Synthesis of Very-Long-Chain Fatty Acids in the Epidermis Controls Plant Organ Growth by Restricting Cell Proliferation

Plant organ growth is controlled by inter-cell-layer communication, which thus determines the overall size of the organism. The epidermal layer interfaces with the environment and participates in both driving and restricting growth via inter-cell-layer communication. However, it remains unknown whether the epidermis can send signals to internal tissue to limit cell proliferation in determinate growth. Very-long-chain fatty acids (VLCFAs) are synthesized in the epidermis and used in the formation of cuticular wax. Here we found that VLCFA synthesis in the epidermis is essential for proper development of Arabidopsis thaliana. Wild-type plants treated with a VLCFA synthesis inhibitor and pasticcino mutants with defects in VLCFA synthesis exhibited overproliferation of cells in the vasculature or in the rib zone of shoot apices. The decrease of VLCFA content increased the expression of IPT3, a key determinant of cytokinin biosynthesis in the vasculature, and, indeed, elevated cytokinin levels. These phenotypes were suppressed in ipt3;5;7 triple mutants, and also by vasculature-specific expression of cytokinin oxidase, which degrades active forms of cytokinin. Our results imply that VLCFA synthesis in the epidermis is required to suppress cytokinin biosynthesis in the vasculature, thus fine-tuning cell division activity in internal tissue, and therefore that shoot growth is controlled by the interaction between the surface (epidermis) and the axis (vasculature) of the plant body.     

Traveling EEG slow oscillation along the dorsal attention network initiates spontaneous perceptual switching

An ambiguous figure such as the Necker cube causes spontaneous perceptual switching (SPS). The mechanism of SPS in multistable perception has not yet been determined. Although early psychological studies suggested that SPS may be caused by fatigue or satiation of orientation, the neural mechanism of SPS is still unknown. Functional magnetic resonance imaging (fMRI) has shown that the dorsal attention network (DAN), which mainly controls voluntary attention, is involved in bistable perception of the Necker cube. To determine whether neural dynamics along the DAN cause SPS, we performed simultaneous electroencephalography (EEG) and fMRI during an SPS task with the Necker cube, with every SPS reported by pressing a button. This EEG–fMRI integrated analysis showed that (a) 3–4 Hz spectral EEG power modulation at fronto-central, parietal, and centro-parietal electrode sites sequentially appeared from 750 to 350 ms prior to the button press; and (b) activations correlating with the EEG modulation traveled along the DAN from the frontal to the parietal regions. These findings suggest that slow oscillation initiates SPS through global dynamics along the attentional system such as the DAN.     

High-efficiency cloning of Arabidopsis full-length cDNA by biotinylated CAP trapper

Full-length cDNAs are essential for functional analysis of plant genes. We constructed high-content, full-length cDNA libraries from Arabidopsis thaliana plants based on chemical introduction of a biotin group into the diol residue of the CAP structure of eukaryotic mRNA, followed by RNase I treatment, to select full-length cDNA. More than 90% of the total clones obtained were of full length; recombinant clones were obtained with high efficiency (2.2 × 10⁶/9 μg starting mRNA). Sequence analysis of 111 randomly picked clones indicated that 32 isolated cDNA groups were derived from novel genes in the A. thaliana genome.     

Computational chemical analysis of Ru(II)‐Pheox–catalyzed highly enantioselective intramolecular cyclopropanation reactions

Computational chemical analysis of Ru(II)‐Pheox–catalyzed highly enantioselective intramolecular cyclopropanation reactions was performed using density functional theory (DFT). In this study, cyclopropane ring–fused γ‐lactones, which are 5.8 kcal/mol more stable than the corresponding minor enantiomer, are obtained as the major product. The results of the calculations suggest that the enantioselectivity of the Ru(II)‐Pheox–catalyzed intramolecular cyclopropanation reaction is affected by the energy differences between the starting structures 5l and 5i . The reaction pathway was found to be a stepwise mechanism that proceeds through the formation of a metallacyclobutane intermediate. This is the first example of a computational chemical analysis of enantioselective control in an intramolecular carbene‐transfer reaction using C₁‐symmetric catalysts.     

Hepatic neuroendocrine carcinoma in a Japanese macaque (Macaca fuscata)

Primary neuroendocrine neoplasm of the liver is extremely rare in both humans and non‐human primates. The present report describes the clinical and pathological findings of an aged Japanese macaque (Macaca fuscata) with hepatic neuroendocrine carcinoma. To our knowledge, this is the first report of hepatic neuroendocrine neoplasm in macaques.     

TiLIA: a software package for image analysis of firefly flash patterns

As flash signaling patterns of fireflies are species specific, signal‐pattern analysis is important for understanding this system of communication. Here, we present time‐lapse image analysis (TiLIA), a free open‐source software package for signal and flight pattern analyses of fireflies that uses video‐recorded image data. TiLIA enables flight path tracing of individual fireflies and provides frame‐by‐frame coordinates and light intensity data. As an example of TiLIA capabilities, we demonstrate flash pattern analysis of the fireflies Luciola cruciata and L. lateralis during courtship behavior.     

Two forms of secreted and thermostable luciferases from the marine copepod crustacean, Metridia pacifica

We cloned two forms of the secreted and thermostable luciferase genes, MpLuc1 and MpLuc2, from the marine copepod, Metridia pacifica. The 840-bp MpLuc1 cDNA comprised a 630-bp open reading frame encoding a 210-amino acid polypeptide (22.7 kDa). MpLuc1 had the closest homology with Metridia longa luciferase. The 753-bp MpLuc2 cDNA consisted of a 567-bp open reading frame (20.3 kDa), and it had the closest homology with Gaussia princeps luciferase. Single-specimen genomic PCR confirmed the presence of two luciferase genes in M. pacifica, and single-specimen RT-PCR revealed that both luciferase mRNAs were expressed. Both MpLuc1 and MpLuc2 (MpLucs) specifically reacted with the substrate coelenterazine producing identical bioluminescent spectra (lambdamax, 485 nm), but with different kinetics. Adding salt such as MgCl2 and CaCl2 to the reaction mixture significantly enhanced MpLuc1 and MpLuc2 activities. Wild-type MpLucs were remarkably thermostable; MpLuc1 retained about 60% of the original activity even after incubation at 90 degrees C for 30 min. MpLucs expressed in NIH-3T3 and HeLa cells were largely secreted into the culture medium. Continuous monitoring of secreted MpLuc1 driven by the c-fos promoter demonstrated the potential usefulness of MpLuc1 in nondisruptive reporter assays.     

Farnesyltransferase inhibitor improved survival following endotoxin challenge in mice

Endotoxemia plays an important role in the pathogenesis of sepsis and is accompanied by dysregulated apoptosis of immune and non-immune cells. Treatment with statins reduces mortality in rodent models of sepsis and endotoxemia. Inhibition of protein isoprenylation, including farnesylation, has been proposed as a mechanism to mediate the lipid-lowering-independent effects of statins. Nonetheless, the effects of the inhibition of isoprenylation have not yet been studied. To investigate the role of farnesylation, we evaluated the effects of farnesyltransferase inhibitor and statin on survival following lipopolysaccharide (LPS) challenge in mice. Both simvastatin (2 mg/kg BW) and FTI-277 (20 mg/kg BW) treatment improved survival by twofold after LPS injection, as compared with vehicle alone (p < 0.01). LPS-induced cleavage (activation) of caspase-3, an indicator of apoptotic change, and increased protein expression of proapoptotic molecules, Bax and Bim, and activation of c-Jun NH₂-terminal kinase (JNK/SAPK) in the liver and spleen were attenuated by both simvastatin and FTI-277. These results demonstrate that farnesyltransferase inhibitor as well as statin significantly reduced LPS-induced mortality in mice. Our findings also suggest that inhibition of protein farnesylation may contribute to the lipid-lowering-independent protective effects of statins in endotoxemia, and that protein farnesylation may play a role in LPS-induced stress response, including JNK/SAPK activation, and apoptotic change. Our data argue that farnesyltransferase may be a potential molecular target for treating patients with endotoxemia.     

Factors associated with severity of daytime sleepiness and indications for initiating treatment in patients with periodic limb movements during sleep

Obstructive sleep apnea syndrome (OSAS) is closely associated with hypertension. Activity of angiotensin II (Ang II) and non-dipping nocturnal blood pressure (BP) variability are implicated in hypertension-related target organ damage. We examined the correlation between OSAS with serum Ang II levels and evaluated the risk of non-dipping BP variability in 180 patients with essential hypertension (EHT). Eligible patients were divided into three subgroups based on their apnea-hypopnea index (AHI) evaluated by polysomnography. EHT alone, EHT with mild OSAS, and EHT with moderate/severe OSAS. Ambulatory BP monitoring was used to calculate mean BP over 24 h, as well as diurnal and nocturnal BP variability. Serum Ang II was determined with enzyme-linked immun-osorbent assay. EHT patients with OSAS had significantly higher systolic BP calculated either over 24 h, or by diurnal or nocturnal monitoring (P < 0.05). More EHT patients with OSAS showed non-dipping BP profiles than did EHT patients alone (P < 0.05). The number of patients with non-dipping BP increased with increasing OSAS severity. Surgical treatment alleviated OSAS and reduced AHI (P < 0.05). Preoperative serum Ang II in EHT patients with OSAS was significantly higher than that in those without OSAS (P < 0.05), and showed a rising trend with OSAS severity (P < 0.05). Postoperative serum Ang II, BP and the incidence of non-dipping BP were reduced by surgery to levels lower than preoperative values in patients with OSAS. We therefore conclude that OSAS leads to increased serum Ang II and increased risk of non-dipping BP in patients with EHT.