Vanadyl bisacetylacetonate protects β cells from palmitate-induced cell death through the unfolded protein response pathway

Endoplasmic reticulum (ER) stress induced by free fatty acids (FFA) is important to β-cell loss during the development of type 2 diabetes. To test whether vanadium compounds could influence ER stress and the responses in their mechanism of antidiabetic effects, we investigated the effects and the mechanism of vanadyl bisacetylacetonate [VO(acac)₂] on β cells upon treatment with palmitate, a typical saturated FFA. The experimental results showed that VO(acac)₂ could enhance FFA-induced signaling pathways of unfolded protein responses by upregulating the prosurvival chaperone immunoglobulin heavy-chain binding protein/78-kDa glucose-regulated protein and downregulating the expression of apoptotic C/EBP homologous protein, and consequently the reduction of insulin synthesis. VO(acac)₂ also ameliorated FFA-disturbed Ca²⁺ homeostasis in β cells. Overall, VO(acac)₂ enhanced stress adaption, thus protecting β cells from palmitate-induced apoptosis. This study provides some new insights into the mechanisms of antidiabetic vanadium compounds.     

A novel zinc bis(thiosemicarbazone) complex for live cell imaging

Fluorescent zinc complexes have recently attracted a lot of interest owing to their vast applications in cellular imaging. We report the synthesis as well as physical, chemical and biological studies of a novel zinc glyoxalbis(4-methyl-4-phenyl-3-thiosemicarbazone), [Zn(GTSC)]₃, complex. As compared with the well-studied zinc biacetylbis(4-methyl-3-thiosemicarbazone), Zn(ATSM), complex, which was used as a reference, [Zn(GTSC)]₃ had 2.5-fold higher fluorescence. When cellular fluorescence was measured using flow cytometry, we observed that [Zn(GTSC)]₃ had 3.4-fold to 12-fold higher fluorescence than Zn(ATSM) in various cell lines (n = 9) of different tissue origin. Confocal fluorescence microscopy results showed that [Zn(GTSC)]₃ appeared to have a nuclear localization within 30 min of addition to MCF7 cells. Moreover, [Zn(GTSC)]₃ showed minimal cytotoxicity compared with Zn(ATSM), suggesting that [Zn(GTSC)]₃ may be less deleterious to cells when used as an imaging agent. Our data suggest that the novel [Zn(GTSC)]₃ complex can potentially serve as a biocompatible fluorescent imaging agent for live cells.     

Biodiversity and conservation of insects and other invertebrates

The thematic issue of Biodiversity and Conservation devoted to the biodiversity and conservation of insects and other invertebrates is introduced. The issue comprises 23 original research papers covering diverse habitats from forests to grasslands, ponds and rivers to coasts, and the tropics to boreal regions. Amongst the organisms discussed are ants, bees, beetles, butterflies, crabs, microgastropods, millipedes, spiders, and weevils. Some of the difficulties of conserving the most species-rich groups of eukaryotes, in the face of ignorance as to their identities and positions in ecological processes, are noted and the precautionary principle is seen as a pragmatic and responsible approach.     

Non-native and translocated fish species in Serbia and their impact on the native ichthyofauna

A total of 22 fish species have been introduced into the inland waters of Serbia, either intentionally or accidentally. This paper provides a summary of data concerning time and reason of introduction, mode of expansion, degree of acclimatization, impact on native fish and estimated area of recent distribution. Four of the non-native fish species currently occupy more than 51% of Serbian territory while 5 of them occupy between 21–50% of territory. This paper reviews impacts of introduced freshwater fish in Serbia based on collected data.     

Intestinal iron absorption during suckling in mammals

The maintenance of appropriate iron levels is important for mammalian health, particularly during the rapid growth period following birth. Too little iron can lead to irreversible damage to the developing central nervous system and too much iron at this point can have adverse long term consequences, possibly due to excessive free radical production. In order to maintain iron levels, intestinal iron absorption is very efficient in young mammals, such that almost all of the iron in breast milk is utilized. However this high level of absorption is unable to be down regulated in response to excess iron as it can be in adults, implying that different regulatory processes are involved during suckling. Various mechanisms have been proposed to explain this high absorption, including enhanced expression of the proteins involved in iron absorption in adults (particularly DMT1 and ferroportin), non-specific uptake via pinocytosis, and the uptake of lactoferrin bound iron by the lactoferrin receptor. However, at present the precise mechanism is unclear. It is possible that all of these components contribute to the high intestinal iron absorption seen during suckling, or a novel, as yet undescribed, mechanism could be involved. This review summarises the evidence for and against each of the mechanisms described above and highlights how little is known about iron homeostasis in this vital stage of development.     

<Emphasis Type=Italic>Pseudomonas</Emphasis> siderophores in the sputum of patients with cystic fibrosis

The lungs of patients with cystic fibrosis become chronically infected with the bacterium Pseudomonas aeruginosa, which heralds progressive lung damage and a decline in health. Iron is a crucial micronutrient for bacteria and its acquisition is a key factor in infection. P. aeruginosa can acquire this element by secreting pyoverdine and pyochelin, iron-chelating compounds (siderophores) that scavenge iron and deliver it to the bacteria. Siderophore-mediated iron uptake is generally considered a key factor in the ability of P. aeruginosa to cause infection. We have investigated the amounts of pyoverdine in 148 sputum samples from 36 cystic fibrosis patients (30 infected with P. aeruginosa and 6 as negative controls). Pyoverdine was present in 93 samples in concentrations between 0.30 and 51 μM (median 4.6 μM) and there was a strong association between the amount of pyoverdine and the number of P. aeruginosa present. However, pyoverdine was not present, or below the limits of detection (~0.3 μM), in 21 sputum samples that contained P. aeruginosa. Pyochelin was also absent, or below the limits of detection (~1 μM), in samples from P. aeruginosa-infected patients with little or no detectable pyoverdine. Our data show that pyoverdine is an important iron-scavenging molecule for P. aeruginosa in many cystic fibrosis patients, but other P. aeruginosa iron-uptake systems must be active in some patients to satisfy the bacterial need for iron.     

A macronutrient optimization platform for micropropagation and acclimatization: using turmeric (<Emphasis Type=Italic>Curcuma longa</Emphasis> L.) as a model plant

Tissue culture medium is often overlooked as a factor in plant biotechnology. Most work uses Murashige and Skoog (MS; Physiol Plant in 15:473–497, 1962) inorganic medium formulation, which is not likely optimal for many of the plant systems where it is used. This current study of macronutrient factors simultaneously altered media volume and amount of tissue (plants per vessel), sucrose, nitrogen (as NO₃⁻ and NH₄⁺ ions), and K⁺ in a d-optimal design space with only 55 experimental units (including five true replicates). Meso- and micro-nutrient concentrations were lowered (5% of MS) to determine which elements were most critical to plantlet quality. Plantlet quality was quantified by multiplication in the laboratory and survival and growth in the greenhouse. Plantlets grown at the lowest plant density, the lowest macronutrient concentration (20 mM), and equi-molar proportions of NH₄⁺/K⁺ resulted in the best multiplication ratio and 100% greenhouse survival. Multiplication ratio in vitro and survival in the greenhouse were well correlated with one another. Laboratory dry mass, media use, sucrose use, and the uptake of the macronutrients NO₃⁻, NH₄⁺, and K⁺ were not well correlated with plantlet quality. Plantlets with the greatest uptake of P, Ca, Mg, and Mn had the best multiplication in the laboratory and on subsequent transfer, acclimatized and grew fastest in the greenhouse. Phosphorus was shown to be most depleted in media. This work demonstrates a platform to simultaneously optimize several nutritive components of tissue culture media to produce plantlets that perform well in both laboratory and greenhouse environments. Plant quality was related with factors outside the macronutrient design, and this platform indicated where to expand the experimental space. Fixed, flat-screen presentations revealed less of the response surface than interactive profiles driven by the reader.     

Optimization of expression,purification, and NMR measurement for structural studies of transmembrane region of amyloid β protein

The amyloid precursor protein (APP) is an integral transmembrane protein which has been suggested to play a central role in the pathogenesis of Alzheimer’s disease. Despite the enormous amount of research conducted on amyloid protein, the precise mechanism of its toxic effect is not yet fully understood. To better understand the mechanism and function of amyloid protein, it is critical to elucidate the three-dimensional structure of the single transmembrane spanning region of human APP (hAPP-TM). Unfortunately, it is difficult to prepare the peptide sample because hAPP-TM is a membrane-bound protein that transverses the lipid bilayer of the cell membrane. Generally, the preparation of a transmembrane peptide is very difficult and time-consuming. In fact, high yield production of transmembrane peptides has been limited by experimental difficulties related to insufficient yields and the low solubility of such peptides. In this study, we describe experimental processes developed to optimize the expression, purification, and NMR measurement conditions for hAPP-TM transmembrane peptide.