A Combination of CD28 (rs1980422) and IRF5 (rs10488631) Polymorphisms Is Associated with Seropositivity in Rheumatoid Arthritis: A Case Control Study

IntroductionThe aim of the study was to analyse genetic architecture of RA by utilizing multiparametric statistical methods such as linear discriminant analysis (LDA) and redundancy analysis (RDA).MethodsA total of 1393 volunteers, 499 patients with RA and 894 healthy controls were included in the study. The presence of shared epitope (SE) in HLA-DRB1 and 11 SNPs (PTPN22 C/T (rs2476601), STAT4 G/T (rs7574865), CTLA4 A/G (rs3087243), TRAF1/C5 A/G (rs3761847), IRF5 T/C (rs10488631), TNFAIP3 C/T (rs5029937), AFF3 A/T (rs11676922), PADI4 C/T (rs2240340), CD28 T/C (rs1980422), CSK G/A (rs34933034) and FCGR3A A/C (rs396991), rheumatoid factor (RF), anti–citrullinated protein antibodies (ACPA) and clinical status was analysed using the LDA and RDA.ResultsHLA-DRB1, PTPN22, STAT4, IRF5 and PADI4 significantly discriminated between RA patients and healthy controls in LDA. The correlation between RA diagnosis and the explanatory variables in the model was 0.328 (Trace = 0.107; F = 13.715; P = 0.0002). The risk variants of IRF5 and CD28 genes were found to be common determinants for seropositivity in RDA, while positivity of RF alone was associated with the CTLA4 risk variant in heterozygous form. The correlation between serologic status and genetic determinants on the 1st ordinal axis was 0.468, and 0.145 on the 2nd one (Trace = 0.179; F = 6.135; P = 0.001). The risk alleles in AFF3 gene together with the presence of ACPA were associated with higher clinical severity of RA.ConclusionsThe association among multiple risk variants related to T cell receptor signalling with seropositivity may play an important role in distinct clinical phenotypes of RA. Our study demonstrates that multiparametric analyses represent a powerful tool for investigation of mutual relationships of potential risk factors in complex diseases such as RA.     

SH3‐class Ras guanine nucleotide exchange factors are essential for Aspergillus fumigatus invasive growth

Proper hyphal morphogenesis is essential for the establishment and progression of invasive disease caused by filamentous fungi. In the human pathogen Aspergillus fumigatus, signalling cascades driven by Ras and Ras‐like proteins orchestrate a wide variety of cellular processes required for hyphal growth. For activation, these proteins require interactions with Ras‐subfamily‐specific guanine nucleotide exchange factors (RasGEFs). Although Ras‐protein networks are essential for virulence in all pathogenic fungi, the importance of RasGEF proteins is largely unexplored. A. fumigatus encodes four putative RasGEFs that represent three separate classes of RasGEF proteins (SH3‐, Ras guanyl nucleotide‐releasing protein [RasGRP]–, and LTE‐class), each with fungus‐specific attributes. Here, we show that the SH3‐class and RasGRP‐class RasGEFs are required for properly timed polarity establishment during early growth and branch emergence as well as for cell wall stability. Further, we show that SH3‐class RasGEF activity is essential for polarity establishment and maintenance, a phenotype that is, at least, partially independent of the major A. fumigatus Ras proteins, RasA and RasB. Finally, loss of both SH3‐class RasGEFs resulted in avirulence in multiple models of invasive aspergillosis. Together, our findings suggest that RasGEF activity is essential for the integration of multiple signalling networks to drive invasive growth in A. fumigatus.     

Assemblage structure,vertical distributions and stable-isotope compositions of anguilliform leptocephali in the Gulf of Mexico

In August 2007, October 2008 and September–October 2010, 241 Tucker trawl and plankton net tows were conducted at the surface to depths of 1377 m at six locations in the northern and eastern Gulf of Mexico (GOM) to document leptocephalus diversity and determine how assemblage structure, larval size, abundance and isotopic signatures differ across the region and with depth. Overall, 2696 leptocephali representing 59 distinct taxa from 10 families were collected. Five families accounted for 96% of the total catch with Congridae and Ophichthidae being the most abundant. The top four most abundant species composed 59% of the total catch and included: Ariosoma balearicum, Paraconger caudilimbatus, Rhynchoconger flavus and Ophichthus gomesii. Four anguilliform species not previously documented in the GOM as adults or leptocephali were collected in this study, including Monopenchelys acuta, Quassiremus ascensionis, Saurenchelys stylura and one leptocephalus only known from its larval stage, Leptocephalus proboscideus. Leptocephalus catches were significantly greater at night than during the day. Catches at night were concentrated in the upper 200 m of the water column and significantly declined with increasing depth. Leptocephali abundances and assemblages were significantly different between sites on the upper continental slope (c. 500 m depth) and sites on the middle to lower continental slope (c. 1500–2300 m). Sites on the lower continental slope had a mixture of deep-sea demersal, bathypelagic and coastal species, whereas upper-slope sites contained several numerically dominant species (e.g., A. balearicum, P. caudilimbatus) that probably spawn over the continental shelf and upper slope of the GOM. Standard lengths of the four dominant species differed between sites and years, indicating heterochronic reproduction and potential larval source pools within and outside of the GOM. Stable-isotope analyses (δ¹³C and δ¹⁵N) conducted on 185 specimens from six families revealed that leptocephali had a wide range of isotopic values at the family and size-class levels. Species in the families Muraenidae, Congridae and Ophichthidae had similar δ¹⁵N values compared with the broad range of δ¹⁵N values seen in the deep-sea families Nemichthyidae, Nettastomatidae and Synaphobranchidae. Stable-isotope values were variably related to length, with δ¹⁵N values being positively size correlated in ophichthids and δ¹³C values being negatively size correlated in A. balearicum and P. caudilimbatus. Results suggest that leptocephali feed in various water depths and masses, and on different components of POM, which could lead to niche partitioning. Ecological aspects of these important members of the plankton community provide insight into larval connectivity in the GOM as well as the early life history of Anguilliformes.     

Sperm protein (sp50) binds to acromosome and plasma membranes in a Ca2+-dependent manner: Possible role in acrosome reaction

Annexins are a family of Ca²⁺-binding proteins involved in the exocytotic process. The presence and the role of annexins in mammalian spermatozoa have not been well established. Two annexin-like proteins were obtained from guinea pig testis, a doublet of Mr 31–33 kD (p31/33) and a protein of Mr 50 kD (p50). Both proteins were able to bind to erythrocyte ghosts in a Ca²⁺-dependent fashion. Polyclonal antibodies against p31/33 reacted with two major proteins, Mrs 50 kD (sp50) and 42 kD (sp42), from mature and immature guinea pig spermatozoa. p50 and sp50 are likely the native proteins from testis and spermatozoa, respectively, and they are seemingly related. By immunofluorescence, sp50 was only found in the apical acrosome region of immature and capacitated and noncapacitated spermatozoa, and its location was intracellular. In spermatozoa undergoing acrosome reaction, sp50 was detected in the whole acrosome, while in spermatozoa that had undergone acrosome reaction sp50 was not detected. However, in the protein pattern of acrosome reaction vesicles, anti-p31/33 antibody revealed diffuse bands of Mr 35–38 kD. sp50 was able to bind to plasma membrane fragments and acrosome outer membrane from demembranated sperm in a Ca²⁺-dependent fashion. The presence of sp50 in the acrosome region, its distribution throughout the acrosome membrane just before the acrosome reaction, and its ability to bind both plasma and outer acrosome membranes in a Ca²⁺-dependent manner suggest that sp50 may participate in the acrosome reaction mechanism in guinea pig spermatozoa. © 1996 Wiley-Liss, Inc.     

DNA double-strand breaks, recombination and synapsis: the timing of meiosis differs in grasshoppers and flies

The temporal and functional relationships between DNA events of meiotic recombination and synaptonemal complex formation are a matter of discussion within the meiotic field. To analyse this subject in grasshoppers, organisms that have been considered as models for meiotic studies for many years, we have studied the localization of phosphorylated histone H2AX (gamma-H2AX), which marks the sites of double-strand breaks (DSBs), in combination with localization of cohesin SMC3 and recombinase Rad51. We show that the loss of gamma-H2AX staining is spatially and temporally linked to synapsis, and that in grasshoppers the initiation of recombination, produced as a consequence of DSB formation, precedes synapsis. This result supports the idea that grasshoppers display a pairing pathway that is not present in other insects such as Drosophila melanogaster, but is similar to those reported in yeast, mouse and Arabidopsis. In addition, we have observed the presence of gamma-H2AX in the X chromosome from zygotene to late pachytene, indicating that the function of H2AX phosphorylation during grasshopper spermatogenesis is not restricted to the formation of gamma-H2AX foci at DNA DSBs.     

Effects of brood parasitism on host reproductive success: evidence from larval interactions among dung beetles

This paper investigates the effect of brood parasitism in a dung beetle assemblage in an arid region of Spain. The study was conducted during the spring season (March-May 1994-1998) using mesh cylinders buried into the ground, filled with sand and with sheep dung on top. We quantified the proportion of nests containing larvae of parasitic beetles and their effect on host larvae survival. Experiments on the effect of parasitic larvae on host-larvae survival were conducted by placing scarab brood masses (raised from captive scarabs in the laboratory) in containers with and without aphodiid larvae. During the spring, dung desiccation is rapid, preventing aphodiids nesting in the dung, and forcing these species to adopt brood parasitism as a nesting strategy. Parasitic aphodiids were found in 12-47% of scarab nests of three species. The incidence of brood parasitization was positively related with the number of brood masses contained in the nests, being also higher in the most abundant species. Field data and experiments showed that brood parasites significantly reduced host larvae survival from 74.8% in non-parasitized nests to 8.8% in parasitized nests. Because different rates of nest parasitization and mortality were caused by parasites, brood parasitism had a differential effect on different host species. Thus, brood parasitism constitutes an important mortality factor reducing the reproductive success of the host species and potentially affecting the beetle abundance in the area.     

Biophysical evidence of lipid and carbohydrate binding activities of shrimp high density lipoprotein/beta glucan binding protein

Crustacean High Density Lipoprotein/beta-Glucan Binding Protein (HDL/BGBP) has been studied due to its role in nutrition and immune response via activation of the defense cells (hemocytes) upon binding 1,3-D-beta-glucan carbohydrates. In this study, HDL/BGBP was found to be composed mainly of beta sheets, as determined by circular dichroism. Lipoprotein aggregation resulted when HDL/BGBP interacted with phospolipid vesicles, laminaribiose (1,3-beta-glucan disaccharide) or heparin. HDL/BGBP has similar dissociation constants for laminaribiose (K(d)=22 mM) or heparin (K(d)=46 mM) as determined by 90 degrees light scattering.     

Highly specific inactivation of triosephosphate isomerase from Trypanosoma cruzi

We searched for molecules that selectively inactivate homodimeric triosephosphate isomerase from Trypanosoma cruzi (TcTIM), the parasite that causes Chagas' disease. We found that some benzothiazoles inactivate the enzyme. The most potent were 3-(2-benzothiazolylthio)-propanesulfonic acid, 2-(p-aminophenyl)-6-methylbenzothiazole-7-sulfonic acid, and 2-(2-4(4-aminophenyl)benzothiazole-6-methylbenzothiazole-7-sulfonic acid. Half-maximal inactivation by these compounds was attained with 33, 56, and 8 microM, respectively; in human TIM, half-maximal inactivation required 422 microM, 3.3 mM, and 1.6 mM. In TcTIM, the effect of the benzothiazoles decreased as the concentration of the enzyme was increased. TcTIM has a cysteine (Cys 15) at the dimer interface, whereas human TIM has methionine in that position. In M15C human TIM, the benzothiazole concentrations that caused half-maximal inactivation were much lower than in the wild type. The overall findings suggest that the benzothiazoles perturb the interactions between the two subunits of TcTIM through a process in which the interface cysteine is central in their deleterious action.     

Vitamin D Status: A Different Story in the Very Young versus the Very Old Romanian Patients

BackgroundIn Romania (latitude 48°15’N to 43°40’N), vitamin D supplementation is common practice mostly in infants 0-1 year old. No published information is available regarding epidemiological data on vitamin D status in the Romanian population for a wide age range and geographical territory. In this context, we aimed to evaluate the seasonal and age variation of vitamin D status in a large Romanian population.Methods6631 individuals from across Romania had performed 7544 vitamin D assessments (2012-2014) in a chain of private laboratories. Vitamin D (25-hydroxyvitamin D2 and 25-hydroxyvitamin D3) was measured using High Performance Liquid Chromatography. Vitamin D levels were classified as severe deficiency<10ng/mL, deficiency 10-20ng/mL, insufficiency 21-29ng/mL, sufficiency≥30ng/mL and potentially harmful>100ng/ml.ResultsMale to female ratio was 1:2.9. Age ranged from 0 to 85 years. Mean vitamin D levels increased from April (26.3ng/ml) to September (35.6ng/ml) and decreased from October (33.5ng/ml) to March (24.4 ng/ml). Overall 40% had sufficient vitamin D, while the rest were insufficient 33%, deficient 22%, severely deficient 4% and 1% potentially harmful (of them 81% under 1 year old). Males compared to females showed higher percentages of sufficiency (47% vs. 38%). Children 0- 2 years presented the highest percentage of vitamin D sufficiency (77%). Lowest percentages (21%) of sufficiency were in people 80-84 years.ConclusionIn Romania, suboptimal vitamin D levels are common (59%), especially in older age, wintertime and in women. Vitamin D supplementation would be most warranted from January to April in the Romanian population. 25-hydroxyvitamin D levels>100ng/ml were relatively prevalent in children 0-1 year old (17.3%). This was attributed to supplementation errors and the fact that high-risk individuals were more likely to visit for medical check-up. Nonetheless, it stresses the need to increase awareness of the importance of preventing Vitamin D supplementation administration errors in the young.