Zooplankton Composition and Ecology in Western Boreal Shallow-water Wetlands

Zooplankton are a functionally important but poorly studied component of western boreal forest (WBF) wetland ecosystems. To characterize patterns in zooplankton abundance and composition an exploratory study of 24 shallow-water wetlands in northern Alberta, Canada was carried out over the summers of 2001 and 2002. Results suggest zooplankton communities in WBF wetlands tend to exist as: (1) small-cladoceran dominated communities, (2) larger sized cladoceran (e.g. Daphnia) dominated communities, or (3) communities composed primarily of rotifers and/or other crustacean zooplankton. The presence/absence of brook stickleback (Culea inconstans) was the factor most strongly linked to zooplankton structure with small cladocerans tending to dominate in wetlands with stickleback. In fishless wetlands, communities dominated by medium-large sized cladocerans tended to correspond with low-chlorophyll/high-submerged aquatic vegetation (SAV) conditions. Conversely, communities composed of rotifers and other crustaceans were associated with high-chlorophyll/low-SAV states. Macro-invertebrate predator abundance was not strongly linked to patterns in zooplankton composition suggesting macro-invertebrate predation is not a significant factor influencing zooplankton structure in fishless wetlands. Results suggest activities that spread stickleback (e.g. ditching) or inhibit development of macrophyte-dominated/clear-water conditions (e.g. nutrient loading) may seriously alter the zooplankton community structure, and thereby the functional ecology, of these valuable wetland ecosystems.     

Human Survivin and Trypanosoma cruzi Calreticulin Act in Synergy against a Murine Melanoma In Vivo

Immune-based anti-tumor or anti-angiogenic therapies hold considerable promise for the treatment of cancer. The first approach seeks to activate tumor antigen-specific T lymphocytes while, the second, delays tumor growth by interfering with blood supply. Tumor Associated Antigens are often employed to target tumors with therapeutic drugs, but some are also essential for tumor viability. Survivin (Surv) is a member of the inhibitor of apoptosis protein family that is considered a Tumor Associated Antigen important for cancer cell viability and proliferation. On the other hand, Trypanosoma cruzi (the agent of Chagas’ disease) calreticulin (TcCRT) displays remarkable anti-angiogenic properties. Because these molecules are associated with different tumor targets, we reasoned that immunization with a Surv-encoding plasmid (pSurv) and concomitant TcCRT administration should generate a stronger anti-tumor response than application of either treatment separately. To evaluate this possibility, C57BL/6 mice were immunized with pSurv and challenged with an isogenic melanoma cell line that had been pre-incubated with recombinant TcCRT (rTcCRT). Following tumor cell inoculation, mice were injected with additional doses of rTcCRT. For the combined regimen we observed in mice that: i). Tumor growth was impaired, ii). Humoral anti-rTcCRT immunity was induced and, iii). In vitro rTcCRT bound to melanocytes, thereby promoting the incorporation of human C1q and subsequent macrophage phagocytosis of tumor cells. These observations are interpreted to reflect the consequence of the following sequence of events: rTcCRT anti-angiogenic activity leads to stress in tumor cells. Murine CRT is then translocated to the external membrane where, together with rTcCRT, complement C1 is captured, thus promoting tumor phagocytosis. Presentation of the Tumor Associated Antigen Surv induces the adaptive anti-tumor immunity and, independently, mediates anti-endothelial cell immunity leading to an important delay in tumor growth.     

Comparison of Three Dissolution Apparatuses for Testing Calcium Phosphate Pellets used as Ibuprofen Delivery Systems

Porous calcium phosphate pellets were produced according to two granulation processes (low and high shear wet granulations) and drug loaded with five ibuprofen contents (1.75%, 7%, 12.5%, 22%, and 36%) in order to ensure both bone defect filling and local drug delivery. The drug-release kinetics from the two types of pellets was studied using three dissolution apparatuses: paddle apparatus, reciprocating cylinder, and flow-through cell. The paper compared the three dissolution methods and considered the effect of the granulation process on the ibuprofen-release kinetics. Dissolution data were analyzed using the Weibull function as well as the difference (f1) and similarity (f2) factors. Dissolution kinetics was not influenced by the granulation process, regardless of the dissolution apparatus and of the drug content. The comparison of the three dissolution devices indicated that ibuprofen was released faster from granules loaded with 36% of drug content with the reciprocating apparatus, due to the disintegration of the granules occurring during the dissolution test. For the other drug contents, dissolution profiles were not significantly different from one apparatus to another. However, the flow-through cell seemed to be more suitable for the drug-release study of implantable materials.     

NINL and DZANK1 Co-function in Vesicle Transport and Are Essential for Photoreceptor Development in Zebrafish

Ciliopathies are Mendelian disorders caused by dysfunction of cilia, ubiquitous organelles involved in fluid propulsion (motile cilia) or signal transduction (primary cilia). Retinal dystrophy is a common phenotypic characteristic of ciliopathies since photoreceptor outer segments are specialized primary cilia. These ciliary structures heavily rely on intracellular minus-end directed transport of cargo, mediated at least in part by the cytoplasmic dynein 1 motor complex, for their formation, maintenance and function. Ninein-like protein (NINL) is known to associate with this motor complex and is an important interaction partner of the ciliopathy-associated proteins lebercilin, USH2A and CC2D2A. Here, we scrutinize the function of NINL with combined proteomic and zebrafish in vivo approaches. We identify Double Zinc Ribbon and Ankyrin Repeat domains 1 (DZANK1) as a novel interaction partner of NINL and show that loss of Ninl, Dzank1 or both synergistically leads to dysmorphic photoreceptor outer segments, accumulation of trans-Golgi-derived vesicles and mislocalization of Rhodopsin and Ush2a in zebrafish. In addition, retrograde melanosome transport is severely impaired in zebrafish lacking Ninl or Dzank1. We further demonstrate that NINL and DZANK1 are essential for intracellular dynein-based transport by associating with complementary subunits of the cytoplasmic dynein 1 motor complex, thus shedding light on the structure and stoichiometry of this important motor complex. Altogether, our results support a model in which the NINL-DZANK1 protein module is involved in the proper assembly and folding of the cytoplasmic dynein 1 motor complex in photoreceptor cells, a process essential for outer segment formation and function.     

Glycan-Dependent Immunogenicity of Recombinant Soluble Trimeric Hemagglutinin

Recombinant soluble trimeric influenza A virus (IAV) hemagglutinin (sHA₃) has proven an effective vaccine antigen against IAV. Here, we investigate to what extent the glycosylation status of the sHA₃ glycoprotein affects its immunogenicity. Different glycosylation forms of subtype H5 trimeric HA protein (sH5₃) were produced by expression in insect cells and different mammalian cells in the absence and presence of inhibitors of N-glycan-modifying enzymes or by enzymatic removal of the oligosaccharides. The following sH5₃ preparations were evaluated: (i) HA proteins carrying complex glycans produced in HEK293T cells; (ii) HA proteins carrying Man₉GlcNAc₂ moieties, expressed in HEK293T cells treated with kifunensine; (iii) HA proteins containing Man₅GlcNAc₂ moieties derived from HEK293S GnTI(−) cells; (iv) insect cell-produced HA proteins carrying paucimannosidic N-glycans; and (v) HEK293S GnTI(−) cell-produced HA proteins treated with endoglycosidase H, thus carrying side chains composed of only a single N-acetylglucosamine each. The different HA glycosylation states were confirmed by comparative electrophoretic analysis and by mass spectrometric analysis of released glycans. The immunogenicity of the HA preparations was studied in chickens and mice. The results demonstrate that HA proteins carrying terminal mannose moieties induce significantly lower hemagglutination inhibition antibody titers than HA proteins carrying complex glycans or single N-acetylglucosamine side chains. However, the glycosylation state of the HA proteins did not affect the breadth of the antibody response as measured by an HA1 antigen microarray. We conclude that the glycosylation state of recombinant antigens is a factor of significant importance when developing glycoprotein-based vaccines, such as recombinant HA proteins.     

Inequity aversion in relation to effort and relationship quality in long-tailed Macaques (Macaca fascicularis)

Social animals may employ evolved implicit rules to maintain a balance between cooperation and competition. Inequity aversion (IA), the aversive reaction to an unequal distribution of resources, is considered such a rule to avoid exploitation between cooperating individuals. Recent studies have revealed the presence of IA in several nonhuman species. In addition, it has been shown that an effort is crucial for this behavior to occur in animals. Moreover, IA may well depend on the partner's identity. Although dominant individuals typically monopolize food, subordinate individuals obtain less preferred food and usually do not protest. Furthermore, "friends" may pay less attention to equity than "nonfriends." We tested whether long-tailed macaques show IA with different cost-benefit ratios. In addition, we determined whether IA depends on relationship quality (RQ). Dominant subjects expressed IA only when a small effort was required. At a very large effort, however, long-tailed macaques did not show IA, possibly owing to bottom effects on the number of rewards they aim to receive. Moreover, and contrary to our predictions, an individual's inequity response was similar when tested with a "friend" or a "nonfriend." Therefore, we conclude that long-tailed macaques show IA only in conditions of moderate effort, yet that IA seems independent of RQ. Furthermore, IA may not be domain specific. Altogether, IA may be a trait present in all species that habitually cooperate, independent of their social organization.