Coronavirus and Paramyxovirus Shedding by Bats in a Cave and Buildings in Ethiopia

EcoHealth - Bats are important hosts of zoonotic viruses with pandemic potential, including filoviruses, MERS-Coronavirus (CoV), SARS-CoV -1, and likely SARS-CoV-2. Viral infection and transmission...     

Feeding and Refuge Use by Small Fish in the Presence of Cyanobacteria Blooms

We studied the effect of cyanobacteria on foraging and refuge use in small fish. We measured pike larval feeding in the presence of cyanobacteria by counting leftover prey. Our results showed that feeding by pike larvae on zooplankton prey decreased significantly in the presence of non-toxic cyanobacteria. The behaviour can be due to lowered vision caused by turbidity or clogging of the gills. Further, we tested whether the three-spined stickleback use toxic cyanobacteria as a refuge against predators in a choice experiment. The choice experiment was performed in a Y-maze fluviarum, where the fish could select between two different environments. Our results support the refuge use hypothesis because the three-spined stickleback clearly preferred toxic cyanobacteria to the chemical predator signal. To conclude, cyanobacteria decrease feeding rates in fish larvae, but may function as important refuge for e.g. sticklebacks, during predation pressure in pelagic algal blooms.     

Balancing algal toxicity and turbidity with predation risk in the three-spined stickleback

Prey may select suboptimal habitat to alleviate predation risk. Algal blooms and turbidity are potentially harmful to prey in aquatic environments, but can provide refugia against predation, given that predators avoid such conditions. Using a flow-through aquarium, we experimentally studied the habitat choice of the three-spined stickleback (Gasterosteus aculeatus L.) provided with toxic and non-toxic bloom-forming cyanobacteria and green flagellate-induced turbidity in the presence and absence of a chemical predator signal from a perch (Perca fluviatilis L.). We investigated whether sticklebacks separate between different algal strains and between turbid and clear water, and whether they are able to use algal toxicity and turbidity as shelter against predators. Sticklebacks preferred the toxic over the non-toxic Nodularia spumigena (Mertens) habitat in the presence of a predator signal, whereas no differences in times spent in the two habitats were detected when the predator signal was absent. There was a tendency for sticklebacks to prefer clear over turbid water in the absence of a predator signal, but no differences were found when the predator signal was present. Our results suggest that the three-spined stickleback is not fully adapted to the cyanobacterial blooms and turbidity caused by the recent eutrophication of the Baltic Sea. However, the predator-induced shifts in habitat choice are also consistent with the hypothesis that sticklebacks use algal toxicity and turbidity as shelters against predation, since these factors are likely to have only minor fitness consequences for sticklebacks.     

The involvement of mitochondria and the caspase-9 activation pathway in rituximab-induced apoptosis in FL cells

Despite the wide use of anti-CD20 antibody rituximab in the cancer treatment of B cell malignancies, the signalling pathways of CD20-induced apoptosis are still not understood. By using dominant negative (DN)-caspase-9 overexpressing follicular lymphoma cells we demonstrated that the activation of caspase-9 was essential for rituximab-mediated apoptosis. The death receptor pathway mediated by caspase-8 activation was not involved in rituximab-mediated apoptosis since overexpression of FLIP_short or FLIP_long proteins, inhibitors of caspase-8 activation, could not inhibit rituximab-induced apoptosis. However, the death receptor pathway activation by anti-Fas antibodies showed an additive effect on rituximab-induced apoptosis. The stabilisation of the mitochondrial outer membrane by Bcl-x_L overexpression inhibited cell death, showing the important role of mitochondria in rituximab-induced apoptosis. Interestingly, the rituximab-induced release of cytochrome c and collapse of mitochondrial membrane potential were regulated by caspase-9. We suggest that caspase-9 and downstream caspases may feed back to mitochondria to amplify mitochondrial disruption during intrinsic apoptosis.     

Drift-ice and under-ice water communities in the Gulf of Bothnia (Baltic Sea)

The algal, protozoan and metazoan communities within different drift-ice types (newly formed, pancake and rafted ice) and in under-ice water were studied in the Gulf of Bothnia in March 2006. In ice, diatoms together with unidentified flagellates dominated the algal biomass (226 ± 154 μg ww l⁻¹) and rotifers the metazoan and protozoan biomass (32 ± 25 μg ww l⁻¹). The under-ice water communities were dominated by flagellates and ciliates, which resulted in lower biomasses (97 ± 25 and 21 ± 14 μg ww l⁻¹, respectively). The under-ice water and newly formed ice separated from all other samples to their own cluster in hierarchical cluster analysis. The most important discriminating factors, according to discriminant analysis, were chlorophyll-a, phosphate and silicate. The under-ice water/newly formed ice cluster was characterized by high nutrient and low chlorophyll-a values, while the opposite held true for the ice cluster. Increasing trends in chlorophyll-a concentration and biomass were observed with increasing ice thickness. Within the thick ice columns (>40 cm), the highest chlorophyll-a concentrations (6.6–22.2 μg l⁻¹) were in the bottom layers indicating photoacclimation of the sympagic community. The ice algal biomass showed additional peaks in the centric diatom-dominated surface layers coinciding with the highest photosynthetic efficiencies [0.019–0.032 μg C (μg Chl-a ⁻¹ h⁻¹) (μE m⁻² s⁻¹)⁻¹] and maximum photosynthetic capacities [0.43-1.29 μg C (μg Chl-a ⁻¹ h⁻¹)]. Rafting and snow-ice formation, determined from thin sections and stable oxygen isotopic composition, strongly influenced the physical, chemical and biological properties of the ice. Snow-ice formation provided the surface layers with nutrients and possibly habitable space, which seemed to have favored centric diatoms in our study.     

Subjective symptoms among mobile phone users—A consequence of absorption of radiofrequency fields?

In a previous epidemiological study, where we studied the prevalence of subjective symptoms among mobile phone (MP) users, we found as an interesting side finding that the prevalence of many of the subjective symptoms increased with increasing calling time and number of calls per day. In this extrapolative study, we have selected 2402 people from the epidemiological study who used any of the four most common GSM MP. We used the information about the prevalence of symptoms, calling time per day, and number of calls per day and combined it with measurements of the Specific Absorption Rate (SAR). We defined three volumes in the head and measured the maximum SAR averaged over a cube of 1 g tissue (SAR(1g)) in each volume. Two new exposure parameters Specific Absorption per Day (SAD) and Specific Absorption per Call (SAC) have been devised and are obtained as combinations of SAR, calling time per day, and number of calls per day, respectively. The results indicates that SAR values >0.5 W/kg may be an important factor for the prevalence of some of the symptoms, especially in combination with long calling times per day.     

Antibodies to canine and feline viruses in spotted hyenas (Crocuta crocuta) in the Masai Mara National Reserve

Spotted hyenas (Crocuta crocuta) are abundant predators in the Serengeti ecosystem and interact with other species of wild carnivores and domestic animals in ways that could encourage disease transmission. Hyenas also have a unique hierarchical social system that might affect the flow of pathogens. Antibodies to canine distemper virus (CDV), feline immunodeficiency virus (FIV), feline panleukopenia virus/canine parvovirus (FPLV/CPV), feline coronavirus/ feline infectious peritonitis virus (FECV/IPV), feline calicivirus (FCV), and feline herpesvirus 1 (FHV1) have been detected in other Serengeti predators, indicating that these viruses are present in the ecosystem. The purpose of this study was to determine whether spotted hyenas also had been infected with these viruses and to assess risk factors for infection. Serum samples were collected between 1993 and 2001 from 119 animals in a single clan for which behavioral data on social structure were available and from 121 hyenas ill several other clans. All animals resided in the Masai Mara National Reserve. Antibodies to CDV, FIV, FPLV/CPV, FECV/FIPV, FCV, and FHV1 were present in 47%, 3.5%, 81%, 36%, 72%, and 0.5% of study hyenas, respectively. Antibody prevalence was greater in adults for FIV and FECV/FIPV, and being a female of high social rank was a risk factor for FIV. Hyenas near human habitation appeared to be at lower risk to have CDV, FIV, and FECV/FIPV antibodies, whereas being near human habitation increased the risk for FPLV/CPV antibodies. Canine (distemper virus and FECV/FIPV antibody prevalence varied considerably over time, whereas FIV, FPLV/CPV, and FCV had a stable, apparently endemic temporal pattern. These results indicate that hyenas might play a role in the ecology of these viruses in the Serengeti ecosystem. The effect of these viruses on hyena health should be further investigated. The lower prevalence of CDV antibody-positive hyenas near human habitation suggests that reservoirs for CDV other than domestic dogs are present in the Serengeti ecosystem.