Decrease in circulating DNA, IL-10 and BAFF levels in newly-diagnosed SLE patients after corticosteroid and chloroquine treatment

Arsenal of pattern-recognition receptors alongside antibody production machinery make B cells vulnerable to autoimmune response if an autoantigen elicits both pathways in a self-sustained fashion. Systemic lupus erythematosus is an autoimmune disease characterized by autoantibodies to DNA, RNA and related structures. Murine studies demonstrated autoreactive B cell activation upon TLR9 stimulation with DNA-containing immune complexes. This activation could be abolished with chloroquine, a drug used in SLE treatment that also blocks TLR9 signaling. We investigated whether chloroquine modulates TLR9 expression, circulating DNA levels and B cell-related cytokines in newly discovered, untreated SLE patients. TLR9 was measured in peripheral blood B cells by flow cytometry, serum DNA by real-time PCR, and IL-10 and BAFF by ELISA before treatment, after 3weeks on corticosteroids, and 3months after introduction of chloroquine. We found that circulating DNA is higher in SLE patients than in controls in every time-point and decreases significantly after chloroquine treatment. Untreated patients had higher serum IL-10 than controls or patients on corticosteroids. Also, corticosteroids decreased and chloroquine completely abolished CpG-mediated CD86 upregulation on B cells and IL-10 secretion in PBMC culture. Providing the TLR9 pathway activation demonstrates its importance in pathogenesis of human SLE, this data supports continuation of chloroquine in SLE treatment protocol. In addition, observed modulation of cytokine and DNA levels after immunomodulatory treatment prompts for inclusion of untreated patients in studies of human immune disorders.     

The evolution and phytoplankton composition of mucilaginous aggregates in the northern Adriatic Sea

Recurrent occurrences of visible mucilage “clouds” that cover areas up to several hundred kilometres with vertical dimensions of 20–30 m have been recorded in the stratified water column in the northern Adriatic. In the past this was described as “mare sporco” phenomenon. Past studies of the phenomenon indicated that phytoplankton is an important component of mucilage. Our research revealed the composition of phytoplankton assemblages in different types of mucilaginous aggregates collected during the summers of 1997 and 2000 using pigment biomarkers (HPLC). Phytoplankton biomass in the mucilage samples was very high, ranging from 7.9 μg g⁻¹ to 390.8 μg g⁻¹ of chlorophyll a per unit of dry mass of mucilage. The phytoplankton community in the early, loose stage of mucilaginous aggregates was heterogeneous, as indicated by the diversity of detected pigments. The number of phytoplankton groups decreased as the aggregates aged and diatoms increased in relative biomass (up to 92.7%). Phytoplankton biomass in seawater was similar in years with and without mucilage; however, significantly higher contributions to the total biomass of 19′-hexanoyloxyfucoxanthin-containing phytoplankton (prymnesiophytes) were found in the upper 10 m in spring of the “mucilaginous years” (1997 and 2000) followed by prevalence of diatoms in summer. The F_p pigment index used to assess seawater trophic conditions reached lower values in April–May in mucilaginous years (1997 and 2000) compared to non-mucilaginous years (1998 and 1999). We conclude that the role of prymnesiophytes and other small flagellates is crucial for the initial phases of mucilage appearance. Aggregates represent a favourable environment for the secondary development of opportunistic diatoms that foster mucilage formation.     

The influence of enhanced UV-B radiation on the spring geophyte Pulmonaria officinalis

Pulmonaria officinalis is an understorey spring geophyte, which starts its vegetative period before full foliation of the tree storey. During its early growth phase it is exposed to full solar radiation, therefore the enhanced UV-B radiation could present a threat to this species. An outdoor experiment in which potted plants were exposed to below ambient, ambient, and above ambient (corresponding to 17% ozone reduction) UV-B radiation, was conducted in order to evaluate the radiation effects. The amount of photosynthetic pigments and photochemical efficiency of PSII were not affected, but the amount of UV-B absorbing compounds was lower in plants grown under reduced UV-B. This change was measurable after only fourteen days in reproductive shoots, while in the vegetative shoots, it was not detectable until after three months. The leaves of P. officinalis are variegated and the light green spots became less transparent to PAR under enhanced UV-B. The results reveal that under simulated 17% ozone depletion the harmful effects of UV-B on the measured parameters were negligible.     

Jasmonic acid stimulates shoot and bulb formation of garlic in vitro

Although much information is available concerning the involvement of jasmonates in the regulation of plant development, few reports are devoted to their effects in tissue culture. In the present study, the influence of jasmonic acid (JA) on shoot and bulb formation in tissue culture of garlic (Allium sativum cv. Ptuj) was studied. Isolated basal plates were placed onto Gamborg's B5 medium. JA significantly enhanced the shoot and bulb development in concentrations from 1–10 M. When the combination of 10 M JA and 5 M 2-iP was used in the initiation media, the average number of shoots was 30 after 6 weeks of culture. The bulbs formed on approximately 50% of shoots. Results described in this article show that JA might play an important role in the formation of storage organs in plants, in this case on garlic bulbs.     

Actin polymerization promotes the reversal of streaming in the apex of pollen tubes

Actin polymerization is important in the control of pollen tube growth. Thus, treatment of pollen tubes with low concentrations of latrunculin B (Lat-B), which inhibits actin polymerization, permits streaming but reversibly blocks oscillatory growth. In the current study, we employ Jasplakinolide (Jas), a sponge cyclodepsipeptide that stabilizes actin microfilaments and promotes polymerization. Uniquely, Jas (2 microM) blocks streaming in the shank of the tube, but induces the formation of a toroidal-shaped domain in the swollen apex, of which longitudinal optical sections exhibit circles of motion. The polarity of this rotary motion is identical to that of reverse fountain motility in control pollen tubes, with the forward direction occurring at the edge of the cell and the rearward direction in the cell interior. Support for the idea that actin polymerization in the apical domain contributes to the formation of this rotary motility activity derives from the appearance therein of aggregates and flared cables of F-actin, using immunofluorescence, and by the reduction in G-actin as indicated with fluorescent DNAse. In addition, Jas reduces the tip-focused Ca2+ gradient. However, the alkaline band appears in the swollen apex and is spatially localized with the reverse fountain streaming activity. Taken together, our results support the idea that actin polymerization promotes reversal of streaming in the apex of the lily pollen tube.     

Interleukin-1alpha production in human corneal scars

We studied IL-1alpha level in corneal scars with/without neo-vascularization. A total of 27 patients underwent grafting for corneal scar. Recipients were grouped according to number of vascularized quadrants (0 to IV/IV): none (n = 12), one (n = 5), two (n = 4) and four (n = 6). Recipient corneas were collected during surgery and IL-1alpha measured by immunoassay. Controls were donor corneas unsuitable for transplantation. Graft rejection rate was calculated for each group. Mean IL-1alpha concentration in corneal scars was 6 +/- 3.93 pg/mm3; significantly higher as compared to controls (1.25 +/- 2.03 pg/mm3). IL-1alpha correlated well with amount of blood vessels, except in IV/IV scars: 5.17 +/- 3.65 pg/mm3 for 0/IV; 8.02 +/- 2.51 pg/mm3 for I/IV; 8.27 +/- 3.62 pg/mm3 for II/IV and 4.47 +/- 5.03 pg/mm3 for IV/IV corneal scars. Vascularization of corneal scar is associated with increased IL-1alpha level (in all but highly vascularized scars), indicating that IL-1alpha promotes early stages of vascularization. Graft rejection rate increases in patients with higher vascularization, independently of IL-1alpha level.     

Fatty Acid Elongation Is Independent of Acyl-Coenzyme A Synthetase Activities in Leek and Brassica napus

In both animal and plant acyl elongation systems, it has been proposed that fatty acids are first activated to acyl-coenzyme A (CoA) before their elongation, and that the ATP dependence of fatty acid elongation is evidence of acyl-CoA synthetase involvement. However, because CoA is not supplied in standard fatty acid elongation assays, it is not clear if CoA-dependent acyl-CoA synthetase activity can provide levels of acyl-CoAs necessary to support typical rates of fatty acid elongation. Therefore, we examined the role of acyl-CoA synthetase in providing the primer for acyl elongation in leek (Allium porrum L.) epidermal microsomes and Brassica napus L. cv Reston oil bodies. As presented here, fatty acid elongation was independent of CoA and proceeded at maximum rates with CoA-free preparations of malonyl-CoA. We also showed that stearic acid ([1-¹⁴C]18:0)-CoA was synthesized from [1-¹⁴C]18:0 in the presence of CoA-free malonyl-CoA or acetyl-CoA, and that [1-¹⁴C]18:0-CoA synthesis under these conditions was ATP dependent. Furthermore, the appearance of [1-¹⁴C]18:0 in the acyl-CoA fraction was simultaneous with its appearance in phosphatidylcholine. These data, together with the s of a previous study (A. Hlousek-Radojcic, H. Imai, J.G. Jaworski [1995] Plant J 8: 803–809) showing that exogenous [¹⁴C]acyl-CoAs are diluted by a relatively large endogenous pool before they are elongated, strongly indicated that acyl-CoA synthetase did not play a direct role in fatty acid elongation, and that phosphatidylcholine or another glycerolipid was a more likely source of elongation primers than acyl-CoAs.