Fish predation on sea urchins on the Great Barrier Reef

Predators are important for regulating adult sea urchin densities. Here, we employ remote underwater video cameras to record diurnal predation on tethered sea urchins at Lizard Island on the Great Barrier Reef (GBR). We identified four fish predators of adult sea urchins (Balistoides viridescens, Balistapus undulatus, Lethrinus atkinsoni and Choerodon schoenleinii). Predator activity appeared to be site-specific. Balistoides viridescens and B. undulatus (f: Balistidae) were the two most important predators of Echinometra mathaei with the former handling E. mathaei significantly faster (mean 0.7?min) than B. undulatus (5.2?min). Balistoides viridescens also successfully preyed on 70?% of detections, while C. schoenleinii, B. undulatus and L. atkinsoni preyed on just 33, 17 and <1?%, respectively. Additionally, B. viridescens were behaviourally dominant among predator species and were observed as aggressors in 30 encounters with B. undulatus and 8 encounters with L. atkinsoni. In only one encounter was B. viridescens the recipient of any aggression (from B. undulatus). In terms of relative vulnerability, of the three sea urchin species examined, E. mathaei were more vulnerable to predation than Diadema setosum or Echinothrix calamaris, with mean handling times of 1.2, 4.8 and 10.3?min, respectively. Balistoides viridescens and B. undulatus both appear to be able to play an important role as predators of sea urchins on the relatively intact coral reefs of Lizard Island. However, B. viridescens emerge as the most efficient predator in terms of handling speed and the proportion of detections preyed upon. They were also the behaviourally dominant predator. This preliminary study of the predators of sea urchins on the GBR highlights the potential significance of relatively scarce but functionally important species.     

Synthesis and antioxidant properties of dendritic polyphenols

Three dendritic polyphenols (generation 1) were synthesized: a syringaldehyde-based dendrimer (1), a vanillin-based dendrimer (2), and an iodinated vanillin-based dendrimer (3). They all showed strong antioxidant activity according to the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical assay. The syringaldehyde dendrimer was twice and 10 times stronger than quercetin and Trolox, respectively. The vanillin-based dendrimer and its more hydrophobic iodinated derivative were also more potent antioxidants than quercetin and Trolox. The DPPH order of potency was 1 > 2, 3 > quercetin > Trolox. All three dendrimers also protected human LDL from free radical attack in a dose-dependent manner. Their order of free radical scavenging was 1 > 3 > 2 > quercetin > Trolox. The increased hydrophobic nature of the iodinated derivative may have contributed to its better LDL protection than 2. Protection of linoleic acid oxidation was studied by the β-carotene–linoleate assay. Dendrimer 1 was clearly superior to the other antioxidants in protecting the fatty acid. In case of DNA protection against free radical damage, the order of activity was 1 > quercetin > 2 > 3, Trolox. Pro-oxidant effect on copper-induced DNA oxidation showed the following order: quercetin, Trolox > 1 > 2 > 3. Results of the study show that dendritic antioxidants, even at the generation 1 level, provide promising antioxidant properties for their potential use as drug candidates for diseases associated with oxidative stress.     

Differential effects of circadian typology on sleep-related symptoms,physical fatigue and psychological well-being in relation to resilience

Various physiological and psychological functions are influenced by circadian typology (CT), which was reported to be related to resilience. However, few studies have assessed the effects of CT in relation to resilience. The aim of the present study was to assess the influence of CT on sleep-related symptoms, physical fatigue and psychological well-being in relation to resilience. The present study included a total of 1794 healthy hospital employees, and they completed the Morningness–Eveningness Questionnaire, Connor–Davidson Resilience Scale, Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, Fatigue Severity Scale, Hospital Anxiety and Depression Scale and World Health Organization Quality of Life Scale Abbreviated Version. Subjects with evening type showed lower sleep quality, more daytime sleepiness and physical fatigue than neither types and morning types. Additionally, evening types were more depressed and anxious and reported a poorer quality of life. CT was found to be a significant predictor of sleep quality, but CT was minimally associated with physical fatigue and psychological well-being in the regression analysis. Instead, resilience was substantially related to all of the variables measured. In conclusion, CT independently predicts sleep quality, but the effects of CT on physical fatigue and psychological well-being are negligible compared to those of resilience.     

HLA-DR typing using DNA amplification by the polymerase chain reaction and sequential hybridization to sequence-specific oligonucleotide probes

A series of sequence-specific oligonucleotides (SSOs) have been used to type alleles at the HLA-DRB1 locus. Genomic DNA was amplified to high copy number by the polymerase chain reaction (PCR) and hybridizations of the dot-blotted, amplified DNA to a series of 14 SSOs enabled the identification of the major specificities DR1-DRw14. Certain alleles (DR3 and DR4) could be rapidly and accurately identified by running the products of allele-specific amplification of genomic DNA on agarose gels. This approach facilitated the typing of serological specificities such as subtypes of DR3 (DRw17 and DRw18) as well as alleles previously detected by the mixed lymphocyte reaction including subtypes of DR4 (Dw4, Dw10, Dw13, Dw14, and Dw15). The HLA-DR types obtained by SSO probing conformed to rules of Mendelian inheritance when they were applied to a series of 75 families. A full DR type could be obtained from many individuals simultaneously without needing to separate or store viable lymphocytes. Thus, this technique may have considerable implications for the analysis of disease associations with HLA class II alleles, particularly in circumstances where facilities for the initial preparation and storage of the samples may be limited.     

Heterogeneity of Regional Brain Atrophy Patterns Associated with Distinct Progression Rates in Alzheimer’s Disease

We aimed to identify and characterize subtypes of Alzheimer’s disease (AD) exhibiting different patterns of regional brain atrophy on MRI using age- and gender-specific norms of regional brain volumes. AD subjects included in the Alzheimer''s Disease Neuroimaging Initiative study were classified into subtypes based on standardized values (Z-scores) of hippocampal and regional cortical volumes on MRI with reference to age- and gender-specific norms obtained from 222 cognitively normal (CN) subjects. Baseline and longitudinal changes of clinical characteristics over 2 years were compared across subtypes. Whole-brain-level gray matter (GM) atrophy pattern using voxel-based morphometry (VBM) and cerebrospinal fluid (CSF) biomarkers of the subtypes were also investigated. Of 163 AD subjects, 58.9% were classified as the “both impaired” subtype with the typical hippocampal and cortical atrophy pattern, whereas 41.1% were classified as the subtypes with atypical atrophy patterns: “hippocampal atrophy only” (19.0%), “cortical atrophy only” (11.7%), and “both spared” (10.4%). Voxel-based morphometric analysis demonstrated whole-brain-level differences in overall GM atrophy across the subtypes. These subtypes showed different progression rates over 2 years; and all subtypes had significantly lower CSF amyloid-β_1–42 levels compared to CN. In conclusion, we identified four AD subtypes exhibiting heterogeneous atrophy patterns on MRI with different progression rates after controlling the effects of aging and gender on atrophy with normative information. CSF biomarker analysis suggests the presence of Aβ neuropathology irrespective of subtypes. Such heterogeneity of MRI-based neuronal injury biomarker and related heterogeneous progression patterns should be considered in clinical trials and practice with AD patients.     

The Binaural Masking-Level Difference of Mandarin Tone Detection and the Binaural Intelligibility-Level Difference of Mandarin Tone Recognition in the Presence of Speech-Spectrum Noise

Binaural hearing involves using information relating to the differences between the signals that arrive at the two ears, and it can make it easier to detect and recognize signals in a noisy environment. This phenomenon of binaural hearing is quantified in laboratory studies as the binaural masking-level difference (BMLD). Mandarin is one of the most commonly used languages, but there are no publication values of BMLD or BILD based on Mandarin tones. Therefore, this study investigated the BMLD and BILD of Mandarin tones. The BMLDs of Mandarin tone detection were measured based on the detection threshold differences for the four tones of the voiced vowels /i/ (i.e., /i1/, /i2/, /i3/, and /i4/) and /u/ (i.e., /u1/, /u2/, /u3/, and /u4/) in the presence of speech-spectrum noise when presented interaurally in phase (S₀N₀) and interaurally in antiphase (S_πN₀). The BILDs of Mandarin tone recognition in speech-spectrum noise were determined as the differences in the target-to-masker ratio (TMR) required for 50% correct tone recognitions between the S₀N₀ and S_πN₀ conditions. The detection thresholds for the four tones of /i/ and /u/ differed significantly (p<0.001) between the S₀N₀ and S_πN₀ conditions. The average detection thresholds of Mandarin tones were all lower in the S_πN₀ condition than in the S₀N₀ condition, and the BMLDs ranged from 7.3 to 11.5 dB. The TMR for 50% correct Mandarin tone recognitions differed significantly (p<0.001) between the S₀N₀ and S_πN₀ conditions, at –13.4 and –18.0 dB, respectively, with a mean BILD of 4.6 dB. The study showed that the thresholds of Mandarin tone detection and recognition in the presence of speech-spectrum noise are improved when phase inversion is applied to the target speech. The average BILDs of Mandarin tones are smaller than the average BMLDs of Mandarin tones.