Characteristics of usurped colonies in the subtropical paper wasp,Ropalidia fasciata (Hymenoptera: Vespidae)

Summary Nest usurpation in the subtropical paper waspRopalidia fasciata was studied in Okinawa, southern Japan. Eight of 14 usurpations occurred around the first worker emergence (within 3 days before and 3 days after the emergence). A discriminant analysis showed that the usurpers preferred colonies that had fewer adult females and fewer cells but abundant pupae, compared with non-usurped colonies in the study area on same dates. This suggests that usurpers can assess the development of other colonies and then select a nest that is easy to usurp (fewer females) but has valuable resources (abundant pupae).     

Changes of aliphatic C–H bonds in cyanobacteria during experimental thermal maturation in the presence or absence of silica as evaluated by FTIR microspectroscopy

Aliphatic C–H bonds are one of the major organic signatures detected in Proterozoic organic microfossils, and their origin is a topic of interest. To investigate the influence of the presence of silica on the thermal alteration of aliphatic C–H bonds in prokaryotic cells during diagenesis, cyanobacteria Synechocystis sp. PCC6803 were heated at temperatures of 250–450°C. Changes in the infrared (IR) signals were monitored by micro‐Fourier transform infrared (FTIR) spectroscopy. Micro‐FTIR shows that absorbances at 2,925 cm^?1 band (aliphatic CH₂) and 2,960 cm^?1 band (aliphatic CH₃) decrease during heating, indicating loss of the C–H bonds, which was delayed by the presence of silica. A theoretical approach using solid‐state kinetics indicates that the most probable process for the aliphatic C–H decrease is three‐dimensional diffusion of alteration products under both non‐embedded and silica‐embedded conditions. The extrapolation of the experimental results obtained at 250–450°C to lower temperatures implies that the rate constant for CH₃ (k_CH3) is similar to or lower than that for CH₂ (k_CH2; i.e., CH₃ decreases at a similar rate or more slowly than CH₂). The peak height ratio of 2,960 cm^?1 band (CH₃)/2,925 cm^?1 band (CH₂; R_3/2 values) either increased or remained constant during the heating. These results reveal that the presence of silica does affect the decreasing rate of the aliphatic C–H bonds in cyanobacteria during thermal maturation, but that it does not significantly decrease the R_3/2 values. Meanwhile, studies of microfossils suggest that the R_3/2 values of Proterozoic prokaryotic fossils from the Bitter Springs Group and Gunflint Formation have decreased during fossilization, which is inconsistent with the prediction from our experimental results that R_3/2 values did not decrease after silicification. Some process other than thermal degradation, possibly preservation of specific classes of biomolecules with low R_3/2 values, might have occurred during fossilization.     

Consumer acceptance of food crops developed by genome editing

One of the major problems regarding consumer acceptance of genetically modified organisms (GMOs) is the possibility that their transgenes could have adverse effects on the environment and/or human health. Genome editing, represented by the CRISPR/Cas9 system, can efficiently achieve transgene-free gene modifications and is anticipated to generate a wide spectrum of plants. However, the public attitude against GMOs suggests that people will initially be unlikely to accept these plants. We herein explored the bottlenecks of consumer acceptance of transgene-free food crops developed by genome editing and made some recommendations. People should not pursue a zero-risk bias regarding such crops. Developers are encouraged to produce cultivars with a trait that would satisfy consumer needs. Moreover, they should carefully investigate off-target mutations in resultant plants and initially refrain from agricultural use of multiplex genome editing for better risk–benefit communication. The government must consider their regulatory status and establish appropriate regulations if necessary. The government also should foster communication between the public and developers. If people are informed of the benefits of genome editing-mediated plant breeding and trust in the relevant regulations, and if careful risk–benefit communication and sincere considerations for the right to know approach are guaranteed, then such transgene-free crops could gradually be integrated into society.     

Conformational behavior of oxygenated mycobacterial mycolic acids from Mycobacterium bovis BCG

Phase diagrams of Langmuir monolayers of oxygenated mycolic acids, i.e. methoxy mycolic acid (MeO-MA), ketomycolic acid (Keto-MA), and artificially obtained deoxo-mycolic acid (deoxo-MA) from Mycobacterium bovis BCG were obtained by thermodynamic analysis of the surface pressure (pi) vs. average molecular area (A) isotherms. At lower temperatures and lower surface pressures, both Keto- and MeO-MAs formed rigid condensed monolayers where each MA molecule was considered to be in a 4-chain form, in which the three carbon chain segments due to bending of the 3-hydroxy aliphatic carboxylate chain and the 2-side chain were in compact parallel arrangement. At higher temperatures and surface pressures, MeO-MA and deoxo-MA tended to take stretched-out conformations in which the 3-hydroxy aliphatic carboxylate chain was more or less in an extended form, but Keto-MA retained the original 4-chain structure. The thickness measurement of the monolayers in situ by ellipsometry at different pi values and temperatures supported the above conclusions derived from the phase diagrams. The enthalpy changes associated with the phase transitions of MeO-MA and deoxo-MA implied that the MeO-MA needed larger energy to change from a compact conformation to an extended one, possibly and partly due to the dehydration of the methoxy group from water surface involved. Molecular dynamics studies of MA models derived from Monte Carlo calculations were also performed, which confirmed the conformational behavior of MAs suggested by the thermodynamic studies on the Langmuir monolayers.     

Two hydrophobic segments of the RTN1 family determine the ER localization and retention

Reticulon (RTN) proteins are localized to the endoplasmic reticulum (ER), and are related to intracellular membrane trafficking, apoptosis, inhibiting axonal regeneration, and Alzheimer's disease. The RTN proteins are produced without an N-terminal signal peptide. Their C-terminal domain contains two long hydrophobic segments. We analyzed the ER localization signal of human RTN1-A. Mutant proteins lacking the first (39 residues) or second (36 residues) hydrophobic segment showed ER localization. On the other hand, the mutant lacking both hydrophobic segments was cytosolic. Enhanced green fluorescent protein (EGFP) tagged with the first or second hydrophobic segment of RTN1-A was localized to the ER. These results suggest that each hydrophobic segment determines the ER localization. In addition, EGFP tagged with the truncated form of the first hydrophobic segment exhibited the localization to the Golgi rather than the ER. This suggests that the length of the hydrophobic segment contributes to the ER retention of RTN1-A.     

Morphological and physiological differences among cultivation lines of <Emphasis Type="Italic">Undaria pinnatifida</Emphasis> in a common garden experiment using a tank culture system

Undaria pinnatifida is grown for food and industrial materials worldwide; therefore, advanced breeding is needed to meet quality and productivity requirements. In this study, we examined regional lines of U. pinnatifida from five cultivation sites in Japan with different environmental conditions: Oga (OGA, the northern Sea of Japan coast), Hirota Bay (HRT, the northeastern Pacific coast), Matsushima Bay (MAT, the northeastern Pacific coast), Naruto (the Seto Inland Sea coast) and Shimonoseki (SIM, the southern Sea of Japan coast). The sporophytes of these lines were cultured in a tank culture system under controlled environmental conditions, and their morphological characteristics, nutrient uptake kinetics (V _max, K _s and V _max/K _s ), and carbon, nitrogen and phosphorus contents were determined. Sporophytes from MAT grew faster, whereas those from SIM were smaller than those from the other sites. Although the blade thickness of sporophytes cultivated in the sea significantly differs among cultivation sites in the previous study, there was no significant difference in blade thickness among the regional lines cultivated in the tank. Sporophytes from OGA had the greatest V _max/K _s values and significantly greater nitrogen contents than the other lines. Therefore, the morphological characteristics of MAT and SIM sporophytes, and the nutrient uptake kinetics of OGA sporophytes may have a genetic origin. This indicates that these lines may represent useful resources for selective breeding, with MAT sporophytes providing faster growth and OGA sporophytes being well-adapted to low-nutrient conditions.     

Core fucose and bisecting GlcNAc, the direct modifiers of the N-glycan core: their functions and target proteins

Among the various posttranslational modification reactions, glycosylation is the most common, and nearly 50% of all known proteins are thought to be glycosylated. In particular, most of the molecules involved in cell–cell communication are glycosylated, and glycosylation is thus implicated in many physiological and pathological events, including cell growth, cell–cell adhesion, and tumor metastasis. As many of the glycosyltransferases are cloned, it is becoming possible to alter the oligosaccharide structures artificially and examine the effects. Among the glycosyltransferases involved in the biosynthesis of N-glycan branching, this review will focus on the function of Fut8 and N-acetylglucosaminyltransferase III, which directly modify the N-glycan core. It is suggested that these two glycosyltransferases are involved in the conformation and the function of the modified proteins including cell-surface receptors and adhesion molecules.     

Mannose binding lectin and lung collectins interact with Toll-like receptor 4 and MD-2 by different mechanisms

Background

We have previously shown that lung collectins, surfactant protein A (SP-A) and surfactant protein D, interact with Toll-like receptor (TLR) 2, TLR4, or MD-2. Bindings of lung collectins to TLR2 and TLR4/MD-2 result in the alterations of signaling through these receptors, suggesting the immunomodulatory functions of lung collectins. Mannose binding lectin (MBL) is another collectin molecule which has structural homology to SP-A. The interaction between MBL and TLRs has not yet been determined.

Methods

We prepared recombinant MBL, and analyzed its bindings to recombinant soluble forms of TLR4 (sTLR4) and MD-2.

Results

MBL bound to sTLR4 and MD-2. The interactions were Ca²⁺-dependent and inhibited by mannose or monoclonal antibody against the carbohydrate-recognition domain of MBL. Treatment of sTLR4 or MD-2 by peptide N-glycosidase F significantly decreased the binding of MBL. SP-A bound to deglycosylated sTLR4, and this property did not change in chimeric molecules of SP-A/MBL in which Glu¹⁹⁵–Phe²²⁸ or Thr¹⁷⁴–Gly¹⁹⁴ of SP-A were replaced with the corresponding MBL sequences.

General Significance

These results suggested that MBL binds to TLR4 and MD-2 through the carbohydrate-recognition domain, and that oligosaccharide moieties of TLR4 and MD-2 are important for recognition by MBL. Since our previous studies indicated that lung collectins bind to the peptide portions of TLRs, MBL and lung collectins interact with TLRs by different mechanisms. These direct interactions between MBL and TLR4 or MD-2 suggest that MBL may modulate cellular responses by altering signals through TLRs.     

Greenhouse Gas Budget of a Cool-Temperate Deciduous Broad-Leaved Forest in Japan Estimated Using a Process-Based Model

A terrestrial ecosystem model, called the Vegetation Integrative Simulator for Trace gases model (VISIT), which fully integrates biogeochemical carbon and nitrogen cycles, was developed to simulate atmosphere–ecosystem exchanges of greenhouse gases (CO₂, CH₄, and N₂O), and to determine the global warming potential (GWP) taking into account the radiative forcing effect of each gas. The model was then applied to a cool-temperate deciduous broad-leaved forest in Takayama, central Japan (36°08′N, 137°25′E, 1420 m above sea level). Simulations were conducted at a daily time step from 1948 to 2008, using time-series meteorological and nitrogen deposition data. VISIT accurately captured the carbon and nitrogen cycles of this typical Japanese forest, as validated by tower and chamber flux measurements. During the last 10 years of the simulation, the model estimated that the forest was a net greenhouse gas sink, having a GWP equivalent of 1025.7 g CO₂ m⁻² y⁻¹, most of which (1016.9 g CO₂ m⁻² y⁻¹) was accounted for by net CO₂ sequestration into forest biomass regrowth. CH₄ oxidation by the forest soil made a small contribution to the net sink (11.9 g CO₂-eq. m⁻² y⁻¹), whereas N₂O emissions were a very small source (3.2 g CO₂-eq. m⁻² y⁻¹), as expected for a volcanic soil in a humid climate. Analysis of the sensitivity of GWP to changes in temperature, precipitation, and nitrogen deposition indicated that warming temperatures would decrease the size of the sink, mainly as a result of increased CO₂ release due to increased ecosystem respiration.