Heat-Introduced Formation of Acrylamide in Table Olives: Analysis of Acrylamide, Free Asparagine, and 3-Aminopropionamide

Acrylamide was detected in considerable amounts in black table olives. In this study, besides black, also green and naturally black table olives were investigated for their acrylamide, free asparagine, and 3-aminopropionamide contents before and after heat treatment. Acrylamide amount was 208-773 μg/kg in black table olives and did not change due to heat treatment. In green and naturally black table olives acrylamide was ≤24 μg/kg before heat treatment and rose to 1200 μg/kg afterward. Asparagine content was 0.35-35 mg/kg in all samples before heat treatment and after heat treatment with no considerable change in the range. 3-Aminopropionamide showed amounts of ≤56 μg/kg in the unheated samples and increased up to 131 μg/kg due to heat impact. However, quantified asparagine and 3-aminopropionamide amounts were insufficient in almost all samples to explain the acrylamide quantities formed due to heat treatment based on the formation via the Maillard reaction.

Determination of E 472b emulsifiers in foamed food formulations by high-performance thin-layer chromatography‒fluorescence detection

E 472b emulsifiers, defined as lactic acid esters of mono- and diacylglycerides, are food emulsifiers widely used in foamed food formulations. So far, only qualitative methods for analyzing E 472b emulsifiers have been published. Thus, a new method was developed for determining E 472b in different foamed food formulations by high-performance thin-layer chromatography with fluorescence detection (HPTLC‒FLD). The proposed method allows simple and fast E 472b emulsifier extraction from the food matrix and points out an analytical approach for quantifying these emulsifiers using a commercial E 472b emulsifier as the reference standard. Limits of decision with 56‒59 ng of E 472b emulsifier/zone and limits of quantification with 172‒179 ng of E 472b emulsifier/zone in three foamed model food formulations, respectively, as well as satisfactory repeatability (n = 6) and reproducibility (n = 6) exposed by low relative standard deviation < 8% proved the method suitable for the sensitive and reliable determination of E 472b emulsifiers. Recoveries between 96 and 109.3% were obtained for all investigated model systems. In commercial foamed food formulations from the German market, the E 472b emulsifier content ranged between 0.1 and 0.6 g/100 g.

Exploration of surfactin production by newly isolated Bacillus and Lysinibacillus strains from food related sources

As a lipopeptide (LP), surfactin exhibits properties, such as emulsifying and dispersing ability, which are useful in food industry. Discovery of new LP-producing strains from food sources is an important step towards possible application of surfactin in foods. A total of 211 spore-forming, Gram-positive, and catalase-positive bacterial strains were isolated from fermented African locust beans (iru) and Palm Oil Mill Effluents in a screening process and examined for their ability to produce surfactin. This was achieved by a combination of methods, which included microbiological and molecular classification of strains, along with chemical analysis of surfactin production. Altogether, 29 isolates, positive for oil spreading and emulsification assays, were further identified with 16S rDNA analysis. The strains belonged to nine species including less commonly reported strains of Lysinibacillus, Bacillus flexus, B. tequilensis, and B. aryabhattai. The surfactin production was quantitatively and qualitatively analyzed by high-performance thin-layer chromatography (HPTLC) and liquid chromatography-mass spectrometry (LC-MS). Confirmation of surfactin by MS was achieved in all the 29 strains. Highest surfactin production capability was found in B. subtilis IRB2-A1 with a titer of 1444.1 mg L^-1 .

Screening for mineral oil hydrocarbons in vegetable oils by silver ion-planar solid phase extraction

The analysis of mineral oil hydrocarbons in vegetable oils is challenging especially regarding the analysis of mineral oil aromatic hydrocarbons (MOAH) since native terpenes like squalene or β-carotene are usually extracted along with the MOAH fraction and interfere their detection. When applying a recently developed screening method for the analysis of mineral oil saturated hydrocarbons (MOSH) and MOAH in paper and cardboard by planar solid phase extraction (pSPE) to vegetable oils, native terpenes expectably interfered with MOAH analysis. Thus, an adaption of pSPE employing silver ions, named silver ion-planar solid phase extraction (Ag-pSPE), was developed in this study. Impregnation of thin-layers with silver nitrate (AgNO₃) was found to be very successful in retaining squalene and β-carotene. MOAH analysis of vegetable oils after saponification showed good repeatability (relative standard deviation (%RSD) <10%) and recoveries of 73.4-112.4% at a spiking level of 4.5 mg/kg (n = 4). For MOSH analysis, a simple solid phase extraction (SPE) clean-up with aluminum oxide removed native n-alkanes prior to Ag-pSPE. Recoveries for MOSH were 55.3-84.5% with %RSD <11% at a spiking level of 45.5 mg/kg (n = 4). Limits of decision and quantitation were at 7.2 and 22.2 ng/zone for MOSH and 1.1 and 3.4 ng/zone for MOAH, respectively, which corresponded to the recently introduced pSPE method, thus showing that analytes were not affected by the impregnation of HPTLC plates with AgNO₃. The method comparison with LC-GC showed similar results for MOSH, while the amounts for MOAH determined by Ag-pSPE were higher.

Determination of mono- and diacylglycerols from E 471 food emulsifiers in aerosol whipping cream by high-performance thin-layer chromatography-fluorescence detection

Mono- and diacylglycerol (MAG and DAG) emulsifiers (E 471) are widely applied to regulate techno-functional properties in different food categories, for example, in dairy products. A method for the determination of MAG and DAG in aerosol whipping cream by high-performance thin-layer chromatography with fluorescence detection (HPTLC-FLD) after derivatization with primuline was developed. For sample preparation, aerosol whipping cream was mixed with ethanol, followed by the addition of water and liquid-liquid extraction with tert-butyl methyl ether. The sample extracts were analyzed by HPTLC-FLD on silica gel LiChrospher plates with n-pentane/n-hexane/diethyl ether (22.5:22.5:55, v/v/v) as mobile phase, when interfering matrix like cholesterol and triacylglycerols were successfully separated from the E 471 food additives. For quantitation, an emulsifier with known composition was used as calibration standard and the fluorescent MAG and DAG were scanned at 366/> 400 nm. Limits of detection and quantitation of 4 and 11 mg/100 g aerosol whipping cream were obtained for both monostearin and 1,2-distearin, respectively, and allowed the reliable quantitation of MAG and DAG from E 471 far below commonly applied emulsifier amounts. Recoveries from model aerosol whipping cream with 400 mg E 471/100 g were determined in a calibration range of 200-600 mg E 471/100 g sample and ranged between 86 and 105% with relative standard deviations below 7%. In aerosol whipping creams from the German market, E 471 amounts ranged between 384 and 610 mg/100 g.

Rapid Planar Chromatographic Analysis of 25 Water-Soluble Dyes Used as Food Additives

A rapid planar chromatographic method for identification and quantification of 25 water-soluble dyes in food was developed. In a horizontal developing chamber, the chromatographic separation on silica gel 60F254 high-performance thin-layer chromatography plates took 12 min for 40 runs in parallel, using 8 mL ethyl acetatemethanolwateracetic acid (65 + 23 + 11 + 1, v/v/v/v) mobile phase up to a migration distance of 50 mm. However, the total analysis time, inclusive of application and evaluation, took 60 min for 40 runs. Thus, the overall time/run can be calculated as 1.5 min with a solvent consumption of 200 L. A sample throughput of 1000 runs/8 h day can be reached by switching between the working stations (application, development, and evaluation) in a 20 min interval, which triples the analysis throughput. Densitometry was performed by absorption measurement using the multiwavelength scan mode in the UV and visible ranges. Repeatabilities [relative standard deviation (RSD), 4 determinations] at the first or second calibration level showed precisions of mostly 2.7, ranging between 0.2 and 5.2. Correlation coefficient values (R 0.9987) and RSD values (4.2) of the calibration curves were highly satisfactory using classical quantification. However, digital evaluation of the plate image was also used for quantification, which resulted in RSD values of the calibration curves of mostly 3.0, except for two 6.0. The method was applied for the analysis of some energy drinks and bakery ink formulations, directly applied after dilution. By recording of absorbance spectra in the visible range, the identities of the dyes found in the samples were ascertained by comparison with the respective standard bands (correlation coefficients 0.9996). If necessary for confirmation, online mass spectra were recorded within a minute.

Characterization of E 471 food emulsifiers by high-performance thin-layer chromatography-fluorescence detection

Mono- and diacylglycerol (MAG and DAG) emulsifiers, also known as food additive E 471, are widely used to adjust techno-functional properties in various foods. Besides MAGs and DAGs, E 471 emulsifiers additionally comprise different amounts of triacylglycerols (TAGs) and free fatty acids (FFAs). MAGs, DAGs, TAGs and FFAs are generally determined by high-performance liquid chromatography (HPLC) or gas chromatography (GC) coupled to mass selective detection, analyzing the individual representatives of the lipid classes. In this work we present a rapid and sensitive method for the determination of MAGs, DAGs, TAGs and FFAs in E 471 emulsifiers by high-performance thin-layer chromatography with fluorescence detection (HPTLC-FLD), including a response factor system for quantitation. Samples were simply dissolved and diluted with t-butyl methyl ether before a two-fold development was performed on primuline pre-impregnated LiChrospher silica gel plates with diethyl ether and n-pentane/n-hexane/diethyl ether (52:20:28, v/v/v) as the mobile phases to 18 and 75 mm, respectively. For quantitation, the plate was scanned in the fluorescence mode at UV 366/>400 nm, when the cumulative signal for each lipid class was used. Calibration was done with 1,2-distearin and amounts of lipid classes were calculated with response factors and expressed as monostearin, distearin, tristearin and stearic acid. Limits of detection and quantitation were 1 and 4 ng/zone, respectively, for 1,2-distearin. Thus, the HPTLC-FLD approach represents a simple, rapid and convenient screening alternative to HPLC and GC analysis of the individual compounds. Visual detection additionally enables an easy characterization and the direct comparison of emulsifiers through the lipid class pattern, when utilized as a fingerprint.

Determination of caffeine, theobromine and theophylline in Mate beer and Mate soft drinks by high-performance thin-layer chromatography

Mate beer and Mate soft drinks are beverages produced from the dried leaves of Ilex paraguariensis (Yerba Mate). In Yerba Mate, the xanthine derivatives caffeine, theobromine and theophylline, also known as methylxanthines, are important active components. The presented method for the determination of caffeine, theobromine and theophylline in Mate beer and Mate soft drinks by high-performance thin-layer chromatography with ultraviolet detection (HPTLC-UV) offers a fully automated and sensitive determination of the three methylxanthines. Filtration of the samples was followed by degassing, dilution with acetonitrile in the case of Mate beers for protein precipitation, and centrifugation before the extracts were analyzed by HPTLC-UV on LiChrospher silica gel plates with fluorescence indicator and acetone/toluene/chloroform (4:3:3, v/v/v) as the mobile phase. For quantitation, the absorbance was scanned at 274nm. Limits of detection and quantitation were 1 and 4ng/zone, respectively, for caffeine, theobromine and theophylline. With recoveries close to 100% and low standard deviations reliable results were guaranteed. Experimental Mate beers as well as Mate beers and Mate soft drinks from the market were analyzed for their concentrations of methylxanthines.

High-performance thin-layer chromatography (HPTLC) for the simultaneous quantification of the cyclic lipopeptides Surfactin, Iturin A and Fengycin in culture samples of Bacillus species

A high-performance thin-layer chromatography method has been established for the identification and simultaneous quantification of the cyclic lipopeptides Surfactin, Iturin A and Fengycin in Bacillus culture samples. B. subtilis DSM 10^T, B. amyloliquefaciens DSM 7^T and B. methylotrophicus DSM 23117 were used as model strains. Culture samples indicated that a sample pretreatment is necessary in order to run HPTLC analyses. A threefold extraction of the cell-free broth with the solvent chloroform/methanol (2:1, v/v) gave best results, when all three lipopeptides were included in the analysis. For the mobile phase, a two-step development was considered most suitable. The first development is conducted with chloroform/methanol/water (65:25:4, v/v/v) over a migration distance of 60mm and the second development using butanol/ethanol/0.1% acetic acid (1:4:1, v/v/v) over a migration distance of 60mm, as well. The method was validated according to Validation of Analytical Procedures: Methodology (FDA Guidance) with respect to the parameters linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy and recovery rate. A linear range with R²>0.99 was obtained for all samples from 30ng/zone up to 600ng/zone. The results indicated that quantification of Surfactin has to be performed after the first development (hR_F=44), while Fengycin is quantified after the second development (hR_F=36, hR_F range=20-40). For Iturin A, the results demonstrated that quantification is in favor after the first (hR_F=19) development, but also possible after the second (hR_F=59) development. LOD and LOQ for Surfactin and Iturin A after the first development, and Fengycin after the second development were determined to be 16ng/zone and 47ng/zone, 13ng/zone and 39ng/zone, and 27ng/zone and 82ng/zone, respectively. Results further revealed the highly accurate and precise character of the developed method with a good inter- and intraday reproducibility. For the precision and accuracy, expressed as % recovery and relative standard deviation, respectively, the determined values did not exceed ±15% as specified by the FDA Guidance. The recovery assay conducted for samples obtained from two strains with the solvent chloroform/methanol (2:1, v/v), which was determined to be most suitable if all three lipopeptides are of interest, gave recoveries of 96.5% and 99.6%, 68.6% and 71.6%, and 102.5% and 95.2% for Surfactin, Iturin A and Fengycin, respectively. Overall, a suitable and reliable method for the simultaneous quantification of the lipopeptides Surfactin, Iturin A and Fengycin in biological samples using HPTLC was successfully developed and validated.

Screening for Ricinoleic Acid as a Chemical Marker for Secale cornutum in Rye by High-Performance Thin-Layer Chromatography with Fluorescence Detection

Ricinoleic acid as the characteristic fatty acid of Secale cornutum oil is a good marker for Secale cornutum impurities in cereal. The presented screening for ricinoleic acid in rye by high-performance thin-layer chromatography with fluorescence detection (HPTLC-FLD) offers a selective and sensitive method for the determination of Secale cornutum and is very different from existing gas chromatographic analyses. Lipid extraction was followed by transesterification and solid-phase extraction cleanup; thereafter, extracts were selectively derivatized with 2-naphthoyl chloride and analyzed by HPTLC-FLD with silica gel plates and cyclohexane/diisopropyl ether/formic acid (86:14:1, v/v/v) as mobile phase. For quantitation, the enhanced fluorescence was scanned at 280/>340 nm. Limits of detection and quantitation of 0.1 and 0.4 mg ricinoleic acid/kg of rye were obtained, which enables the determination of Secale cornutum far below the maximum admitted level. With near-100% recoveries and low standard deviations at relevant spiking levels, reliable results were guaranteed.

Rapid planar chromatographic analysis of 25 water-soluble dyes used as food additives

A rapid planar chromatographic method for identification and quantification of 25 water-soluble dyes in food was developed. In a horizontal developing chamber, the chromatographic separation on silica gel 60F254 high-performance thin-layer chromatography plates took 12 min for 40 runs in parallel, using 8 mL ethyl acetate-methanol-water-acetic acid (65 + 23 + 11 + 1, v/v/v/v) mobile phase up to a migration distance of 50 mm. However, the total analysis time, inclusive of application and evaluation, took 60 min for 40 runs. Thus, the overall time/run can be calculated as 1.5 min with a solvent consumption of 200 microL. A sample throughput of 1000 runs/8 h day can be reached by switching between the working stations (application, development, and evaluation) in a 20 min interval, which triples the analysis throughput. Densitometry was performed by absorption measurement using the multiwavelength scan mode in the UV and visible ranges. Repeatabilities [relative standard deviation (RSD), 4 determinations] at the first or second calibration level showed precisions of mostly < or = 2.7%, ranging between 0.2 and 5.2%. Correlation coefficient values (R > or = 0.9987) and RSD values (< or = 4.2%) of the calibration curves were highly satisfactory using classical quantification. However, digital evaluation of the plate image was also used for quantification, which resulted in RSD values of the calibration curves of mostly < or = 3.0%, except for two < or = 6.0%. The method was applied for the analysis of some energy drinks and bakery ink formulations, directly applied after dilution. By recording of absorbance spectra in the visible range, the identities of the dyes found in the samples were ascertained by comparison with the respective standard bands (correlation coefficients > or = 0.9996). If necessary for confirmation, online mass spectra were recorded within a minute.

The site of action of neuronal acidic fibroblast growth factor is the organ of Corti of the rat cochlea

Here we show that the mature cochlear neurons are a rich source of acidic fibroblast growth factor (aFGF), which is expressed in the neuronal circuitry consisting of afferent and efferent innervation. The site of action of neuronal aFGF is likely to reside in the organ of Corti, where one of the four known FGF receptor (FGFR) tyrosine kinases--namely, FGFR-3 mRNA--is expressed. Following acoustic overstimulation, known to cause damage to the organ of Corti, a rapid up-regulation of FGFR-3 is evident in this sensory epithelium, at both mRNA and protein levels. The present results provide in vivo evidence for aFGF being a sensory neuron-derived, anterogradely transported factor that may exert trophic effects on a peripheral target tissue. In this sensory system, aFGF, rather than being a neurotrophic factor, seems to promote maintenance of the integrity of the organ of Corti. In addition, aFGF, released from the traumatized nerve endings, may be one of the first signals initiating protective recovery and repair processes following damaging auditory stimuli.

Acidic FGF and FGF receptors are specifically expressed in neurons of developing and adult rat dorsal root ganglia

Employing complementary technical approaches, we have studied the expression of acidic fibroblast growth factor (aFGF) and FGF receptors in rat dorsal root ganglia. The results clearly showed that within spinal nerves aFGF and two high-affinity FGF receptors, FGFR-1 and FGFR-2, were prominently expressed in neurons, while expression in Schwann cells was undetectable. FGFR-3 and FGFR-4 were not expressed in dorsal root ganglia. Acidic FGF mRNA was detected in the majority of dorsal root ganglion neurons, including all size classes: FGFR-1 and FGFR-2 transcripts were only detected in subpopulations of mainly large and medium size neurons. In subcellular fractionation studies on dorsal root ganglion and spinal root tissue, aFGF was recovered in the soluble fraction and was thus not tightly associated with neuronal membranes. During development FGFR-1 and FGFR-2 mRNAs were found to be present at all stages examined (embryonic days 15-21 and postnatal days 1-120). Acidic FGF mRNA and protein were first detected at embryonic day 18, and their expression then increased progressively up to postnatal levels. In cultures of dorsal root ganglion neurons derived from day 15 embryos, aFGF expression was first detected 3 days after plating. The resulting neuron cultures continued to express aFGF in a Schwann cell-independent manner. In combination, these results indicate that aFGF expression in dorsal root ganglia is initiated and maintained in postmitotic neurons. Furthermore, the data suggest that the physiological function of aFGF in the peripheral nervous system is connected to processes specific to the mature sensory (and motor) system, such as the maintenance and survival of peripheral nerve neurons.

Differential expression of acidic and basic FGF in the rat substantia nigra during development

Both acidic (aFGF) and basic (bFGF) fibroblast growth factors have been shown to be present in the adult rat ventral mesencephalon and to exert effects on cultured mesencephalic cells. In the present study we have examined the expression of aFGF and bFGF in the rat ventral mesencephalon at various stages of development. bFGF was present at all ages examined [embryonic day 16 (E16) to postnatal day 90 (P90)]. In contrast, aFGF was not detectable at embryonic and early postnatal ages, but was observed at later (P20, P60, P90) postnatal stages. These data suggest that aFGF and bFGF may have functions in mesencephalic dopamine neurones in different stages of development.

Expression of acidic and basic fibroblast growth factors in the substantia nigra of rat, monkey, and human

The distribution of acidic (aFGF) and basic (bFGF) fibroblast growth factor mRNA and protein were examined in mesencephalon by immunohistochemistry, immunoblot analysis, in situ hybridization histochemistry, and RNA analysis. Coexistence of aFGF or bFGF with tyrosine hydroxylase protein in nigral cells was observed with immunohistochemistry. Both aFGF and bFGF mRNAs were found in the substantia nigra. Unilateral 6-hydroxydopamine lesions of nigrostriatal neurons resulted in a loss of aFGF and tyrosine hydroxylase [L-tyrosine, tetrahydropteridine: oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2] mRNA-positive neurons on the lesioned side. The distribution of aFGF mRNA in monkey brain was similar to that seen in the rat. RNA and immunoblot analysis confirmed the presence of both aFGF and bFGF mRNAs and proteins in the substantia nigra of rat, monkey, and human.

Basic FGF is present in dopaminergic neurons of the ventral midbrain of the rat

Immunocytochemistry procedures and 6-hydroxy-dopamine-induced degeneration of dopamine nerve cells provided evidence that practically all tyrosine hydroxylase immunoreactive (IR) neurons of the substantia nigra and ventral tegmental area contain cytoplasmic basic fibroblast growth factor immunoreactivity (bFGF IR), while many astroglial cells in the neostriatum and substantia nigra contain nuclear bFGF IR. RNA blot analysis demonstrated strong expression of a major 3.7 kb bFGF mRNA in the substantia nigra and ventral tegmental area. These results indicate that bFGF may be a significant growth factor in the DA neurons.

Gene transfer into brain tumor cell lines: reporter gene expression using various cellular and viral promoters

In the present study we determined the optimal conditions for transferring DNA into rat and human brain tumor cell lines of glial and neuronal origin using electroporation as the transfection method. Gene transfer efficiency was measured in terms of transient chloramphenicol acetyltransferase (CAT) activity and stable neomycin expression. Moreover, the activity of a variety of cellular and viral promoters in brain tumor cell lines of distinct origin was characterized. The results revealed various expression patterns, including glial as well as neuronal specific promoter activity.

The expression of the Autographa californica nuclear polyhedrosis virus genome in insect cells

This report presents a synopsis of recently published work in our laboratory on the molecular biology of the insect baculovirus Autographa californica nuclear polyhedrosis virus (AcNPV). The following studies have been summarized. (1) On the mode of transcription of the AcNPV genome in insect cells. (2) Translation of proteins encoded in the 81.2 to 85.0 map unit segment of AcNPV. (3) Inserts of insect cell DNA in the AcNPV genome. (4) Expression of influenza (fowl plague) virus haemagglutinin in Spodoptera frugiperda insect cells, and successful immunization of chickens. (5) Synthesis of the influenza virus haemagglutinin in insect larvae by recombinant AcNPV. This insect virus system will continue to serve as a model for research on the molecular biology of insects. Moreover, the baculovirus system has been recognized as a very efficient and safe eukaryotic expression vector.

An insertion of insect cell DNA in the 81-map-unit segment of Autographa californica nuclear polyhedrosis virus DNA

In this report, a transposonlike insertion of Spodoptera frugiperda insect cell DNA was analyzed in single-plaque isolate E of the insect baculovirus Autographa californica nuclear polyhedrosis virus (AcNPV). The 634-base-pair insertion is characterized by an 18-base-pair terminal inverted repeat and carries an EcoRI site. This additional EcoRI site in the 81-map-unit segment of the DNA of plaque isolate E of AcNPV explains the difference between the EcoRI restriction map of the DNA from this isolate and those of the virus stocks used in other laboratories. Except for this insertion, the nucleotide sequence at the site of insertion in the DNA of plaque isolate E is identical to that of AcNPV E2 (G. E. Smith and M. D. Summers, Virology 89:517-527, 1978). The cellular DNA insertion in the AcNPV genome is represented many times in the S. frugiperda cell genome but has no detectable homology with DNAs from species other than lepidopteran insects. In S. frugiperda cells, the transposonlike insertion sequences are transcribed into cytoplasmic RNA. The transcription of these sequences is initiated within the cellular insertion element. As reported previously (C. Oellig, B. Happ, T. Müller, and W. Doerfler, J. Virol. 61:3048-3057, 1987), in S. frugiperda cells infected with plaque isolate E of AcNPV, at least nine different size classes of AcNPV-specific RNAs are synthesized; in AcNPV E2-infected cells, similar size classes have been detected. The cellular insertion of plaque isolate E provides the initiation site for the synthesis of an additional RNA size class which is transcribed off viral DNA.

Overproduction of the protein encoded by the maize transposable element Ac in insect cells by a baculovirus vector

The polypeptide encoded in the Activator (Ac) element of Zea mays L. has been expressed in Spodoptera frugiperda insect cells using plasmids which carry the strong polyhedrin promoter of the baculovirus Autographa californica nuclear polyhedrosis virus (AcNPV). Recombinant AcNPVs with the Ac-cDNA integrated and under the control of the viral polyhedrin promoter have been isolated and their genomes have been partly characterized as to the location of the foreign DNA insert. Upon infection of S. frugiperda cells with the recombinant AcNPV, maize Ac element specific messenger RNAs, as well as a newly synthesized polypeptide with an apparent molecular weight of about 116 kDa, have been detected in extracts of recombinant infected cells. This polypeptide is absent from extracts of wild-type infected cells expressing the polyhedrin polypeptide which can be recognized by the presence of nuclear inclusion bodies. Recombinant infected cells lack this protein. The Ac specific polypeptide is detected by antisera, which have been raised against fusion proteins containing Ac sequences synthesized in Escherichia coli, both in immunoprecipitation and in Western blotting experiments. The Ac specific protein is a nuclear phosphoprotein and represents about 1%-2% of the newly synthesized protein.

Overlapping sets of viral RNAs reflect the array of polypeptides in the EcoRI J and N fragments (map positions 81.2 to 85.0) of the Autographa californica nuclear polyhedrosis virus genome

In several parts of the Autographa californica nuclear polyhedrosis virus (AcNPV) genome, nested sets of overlapping RNAs with common 3' or 5' termini have been recognized. In the present report, the pattern of viral transcription and the arrangement of viral gene products in the region of 81.2 to 85.0 map units were investigated. In this segment of the AcNPV genome, at least nine size classes of viral RNA were identified which ranged in size from 1.3 kilobases (kb) to 4.6 kb and exhibited common 3' termini. The detailed restriction map and the nucleotide sequence of this part of the AcNPV genome were determined. Computer analyses revealed several open reading frames (ORFs) on the rightward-transcribed strand with potential TATA and CAAT signals preceding many of the potential ORFs and the 5' termini of some of the mapped RNAs. The leftward-transcribed strand was devoid of major ORFs. The presumptive polypeptides encoded by the larger ORFs ranged in size from 11.3 to 55.6 kilodaltons (kDa). The amino acid sequence of the presumptive polypeptide encoded by ORF3, a 33.6-kDa molecule, exhibited an unusual, clustered 16-fold repeat of the dipeptide arginine-serine in a protein that showed an overall preponderance of basic amino acids. The results of in vitro translation experiments with hybrid-selected RNAs homologous to internal subfragments of the 81.2- to 85.0-map-unit region yielded polypeptides of approximately 28, 34 to 36, and 48 to 50 kDa, which were close in size to the lengths of the major ORFs derived from the nucleotide sequence. The localizations of individual size classes of RNAs in the 81.2- to 85.0-map-unit region of the viral genome were determined precisely at the 3' and 5' termini by S1 protection analyses. Within a sequence of eight nucleotides, all RNAs had the same 3' terminus, which lay close to multiple polyadenylation signals. The initiation sites of the nine different RNA size classes were precisely mapped. As the cap sites of the smaller RNAs (less than 1.8 kb) were determined by S1 protection analyses, a multitude of RNA initiation sites became apparent. It was also shown that the different RNA size classes in the 81.2- to 85.0-map-unit region were detectable as early as 2 h and at least until 36 to 48 h after infection. In unselected cytoplasmic RNA, the size classes of viral RNAs specific for the EcoRI J fragment were detectable early as well as late after infection, although at early times the larger RNAs were detectable in smaller amounts.(ABSTRACT TRUNCATED AT 400 WORDS)