Expansion of functionally anergic CD21-/low marginal zone-like B cell clones in hepatitis C virus infection-related autoimmunity

Homeostasis of peripheral B cell subsets is disturbed during chronic hepatitis C virus (HCV) infection, leading to the occurrence of autoimmunity and B cell lymphoproliferation. However, mechanisms by which HCV causes lymphoproliferation remain controversial. We report in this article on the elevated number of clonal CD21(-/low)IgM(+)CD27(+) marginal zone (MZ)-like B cells, which correlates with autoimmunity and lymphoproliferation in HCV patients. We found an increase in autoreactive BCRs using V(H)1-69 and V(H)4-34 genes in CD21(-/low) MZ B cells. CD21(-/low) MZ B cells showed impaired calcium-mediated signaling, did not upregulate activation markers, and did not proliferate in response to BCR triggering. CD21(-/low) MZ B cells also were prone to dying faster than their CD21(+) counterparts, suggesting that these B cells were anergic. CD21(-/low) MZ B cells, in contrast, remained responsive to TLR9 stimulation. Gene array analyses revealed the critical role of Early growth response 2 and Cbl-b in the induction of anergy. Therefore, HCV patients who display high frequencies of unresponsive CD21(-/low) MZ B cells are more susceptible to developing autoimmunity and/or lymphoproliferation. These cells remain in peripheral blood controlled by functional anergy instead of being eliminated, and chronic antigenic stimulation through TLR stimulation may create a favorable environment for breaking tolerance and activating these cells.     

Recovery of Pseudomonas spp. from chronically fuel oil-polluted soils in Jordan and the study of their capability to degrade short chain alkanes

Enumeration of bacteria and recovery of the dominant species have been conducted for soils contaminated with fuel spills for more than 10 years at seven gas stations in Jordan. Bacterial counts of these polluted soils ranged between 0.68 × 10⁸ and 32.8 × 10⁸ c.f.u./g soil with two different bacterial colony types recovered on agar plates. Phenotypic examination of the recovered bacteria revealed that they belonged mainly to the genus Pseudomonas and was represented by the following species: P. acidovorans, P. putrefaciens, P. cepacia, P. vesicularis and P. fluorescens. The ability of these bacteria to grow on hexane or heptane was revealed by a colorimetric test. Action of five Pseudomonas spp.: Pseudomonas putrefaciens, P. cepacia, P. acidovorans, P. vesicularis and P. fluorescens and Rhodococcus erythropolis on 0.1% (v/v) hexane or heptane was followed at 1, 2, 6 and 12 h. Pseudomonas putrefaciens, P. cepacia and P. acidovorans were capable of degrading both hydrocarbons as indicated by the yellow colour formation (positive reaction); however, P. vesicularis and P. fluorescens showed no such capability.     

Fluid Secretion in Rhodnius Upper Malpighian Tubules (UMT): Water Osmotic Permeabilities and Morphometric Studies

We have measured the osmotic permeability of the basolateral cell membrane (Poscb) and compared it with the transepithelial permeability (Poste) to calculate the paracellular (Posp) permeability of the upper malpighian tubules (UMT) of the 5th instar of Rhodnius prolixus under several experimental conditions, namely, at rest and after stimulation to secrete with 5-HT, each under control conditions (no treatment), after treatment with pCMBS, and after addition of pCMBS and DTT. Secretion rate is negligible at rest. During stimulation mean secretion rate is 43.5 nl/cm2 sec. Secretion is severely curtailed by pCMBS and fully restored by DTT. Poscb = 9.4 (resting, control); 5.8 (control + pCMBS); 10.7 (control + pCMBS + DTT); 20.6 (stimulated, control); 14.7 (stimulated + pCMBS); 49.1 (stimulated + pCMBS + DTT) (x10?4 cm3/cm2 sec Osm). Calculated Posp are higher than the transcellular permeability, Posc, at rest and after stimulation. Electron micrograph morphometry of UMT sections show that cells significantly decrease their volume after stimulation. Lateral intercellular space (LIS) and basolateral extracellular labyrinth (BEL) are barely discernible at rest. LIS and BEL are widely dilated in stimulated UMT. Thus, ions have restricted access to the deep and narrow basolateral cell membrane indentations at rest, but they have ready access to cell membrane indentations after stimulation, because of the opening of LIS and BEL. These findings are discussed in relation to isosmotic secretion. The rate-limiting step for paracellular movement is located at the smooth septate junctions.     

IGF-1 activates hEAG K(+) channels through an Akt-dependent signaling pathway in breast cancer cells: role in cell proliferation

Previous work from our laboratory has shown that human ether à go-go (hEAG) K(+) channels are crucial for breast cancer cell proliferation and cell cycle progression. In this study, we investigated the regulation of hEAG channels by an insulin-like growth factor-1 (IGF-1), which is known to stimulate cell proliferation. Acute applications of IGF-1 increased K(+) current-density and hyperpolarized MCF-7 cells. The effects of IGF-1 were inhibited by hEAG inhibitors. Moreover, IGF-1 increased mRNA expression of hEAG in a time-dependent manner in parallel with an enhancement of cell proliferation. The MCF-7 cell proliferation induced by IGF-1 is inhibited pharmacologically by Astemizole or Quinidine or more specifically using siRNA against hEAG channel. Either mitogen-activated protein kinase (MAPK) or phosphatidylinositol 3-kinase (PI3K) are known to mediate IGF-1 cell proliferative signals through the activation of extracellular signal-regulated kinase 1/2 (Erk 1/2) and Akt, respectively. In MCF-7 cells, IGF-1 rapidly stimulated Akt phosphorylation, whereas IGF-1 had little stimulating effect on Erk 1/2 which seems to be constitutively activated. The application of wortmannin was found to block the effects of IGF-1 on K(+) current. Moreover, the inhibition of Akt phosphorylation by the application of wortmannin or by a specific reduction of Akt kinase activity reduced the hEAG mRNA levels. Taken together, our results show, for the first time, that IGF-1 increases both the activity and the expression of hEAG channels through an Akt-dependent pathway. Since a hEAG channel is necessary for cell proliferation, its regulation by IGF-1 may thus play an important role in IGF-1 signaling to promote a mitogenic effect in breast cancer cells.     

Activity of North Jordan soil streptomycete isolates against Candida albicans

Eighteen percent of 116 different isolates of Streptomyces recovered from soils of northern Jordan showed activity against Candida albicans. The recovered isolates were distributed into three groups according to the diameter of the inhibition zone on the agar plate: group 1 (5–10 mm, slightly active); group 2 (11–15 mm, moderately active); and group 3 (16–35 mm, highly active). Isolates of group 3 were further grouped into four sub-groups and were culturally and morphologically identified. The u.v. spectra of the fermentation broth for the isolates in sub-group 4 were determined, and showed absorbance peaks ranging between 230 and 300 nm.     

Limited Contribution of IL-36 versus IL-1 and TNF Pathways in Host Response to Mycobacterial Infection

IL-36 cytokines are members of the IL-1 family of cytokines that stimulate dendritic cells and T cells leading to enhanced T helper 1 responses in vitro and in vivo; however, their role in host defense has not been fully addressed thus far. The objective of this study was to examine the role of IL-36R signaling in the control of mycobacterial infection, using models of systemic attenuated M. bovis BCG infection and virulent aerogenic M. tuberculosis infection. IL-36γ expression was increased in the lung of M. bovis BCG infected mice. However, IL-36R deficient mice infected with M. bovis BCG showed similar survival and control of the infection as compared to wild-type mice, although their lung pathology and CXCL1 response were transiently different. While highly susceptible TNF-α deficient mice succumbed with overwhelming M. tuberculosis infection, and IL-1RI deficient mice showed intermediate susceptibility, IL-36R-deficient mice controlled the infection, with bacterial burden, lung inflammation and pathology, similar to wild-type controls. Therefore, IL-36R signaling has only limited influence in the control of mycobacterial infection.     

Growth of <Emphasis Type="Italic">Streptomyces</Emphasis> spp. from hydrocarbon-polluted soil on diesel and their analysis for the presence of alkane hydroxylase gene (<Emphasis Type="Italic">alkB</Emphasis>) by PCR

The investigation aimed to examine the Streptomyces flora of hydrocarbon-contaminated soil and study their capability to grow on diesel fuel as a sole carbon source and their analysis for the presence of the alkane hydroxylase gene (alkB) by PCR. A total of 16 Streptomyces isolates were recovered from hydrocarbon-contaminated soil samples on starch casein nitrate agar medium with the ability of 3 isolates to grow on diesel as evaluated by agar plate diffusion method, enzymatic assay and dry weight measurements. PCR analysis of the isolates for the presence of the alkB gene showed two groups with different band size products; group 1 (G1) (316–334 bp) and group 2 (G2) (460–550 bp). Three isolates (SF.1Ac, SF.2Ba, and SF.3Ad) grew around diesel-containing wells and contained the alkB gene with size band ranged between 320 and 550 bp. However; one isolate (SF.1Aa) did not show any PCR product although it was able to grow on diesel. This implies that the alkB gene is not the only gene that is responsible for the degradation of alkanes. Further, the variation in the G2 fragment size probably indicates different related genes that might be involved in alkane degradation rather than a single gene.     

SSR markers and seed quality traits revealed genetic diversity in durum wheat (Triticum durum Desf.)

Molecular Biology Reports - Genetic diversity and differences among durum-wheat cultivars evolved in various regions of the world are important for sustainable production in the current climate...     

Restoration of regulatory and effector T cell balance and B cell homeostasis in systemic lupus erythematosus patients through vitamin D supplementation

Introduction

Systemic lupus erythematosus (SLE) is a T and B cell-dependent autoimmune disease characterized by the appearance of autoantibodies, a global regulatory T cells (Tregs) depletion and an increase in Th17 cells. Recent studies have shown the multifaceted immunomodulatory effects of vitamin D, notably the expansion of Tregs and the decrease of Th1 and Th17 cells. A significant correlation between higher disease activity and lower serum 25-hydroxyvitamin D levels [25(OH)D] was also shown.

Methods

In this prospective study, we evaluated the safety and the immunological effects of vitamin D supplementation (100 000 IU of cholecalciferol per week for 4 weeks, followed by 100 000 IU of cholecalciferol per month for 6 months.) in 20 SLE patients with hypovitaminosis D.

Results

Serum 25(OH)D levels dramatically increased under vitamin D supplementation from 18.7±6.7 at day 0 to 51.4±14.1 (p<0.001) at 2 months and 41.5±10.1 ng/mL (p<0.001) at 6 months. Vitamin D was well tolerated and induced a preferential increase of naïve CD4⁺ T cells, an increase of regulatory T cells and a decrease of effector Th1 and Th17 cells. Vitamin D also induced a decrease of memory B cells and anti-DNA antibodies. No modification of the prednisone dosage or initiation of new immunosuppressant agents was needed in all patients. We did not observe SLE flare during the 6 months follow-up period.

Conclusions

This preliminary study suggests the beneficial role of vitamin D in SLE patients and needs to be confirmed in randomized controlled trials.     

Isolation of Cronobacter spp. (formerly Enterobacter sakazakii) from infant food, herbs and environmental samples and the subsequent identification and confirmation of the isolates using biochemical, chromogenic assays, PCR and 16S rRNA sequencing

Background  

Cronobacter spp. (formerly Enterobacter sakazakii), are a group of Gram-negative pathogens that have been implicated as causative agents of meningitis and necrotizing enterocolitis in infants. The pathogens are linked to infant formula; however, they have also been isolated from a wide range of foods and environmental samples.