DSC study of sucrose melting

An early endothermic peak at approximately 150 degrees C was observed for crystalline sucrose by differential scanning calorimetry. The enthalpy at this temperature was found to vary with recrystallised sucrose from different sources. The addition of mineral salts to recrystallisation solutions decreased the enthalpy of the peak at around 150 degrees C, whereas the absence of salts increased it. The presence of organic solvents and polysaccharides in solution had a minor effect compared to the inorganic impurities. The peak was also depleted by increasing the amount of stirring and temperature at which recrystallisation was performed.     

The FLP-side of nematodes

The central role of FMRFamide-like peptides (FLPs) in nematode motor and sensory capabilities makes FLP signalling an appealing target for new parasiticides. Accumulating evidence has revealed an astounding level of FLP sequence conservation and diversity in the phylum Nematoda, and preliminary work has begun to identify the nematode FLP receptor complement in Caenorhabditis elegans, with a view to investigating their basic biology and therapeutic potential. However, much work is needed to clarify the functional aspects of FLP signalling and how these peptides exert their effects at the organismal level. Here, we summarize our current knowledge of nematode FLP signalling.     

HIV-1 Gag co-opts a cellular complex containing DDX6, a helicase that facilitates capsid assembly

To produce progeny virus, human immunodeficiency virus type I (HIV-1) Gag assembles into capsids that package the viral genome and bud from the infected cell. During assembly of immature capsids, Gag traffics through a pathway of assembly intermediates (AIs) that contain the cellular adenosine triphosphatase ABCE1 (ATP-binding cassette protein E1). In this paper, we showed by coimmunoprecipitation and immunoelectron microscopy (IEM) that these Gag-containing AIs also contain endogenous processing body (PB)-related proteins, including AGO2 and the ribonucleic acid (RNA) helicase DDX6. Moreover, we found a similar complex containing ABCE1 and PB proteins in uninfected cells. Additionally, knockdown and rescue studies demonstrated that the RNA helicase DDX6 acts enzymatically to facilitate capsid assembly independent of RNA packaging. Using IEM, we localized the defect in DDX6-depleted cells to Gag multimerization at the plasma membrane. We also confirmed that DDX6 depletion reduces production of infectious HIV-1 from primary human T cells. Thus, we propose that assembling HIV-1 co-opts a preexisting host complex containing cellular facilitators such as DDX6, which the virus uses to catalyze capsid assembly.     

Hen harrier Circus cyaneus nest sites on the Isle of Mull are associated with habitat mosaics and constrained by topography

Capsule: Hen Harriers Circus cyaneus on the Isle of Mull, UK, are associated with habitat mosaics consisting of moorland, scrub and forestry but avoid grazed land, suggesting that forested habitats could be managed sympathetically for the Hen Harrier in the future should the current UK population increase.

Aims: To use distribution modelling to investigate nesting habitat associations using a long-term data set for the Hen Harrier on Mull.

Methods: We develop area-interaction models using a least absolute shrinkage and selection operator penalty to explore the distribution of 102 Hen Harrier nest sites in relation to habitat and topography. Our model is then successfully validated in tests using data for 70 nest sites from subsequent years.

Results: Our model is effective in predicting suitable areas for Hen Harrier nest sites and indicates that Hen Harriers on Mull are found in habitat mosaics below 200 m above sea level. Hen Harrier nest intensity is positively associated with increasing proportions of moorland and scrub, open canopy forestry and closed canopy forestry. Nest intensity is negatively associated with increasing proportions of grazed land.

Conclusion: Hen Harriers avoid grazed areas but are relatively tolerant of other habitat combinations. These findings are supported by previous observations of Hen Harrier habitat use and have implications for the recovery of some Hen Harrier populations in Special Protection Areas and future forest management. Open canopy forest and forest mosaics could potentially be incorporated into landscape-scale conservation plans for Hen Harriers using the population on Mull as an example.     

Proteomic Analysis of Adult Ascaris suum Fluid Compartments and Secretory Products

Background

Strategies employed by parasites to establish infections are poorly understood. The host-parasite interface is maintained through a molecular dialog that, among other roles, protects parasites from host immune responses. Parasite excretory/secretory products (ESP) play major roles in this process. Understanding the biology of protein secretion by parasites and their associated functional processes will enhance our understanding of the roles of ESP in host-parasite interactions.

Methodology/Principal Findings

ESP was collected after culturing 10 adult female Ascaris suum. Perienteric fluid (PE) and uterine fluid (UF) were collected directly from adult females by dissection. Using SDS-PAGE coupled with LC-MS/MS, we identified 175, 308 and 274 proteins in ESP, PE and UF, respectively. Although many proteins were shared among the samples, the protein composition of ESP was distinct from PE and UF, whereas PE and UF were highly similar. The distribution of gene ontology (GO) terms for proteins in ESP, PE and UF supports this claim. Comparison of ESP composition in A. suum, Brugia malayi and Heligmosoides polygyrus showed that proteins found in UF were also secreted by males and by larval stages of other species, suggesting that multiple routes of secretion may be used for homologous proteins. ESP composition of nematodes is both phylogeny- and niche-dependent.

Conclusions/Significance

Analysis of the protein composition of A. suum ESP and UF leads to the conclusion that the excretory-secretory apparatus and uterus are separate routes for protein release. Proteins detected in ESP have distinct patterns of biological functions compared to those in UF. PE is likely to serve as the source of the majority of proteins in UF. This analysis expands our knowledge of the biology of protein secretion from nematodes and will inform new studies on the function of secreted proteins in the orchestration of host-parasite interactions.     

Maternal cardiovascular disease after twin pregnancies complicated by hypertensive disorders of pregnancy: a population-based cohort study

Background:People whose singleton pregnancy is affected by hypertensive disorders of pregnancy (HDP) are at risk of future cardiovascular disease. It is unclear, however, whether this association can be extrapolated to twin pregnancies. We aimed to compare the association between HDP and future cardiovascular disease after twin and singleton pregnancies.Methods:We conducted a population-based retrospective cohort study that included nulliparous people in Ontario, Canada, 1992–2017. We compared the future risk of cardiovascular disease among pregnant people from the following 4 groups: those who delivered a singleton without HDP (referent) and with HDP, and those who delivered twins either with or without HDP.Results:The populations of the 4 groups were as follows: 1 431 651 pregnant people in the singleton birth without HDP group; 98 631 singleton birth with HDP; 21 046 twin birth without HDP; and 4283 twin birth with HDP. The median duration of follow-up was 13 (interquartile range 7–20) years. The incidence rate of cardiovascular disease was lowest among those with a singleton or twin birth without HDP (0.72 and 0.74 per 1000 person-years, respectively). Compared with people with a singleton birth without HDP, the risk of cardiovascular disease was highest among those with a singleton birth and HDP (1.47 per 1000 person-years; adjusted hazard ratio [HR] 1.81 [95% confidence interval (CI) 1.72–1.90]), followed by people with a twin pregnancy and HDP (1.07 per 1000 person-years; adjusted HR 1.36 [95% CI 1.04–1.77]). The risk of the primary outcome after a twin pregnancy with HDP was lower than that after a singleton pregnancy with HDP (adjusted HR 0.74 [95% CI 0.57–0.97]), when compared directly.Interpretation:In a twin pregnancy, HDP are weaker risk factors for postpartum cardiovascular disease than in a singleton pregnancy.

Cardiovascular disease has been shown to be the leading cause of death among women.^1–3 Classic risk factors for cardiovascular disease include obesity, diabetes mellitus, hypertension and family history of cardiovascular disease. ³ More recently, an association has been established between a history of hypertensive disorders of pregnancy (HDP) — gestational hypertension and pre-eclampsia — and future risk of cardiovascular disease.^1,4–11 Consequently, some recommend using a history of HDP for cardiovascular disease risk stratification in women.^3,12The leading hypothesis for the pathogenesis of HDP is that it results from abnormal placentation due to impaired trophoblast invasion,^13–16 resulting in reduced placental perfusion.^17–19 This, in turn, leads to abnormal secretion of the angiogenic factors soluble FMS-like tyrosine kinase 1 (sFlt1) and soluble endoglin (sEng),²⁰ which induce endothelial dysfunction and the clinical manifestations of HDP.^19,21–24 The mechanisms underlying the association between HDP and future cardiovascular disease are under debate.²⁵ One hypothesis is that HDP are merely a marker of underlying subclinical or clinical vascular risk factors that predispose a person to both HDP and future cardiovascular disease.A person who is pregnant with twins is at about 3–4 times higher risk of HDP than a person with a singleton pregnancy,^26–33 with rates of 14% and 5%, respectively.³⁴ The higher risk of HDP in twin pregnancies may be due to higher circulating sFlt1 and sEng owing to greater placental mass in twin pregnancies, ^35–37 and less related to the classic vascular risk factors for HDP in a singleton pregnancy. Therefore, a logical question is whether the established higher risk of future cardiovascular disease after singleton pregnancies with HDP also occurs in twin pregnancies with HDP. Limited data are available to answer this question.³⁸ In the current study, we aimed to test the hypothesis that the association between HDP and future cardiovascular disease is less pronounced in twin versus singleton pregnancies.     

The Paleobiosphere: a novel device for the in vivo testing of hydrocarbon producing-utilizing microorganisms

The construction and testing of a unique instrument, the Paleobiosphere, which mimics some of the conditions of the ancient earth, is described. The instrument provides an experimental testing system for determining if certain microbes, when provided an adequate environment, can degrade biological materials to produce fuel-like hydrocarbons in a relatively short time frame that become trapped by the shale. The conditions selected for testing included a particulate Montana shale (serving as the “Trap Shale”), plant materials (leaves and stems of three extant species whose origins are in the late Cretaceous), a water-circulating system, sterile air, and a specially designed Carbotrap through which all air was passed as exhaust and volatile were hydrocarbons trapped. The fungus for initial testing was Annulohypoxylon sp., isolated as an endophyte of Citrus aurantifolia. It produces, in solid and liquid media, a series of hydrocarbon-like molecules. Some of these including 1,8-cineole, 2-butanone, propanoic acid, 2-methyl-, methyl ester, benzene (1-methylethyl)-, phenylethyl alcohol, benzophenone and azulene, 1,2,3,5,6,7,8,8a-octahydro-1,4-dimethyl-7-(1-methylethenyl), [1S-(1α,7α,8aβ)]. These were the key signature compounds used in an initial Paleobiosphere test. After 3 weeks, incubation, the volatiles associated with the harvested “Trap Shale” included each of the signature substances as well as other fungal-associated products: some indanes, benzene derivatives, some cyclohexanes, 3-octanone, naphthalenes and others. The fungus thus produced a series of “Trap Shale” products that were representative of each of the major classes of hydrocarbons in diesel fuel (Mycodiesel). Initial tests with the Paleobiosphere offer some evidence for a possible origin of hydrocarbons trapped in bentonite shale. Thus, with modifications, numerous other tests can also be designed for utilization in the Paleobiosphere.     

Improved islet survival and in vitro function using solubilized small intestinal submucosa

In vitro proliferation of isolated pancreaticislets has become an area of great interest given the scarcity of clinicalisletdonors and the islet mass requirements for clinical islet transplantation.Smallintestinal submucosa (SIS), a naturally occurring extracellular matrix, hasbeeninvestigated to promote wound healing, tissue remodeling and cell growth. Thisstudy evaluated recovery and function of isolated canine pancreatic isletsfollowing in vitro tissue culture. Pancreatic islets wereisolated from mongrel dogs using standard surgical procurement followed byintraductal collagenase distension, mechanical dissociation and EuroFicollpurification. Groups of purified islets were cultured in a humidifiedatmosphereof 95% air and 5% CO₂ for 48 hours in standard islet cultureconditions of CMRL 1066 tissue culture media (Gibco) which had beensupplementedwith 25M HEPES, penicillin/streptomycin and either 10% heat inactivatedfetal calf serum (FCS, Gibco) or solubilized SIS solution (Cook Biotech, Inc.,West Lafayette, IN). The mean recovery of islets following the culture periodwas determined by sizing duplicate counts of a known volume and viability wasassessed by static incubation with low glucose (2.8 mM), highglucose (20 mM) and high glucose solution supplemented with 50m IBMX solution. Remaining islets were embeddedhistologically.From a consecutive series of six culture experiments, a significantly higher (p< 0.05) recovery of islets co-cultured with SIS was observed when comparedtocontrols. Mean islet recovery was 84.5 ± 2.9% (mean ± SEM) fromthe SIS cultured group compared with 64.7 ± 4.5% from the control groupcultured in FCS (p < 0.05, n=6). Islets from the SIS treated group exhibiteda significantly higher (p <, 0.05) insulin response to the high glucosestimulus than islets cultured in the standard FCS cultured solution. Thecalculated stimulation index was 12.3 ± 3.4 for the SIS-treated groupcompared with 5.6 ± 1.8 for the standard cultured group (p < 0.05).The overall mean numbers of islets recovered following invitro culture was also higher in the SIS-treated group. Theproportion of islets with a mean diameter >150 m increasedfrom 24% to 31% in the SIS-treated group, whereas the same proportion decreasedto 18% from 22% in the control (FCS-treated) group. Histological evaluation offixed tissue samples collected following the culture period identified insulinand glucagon-secreting cells in the SIS and FCS treated groups, however ahigherfrequency of insulin positive cells were detected consistently in the SIStreated group. A proliferation marker (PCNA) identified positive cells withinboth groups as well. This study suggests that co-culture of freshly isolatedcanine islets in medium supplemented with solubilized SIS can improve thepost-culture recovery and in vitro islet function. Futureinvestigations will focus on the cellular interactions of SIS, bothinvitro and in vivo.