Are coelenterate cells permeable to large anions?

• 1.1. Substitution of chloride by isethionate, a bulky anion, did not modify the intracellular cation or water content in cells of tentacles, and only slightly decreased sodium content in body wall cells of the coelenterate Condylactis gigantea, in contrast with the appreciable reductions expected in the case of impenneant anions.
• 2.2. As isethionic acid is a strong acid, the salt should be almost totally ionized at the pH of seawater (8.6) and at the presumably close to neutral intracellular pH. Therefore, the anion, rather than the undissociated acid, would appear to be the permeating species.
• 3.3. Isethionate ion appears to distribute across the cell membrane as does chloride: according to the transmembrane potential difference.

     

Are interstitial cells of Cajal plurifunction cells in the gut?

The proposed functions of the interstitial cells of Cajal (ICC) are to 1) pace the slow waves and regulate their propagation, 2) mediate enteric neuronal signals to smooth muscle cells, and 3) act as mechanosensors. In addition, impairments of ICC have been implicated in diverse motility disorders. This review critically examines the available evidence for these roles and offers alternate explanations. This review suggests the following: 1) The ICC may not pace the slow waves or help in their propagation. Instead, they may help in maintaining the gradient of resting membrane potential (RMP) through the thickness of the circular muscle layer, which stabilizes the slow waves and enhances their propagation. The impairment of ICC destabilizes the slow waves, resulting in attenuation of their amplitude and impaired propagation. 2) The one-way communication between the enteric neuronal varicosities and the smooth muscle cells occurs by volume transmission, rather than by wired transmission via the ICC. 3) There are fundamental limitations for the ICC to act as mechanosensors. 4) The ICC impair in numerous motility disorders. However, a cause-and-effect relationship between ICC impairment and motility dysfunction is not established. The ICC impair readily and transform to other cell types in response to alterations in their microenvironment, which have limited effects on motility function. Concurrent investigations of the alterations in slow-wave characteristics, excitation-contraction and excitation-inhibition couplings in smooth muscle cells, neurotransmitter synthesis and release in enteric neurons, and the impairment of the ICC are required to understand the etiologies of clinical motility disorders.     

Does insect herbivory on oak depend on the diversity of tree stands?

Studies on the effects of plant diversity on insect herbivory have produced conflicting results. Plant diversity has been reported to cause positive and negative responses of herbivores. Explanations for these conflicting responses include not only various population-level processes but also changes in plant quality that lead to changes in herbivore performance. In a tree diversity experiment, we investigated the effects of tree diversity on insect herbivory on oak in general and whether the effects of tree diversity on herbivore damage are reflected by the performance (leaf consumption, growth) of the generalist herbivore Lymantria dispar. Our study showed that the feeding damage caused by naturally occurring herbivores on oak trees decreased with increasing diversity of tree stands. The performance of L. dispar on oak leaves was not affected by tree diversity, neither in field nor laboratory experiments. Our results can be explained by the various processes behind the hypothesis of associational resistance.     

Long-term,large scale cryopreservation of insect cells at −80 °C

Standard tissue culture methods advise freezing cells in small aliquots (≤1 × 10⁷ cells in 1 mL), and storing in liquid nitrogen. This is inconvenient for laboratories culturing large quantities of insect cells for recombinant baculovirus expression, owing to the length of time taken to produce large scale cultures from small aliquots of cells. Liquid nitrogen storage requires use of specialized cryovials, personal protective equipment and oxygen monitoring systems. This paper describes the long-term, large scale cryopreservation of 8 × 10⁸ insect cells at −80 °C, using standard 50 mL conical tubes to contain a 40 mL cell suspension. Sf9, Sf21 and High 5 cells were recovered with a viability > 90 % after storage for one year under these conditions, which compared favorably with the viability of cells stored in liquid nitrogen for the same length of time. Addition of green fluorescent protein encoding baculovirus demonstrated that cells were “expression ready” immediately post thaw. Our method enables large scale cultures to be recovered rapidly from stocks cryopreserved at −80 °C, thus avoiding the inconvenience, hazards and expense associated with liquid nitrogen.

Electronic supplementary material

The online version of this article (doi:10.1007/s10616-014-9781-5) contains supplementary material, which is available to authorized users.     

Do small and large luteal cells of the sheep interact in the production of progesterone?

Corpora lutea from cyclic ewes were dissociated by collagenase and trypsin/EGTA treatments, and enriched fractions of small and large luteal cells were prepared on gradients of Ficoll. These fractions were incubated separately or remixed before incubation. Colchicine, cytochalasin B and the calcium channel-blocker verapamil significantly reduced progesterone production by both small and large luteal cell fractions, while isoprenaline stimulated an increase in progesterone production by large luteal cell fractions only. When fractions of small and large luteal cells were remixed, no more and no less progesterone was produced than would have been predicted from equivalent fractions incubated separately. There was therefore no evidence of synergism between small and large luteal cells in the production of progesterone. Prostaglandin F-2 alpha, which can inhibit LH-stimulated progesterone production by ovine luteal tissue in vitro, had no effect on LH-stimulated progesterone production by small luteal cell fractions, but significantly inhibited that by enriched fractions of large luteal cells. Since large luteal cell fractions were contaminated with small luteal cells, which are probably responsible for the progesterone-secretory response of these fractions to LH, it was concluded that the inhibition of LH-stimulated progesterone production by small luteal cells is dependent on the presence of large luteal cells. Oxytocin added to large and small luteal cell fractions did not affect progesterone production by either fraction. It was therefore concluded that the inhibitory action of PGF-2 alpha on LH-stimulated progesterone production may require the interaction of large and small luteal cells, but that oxytocin is not likely to be an intermediary in this interaction.     

Are plasmacytoid dendritic cells the misguided sentinels of malarial immunity?

Dendritic cells (DCs), the sentinels of immunity, reside in almost every organ of the body. These cells are responsible for initiating immune responses against infectious agents. DCs are divided into different subsets based on their biological functions, with plasmacytoid DCs (pDCs) and conventional DCs (cDCs) being two major populations. The ability of DCs to protect against malaria infection was recently questioned when pDCs were reported to be a reservoir for rodent Plasmodium spp. in the spleen. This opinion article explores how the occupation of pDCs by the parasite may corrupt immunity against malaria.     

Are the renin-containing granules of juxtaglomerular epithelioid cells modified lysosomes?

Summary Mature secretory granules of epithelioid cells — the so-called renin granules — exhibit certain properties, which in this particular combination are expressed only by lysosomes: Renin granules have autophagic capabilities; they react to the application of lipidosis-inducing, lysosomotropic substances by the gradual accumulation of polar lipids; all secretory granules of epithelioid cells contain acid phosphatase until maturity; and exogenous tracers reach renin granules without labeling the Golgi complex. Several functional implications can therefore be considered. Hydrolytic enzymes, constitutive elements of the granule matrix, might either cleave inactive prorenin to yield active renin within the granules or, by unspecific hydrolysis of renin, participate in the regulation of the overall quantity of secretory product. Autophagic phenomena, the involvement of renin granules in the traffic of exogenous tracers, and the build-up of polar lipids following experimental interference with lipid catabolism indicate a large turnover of membrane material in renin granules. They also suggest that cytoplasmic and extracellular fluid gains access to the granule content and may thus be involved there in the regulation of biochemical reactions by changing the intragranular milieu or via signal molecules.In addition to the lysosome-like properties of epithelioid cell secretory granules, the secretory product, renin, as a carboxyl protease, is structurally related to other acidic proteases. In the case of cathepsin D, even functional similarities exist.These studies were supported by the German Research Foundation within the SFB 90 Cardiovasculäres System.     

Are T cells at the origin of B cell lymphomas?

Lymphoma pathogenesis is at least in some cases related to transformed B cells (BCs) arising from germinal centre reactions (GCRs). In this article possible deregulations of GCRs are investigated using in silico simulations. It is found that the final differentiation of BCs as regulated by helper T cells (TCs) is the best candidate mechanism for such a deregulation. This shifts the paradigm of BC lymphoma pathogenesis from BC transformations to an emphasized role of TC-BC interactions.     

Are the Effects of Response Inhibition on Gambling Long-Lasting?

A recent study has shown that short-term training in response inhibition can make people more cautious for up to two hours when making decisions. However, the longevity of such training effects is unclear. In this study we tested whether training in the stop-signal paradigm reduces risky gambling when the training and gambling task are separated by 24 hours. Two independent experiments revealed that the aftereffects of stop-signal training are negligible after 24 hours. This was supported by Bayes factors that provided strong support for the null hypothesis. These findings indicate the need to better optimise the parameters of inhibition training to achieve clinical efficacy, potentially by strengthening automatic associations between specific stimuli and stopping.     

Observations on the effect of hurricane “Carla” on insect activity

Observations in the laboratory under conditions of controlled temperature and relative humidity on the effects of low barometric pressures on insect activity resulting fron hurricane Carla, one of the largest and most destructive hurricanes to affect the middle coast of Texas, revealed that stable flies (STOMOXYS CALCITRANS (L.)), house flies (MUSCA DOMESTICA L.), and Mexican fruit flies (ANASTREPHA LUDENS (Loew)), cockroaches (BLATELLA GERMANICA (L.)), PERIPLANETA AMERICANA (L.), and BLABERUS GIGANTEUS (L.) and mosquitoes (AEDES AEGYPTI (L.), exhibited nervous activity concomitant with the reduction in barometric pressure. Field studies throughout the critical storm period also indicated unusual arthropod activity. Following the hurricane, certain insect species emerged in abnormally large numbers, particularly fall armyworms (LAPHYGMA FRUGIPERDA (J.E. Smith)), asps (MEGALOPYGE OPERCULARIS (J. E. Smith)), and southern green stink bugs (NEZARA VIRIDULA (L.)).

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Zusammenfassung WÄhrend des Hurrikans Carla, einer der grössten und verheerendsten Orkane, die je auf die mittlere Küste von Texas eingewirkt haben, wurden im Laboratorium mit kontrollierter Temperatur und Feuchte, die Wirkungen von niedrigem Barometerdruck auf die InsektenaktivitÄt untersucht. Stallfliegen (STOMOXYS CALCITRANS (L.)), Hausfliegen (MUSCA DOMESTICA L.), Mexikanische Fruchtfliegen (ANASTREPHA LUDENS (Loew)), Schaben (BLATELLA GERMANICA L.), PERIPLANETA AMERICANA (L.) und BLABERUS GIGANTEUS (L.) und Mücken (AEDES AEGYPTI (L.)) zeigten wÄhrend der Verminderung des Barometerdruckes eine verstÄrkte AktivitÄt. Bei Studien im Freien wÄhrend der kritischen Orkanperiode wurde ebenfalls eine ungewöhnlich grosse AktivitÄt der Arthopoden beobachtet. Nach dem Orkan tauchten bestimmte Insektenarten in abnorm grosser Zahl auf. besonders (LAPHYGMA FRUGIPERDA (J.E.Schmith)), (MEGALOPYGE OPERCULARIS(J.E.Schmith)) und. (NEZARA VIRIDULA (L.)).

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Résumé L'effet, sur l'activité des insectes, des basses pressions barométriques résultant de l'ouragan Carla, un des plus vastes et des plus destructeurs qui aient affecté la cÔte moyenne du Texas, a été. observé au laboratoire dans des conditions de température et d'humidité relative constantes. Les mouches des étables (STOMOXYS CALCITRANS (L.)), les mouches domestiques (MUSCA DOMESTICA L.), les mouches à fruits mexicaines (ANASTREPHA LUDENS (Loew)), les cafards (BLATELLA GERMANICA (L.)), PERIPLANETA AMERICANA (L.) et BLABERUS GIGANTEUS (L.) et les moustiques (AEDES AEGYPTI (L.)) ont manifesté une activité accrue correspondant à la réduction de la pression barométrique. Des études faites en plein air pendant la période d'ouragan ont également permis d'observer chez les arthropodes une activité inaccoutumée. A la suite de l'ouragan sont apparus en quantités anormales certains insectes tels que le(LAPHYGMA FRUGIPERDA (J.E. Smith)), le (MEGALOPYGE OPERCULARIS (J.E.Smith)) et le (NEZARA VIRIDULA (L.)).

     

Is an intermediate state populated on the folding pathway of ubiquitin?

In the last couple of years, there has been increasing debate as to the presence and role of intermediate states on the folding pathways of several small proteins, including the 76-residue protein ubiquitin. Here, we present detailed kinetic studies to establish whether an intermediate state is ever populated during the folding of this protein. We show that the differences observed in previous studies are attributable to the transient aggregation of the protein during folding. Using a highly soluble construct of ubiquitin, which does not aggregate during folding, we establish the conditions in which an intermediate state is sufficiently stable to be observed by kinetic measurements.     

Does fecundity drive the evolution of insect diet?

We investigate whether egg load (a surrogate for fecundity) drives host specificity in a herbivorous insect. In many insects, including our study organism (Edith's checkerspot butterfly), both egg load and tendency to accept low-ranked hosts increase during each search for an oviposition site. Effects on host acceptance of egg load and passage of time are thereby potentially confounded. We conducted two experiments designed to disentangle these effects. In both experiments, we estimated the times of first acceptance of both a high-ranked and a low-ranked host, without allowing the insects to oviposit. In the first experiment, we measured egg load at the time of first acceptance of the low-ranked host. The later the time of first acceptance, the higher was the fecundity. We therefore reject the hypothesis that all insects accepted the low-ranked host at the same predetermined egg load. In the second experiment, we measured egg load 48 h after the high-ranked host was first accepted. We found no relationship between egg load and timing of acceptance of the low-ranked host. Insects with higher rates of egg accumulation did not accept the low-ranked host sooner. Taken together, these results suggest that acceptance of the low-ranked host is not driven directly by egg load. Rather, this acceptance results from some other process that is influenced by time since last oviposition. We conclude that there is no evidence to support the assumption that females with high rates of egg accumulation are more likely to accept low-ranked hosts.     

Are mesenchymal stromal cells immune cells?

Mesenchymal stromal cells (MSCs) are considered to be promising agents for the treatment of immunological disease. Although originally identified as precursor cells for mesenchymal lineages, in vitro studies have demonstrated that MSCs possess diverse immune regulatory capacities. Pre-clinical models have shown beneficial effects of MSCs in multiple immunological diseases and a number of phase 1/2 clinical trials carried out so far have reported signs of immune modulation after MSC infusion. These data indicate that MSCs play a central role in the immune response. This raises the academic question whether MSCs are immune cells or whether they are tissue precursor cells with immunoregulatory capacity. Correct understanding of the immunological properties and origin of MSCs will aid in the appropriate and safe use of the cells for clinical therapy. In this review the whole spectrum of immunological properties of MSCs is discussed with the aim of determining the position of MSCs in the immune system.     

Are T cells the only HIV-1 reservoir?

Current antiretroviral therapies have improved the duration and quality of life of people living with HIV-1. However, viral reservoirs impede complete eradication of the virus. Although there are many strategies to eliminate infectious virus, the most actively pursued are latency reversing agents in conjunction with immune modulation. This strategy, known as “shock and kill”, has been tested primarily against the most widely recognized HIV-1 latent reservoir found in resting memory CD4+ T cells. This is in part because of the dearth of conclusive evidence about the existence of non-T cell reservoirs. Studies of non-T cell reservoirs have been difficult to interpret because of technical and biological issues that have hampered a better understanding. This review considers the current knowledge of non-T cell reservoirs, the challenges encountered in a better understanding of these populations, and their implications for HIV-1 cure research.     

Are folliculo-stellate cells in the anterior pituitary gland supportive cells or organ-specific stem cells?

Folliculo-stellate cells (FS-cells) in the anterior pituitary gland are star-shaped cells and form tiny follicles. FS-cells are positive for S-100 protein and produce many cytokines or growth factors, such as interleukin-6 (IL-6), leukemia inhibitory factor (LIF), basic fibroblastic growth factor (bFGF) and vascular endothelial cell growth factor (VEGF). Therefore, it is generally accepted that FS-cells regulate endocrine cells through these growth factors. FS-cells also exhibit a phagocytotic activity and are known to work as scavenger cells. In addition to these functions, FS-cells are considered to have some unknown functions. In order to reveal the biological significance of FS-cells in the anterior pituitary gland, we performed a morphological study and obtained some new findings. First, we were interested in the colloid formation in the senescent porcine pituitary gland. We analyzed the colloids and found that clusterin is a major protein in them. We also found that the accumulation of clusterin in the colloids is related to the phagocytotic activity of FS-cells. In our next study, we found that FS-cells have the potential to differentiate into striated muscle cells. From FS-cells show multi-potent cell character and other cytological evidence, we propose that FS-cells are candidate of organ-specific stem cells in the anterior pituitary gland.     

Effect of Helicobacter pylori’s vacuolating cytotoxin on the autophagy pathway in gastric epithelial cells

Host cell responses to Helicobacter pylori infection are complex and incompletely understood. Here, we report that autophagy is induced within human-derived gastric epithelial cells (AGS) cells in response to H. pylori infection. These autophagosomes were distinct and different from the large vacuoles induced during H. pylori infection. Autophagosomes were detected by transmission electron microscopy, conversion of LC3-I to LC3-II, GFP-LC3 recruitment to autophagosomes, and depended on Atg5 and Atg12. The induction of autophagy depended on the vacuolating cytotoxin (VacA) and, moreover, VacA was sufficient to induce autophagosome formation. The channel forming activity of VacA was necessary for inducing autophagy. Intracellular VacA partially co-localized with GFP-LC3, indicating that the toxin associates with autophagosomes. The inhibition of autophagy increased the stability of intracellular VacA, which in turn resulted in enhanced toxin-mediated cellular vacuolation. These findings suggest that the induction of autophagy by VacA may represent a host mechanism to limit toxin-induced cellular damage.     

Are significant numbers of abnormal cells lost on the discarded ThinPrep® broom when used for cervical cytology?

A. Umana, H. Dunsmore, A. Herbert, A. Jokhan and A. Kubba
Are significant numbers of abnormal cells lost on the discarded ThinPrep® broom when used for cervical cytology? Background: In view of a study with SurePath® showing that cells were lost on the broom if it was discarded, we decided to investigate whether cells were lost on the ThinPrep® (TP) broom, which is discarded according to the manufacturer’s protocol. Aim: To determine whether significant amounts of cellular material are lost on the discarded TP broom, and whether the loss is operator dependent. Methods: Three hundred and six women attending the Guy’s Hospital Colposcopy Unit gave their consent for TP liquid‐based cytology samples to be taken and the broom immersed in a second vial instead of being discarded. The cellularity of the first and second vials was compared by counting cells in 10 ×40 high‐power fields (HPFs). The significance of cell loss was ascertained by correlating the likelihood of abnormal cells and transformation zone (TZ) material being present with the degree of cellularity of the two vials. Results: More than 10 cells per HPF were seen in 3.2%, 19.4% and 35.8% of slides from the second vial taken by three experienced colposcopists, which was significantly different between them (P < 0.001); cellularity of the first vial was not significantly different between colposcopists but the one with highest cellularity in the first vial discarded most in the second. Abnormal cells were more likely to be seen in slides with more than 10 cells per HPF (P < 0.001) and with evidence of TZ sampling (P < 0.001), but there was no preferential loss of TZ material in the second vial. Of 126 slides with abnormal cells on the slides from the second vial, 113 (89.7%) were also present on the significantly more cellular first vial (P < 0.001). Conclusion: Abnormal cells were potentially lost on the broom, but were usually represented in the first vial. The likelihood of abnormal cells being discarded was operator dependent in this small study, but this did not affect the quality of the initial preparation. The likelihood of abnormal cells being seen on TP slides was dependent on their cellularity, which provided our laboratory with a criterion for the assessment of sample adequacy.     

Are SCE frequencies indicative of adaptive response of plant cells?

Low-dose pretreatments with maleic hydrazide, mitomycin C, and N-methyl-N-nitrosourea or sublethal heat shock were tested with regard to their effect on sister-chromatid exchange (SCE) induction by high doses of the same mutagens administered 2 h later to root-tip meristems of Vicia faba. Consecutive treatments resulted in either additive or, in a minority of experiments, in below-additive SCE frequencies. A model is proposed to explain the conflicting data reported on adaptation to SCE and aberration induction.     

Effect of morroniside on glomerular mesangial cells through AGE–RAGE pathway

Diabetes mellitus is an endocrine and metabolic disease characterized by high blood glucose. Diabetic nephropathy (DN) is one of the most typical diabetic complications. Cornus officinalis is a type of traditional Chinese medicine that replenishes the liver and kidney. Morroniside is one of the main characteristic components of C. officinalis. In this study, an in vitro model for simulating DN damage was established by stimulating rat glomerular mesangial cells by the advanced glycation end products. The protective mechanism and effect of morroniside in regulating receptor for advanced glycation end products signaling pathway in DN was investigated to provide experimental evidence for the prevention and treatment of DN.