'Mother(Nature) knows best' - hijacking nature-designed transcriptional programs for enhancing stress resistance and protein production in Yarrowia lipolytica; presentation of YaliFunTome database

BACKGROUND

In the era of rationally designed synthetic biology, heterologous metabolites production, and other counter-nature engineering of cellular metabolism, we took a step back and recalled that 'Mother(-Nature) knows best'. While still aiming at synthetic, non-natural outcomes of generating an 'over-production phenotype' we dug into the pre-designed transcriptional programs evolved in our host organism-Yarrowia lipolytica, hoping that some of these fine-tuned orchestrated programs could be hijacked and used. Having an interest in the practical outcomes of the research, we targeted industrially-relevant functionalities-stress resistance and enhanced synthesis of proteins, and gauged them over extensive experimental design's completion.

RESULTS

Technically, the problem was addressed by screening a broad library of over 120 Y. lipolytica strains under 72 combinations of variables through a carefully pre-optimized high-throughput cultivation protocol, which enabled actual phenotype development. The abundance of the transcription program elicitors-transcription factors (TFs), was secured by their overexpression, while challenging the strains with the multitude of conditions was inflicted to impact their activation stratus. The data were subjected to mathematical modeling to increase their informativeness. The amount of the gathered data prompted us to present them in the form of a searchable catalog - the YaliFunTome database ( https://sparrow.up.poznan.pl/tsdatabase/ )-to facilitate the withdrawal of biological sense from numerical data. We succeeded in the identification of TFs that act as omni-boosters of protein synthesis, enhance resistance to limited oxygen availability, and improve protein synthesis capacity under inorganic nitrogen provision.

CONCLUSIONS

All potential users are invited to browse YaliFunTome in the search for homologous TFs and the TF-driven phenotypes of interest.

Transcription factors enhancing synthesis of recombinant proteins and resistance to stress in Yarrowia lipolytica

Resistance to environmental stress and synthesis of recombinant proteins (r-Prots) are both complex, strongly interconnected biological traits relying on orchestrated contribution of multiple genes. This, in turn, makes their engineering a challenging task. One of the possible strategies is to modify the operation of transcription factors (TFs) associated with these complex traits. The aim of this study was to examine the potential implications of selected five TFs (HSF1-YALI0E13948g, GZF1-YALI0D20482g, CRF1-YALI0B08206g, SKN7-YALI0D14520g, and YAP-like-YALI0D07744g) in stress resistance and/or r-Prot synthesis in Yarrowia lipolytica. The selected TFs were over-expressed or deleted (OE/KO) in a host strain synthesizing a reporter r-Prot. The strains were subjected to phenotype screening under different environmental conditions (pH, oxygen availability, temperature, and osmolality), and the obtained data processing was assisted by mathematical modeling. The results demonstrated that growth and the r-Prot yields under specific conditions can be significantly increased or decreased due to the TFs' engineering. Environmental factors "awakening" individual TFs were indicated, and their contribution was mathematically described. For example, OE of Yap-like TF was proven to alleviate growth retardation under high pH, while Gzf1 and Hsf1 were shown to serve as universal enhancers of r-Prot production in Y. lipolytica. On the other hand, KO of SKN7 and HSF1 disabled growth under hyperosmotic stress. This research demonstrates the usefulness of the TFs engineering approach in the manipulation of complex traits and evidences newly identified functions of the studied TFs. KEY POINTS: • Function and implication in complex traits of 5 TFs in Y. lipolytica were studied. • Gzf1 and Hsf1 are the universal r-Prots synthesis enhancers in Y. lipolytica. • Yap-like TF's activity is pH-dependent; Skn7 and Hsf1 act in osmostress response.

Impact of oxygen availability on heterologous geneexpression and polypeptide secretion dynamics in Yarrowia lipolytica-based protein production platforms

Industrially relevant traits of Yarrowia lipolytica, like high growth rate, capacity to grow at high cell density or to synthesize biomolecules with high productivities, strongly rely on sufficient oxygen provision. Although the impact of oxygen availability (OA) on the physiology of Y. lipolytica has been already studied, its influence on recombinant protein (rProt) synthesis and secretion has been largely neglected to date. With the aim to fill this gap, a fluorescent reporter protein (yellow fluorescent protein [YFP]) was used herein as a proxy to follow simultaneously rProt synthesis and secretion in Y. lipolytica under different OAs. This study covers the analysis of the reporter gene expression through reverse transcription quantitative polymerase chain reaction, polypeptide synthesis and its retention-to-secretion ratio using flow cytometry and fluorymetry during shake flasks and bioreactor cultivations under different OA. The results gathered demonstrate that OA has a dramatic impact on the kinetics of intracellular and extracellular YFP accumulation. Higher rProt production and secretion were favoured under high OA, and were largely related to OA and not to cell growth. Our observations also suggest the existence of some upper limit of secretory protein accumulation inside the cells above which massive secretion is initiated. Moreover, at low OA, the first bottleneck in rProt synthesis occurs as early as at transcription level, which could results from a lower availability of transcriptional machinery elements. Finally, using flow cytometry and bioreactor cultivations, we highlighted that ovoid cells are generally more efficient in terms of rProt synthesis.

Optimization of Yarrowia lipolytica-based consolidated biocatalyst through synthetic biology approach: transcription units and signal peptides shuffling

Abstract

Nowadays considerable effort is being pursued towards development of consolidated microbial biocatalysts that will be able to utilize complex, non-pretreated substrates and produce valuable compounds. In such engineered microbes, synthesis of extracellular hydrolases may be fine-tuned by different approaches, like strength of promoter, type of secretory tag, and gene copy number. In this study, we investigated if organization of a multi-element expression cassette impacts the resultant Yarrowia lipolytica transformants’ phenotype, presuming that different variants of the cassette are composed of the same regulatory elements and encode the same mature proteins. To this end, Y. lipolytica cells were transformed with expression cassettes bearing a pair of genes encoding exactly the same mature amylases, but fused to four different signal peptides (SP), and located interchangeably in either first or second position of a synthetic DNA construction. The resultant strains were tested for growth on raw and pretreated complex substrates of different plant origin for comprehensive examination of the strains’ acquired characteristics. Optimized strain was tested in batch bioreactor cultivations for growth and lipids accumulation. Based on the conducted research, we concluded that the positional order of transcription units (TU) and the type of exploited SP affect final characteristics of the resultant consolidated biocatalyst strains, and thus could be considered as additional factors to be evaluated upon consolidated biocatalysts optimization.

Key Points

• Y. lipolytica growing on raw starch was constructed and tested on different substrates.

• Impact of expression cassette design and SP on biocatalysts’ phenotype was evidenced.

• Consolidated biocatalyst process for lipids production from starch was conducted.

Electronic supplementary material

The online version of this article (10.1007/s00253-020-10644-6) contains supplementary material, which is available to authorized users.

Synaptic targeting and localization of discs-large is a stepwise process controlled by different domains of the protein

BACKGROUND

Membrane-associated guanylate kinases (MAGUKs) assemble ion channels, cell-adhesion molecules and components of second messenger cascades into synapses, and are therefore potentially important for co-ordinating synaptic strength and structure. Here, we have examined the targeting of the Drosophila MAGUK Discs-large (DLG) to larval neuromuscular junctions.

RESULTS

During development, DLG was first found associated with the muscle subcortical compartment and plasma membrane, and later was recruited to the postsynaptic membrane. Using a transgenic approach, we studied how mutations in various domains of the DLGprotein affect DLG targeting. Deletion of the HOOK region-the region between the Src homology 3 (SH3) domain and the guanylate-kinase-like (GUK) domain-prevented association of DLG with the subcortical network and rendered the protein largely diffuse. Loss of the first two PDZ domains led to the formation of large clusters throughout the plasma membrane, with scant targeting to the neuromuscular junction. Proper trafficking of DLG missing the GUK domain depended on the presence of endogenous DLG.

CONCLUSIONS

Postsynaptic targeting of DLG requires a HOOK-dependent association with extrasynaptic compartments, and interactions mediated by the first two PDZ domains. The GUK domain routes DLG between compartments, possibly by interacting with recently identified cytoskeletal-binding partners.

The Drosophila beta-amyloid precursor protein homolog promotes synapse differentiation at the neuromuscular junction

Although abnormal processing of beta-amyloid precursor protein (APP) has been implicated in the pathogenic cascade leading to Alzheimer's disease, the normal function of this protein is poorly understood. To gain insight into APP function, we used a molecular-genetic approach to manipulate the structure and levels of the Drosophila APP homolog APPL. Wild-type and mutant forms of APPL were expressed in motoneurons to determine the effect of APPL at the neuromuscular junction (NMJ). We show that APPL was transported to motor axons and that its overexpression caused a dramatic increase in synaptic bouton number and changes in synapse structure. In an Appl null mutant, a decrease in the number of boutons was found. Examination of NMJs in larvae overexpressing APPL revealed that the extra boutons had normal synaptic components and thus were likely to form functional synaptic contacts. Deletion analysis demonstrated that APPL sequences responsible for synaptic alteration reside in the cytoplasmic domain, at the internalization sequence GYENPTY and a putative G(o)-protein binding site. To determine the likely mechanisms underlying APPL-dependent synapse formation, hyperexcitable mutants, which also alter synaptic growth at the NMJ, were examined. These mutants with elevated neuronal activity changed the distribution of APPL at synapses and partially suppressed APPL-dependent synapse formation. We propose a model by which APPL, in conjunction with activity-dependent mechanisms, regulates synaptic structure and number.

The gene mod(mdg4) affects synapse specificity and structure in Drosophila

The mechanisms by which synapse assembly and maturation are orchestrated during development are largely unknown. We used P-element mutagenesis and a larval anatomical screen to isolate mutants in which synapse structure was altered. Here, we describe a mutation isolated with this screen, branch point disrupted (bpd), in which both synapse specificity and synapse morphology were altered. Synaptic terminals in bpd mutants developed abnormally, forming multiple branch points, overgrowing to inappropriate neighboring muscles, and establishing aberrant folding of postsynaptic membranes. Ultrastructural characterization of synaptic boutons in bpd demonstrated abnormal layering of the postsynaptic specialization or subsynaptic reticulum (SSR). Genetic and molecular analyses revealed that bpd is an allele of mod(mdg4), a gene coding for a protein with many similarities to transcription factors, which has been implicated in the regulation of chromatin insulation. Our results suggest that mod(mdg4) may regulate a gene(s) essential to normal synapse formation.

Essential role for dlg in synaptic clustering of Shaker K+ channels in vivo

The assemblage of specific ion channels and receptors at synaptic sites is crucial for signaling between pre- and postsynaptic cells. However, the mechanisms by which proteins are targeted to and clustered at synapses are poorly understood. Here we show that the product of the Drosophila discs-large gene, DLG, is colocalized with Shaker K+ channels, which are clustered at glutamatergic synapses at the larval neuromuscular junction. In heterologous cells, DLG can cluster Shaker-type K+ channels, and, in the yeast two-hybrid system, the DLG PDZ1-2 domains bind directly to the C-terminal tail of Shaker proteins. We also demonstrate that DLG-Shaker interactions are required in vivo for Shaker clustering at the neuromuscular junction. Synaptic clustering of Shaker channels is abolished not only by mutations in dlg but also by a mutation in Shaker that deletes its C-terminal DLG binding motif. Analyses of various dlg mutant alleles suggest that channel clustering and synaptic targeting functions depend on distinct DLG domains. These studies demonstrate for the first time that DLG plays an important role in synaptic organization in vivo that correlates with its ability to bind directly to specific membrane proteins of the synapse.

Regulation of synapse structure and function by the Drosophila tumor suppressor gene dlg

Mutations of the tumor suppressor gene discs-large (dlg) lead to postsynaptic structural defects. Here, we report that mutations in dlg also result in larger synaptic currents at fly neuromuscular junctions. By selectively targeting DLG protein to either muscles or motorneurons using Gal-4 enhancer trap lines, we were able to rescue substantially the reduced postsynaptic structure in mutants. Rescue of the physiological defect was accomplished by presynaptic, but not postsynaptic targeting, consistent with our finding that miniature excitatory junctional currents were not changed in dlg mutants. These results suggest that DLG functions in the regulation of neurotransmitter release and postsynaptic structure. We propose that DLG is an integral part of a mechanism by which changes in both neurotransmitter release and synapse structure are accomplished during development and plasticity.

The Drosophila tumor suppressor gene, dlg, is involved in structural plasticity at a glutamatergic synapse

BACKGROUND

Synaptic contacts between neurons and their targets are dynamic entities that can change depending on developmental and functional states of the pre- and postsynaptic cell. However, the molecular factors involved in this plasticity have remained largely unknown. We have demonstrated previously that the Drosophila tumor suppressor gene, discs-large (dlg), is expressed at neuromuscular synapses, and is required for normal synapse structure. A family of dlg homologues is also expressed at mammalian synapses, where they interact with the N-methyl-D-aspartate receptor and ion channels. Here, we provide the first demonstration of the involvement of dlg in structural synaptic plasticity during postsynaptic target growth.

RESULTS

We used a temperature-sensitive dlg allele to demonstrate that there are two stages, late embryogenesis and larval stages, at which dlg is necessary for normal formation of synapses. These stages are coincident with dynamic DLG expression at presynaptic sites in the late embryo, and at postsynaptic regions in the larva. Ultrastructural and confocal analyses reveal that Drosophila neuromuscular junctions undergo a dramatic expansion of the postsynaptic apparatus, which is paralleled by target muscle growth. We show that this process of postsynaptic expansion is partially blocked in dlg mutants.

CONCLUSIONS

Our results demonstrate that dlg is required during synapse maturation. We show that dlg is involved in the determination of postsynaptic size during target muscle growth. Because motoneuron targets in the larva are continuously growing, synaptic contacts are structurally plastic, undergoing continuous expansion. We conclude that dlg plays an important role in this form of structural synaptic plasticity.

Chemical and pharmacological properties of new tetrahydropyrimido-[2,1-f]-purines

Following a research program on piperazinoalkyl-substituted tricyclic purines, a number of N-9-aryl(alkyl)-piperazinopropyl substituted tetrahydropyrimido-[2,1-f]-purines were synthesized and tested pharmacologically with respect to their influence on the central nervous system. Two of the new compounds induced hypothermia and decreased the spontaneous locomotor activity of mice.

Octopamine immunoreactivity in the fruit fly Drosophila melanogaster

Octopamine has been proposed as a neurotransmitter/modulator/hormone serving a variety of physiological functions in invertebrates. We have initiated a study of octopamine in the fruit fly Drosophila melanogaster, which provides an excellent system for genetic and molecular analysis of neuroactive molecules. As a first step, the distribution of octopamine immunoreactivity was studied by means of an octopamine-specific antiserum. We focused on the central nervous system (CNS) and on the innervation of the larval body wall muscles. The larval octopamine neuronal pattern was composed of prominent neurons along the midline of the ventral ganglion, whereas brain lobes were devoid of immunoreactive somata. However, intense immunoreactive neuropil was observed both in the ventral ganglion and in the brain lobes. Some of the immunoreactive neurons sent peripheral fibers that innervated most of the muscles of the larval body wall. Octopamine immunoreactivity was observed at neuromuscular junctions in all larval stages, being present in a well-defined subset of synaptic boutons, type II. Octopamine immunoreactivity in the adult CNS revealed many additional neurons compared to the larval CNS, indicating that at least a subset of adult octopamine neurons may differentiate during metamorphosis. Major octopamine-immunoreactive neuronal clusters and neuronal processes were observed in the subesophageal ganglion, deutocerebrum, and dorsal protocerebrum, and intense neuropil staining was detected primarily in the optic lobes and in the central complex.

Tricyclic theophylline derivatives with high water-solubility: structure-activity relationships at adenosine receptors, phosphodiesterases, and benzodiazepine binding sites

A series of tricyclic, highly water-soluble theophylline derivatives (pyrimido[2,1-f]-theophyllines) containing a basic side chain was investigated in rat brain A1- and A2 adenosine receptor binding assays, phosphodiesterase assays, and benzodiazepine binding studies. Among the new compounds adenosine receptor antagonists with affinities in the same range as the parent compound theophylline were identified. In addition, some compounds were selective for the A1 adenosine receptor subtype. The compounds generally exhibited lower inhibitory activity at brain phosphodiesterases than the parent theophylline. Two compounds were found to show an about 10-fold affinity for benzodiazepine binding sites compared with caffeine and theophylline.

The influence of new 9-(omega-[4-(2-pyrimidinyl)-1-piperazinyl]alkyl) pyrimidino[2,1-f]purines on the central nervous system

Synthesis and the results of preliminary pharmacological evaluation of four new 9-substituted pyrimidino[2,1-f]purines, containing pyrimidinyl-piperazine substituent are described. Some of these substances induced hypothermia, antagonism of amphetamine action and neurotoxic effects. All compounds had weaker activity on the central nervous system than previously studied compounds containing phenyl-piperazine substituent.

The Drosophila tumor suppressor gene dlg is required for normal synaptic bouton structure

The Drosophila tumor suppressor gene lethal (1) discs large (dlg) encodes a protein necessary for normal cell growth in epithelial and brain tissue. It shares high sequence identity to the mammalian synaptic proteins PSD-95 and SAP-70, whose functions are unknown. To determine the localization and role of dlg at synapses, we investigated its distribution and the effects of dlg mutations on Drosophila neuromuscular junctions. We show that dlg immunoreactivity is expressed at one type of glutamatergic synapse and is associated with both presynaptic and postsynaptic membranes. Mutations in dlg alter the expression of dlg and cause striking changes in the structure of the subsynaptic reticulum, a postsynaptic specialization at these synapses. These results indicate that dlg is required for normal synaptic structure and offer insights regarding the role of dlg homologs at vertebrate synapses.

Insulin-like receptor and insulin-like peptide are localized at neuromuscular junctions in Drosophila

Insulin and insulin-like growth factor (IGF) receptors are members of the tyrosine kinase family of receptors, and are thought to play an important role in the development and differentiation of neurons. Here we report the presence of an insulin-like peptide and an insulin receptor (dInsR) at the body wall neuromuscular junction of developing Drosophila larvae. dInsR-like immunoreactivity was found in all body wall muscles at the motor nerve branching regions, where it surrounded synaptic boutons. The identity of this immunoreactivity as a dInsR was confirmed by two additional schemes, in vivo binding of labeled insulin and immunolocalization of phosphotyrosine. Both methods produced staining patterns markedly similar to dInsR-like immunoreactivity. The presence of a dInsR in whole larvae was also shown by receptor binding assays. This receptor was more specific for insulin (> 25-fold) than for IGF II, and did not appear to bind IGF I. Among the 30 muscle fibers per hemisegment, insulin-like immunoreactivity was found only on one fiber, and was localized to a subset of morphologically distinct synaptic boutons. Staining in the CNS was limited to several cell bodies in the brain lobes and in a segmental pattern throughout most of the abdominal ganglia, as well as in varicosities along the neuropil areas of the ventral ganglion and brain lobes. Insulin-like peptide and dInsR were first detected by early larval development, well after neuromuscular transmission begins. The developmental significance of an insulin-like peptide and its receptor at the neuromuscular junction is discussed.

Ultrastructure of neuromuscular junctions in Drosophila: comparison of wild type and mutants with increased excitability

The ventral longitudinal muscles of the Drosophila larval body wall are innervated by at least four types of synaptic terminals that can be distinguished on morphological grounds at the light microscopical level. The innervation of these muscles has been previously shown to be regulated by neuronal activity. In this report we investigate the ultrastructural basis for synaptic bouton differences by using serial sections, and examine the structure of synaptic terminals in mutants with increased excitability. We report that individual identifiable muscle fibers are innervated by terminals containing two to three types of synaptic boutons that can be distinguished in terms of synaptic vesicle population, presynaptic and postsynaptic specialization, and general shape. We propose a model to account for the bouton types observed at the light microscopical level. We find that in the hyperexcitable mutant eag Sh, there are dramatic ultrastructural alterations at synaptic boutons. These alterations include a partial depletion of two types of synaptic vesicles and a change in appearance of a third type, changes in number and appearance of synaptic densities, and the presence of multivesicular bodies. Our results show that an increase in neuronal excitability produces profound effects in synaptic terminal structure.

Synthesis, physicochemical and preliminary pharmacological properties of N-[beta-hydroxy-gamma-(N-phenylpiperazinepropyl)]-2-pyrrolidinone

The present paper reports on the synthesis and preliminary pharmacological properties of N-[beta-hydroxy-gamma-(N-phenylpiperazinepropyl)]-2- pyrrolidinone (MG-1). MG-1 was obtained by aminolysis of 1-(beta, gamma-epoxypropyl)-2-pyrrolidinone and N-phenylpiperazine. Its structure was established by elemental and spectral analyses (IR, UV, MS, 1H, 13C, 2D H-H and 2D C-H NMR). The antiarrhythmic activity of MG-1 was investigated on mice, rats and guinea pigs, using several models of arrhythmia. MG-1 attenuated or prevented the adrenaline- and barium chloride-induced arrhythmia. MG-1 demonstrated potent local anesthetic properties and depressed the depolarization phase of the action potential of cardiac cells. These results indicate that MG-1 possesses antiarrhythmic activity.

SSB, an antigen that selectively labels morphologically distinct synaptic boutons at the Drosophila larval neuromuscular junction

In this report we describe the expression of Small Synaptic Bouton (SSB), an antigen that is selectively expressed in a specific subset of neuromuscular junction terminals in the body wall of Drosophila larva. The expression of SSB was studied with a polyclonal antibody raised against the cAMP phosphodiesterase of the Drosophila learning mutant dunce (Nighorn et al., 1991, Neuron 6:455-467); however, immunoreactivity was not abolished by the dunce (dnc) alleles dncM14 and dncM11 or deficiencies of the dnc gene, indicating that the antigen labelled could not be the dnc gene product, but another antigen that we termed SSB. Immunoreactivity was localized in the body wall muscles to a specific subset of neuromuscular junction terminals that have been implicated in activity-dependent plasticity. This demonstrates that these morphologically distinct terminals can be immunocytochemically distinguished and that they probably represent innervation by a distinct neuronal population. Confocal and electron microscopic examination demonstrated that staining was restricted to the synaptic boutons themselves, not to neurites or motor axons. Ultrastructural analysis showed label close to synaptic vesicles in the presynaptic terminal and in the surrounding subsynaptic reticulum. Central nervous system (CNS) staining was restricted to a segmentally repeated pattern of cell bodies in the ventral ganglion and to a few small groups of cells in the brain lobes.

Synthesis and preliminary pharmacological assessment of novel 9-alkylamino substituted pyrimidino-[2,1-f]-purines

Two series of N9-alkylaminomethyl-, alkylpiperazino-, alkylpiperidino-substituted 1,3-dimethyl-(hexahydropyrimidino)- and (tetrahydropyrimidono)-[2,1-f]-purines were prepared and their physicochemical and pharmacological properties were described. The most active in central nervous system tests were the compounds with phenylpiperazinealkyl substituent i.e. 1,3-dimethyl-2,4-dioxo-9-[N1N4-(phenyl)-piperazinopropyl]-1, 3,6,7,8,9- hexahydropyrimidino-[2,1-f] purine 6a and its butyl and isobutyl homologs 9 and 12. The compounds depressed statistically significantly spontaneous locomotor and amphetamine activity and showed sedative, analgetic and hypothermizing properties.

Synthesis and preliminary pharmacological assessment of novel 9-substituted pyrimidino-[2,1-f]-purines

Synthesis, chemical properties and results of preliminary pharmacological evaluation of several new 9-substituted pyrimidino-[2,1-f]-purines are described. The most interesting was 1,3-dimethyl-2,4,8-trioxo-9-[gamma-N1-(N4-C6H5)-piperazynopropy l]-1,3,6,7-tetrahydro-9H-pyrimidino-[2,1-f]-purine (compound 4a), which exerted strong sedative, hypothermizing and cataleptogenic action and possessed some anti-amphetamine and anti-apomorphine properties.

Synthesis and preliminary pharmacological assessment of novel gamma-hydroxybutyric acid derivatives

Synthesis and properties of new N-substituted amides of alpha-(1,1-ethylenedioxy)-ethyl-gamma-hydroxybutyric acid are described. The compounds were obtained by aminolysis of 3-(1,1-ethylenedioxy)-ethyltetra-hydrofuran-2-on with primary alkylarylamines. Preliminary pharmacological assessment revealed that the compounds exert weaker influence on the central nervous system than the reference gamma-hydroxybutyric acid. Three of the novel compounds offered some protection against pentetrazole-induced tonic seizures in mice.

Synthesis and preliminary pharmacological screening of some 8-substituted methylxanthines

Methods of synthesis, chemical properties and results of preliminary pharmacological screening for 8-amino substituted derivatives of caffeine (1-3) and 7,8-disubstituted derivatives of 8-aminotheophylline (8-12) have been described. The compounds show weak sedative and antidepressive activity and some of them (2, 10, 12) also small antinociceptive effect.

Chemical and pharmacological properties of some 7-beta-hydroxy-gamma-piperazinopropyl-8-benzylaminotheophylli nes

In order to examine the circulatory and bronchospasmolytic activity, new 7-beta-hydroxy-gamma-N4-alkylpiperazinopropyl-8- benzylaminotheophyllines (1, 2, 3) were synthesized and converted to the water soluble dihydrochlorides (1a, 2a, 3a). They showed hypotensive and bronchodilatory effect.

Identification of a cholinergic synapse in the giant fiber pathway of Drosophila using conditional mutations of acetylcholine synthesis

Temperature-sensitive mutations of the choline acetyltransferase (Cha) gene, which lead to reduced choline acetyltransferase (ChAT) activity and acetylcholine (ACh) levels, have been used in an attempt to identify the neurotransmitter at a chemical synapse in the giant fiber pathway (GFP) of Drosophila melanogaster. Prolonged incubation of adult mutant flies at non-permissive temperatures blocked the response of this pathway to brain stimulation, whereas shorter incubation times disturbed various parameters of the normal response. Even at permissive temperature subnormal responses were still evident. These defects in the giant fiber pathway's function suggest a specific cholinergic synapse within the pathway, the first synapse of this type implicated in Drosophila. When the function of this synapse was experimentally stressed, disruptions of GFP function paralleling decreased ChAT activity began to appear at enzyme levels estimated to be approximately 80% of wild-type.

Synthesis and pharmacological properties of some 2-pyrrolidinone Mannich bases

N-aminoalkyl derivatives of 2-pyrrolidinone (1-5) and methylene-bis-amino derivatives (7-9) as intermediary products formed during aminoalkylation were described. Compounds 2 and 3, in doses over 30 and 20 mg/kg resp., displayed analgesic properties; compound 3 exerted also a weak anti-inflammatory action (37 mg/kg po) in the carrageenin test.

Synthesis and properties of 7-hydroxyalkyl- and 7-hydroxyalkylamino-8-benzylaminotheophylline derivatives

In a search for new compounds with cardiovascular activity several derivatives of 8-benzylaminotheophylline with hydroxyalkyl and hydroxyalkylamino substituents at 7-position have been obtained. Some of these compounds were screened for their hypotensive activity.

Synthesis and pharmacological properties of 1,3 and 5-substituted 2-pyrrolidinones

We described synthesis of 1-aryl-3 and 5-substituted 2-pyrrolidinones (2a--5a and 3b--4b). Pharmacological studies revealed that compounds 3b, 4a and 4b have analgetic and antiinflammatory properties. None of the compounds posesses neuroleptic or anticonvulsant properties.

Synthesis and properties of 7-hydroxyalkyl-8-benzylaminotheophyllines

The synthetic routes leading to 7-beta-hydroxyethyl- (I) and 7-beta-hydroxypropyl-8-benzylaminotheophylline (II) were described. Particularly the opening of oxazolidine ring in easy available oxazolidine-(2,3-f)-theophyllines with benzylamine was investigated. The structure of I, II and acetyl derivatives Ia, Ib, IIa and IIb was also confirmed by UV spectra.