Language isolate

Summary

A language isolate is a language that has no demonstrable genetic relationship with another language. Basque in Europe, Ainu in Asia, Sandawe in Africa, Haida in North America, Kanoê in South America, and Tiwi in Australia are all examples of language isolates. The exact number of language isolates is yet unknown due to insufficient data on several languages. One explanation for the existence of language isolates is that they might be the last remaining branch of a larger language family. The language possibly had relatives in the past which have since disappeared without being documented. Another explanation for language isolates is that they developed in isolation from other languages. This explanation mostly applies to sign languages that have arisen independently of other spoken or signed languages. Some languages once seen as isolates may be reclassified as small families if some of their dialects are judged to be sufficiently different from t

Official source

https://en.wikipedia.org/wiki/Language_isolate

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Multidrug-resistant tuberculosis: household transmission and associated risk factors

Laurence Läser

Given the global burden of tuberculosis, and more precisely of multidrug-resistant (MDR) tuberculosis (TB), one of the most pressing epidemiological issues is the study and prevention of transmission. The study aims to assess transmission within households that present at least two cases of MDR-TB and the possible risk factors, from MDR-TB isolates collected in Lima, Peru and further characterized by genotyping methods, spoligotyping and mycobacterial interspersed repetitive units (MIRU) - variable number tandem repeat (VNTR), used for DNA fingerprinting. Apart from the genotyping results, the data set also provides the drug susceptibility testing (DST) profile for each isolate, as well as information on the households and the patients. The key assumption to transform molecular data into epidemiological data is that all identical isolates are classified in the same cluster, the cluster belong to a unique strain of tuberculosis, and a unique strain infecting more than one individual is presumed to be the result of direct transmission. The analysis is divided in two parts, first the establishment of household transmission or outside transmission for each isolate and then the following epidemiological analysis; and requires the use of Matlab and Stata software. The main results are the cohort characteristics, the concordance between the two genotyping methods, the clusters' composition and size frequency, the transmission analysis, the amplification of resistance analysis and the risk factors analysis for household transmission. From there, the main findings are the high rate of household transmission (more than 80%) of the isolates and drug resistance amplification (up to 10 new resisitances within one household clustered strain). The risk factor analysis did not present any significant results, but a few trends that are worth to explore in the future

2010

, ,

Enteroviruses are ubiquitous contaminants of surface waters, yet their fate in presence of microbial congeners is poorly understood. In this work, we investigated the inactivation of Echovirus-11 (E11) and Coxsackievirus-A9 (CVA9) by bacteria isolated from Lake Geneva. Incubation of E11 or CVA9 in biologically active lake water caused inactivation of 2- and 4-log10, respectively, within 48 h. To evaluate the antiviral action of individual bacterial species, we isolated 136 bacterial strains belonging to 31 genera from Lake Geneva. The majority of isolates (92) induced decay of at least 1.5-log10 of CVA9, whereas only 13 isolates induced a comparable inactivation on E11. The most extensive viral decay was induced by bacterial isolates producing matrix metalloproteases (MMPs). Correspondingly, the addition of a speciﬁc MMP inhibitor to lake water reduced the extent of inactivation for both viruses. A lesser, though signiﬁcant protective effect was also observed with inhibitors of chymotrypsin-like or trypsin-like proteases, suggesting involvement of serine proteases in enterovirus inactivation in natural systems. Overall, we demonstrate the direct effect of bacterial proteases on the inactivation of enteroviruses and identify MMPs as effective controls on enteroviruses’ environmental persistence.

2022

Expression in Yeast Links Field Polymorphisms in PfATP6 to in Vitro Artemisinin Resistance and Identifies New Inhibitor Classes

Serena Pulcini

Background. The mechanism of action of artemisinins against malaria is unclear, despite their widespread use in combination therapies and the emergence of resistance. Results. Here, we report expression of PfATP6 (a SERCA pump) in yeast and demonstrate its inhibition by artemisinins. Mutations in PfATP6 identified in field isolates (such as S769N) and in laboratory clones (such as L263E) decrease susceptibility to artemisinins, whereas they increase susceptibility to unrelated inhibitors such as cyclopiazonic acid. As predicted from the yeast model, Plasmodium falciparum with the L263E mutation is also more susceptible to cyclopiazonic acid. An inability to knockout parasite SERCA pumps provides genetic evidence that they are essential in asexual stages of development. Thaperoxides are a new class of potent antimalarial designed to act by inhibiting PfATP6. Results in yeast confirm this inhibition. Conclusions. The identification of inhibitors effective against mutated PfATP6 suggests ways in which artemisinin resistance may be overcome.

Oxford University Press2013