Seasonal changes in water quality and Sargassum biomass in southwest Australia

Sargassum C. Agardh is one of the most diverse genera of marine macro-algae and commonly inhabits shallow tropical and sub-tropical waters. This study aimed to investigate the effect of seasonality and the associated water quality changes on the distribution, canopy cover, mean thallus length and the biomass of Sargassum beds around Point Peron, Shoalwater Islands Marine Park, Southwest Australia. Samples of Sargassum and seawater were collected every three months from summer 2012 to summer 2014 from four different reef zones. A combination of in situ observations and WorldView-2 satellite remote-sensing images were used to map the spatial distribution of Sargassum beds and other associated benthic habitats. The results demonstrated a strong seasonal variation in the environmental parameters, canopy cover, mean thallus length, and biomass of Sargassum, which were significantly (P < 0.05) influenced by the nutrient concentration (PO43-, NO3-, NH4+) and rainfall. However, no variation in any studied parameter was observed among the four reef zones. The highest Sargassum biomass peaks occurred between late spring and early summer (from September to January). The results provide essential information to guide effective conservation and management, as well as sustainable utilisation of this coastal marine renewable resource

Combined data analysis of fossil and living mammals: a Paleogene sister taxon of Placentalia and the antiquity of Marsupialia

The Cretaceous–Paleogene (KPg) boundary, one of Earth’s five major extinction events, occurred just before the appearance of Placentalia in the fossil record. The Gobi Desert, Mongolia and the Western Interior of North America have important fossil mammals occurring just before and after the KPg boundary (e.g. Prodiacodon, Deltatheridium) that have yet to be phylogenetically tested in a character-rich context with molecular data. We present here phylogenetic analyses of >6000 newly scored anatomical observations drawn from six untested fossils and added to the largest existing morphological matrix for mammals. These data are combined with sequence data from 27 nuclear genes. Results show the existence of a new eutherian sister clade to Placentalia, which we name and characterize. The extinct clade Leptictidae is part of this placental sister clade, indicating that the sister clade survived the KPg event to co-exist in ancient ecosystems during the Paleogene radiation of placentals. Analysing the Cretaceous metatherian Deltatheridium in this character-rich context reveals it is a member of Marsupialia, a finding that extends the minimum age of Marsupialia before the KPg boundary. Numerous shared-derived features from multiple anatomical systems support the assignment of Deltatheridium to Marsupialia. Computed tomography scans of exquisite new specimens better document the marsupial-like dental replacement pattern of Deltatheridium. The new placental sister clade has both Asian and North American species, and is ancestrally characterized by shared derived features such as a hind limb modified for saltatorial locomotion

Weekend effect: analysing temporal trends in solid organ donation

Background: Research suggests patients treated over weekends experience poorer outcomes. Only one US-based study explored this weekend effect in organ donation, specifically the kidney discard rate. In Australia potential donors are referred to a donation service, and donation proceeds if family consent is granted and the donor is deemed medically suitable to donate. Organ procurement occurs when utilization is almost certain hence discard rates are much lower than in the USA. We aimed to characterize the effect of weekend referral on organ donation in Australia. Methods: We retrospectively reviewed all New South Wales Organ and Tissue Donation Service logs from 2010 to 2016. Our primary outcome was progression to organ procurement, and secondary outcomes were family consent and meeting medical suitability thresholds. We used logistic regression with random effects adjusting for clustering of referral hospitals. Results: Of 3496 potential donors referred for consideration, 694 (20%) progressed to organ procurement. There were fewer referrals on weekends (average 415 versus 588 for weekdays). However, donation rates were no lower for weekend compared to weekday referrals (adjusted OR 1.17; 95% CI 0.95, 1.44). Family consent (adjusted OR 1.20; 95% CI 1.00, 1.44) and medical suitability (adjusted OR 1.15; 95% CI 0.96, 1.38) were not lower for weekend compared to weekday referrals. Similar results were found for all sensitivity analyses conducted. Conclusions: In Australia, the donation pathway operates consistently throughout the week, with donation no less likely to proceed on weekends and holidays. This finding contrasts with findings in the USA

Neogenin recruitment of the WAVE regulatory complex maintains adherens junction stability and tension

To maintain tissue integrity during epithelial morphogenesis, adherens junctions (AJs) must resist the mechanical stresses exerted by dynamic tissue movements. Junctional stability is dependent on actomyosin contractility within the actin ring. Here we describe a novel function for the axon guidance receptor, Neogenin, as a key component of the actin nucleation machinery governing junctional stability. Loss of Neogenin perturbs AJs and attenuates junctional tension. Neogenin promotes actin nucleation at AJs by recruiting the Wave regulatory complex (WRC) and Arp2/3. A direct interaction between the Neogenin WIRS domain and the WRC is crucial for the spatially restricted recruitment of the WRC to the junction. Thus, we provide the first example of a functional WIRS-WRC interaction in epithelia. We further show that Neogenin regulates cadherin recycling at the AJ. In summary, we identify Neogenin as a pivotal component of the AJ, where it influences both cadherin dynamics and junctional tension

Quadratic fermionic interactions yield effective Hamiltonians for adiabatic quantum computing

Polynomially-large ground-state energy gaps are rare in many-body quantum systems, but useful for adiabatic quantum computing. We show analytically that the gap is generically polynomially-large for quadratic fermionic Hamiltonians. We then prove that adiabatic quantum computing can realize the ground states of Hamiltonians with certain random interactions, as well as the ground states of one, two, and three-dimensional fermionic interaction lattices, in polynomial time. Finally, we use the Jordan-Wigner transformation and a related transformation for spin-3/2 particles to show that our results can be restated using spin operators in a surprisingly simple manner. A direct consequence is that the one-dimensional cluster state can be found in polynomial time using adiabatic quantum computing.Comment: 14 page

A Sensitive Homecage-Based Novel Object Recognition Task for Rodents

The recognition of novel objects is a common cognitive test for rodents, but current paradigms have limitations, such as low sensitivity, possible odor confounds and stress due to being performed outside of the homecage. We have developed a paradigm that takes place in the homecage and utilizes four stimuli per trial, to increase sensitivity. Odor confounds are eliminated because stimuli consist of inexpensive, machined wooden beads purchased in bulk, so each experimental animal has its own set of stimuli. This paradigm consists of three steps. In Step 1, the sampling phase, animals freely explore familiar objects (FO). Novel Objects (NO1 and NO2) are soiled with bedding from the homecage, to acquire odor cues identical to those of the FO. Steps 2 and 3 are test phases. Herein we report results of this paradigm from neurologically intact adult rats and mice of both sexes. Identical procedures were used for both species, except that the stimuli used for the mice were smaller. As expected in Step 2 (NO1 test phase), male and female rats and mice explored NO1 significantly more than FO. In Step 3 (NO2 test phase), rats of both sexes demonstrated a preference for NO2, while this was seen only in female mice. These results indicate robust novelty recognition during Steps 2 and 3 in rats. In mice, this was reliably seen only in Step 2, indicating that Step 3 was difficult for them under the given parameters. This paradigm provides flexibility in that length of the sampling phase, and the delay between test and sampling phases can be adjusted, to tailor task difficulty to the model being tested. In sum, this novel object recognition test is simple to perform, requires no expensive supplies or equipment, is conducted in the homecage (reducing stress), eliminates odor confounds, utilizes 4 stimuli to increase sensitivity, can be performed in both rats and mice, and is highly flexible, as sampling phase and the delay between steps can be adjusted to tailor task difficulty. Collectively, these results indicate that this paradigm can be used to quantify novel object recognition across sex and species

Hepatitis transmission risk IN kidney Transplantation (the HINT study); a cross-sectional survey of transplant clinicians in Australian and New Zealand

Background Interpreting hepatitis serology and virus transmission risk in transplantation can be challenging. Decisions must balance opportunity to transplant against potential infection transmission. We aimed to survey understanding among the Australian and New Zealand medical transplant workforce of hepatitis risk in kidney donors and recipients. Methods An anonymous, self-completed, cross-sectional survey was distributed via electronic mailing lists to Australian and New Zealand clinicians involved in kidney transplantation (2014-2015). We compared interpretation of clinical scenarios with paired donor and recipient hepatitis B virus and hepatitis C virus serology to recommendations in clinical practice guidelines. We used logistic regression modeling to investigate characteristics associated with decisions on transplant suitability in scenarios with poor (<50%) guideline concordance (odds ratios [OR]). Results One hundred ten respondents had representative workforce demographics: most were male (63%) nephrologists (74%) aged 40 to 49 years. Although donor and recipient hepatitis status was largely well understood, transplant suitability responses varied among respondents. For a hepatitis B virus surface antigen-positive donor and vaccinated recipient, 44% suggested this was unsuitable for transplant (guideline concordant) but 35% suggested this was suitable with prophylaxis (guideline divergent). In 4 scenarios with transplant suitability guideline concordance less than 50%, acute transplant care involvement predicted guideline concordant responses (OR, 1.69; P = 0.04). Guideline concordant responses were chosen less by hepatologists, intensive care doctors (OR, 0.23, 0.35, respectively; P = 0.01), and New Zealanders (guideline concordant responses OR, 0.17; P < 0.01; alternative responses OR, 4.31; P < 0.01). Conclusions Despite broadly consistent interpretations of hepatitis serology, transplant suitability decisions varied and often diverged from guidelines. Improved decision support may reduce clinician variability

HTS-Compatible Patient-Derived Cell-Based Assay to Identify Small Molecule Modulators of Aberrant Splicing in Myotonic Dystrophy Type 1

Myotonic dystrophy type 1 (DM1) is a genetic disorder characterized by muscle wasting, myotonia, cataracts, cardiac arrhythmia, hyperinsulinism and intellectual deficits, and is caused by expansion of a CTG repeat in the 3’UTR of the Dystrophia Myotonica-Protein Kinase (DMPK) gene. The DMPK transcripts containing expanded CUG repeats accumulate in nuclear foci and ultimately cause mis-splicing of secondary genes through the dysregulation of RNA-binding proteins including Muscleblind 1 (MBNL1) and CUG binding protein 1 (CUGBP1). Correction of mis-splicing of genes such as the Skeletal muscle-specific chloride channel 1 (CLCN1), Cardiac troponin T (TNNT2), Insulin receptor (INSR) and Sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 1 (SERCA1) may alleviate some of the symptoms of DM1; hence identification of small molecule modulators is an important step towards a therapy for DM1 patients. Here we describe the generation of immortalized myoblast cell lines derived from healthy (DMPK CTG5) and DM1 patient (DMPK CTG1000) fibroblasts by constitutive overexpression of human telomerase reverse transcriptase (hTERT) and inducible overexpression of the Myoblast determination factor (MYOD). MBNL1-containing nuclear foci, mis-splicing events and defective myotube differentiation defects characteristic of DM1 were observed in these cells. A CLCN1 luciferase minigene construct (CLCN1-luc) was stably introduced to monitor intron 2 retention in the DM1 cellular context (a reported splicing defect in DM1). The assay was validated by performing a high-throughput screen (HTS) of ~13,000 low molecular weight compounds against the CLCN1-luc DM1 myoblast cell line, providing an ideal system for conducting HTS to better understand and treat DM1

Heck Coupling of Olefins to Mixed Methyl/Thienyl Monolayers on Si(111) Surfaces

The Heck reaction has been used to couple olefins to a Si(111) surface that was functionalized with a mixed monolayer comprised of methyl and thienyl groups. The coupling method maintained a conjugated linkage between the surface and the olefinic surface functionality, to allow for facile charge transfer from the silicon surface. While a Si(111) surface terminated only with thienyl groups displayed a surface recombination velocity, S, of 670 ± 190 cm s^(–1), the mixed CH_3/SC_4H_3–Si(111) surfaces with a coverage of θ_(SC_4H_3) = 0.15 ± 0.02 displayed a substantially lower value of S = 27 ± 9 cm s^(–1). Accordingly, CH_3/SC_4H_3–Si(111) surfaces were brominated with N-bromosuccinimide, to produce mixed CH_3/SC_4H_2Br–Si(111) surfaces with coverages of θ_(Br–Si) < 0.05. The resulting aryl halide surfaces were activated using [Pd(PPh_3)_4] as a catalyst. After activation, Pd(II) was selectively coordinated by oxidative addition to the surface-bound aryl halide. The olefinic substrates 4-fluorostyrene, vinylferrocene, and protoporphyrin IX dimethyl ester were then coupled (in dimethylformamide at 100 °C) to the Pd-containing functionalized Si surfaces. The porphyrin-modified surface was then metalated with Co, Cu, or Zn. The vinylferrocene-modified Si(111) surface showed a linear dependence of the peak current on scan rate in cyclic voltammetry, indicating that facile electron transfer had been maintained and providing evidence of a robust linkage between the Si surface and the tethered ferrocene. The final Heck-coupled surface exhibited S = 70 cm s^(–1), indicating that high-quality surfaces could be produced by this multistep synthetic approach for tethering small molecules to silicon photoelectrodes