Zinc oxide and ferric oxide nanoparticles combination increase plant growth, yield, and quality of soybean under semiarid region

Zinc (Zn) and iron (Fe) malnutrition are global health challenges that need immediate attention. Hence, to address these issues, a two-pronged approach involving the development and application of novel Zn and Fe products for crop fertilization may be a potential solution. Therefore, zinc oxide (ZnO) (∼13.2 nm) and ferric oxide (Fe2O3) (∼15 nm) nanoparticles (NPs) were synthesized and characterized. Seven nutrients treatments viz, control, ZnO- NPs (25 mg kg-1), Fe2O3-NPs (25 mg kg-1), ZnO + Fe2O3-NPs (25 mg kg-1each), ZnSO4 (55.8 mg kg-1), FeSO4 (60.4 mg kg-1) and ZnSO4+ FeSO4 (55.8 and 60.4 mg kg-1) were arranged in five-time replicated Completely Randomized Design model to test the effectiveness of ZnO and Fe2O3 NPs in two soybean cultivars over conventional zinc sulfate (ZnSO4) and ferrous sulfate (FeSO4) fertilizers. The results indicated that the photosynthetic rate (Pn) and chlorophyll content increased (33.9-86.2%) significantly at the flowering stage with ZnO and Fe2O3 NPs applications, compared to their conventional counterparts. Likewise, the combined application of ZnO and Fe2O3 NPs reduced H2O2 production by 17-19% and increased the superoxide dismutase (SOD) and catalase (CAT) activities by 15-17% and 9.6-11.4% over the combined use of ZnSO4 and FeSO4, respectively. The normalized difference vegetation index (NDVI) showed an increase of 6.9-44.2% under ZnO and Fe2O3 NPs, as well as ZnSO4 and FeSO4. Furthermore, the combined application of NPs enhanced soybean seed yield by 4.6-18.3% compared to conventional Zn and Fe fertilizers. Concerning seed Zn and Fe density, conjoint application of ZnO and Fe2O3 NPs increases Zn by 1.8-2.2-fold and Fe by 19.22-22.58% over the combined application of Zn SO4 and FeSO4, respectively. While the application of NPs significantly decreased seed phytic acid concentrations by 7.3-59.9% compared to the control. These findings suggest that the combined application of ZnO and Fe2O3 NPs effectively enhances soybean productivity, seed nutrient density, and overall produce quality. Therefore, the combined application of ZnO and Fe2O3 -NPs in soybean can be a potential approach for sustainable soybean production and to reduce/arrest Zn and Fe malnutrition in a growing population.

Molecular and biological characterization of soybean yellow mottle mosaic virus severe strain infecting soybean in India

The complete nucleotide sequence and genome organization of soybean yellow mottle mosaic virus severe strain causing bright yellow mosaic, mottling and puckering symptoms in soybean (Glycine max) from India was determined. The monopartite single stranded genomic RNA is 3974 nuclotides long and has the potential to encode six viral proteins viz., p25, p83, p8, p10, p39 and p25. The SYMMV-Sb isolate differed from mungbean strain with 69 nucleotides and nine aminoacids dispersed over the various ORFs. Comparative sequence analysis revealed that SYMMV-Sb shared 98% nt sequence identity at complete genome level and 96-100% at all ORFs level with SYMMV mungbean strain from India and 71-92% identity with SYMMV Korean soybean isolate, whereas it showed very low sequence identity with other tombusviridae members (2-53%). The phylogenetic analysis showed the clustering of SYMMV-Sb along with other members of genus Gammacarmovirus. The SYMMV-Sb isolate produced chlorotic blotches, mild and veinal mottling, necrosis and puckering symptoms in various leguminous host plants. The symptomatalogy of the soybean isolate was differed from mungbean strain as earlier induced severe symptoms on soybean and mild symptoms on mungbean.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-02925-2.

AML1 protein interacts with influenza A virus neuraminidase and upregulates IFN-β response in infected mammalian cells

Neuraminidase (NA) is an integral membrane protein of influenza A virus (IAV) and primarily aids in the release of progeny virions, following the intracellular viral replication cycle. In an attempt to discover new functions of NA, we conducted a classical yeast two-hybrid screen and found acute myeloid leukaemia marker 1 (AML1) as a novel interacting partner of IAV-NA. The interaction was further validated by co-immunoprecipitation in IAV-infected cells and in an in vitro coupled transcription/translation system. Interestingly, we found an increase in the expression of AML1 upon IAV infection in a dose-dependent manner. As expected, we also observed an increase in the IFN-β levels, the first line of defence against viral infections. Subsequently, when AML1 was downregulated using siRNA, the IFN-β levels were found to be remarkably reduced. Our study also shows that AML1 is induced upon IAV infection and results in the induction of IFN-β. Thus, AML1 is proposed to be an important player in IFN induction and has a role in an antiviral response against IAV infection. SIGNIFICANCE AND IMPACT OF THE STUDY: Influenza epidemics and pandemics are constant threats to human health. Development of antiviral therapeutics has focused on important and major IAV proteins as targets. However, the rate at which this virus mutates makes the task challenging. Thus, next-generation approaches aim at host cellular proteins that aid the virus in its replication. This study reports a new host-virus interaction, of acute myeloid leukaemia marker 1 (AML1) with influenza A neuraminidase (IAV-NA). We have found that this interaction has a direct effect on the upregulation of host IFN-β response. Further studies may lead to a greater understanding of this new innate defence pathway in infected cells.

Comparative Analysis of Tocopherol Biosynthesis Genes and Its Transcriptional Regulation in Soybean Seeds

Tocopherols composed of four isoforms (α, β, γ, and δ) and its biosynthesis comprises of three pathways: methylerythritol 4-phosphate (MEP), shikimate (SK) and tocopherol-core pathways regulated by 25 enzymes. To understand pathway regulatory mechanism at transcriptional level, gene expression profile of tocopherol-biosynthesis genes in two soybean genotypes was carried out, the results showed significantly differential expression of 5 genes: 1-deoxy-d-xylulose-5-P-reductoisomerase (DXR), geranyl geranyl reductase (GGDR) from MEP, arogenate dehydrogenase (TyrA), tyrosine aminotransferase (TAT) from SK and γ-tocopherol methyl transferase 3 (γ-TMT3) from tocopherol-core pathways. Expression data were further analyzed for total tocopherol (T-toc) and α-tocopherol (α-toc) content by coregulation network and gene clustering approaches, the results showed least and strong association of γ-TMT3/tocopherol cyclase (TC) and DXR/DXS, respectively, with gene clusters of tocopherol biosynthesis suggested the specific role of γ-TMT3/TC in determining tocopherol accumulation and intricacy of DXR/DXS genes in coordinating precursor pathways toward tocopherol biosynthesis in soybean seeds. Thus, the present study provides insight into the major role of these genes regulating the tocopherol synthesis in soybean seeds.

Introgression of null allele of Kunitz trypsin inhibitor through marker-assisted backcross breeding in soybean (Glycine max L. Merr.)

BACKGROUND

Presence of Kunitz trypsin inhibitor (KTI) in soybean seeds necessitates pre-heat treatment of the soy-flour for its inactivation before using it in food and feed products. The heat treatment not only enhances processing costs of the soy-based foods and feeds but also affects seed-protein quality and solubility. Genetic elimination of KTI is an important and effective approach. Therefore, molecular marker-assisted backcross breeding (MABB) approach was adopted for genetic elimination of KTI from two popular soybean genotypes, DS9712 and DS9814. PI542044, an exotic germplasm line was used as donor of the kti allele which inhibits functional KTI peptide production.

RESULTS

Foreground selection for the kti allele was performed with three closely linked SSR markers while background selection was done with 93 polymorphic SSR markers. Plants in the BC1F1 generation were found to recover 70.4-87.63 % and 60.26-73.78 % of the recurrent parent genome (RPG) of DS9712 and DS9814, respectively. Similarly, selected plants in the BC2F1 generation had 93.01-98.92 % and 83.3-91.67 % recovery of their respective RPGs. Recombinant selection was performed so as to identify plants with minimal linkage drag. Biochemical analysis of the seeds of the selected plants (ktikti) confirmed absence of KTI peptides in the seeds. Phenotypically, the selected plants were comparable to the respective recurrent parent in yield and other traits.

CONCLUSIONS

MABB approach helped in speedy development of 6 KTI free breeding lines of soybean. Such lines will be suitable for the farmers and the soybean industries to use in production of soy-based foods and feeds without pre-heat treatment of the soy-flour. It would contribute towards wider acceptability of soy-based foods and feeds.

Nucleoprotein of influenza A virus negatively impacts antiapoptotic protein API5 to enhance E2F1-dependent apoptosis and virus replication

Apoptosis of host cells profoundly influences virus propagation and dissemination, events that are integral to influenza A virus (IAV) pathogenesis. The trigger for activation of apoptosis is regulated by an intricate interplay between cellular and viral proteins, with a strong bearing on IAV replication. Though the knowledge of viral proteins and mechanisms employed by IAV to induce apoptosis has advanced considerably of late, we know relatively little about the repertoire of host factors targeted by viral proteins. Thus, identification of cellular proteins that are hijacked by the virus will help us not only to understand the molecular underpinnings of IAV-induced apoptosis, but also to design future antiviral therapies. Here we show that the nucleoprotein (NP) of IAV directly interacts with and suppresses the expression of API5, a host antiapoptotic protein that antagonizes E2F1-dependent apoptosis. siRNA-mediated depletion of API5, in NP-overexpressed as well as IAV-infected cells, leads to upregulation of apoptotic protease activating factor 1 (APAF1), a downstream modulator of E2F1-mediated apoptosis, and cleavage of caspases 9 and 3, although a reciprocal pattern of these events was observed on ectopic overexpression of API5. In concordance with these observations, annexin V and 7AAD staining assays exhibit downregulation of early and late apoptosis in IAV-infected or NP-transfected cells on overexpression of API5. Most significantly, while overexpression of API5 decreases viral titers, cellular NP protein as well as mRNA levels in IAV-infected A549 cells, silencing of API5 expression causes a steep rise in the same parameters. From the data reported in this manuscript, we propose a proapoptotic role for NP in IAV pathogenesis, whereby it suppresses expression of antiapoptotic factor API5, thus potentiating the E2F1-dependent apoptotic pathway and ensuring viral replication.

Molecular analysis of soybean varying in water use efficiency using SSRs markers

A set of 91 soybean germplasm lines, collected from different parts of the world, were screened for Water Use Efficiency (WUE) using Carbon Isotope Discrimination (CID) technique and were characterized for 10 quantitative traits. After screening under field condition, 44 soybean genotypes showed variations in WUE. Molecular diversity of these 44 diverse soybean lines was carried out with 26 Simple Sequence Repeats (SSRs) markers, of which 10 were polymorphic (38.47% polymorphism). 28 alleles were observed which were distributed over 10 loci, with an average of 2.8 alleles per locus. Polymorphism Information Content (PIC) value of 10 polymorphic markers ranged from 0.40 (locus Satt460) to 0.67 (locus satt260), with an average of 0.46. Pair-wise genetic similarity value, as calculated by simple matching coefficient, ranged from 0.99 to 0.40, with an average of 0.70. Genotypes were clustered using NTSYS-pc software employing unweighted paired group method using arithmetic averages to generate the dendrogram. Dendrogram exhibited 8 distinct clusters with a similarity coefficient of 0.69. Genotypes having low to medium and medium to high CID value were clustered in distant groups indicating usefulness of these polymorphic SSRs markers for differentiating genotypes on the basis of their CID value. The findings of this study indicate the need for broadening genetic base of the present Indian soybean cultivars through use of exotic sources of variation towards WUE. Thus, diverse genotypes identified in this study would be beneficial to soybean breeders to develop mapping population to identify QTLs for WUE.

The nucleoprotein of influenza A virus induces p53 signaling and apoptosis via attenuation of host ubiquitin ligase RNF43

The interplay between influenza virus and host factors to support the viral life cycle is well documented. Influenza A virus (IAV) proteins interact with an array of cellular proteins and hijack host pathways which are at the helm of cellular responses to facilitate virus invasion. The multifaceted nature of the ubiquitination pathway for protein regulation makes it a vulnerable target of many viruses including IAV. To this end we conducted a yeast two-hybrid screen to search for cellular ubiquitin ligases important for influenza virus replication. We identified host protein, RING finger protein 43 (RNF43), a RING-type E3 ubiquitin ligase, as a novel interactor of nucleoprotein (NP) of IAV and an essential partner to induce NP-driven p53-mediated apoptosis in IAV-infected cells. In this study, we demonstrate that IAV leads to attenuation of RNF43 transcripts and hence its respective protein levels in the cellular milieu whereas in RNF43 depleted cells, viral replication was escalated several folds. Moreover, RNF43 polyubiquitinates p53 which further leads to its destabilization resulting in a decrease in induction of the p53 apoptotic pathway, a hitherto unknown process targeted by NP for p53 stabilization and accumulation. Collectively, these results conclude that NP targets RNF43 to modulate p53 ubiquitination levels and hence causes p53 stabilization which is conducive to an enhanced apoptosis level in the host cells. In conclusion, our study unravels a novel strategy adopted by IAV for utilizing the much conserved ubiquitin proteasomal pathway.

Mapping of yellow mosaic virus (YMV) resistance in soybean (Glycine max L. Merr.) through association mapping approach

Yellow Mosaic Virus (YMV) is a serious disease of soybean. Resistance to YMV was mapped in 180 soybean genotypes through association mapping approach using 121 simple sequence repeats (SSR) and four resistance gene analogue (RGA)-based markers. The association mapping population (AMP) (96 genotypes) and confirmation population (CP) (84 genotypes) was tested for resistance to YMV at hot-spot consecutively for 3 years (2007-2009). The genotypes exhibited significant variability for YMV resistance (P < 0.01). Molecular genotyping and population structure analysis with 'admixture' co-ancestry model detected seven optimal sub-populations in the AMP. Linkage disequilibrium (LD) between the markers extended up to 35 and 10 cM with r2 > 0.15, and >0.25, respectively. The 4 RGA-based markers showed no association with YMV resistance. Two SSR markers, Satt301 and GMHSP179 on chromosome 17 were found to be in significant LD with YMV resistance. Contingency Chi-square test confirmed the association (P < 0.01) and the utility of the markers was validated in the CP. It would pave the way for marker assisted selection for YMV resistance in soybean. This is the first report of its kind in soybean.

Changes in the levels of off-flavor generation in soybean through biotic elicitor treatments

The nutritional benefits of soybean remain underutilized as the off-flavor present in it limits the consumption and acceptability among people. The aim of the present study was to unveil the effect of the phytohormones methyl jasmonate (MJ: 0, 50 μM, 1 mM, and 15 mM) and salicylic acid (SA: 0, 50 μM, 0.1 mM, and 10 mM) as elicitors on two contrasting off-flavor soybean varieties at different growth stages (1, bloom; 2, pod development; 3, seed development). The effects of two elicitors varied widely and were found to be dose dependent and growth stage independent. SA reduces the lipoxygenase (LOX) and hydroperoxide lyase (HPL) activity, which in turn resulted in reduction in the TBA number and carbonyl value in contrast to MJ. SA 0.1 mM is the most effective dose in reduction of off-flavor determining parameters and protein oxidation, and it reduces the LOX and HPL activity by 2.3- and 2.4-fold, respectively in "high off-flavor" cultivar 'Bragg' compared to "low off-flavor" cultivar 'DS 2706' which showed 1.4- and 2.1-fold, respectively. This reduction in protein oxidation is also supported by enhanced content of antioxidant enzymes. Thus, phytohormone SA can be used in reduction of off-flavor generation, more effectively than MJ treatments, in soybean.

Population structure and association mapping studies for important agronomic traits in soybean

The present study was carried out with a set of 96 diverse soybean genotypes with the objectives of analysing the population structure and to identify molecular markers associated with important agronomic traits. Large phenotypic variability was observed for the agronomic traits under study indicating suitability of the genotypes for association studies. The maximum values for plant height, pods per plant, seeds per pod, 100-seed weight and seed yield per plant were approximately two and half to three times more than the minimum values for the genotypes. Seed yield per plant was found to be significantly correlated with pods per plant (r = 0.77), 100-seed weight (r = 0.35) and days to maturity (r = 0.23). The population structure studies depicted the presence of seven subpopulations which nearly corresponded with the source of geographical origin of the genotypes. Linkage disequilibrium (LD) between the linked markers decreased with the increased distance, and a substantial drop in LD decay values was observed between 30 and 35 cM. Genomewide marker-traits association analysis carried out using general linear (GLM) and mixed linear models (MLM) identified six genomic regions (two of them were common in both) on chromosomes 6, 7, 8, 13, 15 and 17, which were found to be significantly associated with various important traits viz., plant height, pods per plant, 100-seed weight, plant growth habit, average number of seeds per pod, days to 50% flowering and days to maturity. The phenotypic variation explained by these loci ranged from 6.09 to 13.18% and 4.25 to 9.01% in the GLM and MLM studies, respectively. In conclusion, association mapping (AM) in soybean could be a viable alternative to conventional QTL mapping approach.

Identification of a major QTL allele from wild soybean (Glycine soja Sieb. & Zucc.) for increasing alkaline salt tolerance in soybean

Salt-affected soils are generally classified into two main categories, sodic (alkaline) and saline. Our previous studies showed that the wild soybean accession JWS156-1 (Glycine soja) from the Kinki area of Japan was tolerant to NaCl salt, and the quantitative trait locus (QTL) for NaCl salt tolerance was located on soybean linkage group N (chromosome 3). Further investigation revealed that the wild soybean accession JWS156-1 also had a higher tolerance to alkaline salt stress. In the present study, an F(6) recombinant inbred line mapping population (n = 112) and an F(2) population (n = 149) derived from crosses between a cultivated soybean cultivar Jackson and JWS156-1 were used to identify QTL for alkaline salt tolerance in soybean. Evaluation of soybean alkaline salt tolerance was carried out based on salt tolerance rating (STR) and leaf chlorophyll content (SPAD value) after treatment with 180 mM NaHCO(3) for about 3 weeks under greenhouse conditions. In both populations, a significant QTL for alkaline salt tolerance was detected on the molecular linkage group D2 (chromosome 17), which accounted for 50.2 and 13.0% of the total variation for STR in the F(6) and the F(2) populations, respectively. The wild soybean contributed to the tolerance allele in the progenies. Our results suggest that QTL for alkaline salt tolerance is different from the QTL for NaCl salt tolerance found previously in this wild soybean genotype. The DNA markers closely associated with the QTLs might be useful for marker-assisted selection to pyramid tolerance genes in soybean for both alkaline and saline stresses.

Sample size for collecting germplasms--a polyploid model with mixed mating system

The present paper discusses a general expression for determining the minimum sample size (plants) for a given number of seeds or vice versa for capturing multiple allelic diversity. The model considers sampling from a large 2 k-ploid population under a broad range of mating systems. Numerous expressions/results developed for germplasm collection/regeneration for diploid populations by earlier workers can be directly deduced from our general expression by assigning appropriate values of the corresponding parameters. A seed factor which influences the plant sample size has also been isolated to aid the collectors in selecting the appropriate combination of number of plants and seeds per plant. When genotypic multiplicity of seeds is taken into consideration, a sample size of even less than 172 plants can conserve diversity of 20 alleles from 50,000 polymorphic loci with a very large probability of conservation (0.9999) in most of the cases.

A liquid synchronized-growth culture assay for the identification of true positive and negative yeast three-hybrid transformants

AIMS

To develop a simple and easy-to-use assay for detection of truely positive transformants from a yeast three-hybrid assay.

METHODS AND RESULTS

The yeast three-hybrid system is a new powerful system for studying RNA-protein interactions in vivo. There are, however, many reports from investigators about the difficulty in distinguishing a positive from a negative result due to the hard-to-detect differences between truely positive transformants and the negative ones. A liquid synchronous-growth culture approach has been described for all positive and negative transformants and their growth densities have been compared to each other at fixed intervals of incubation times. We have designed a simple yet effective procedure to assay for positive and negative RNA-protein interactions based on liquid culture analysis of synchronously growing yeast cells. Results obtained from this new procedure clearly show differences in positive and negative transformants after a 24-h incubation of synchronously growing transformants in liquid culture.

CONCLUSIONS

The procedure mentioned in this report shows clearly the differences between positive and negative results from a three-hybrid system.

SIGNIFICANCE AND IMPACT OF THE STUDY

The method proposed here is a clear advantage over existing methods based on measuring growth on restrictive growth medium plates by the naked eye. This method will have substantial usage with investigators using the yeast three-hybrid studies for RNA-protein interactions.

The ORF3 protein of hepatitis E virus binds to Src homology 3 domains and activates MAPK

The hepatitis E virus (HEV) is the causative agent of hepatitis E, an acute form of viral hepatitis. The biology and pathogenesis of HEV remain poorly understood. We have used in vitro binding assays to show that the HEV ORF3 protein (pORF3) binds to a number of cellular signal transduction pathway proteins. This includes the protein tyrosine kinases Src, Hck, and Fyn, the p85alpha regulatory subunit of phosphatidylinositol 3-kinase, phospholipase Cgamma, and the adaptor protein Grb2. A yeast two-hybrid assay was used to further confirm the pORF3-Grb2 interaction. The binding involves a proline-rich region in pORF3 and the src homology 3 (SH3) domains in the cellular proteins. Competition assays and computer-assisted modeling was used to evaluate the binding surfaces and interaction energies of the pORF3.SH3 complex. In pORF3-expressing cells, pp60(src) was found to associate with an 80-kDa protein, but no activation of the Src kinase was observed in these cells. However, there was increased activity and nuclear localization of ERK in the pORF3-expressing cells. These studies suggest that pORF3 is a viral regulatory protein involved in the modulation of cell signaling. The ORF3 protein of HEV appears to be the first example of a SH3 domain-binding protein encoded by a virus that causes an acute and primarily self-limited infection.

The full-length and N-terminal deletion of ORF2 protein of hepatitis E virus can dimerize

Hepatitis E virus is a human RNA virus containing three open reading frames. Of these ORF2 encodes, the major capsid protein (pORF2), may possess regulatory functions, in addition to a structural one. In this study, we have shown using the yeast two-hybrid system and in vitro immobilization experiments that full-length pORF2 is capable of self-association, thus forming a homodimer. Using mutational analysis we have studied dimerization of various truncated versions of the ORF2 capsid protein using the yeast two-hybrid system and supported our findings with in vitro immobilization experiments. Deletions of pORF2 reveal a loss of the dimerization potential for all deletions except an N-terminal 127-amino-acid deletion. Our studies suggest that the dimerization property of pORF2 may not be amino-acid sequence-dependent but instead a complex formation of a specific tertiary structure that imparts pORF2 its property to self-associate.

A yeast two-hybrid study on self-association of the ORF2 protein of hepatitis E virus

Hepatitis E virus is a human RNA virus containing three open reading frames. Of these, ORF2 encodes the major capsid protein (pORF2) and may possess regulatory functions, in addition to a structural one. In this study, we have shown using the yeast two-hybrid system and in vitro immobilization experiments that full-length pORF2 is capable of self-association, thus forming a homodimer. Using mutational analysis we have studied dimerization of various truncated versions of the ORF2 capsid protein using the yeast two-hybrid system and supported our findings with in vitro immobilization experiments. Deletions of pORF2 reveal a loss of the dimerization potential for all deletions except an N-terminal 127-amino-acid deletion. Our studies suggest that the dimerization property of pORF2 may not be amino-acid sequence dependent but instead a complex formation of a specific tertiary structure that imparts pORF2 its property to self-associate.

Self-association and mapping of the interaction domain of hepatitis E virus ORF3 protein

Hepatitis E virus (HEV) is a major human pathogen in the developing world. In the absence of an in vitro culture system, very little information on the basic biology of the virus exists. A small protein (approximately 13.5 kDa) of unknown function, pORF3, is encoded by the third open reading frame of HEV. The N-terminal region of pORF3 is associated with the cytoskeleton using one of its hydrophobic domains. The C-terminal half of pORF3 is rich in proline residues and contains a putative src homology 3 (SH3) binding domain and a mitogen-activated protein kinase phosphorylation site. In this study, we demonstrate that pORF3 can homodimerize in vivo, using the yeast two-hybrid system. We have isolated a 43-amino-acid interaction domain of pORF3 which is capable of self-association in vivo and in vitro. The overlap of the dimerization domain with the SH3 binding and phosphorylation domains suggests that pORF3 may have a dimerization-dependent regulatory role to play in the signal transduction pathway.

A critical review of the psychophysiology of driver fatigue

Driver fatigue is a major cause of road accidents and has implications for road safety. This review discusses the concepts of fatigue and provides a summary on psychophysiological associations with driver fatigue. A variety of psychophysiological parameters have been used in previous research as indicators of fatigue, with electroencephalography perhaps being the most promising. Most research found changes in theta and delta activity to be strongly linked to transition to fatigue. Therefore, monitoring electroencephalography during driver fatigue may be a promising variable for use in fatigue countermeasure devices. The review also identified anxiety and mood states as factors that may possibly affect driver fatigue. Furthermore, personality and temperament may also influence fatigue. Given the above, understanding the psychology of fatigue may lead to better fatigue management. The findings from this review are discussed in the light of directions for future studies and for the development of fatigue countermeasures.

Combined transformation and genetic technique verification of protein-protein interactions in the yeast two-hybrid system

The yeast two-hybrid system is frequently used to identify protein-protein interactions. The assay is based on the functional reconstitution of a transcriptional activator. Since an indirect phenotype of the positive clones is the basis for selection of positive interacting clones, the two-hybrid screens are vulnerable to false positives. Here we report a screening protocol based on the sequential use of the cotransformation approach followed by the genetic method for verifying true two-hybrid interactions. Using this procedure, we have screened a cDNA library and have been able to isolate true positives from the yeast two-hybrid screen.

Restoration of mRNA splicing by a second-site intragenic suppressor in the T4 ribonucleotide reductase (small subunit) self-splicing intron

The nrdB gene of bacteriophage T4 codes for the small subunit of ribonucleotide reductase and contains a 598-base self-splicing intron which is closely related to other group I introns of T4 and eukaryotes. Thirty-one mutants causing splicing defects in the nrdB intron were isolated. Twenty-three EMS-induced revertants for these 31 primary mutants were isolated by the strategic usage of the white halo plaque phenotype. We mapped these revertants by marker rescue using subclones of the nrdB gene. Some of these second-site mutations mapped to regions currently predicted by the secondary structure model of the nrdB intron. One of these suppressor mutants (nrdB753R) was found to be intragenic by marker rescue with the whole nrdB gene. However, this mutation failed to map within the nrdB intron. Splicing assays showed that this pseudorevertant restored splicing proficiency of the nrdB primary mutation to almost wild-type conditions. This is the first example of a mutation within the exons of a gene containing a self-splicing intron that is capable of restoring a self-splicing defect caused by a primary mutation within the intron. In addition, two other suppressor mutations are of interest (nrdB429R and nrdB399R). These suppressors were able to restore their primary 5' defect but in turn create a 3' splicing defect. Both of these revertants mapped in different regions of the intron with respect to their primary mutations.

Maize transposable element Ds is differentially spliced from primary transcripts in endosperm and suspension cells

The process by which transposable elements are spliced from the host gene transcripts remains poorly understood. We previously reported that a maize transposable element Ds (dissociation) and a copy of its host site duplication are perfectly spliced from the shrunken-2 transcript in the endosperm. Here, we have monitored splicing of the Ds element and its flanking Sh2 sequence following transient expression in maize suspension cells. The pattern of Ds splicing in suspension cells differs dramatically from that in the endosperm. In contrast to splicing in the endosperm, Ds in suspension cells was completely spliced from the transcripts using multiple donor and acceptor splice sites outside the element. In addition, noncanonical splice sites were utilized in suspension cells. Our results indicate that this difference in splicing is due to the context of Ds placement in the construct and/or to tissue specific differences in splicing.

The X gene of hepatitis B virus shows a high level stimulation of the Rous sarcoma virus long terminal repeat in the methylotropic yeast, Pichia pastoris

In order to study the transactivational property of the X gene in the methylotropic yeast Pichia pastoris, a Rous sarcoma virus-chloramphenicol acetyltransferase (RSV-CAT) cassette was co-transformed and integrated into the host yeast strain as a reporter which showed an overwhelming CAT activity. Immunoprecipitation of the yeast cell extracts with an X-specific monoclonal antibody, however, showed a low level expression of the X gene. Therefore besides a trans-effect of the X protein, the enhanced reporter activity could be a manifestation of a cis-effect of the X gene sequences also. Therefore, unlike the transactivation studies with X gene in animal cells where limited functional activity is observed, P. pastoris appears to be an excellent system to study cis- and trans-aspects of gene regulation by the X gene.

Differential regulation of enolase during anaerobiosis in maize

It was reported previously that enolase enzyme activity and ENO1 transcript levels are induced by anaerobic stress in maize (Zea mays). Here we show that not all isoforms of maize enolase are anaerobically induced. We cloned and sequenced a second enolase cDNA clone (pENO2) from maize. Sequence analysis showed that pENO2 shares 75.6% nucleotide and 89.5% deduced amino acid sequence identity with pENO1 and is encoded by a distinct gene. Expression of ENO2 is constitutive under aerobic conditions, whereas ENO1 levels are induced 10-fold in maize roots after 24 h of anaerobic treatment. Western-blot analysis and N-terminal sequencing of in vivo-labeled maize roots identified two major proteins selectively synthesized upon anaerobic stress as isozymes of enolase. We describe the expression of enolase in maize roots under anaerobic stress.

Effect of feedback signal and psychological characteristics on blood pressure self-manipulation capability

Blood pressure presentation mode and personality are likely to influence biofeedback outcome. Thirty-six normotensive subjects were randomly assigned to visual or auditory continuous systolic feedback. "Distracting speech" and "broad band noise" were also superimposed and the effect on the biofeedback response was investigated. Psychological influence was also investigated. Systolic pressure reduction of 4 +/- 4.3 mmHg (visual, p = .04) and 5 +/- 5.5 mmHg (visual + auditory, p = .03) were achieved compared with auditory feedback (2 +/- 4.7 mmHg), which was less effective. The addition of noise or speech had no effect on the systolic response, but speech adversely affected diastolic reduction (p = .04). Mood (p = .003) was associated with systolic lowering, whereas increased trait anxiety (p = .06) and expectation (p = .03) had trends for opposite effects. Increased anger-hostility, state-anxiety, and expectation (p = .06) had links with systolic raising capability. We conclude that feedback modality and psychological characteristics have implications for studies investigating blood pressure manipulation capability.

The effect of home training with direct blood pressure biofeedback of hypertensives: a placebo-controlled study

BACKGROUND

Home training in self-lowering of blood pressure using continuous blood pressure feedback has not previously been reported. Enhancement of laboratory-learned skills was hypothesized on the basis of outcomes from other intellectual, emotional and physical endeavours.

OBJECTIVE

To examine the supplementary effect of home blood pressure biofeedback training.

DESIGN

Thirty unmedicated, mild hypertensives participated in a randomized, double-blinded, modified contingency placebo-controlled study.

METHOD

After suitable screening and baseline blood pressure measurements subjects undertook eight laboratory biofeedback sessions and then 12 home training sessions over 4 weeks using continuous finger blood pressure monitoring.

RESULTS

In the laboratory those being administered active therapy (n=16) lowered systolic pressures by 5 +/- 5.4 mmHg compared with a lowering of 4 +/- 4.2 mmHg with placebo (NS). During the fourth week at home lowering for the active group (11 +/- 8 mmHg) was greater than that with placebo (4 +/- 6.2 mmHg, P=0.017). Arm-cuff blood pressures were not statistically different for groups and with time but that of the active group was lower by 9 +/- 15.4/7 +/- 10.2 mmHg, which is a clinically relevant change, after home biofeedback.

CONCLUSIONS

The efficacy of self-lowering of systolic blood pressure in mild hypertensives by continuous feedback was enhanced by 6 mmHg with 4 weeks of practice at home. Standard arm-cuff blood pressure was reduced by a clinically relevant amount. The home environment proved cost effective for this 'high-tech' approach.

Isolation and characterization of EMS induced splicing defective point mutations within the intron of the nrdB gene of bacteriophage T4

The nrdB gene of bacteriophage T4 codes for the small subunit of ribonucleotide reductase and contains a 598-base-pair self-splicing intron which is closely related to other group I introns of T4 and eukaryotes. The screening, isolation, and mapping of 31 nrdB intron mutations were conducted by the strategic usage of the white halo phenotype exhibited by T4 mutants defective in dyhydrofolate reductase or thymidylate synthase. These intron mutations cluster towards the ends, mainly the 3' end, and show a defect in self-splicing. These mutations map in regions of conserved structural elements, thus supporting secondary structure predictions. A distinct pattern of clustering is observed with the highest number of mutations mapping within three of the smaller regions (A, C, and D) of the nrdB intron and no mutations mapping in the largest (B) region. The highest density of mutations mapped in the smallest region (C) of the intron, containing only 96 bases, thus showing a distinct pattern of clustering within the catalytic core.

Placebo-controlled biofeedback blood pressure effect in hypertensive humans

The role of biofeedback in blood pressure control remains ill-defined because of nonspecific (placebo) effects, small study numbers, and the technical limitations of continuous pressure feedback. Clarification of its potential is awaited by those seeking a nonpharmacological approach to blood pressure control. This study examines the capability for systolic pressure lowering of 5 mm Hg or more using continuous pressure feedback in a statistical sample of untreated, well-characterized, mildly hypertensive individuals. Subjects were randomized in a double-blind study to active or placebo biofeedback. Placebo consisted of a modified contingency approach, using a partial disguise based on a digital high pass filter with 15 elements. Blood pressure-lowering capability was assessed during two laboratory sessions. Continuous visual feedback resulted in 11 of 28 subjects on active treatment and 12 of 28 on placebo treatment lowering their systolic pressure by 5 mm Hg or more (11 +/- 5.6 and 12 +/- 8.4 mm Hg, respectively; P = NS). Prestudy pressure was well-matched (153 +/- 9/97 +/- 4 and 154 +/- 8/98 +/- 4 mm Hg, respectively). An initial small difference in diurnal profile did not change. These findings indicate that among mildly hypertensive individuals, almost half can lower systolic pressure at will for short periods. This capability is independent of the real or placebo nature of the feedback signal. We conclude that there is no specific short-term biofeedback pressure-lowering capability in hypertensive individuals. Further exploration is needed to determine whether specific components of the placebo effect can be delineated, whether personality characteristics influence the response, and whether further biofeedback training can alter the outcome.

Expression and characterization of the hepatitis E virus ORF3 protein in the methylotrophic yeast, Pichia pastoris

We have used the methylotrophic yeast, Pichia pastoris, to express the open reading frame 3 (ORF3) of the hepatitis E virus (HEV). The ORF3 gene codes for a 123-amino-acid protein that contains highly immunodominant epitopes and is a potentially useful diagnostic and immunoprophylactic antigen. The expressed protein showed positive on immunoblots probed against antibodies raised in rabbit and infected human patient sera. In order to optimize the ORF3 protein expression, we have examined the regulated expression of this protein and characterized it. Unlike its expression in E. coli, the ORF3 protein was present in both the soluble and insoluble fractions of the cell lysate. The expressed protein is not glycosylated and does not undergo any major processing in the host strain.

Functional and sequence analysis of splicing defective nrdB mutants of bacteriophage T4 reveal new bases and a new sub-domain required for group I intron self-splicing

The nrdB gene of bacteriophage T4 codes for the small subunit of ribonucleotide reductase and contains a 598 nuclelotide group 1 self splicing intron. In order to study the functional domains for self-splicing of this intron, 23 nrdB splicing defective intron mutants were analyzed for both sequence and functional changes. These mutants cluster towards the ends in regions of conserved structural elements of the intron. These 23 mutants have single base changes at 14 different sites. Interestingly two of these sites that seemed to map within the intron are actually located on the flanking exon sequences on both sides of the intron. A high frequency (4/12) of the mutation sites are in bases not thought to be base-paired in the standard model of group I intron structure. The mutation sites in pairing regions P3, P7, P8, P9 and between P6[3'] and P7[5'] are identical to changes found in the well studied td (encoding dTMP synthase) intron. However, five new mutation sites (S61, SL1, S29, SL11, SL196 and SL126) are unique to the nrdB intron and disrupt self-splicing. A mutation (S61) in the P7.1 pairing region is especially significant because no mutations have been found in this pairing, thus defining a new sub-domain essential for RNA splicing. Like the td intron, the mutation site in P9 of the nrdB intron is a hot spot for mutations, but unlike td, the nrdB intron does not show a mutational hot spot in the P6[5'] region. Our molecular dissection of the nrdB intron also supports the P9.0 and P10 pairings that have been postulated to help form a complex tertiary structure required to give the RNA sequence its catalytic activity: particularly 3' splice site selection, cleavage and exon ligation.

Experience with roxithromycin in visceral leishmaniasis in north Bihar

In search of an oral drug for Visceral Leishmaniasis, 54 cases of Kala-azar were treated with roxithromycin, an orally administrable drug at a dose of 300 mg twice daily for 21 days. Thirty-nine (86.7%) were responsive (cured), 11 (28.2%) relapsed. The results appeared equally or even more effective when compared to the sodium antimony gluconate in two recent trials in Kala-azar in almost same demographic pattern. A possible synergistic action of roxithromycin and SAG was explored. Toxicities of SAG and roxithromycin are compared and discussed. Further controlled trials are needed before it can be widely used as first line drug for Indian Kala-azar in the present epidemic.

Physiological influences on continuous finger and simultaneous intra-arterial blood pressure

Because of the clinical and experimental utility of continuous finger blood pressure measurements and the need for accuracy, we tested the performance of a new hydraulic device in 22 consecutive hypertensive subjects during physiological and pharmacological interventions. Ipsilateral brachial intra-arterial pressure was monitored during rest, Valsalva's maneuver, static handgrip, and mental arithmetic and after sublingual glyceryl trinitrate. In excess of 40,000 blood pressure values were analyzed. Average bias (intra-arterial minus finger blood pressure) was 8.2 +/- 17.0 mm Hg (mean +/- SD, P = NS) for systolic and 2.8 +/- 10.4 mm Hg (P = NS) for diastolic pressure. Two-way ANOVA of biases with subject and task factors showed a subject effect (P < .001). Intersubject and intrasubject standard deviations of bias were 13.8 and 9.8 mm Hg systolic and 8.7 and 5.7 diastolic, respectively. Linear drift (millimeters of mercury per minute) of finger pressure was greater (P < .001) for systolic than diastolic pressure during static exercise and math and after glyceryl trinitrate. Coefficients of determination for blood pressure ranged from 0.4 +/- 0.3 to 0.8 +/- 0.3 during the tasks. We conclude that (1) noninvasive finger blood pressure faithfully follows intra-arterial changes but with clinically relevant offsets, (2) this technique is best suited for assessing pressure changes, (3) physiological and pharmacological interventions do not consistently affect finger pressure accuracy, (4) many reports of finger blood pressure measuring devices are based on direct readings obtained with inadequate system response characteristics, and (5) the tested instrument falls short of the standard requirements (bias < or = 5 +/- 8 mm Hg) for devices that measure intermittently.

Continuous, non-invasive volume-clamp blood pressure: determinants of performance

OBJECTIVE

To test a prototype hydraulic, non-invasive, continuous finger blood pressure monitor based on the volume-clamp principle for procedure-related factors likely to influence precision.

DESIGN

The influence of these factors was determined by repeatability of finger blood pressure measurement and the relationship to contralateral arm-cuff blood pressure.

METHODS

Repeated blood pressure measurements from three different fingers were made in 60 subjects following re-initialization of the device and re-insertion of the finger into the cuff. Repeatability was assessed in relation to simultaneous arm-cuff readings. Drift in arm-finger discrepancy was measured over a 1-h period. Finger diameter, drug therapy and presence of peripheral vascular disease were correlated with arm-finger blood pressure difference.

RESULTS

Repeatability coefficients (twice the SD of the arm-finger difference) across device re-initialization were large, but similar to parallel repeated arm blood pressure determinations: 17.6 and 17.1 mmHg for systolic blood pressure (SBP) and 13.9 and 13.6 mmHg for diastolic blood pressure (DBP), respectively. Withdrawing and re-inserting the finger reduced repeatability substantially, with a 50% increase in repeatability coefficient. A trend towards a progressive 9-mmHg increase was observed in overestimation of SBP over the 1-h period. Mean +/- SD pooled arm-finger blood pressure differences were -10.8 +/- 14.6 mmHg for SBP and 4.5 +/- 9.4 mmHg for DBP. Blood pressure measured in different fingers was similar on average, with repeatability no poorer than for re-insertion of the same finger. The presence of peripheral vascular disease in 15 subjects correlated with a smaller arm-finger difference for DBP.

CONCLUSIONS

Variations in positioning of the finger within the cuff influences blood pressure measurement during volume-clamp plethysmography, reducing its precision. Finger SBP exceeds brachial auscultatory readings and has similar precision.

A novel approach for isolation and mapping of intron mutations in a ribonucleotide reductase encoding gene (nrdB) of bacteriophage T4 using the white halo plaque phenotype

The nrdB gene of bacteriophage T4 codes for the small subunit of ribonucleotide reductase and contains a 598 base pair self splicing intron which is closely related to other group I introns of T4 and eukaryotes. The screening, isolation and mapping of the nrbB intron mutations was conducted by the strategic usage of the white halo phenotype exhibited by T4 mutants defective in dhydrofolate reductase or thymidylate synthase. We have isolated 159 hydroxylamine-induced nrdB mutants, determined which mutations are in nrdB by marker rescue with clones of the nrdB gene and have mapped these mutations by marker rescue using subclones of the nrdB intron. Thirty out of the 159 nrdB mutations are in or near the intron. These mutations cluster towards the ends, mainly the 3' end. We have performed deletion mapping to further map mutations in the 3' end of the intron. The mutations map in regions of conserved structural elements, thus supporting secondary structure predictions similar to those of the well studied td intron in the T4 gene coding for thymidylate synthase.

Methylene blue and organised differentiation in the chick embryo

The sub-blastodermal administration of methylene blue at 17 h of incubation gives rise to a mosaic of neuroectodermal differentiation with a disruption of the neural axis at 40 h of incubation. These features appear to be due to the rapid and direct movement of this dye into all the cells of the chick embryo blastoderm, and its binding and breakdown of the cytoplasmic ribose nucleotides, due to which neural tube formation is completely inhibited. The findings are confirmed by combined copper sulphate and methylene blue treatment, as copper is a powerful catalyst of methylene blue activity and binds with RNA.

Adrenergic receptors in the hypothalamus concerned with control of arterial blood pressure: elicited by electrical and chemical stimulation

The study was made with the help of a chemitrode placed in various areas of the hypothalamus by the stereotaxic technique, for electrical and chemical stimulation (noradrenaline or isoprenaline) before and after microinjection of respective blockers (phenoxybenzamine or practalol). The results indicated the presence of both alpha and beta-adrenoreceptors in the anterior and dorsomedial hypothalamus producing a depressor response, and, the presence of alpha adrenoreceptors in the posterior and lateral hypothalamus producing a pressor response.

Metabolic problems in the management of a traumatic pancreatic fistula

A case of persistent, high output, traumatic pancreatic fistula, complicated by the development of a gastric fistula secondary to a pancreatic abscess, is described. The problems associated with the metabolic and nutritional management are discussed.

Variations of some plasma components after closed fractures

1) Variations in the serum concentrations of total proteins and the electrophoretic fractions, glycoprotein, mucoprotein, fibrinogen, erythrocyte sedimentation rate, calcium, phosphorus, alkaline, and acid phosphatases were analyzed until the 30th day following uncomplicated fracture of shafts of long bones of the limbs in 25 cases. 2) A significant fall of albumin with concomitant rise of alpha 1, alpha 2, and beta globulins were noted until 30th day. 3) Mucoprotein, glycoprotein, and fibrinogen showed parallel elevations with that of alpha and beta globulins. 4) The peak values of alpha 1 and alpha 2 globulins, mucoprotein, and fibrinogen were registered on the 10th day after trauma. Albumin showed maximum fall on the 10th day in all these cases. 5) Glycoprotein showed a peak value on the 5th day. 6) Total protein and gamma globulin remained almost unchanged throughout the studies. 7) Beta globulin showed higher values and paralleled more closely the fibrinogen and erythrocyte sedementation rates. 8) The elevations of beta globulin, fibrinogen, and erythrocyte sedimentation rate were higher, and persisted beyond 30 days in lower-limb fractures as compared to upper-limb fractures. 9) Serum calcium, phosphorus, alkaline phosphatase, and acid phosphatase were not significantly different following fractures and therefore did not reflect much physiologic variation. 10) The most significant changes in the levels of plasma fractions studied were conspicuous on the 10th day and lasted for about 1 month.

Effect of subdiaphragmatic vagotomy on production of gastric ulcers in pylorus-ligated albino rats

A reduction in volume and free and total acidity of gastric content was noted along with reduction in ulcer index, with a shift of the site of ulceration from fundus to the glandular part of the stomach, following vagotomy in pylorus-ligated rats. Low volume and acidity explains the absence of ulcers in the fundus, but the increased involvement of glandular part in ulceration is possibly due to weakening of the mucosal barrier following vagotomy.

Study of urinary volume and creatinine excretion in women medical students

The urine volume per 24 hours is much lower than that reported in literature and therefore, it is necessary to establish Indian base lines. The experiments have been done under three different weather conditions, the results suggest an extent of allowance to be made for interpreting the results of concentration of substances in urine. The daily creatinine excretion was much lower than that reported in Western literature. This may be of value when creatinine excretion is being used as a check for completeness of 24 hours urine volume in Indians.

Effect of cyproheptadine on feeding behaviour in albino rats

The effect of cyproheptadine on feeding behaviour was investigated in fasted albino rats with the help of a Skinner box. Cyproheptadine decreased the rate of bar-pressing under continuous reinforcement although it has been reported to be an appetite promoting drug.