Failure to form antibodies following transfer of nucleoprotein fractions to chick embryos

В серии опытов, посвященных исследованиям роли нуклеопротеидов в процессе образования антител (Šterzl, Hrubešová 1955; Hrubešová, Askonas, Humphrey 1959; Šterzl, Hrubešová 1959; Hrubešová 1961) мы пользовались методом переноса фракций 3–5-дневным крольчатам. Для проверки результатов, полученных после переноса нуклеопротеидов, выделенных из селезенки взрослого кролика после его иммунизации одной дозой антигена Brucella suis (Hrubešová 1961), мы в настоящей работе в качестве реципиента применяли 18-дневные куриные эмбрионы, новорожденных цыплят и цыплят в возрасте 48 часов. Донорами клеток селезенки были взрослые куры, которых мы иммунизировали 1 мл антигена Brucella suis (7,5×10⁹ микробов), инактивированной протреванием за 24 или 48 час. до обескровливания. Приготовление и анализы нуклеопротеидов (РНП, ДНП) производились теми же методами, как и в предшествовавших работах. ДНК мы приготовляли по Schwander и Signer (1950), РНК—по Kirby (1956). После переноса ДНП, РНП, РНК и ДНК, выделенных через 24 и 48 час. после иммунизации взрослой курицы, нам не удавалось определить противобруцеллезные антитела в сыворотках реципиентов. Только в контрольном опыте переноса целых клеток селезенки, выделенных через 48 час. после иммунизации, мы находили антитела к Brucella suis с максимальным титром 1∶64. Обсуждается расхождение результатов при применении различных антигенов.      

Untersuchungen über die allelopathischen Eigenschaften der Getreidearten bei deren Nachkultivierung

In dieser Arbeit wurden allelopathische Eigenschaften von Roggen, Weizen, Gerste und Hafer studiert, die sich bei gegenseitigen Beziehungen dieser Getreidearten geltend machen können. Als Beweis für die Wurzelbeeinflussung der angeführten Getreidearten wurde eine Methode verwendet, bei der die erwähnten Getreidearten in derselben Kultivierungserde wuchsen, und zwar teils unmittelbar nacheinander, teils in abgestuften Zeitintervallen nacheinander mit verschiedenlanger Lagerungszeit der Erde. Die Versuchsergebnisse haben die Ansichten zahlreicher Verfasser bestätigt, die behaupten, dass die angegebenen Getreidearten allelopathish aktiv sind. Roggen, Weizen und Hafer beeinflussten signifikant das Wachstum der nachfolgenden Kulturen; dabei erwiesen die Ergebnisse nicht deutlich jene Beeinflussung, die durch das Erschöpfen der Nährstoffe durch die vorhergehende Pflanze bedingt worden wäre. Die angewandte Methode einer nachfolgenden Kultivierung erwies sich geeignet als Beweis für die allelopathischen Eigenschaften der Pflanzen unter natürlichen Bodenbedingungen. Die erwähnte Methode lässt sich vorteilhaft insbesondere in jenen Fällen anwenden, bei denen der Unterschied im Habitus der oberirdischen Teile der Pflanzenarten das Studium des Charakters ihrer gegenseitigen Beziehungen bei gemeinsamem Wachstum unmöglich macht. Diese Methode könnte ebenfalls eine Anwendung in der landwirtschaftlichen Praxis finden, wenn eine geeignete Zeitfolge der Pflanzen bei der unmittelbare Reihenfolge auf demselben Standort ermittelt werden soll.     

STIM1/ORAI1-mediated Ca2+ Influx Regulates Enolase-1 Exteriorization

Tumor cells use broad spectrum proteolytic activity of plasmin to invade tissue and form metastatic foci. Cell surface-associated enolase-1 (ENO-1) enhances plasmin formation and thus participates in the regulation of pericellular proteolysis. Although increased levels of cell surface bound ENO-1 have been described in different types of cancer, the molecular mechanism responsible for ENO-1 exteriorization remains elusive. In the present study, increased ENO-1 protein levels were found in ductal breast carcinoma and on the cell surface of highly metastatic breast cancer cell line MDA-MB-231. Elevated cell surface-associated ENO-1 expression correlated with augmented MDA-MB-231 cell migratory and invasive properties. Exposure of MDA-MB-231 cells to LPS potentiated translocation of ENO-1 to the cell surface and its release into the extracellular space in the form of exosomes. These effects were independent of de novo protein synthesis and did not require the classical endoplasmic reticulum/Golgi pathway. LPS-triggered ENO-1 exteriorization was suppressed by pretreatment of MDA-MB-231 cells with the Ca²⁺ chelator BAPTA or an inhibitor of endoplasmic reticulum Ca²⁺-ATPase pump, cyclopiazonic acid. In line with these observations, the stromal interaction molecule (STIM) 1 and the calcium release-activated calcium modulator (ORAI) 1-mediated store-operated Ca²⁺ entry were found to regulate LPS-induced ENO-1 exteriorization. Pharmacological blockage or knockdown of STIM1 or ORAI1 reduced ENO-1-dependent migration of MDA-MB-231 cells. Collectively, our results demonstrate the pivotal role of store-operated Ca²⁺ channel-mediated Ca²⁺ influx in the regulation of ENO-1 exteriorization and thus in the modulation of cancer cell migratory and invasive properties.     

A facile synthesis of d-ribo-C20-phytosphingosine and its C2 epimer from d-ribose

A facile synthetic route to d-ribo-C₂₀-phytosphingosine 31 and its C2 epimer 32 is described. The Overman rearrangement of allylic trichloroacetimidates derived from the known ribose derivative 7 has been used as the key step. The subsequent functional group interconversions in rearranged products 14 and 15 followed by Wittig olefination, Pd/C-mediated reduction and the removal of protecting groups successfully constructed the final molecules.     

Fluorescence spectroscopy studies of HEK293 cells expressing DOR-Gi1α fusion protein; the effect of cholesterol depletion

Biophysical studies of fluorescence anisotropy of DPH and Laurdan generalized polarization were performed in plasma membranes (PM) isolated from control and cholesterol-depleted HEK293 cells stably expressing pertussis toxin (PTX)-insensitive DOR-Gi1α (Cys351-Ile351) fusion protein. PM isolated from control, PTX-untreated, cells were compared with PM isolated from PTX-treated cells. Results from both types of PM indicated that i) hydrophobic membrane interior was made more accessible to water molecules and more chaotically organized in cholesterol-depleted samples, ii) cholesterol depletion resulted in an overall increase in surface area of membrane, membrane fluidity, and mobility of its constituents. Analysis of DOR-Gi1α coupling in PTX-treated and PTX-untreated cells indicated that cholesterol depletion did not alter the agonist binding site of DOR (Bmax and Kd) but the ability of DOR agonist DADLE to activate G proteins was markedly impaired. In PTX-untreated membranes, EC50 for DADLE-stimulated [35S]GTPγS binding was shifted by one order of magnitude to the right: from 4.3±1.2×10(-9) M to 2.2±1.3×10(-8) M in control and cholesterol-depleted membrane samples, respectively. In PTX-treated membranes, EC50 was shifted from 4.5±1.1×10(-9) M to 2.8±1.4×10(-8) M. In summary, the perturbation of optimum PM organization by cholesterol depletion deteriorates functional coupling of DOR to covalently bound Gi1α as well as endogenously expressed PTX-sensitive G proteins of Gi/Go family while receptor ligand binding site is unchanged. The biophysical state of hydrophobic plasma (cell) membrane interior should be regarded as regulatory factor of DOR-signaling cascade.     

Lipophilic Pt(II) complexes with selective efficacy against cisplatin-resistant testicular cancer cells

A series of dichloridoplatinum(II) complexes with selective and high cytotoxicity [IC₉₀(96 h) ≤ 3 μM] against cisplatin-resistant 1411HP testicular cancer cells were identified. They bear stationary 6-aminomethylnicotinate or 2,4-diaminobutyrate ligands esterified with lipophilic terpenyl residues, i.e., (−)/(+)-menthyl, (+)-cedrenyl, (−)-menthoxypropyl, or with a decyl-tethered 1,1,2-triphenylethene. They accumulated to a larger extent in 1411HP cells than in cells of the cisplatin-sensitive H12.1 germ cell tumour. Their mechanism of apoptosis induction differed from that of cisplatin by being independent of p53 and of caspase-3 activation and by an early loss of the mitochondrial membrane potential. The new complexes are promising candidates for the treatment of cisplatin-resistant testicular tumours.     

Brain to blood efflux as a mechanism underlying the neuroprotection mediated by rapid remote preconditioning in brain ischemia

Glutamate represents the main excitatory neurotransmitter in the mammalian brain; however, its excessive elevation in the extracellular space is cytotoxic and can result in neuronal death. The ischemia initiated brain damage reflects changes in glutamate concentration in peripheral blood. This paper investigated the role of the brain in blood efflux of the glutamate in an improved tolerance of the brain tissue to ischemic conditions. In the rat model of focal brain ischemia, the neuroprotection was initiated by rapid remote ischemic preconditioning (rRIPC). Our results confirmed a strong neuroprotective effect of rRIPC. We observed reduced infarction by about 78% related to improved neuronal survival by about 70% in the ischemic core. The level of tissue glutamate in core and penumbra dropped significantly and decreased to control value also in the core region of the contralateral hemisphere. Despite significant improvement of blood–brain barrier integrity (by about 76%), the additional gain of glutamate content in the peripheral blood was caused by rRIPC. Based on our results, we can assume that neuroprotection mediated by rapid remote ischemic preconditioning could lie in the regulated, whole-brain release of glutamate from nerve tissue to the blood, which preserves neurons from the exposure to glutamate toxicity and results in reduced infarction.