Parastrombidinopsis shimi n. gen., n. sp. (Ciliophora: Choreotrichia) from the coastal waters of Korea: morphology and small subunit ribosomal DNA sequence

The planktonic ciliate Parastrombidinopsis shimi n. gen., n. sp. is described from both living cells and quantitative protargol-stained (QPS) preparations and the sequence of the small subunit rDNA (SSU rDNA) is reported. This species is almost oval when the cells are alive; when stained, it is cylindrical for the upper two-fifths, half-bowl shaped for the middle two-fifths, and narrow rodshaped for the lower one-fifth. The ranges (and mean +/- standard deviation, n = 20) of cell length, cell width, and oral diameter of living cells were 112-221 microm (168 +/- 39), 88-176 microm (121 +/- 30), and 53-110 microm (80 +/- 14), respectively, while those of the QPS-stained specimens (n = 54) were 88-225 microm (162 +/- 29), 55-163 microm (102 +/- 19), and 53-98 microm (69 +/- 9), respectively. Thirty-six to 48 external oral polykinetids had cilia 25-40 microm long. However, unlike Strombidinopsis species sensu stricto, P. shimi has an external oral polykinetid zone that is an open circle. This species has two shorter polykinetids associated with the end of the oral polykinetid zone, deep in the oral cavity. Like Strombidinopsis species in the subclass Choreotrichia, 36-50 somatic kineties were equally spaced around the cell body and extended from the oral to the posterior regions with 68-105 dikinetids per kinety. Both kinetosomes of each kinetid bore cilia 3-10 microm long. Parastrombidinopsis shimi had 2 (1-4) ovoid macronuclei of 20-82 x 15-32 microm. When properly aligned, the sequence of the SSU rDNA of P. shimi (GenBank Accession No. AJ786648) was approximately 5% different from that of Strobilidium caudatum and 6% different from that of two Strombidinopsis species. Based both on morphology and gene sequence divergence, we establish this is as a new species in a new genus belonging to the family Strombidinopsidae.     

Spectacular abundance of ciliates in anoxic pond water: contribution of symbiont photosynthesis to host respiratory oxygen requirements

Abstract: Very large numbers (3466 ml⁻¹) of ciliated protozoa were found living beneath the oxic-anoxic boundary in a stratified freshwater pond. Most ciliates (96%) contained symbiotic algae ( Chlorella spp.). Peak abundance was in anoxic water with almost 1 mol free CO₂ m⁻³ and a midday irradiance of 6 μmol photon m⁻² s⁻¹. Photosynthetic rate measurements of metalimnetic water indicated a light compensation point of 1.7 μmol photon m⁻² s⁻¹ which represents 0.6% of sub-surface light. We calculate that photosynthetic evolution of O₂ by symbionts is sufficient to meet the demand of the host ciliates for 13 to 14 hours each day. Each 'photosynthetic ciliate' may therefore become an aerobic island surrounded by anoxic water.     

The toxic effects of rubber contaminants on microbial food webs and zooplankton of two lakes of different trophic status

Rubber is commonly used in recreational equipment and devicesforsampling in lakes, but there have been few studies of theeffectsof rubber on planktonic organisms. We investigated the toxiceffects of rubber on the microbial food webs of a mesotrophiclakeand a eutrophic lake. Lake water was collected by pumping via,(i) a polyvinylchloride hose and, (ii) a rubber hose. Samplesoflake water collected by each method were incubated insitu in4.25 l enclosures for four days. The lake water was sampledbeforeand after incubation to determine the concentrations ofinorganicnutrients, chlorophyll a, microorganisms (bacteria,picophytoplankton, flagellates, ciliates) and zooplankton.In the mesotrophic lake, momentary exposure (ten seconds) oflakewater to the rubber hose significantly lowered theconcentrationsof chlorophyll a, bacteria, picophytoplankton and somespecies of zooplankton (Boeckella hamata, Bosmina,androtifers), relative to those in water exposed to the plastichose;flagellates, ciliates and Ceriodaphnia dubia were notsignificantly affected. In the eutrophic lake, the effects oftherubber hose on components of the microbial food web were muchlesssevere, and were consistent with the lake's high levels ofdissolved organic carbon (DOC), which is known to chelatetoxicmetals in water.     

Ixodid ticks (Acari: Ixodidae) infesting humans in Tokat Province of Turkey: species diversity and seasonal activity

Ixodid ticks (Acari: Ixodidae) are the major vectors of pathogens threatening animal and human health. Tokat Province, Turkey, is a suitable habitat for extended tick activity with its moderate climate and vegetation. In the present study, we surveyed humans visiting health centers to determine the species diversity, geographical distribution, and seasonal activity of ixodid ticks infesting them. Out of 5,999 adult ticks collected from humans from April to September, 2008, 800 ticks were identified to species, while the remaining were identified to genus according to their distinct morphological characteristics. Hyalomma marginatum, Hyalomma detritum, Rhipicephalus bursa, Rhipicephalus (Boophilus) annulatus, Haemaphysalis punctata, Dermacentor marginatus, and Ixodes laguri were the most prevalent tick species among 24 ixodid tick species infesting humans in the region. One of these tick species, Hyalomma isacii was identified as a new record for the ixodid tick fauna of Turkey. Hyalomma species were the most abundant in summer, while Dermacentor and Ixodes species displayed the lowest frequency. Hyalomma aegyptium infestation was very common on humans in the province. Results indicated that a variety of ixodid tick species infest humans depending on the season in the target area. It is possible that a variety of ixodid tick species may contribute to the spread of tick‐borne diseases such as Crimean‐Congo haemorrhagic fever virus (CCHFV), which is endemic in the region.     

A contribution to the Mesochorinae (Hymenoptera: Ichneumonidae) of Turkey

We present a first account of the species of the subfamily Mesochorinae (Hymenoptera: Ichneumonidae) found in Turkey and give distributional records for 5 genera and 23 species. Among them, 3 genera (Cidaphus Förster, 1869; Mesochorella Szepligeti, 1911; Stictopisthus Thomson, 1886) and 20 species are new for the fauna of Turkey.     

Contribution to the knowledge of the Ichneumonidae (Hymenoptera) fauna of Turkey

This study is based upon material of the family Ichneumonidae collected from Erzurum and Tunceli provinces of Turkey between 2011 and 2012. 64 species in 49 genera of the family Ichneumonidae were recorded. Among them, Alloplasta tomentosa (Gravenhorst, 1829), Lissonota (Lissonota) accusator (Fabricius, 1793), Dusona nidulator (Fabricius, 1804), Olesicampe fulviventris (Gmelin, 1790), Olesicampe proterva (Brischke, 1880), Olesicampe radiella (Thomson, 1885), Aptesis nigrocincta (Gravenhorst, 1815), Cryptus moschator (Fabricius, 1787), Pleolophus brachypterus (Gravenhorst, 1815), Hadrodactylus flavofacialis Horstmann, 2000, Lagarotis semicaligata (Gravenhorst, 1820), Coelichneumon (Coelichneumon) consimilis (Wesmael, 1845), Hoplismenus axillatorius (Thunberg, 1822) and Eridolius pictus (Gravenhorst, 1829) are new to the Turkish fauna. A short zoogeographic characterisation is given for each species.     

Effect of elevated atmospheric CO2 and vegetation type on microbiota associated with decomposing straw

Straw from wheat plants grown at ambient and elevated atmospheric CO₂ concentrations was placed in litterbags in a grass fallow field and a wheat field. The CO₂ treatment induced an increase in straw concentration of ash‐free dry mass from 84% to 93% and a decrease in nitrogen concentration from 0.43% to 0.34%. After five months of decomposition, less than 50% of the straw was decomposed. The content of ash‐free dry mass remaining in straw from plants grown at elevated CO₂ was significantly higher than that from plants grown at ambient CO₂ (4.02 vs. 3.69 g AFDM per litterbag in the fallow field and 3.40 vs. 2.67 g AFDM per litterbag when buried in the wheat field). The immobilization of nitrogen during decomposition was significantly higher in the ambient straw, and there was a significant negative correlation between the content of organic matter remaining per litterbag and the nitrogen concentration in the recovered straw samples. After five months of decomposition, hyphal biomass was significantly lower in straw from plants grown at elevated CO₂ (? 30% and ?13% in the fallow and wheat field, respectively). Bacterial biomass was not significantly affected by the CO₂ induced changes in the litter quality, but the lower decomposition rate and fewer bacterial grazers in the straw from plants grown at elevated CO₂ together indicate reduced microbial activity and turnover. Notwithstanding this, these data show that growth at elevated atmospheric CO₂ concentration results in slower decomposition of wheat straw, but the effect is probably of minor importance compared to the effect of varying crops, agricultural practise or changing land use.     

Biochemical and Cytological Evidence for an Overabundance of Mucocysts in the bcd Pattern Mutant of Tetrahymena thermophila

ABSTRACT. Three acidic proteins (42 kD, 43 kD and 50 kD) were present in unusually high concentrations in cortical preparations of the Tetrahymena pattern mutant broadened cortical domains (bcd). Antisera to the 42-kD and 50-kD proteins bound to discharging mucocysts and food vacuole contents in both wild-type and mutant cells. Subsequent analysis revealed that bcd mutant cell pellicles possess five times more docked mucocysts than their wild-type counterparts.     

Free-living amoebae and other neglected protistan pathogens: Health emergency signals?

Protistan parasites have an undisputed global health impact. However, outside of a few key exceptions, e.g. the agent of malaria, most of these infectious agents are neglected as important health threats. The Symposium entitled “Free-living amoebae and neglected pathogenic protozoa: health emergency signals?” held at the European Congress of Protistology in Rome, July 2019, brought together researchers addressing scientific and clinical questions about some of these fascinating organisms. Topics presented included the molecular basis of pathogenicity in Acanthamoeba; genomics of Naegleria fowleri; and epidemiology of poorly diagnosed enteric protistan species, including Giardia, Cryptosporidium, Blastocystis, Dientamoeba. The Symposium aim was to excite the audience about the opportunities and challenges of research in these underexplored organisms and to underline the public health implications of currently under-appreciated protistan infections. The major take home message is that any knowledge that we gain about these organisms will allow us to better address them, in terms of monitoring and treatment, as sources of future health emergencies.