A new species of Bradyidius (Copepoda, Calanoida) from the Gulf of Carpentaria, Australia

A new species of copepod belonging to the family Aetideidae,Bradyidius slyliformis sp. nov. is described and figured. Therelationship of this species to the other 12 members of thegenus is discussed. ¹Present address: 121 Jalan Athinahapan Dua, Taman Tun Dr Ismail,60000 Kuala Lumpur, Malaysia     

Activation of Ca2+ influx by metabolic substrates in Saccharomyces cerevisiae: role of membrane potential and cellular ATP levels

Influx of Ca2+ into cells of Saccharomyces cerevisiae was measured under non-steady-state conditions, which enable measurements of the initial rate of transport across plasma membranes without interference by the vacuolar Ca2+ transport system. Removal of glucose from the incubation medium led to inactivation of Ca2+ influx within 5 min. Readdition of glucose led to a transient increase in the rate of Ca2+ transport, reaching a peak after 3-5 min. A second increase was observed 60-80 min later. To examine whether the first transient activation of Ca2+ influx by glucose was mediated by membrane hyperpolarization, influx of 45Ca2+ was measured in the presence and absence of metabolic substrates (glucose, glycerol, and glucose plus antimycin A) in cells hyperpolarized to different values of membrane potential (delta psi). Logarithms of the rate of Ca2+ influx were plotted against values of delta psi. Two different slopes were obtained, depending upon whether the metabolic substrate was present or absent. Ca2+ influx in the presence of the metabolic substrates was always higher than expected by their effect on delta psi. Glycerol plus antimycin A did not affect Ca2+ influx. It was concluded that metabolized substrates activate Ca2+ influx not only by effects on delta psi but also by additional mechanism(s). Since no simple correlation between Ca2+ influx and intracellular ATP levels was observed, it was concluded that ATP levels do not affect the initial rates of Ca2+ transport across the plasma membrane of S. cerevisiae.     

Transient increase in Ca2+ influx in Saccharomyces cerevisiae in response to glucose: effects of intracellular acidification and cAMP levels

Influx of 45Ca2+ into Saccharomyces cerevisiae was measured under experimental conditions which enabled measurements of initial rate of transport across the plasma membrane, without interference by the vacuolar Ca2+ transport system. Addition of glucose or glycerol to the cells, after pre-incubation in glucose-free medium for 5 min, caused a rapid, transient increase in 45Ca2+ influx, reaching a peak at 3-5 min after addition of substrate. Ethanol, or glycerol added with antimycin A, had no effect on 45Ca2+ influx. We have shown previously that this increase is not mediated by an effect of the substrates on intracellular ATP levels. Changes in membrane potential accounted for only a part of the glucose-stimulated 45Ca2+ influx. The roles of intracellular acidification and changes in cellular cAMP in mediating the effects of glucose on 45Ca2+ influx were examined. After a short preincubation in glucose-free medium addition of glucose caused a decrease in the intracellular pH, [pH]i, which reached a minimum value after 3 min. A transient increase in the cellular cAMP level was also observed. Addition of glycerol also caused intracellular acidification, but ethanol or glycerol added with antimycin A had no effect on [pH]i. Artificial intracellular acidification induced by exposure to isobutyric acid or to CCCP caused a transient rise in Ca2+ influx but the extent of the increase was smaller than that caused by glucose, and the time-course was different. We conclude that intracellular acidification may be responsible for part of the glucose stimulation of Ca2+ influx.(ABSTRACT TRUNCATED AT 250 WORDS)     

Successful synthesis of a glial-specific blood–brain barrier shuttle peptide following a fragment condensation approach on a solid-phase resin

Successful manual synthesis of the TD2.2 peptide acting as a blood–brain barrier shuttle was achieved. TD2.2 was successfully synthesised by sequential condensation of four protected peptide fragments on solid-phase settings, after several unsuccessful attempts using the stepwise approach. These fragments were chosen to minimise the number of demanding amino acids (in terms of coupling, Fmoc removal) in each fragment that are expected to hamper the overall synthetic process. Thus, the hydrophobic amino acids as well as Arg(Pbf) were strategically spread over multiple fragments rather than having them congested in one fragment. This study shows how a peptide that shows big challenges in the synthesis using the common stepwise elongation methodology can be synthesised with an acceptable purity. It also emphasises that choosing the right fragment with certain amino acid constituents is key for a successful synthesis. It is worth highlighting that lower amounts of reagents were required to synthesise the final peptide with an identical purity to that obtained by the automatic synthesiser.     

Changes in the size of corpora allata,in the juvenile hormone III titer in the hemolymph,and in the protein content of terminal oocytes throughout the first gonadotropic cycle in Aiolopus thalassinus (Insecta: Orthoptera: Acrididae)

In Aiolopus thalassinus (Fabr.), the changes in the volume of the corpora allata (CA), in the concentration of juvenile hormone III (JH III) in the hemolymph, and in protein content in the terminal (t) oocytes were studied during the first gonadotropic cycle. These parameters could be better related to the volume of t-oocytes than to age after emergence. The JH III titer curve was maximum (2.9 pmol/10 μl) at an oocyte volume of 1.2 mm³. Before oviposition (days 10–16) the JH III titer decreased to 0.65 pmol/10 μl hemolyph. The increase in JH III titer reflected a period of high protein storage in the t-oocytes. The largest volume of the CA was reached at the beginning of yolk storage in the t-oocytes. The highest JH III titer did not correspond with the largest volume of CA, which occurred much earlier. © 1993 Wiley-Liss, Inc.     

Bacillus Species as Direct-Fed Microbial Antibiotic Alternatives for Monogastric Production

Probiotics and Antimicrobial Proteins - Antibiotic growth promoters have been utilized for long time at subtherapeutic levels as feed supplements in monogastric animal rations. Because of their...     

Description of Labidocera farrani sp. nov., a pontellid copepod known from eastern and northern Australian waters, (Crustacea, Copepoda)

Both sexes of a form previously recorded from Australian watersare described, and the species is named after its original discoverer.Features of the new species and of related species from thesuper-species detruncata, are tabulated and discussed.     

Identifying Metal Nanoparticle Size Effect on Sensing Common Human Plasma Protein by Counting the Sensitivity of Optical Absorption Spectra Damping

Colloidal nanoparticles (NPs) interact with biological fluids such as human plasma to form a protein coating (corona) on the surface of NPs (NP-protein complex). However, the impact of size and type of NPs on binding of the hard corona to the surface of NPs as well as damping of their optical spectra has not been systematically explored. To elucidate the interaction between biological environment (human plasma) and NPs, a photophysical measurement was conducted to quantify the interaction of two different types of NPs (gold (Au) and silver (Ag)) with common human plasma proteins. The colloidal AuNPs and AgNPs were electrostatically stabilized and varied in diameter from 10 to 80 nm in the presence of common human plasma. The sizes of the NPs were determined using transmission electron microscopy (TEM). Optical absorption spectra were obtained for the complexes. Dynamic light scattering (DLS) measurement and zeta potential were used to characterize the sizes, hydrodynamic diameters, and surface charges of the protein-NPs complexes. Protein separation was performed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to isolate and identify the protein bands. The absorption of proteins to the NPs was found to be strongly dependent on the size and type of NPs. The distance between surface of NPs by absorbed protein bound to the NPs gradually increased with size of NPs, particularly for AgNPs with primary diameter of < 50 nm. The chi-square test proved that AgNPs are a good candidate in sensing the protein complex in human plasma compared with AuNPs mainly for the AgNPs with diameter sized 50 nm.

     

Molecular docking analysis of HER-2 inhibitor from the ZINC database as anticancer agents

The human epidermal growth factor (HER2) is a transmembrane receptor that is highly expressed in breast cancer and in different other cancers. Therefore, it is of interest to identify the new HER2 inhibitors from a selected 300 compounds in the ZINC database. The top two hit compounds (ZINC000014780728 (-11.0 kcal/mol) and ZINC000014762512 (-10.8 kcal/mol)) showed a high affinity with HER2 relative to the reference compound (lapatinib (-10.2 kcal/mol)) for further consideration.