Interferon-gamma and sinusoidal electric fields signal by modulating NAD(P)H oscillations in polarized neutrophils

Metabolic activity in eukaryotic cells is known to naturally oscillate. We have recently observed a 20-s period NAD(P)H oscillation in neutrophils and other polarized cells. Here we show that when polarized human neutrophils are exposed to interferon-gamma or to ultra-low-frequency electric fields with periods double that of the NAD(P)H oscillation, the amplitude of the NAD(P)H oscillations increases. Furthermore, increases in NAD(P)H amplitude, whether mediated by interferon-gamma or by an oscillating electric field, signals increased production of reactive oxygen metabolites. Hence, amplitude modulation of NAD(P)H oscillations suggests a novel signaling mechanism in polarized cells.     

Differential intracellular distributions of inositol trisphosphate and ryanodine receptors within and among hematopoietic cells.

To better understand the mechanism(s) of leukocyte Ca(2+) signaling, we have studied the intracellular locations of two Ca(2+)-mobilizing receptors, the inositol 1,4,5-trisphosphate receptor and ryanodine receptor, by immunofluorescence microscopy. Our results show that localization differs not only between receptor classes within a cell, but among leukocyte types as well. We also illustrate the importance of preserving labile cellular filaments in maintaining cell integrity by fixation with the Safiejko-Mroczka and Bell protocol, because conventional fixation methods distort receptor patterns. We suggest that the observed differences influence intracellular Ca(2+) signaling.     

Chimpanzees (Pan troglodytes) Produce the Same Types of ‘Laugh Faces’ when They Emit Laughter and when They Are Silent

The ability to flexibly produce facial expressions and vocalizations has a strong impact on the way humans communicate, as it promotes more explicit and versatile forms of communication. Whereas facial expressions and vocalizations are unarguably closely linked in primates, the extent to which these expressions can be produced independently in nonhuman primates is unknown. The present work, thus, examined if chimpanzees produce the same types of facial expressions with and without accompanying vocalizations, as do humans. Forty-six chimpanzees (Pan troglodytes) were video-recorded during spontaneous play with conspecifics at the Chimfunshi Wildlife Orphanage. ChimpFACS was applied, a standardized coding system to measure chimpanzee facial movements, based on FACS developed for humans. Data showed that the chimpanzees produced the same 14 configurations of open-mouth faces when laugh sounds were present and when they were absent. Chimpanzees, thus, produce these facial expressions flexibly without being morphologically constrained by the accompanying vocalizations. Furthermore, the data indicated that the facial expression plus vocalization and the facial expression alone were used differently in social play, i.e., when in physical contact with the playmates and when matching the playmates’ open-mouth faces. These findings provide empirical evidence that chimpanzees produce distinctive facial expressions independently from a vocalization, and that their multimodal use affects communicative meaning, important traits for a more explicit and versatile way of communication. As it is still uncertain how human laugh faces evolved, the ChimpFACS data were also used to empirically examine the evolutionary relation between open-mouth faces with laugh sounds of chimpanzees and laugh faces of humans. The ChimpFACS results revealed that laugh faces of humans must have gradually emerged from laughing open-mouth faces of ancestral apes. This work examines the main evolutionary changes of laugh faces since the last common ancestor of chimpanzees and humans.     

PDADMAC flocculation of Chinese hamster ovary cells: Enabling a centrifuge-less harvest process for monoclonal antibodies

High titer (>10 g/L) monoclonal antibody (mAb) cell culture processes are typically achieved by maintaining high viable cell densities over longer culture durations. A corresponding increase in the solids and sub-micron cellular debris particle levels are also observed. This higher burden of solids (≥15%) and sub-micron particles typically exceeds the capabilities of a continuous centrifuge to effectively remove the solids without a substantial loss of product and/or the capacity of the harvest filtration train (depth filter followed by membrane filter) used to clarify the centrate. We discuss here the use of a novel and simple two-polymer flocculation method used to harvest mAb from high cell mass cell culture processes. The addition of the polycationic polymer, poly diallyldimethylammonium chloride (PDADMAC) to the cell culture broth flocculates negatively-charged cells and cellular debris via an ionic interaction mechanism. Incorporation of a non-ionic polymer such as polyethylene glycol (PEG) into the PDADMAC flocculation results in larger flocculated particles with faster settling rate compared to PDADMAC-only flocculation. PDADMAC also flocculates the negatively-charged sub-micron particles to produce a feed stream with a significantly higher harvest filter train throughput compared to a typical centrifuged harvest feed stream. Cell culture process variability such as lactate production, cellular debris and cellular densities were investigated to determine the effect on flocculation. Since PDADMAC is cytotoxic, purification process clearance and toxicity assessment were performed.     

Growth of Quailbush in Acidic, Metalliferous Desert Mine Tailings: Effect of Azospirillum brasilense Sp6 on Biomass Production and Rhizosphere Community Structure

Mine tailing deposits in semiarid and arid environments frequently remain devoid of vegetation due to the toxicity of the substrate and the absence of a diverse soil microbial community capable of supporting seed germination and plant growth. The contribution of the plant growth promoting bacterium (PGPB) Azospirillum brasilense Sp6 to the growth of quailbush in compost-amended, moderately acidic, high-metal content mine tailings using an irrigation-based reclamation strategy was examined along with its influence on the rhizosphere bacterial community. Sp6 inoculation resulted in a significant (2.2-fold) increase in plant biomass production. The data suggest that the inoculum successfully colonized the root surface and persisted throughout the 60-day experiment in both the rhizosphere, as demonstrated by excision and sequencing of the appropriate denaturing gradient gel electrophoresis (DGGE) band, and the rhizoplane, as indicated by fluorescent in situ hybridization of root surfaces. Changes in rhizosphere community structure in response to Sp6 inoculation were evaluated after 15, 30, and 60 days using DGGE analysis of 16S rRNA polymerase chain reaction amplicons. A comparison of DGGE profiles using canonical correspondence analysis revealed a significant treatment effect (Sp6-inoculated vs. uninoculated plants vs. unplanted) on bacterial community structure at 15, 30, and 60 days (p?<?0.05). These data indicate that in an extremely stressed environment such as acid mine tailings, an inoculated plant growth promoting bacterium not only can persist and stimulate plant growth but also can directly or indirectly influence rhizobacterial community development.     

Growth responses of Matteuccia struthiopteris plants from northern and southern Norway exposed to different temperature and photoperiod treatments

Plants of the fern Matteuccia struthiopteris from northern and southern populations in Norway were studied in a phytotron. Relative growth rate (RGR), growth period, and sporophyll production were measured under different photoperiod (12–24 h) day-length and temperature (9–21 °C) treatments. For the southern plants, there were no significant differences between the different light treatments, but for the northern plants there was a significant (p<0.01) linear increase in the mean maximum RGR with increasing day-length. Small, but statistically significant (p<0.01) differences were found between northern and southern plants when the mean maximum RGR-values were compared. When plants from different origin were exposed to different treatment, there were major differences between the populations in the production of sporophylls (p<0.0001). Southern plants produced in average three times more sporophylls than the northern plants, and they had also higher proportions of fertile plants. Diurnal alternating temperature treatments gave no significant (p>0.05) effect on the mean maximum RGR compared with constant temperatures, but they gave significantly higher production of sporophylls. In general, the northern plants had a higher temperature threshold (approximately 12 °C) for sporophyll production than the southern plants (approximately 9 °C). Plants exposed to 24 h with natural light were generally more often fertile than plants exposed to a shorter photoperiod. The mean maximum RGR-values and time needed to develop the fronds at the 9 °C treatment were fairly equal to those found under natural conditions close to the altitudinal distribution limit of M.struthiopteris in W Norway. In general, the investigation showed that the applied temperature and light treatments affected sporophyll production more than vegetative growth.     

Plasmid profile and construction of a small shuttle vector in <Emphasis Type="Italic">Laribacter hongkongensis</Emphasis>

Among 21 human strains of Laribacter hongkongensis, small plasmids were observed in four strains, and large ones in six strains. The smallest, 3264-bp plasmid, pHLHK19, has only one ORF that encodes a putative replication initiator protein and a predicted origin of replication (ori) with a DnaA box, three 18-bp direct repeats and five pairs of inverted repeats. An Escherichia coli-L. hongkongensis shuttle vector was constructed by ligating the HindIII-digested pHLHK19, containing the replication initiator protein and ori of pHLHK19, to HindIII-digested pBK-CMV. This shuttle vector can propagate in E. coli and L. hongkongensis with good transformation efficiencies.     

Biotechnological exploitation of bacteriophage research

The experimentally amenable nature of phage and their use in testing fundamental biological questions have meant that phage research has had a profound effect on modern molecular biology. Phage research has also fuelled multiple biotechnological developments. For example, phage display has recently been harnessed in a multidisciplinary approach for the generation of novel nanotechnologies. In addition, with the emerging threat of antibiotic-resistant bacterial infections, phage have begun to provide technologies to combat these problems. Finally, recent data acquired from genome sequencing and advances in phage biology research have aided the development of phage-derived bacterial detection and treatment strategies in addition to methods to control the detrimental effects of phage in industry. Here, we examine the promising uses of phage in these important areas of biotechnology.