Mass trapping of the diamondback moth (Plutella xylostella L.) by a combination of its sex pheromone and allyl isothiocyanate in cabbage fields in southern Vietnam.

A lure composed of (Z)-11-hexadecenal, (Z)-11-hexadecenyl acetate, and (Z)-11-hexadecen-1-ol at a ratio of 5 : 5 : 1 at a dose of 0.01 mg was optimal for the attraction of the Vietnamese strain of the diamondback moth (DBM). The combination of the sex pheromone with a plant volatile, allyl isothiocyanate, significantly increased the attraction of the pheromone trap. Females were also attracted, but they were only about 2% of all moths captured. In plots with 120-130 traps per ha, mass trapping with the combined lures reduced the DBM larval densities in cabbage fields as effectively as the spraying of insecticides 6 to 8 times. The weekly trap catches indicated that DBM adult densities in the mass-trapping fields were low until 28 days after transplantation, and then were kept to a modest increase until day 49. This field study also shows that the trap catches were well correlated with the DBM larval densities.

DeepLabCut-based daily behavioural and posture analysis in a cricket.

Circadian rhythms are indispensable intrinsic programs that regulate the daily rhythmicity of physiological processes, such as feeding and sleep. The cricket has been employed as a model organism for understanding the neural mechanisms underlying circadian rhythms in insects. However, previous studies measuring rhythm-controlled behaviours only analysed locomotive activity using seesaw-type and infrared sensor-based actometers. Meanwhile, advances in deep learning techniques have made it possible to analyse animal behaviour and posture using software that is devoid of human bias and does not require physical tagging of individual animals. Here, we present a system that can simultaneously quantify multiple behaviours in individual crickets - such as locomotor activity, feeding, and sleep-like states - in the long-term, using DeepLabCut, a supervised machine learning-based software for body keypoints labelling. Our system successfully labelled the six body parts of a single cricket with a high level of confidence and produced reliable data showing the diurnal rhythms of multiple behaviours. Our system also enabled the estimation of sleep-like states by focusing on posture, instead of immobility time, which is a conventional parameter. We anticipate that this system will provide an opportunity for simultaneous and automatic prediction of cricket behaviour and posture, facilitating the study of circadian rhythms.

Bulk and In Situ Quantification of Coniferaldehyde Residues in Lignin.

Lignin is a group of cell wall localised heterophenolic polymers varying in the chemistry of the aromatic and aliphatic parts of its units. The lignin residues common to all vascular plants have an aromatic ring with one para hydroxy group and one meta methoxy group, also called guaiacyl (G). The terminal function of the aliphatic part of these G units, however, varies from alcohols, which are generally abundant, to aldehydes, which represent a smaller proportion of lignin monomers. The proportions of aldehyde to alcohol G units in lignin are, nevertheless, precisely controlled to respond to environmental and development cues. These G aldehyde to alcohol unit proportions differ between each cell wall layer of each cell type to fine-tune the cell wall biomechanical and physico-chemical properties. To precisely determine changes in lignin composition, we, herein, describe the various methods to detect and quantify the levels and positions of G aldehyde units, also called coniferaldehyde residues, of lignin polymers in ground plant samples as well as in situ in histological cross-sections.

History of the terrestrial isopod genus Ligidium in Japan based on phylogeographic analysis.

BACKGROUND: Phylogeographical approaches explain the genetic diversity of local organisms in the context of their geological and geographic environments. Thus, genetic diversity can be a proxy for geological history. Here we propose a genus of woodland isopod, Ligidium, as a marker of geological history in relation to orogeny and the Quaternary glacial cycle. RESULTS: Mitochondrial analysis of 721 individuals from 97 sites across Japan revealed phylogenetic divergence between the northeastern and southwestern Japan arcs. It also showed repeated population expansions in northeastern Japan in response to Quaternary glacial and interglacial cycles. Genome-wide analysis of 83 selected individuals revealed multiple genetic nuclear clusters. The genomic groupings were consistent with the local geographic distribution, indicating that the Ligidium phylogeny reflects its regional history. CONCLUSION: Ligidium DNA sequence analysis can provide insight into the geological, geographical, and paleoenvironmental history of the studied region.

Multiple episodes of ice loss from the Wilkes Subglacial Basin during the Last Interglacial.

The Last Interglacial (LIG: 130,000-115,000 years ago) was a period of warmer global mean temperatures and higher and more variable sea levels than the Holocene (11,700-0 years ago). Therefore, a better understanding of Antarctic ice-sheet dynamics during this interval would provide valuable insights for projecting sea-level change in future warming scenarios. Here we present a high-resolution record constraining ice-sheet changes in the Wilkes Subglacial Basin (WSB) of East Antarctica during the LIG, based on analysis of sediment provenance and an ice melt proxy in a marine sediment core retrieved from the Wilkes Land margin. Our sedimentary records, together with existing ice-core records, reveal dynamic fluctuations of the ice sheet in the WSB, with thinning, melting, and potentially retreat leading to ice loss during both early and late stages of the LIG. We suggest that such changes along the East Antarctic Ice Sheet margin may have contributed to fluctuating global sea levels during the LIG.

Decadal-centennial-scale solar-linked climate variations and millennial-scale internal oscillations during the Early Cretaceous.

Understanding climate variability and stability under extremely warm 'greenhouse' conditions in the past is essential for future climate predictions. However, information on millennial-scale (and shorter) climate variability during such periods is scarce, owing to a lack of suitable high-resolution, deep-time archives. Here we present a continuous record of decadal- to orbital-scale continental climate variability from annually laminated lacustrine deposits formed during the late Early Cretaceous (123-120 Ma: late Barremian-early Aptian) in southeastern Mongolia. Inter-annual changes in lake algal productivity for a 1091-year interval reveal a pronounced solar influence on decadal- to centennial-scale climatic variations (including the ~ 11-year Schwabe cycle). Decadally-resolved Ca/Ti ratios (proxy for evaporation/precipitation changes) for a ~ 355-kyr long interval further indicate millennial-scale (~ 1000-2000-yr) extreme drought events in inner-continental areas of mid-latitude palaeo-Asia during the Cretaceous. Millennial-scale oscillations in Ca/Ti ratio show distinct amplitude modulation (AM) induced by the precession, obliquity and short eccentricity cycles. Similar millennial-scale AM by Milankovitch cycle band was also previously observed in the abrupt climatic oscillations (known as Dansgaard-Oeschger events) in the 'intermediate glacial' state of the late Pleistocene, and in their potential analogues in the Jurassic 'greenhouse'. Our findings indicate that external solar activity forcing was effective on decadal-centennial timescales, whilst the millennial-scale variations were likely amplified by internal process such as changes in deep-water formation strength, even during the Cretaceous 'greenhouse' period.

Lipid droplets in the pheromone glands of bombycids: Effects of larval diet on their size and pheromone titer.

In addition to the blend ratio, the quantity of sex pheromone components secreted by female moths may affect the efficient attraction of conspecific males. The present study using the silkmoth Bombyx mori, which has bombykol as its pheromone component, demonstrated that pheromone titer, body weight, and lipid droplet (LD) diameter in the pheromone gland were affected by the larval diet. Although the artificial diet contained approximately 11-fold more total fatty acids than mulberry leaf, the pheromone titer in the group fed the artificial diet (group AD) was approximately 2-fold higher than that of the group fed mulberry (group M). The diameter of LDs, which store the pheromone-precursor fatty acyl, E10,Z12-16:Acyl, was also larger in the AD group. The relatively small increase in sex pheromone titer by feeding on a fatty-acid-rich diet may be partly attributable to the storage of excess precursors in the LDs. We detected LDs in the pheromone glands of Trilocha varians, the closest non-congener of B. mori available in Bombycidae. T. varians uses bombykal and bombykyl acetate as sex pheromone components, which are biosynthesized via the same precursor fatty acyl as that of B. mori. The presence of LDs in T. varians suggests that the storage and mobilization mechanisms of the pheromone precursor fatty acyl via LDs may be conserved in bombycids.

Identification of a unique three-component sex pheromone produced by the tea black tussock moth, Dasychira baibarana (Lepidoptera: Erebidae: Lymantriinae).

BACKGROUND: The tea black tussock moth Dasychira baibarana Matsumura is a devastating pest in tea plantations that causes substantial economic losses. Presently, there is no effective method to control this pest other than pesticide application. The identified sex pheromone of D. baibarana could be used for detecting and monitoring this pest. RESULTS: Gas chromatography-electroantennogram detection showed that D. baibarana male moth antennae responded strongly to three components in the female sex pheromone gland, which were identified as: (3Z,6Z)-cis-9,10-epoxyhenicosa-3,6-diene (Z3,Z6,epo9-21:H) (I), (3Z,6Z,11E)-cis-9,10-epoxyhenicosa-3,6,11-triene (Z3,Z6,epo9,E11-21:H) (II) and (3Z,6Z)-henicosa-3,6-dien-11-one (Z3,Z6-21:11-one) (III). Dasychira baibarana uses a unique composition of an epoxydiene, epoxytriene, and dienone with the same 3,6-dienyl motif as its sex pheromone. The epoxytriene and dienone were not previously characterized as insect pheromone components. Electroantennogram analysis showed that each synthetic compound strongly stimulated male antennae, and compounds II and III elicited stronger responses than compound I. A wind tunnel bioassay and field trapping experiments proved that, ternary blends of compounds I-III attracted D. baibarana. Efficient attraction was achieved with a rubber septum baited with 500 µg of a mixture of compounds I-III at the ratio 25:20:55. CONCLUSION: The three identified compounds elicited an electroantennogram response in D. baibarana male moth antennae, and a mixture of the three components at the ratio 25:20:55 attracted D. baibarana male moths in a wind tunnel assay and field trapping experiments. This blend could be used for integrated management of D. baibarana in tea plantations. © 2022 Society of Chemical Industry.

Rerouting of the lignin biosynthetic pathway by inhibition of cytosolic shikimate recycling in transgenic hybrid aspen.

Lignin is a phenolic polymer deposited in the plant cell wall, and is mainly polymerized from three canonical monomers (monolignols), i.e. p-coumaryl, coniferyl and sinapyl alcohols. After polymerization, these alcohols form different lignin substructures. In dicotyledons, monolignols are biosynthesized from phenylalanine, an aromatic amino acid. Shikimate acts at two positions in the route to the lignin building blocks. It is part of the shikimate pathway that provides the precursor for the biosynthesis of phenylalanine, and is involved in the transesterification of p-coumaroyl-CoA to p-coumaroyl shikimate, one of the key steps in the biosynthesis of coniferyl and sinapyl alcohols. The shikimate residue in p-coumaroyl shikimate is released in later steps, and the resulting shikimate becomes available again for the biosynthesis of new p-coumaroyl shikimate molecules. In this study, we inhibited cytosolic shikimate recycling in transgenic hybrid aspen by accelerated phosphorylation of shikimate in the cytosol through expression of a bacterial shikimate kinase (SK). This expression elicited an increase in p-hydroxyphenyl units of lignin and, by contrast, a decrease in guaiacyl and syringyl units. Transgenic plants with high SK activity produced a lignin content comparable to that in wild-type plants, and had an increased processability via enzymatic saccharification. Although expression of many genes was altered in the transgenic plants, elevated SK activity did not exert a significant effect on the expression of the majority of genes responsible for lignin biosynthesis. The present results indicate that cytosolic shikimate recycling is crucial to the monomeric composition of lignin rather than for lignin content.

The significance of pyrogenic polycyclic aromatic hydrocarbons in Borneo peat core for the reconstruction of fire history.

The reconstruction of fire history is essential to understand the palaeoclimate and human history. Polycyclic aromatic hydrocarbons (PAHs) have been extensively used as a fire marker. In this work, the distribution of PAHs in Borneo peat archives was investigated to understand how PAHs reflect the palaeo-fire activity. In total, 52 peat samples were analysed from a Borneo peat core for the PAH analysis. Pyrogenic PAHs consist of 2-7 aromatic rings, some of which have methyl and ethyl groups. The results reveal that the concentration of pyrogenic PAHs fluctuated with the core depth. Compared to low-molecular-weight (LMW) PAHs, the high-molecular-weight (HMW) PAHs had a more similar depth variation to the charcoal abundance. This finding also suggests that the HMW PAHs were mainly formed at a local fire near the study area, while the LMW PAHs could be transported from remote locations.

Remote and local drivers of Pleistocene South Asian summer monsoon precipitation: A test for future predictions.

South Asian precipitation amount and extreme variability are predicted to increase due to thermodynamic effects of increased 21st-century greenhouse gases, accompanied by an increased supply of moisture from the southern hemisphere Indian Ocean. We reconstructed South Asian summer monsoon precipitation and runoff into the Bay of Bengal to assess the extent to which these factors also operated in the Pleistocene, a time of large-scale natural changes in carbon dioxide and ice volume. South Asian precipitation and runoff are strongly coherent with, and lag, atmospheric carbon dioxide changes at Earth's orbital eccentricity, obliquity, and precession bands and are closely tied to cross-equatorial wind strength at the precession band. We find that the projected monsoon response to ongoing, rapid high-latitude ice melt and rising carbon dioxide levels is fully consistent with dynamics of the past 0.9 million years.

Quantum approach for nanoparticle fluorescence by sub-ns photon detection.

Well defined detection and analysis of nanoparticle-sized samples such as extracellular vesicles or viruses may be important for potential disease diagnostics. However, using conventional flow-cytometry optical methods to evaluate such small particles is quite challenging. The reason is that the particle is smaller than the diffraction limit, making detection difficult. An alternative approach is fluorescence detection via conjugated fluorochromes attached to the nanoparticles; the challenge in this case is the limitation imposed upon detection of a very small number of emitted photons buried in high background photon counts. Emitted fluorescence is described by the well-known equation kf = σa I Q, which describes the emitted fluorescence rate (kf) (photons/s) as the multiplication of molecular absorption cross section(σa), excitation intensity (I), and quantum yield (Q). In addition, the excitation rate is equal to 1/t, which is the inverse of the lifetime of several ns representing the most typical conjugated fluorescent molecules used in flow cytometry. We recently developed a sub-ns photon sensor that is faster than most fluorescence lifetimes, since sub-ns speed is a critically important parameter for the separation of individual emitted photons. Based on our observation of fluorescence and background levels on typical commercial flow cytometers it is evident that a significant component of the background is induced by water-molecular vibrations. Therefore, understanding what constitutes all the components that contribute to the signals we measure in flow cytometry would help in defining what we currently call "background signals." We attempted to define a theoretical model to try to unravel these issues. This model was based on use of a reflective dry surface in the absence of water molecules. Our objective was to determine if it is possible to minimize background and enhance signal, and to provide valuable information on the contributing components of the signals collected. In order to test this model, we tested a single dried particle 50 nm in diameter on a reflective surface with minimum background. While this is clearly not a standard biological system, our results suggest that this quantum approach closely follows established photon base theory. Our goal was to define the parameters for practical nanoparticle-fluorescence analysis while enhancing our knowledge of the contribution of background properties.

Semiochemicals containing lepidopteran sex pheromones: Wonderland for a natural product chemist.

Since the first identification of bombykol, sex pheromones of about 700 moth species have been elucidated. Additionally, field evaluations of synthetic pheromones and their related compounds have revealed the male attraction of another 1,300 species. These pheromones and attractants are listed on the web-sites, "Pheromone Database, Part I." Pheromone components are classified according to their chemical structures into two major groups (Types I and II) and miscellaneous. Based on our previous review published in 2004, studies reported during the last two decades are highlighted here to provide information on the structure characteristics of newly identified pheromones, current techniques for structure determination, new enantioselective syntheses of methyl-branched pheromones, and the progress of biosynthetic research. Besides the moth sex pheromones, various pheromones and allomones from many arthropod species have been uncovered. These semiochemicals are being collected in the "Pheromone Database, Part II." The chemical diversity provides a wonderland for natural product chemists.

Genetic Diversity of Ligidium Isopods in Hokkaido and Niigata, Northern Japan, Based on Mitochondrial DNA Analysis.

The genetic diversity of the genus Ligidium in Hokkaido and Niigata, northern Japan, was investigated by analyzing the cytochrome c oxidase subunit 1 (CO1) region in the mitochondrial DNA (mtDNA). The genetic diversity in Hokkaido was much lower than that in Niigata. Nine different operational taxonomic units (OTUs) were identified. Only a single OTU, most likely Ligidium japonicum, was found in Hokkaido, whereas all nine OTUs were found in Niigata. Using the mtDNA evolutionary rate determined for the marine invertebrate Haptosquilla pulchella (Miers, 1880), population expansion for OTU1 in Hokkaido was estimated to have occurred at 12,600 years BP, suggesting that Ligidium underwent a bottleneck due to glacial cooling, and the population then expanded after postglacial warming. Assuming that the expansion of the OTU1 population occurred at 9600 years BP, when the sea surface temperature rose offshore of Tokachi in the Northwestern Pacific, the evolutionary rate (µ) of the mtDNA CO1 region in Ligidium is calculated as: 0.087 (95% confidence intervals: min: 0.042-max: 0.12) (substitutions/site/million years). The presence of a haplotype common to Hokkaido and Niigata implies that the haplotype migrated across the Tsugaru Strait. Considering that geological evidence indicates that the Tsugaru Strait was continuously present even during the last glacial maximum when the sea level was at its lowest, accidental transport by human beings or animals might have been critical to the migration of Ligidium.

Importance of Lignin Coniferaldehyde Residues for Plant Properties and Sustainable Uses.

Increases in coniferaldehyde content, a minor lignin residue, significantly improves the sustainable use of plant biomass for feed, pulping, and biorefinery without affecting plant growth and yields. Herein, different analytical methods are compared and validated to distinguish coniferaldehyde from other lignin residues. It is shown that specific genetic pathways regulate amount, linkage, and position of coniferaldehyde within the lignin polymer for each cell type. This specific cellular regulation offers new possibilities for designing plant lignin for novel and targeted industrial uses.

Identification of enzymatic genes with the potential to reduce biomass recalcitrance through lignin manipulation in Arabidopsis.

BACKGROUND: During the chemical and biochemical decomposition of lignocellulosic biomasses, lignin is highly recalcitrant. Genetic transformation of plants to qualitatively and/or quantitatively modify lignin may reduce these recalcitrant properties. Efficient discovery of genes to achieve lignin manipulation is thus required. RESULTS: To screen for new genes to reduce lignin recalcitrance, we heterologously expressed 50 enzymatic genes under the control of a cinnamate 4-hydroxylase (C4H) gene promoter, derived from a hybrid aspen, which is preferentially active in tissues with lignified cell walls in Arabidopsis plants. These genes encode enzymes that act on metabolites in shikimate, general phenylpropanoid, flavonoid, or monolignol biosynthetic pathways. Among these genes, 30, 18, and 2 originated from plants, bacteria, and fungi, respectively. In our first screening step, 296 independent transgenic plants (T1 generation) harboring single or multiple transgenes were generated from pools of seven Agrobacterium strains used for conventional floral-dip transformation. Wiesner and Mäule staining patterns in the stems of the resultant plants revealed seven and nine plants with apparent abnormalities in the two respective staining analyses. According to genomic PCR and subsequent direct sequencing, each of these 16 plants possessed a gene encoding either coniferaldehyde dehydrogenase (calB), feruloyl-CoA 6'-hydroxylase (F6H1), hydroxycinnamoyl-CoA hydratase/lyase (couA), or ferulate 5-hydroxylase (F5H), with one transgenic plant carrying both calB and F6H1. The effects of these genes on lignin manipulation were confirmed in individually re-created T1 transgenic Arabidopsis plants. While no difference in lignin content was detected in the transgenic lines compared with the wild type, lignin monomeric composition was changed in the transgenic lines. The observed compositional change in the transgenic plants carrying calB, couA, and F5H led to improved sugar release from cell walls after alkaline pretreatment. CONCLUSIONS: Simple colorimetric characterization of stem lignin is useful for simultaneous screening of many genes with the potential to reduce lignin recalcitrance. In addition to F5H, the positive control, we identified three enzyme-coding genes that can function as genetic tools for lignin manipulation. Two of these genes (calB and couA) accelerate sugar release from transgenic lignocelluloses.

Functional characterization of the epoxidase gene, Li_epo1 (CYP341B14), involved in generation of epoxyalkene pheromones in the mulberry tiger moth Lemyra imparilis.

Epoxidation of alkenes derived from essential fatty acids is a key step in the biosynthesis of sex pheromones in moth species that utilize alkenyl sex pheromones. The position of the epoxy ring in the pheromone molecule differs depending on the species, thereby conferring diversities on sex pheromones. To date, only one pheromone gland (PG)-specific epoxidase, Hc_epo1 (CYP341B14), has been reported. Hc_epo1, which was identified from an arctiid moth Hyphantria cunea, catalyzes the epoxidation of a double bond at position 9 of the triene, Z3,Z6,Z9-21:H. In the present study, we investigated the PG-specific epoxidase from another arctiid, the mulberry tiger moth Lemyra imparilis, in order to verify whether cytochrome P450 in the CYP341B subfamily, to which Hc_epo1 belongs to, is responsible for the epoxidation of pheromone precursors at position 9 in moths other than H. cunea. A fragment of the Hc_epo1 homolog was amplified from cDNA prepared from the PG of L. imparilis by PCR with degenerate primers. The deduced amino acid sequence of the subsequently cloned homolog, Li_epo1, showed 88.5% identity to Hc_epo1. A functional assay using the Sf9 insect cell line-baculovirus expression system showed that Li_epo1 exhibited epoxidase activity with high selectivity to the double bond at position 9 of two trienes, Z3,Z6,Z9-21:H and Z3,Z6,Z9-23:H, precursors of epoxy diene sex pheromone components in L. imparilis.

Identification and field attraction of the female sex pheromone of a kiwifruit pest, Nokona feralis (Lepidoptera: Sesiidae).

Female sex pheromone of a clearwing moth Nokona feralis (Leech) (Lepidoptera: Sesiidae), a pest of kiwifruit, was identified to be a 7:3 mixture of (3E,13Z)-3,13-octadecadienyl acetate (E3,Z13-18:OAc) and (3E,13Z)-3,13-octadecadien-1-ol (E3,Z13-18:OH) by GC-EAD and GC/MS analyses. Males were attracted to wide-range mixtures of E3,Z13-18:OAc and E3,Z13-18:OH, and a 7:3 mixture of those two compounds strongly attracted the males in the field.

Phylogenetic diversity and distribution of bacterial and archaeal amoA genes in the East China Sea during spring.

Microbial nitrification is a key process in the nitrogen cycle in the continental shelf ecosystems. The genotype compositions and abundance of the ammonia monooxygenase gene, amoA, derived from ammonia-oxidizing archaea (AOA) and bacteria (AOB) in two size fractions (2-10 and 0.2-2 µm), were investigated in the East China Sea (ECS) in May 2008 using PCR-denaturing gradient gel electrophoresis (DGGE) and quantitative PCR (qPCR). Four sites were selected across the continental shelf edge: continental shelf water (CSW), Kuroshio branch water (KBW), transition between CSW and KBW (TCSKB) and coastal KBW (CKBW). The gene copy numbers of AOA-amoA were higher than those of AOB-amoA in ECS. The relative abundance of amoA to the total 16S rRNA gene level reached approximately 15% in KBW and CKBW for the free-living fraction of AOA, whereas the level was less than 0.01% throughout ECS for the AOB. A cluster analysis of the AOA-amoA-DGGE band pattern showed distinct genotype compositions in CSW in both the size fractions and in the surface of the TCSKB and KBW. Sequences of the DGGE bands were assigned to two clades. One of the clades exclusively consisted of sequences derived from the 2-10-µm fraction. This study revealed that AOA-amoA abundance dominated over AOB-amoA throughout the ECS, whereas the genotype composition of AOA-amoA were distributed heterogeneously across the water masses. Additionally, this is the first report showing the distribution of AOA-amoA genotypes characteristic to particle-associated AOA in the offshore of the East China Sea.