Plasmid analysis of Australian strains of Salmonella enteritidis

Using an in-well lysis technique, 73 Australian strains of Salmonella enteritidis were shown to possess a large plasmid, similar in size to that possessed by a reference phage type 4 strain. Restriction analysis of the large plasmid from nine strains using EcoRI, HindIII and PstI suggested that these plasmids are similar to or the same as the 38 MDa plasmid described in strains of this species from other parts of the world.     

Trends in tuna carbon isotopes suggest global changes in pelagic phytoplankton communities

Considerable uncertainty remains over how increasing atmospheric CO₂ and anthropogenic climate changes are affecting open‐ocean marine ecosystems from phytoplankton to top predators. Biological time series data are thus urgently needed for the world's oceans. Here, we use the carbon stable isotope composition of tuna to provide a first insight into the existence of global trends in complex ecosystem dynamics and changes in the oceanic carbon cycle. From 2000 to 2015, considerable declines in δ¹³C values of 0.8‰–2.5‰ were observed across three tuna species sampled globally, with more substantial changes in the Pacific Ocean compared to the Atlantic and Indian Oceans. Tuna recorded not only the Suess effect, that is, fossil fuel‐derived and isotopically light carbon being incorporated into marine ecosystems, but also recorded profound changes at the base of marine food webs. We suggest a global shift in phytoplankton community structure, for example, a reduction in ¹³C‐rich phytoplankton such as diatoms, and/or a change in phytoplankton physiology during this period, although this does not rule out other concomitant changes at higher levels in the food webs. Our study establishes tuna δ¹³C values as a candidate essential ocean variable to assess complex ecosystem responses to climate change at regional to global scales and over decadal timescales. Finally, this time series will be invaluable in calibrating and validating global earth system models to project changes in marine biota.     

Expansion of GARP-Expressing CD4+CD25−FoxP3+ T Cells and SATB1 Association with Activation and Coagulation in Immune Compromised HIV-1-Infected Individuals in South Africa

Virologica Sinica - Although antiretroviral treatment lowers the burden of human immunodeficiency virus (HIV)-related disease, it does not always result in immunological recovery. This manifests as...     

Functional activity of RLIM/Rnf12 is regulated by phosphorylation-dependent nucleocytoplasmic shuttling

The X-linked gene Rnf12 encodes the ubiquitin ligase really interesting new gene (RING) finger LIM domain–interacting protein (RLIM)/RING finger protein 12 (Rnf12), which serves as a major sex-specific epigenetic regulator of female mouse nurturing tissues. Early during embryogenesis, RLIM/Rnf12 expressed from the maternal allele is crucial for the development of extraembryonic trophoblast cells. In contrast, in mammary glands of pregnant and lactating adult females RLIM/Rnf12 expressed from the paternal allele functions as a critical survival factor for milk-producing alveolar cells. Although RLIM/Rnf12 is detected mostly in the nucleus, little is known about how and in which cellular compartment(s) RLIM/Rnf12 mediates its biological functions. Here we demonstrate that RLIM/Rnf12 protein shuttles between nucleus and cytoplasm and this is regulated by phosphorylation of serine S214 located within its nuclear localization sequence. We show that shuttling is important for RLIM to exert its biological functions, as alveolar cell survival activity is inhibited in cells expressing shuttling-deficient nuclear or cytoplasmic RLIM/Rnf12. Thus regulated nucleocytoplasmic shuttling of RLIM/Rnf12 coordinates cellular compartments during mammary alveolar cell survival.     

Defining the Range of Pathogens Susceptible to Ifitm3 Restriction Using a Knockout Mouse Model

The interferon-inducible transmembrane (IFITM) family of proteins has been shown to restrict a broad range of viruses in vitro and in vivo by halting progress through the late endosomal pathway. Further, single nucleotide polymorphisms (SNPs) in its sequence have been linked with risk of developing severe influenza virus infections in humans. The number of viruses restricted by this host protein has continued to grow since it was first demonstrated as playing an antiviral role; all of which enter cells via the endosomal pathway. We therefore sought to test the limits of antimicrobial restriction by Ifitm3 using a knockout mouse model. We showed that Ifitm3 does not impact on the restriction or pathogenesis of bacterial (Salmonella typhimurium, Citrobacter rodentium, Mycobacterium tuberculosis) or protozoan (Plasmodium berghei) pathogens, despite in vitro evidence. However, Ifitm3 is capable of restricting respiratory syncytial virus (RSV) in vivo either through directly restricting RSV cell infection, or by exerting a previously uncharacterised function controlling disease pathogenesis. This represents the first demonstration of a virus that enters directly through the plasma membrane, without the need for the endosomal pathway, being restricted by the IFITM family; therefore further defining the role of these antiviral proteins.     

The Responses of Young Domestic Horses to Human-Given Cues

It has been suggested that the process of domestication, at least in some species, has led to an innate predisposition to be skilled at reading human communicative and attentional cues. Adult domestic horses (Equus caballus) are highly sensitive to subtle bodily cues when determining if a person is attending to them but they are less adept at using human communicative cues in object choice tasks. Here we provide the first study into the ontogeny of such skills in order to gain insights into the mechanisms underlying these abilities. Compared with adult horses, youngsters under the age of three could use body orientation but not more subtle cues such as head movement and open/closed eyes to correctly choose an attentive person to approach for food. Across two object choice experiments, the performance of young horses was comparable to that of adult horses – subjects were able to correctly choose a rewarded bucket using marker placement, pointing and touching cues but could not use body orientation, gaze, elbow pointing or tapping cues. Taken together these results do not support the theory that horses possess an innate predisposition to be particularly skilled at using human cues. Horses'' ability to determine whether humans are attending to them using subtle body cues appears to require significant experience to fully develop and their perhaps less remarkable use of limited cues in object choice tasks, although present at a much earlier age, is likely to reflect a more general learning ability related to stimulus enhancement rather than a specific ‘human-reading’ skill.     

Rab5 regulates internalisation of P2X4 receptors and potentiation by ivermectin

The P2X4 receptor is an ATP-gated ion channel expressed in neurons, endothelia and immune cells. Plasma membrane expression of P2X4 is regulated by dynamin-dependent endocytosis, and this study identifies a Rab5-dependent pathway of receptor internalisation. Expression of Rab5 constructs altered the distribution of P2X4 in HEK-293 cells, and both constitutive internalisation and agonist-induced desensitisation of P2X4 were increased by co-expression of wild-type Rab5 or constitutively active Rab5 (Q79L). Expression of inactive dynamin K44A and Rab5 S34N constructs abolished agonist-induced desensitisation, suggesting internalisation as the underlying mechanism. Blocking P2X4 internalisation in this way also abolished potentiation of ATP-induced currents by the allosteric modulator ivermectin. This suggests that the dynamin-Rab5 internalisation pathway is essential for the ivermectin potentiation effect. In agreement with this hypothesis, the co-expression of wild-type dynamin, wild-type Rab5 or active Rab5 (Q79L) could increase the potentiation of the ATP-induced P2X4 response by ivermectin. These findings highlight Rab5 GTPase as a key regulator of P2X4 receptor cell surface expression and internalisation.     

Separate and overlapping relationships of inattention and hyperactivity/impulsivity in children and adolescents with attention-deficit/hyperactivity disorder

There is debate regarding the dimensional versus categorical nature of attention-deficit/hyperactivity disorder (ADHD). This study utilized confirmatory factor analysis to examine this issue. ADHD symptoms rated on interviews and rating scales from a large sample of individuals (ages 3–17, 74 % male, 75 % Caucasian) with ADHD were examined (n = 242). Four potential factor structures were tested to replicate prior findings in a sample with a wide age range and included only participants who met DSM-IV-TR diagnostic criteria for ADHD. Correlations with executive function measures were performed to further assess the separability and validity of the derived factors. The data support a bifactor model with a general ADHD factor and two specific factors, inattention and hyperactivity/impulsivity. Importantly, the individual factors were also differentially correlated with executive functioning measures. This study adds to a growing literature suggesting both a general component to ADHD, as well as dimensional traits of inattention and hyperactivity/impulsivity, associated with distinct executive functioning profiles. The presence of a general underlying factor contraindicates separating the inattentive and combined subtypes of ADHD into distinct disorders.