Detection of cellular responses to toxicants by dielectrophoresis

The dielectrophoretic (DEP) crossover method has been applied to the detection of cell responses to toxicants. Time and dose responses of the human cultured leukemia (HL-60) line were measured for paraquat, styrene oxide (SO), N-nitroso-N-methylurea (NMU) and puromycin. These toxicants were chosen because of their different predominant mechanisms of action, namely membrane free radical attack, simultaneous membrane and nucleic acid attack, nucleic acid alkylation, and protein synthesis inhibition, respectively. For all treatments, the specific membrane capacitance (C_mem) of the cells decreased while the specific membrane conductance (G_mem) increased in dose- and time-dependent manners. The DEP responses correlated sensitively with alterations in cell surface morphology, especially folds, microvilli, and blebs, observed by scanning electron microscopy. The DEP method was more sensitive to agents that had a direct action on the membrane than to agents for which membrane alterations were secondary. The responses to paraquat and SO, which directly damaged the cell membrane, could be detected 15 min after exposure, while those for puromycin and NMU, which acted on intracellular targets, could be detected after 30 min. The detection times and dose sensitivity results showed that the DEP method is much faster and more sensitive than conventional cell and higher organism viability testing techniques. The feasibility of producing small instruments for toxicity detection and screening based on cellular dielectric responses is discussed.     

Morphological variability of Aulacoseira granulata (Ehr.) Simonsen (Bacillariophyceae) in the Lower Paraná River (Argentina)

In this paper we consider the morphological variation within a natural population of Aulacoseira granulata (Ehr.) Simonsen in relation to environmental factors. This species was dominant in the phytoplankton of the Lower Paraná River (Argentina) and exhibited seasonal fluctuations of cell dimensions. The mean cell diameter was directly correlated with the river water level and inversely with pH and nitrate concentrations, whereas cell length was directly correlated with transparency and nitrate concentration and inversely with suspended solids. This pattern was similar to that observed for filament length. The cell length : diameter ratio was inversely related to water level and discharge and directly related to pH, transparency, and nitrate concentration. Maximum diameters did not coincide with maximum lengths. A tendency to maintain cell volume throughout the annual cycle was observed, which probably relates to both buoyancy and photosynthetic capacity. These results associate the water ascendancy and the size recovery phases to discharge. Cells become smaller on the ebbing of the flood phase, and the decreasing depth increases the probability that the alga will be disentrained from the turbulent field. The loss during low water would act as a stimulus for auxosporulation, contributing to the production of large cells to start off the next population. Received: August 12, 2000 / Accepted: November 14, 2000     

The varied presentation of metastatic melanoma in fine needle aspiration cytology of the breast

D. L. Ribu, P. W. Shield and J. F. Bligh
The varied presentation of metastatic melanoma in fine needle aspiration cytology of the breast Objective: To identify cytomorphological patterns of metastatic melanoma (MM) in breast fine needle aspiration (FNA) specimens and highlight the differential diagnoses and features most useful in identifying MM. Methods: The clinical, radiological and FNA findings of 16 cases were reviewed. Cytological features evaluated related to cell arrangement, size and shape of cells, nuclear and cytoplasmic features, and the presence or absence of necrosis. Results: The series consisted of 14 females and two males, ranging in age from 24 to 83 years (mean = 50 years). A previous history of melanoma was available in 12/16 (75%) cases at the time of FNA reporting; however the clinical/radiological impression in 4/16 cases was of a breast cyst. The cases were classified into six morphological variants: classical (8/16), pseudopapillary (3/16), spindle‐cell (1/16), melanin‐rich (1/16), pleomorphic (2/16) and lymphoma‐like (1/16). The varying patterns raised a wide range of differential diagnoses; however, discohesion, binucleation and granular cytoplasm were the major features seen in 94% of all cases. In 14/16 cases (88%), plasmacytoid cells, prominent nucleoli and cytoplasmic vacuolation were identified. Melanin and multinucleation were detected in 44% of cases and intranuclear cytoplasmic invaginations in 63%. Necrosis was present in more than half of the cases (56%). Conclusion: MM should be considered in the differential diagnosis of breast FNA specimens when atypical cells are seen that present as plasmacytoid cells in a dispersed or pseudopapillary pattern, or as spindle, pleomorphic or pigmented cells. These features, combined with clinical history and immunocytochemistry, may assist in correctly identifying MM and directing optimal treatment.     

Root exudates from sunflower (Helianthus annuus L.) show a strong adsorption ability toward Cd(II)

Abstract

Cd(II) adsorption of root exudates from sunflower (Helianthus annuus L.) seedling was investigated by Cd ion-selective electrode, Fourier Transform Infrared spectroscopy, and fluorescence spectroscopy. Root exudates from Helianthus annuus L. had strong adsorption ability toward Cd(II). The adsorption process was pH-dependent and the maximum adsorption capacity, 150.8 mg g^?1, was observed at pH 7.0. Root exudates had pK _a1 at 4.7 for carboxyl and pK _a2 at 9.2 for phenolic, and amino groups. The aliphatic and aromatic (C?H) groups, amide III group, and the C (=O)?O and sulfonate groups were responsible for Cd(II) adsorption. The excitation emission matrix fluorescence spectroscopy showed protein-like substances participated in Cd adsorption and formed strong complexes, with conditional stability constants of 4.70 and 4.32, which is a little lower than that determined by potentiometric methods, 5.13. The strong Cd complexing ability of root exudates implies that root exudates may significantly affect mobility, toxicity, and phytoavailability of Cd. Cd binding of root exudates may be attributed to its interaction with the proteins, polysaccharides, and phenolic compounds in root exudates.     

Three new species of the leafhopper genus Tambocerus Zhang & Webb (Hemiptera,Cicadellidae) from southern China

Three new species, Tambocerus dentatus, T. longicaudatus and T. robustispinus spp. n. from southern China, are described and illustrated. A checklist and distribution to the Tambocerus species from China is provided together with a key for their separation.     

Elongated hindguts in desert‐living dung beetles (Scarabaeidae: Scarabaeinae) feeding on dry dung pellets or plant litter

Most adult dung beetles (Scarabaeidae: Scarabaeinae) feed on fresh, wet dung of larger herbivorous or omnivorous mammals. As refractory plant fragments are selected out before ingestion, the food is presumed easily digestible. However, members of the desert‐living scarabaeine genus Pachysoma (probably evolved from an ancestor closely related to the wet‐dung feeding genus Scarabaeus) select dry dung pellets and/or plant litter. Thus, they ingest a much higher proportion of structural plant material, which nevertheless appears to be digested rather efficiently. This study investigates morphological modifications of the gut for this digestion in adults of eight Pachysoma species, both pellet and litter feeders. To ascertain hypothesized ancestral conditions, four fresh‐dung feeding Scarabaeus species were also examined. The latter have the usual dung beetle gut consisting of a long, simple midgut, followed by an equally simple, much shorter hindgut of the same width. Lengths of midguts (M) and hindguts (H) divided by body length (B) for comparison between species of different size are: 4.9–6.3 (M/B) and 0.7–0.8 (H/B), which is normal for dung feeders. In Pachysoma, lengths are 6.3–6.5 (M/B) and 1.0–1.4 (H/B) in pellet feeders, and 4.4–5.0 (M/B) and 2.0–2.5 (H/B) for litter feeders. Hindguts are still morphologically undifferentiated and of midgut width, but clearly longer, particularly in litter feeders. Presumably, plant fragments in the food are digested, at least partly, in the hindgut. If so, the morphological adaptation is unusual: simple elongation rather than the expansion of part of the hindgut, as found in several other plant‐ or detritus‐feeding scarabaeids. J. Morphol. 2013. © 2013 Wiley Periodicals, Inc.     

Proteomic Analysis of Specific Proteins in the Root of Salt-Tolerant Barley

Comparative two-dimensional electrophoresis showed six proteins, which were significantly produced in the root of salt-tolerant barley. These proteins were identified as stress/defense-related proteins that do not scavenge reactive oxygen species directly, suggesting that salt-tolerant barley develops not only an antioxidative system, but also physical and biochemical changes to cope with salt stress.     

Fine needle aspiration biopsy of three cases of squamous cell carcinoma presenting as a thyroid mass: cytological findings and differential diagnosis

M. Rosa and K. Toronczyk Fine needle aspiration biopsy of three cases of squamous cell carcinoma presenting as a thyroid mass: cytological findings and differential diagnosis Objective: Primary squamous cell carcinomas of the thyroid gland are extremely rare, comprising about 1% of thyroid malignancies. Although squamous cell carcinomas are readily identified as such on aspiration cytology in the majority of cases, the differentiation of primary versus metastatic tumour might not always be easy. Herein, we report three cases of squamous cell carcinomas involving the thyroid gland. Methods: Fine needle aspiration cytology (FNAC) was performed in three patients with a thyroid mass using standard guidelines. Smears were stained with Diff‐Quik and Papanicolaou stains. Results: Two patients were male and one was female, aged 59, 45 and 35 years, respectively. In all three patients a thyroid mass was present. FNAC smears in all cases showed cytological features of squamous cell carcinoma including keratinization and necrosis. After clinical and cytological correlation, one case appeared to be primary, one case metastatic, and in the third case no additional clinical information or biopsy follow‐up was available for further characterization. Conclusions: Because primary squamous cell carcinoma of the thyroid is a rare finding, metastatic squamous cell carcinoma should always be excluded first. Metastatic disease usually presents in the setting of widespread malignancy, therefore a dedicated clinical and radiological investigation is necessary in these cases. In both clinical scenarios the patient’s prognosis is poor.     

Morphology of the first-instar nymph and adult female of Kermes echinatus Balachowsky,with a comparison to K. vermilio Planchon (Hemiptera,?Coccoidea,?Kermesidae)

Thefirst-instar nymph and the adult female of Kermes echinatus Balachowsky (Hemiptera, Coccoidea, Kermesidae) are described and illustrated. This species is compared with Kermes vermilio Planchon, a morphologically similar species known in the Palaeractic region.