Freshwater crayfish invasions: former crayfish invader Galician crayfish hands title “invasive” over to new invader spiny-cheek crayfish

Biological invasions are a major threat to global biodiversity. Invasive freshwater crayfish in that context are especially prominent for their negative effects on both ecosystem integrity and native crayfish. However, some systems may have supported a crayfish species not originally native to the system without perceivable negative consequences for the ecosystem while other invasive crayfish species may constitute a major threat to ecosystem stability. Here I present an example how two crayfish, the spiny-cheek and the Galician crayfish both by researchers and governmental agencies considered non-native differ in their threats to the native ecosystem. Whereas the spiny-cheek crayfish is a recent potentially disease-transmitting and still spreading invader with high local densities the Galician crayfish might be part of the lake’s fauna since several hundred years, appears in lower densities and is unlikely to be a vector of disease. Therefore, regardless of the Galician crayfish’s actual date of introduction it is thus a rather “old and integrated” invader, which is now being faced and itself potentially threatened by the emergence of a “new and dangerous” invader: the spiny-cheek crayfish. This also exemplifies that in the face of often insufficient scientific information about dates of species introductions care should be taken in postulating species as invasive and dangerous without any form of risk assessment for their impact on the ecosystem.     

Actinomyces israelii endocarditis misidentified as “Diptheroids”

Actinomyces is a rare cause of endocarditis, however misidentification as Cornyebacteria often hampers the diagnosis.     

Cruciform extrusion propensity of human translocation-mediating palindromic AT-rich repeats

There is an emerging consensus that secondary structures of DNA have the potential for genomic instability. Palindromic AT-rich repeats (PATRRs) are a characteristic sequence identified at each breakpoint of the recurrent constitutional t(11;22) and t(17;22) translocations in humans, named PATRR22 (~600bp), PATRR11 (~450bp) and PATRR17 (~190bp). The secondary structure-forming propensity in vitro and the instability in vivo have been experimentally evaluated for various PATRRs that differ regarding their size and symmetry. At physiological ionic strength, a cruciform structure is most frequently observed for the symmetric PATRR22, less often for the symmetric PATRR11, but not for the other PATRRs. In wild-type E. coli, only these two PATRRs undergo extensive instability, consistent with the relatively high incidence of the t(11;22) in humans. The resultant deletions are putatively mediated by central cleavage by the structure-specific endonuclease SbcCD, indicating the possibility of a cruciform conformation in vivo. Insertion of a short spacer at the centre of the PATRR22 greatly reduces both its cruciform extrusion in vitro and instability in vivo. Taken together, cruciform extrusion propensity depends on the length and central symmetry of the PATRR, and is likely to determine the instability that leads to recurrent translocations in humans.     

Synthesis and evaluation of pyrazolo[3,4-b]pyridine CDK1 inhibitors as anti-tumor agents

A series of 3,5-disubstituted pyrazolo[3,4-b]pyridine cyclin-dependent kinase (CDK) inhibitors was synthesized. These compounds showed potent and selective CDK inhibitory activities and inhibited in vitro cellular proliferation in cultured human tumor cells. Selected compounds were evaluated in an in vivo tumor xenograft model. The synthesis and biological evaluation of these pyrazolo[3,4-b]pyridines and related compounds are reported.     

Design, synthesis, and evaluation of 3,4-disubstituted pyrazole analogues as anti-tumor CDK inhibitors

Two series of 3,4-disubstituted pyrazole analogues, 3-(benzimidazol-2-yl)-4-[2-(pyridin-3-yl)-vinyl]-pyrazoles (2) and 3-(imidazol-2-yl)-4-[2-(pyridin-3-yl)-vinyl]-pyrazoles (3), were synthesized as novel cyclin-dependent kinase (CDK) inhibitors. Representative compounds showed potent and selective CDK inhibitory activities and inhibited in vitro cellular proliferation in various human tumor cells. The design, synthesis, and preliminary biological evaluation of these pyrazole compounds are reported.     

Liver response of the Antarctic fish (<Emphasis Type="Italic">Notothenia coriiceps</Emphasis> Richardson, 1844) to hepatotrophic factors

The Notothenia coriiceps liver is commonly infected with parasites, reducing the hepatic mass and inducing the regeneration. In order to better understand the effect of nutrient influx on hepatic regeneration at 0°C, a usual mammal hepatotrophic factor (HF) solution was injected into ten fish (HF group), while ten fish were injected with saline solution (control), twice a day, for 15 days. The liver and carcass weight were measured, and samples were obtained for histological studies. The HF group presented a higher liver/carcass weight (62.5%) than control group. This increase in liver mass was due mainly to hepatocytes hypertrophy, including nuclear size increase and cytoplasmic inclusions of glycogen. Hyperplasia is also observed, although to a lesser extent. The hepatic reaction to HF in Antarctic fish was here demonstrated for the first time, helping to understand the liver response to seasonal nutrient.     

Synthesis of benzologues of Nitazoxanide and Tizoxanide: a comparative study of their in vitro broad-spectrum antiprotozoal activity

We have synthesized two new benzologues of Nitazoxanide (NIT) and Tizoxanide (TIZ), using a short synthetic route. Both compounds were tested in vitro against six protozoa (Giardia intestinalis, Trichomonas vaginalis, Entamoeba histolytica, Plasmodium berghei, Leishmania mexicana and Trypanosoma cruzi). Compound 1 (benzologue of NIT) showed broad antiprotozoal effect against all parasites tested, showing IC₅₀’s <5μM. This compound was five-times more active than NIT, and 18-times more potent than metronidazole against G. intestinalis. It was 10-times more active than pentamidine against L. mexicana, and it was sevenfold more potent than benznidazole versus T. cruzi. This compound could be considered as a new broad spectrum antiprotozoal agent.