The ant Lasius niger shows no relationship between task efficiency and body size variation among workers

In ants, workers of different sizes may perform various tasks, even in so-called monomorphic species with relatively low body size variation. However, it is unclear if the body size diversity of monomorphic workers correlates with task efficiency, especially in stressful contingencies. Here we tested if the body size variation of workers corresponds with its efficiency in transferring pupae. Transferring brood is a pre-set behavioral response to stress, e.g. suboptimal temperature. Here we applied a laboratory experiment simulating nest damage. The study was performed on the common garden ant (Lasius niger (Linnaeus, 1758)) – a species with no distinct worker subcastes. The efficiency of workers was measured as the latency of transferring pupae from a lit part of the experimental colony to a darkened part, while the body size diversity was expressed as the within-colony coefficient of variation in head width. We did not find any significant correlation between efficiency and body size variation. Summarizing the existing studies and the present results, we propose the hypothesis that the body size diversity of L. niger may have implications for workers’ division of labor but not for their task efficiency in a stressful contingency.     

Asymmetric induction in the [4+2]cycloaddition of cyclopentadiene and furan to chiral derivatives of fumaric acid.

[4+2]Cycloaddition reactions of cyclopentadiene (1a) and furan (1b) to N,N'-fumaroyldi[(2R)-bornane-10,2-sultam] (2) and to N,N'-fumaroyldi[(2R)-bornane-10,2-(2'-phenyl-pyrazol-3'-one)] (3) are presented. A correlation between the solvent polarity and the logarithm of the diastereoisomer ratio (dr) was found for the uncatalyzed [4+2]cycloaddition of 1a to 3.     

Study on the influence of cranberry extract ?uravit S·O·S(?) on the properties of uropathogenic Escherichia coli strains, their ability to form biofilm and its antioxidant properties

Consumption of cranberries is known to exert positive health effects, especially against urinary tract infections. For this reason, presumably, they are widely used in folk medicine. Different aspects of cranberry phenolics activity were studied in individual papers but complex study in this matter is missing. The aim of the present study is to provide complex data concerning various aspects of cranberry extract activity. We studied the effects of subinhibitory concentrations of commercially available extract (?uravit S·O·S(?)) against two Escherichia coli strains isolated from urine of patients with pyelonephritis. Additionally the main extract anthocyanins were characterized. The activity of extract against lipid peroxidation and its radical scavenging ability were also assessed. ?uravit S·O·S(?) decreased the hydrophobicity of one of the studied E. coli strains, reduced swimming motility and adhesion to epithelial cells of both studied strains, it also limited the ability of bacteria to form biofilm. Expression of curli was not affected by cranberry extract, the assessment of P fimbriae expression was not reliable due to extract-induced agglutination of erythrocytes. Cranberry extract caused filamentation in both studied E. coli strains. It also showed pronounced antioxidant and radical scavenging properties. The properties of the studied cranberry extract show that it could be effectively used in prevention and/or elimination of urinary tract infections, specially the recurrent ones.     

Mercury in wild terrestrial carnivorous mammals from north-western Poland and unusual fish diet of red fox

Total mercury concentrations were determined in the kidney (K), liver (L), and pectoral muscle (M) of 19 individuals representing wild carnivorous mammals from NW Poland: 10 red foxes Vulpes vulpes (Linnaeus, 1758), 3 raccoon dogs Nyctereutes procyonoides Gray, 1834, 2 badgers Meles meles Linnaeus, 1758, 3 pine martens Martes martes Linnaeus, 1758, and 1 polecat Mustela putorius Linnaeus, 1758. The sample of red fox included 3 immature specimens found on Mielin Island; the island supports a black cormorant colony, and the foxes found there had fed mostly on cormorant nestlings as well as on fish and their remains. In addition to the Mielin Island foxes, the group of foxes included 3 other immature and 4 adult individuals. The highest mean of mercury concentrations were revealed in the Mielin red fox juveniles: 5.11, 4.52, and 1.56 mg/kg d.w. being recorded in K, L, and M. No significant differences in mercury concentrations in the respective tissues were found between the remaining immature and adult red foxes; their mercury concentrations were several times lower than those of the Mielin individuals. In all the animals except the Mielin foxes, mercury concentrations in K, L, and M did not exceed 1.3, 1.0 and 0.5 mg/kg d.w., respectively, the highest values being in badgers (which feed mostly on soil invertebrates), followed by pine martens and then the canids (red fox and raccoon dog). Studies on common and widely distributed terrestrial animals, particularly red fox and badger, may provide numerous valuable comparative data on mercury contamination of different areas of the northern hemisphere.     

Cyr61 activates retinal cells and prolongs photoreceptor survival in rd1 mouse model of retinitis pigmentosa

Subretinal injections with glial cell line‐derived neurotrophic factor (GDNF) rescue morphology as well as function of rod cells in mouse and rat animal models of retinitis pigmentosa. At the same time, it is postulated that this effect is indirect, mediated by activation of retinal Müller glial (RMG) cells. Here, we show that Cyr61/CCN1, one of the secreted proteins up‐regulated in primary RMG after glial cell line‐derived neurotrophic factor stimulation, provides neuroprotective and pro‐survival capacities: Recombinant Cyr61 significantly reduced photoreceptor (PR) cells death in organotypic cultures of Pde6b^rd1 retinas. To identify stimulated pathways in the retina, we treated Pde6b^rd1 retinal explants with Cyr61 and observed an overall increase in activated Erk1/2 and Stat3 signalling molecules characterized by activation‐site‐specific phosphorylation. To identify Cyr61 retinal target cells, we isolated primary porcine PR, RMG and retinal pigment epithelium (RPE) cells and exposed them separately to Cyr61. Here, RMG as well as RPE cells responded with induced phosphorylation of Erk1/2, Stat3 and Akt. In PR, no increase in phosphorylation in any of the studied proteins was detected, suggesting an indirect neuroprotective effect of Cyr61. Cyr61 may thus act as an endogenous pro‐survival factor for PR, contributing to the complex repertoire of neuroprotective activities generated by RMG and RPE cells.

     

The influence of the cooling of donor cultures on the in vitro adventitious regeneration and carbohydrate metabolism of four dwarfing apple rootstocks

We examined the effects of cooling applied for 4 to 20 weeks on donor cultures of four dwarfing apple rootstocks (P16, P22, P59 and M26). Our aim includes increasing their competence for in vitro adventitious shoot regeneration from the leaves. Donor cultures were maintained on a shoot multiplication medium at 4°C in the dark for 4 months, followed by subculture on a fresh medium for 4 weeks. The cooling of the cultures caused an increase in the adventitious shoot number and a decrease in the starch content and an increase in the soluble sugar content (monosaccharides, raffinose and stachyose). The accumulation of stachyose in response to cold is a new observation, and it suggests that raffinose and stachyose play important role in the acclimation of dwarf apple rootstocks to low temperatures.     

Regulation of the inducible nuclear dual-specificity phosphatase DUSP5 by ERK MAPK

DUSP5 is an inducible, nuclear, dual-specificity phosphatase, which specifically interacts with and inactivates the ERK1/2 MAP kinases in mammalian cells. In addition, expression of DUSP5 causes nuclear translocation of ERK2 indicating that it may act as a nuclear anchor for the inactive kinase. Here we show that induction of DUSP5 mRNA and protein in response to growth factors is dependent on ERK1/2 activation and that the accumulation of DUSP5 protein is regulated by rapid proteasomal degradation. DUSP5 is phosphorylated by ERK1/2 both in vitro and in vivo on three sites (Thr321, Ser346 and Ser376) within its C-terminal domain. DUSP5 phosphorylation is absolutely dependent on the conserved kinase interaction motif (KIM) within the amino-terminal domain of DUSP5, indicating that the same protein–protein contacts are required for both the inactivation of ERK2 by DUSP5 and for DUSP5 to act as a substrate for this MAPK. Using a combination of pharmacological inhibitors and phospho-site mutants we can find no evidence that phosphorylation of DUSP5 by ERK2 significantly affects either the half-life of the DUSP5 protein or its ability to bind to, inactivate or anchor ERK2 in the nucleus. However, co-expression of ERK2 results in significant stabilisation of DUSP5, which is accompanied by reduced levels of DUSP5 ubiquitination. These changes are independent of ERK2 kinase activity but absolutely depend on the ability of ERK2 to bind to DUSP5. We conclude that DUSP5 is stabilised by complex formation with its physiological substrate and that this may reinforce its activity as both a phosphatase and nuclear anchor for ERK2.     

Structural details of monoclonal antibody m971 recognition of the membrane-proximal domain of CD22

Cluster of differentiation-22 (CD22) belongs to the sialic acid–binding immunoglobulin (Ig)-like lectin family of receptors that is expressed on the surface of B cells. It has been classified as an inhibitory coreceptor for the B-cell receptor because of its function in establishing a baseline level of B-cell inhibition. The restricted expression of CD22 on B cells and its inhibitory function make it an attractive target for B-cell depletion in cases of B-cell malignancies. Genetically modified T cells with chimeric antigen receptors (CARs) derived from the m971 antibody have shown promise when used as an immunotherapeutic agent against B-cell acute lymphoblastic leukemia. A key aspect of the efficacy of this CAR-T was its ability to target a membrane-proximal epitope on the CD22 extracellular domain; however, the molecular details of m971 recognition of CD22 have thus far remained elusive. Here, we report the crystal structure of the m971 fragment antigen-binding in complex with the two most membrane-proximal Ig-like domains of CD22 (CD22_d6–d7). The m971 epitope on CD22 resides at the most proximal Ig domain (d7) to the membrane, and the antibody paratope contains electrostatic surfaces compatible with interactions with phospholipid head groups. Together, our data identify molecular details underlying the successful transformation of an antibody epitope on CD22 into an effective CAR immunotherapeutic target.