Palatability and feeding preferences of Uresiphita maorialis (Lepidoptera: Crambidae) for three Sophora species

In a three-hour bioassay, we tested the palatability and feeding preferences of Uresiphita maorialis (kōwhai moth) for Sophora tetraptera, Sophora microphylla and Sophora prostrata. Palatability tests showed no differences among the Sophora species. Feeding preferences, on the other hand, showed that S. tetraptera and S. microphylla leaves are preferred over S. prostrata leaves. Our results support our field observations in Wellington city parks and gardens showing that S. tetraptera and S. microphylla plants frequently have higher densities of larvae than S. prostrata.     

Predator faunas past and present: quantifying the influence of waterborne cues in divergent ecotypes of the isopod Asellus aquaticus

Waterborne chemical cues are an important source of information for many aquatic organisms, in particular when assessing the current risk of predation. The ability to use chemical cues to detect and respond to potential predators before an actual encounter can improve prey chances of survival. We investigated predator recognition and the impact of chemical cues on predator avoidance in the freshwater isopod Asellus aquaticus. This isopod has recently colonised a novel habitat and diverged into two distinct ecotypes, which encounter different predator communities. Using laboratory-based choice experiments, we have quantified behavioural responses to chemical cues from predators typical of the two predator communities (larval dragonflies in the ancestral habitat, perch in the newly colonised habitat) in wild-caught and lab-reared Asellus of the two ecotypes. Individuals with prior experience of predators showed strong predator avoidance to cues from both predator types. Both ecotypes showed similar antipredator responses, but sexes differed in terms of threat-sensitive responses with males avoiding areas containing predator cues to a larger extent than females. Overall, chemical cues from fish elicited stronger predator avoidance than cues from larval dragonflies. Our results indicate that in these isopods, prior exposure to predators is needed to develop antipredator behaviour based on waterborne cues. Furthermore, the results emphasise the need to analyse predator avoidance in relation to waterborne cues in a sex-specific context, because of potential differences between males and females in terms of vulnerability and life history strategies.     

Effects of Intercellular Junction Protein Expression on Intracellular Ice Formation in Mouse Insulinoma Cells

The development of cryopreservation procedures for tissues has proven to be difficult in part because cells within tissue are more susceptible to intracellular ice formation (IIF) than are isolated cells. In particular, previous studies suggest that cell-cell interactions increase the likelihood of IIF by enabling propagation of ice between neighboring cells, a process thought to be mediated by gap junction channels. In this study, we investigated the effects of cell-cell interactions on IIF using three genetically modified strains of the mouse insulinoma cell line MIN6, each of which expressed key intercellular junction proteins (connexin-36, E-cadherin, and occludin) at different levels. High-speed video cryomicroscopy was used to visualize the freezing process in pairs of adherent cells, revealing that the initial IIF event in a given cell pair was correlated with a hitherto unrecognized precursor phenomenon: penetration of extracellular ice into paracellular spaces at the cell-cell interface. Such paracellular ice penetration occurred in the majority of cell pairs observed, and typically preceded and colocalized with the IIF initiation events. Paracellular ice penetration was generally not observed at temperatures >−5.65°C, which is consistent with a penetration mechanism via defects in tight-junction barriers at the cell-cell interface. Although the maximum temperature of paracellular penetration was similar for all four cell strains, genetically modified cells exhibited a significantly higher frequency of ice penetration and a higher mean IIF temperature than did wild-type cells. A four-state Markov chain model was used to quantify the rate constants of the paracellular ice penetration process, the penetration-associated IIF initiation process, and the intercellular ice propagation process. In the initial stages of freezing (>−15°C), junction protein expression appeared to only have a modest effect on the kinetics of propagative IIF, and even cell strains lacking the gap junction protein connexin-36 exhibited nonnegligible ice propagation rates.     

Cytidine derivatives as IspF inhibitors of Burkolderia pseudomallei

Published biological data suggest that the methyl erythritol phosphate (MEP) pathway, a non-mevalonate isoprenoid biosynthetic pathway, is essential for certain bacteria and other infectious disease organisms. One highly conserved enzyme in the MEP pathway is 2C-methyl-d-erythritol 2,4-cyclodiphosphate synthase (IspF). Fragment-bound complexes of IspF from Burkholderia pseudomallei were used to design and synthesize a series of molecules linking the cytidine moiety to different zinc pocket fragment binders. Testing by surface plasmon resonance (SPR) found one molecule in the series to possess binding affinity equal to that of cytidine diphosphate, despite lacking any metal-coordinating phosphate groups. Close inspection of the SPR data suggest different binding stoichiometries between IspF and test compounds. Crystallographic analysis shows important variations between the binding mode of one synthesized compound and the pose of the bound fragment from which it was designed. The binding modes of these molecules add to our structural knowledge base for IspF and suggest future refinements in this compound series.     

Structure and content of pollutants in temporal surface sediments in small watersheds

ABSTRACT

Formation of gel-like surface sediments has been observed during spring and autumn in small watersheds in boreal areas with pH <5.7 and concentrations of humic substances above 3 mg L^?1. This structure efficiently accumulates dissolved, colloidal and particulate constituents. The gel consists of ferric (hydr)oxides and fulvic acid and has high viable counts of bacteria (notably Gallionella spp.) as well as fungal hyphae. The solid/solution distribution (log K_d; l kg^?1) for trace metals (Cd, Cu, Pb, V, Zn) ranges from 4 to 6.5 which indicate an efficient accumulation during periods with gel. The concentrations of adsorbable organic halogens in the gel were not different from forest soils in general.     

Evaluation of dental enamel caries assessment using Quantitative Light Induced Fluorescence and Optical Coherence Tomography

An in vitro study of morphological alterations between sound dental structure and artificially induced white spot lesions in human teeth, was performed through the loss of fluorescence by Quantitative Light‐Induced Fluorescence (QLF) and the alterations of the light attenuation coefficient by Optical Coherence Tomography (OCT). To analyze the OCT images using a commercially available system, a special algorithm was applied, whereas the QLF images were analyzed using the software available in the commercial system employed. When analyzing the sound region against white spot lesions region by QLF, a reduction in the fluorescence intensity was observed, whilst an increase of light attenuation by the OCT system occurred. Comparison of the percentage of alteration between optical properties of sound and artificial enamel caries regions showed that OCT processed images through the attenuation of light enhanced the tooth optical alterations more than fluorescence detected by QLF System.

QLF versus OCT imaging of enamel caries: a photonics assessment     

Detection of long non-coding RNAs in human breastmilk extracellular vesicles: Implications for early child development

Breastmilk has many documented beneficial effects on the developing human infant, but the components of breastmilk that influence these developmental pathways have not been fully elucidated. Increasing evidence suggests that non-coding RNAs encapsulated in extracellular vesicles (EVs) represent an important mechanism of communication between the mother and child. Long non-coding RNAs (lncRNAs) are of particular interest given their key role in gene expression and development. However, it is not known whether breastmilk EVs contain lncRNAs. We used qRT-PCR to determine whether EVs isolated from human breastmilk contain lncRNAs previously reported to be important for developmental processes. We detected 55 of the 87 screened lncRNAs in EVs from the 30 analyzed breastmilk samples, and CRNDE, DANCR, GAS5, SRA1 and ZFAS1 were detected in >90% of the samples. GAS5, SNHG8 and ZFAS1 levels were highly correlated (Spearman's rho > 0.9; P < 0.0001), which may indicate that the loading of these lncRNAs into breastmilk EVs is regulated by the same pathways. The detected lncRNAs are important epigenetic regulators involved in processes such as immune cell regulation and metabolism. They may target a repertoire of recipient cells in offspring and could be essential for child development and health. Further experimental and epidemiological studies are warranted to determine the impact of breastmilk EV-encapsulated lnRNAs in mother to child signaling.     

Protein Paucimannosylation Is an Enriched N‐Glycosylation Signature of Human Cancers

While aberrant protein glycosylation is a recognized characteristic of human cancers, advances in glycoanalytics continue to discover new associations between glycoproteins and tumorigenesis. This glycomics‐centric study investigates a possible link between protein paucimannosylation, an under‐studied class of human N‐glycosylation [Man_1‐3GlcNAc₂Fuc_0‐1], and cancer. The paucimannosidic glycans (PMGs) of 34 cancer cell lines and 133 tissue samples spanning 11 cancer types and matching non‐cancerous specimens are profiled from 467 published and unpublished PGC‐LC‐MS/MS N‐glycome datasets collected over a decade. PMGs, particularly Man_2‐3GlcNAc₂Fuc₁, are prominent features of 29 cancer cell lines, but the PMG level varies dramatically across and within the cancer types (1.0–50.2%). Analyses of paired (tumor/non‐tumor) and stage‐stratified tissues demonstrate that PMGs are significantly enriched in tumor tissues from several cancer types including liver cancer (p = 0.0033) and colorectal cancer (p = 0.0017) and is elevated as a result of prostate cancer and chronic lymphocytic leukaemia progression (p < 0.05). Surface expression of paucimannosidic epitopes is demonstrated on human glioblastoma cells using immunofluorescence while biosynthetic involvement of N‐acetyl‐β‐hexosaminidase is indicated by quantitative proteomics. This intriguing association between protein paucimannosylation and human cancers warrants further exploration to detail the biosynthesis, cellular location(s), protein carriers, and functions of paucimannosylation in tumorigenesis and metastasis.     

Killer toxin-like chitinases in filamentous fungi: Structure,regulation and potential roles in fungal biology

Fungal chitinases are hydrolytic enzymes responsible for degradation of chitin. Chitinases are involved in several aspects of fungal biology, including cell wall remodelling during hyphal growth, conidial germination, autolysis, mycoparasitism and nutrient acquisition. They are divided into three distinct phylogenetic groups; A, B and C. Chitinases from the C group show structural similarities with the killer toxin zymocin produced by the yeast Kluyveromyces lactis and it is speculated that they have a similar function in filamentous ascomycetes, by facilitating penetration of toxins into cells of competing individuals. Genome analyses show that certain fungal species with a mycoparasitic lifestyle contain high numbers of killer toxin-like chitinases, compared with specialized saprotrophs and plant pathogens. Recent developments within this research field have revealed considerable variation in the modular structure and regulation of killer toxin-like chitinases, suggesting more diverse roles than merely fungal-fungal interactions. In this review, we summarize the current knowledge about this intriguing class of chitinases, including their modular structure, evolution, gene regulation, and functional analyses in mycoparasitic as well as in saprotrophic species. We also propose important questions for future research.