosine kinase inhibitors.     

S-LOCUS EARLY FLOWERING 3 is exclusively present in the genomes of short-styled buckwheat plants that exhibit heteromorphic self-incompatibility

The different forms of flowers in a species have attracted the attention of many evolutionary biologists, including Charles Darwin. In Fagopyrum esculentum (common buckwheat), the occurrence of dimorphic flowers, namely short-styled and long-styled flowers, is associated with a type of self-incompatibility (SI) called heteromorphic SI. The floral morphology and intra-morph incompatibility are both determined by a single genetic locus named the S-locus. Plants with short-styled flowers are heterozygous (S/s) and plants with long-styled flowers are homozygous recessive (s/s) at the S-locus. Despite recent progress in our understanding of the molecular basis of flower development and plant SI systems, the molecular mechanisms underlying heteromorphic SI remain unresolved. By examining differentially expressed genes from the styles of the two floral morphs, we identified a gene that is expressed only in short-styled plants. The novel gene identified was completely linked to the S-locus in a linkage analysis of 1,373 plants and had homology to EARLY FLOWERING 3. We named this gene S-LOCUS EARLY FLOWERING 3 (S-ELF3). In an ion-beam-induced mutant that harbored a deletion in the genomic region spanning S-ELF3, a phenotype shift from short-styled flowers to long-styled flowers was observed. Furthermore, S-ELF3 was present in the genome of short-styled plants and absent from that of long-styled plants both in world-wide landraces of buckwheat and in two distantly related Fagopyrum species that exhibit heteromorphic SI. Moreover, independent disruptions of S-ELF3 were detected in a recently emerged self-compatible Fagopyrum species and a self-compatible line of buckwheat. The nonessential role of S-ELF3 in the survival of individuals and the prolonged evolutionary presence only in the genomes of short-styled plants exhibiting heteromorphic SI suggests that S-ELF3 is a suitable candidate gene for the control of the short-styled phenotype of buckwheat plants.     

Facile synthesis of stable lipid analogues possessing a range of alkyl groups: application to artificial glycolipids

Efficient preparation of lipid analogues is described in which various long alkoxy chains and 2-hydroxyethyl group were covalently linked with benzoic acid derivatives. An -mannopyranosyl group was stereoselectively introduced by the conventional imidate method into the terminal hydroxy group without any alternation of other moieties in a molecule. The resulting new glycoconjugates acted as models of natural glycolipids for protein-carbohydrate interactions.     

Hypothermic preservation effect on mammalian cells of type III antifreeze proteins from notched-fin eelpout

Antifreeze proteins (AFPs) can bind to the surface of ice crystals and have also been suggested to protect cells from hypothermic damage. The present study reports that type III AFPs from notched-fin eelpout, Zoarces elongatus Kner, can protect cells during hypothermic storage. This fish naturally expresses at least 13 isoforms of type III AFP (denoted NfeAFPs), the primary sequences of which were categorized into SP- and QAE-Sephadex binding groups (SP- and QAE-isoforms). We compared the preservation ability between the extracted isoform mixtures (NfeAFPs) and a recombinant single SP-isoform (RcNfeAFP6). Experiments were performed using cultivated mammalian cells (HepG2) exposed to 4 °C for 24–72 h. The preserved cells were evaluated by measuring LDH released, intracellular ATP, and WST-8 reduction. It appeared that the protective effect of the 2 samples increases dose-dependently at concentrations between 2 and 10 mg/ml. Under highest soluble amount of the protein (10 mg/ml), cell viability significantly improved compared with the ordinary preservation fluid (P < 0.01). This effect was larger with NfeAFPs than with RcNfeAFP6 at the same concentration. The successful hypothermic preservation of cells using natural NfeAFPs may have a wide range of applications for cell engineering and clinical medical care.     

Cryptic fragment alpha4 LG4-5 derived from laminin alpha4 chain inhibits de novo adipogenesis by modulating the effect of fibroblast growth factor-2

Cleavage of the extracellular matrix (ECM) by proteolysis unmasks cryptic sites and generates novel fragments with biological activities functionally distinct from those of the intact ECM molecule. The laminin G-like (LG)4-5 fragment has been shown to be excised from the laminin α 4 chain in various tissues. However, the functional role of this fragment has remained unknown to date. To investigate this, we prepared α 4 LG1-3 and α 4 LG4-5 fragments by elastase digestion of recombinant α 4 LG1-5, and examined their effects on de novo adipogenesis in mice at the site of injection of basement membrane extract (Matrigel) and fibroblast growth factor (FGF)-2. Although the addition of whole α 4 LG1-5 suppressed adipogenesis to some extent, the α 4 LG4-5 fragment could strongly suppress adipogenesis at a concentration of less than 20 n m . Addition of the α 4 LG4 module, which contains a heparin-binding region, had a suppressive effect, but this was lost in mutants with reduced heparin-binding activity. In addition, antibodies against the extracellular domain of syndecan-2 and -4, which are known receptors for the α 4 LG4 module, suppressed adipogenesis. Thus, these results suggest that the cryptic α 4 LG4-5 fragment derived from the laminin α 4 chain inhibits de novo adipogenesis by modulating the effect of FGF-2 through syndecans.