Analysis of the type material of Gomphosphenia tackei (Bacillariophyceae) and comparison to epizoic diatom populations on freshwater snails

Background and aims – Hustedt (1942) originally described Gomphosphenia tackei from Germany under the name Gomphonema tackei. Because of the small cell size and the lack of scanning electron microscopy (SEM) images from the type material, it is often confused with other species from this genus, especially with G. stoermeri. The aim of this paper was to present detailed morphological characteristics of G. tackei based on the analysis of the type material and of several epizoic populations from Central Europe. Material and methods – The material in this study was collected from the shells of the freshwater snails Lymnaea stagnalis, Planorbarius corneus, and Planorbis planorbis. Additionally, for an unambiguous species identification, the type material for Gomphosphenia tackei was analyzed using light and scanning electron microscopes.Key results – The presence of Gomphosphenia tackei was confirmed in the studied material. The largest population (up to 19%) was recorded on the shell surfaces of living snails, whereas on empty shells, the diatom did not seem to be present or only in very low numbers. Valves are typically clavate with rounded apices. Valves are frequently observed in girdle view, often joint together in pairs. The valves in the studied populations had a valve length of 7–29 µm, a valve width of 3–4 µm, and a stria density of 25–29 striae in 10 µm. In the type population, valve length ranged from 7.5 to 27 µm with a valve width of 3.0–4.0 µm and a stria density of 23–29 striae per 10 µm. Striae were composed of 2–4 elongated to rounded areolae per stria. At the apices, the striae were composed of one single areola. The cells were attached to the substratum by their footpole.Conclusion – Published illustrations of Gomphosphenia tackei do not always correctly represent this species. Individual cells are attached to the substratum by secreted mucilage, probably via their areolae or girdle band pores located on the footpole.

Small Cell Size Circulating Aneuploid Cells as a Biomarker of Prognosis in Resectable Non-Small Cell Lung Cancer

ObjectiveThe size distribution of circulating aneuploid cells (CACs) and its clinical significance were investigated in resectable non-small cell lung cancer (NSCLC).Patients and MethodsA total of 50 patients with resectable NSCLC were enrolled in this study. Blood samples (50 pre-surgery and 35 post-surgery) were collected and used for the detection of CAC chromosome 8 heteroploidy through the subtraction enrichment and immunostaining fluorescence in situ hybridization (SE-iFISH) method.ResultsLess than 20% small cell size and more than 80% large cell size CACs were detected. Karyotypes, including triploid, tetraploid, and multiploid, had varying distributions. The triploid subtype accounted for the majority of small cell size CACs, whereas the multiploid subtype accounted for the majority of large cell size CACs. We found that total small cell size and triploid small cell size CACs, but not large cell size CACs, derived from pre-surgery samples, were associated with shorter disease-free survival. Moreover, total small cell size and triploid small cell size CACs were associated with higher TNM stage and recurrence. Nevertheless, the variation between pre- and post-surgery CACs was not related to survival among patients with resectable NSCLC.ConclusionsPre-surgery small cell size CACs, especially the triploid subtype, could be regarded as a potential prognostic biomarker for patients with resectable NSCLC.

Presence of a resident species aids invader evolution

Phytoplankton populations are intrinsically large and genetically variable, and interactions between species in these populations shape their physiological and evolutionary responses. Yet, evolutionary responses of microbial organisms in novel environments are investigated almost exclusively through the lens of species colonising new environments on their own, and invasion studies are often of short duration. Although exceptions exist, neither type of study usually measures ecologically relevant traits beyond growth rates. Here, we experimentally evolved populations of fresh- and seawater phytoplankton as monocultures (the green algae Chlamydomonas moewusii and Ostreococcus tauri, each colonising a novel, unoccupied salinity) and co-cultures (invading a novel salinity occupied by a resident species) for 200 generations. Colonisers and invaders differed in extinction risks, phenotypes (e.g. size, primary production rates) and strength of local adaptation: invaders had systematically lower extinction rates and broader salinity and temperature preferences than colonisers – regardless of the environment that the invader originated from. We emphasise that the presence of a locally adapted species has the potential to alter the invading species’ eco-evolutionary trajectories in a replicable way across environments of differing quality, and that the evolution of small cell size and high ROS tolerance may explain high invader fitness. To predict phytoplankton responses in a changing world, such interspecific relationships need to be accounted for.

Reprogramming progressive cells display low CAG promoter activity

There is wide variability in the propensity of somatic cells to reprogram into pluripotency in response to the Yamanaka factors. How to segregate these variability to enrich for cells of specific traits that reprogram efficiently remains challenging. Here we report that the variability in reprogramming propensity is associated with the activity of the MKL1/SRF transcription factor and concurs with small cell size as well as rapid cell cycle. Reprogramming progressive cells can be prospectively identified by their low activity of a widely used synthetic promoter, CAG. CAGlow cells arise and expand during cell cycle acceleration in the early reprogramming culture of both mouse and human fibroblasts. Our work illustrate a molecular scenario underlying the distinct reprogramming propensities and demonstrate a convenient practical approach for their enrichment.

Prediction of neoadjuvant chemotherapeutic efficacy by CTC and cfDNA in patients with locally advanced breast cancer.

551 Background: Neoadjuvant chemotherapy (NCT) is the standard treatment for patients with locally advanced breast cancer (LABC). Liquid biopsy, including circulating tumor cells (CTCs) and cell free DNA (cfDNA) represent an important paradigm shift in precision medicine. The aim of this study was to estimate the value of CTCs and cfDNA in efficacy prediction of the response to NCT in patients with LABC. Methods: Patients with LABC received EC4-T4 regimen NCT. CTCs and cfDNA obtained at time of biopsy, after first course of NCT and after the last course of NCT. All patients were divided into two groups according to pathological reactivity. A novel SE-iFISH strategy, improved for detection of CTCs, was applied. CTCs(CD45-/CD31-) with different cytogenetic abnormality of aneuploid chromosome 8 and small cell size CTCs (≤5 mm of WBCs) were analyzed separately in LABC patients subjected to NCT for the first time. Plasma DNA biomarkers ALU 111 and ALU 260 elements were evaluated using qRT-PCR. DNA integrity was calculated relative to the breast cancer cell line MCF-7. Clinical significance of diverse subtypes of CTCs and cfDNA was systematically investigated. Results: A total of 45 patients was enrolled in this study. According to the therapy response, 6/45 patients had high response (High-R) and 39/45 patients had low response (Low-R). There were no significant differences in CTC number and small cell size CTC number between High-R and Low-R groups in all three detections. However, the CTC number kept stable in the High-R group, but increased continually during NCT in Low-R group. In 45 patients, the percentage of CTCs with trisomy 8, which were related to cancer metastasis, incresed in the Low-R group at the third dectection. The concentration of cfDNA in all three detections did not indicate outcome of NCT. However, concentration of ALU 111 increased in Low-R patients during NCT. In High-R patients, no significant increase was observed. A CTC and cfDNA panel were constructed to discriminate High-R patients from Low-R patients. The areas under the receiver-operating characteristic (ROC) curves of the pannel for the three times were 0.803, 0.859 and 0.667, respectively. DNA integrity index(CFDI) was significantly higher in High-R group than Low-R after first course of NCT. The areas under the ROC curves of the CFDI for the three times were 0.675, 0.863 and 0.697, respectively. Conclusions: The trend of cfDNA concentration changed resembled to the number of CTCs, small cell size CTCs and triploid CTCs during NCT, and could predict tumor response to ongoing treatment.

A Review of Automated Microinjection of Zebrafish Embryos

Cell microinjection is a technique of precise delivery of substances into cells and is widely used for studying cell transfection, signaling pathways, and organelle functions. Microinjection of the embryos of zebrafish, the third most important animal model, has become a very useful technique in bioscience. However, factors such as the small cell size, high cell deformation tendency, and transparent zebrafish embryo membrane make the microinjection process difficult. Furthermore, this process has strict, specific requirements, such as chorion softening, avoiding contacting the first polar body, and high-precision detection. Therefore, highly accurate control and detection platforms are critical for achieving the automated microinjection of zebrafish embryos. This article reviews the latest technologies and methods used in the automated microinjection of zebrafish embryos and provides a detailed description of the current developments and applications of robotic microinjection systems. The review covers key areas related to automated embryo injection, including cell searching and location, cell position and posture adjustment, microscopic visual servoing control, sensors, actuators, puncturing mechanisms, and microinjection.

First record and ecologic aspects of Isthmochloron neustonica Zalocar & Pizzarro (Tribophyceae) in São Paulo State, Brazil

ABSTRACT We present the morphometric characteristics of Isthmochloron neustonica populations as well as their abundance and the relationship with some environmental characteristics in a fishpond. This is the first record of the species in São Paulo State and second citation to Brazil. Isthmochloron neustonica was described in neustonic habit; in this study, with sampling for phytoplankton analysis, it was found in high density and short duration blooming (time interval up to 15 days). It represented 59% of total phytoplankton density on May 26, 2010, forming a delicate and bright film on the water surface, in an environment with high concentration of nutrients and associated with drought and low temperature. The species has a restricted range in South America, probably due to their biological characteristics, such as small cell size and neustonic habit. Few records in literature can also be one of the reasons that hampers the identification of the species in subtropical environments.

New high order FDTD method to solve EMC problems

In electromagnetic compatibility (EMC) context, we are interested in developing new ac- curate methods to solve efficiently and accurately Maxwell’s equations in the time domain. Indeed, usual methods such as FDTD or FVTD present im- portant dissipative and/or dispersive errors which prevent to obtain a good numerical approximation of the physical solution for a given industrial scene unless we use a mesh with a very small cell size. To avoid this problem, schemes like the Discontinuous Galerkin (DG) method, based on higher order spa- tial approximations, have been introduced and stud- ied on unstructured meshes. However the cost of this kind of method can become prohibitive accord- ing to the mesh used. In this paper, we first present a higher order spatial approximation method on carte- sian meshes. It is based on a finite element ap- proach and recovers at the order 1 the well-known Yee’s schema. Next, to deal with EMC problem, a non-oriented thin wire formalism is proposed for this method. Finally, several examples are given to present the benefits of this new method by compar- ison with both Yee’s schema and DG approaches.