EUCAST and CLSI: Working Together Towards a Harmonized Method for Antifungal Susceptibility Testing

The U.S. Clinical and Laboratory Standards Institute (CLSI) and the European Committee of Antimicrobial Susceptibility Testing (AFST-EUCAST) have developed broth microdilution methodologies for testing yeasts and filamentous fungi (molds). The mission of these methodologies is to identify in vitro antifungal resistance, which is accomplished by the use of either clinical breakpoints (CBPs), or to a lesser degree, epidemiologic cutoff values (ECVs). The newly adjusted and species-specific CLSI CBPs for Candida spp. versus fluconazole and voriconazole have ameliorated some of the differences between the two methodologies. In the absence of CBPs for mold testing, CLSI ECVs are available for six Aspergillus species versus the triazoles, caspofungin and amphotericin B. Recently, breakpoints were developed by the EUCAST for certain Aspergillus spp. versus amphotercin B, itraconazole and posaconazole, which to some extent are comparable to ECVs. We summarize these latest accomplishments, which have made possible the harmonization of some susceptibility cutoffs, if not methodologies for some agent/species combinations.     

Evolutionary history of aphid-plant associations and their role in aphid diversification

Aphids are intimately linked with their host plants that constitute their only food resource and habitat, and thus impose considerable selective pressure on their evolution. It is therefore commonly assumed that host plants have greatly influenced the diversification of aphids. Here, we review what is known about the role of host plant association on aphid speciation by examining both macroevolutionary and population-level studies. Phylogenetic studies conducted at different taxonomic levels show that, as in many phytophagous insect groups, the radiation of angiosperms has probably favoured the major Tertiary diversification of aphids. These studies also highlight many aphid lineages constrained to sets of related host plants, suggesting strong evolutionary commitment in aphids’ host plant choice, but they fail to document cospeciation events between aphid and host lineages. Instead, phylogenies of several aphid genera reveal that divergence events are often accompanied by host shifts, and suggest, without constituting a formal demonstration, that aphid speciation could be a consequence of adaptation to new hosts. Experimental and field studies below the species level support reproductive isolation between host races as partly due to divergent selection by their host plants. Selected traits are mainly feeding performances and life cycle adaptations to plant phenology. Combined with behavioural preference for favourable host species, these divergent adaptations can induce pre- and post-zygotic barriers between host-specialized aphid populations. However, the hypothesis of host-driven speciation is seldom tested formally and must be weighed against overlooked explanations involving geographic isolation and non-ecological reproductive barriers in the process of speciation.     

Sequence and diversity of T-cell receptor alpha V, J, and C genes of the owl monkey Aotus nancymaae

 We cloned and sequenced TcR alpha chain cDNA of three healthy Aotus nancymaae monkeys. Fifteen different TRAJ segments and 9 different TRAV genes were identified in the 29 rearrangements analyzed. As expected from the greater phylogenetic distance, A. nancymaae TRA gene sequences diverged more from the human sequences than those of the chimpanzee or the rhesus macaque. However, no Aotus TRAJ segment or TRAV gene was found which lacked a human counterpart. These counterparts were AJ02, AJ05, AJ09, AJ15, AJ22, AJ23, AJ28, AJ30, AJ32, AJ34, AJ37, AJ40, AJ42, AJ45, AJ52 and AV2S1, AV2S3, AV3S1, AV8S1, AV12S1, AV15S1, ADV21S1/DV5, AV22S1S and AV23S1, respectively. In most cases the identity of amino acid sequences between corresponding Aotus and human genes was greater than 80%. This marked conservation of TRA gene sequences indicates a close structural relationship of Aotus and human TcR and demonstrates that the TcR repertoire in primates is remarkably stable. The results support the concept of using Aotus monkeys, which are susceptible to infection with the human malaria parasite Plasmodium falciparum, as an animal model for the evaluation of molecularly defined malaria vaccine candidates. Received: 15 January 1998 / Revised: 23 March 1998     

Increased high‐latitude photosynthetic carbon gain offset by respiration carbon loss during an anomalous warm winter to spring transition

Arctic and boreal ecosystems play an important role in the global carbon (C) budget, and whether they act as a future net C sink or source depends on climate and environmental change. Here, we used complementary in situ measurements, model simulations, and satellite observations to investigate the net carbon dioxide (CO₂) seasonal cycle and its climatic and environmental controls across Alaska and northwestern Canada during the anomalously warm winter to spring conditions of 2015 and 2016 (relative to 2010–2014). In the warm spring, we found that photosynthesis was enhanced more than respiration, leading to greater CO₂ uptake. However, photosynthetic enhancement from spring warming was partially offset by greater ecosystem respiration during the preceding anomalously warm winter, resulting in nearly neutral effects on the annual net CO₂ balance. Eddy covariance CO₂ flux measurements showed that air temperature has a primary influence on net CO₂ exchange in winter and spring, while soil moisture has a primary control on net CO₂ exchange in the fall. The net CO₂ exchange was generally more moisture limited in the boreal region than in the Arctic tundra. Our analysis indicates complex seasonal interactions of underlying C cycle processes in response to changing climate and hydrology that may not manifest in changes in net annual CO₂ exchange. Therefore, a better understanding of the seasonal response of C cycle processes may provide important insights for predicting future carbon–climate feedbacks and their consequences on atmospheric CO₂ dynamics in the northern high latitudes.     

Protecting capacity against malaria of chemically defined tetramer forms based on the Plasmodium falciparum apical sushi protein as potential vaccine components

Developing novel generations of subunit-based antimalarial vaccines in the form of chemically-defined macromolecule systems for multiple antigen presentation represents a classical problem in the field of vaccine development. Many efforts involving synthesis strategies leading to macromolecule constructs have been based on dendrimer-like systems, the condensation of large building blocks and conventional asymmetric double dimer constructs, all based on lysine cores.     

Analysis of the candidate tumor suppressor Ris-1 in primary human breast carcinomas

Frequent chromosome 3 losses have been described in several tumors types, which strongly suggest the presence of one or several tumor suppressor genes. Recently, a novel candidate tumor suppressor gene termed Ris-1 (for Ras-induced senescence 1) has been identified at chromosomal position 3p21.3. Ris-1 has been proposed to participate in anti-tumor responses that resemble cellular senescence and that are elicited by oncogenes such as Ras. To analyze the role of Ris-1 as a putative tumor suppressor gene in human breast cancer, we have performed a real-time quantitative analysis of its mRNA expression in 60 patients. Moreover, we carried out a first approach to evaluate the most common inactivation mechanism that can affect expression levels of tumor suppressor genes (mutation, promoter hypermethylation and allelic losses). Furthermore, a correlation study between expression as well as inactivating mechanisms of Ris-1 and several clinico-pathological parameters of the tumors was designed, with the objective of appraising the prognostic value of Ris-1 status. Decreased expression of Ris-1 was observed in 23% of the cases and overexpressed Ris-1 was detected in 15% of the primary breast tumors. Our data showed high frequency of LOH (30%) at one of the markers used. Nevertheless, a polymorphism related with the expression levels was described. Statistically significant correlations were found between decreased Ris-1 expression and negative progesterone receptors, as well as between overexpressing Ris-1 tumors and high histological grade. Despite all these data, we conclude that the suggested role of Ris-1 as tumor suppressor gene is not evident, at least in breast cancer. Future and larger series studies in different tumor types are necessary to clarify Ris-1 function in human cancer.     

Recombinant Candida rugosa LIP2 expression in Pichia pastoris under the control of the AOX1 promoter

The LIP2 isoenzyme gene from Candida rugosa has been completely synthesised and functionally expressed under the AOX1 promoter control in Pichia pastoris. The on-line monitoring and control of methanol, the key inducer carbon source in fed-batch cultures, has enhanced the yield product/biomass 7.8-fold and the productivity 12.8-fold compared to the best batch cultivation with the Pichia system and, 10-fold compared to the fed-batch cultivation process using the native C. rugosa strain.Nevertheless, the high ionic strength of culture broth favoured aggregation of Lip2, leading to total loss of lipolytic activity. After cultivation, a diaultrafiltration process was implemented to diminish ionic strength, allowing for the recovery of lipolytic activity in the diaultrafiltrate. The developed bioprocess resulted into a reproducible product in terms of quality and productivity.     

Basement membrane deposition of nidogen 1 but not nidogen 2 requires the nidogen binding module of the laminin gamma1 chain

The nidogen-laminin interaction is proposed to play a key role in basement membrane (BM) assembly. However, though there are similarities, the phenotypes in mice lacking nidogen 1 and 2 (nidogen double null) differ to those of mice lacking the nidogen binding module (γ1III4) of the laminin γ1 chain. This indicates different cell- and tissue-specific functions for nidogens and their interaction with laminin and poses the question of whether the phenotypes in nidogen double null mice are caused by the loss of the laminin-nidogen interaction or rather by other unknown nidogen functions. To investigate this, we analyzed BMs, in particular those in the skin of mice lacking the nidogen binding module. In contrast to nidogen double null mice, all skin BMs in γ1III4-deficient mice appeared normal. Furthermore, although nidogen 1 deposition was strongly reduced, nidogen 2 appeared unchanged. Mice with additional deletion of the laminin γ3 chain, which contains a γ1-like nidogen binding module, showed a further reduction of nidogen 1 in the dermoepidermal BM; however, this again did not affect nidogen 2. This demonstrates that in vivo only nidogen 1 deposition is critically dependent on the nidogen binding modules of the laminin γ1 and γ3 chains, whereas nidogen 2 is independently recruited either by binding to an alternative site on laminin or to other BM proteins.     

Hematologic and plasma biochemical reference intervals for Morelet's crocodiles (Crocodylus moreletii) in the northern wetlands of Campeche, Mexico

Health surveys and hematologic and plasma biochemical analyses were conducted in 52 free-ranging and 51 captive Morelet's crocodiles (Crocodylus moreletii) in Campeche, Mexico, March-September 2007. Blood samples from 92 crocodiles (45 free-ranging and 47 captive) were collected for hematologic and plasma biochemical analyses. Average values of erythrocytes of free-ranging crocodiles were 1,046,166 cells/μl, and total white cells were 1.03 × 10(4) cells/μl. Captive crocodiles had erythrocyte and leukocyte values of 1,100,416 cells/μl and 8.51 × 10(3) cells/μl, respectively. There were no significant differences in values of erythrocytes or in hematocrit between free-ranging and captive crocodiles, or between sexes, or among size classes. Counts of leukocytes in free-ranging crocodiles were significantly higher than in captive individuals. The mean values of plasma analytes were 69.55 mg/l (glucose), 250.14 mg/l (cholesterol), 3.04 mg/l (uric acid), 2.70 mg/l (creatinine), and 20.20 IU/l (alanine aminotransferase). There were significant differences in cholesterol between free-ranging and captive crocodiles and between sexes.     

Strophe Length in Spontaneous Songs Predicts Male Response to Playback in the Hoopoe Upupa epops

Hoopoe (Upupa epops, Coraciformes) males produce a very simple song during the breeding season in order to attract females and repel intruders. Strophes vary in length (i.e. number of elements) both within and between males, and previous studies have shown that this song cue is positively correlated with male condition and breeding success. In the present study we tested whether strophe length of males influences male behaviour during intra‐sexual contests, in a colour‐ringed population in southeast Spain. Paired males were presented with a recorded song with long strophes during the pre‐laying period, while they were near their mates, in order to provoke male mate‐defence behaviour. Most males responded to the playback, but the strategy of defence adopted depended on their own strophe length in spontaneous songs recorded before the experiments. While singing responses were common to most of the males, only those using long strophes adopted the most risky strategy of approaching the loudspeaker. However, the males that approached produced abnormal songs during playback, that were shorter and with fewer strophes than those of males that did not approach, and used shorter strophes in comparison with spontaneous songs before the experiment. These differences in quality of the song produced in response to the playback suggest that long‐strophe males were basing their response mainly on attacking rather than singing, while short‐strophe males tried to resolve the contest at a distance by means of their song. These results show that strophe length reflects some component of the competitive ability of males (either physical strength or aggressiveness) in the hoopoe, which together with previous results regarding its role for female choice, show that it is a sexual signal with dual function.