The m6A reader ECT1 drives mRNA sequestration to dampen salicylic acid-dependent stress responses in Arabidopsis

N 6-methyladenosine (m6A) is a common epitranscriptional mRNA modification in eukaryotes. Thirteen putative m6A readers, mostly annotated as EVOLUTIONARILY CONSERVED C-TERMINAL REGION (ECT) proteins, have been identified in Arabidopsis (Arabidopsis thaliana), but few have been characterized. Here, we show that the Arabidopsis m6A reader ECT1 modulates salicylic acid (SA)-mediated plant stress responses. ECT1 undergoes liquid-liquid phase separation in vitro, and its N-terminal prion-like domain is critical for forming in vivo cytosolic biomolecular condensates in response to SA or bacterial pathogens. Fluorescence-activated particle sorting coupled with quantitative PCR analyses unveiled that ECT1 sequesters SA-induced m6A modification-prone mRNAs through its conserved aromatic cage to facilitate their decay in cytosolic condensates, thereby dampening SA-mediated stress responses. Consistent with this finding, ECT1 overexpression promotes bacterial multiplication in plants. Collectively, our findings unequivocally link ECT1-associated cytosolic condensates to SA-dependent plant stress responses, advancing the current understanding of m6A readers and the SA signaling network.

Cooperative role of AtRsmD and AtRimM proteins in modification and maturation of 16S rRNA in plastids

Chloroplast pre-ribosomal RNA (rRNA) undergoes maturation, which is critical for ribosome assembly. While the central and auxiliary factors in rRNA maturation have been elucidated in bacteria, their mode of action remains largely unexplored in chloroplasts. We now reveal chloroplast-specific factors involved in 16S rRNA maturation, Arabidopsis thaliana orthologs of bacterial RsmD methyltransferase (AtRsmD) and ribosome maturation factor RimM (AtRimM). A forward genetic screen aimed to find suppressors of the Arabidopsis yellow variegated 2 (var2) mutant defective in photosystem II quality control found a causal nonsense mutation in AtRsmD. The substantially impaired 16S rRNA maturation and translation due to the mutation rescued the leaf variegation phenotype by lowering the levels of chloroplast-encoded proteins, including photosystem II core proteins, in var2. The subsequent co-immunoprecipitation coupled with mass spectrometry analyses and bimolecular fluorescence complementation assay found that AtRsmD interacts with AtRimM. Consistent with their interaction, loss of AtRimM also considerably impairs 16S rRNA maturation with decelerated m² G915 modification in 16S rRNA catalyzed by AtRsmD. The atrimM mutation also rescued var2 mutant phenotypes, corroborating the functional interplay between AtRsmD and AtRimM towards modification and maturation of 16S rRNA and chloroplast proteostasis. The maturation and post-transcriptional modifications of rRNA are critical to assembling ribosomes responsible for protein translation. Here, we revealed that the cooperative regulation of 16S rRNA m² G915 modifications by AtRsmD methyltransferase and ribosome assembly factor AtRimM contributes to 16S rRNA maturation, ribosome assembly, and proteostasis in chloroplasts.

Impact of climate change induced future rainfall variation on dynamics of arid-humid zone transition in the western province of India

The transition of the Earth's climate from one zone to another is one of the major causes behind biodiversity loss, rural-urban migration, and increasing food crises. The rising rate of arid-humid zone transition due to climate change has been substantially visible in the last few decades. However, the precise quantification of the climate change-induced rainfall variation on the climate zone transition still remained a challenge. To solve the issue, the Representative Grid Location-Multivariate Adaptive Regression Spline (RGL-MARS) downscaling algorithm was coupled with the Koppen climate classification scheme to project future changes in various climate zones for the study area. It was observed that the performance of the model was better for the humid clusters compared to the arid clusters. It was noticed that, by the end of the 21^st century, the arid region would increase marginally and the humid region would rise by 24.28-36.09% for the western province of India. In contrast, the area of the semi-arid and semi-humid regions would decline for the study area. It was observed that there would be an extensive conversion of semi-humid to humid zone in the peripheral region of the Arabian sea due to the strengthening of land-sea thermal contrast caused by climate change. Similarly, semi-arid to arid zone conversion would also increase due to the inflow of dry air from the Arabian region. The current research would be helpful for the researchers and policymakers to take appropriate measures to reduce the rate of climate zone transition, thereby developing the socioeconomic status of the rural and urban populations.

EXECUTER2 modulates the EXECUTER1 signalosome through its singlet oxygen-dependent oxidation

Oxidative post-translational modifications of specific chloroplast proteins contribute to the initiation of retrograde signaling. The Arabidopsis thaliana EXECUTER1 (EX1) protein, a chloroplast-localized singlet oxygen (¹O₂) sensor, undergoes tryptophan (Trp) 643 oxidation by ¹O₂, a chloroplast-derived and light-dependent reactive oxygen species. The indole side chain of Trp is vulnerable to ¹O₂, leading to the generation of oxidized Trp variants and priming EX1 for degradation by a membrane-bound FtsH protease. The perception of ¹O₂ via Trp643 oxidation and subsequent EX1 proteolysis facilitate chloroplast-to-nucleus retrograde signaling. In this study, we discovered that the EX1-like protein EX2 also undergoes ¹O₂-dependent Trp530 oxidation and FtsH-dependent turnover, which attenuates ¹O₂ signaling by decelerating EX1-Trp643 oxidation and subsequent EX1 degradation. Consistent with this finding, the loss of EX2 function reinforces EX1-dependent retrograde signaling by accelerating EX1-Trp643 oxidation and subsequent EX1 proteolysis, whereas overexpression of EX2 produces molecular phenotypes opposite to those observed in the loss-of- function mutants of EX2. Intriguingly, phylogenetic analysis suggests that EX2 may have emerged evolutionarily to attenuate the sensitivity of EX1 toward ¹O₂. Collectively, these results suggest that EX2 functions as a negative regulator of the EX1 signalosome through its own ¹O₂-dependent oxidation, providing a new mechanistic insight into the regulation of EX1-mediated ¹O₂ signaling.

Homo- and Hetero-Dimers of CAD Enzymes Regulate Lignification and Abiotic Stress Response in Moso Bamboo

Lignin biosynthesis enzymes form complexes for metabolic channelling during lignification and these enzymes also play an essential role in biotic and abiotic stress response. Cinnamyl alcohol dehydrogenase (CAD) is a vital enzyme that catalyses the reduction of aldehydes to alcohols, which is the final step in the lignin biosynthesis pathway. In the present study, we identified 49 CAD enzymes in five Bambusoideae species and analysed their phylogenetic relationships and conserved domains. Expression analysis of Moso bamboo PheCAD genes in several developmental tissues and stages revealed that among the PheCAD genes, PheCAD2 has the highest expression level and is expressed in many tissues and PheCAD1, PheCAD6, PheCAD8 and PheCAD12 were also expressed in most of the tissues studied. Co-expression analysis identified that the PheCAD2 positively correlates with most lignin biosynthesis enzymes, indicating that PheCAD2 might be the key enzyme involved in lignin biosynthesis. Further, more than 35% of the co-expressed genes with PheCADs were involved in biotic or abiotic stress responses. Abiotic stress transcriptomic data (SA, ABA, drought, and salt) analysis identified that PheCAD2, PheCAD3 and PheCAD5 genes were highly upregulated, confirming their involvement in abiotic stress response. Through yeast two-hybrid analysis, we found that PheCAD1, PheCAD2 and PheCAD8 form homo-dimers. Interestingly, BiFC and pull-down experiments identified that these enzymes form both homo- and hetero- dimers. These data suggest that PheCAD genes are involved in abiotic stress response and PheCAD2 might be a key lignin biosynthesis pathway enzyme. Moreover, this is the first report to show that three PheCAD enzymes form complexes and that the formation of PheCAD homo- and hetero- dimers might be tissue specific.

FATTY ACID DESATURASE5 Is Required to Induce Autoimmune Responses in Gigantic Chloroplast Mutants of Arabidopsis

Chloroplasts mediate genetically controlled cell death via chloroplast-to-nucleus retrograde signaling. To decipher the mechanism, we examined chloroplast-linked lesion-mimic mutants of Arabidopsis (Arabidopsis thaliana) deficient in plastid division, thereby developing gigantic chloroplasts (GCs). These GC mutants, including crumpled leaf (crl), constitutively express immune-related genes and show light-dependent localized cell death (LCD), mirroring typical autoimmune responses. Our reverse genetic approach excludes any potential role of immune/stress hormones in triggering LCD. Instead, transcriptome and in silico analyses suggest that reactive electrophile species (RES) generated via oxidation of polyunsaturated fatty acids (PUFAs) or lipid peroxidation-driven signaling may induce LCD. Consistent with these results, the one of the suppressors of crl, dubbed spcrl4, contains a causative mutation in the nuclear gene encoding chloroplast-localized FATTY ACID DESATURASE5 (FAD5) that catalyzes the conversion of palmitic acid (16:0) to palmitoleic acid (16:1). The loss of FAD5 in the crl mutant might attenuate the levels of RES and/or lipid peroxidation due to the reduced levels of palmitic acid-driven PUFAs, which are prime targets of reactive oxygen species. The fact that fad5 also compromises the expression of immune-related genes and the development of LCD in other GC mutants substantiates the presence of an intrinsic retrograde signaling pathway, priming the autoimmune responses in a FAD5-dependent manner.

Quality by design approach for simultaneous estimation of doxycycline hyclate and curcumin by RP-HPLC method

A simple, rapid, reliable, robust and optimized reversed phase high performance liquid chromatographic method for simultaneous estimation of doxycycline hyclate and curcumin was successfully developed and validated as per International Conference on Harmonization guidelines. The objective was achieved in terms of well separated peaks within 10 min on a Waters Sunfire C8 column with dimensions of 250×4.6 mm, particle size 5.0 μm using mobile phase consisting of 30 volumes of potassium dihydrogen phosphate buffer (50 mM) adjusted to pH 6.5±0.1 with triethylamine and 70 volumes of methanol at flow rate of 0.85 ml/min. The column effluents were monitored at 400 nm maintained at ambient column temperature (28^o). The developed method was found linear over the concentration range of 200-700 μg/ml for doxycycline hyclate and 8-28 μg/ml for curcumin, the detection and quantitation limit was found to be 26.063 and 78.97 μg/ml for doxycycline hyclate; 0.795 and 2.13 μg/ml for curcumin, respectively. The developed method was optimized using Minitab software version 16 to meet the current quality by design requirements. The method validation was done for linearity, range, detection and quantitation limit, accuracy, precision, specificity, system suitability testing, and robustness.

Development and Validation of a RP-HPLC Method for Estimation of Prulifloxacin in Tablet Dosage Form

A simple, precise, rapid, accurate and economic reverse phase high performance liquid chromatographic method has been developed for the estimation of prulifloxacin in tablet dosage form. The separation was achieved by using octadecylsilane column (C₁₈) and KH₂PO₄ buffer: acetonitrile adjusted to pH 7.3 with triethyl amine in proportion of 10:90 v/v as mobile phase, at a flow rate of 1.0 ml/min. The detection was carried out at 278 nm. The retention time of prulifloxacin was found to be 2.4 min. The limit of detection and limit of quantitation were found to be 0.14 μg/ml and 0.42 μg/ml respectively. The accuracy and reliability of the proposed method was ascertained by evaluating various validation parameters like linearity, precision, accuracy and specificity according to ICH guidelines. The proposed method provides an accurate and precise quality control tool for routine analysis of prulifloxacin in tablet dosage form.

Development and Validation of a RP-Ultra performance liquid chromatographic Method for Quantification of Topotecan Hydrochloride in Bulk and Injection Dosage Form

A simple, very fast, precise and accurate reverse phase ultra performance liquid chromatographic method was developed for the determination and validation of topotecan hydrochloride in bulk and injection dosage form. A Waters BEH C18, 50×2.1 mm, 1.7 μm particle size column in gradient mode was used with mobile phase comprising of 0.1% v/v orthophosphoric acid in water and acetonitrile. The analytical column was thermostated at 50° and flow rate was set at 0.4 ml per min, with photo diode array detection at 260 nm. The retention time of topotecan was found 1.38 min. The method was validated in terms of linearity, accuracy, precision and specificity. The calibration curve was found linear between 20 to 60 μg/ml. The limit of detection and limit of quantification were found 0.2353 and 0.7131 μg/ml, respectively. Percentage recoveries were obtained in the range of 98.91% and 99.17%. The proposed method is precise, accurate, selective and reproducible. The ultra performance liquid chromatographic assay procedure, which proved superior because of its greater sensitivity and relatively shorter (4 min) run time, should be an important tool for speedy future analysis of topotecan hydrochloride in bulk and its injection dosage form.

pH-Induced In Situ Gel for Periodontal Anesthesia

A pH mediated in situ gelling system was developed using prilocaine hydrochloride for periodontal anesthesia using combination of chitosan and hydroxypropylmethylcellulose. The gel so developed can be used as anaesthetic in lengthy dental surgery. The gel was evaluated for many parameters like gelation pH, viscosity, physicochemical properties, in vitro release, sterility and stability. Gel with chitosan (0.25% w/v) and hydroxypropylmethylcellulose (0.25% w/v) was found to have good gelation near pH 7.4 (pH of mucous) with prolonged action.

Complete nucleotide sequence of cherry virus A (CVA) infecting sweet cherry in India

Cherry virus A (CVA) is a graft-transmissible member of the genus Capillovirus that infects different stone fruits. Sweet cherry (Prunus avium L; family Rosaceae) is an important deciduous temperate fruit crop in the Western Himalayan region of India. In order to determine the health status of cherry plantations and the incidence of the virus in India, cherry orchards in the states of Jammu and Kashmir (J&K) and Himachal Pradesh (H.P.) were surveyed during the months of May and September 2009. The incidence of CVA was found to be 28 and 13% from J&K and H.P., respectively, by RT-PCR. In order to characterize the virus at the molecular level, the complete genome was amplified by RT-PCR using specific primers. The amplicon of about 7.4 kb was sequenced and was found to be 7,379 bp long, with sequence specificity to CVA. The genome organization was similar to that of isolates characterized earlier, coding for two ORFs, in which ORF 2 is nested in ORF1. The complete sequence was 81 and 84% similar to that of the type isolate at the nucleotide and amino acid level, respectively, with 5' and 3' UTRs of 54 and 299 nucleotides, respectively. This is the first report of the complete nucleotide sequence of cherry virus A infecting sweet cherry in India.

Development and Validation of a RP-HPLC Method for Estimation of Montelukast Sodium in Bulk and in Tablet Dosage Form

The present work describes a simple, precise and accurate HPLC method for estimation of montelukast sodium in bulk and in tablet dosage form. The separation was achieved by using octadecylsilane column (C18) and acetonitrile:1 mM sodium acetate adjusted to pH 6.3 with acetic acid in proportion of 90:10 v/v as mobile phase, at a flow rate of 1.5 ml/min. Detection was carried out at 285 nm. The retention time of montelukast sodium was found to be 3.4 min. The limit of detection was found 1.31 µg/ml and limit of quantification 3.97 µg/ml. The accuracy and reliability of the proposed method was ascertained by evaluating various validation parameters like linearity (1-100 µg/ml), precision, accuracy and specificity according to ICH guidelines. The proposed method provides an accurate and precise quality control tool for routine analysis of montelukast sodium in bulk and in tablet dosage form.

Nodulation competitiveness between contrasting phage phenotypes of pigeonpea rhizobial strains

Competitiveness between (I) lysogenic vs. phage-indicator strains, (II) phage-resistant vs phage-sensitive strains, and (III) large plaque vs. small plaque developing strains was examined under laboratory and field conditions in order to study the involvement of these crucial phage sensitivity patterns in the competition for nodule occupancy of pigeonpea rhizobia. The phage-indicator strain (A039) exhibited higher competitiveness over the lysogenic strain (A025 Sm(r)); the phage sensitive strain (IHP-195) over the phage resistant strain (IHP 195 Sm(r)V(r)); and the large plaque developing strain (A059) over the small plaque developing strain (IHP195 Sm(r)) in association with pigeonpea cv. bahar both under laboratory and field conditions. Dual inoculation of A025 Sm(r) + A039 and A059 + IHP195 Sm(r) (mixed in equal proportion just before treatment) improved the nodule occupancy by inoculant strains against native rhizobia and resulted into higher plant dry weight and yield as compared to their application as single inoculum. The phage-resistant mutant IHP195 Sm(r)V(r) showed reduced competitiveness against native rhizobia, compared to its parental strain. The dual inoculation of parental strain and phage-resistant mutant gave the same result as the inoculation of parental strain alone.

Utility of intradermal smear in the diagnosis of malaria

The objective of this preliminary study was to evaluate the usefulness of the intradermal smear test in the diagnosis of malaria. One hundred cases of suspected malaria (having received no prior antimalarials) were investigated. Both peripheral blood film (PBF) and intradermal smears (IDS) were simultaneously prepared and patients placed on antimalarial therapy. The slides were repeated for the next 2 days. At admission, 70 cases were positive on PBF--59 were Plasmodium falciparum (PF) and 11 were Plasmodium vivax (PV) whereas surprisingly 62 cases were positive on IDS at admission--61 were PF, one was PV. IDS identified two more cases of PF [P value (not significant)] but failed to identify any new cases of PV (P value NS). On subsequent days IDS positivity for PF was higher than for PBF (P < 0.05 for day 1 and P < 0.001 for day 2). However, the PV yield was poor for any further statistical evaluation on subsequent days. We conclude that IDS is simple, easy to perform, requires no special infrastructure compared to PBF, and is a helpful diagnostic tool in cases where malaria is strongly suspected but peripheral blood slides are repeatedly negative due to prior use of antimalarial therapy. IDS may be added to routine PBF in malaria (especially PF).

Physiotherapists and human immunodeficiency virus/acquired immune deficiency syndrome: knowledge and prevention: a study in Durban, South Africa

This study determined what physiotherapists in Durban, South Africa know about human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS), their attitudes towards patients and how they cope as individuals. Data were collected using a validated questionnaire. One-hundred-and-fourteen physiotherapists in Durban hospitals participated in the study. Seventy-two per cent of the questionnaires met the criteria for analysis. Ninety per cent of the participants believed that they knew about HIV/AIDS, but only 78% could identify all viral transmission modes. Of the 38 physiotherapists who believed that they knew the stages of an HIV infection, only 11% actually knew the stages, 28% could not explain them and 61% were vaguely aware. Fifty-six per cent of the respondents had treated patients who had died from HIV/AIDS. Only 38% of physiotherapists were completely at ease when treating HIV/AIDS patients despite the fact that 98% believed that physiotherapy was an integral component of the management of an AIDS patient. Fifty-one per cent of the respondents were unaware of support structures provided by their employers. The authors conclude that the perceptions of physiotherapists about their knowledge about HIV/AIDS do not stand up to scrutiny. Significantly more attention should be paid to the development, implementation and evaluation of the effectiveness of educational programmes on HIV/AIDS for physiotherapists in the workplace.

Genetics of leaf blight resistance in wheat

Studies on the genetics of leaf blight caused byAlternaria triticina using generation mean analysis revealed that additive components played a major role, but that dominance components also contributed significantly in controlling the variability for leaf blight resistance in wheat crosses. Furthermore, the additive x additive type of epistasis was predominant in the first three crosses, whereas in the fourth cross additive x dominance (j) and dominance x dominance (1) components of epistasis were most significant. Because of this it may be desirable to follow a simple recurrent selection scheme for higher tolerance, to isolate resistant plants from the segregating populations derived from crosses of parents of diverse origin following the pedigree method of breeding. CPAN-1887 was very tolerant to leaf blight in the present study and should be utilized in hybridization programs to develop leaf-blight-resistant varieties.

Dose-dependent pharmacokinetics of N-5-dimethyl-9-[(2-methoxy-4-methylsulphonylamino)phenylamino]- 4-acridinecarboxamide (CI-921) in rabbits

N-5-dimethyl-9-[(2-methoxy-4-methylsulphonylamino)phenylamino]-4- acridinecarboxamide (CI-921), which is an analogue of amsacrine, has entered phase I clinical trials as an antitumour drug. The plasma pharmacokinetics of CI-921 has been studied in six rabbits after short i.v. infusions of 6.35, 12.7 and 25.4 mumol/kg. Total plasma concentrations of CI-921 were determined by a high-performance liquid chromatography method for up to 12 h post infusion. Comparison of pharmacokinetic parameters for each rabbit by within-subject analysis of variance indicated that with a four-fold increase in the dose from 6.35 to 25.4 mumol/kg there was a 44% increase in the area under the concentration-time curve normalised to dose (P less than 0.001) and a 43% increase in the elimination half-life (P less than 0.005), and a 30% decrease in the total plasma clearance (P less than 0.001). Dose had no effect on the end of infusion concentration normalised to dose, or on the steady-state volume of distribution. These results indicate that CI-921 experiences dose-dependent elimination kinetics in the rabbit.

The effect of buthionine sulphoximine, cimetidine and phenobarbitone on the disposition of amsacrine in the rabbit

Evidence suggests that the main elimination pathway for amsacrine is hepatic oxidation to the quinone diimine derivative followed by conjugation with glutathione (GSH) and excretion in the bile. If this is so, amsacrine elimination should be susceptible to induction by phenobarbitone (PB) and inhibition by cimetidine (CT) and perhaps by buthionine sulphoximine (BSO), a specific depleter of tissue GSH. This study was carried out in groups of six rabbits. Each rabbit acted as its own control and received pretreatment with saline or PB, CT, or BSO, followed by an amsacrine infusion. Blood (8 X 3 mL) was collected up to 12 h and total plasma amsacrine concentrations determined by HPLC. PB pretreatment resulted in a significant increase in amsacrine's Cl (mean 46%, range 25%-70%) and also in the Vd (mean 58%, range 25%-117%), but had no effect on t1/2 alpha, t1/2 beta or MRTni. In addition, there was no change in the plasma protein binding of amsacrine after PB pretreatment. CT pretreatment had the opposite effect, resulting in a significant decrease in amsacrine's Cl (mean 33%, range 21%-38%) and a decrease in Vd, although this latter decrease was not significant at the 5% level. As with PB, the time parameters were not significantly changed. BSO pretreatment resulted in a significantly reduced Cl (mean 22%, range 15%-30%), no effect on Vd or on t1/2 alpha, but significantly prolonged t1/2 beta and MRTni. BSO pretreatment was also associated with a significant reduction in red blood cell GSH concentration. These results are consistent with the involvement of the hepatic mixed function oxidase system and GSH status in the elimination of amsacrine in the rabbit.

Transmission of primary trisomics in pearl millet

Transmission rates of extra chromosomes found in the full set of trisomics of pearl millet (Pennisetum americanum) (2n = 14) were estimated by examining the progeny of selfed trisomics and the progeny of trisomics crossed to disomics. When the trisomics were selfed, 'dark green' and 'tiny' had the highest transmission rate (23.8% and 23.3%, respectively) and 'pseudonormal' the lowest (13.8%). Other trisomics had an intermediate rate of transmission. When the trisomics were used as females in crosses with disomics, both 'dark green' and 'tiny' again had the highest transmission rate and 'pseudonormal' the lowest. When the trisomics were used as males in crosses to disomics, no trisomic was transmitted to the progeny except for 'spindle', and this occurred with a very low frequency (2.0%). A variation in transmission rate was observed from plant to plant and season to season for the same trisomic type. A study of the transmission rate of the extra chromosomes indicated that the following factors were probably contributing to the lower rate of transmission: small- or light-weight seeds tended to have a higher proportion of trisomics than heavier seeds; lighter seeds had a lower percentage germination; a positive and significant correlation was noticed between trivalent frequency and transmission rate. Plants with reduced vigour produced a higher frequency of trisomics. Though trisomics involving longer extra chromosomes showed a high degree of pollen and ovule sterility, they were highly transmissible. This has resulted in a close relationship between gametic sterility and transmission rate of extra chromosome.

Divergent gene pools in rice improvement

The objective of the present study was to investigate the genetic architecture of yield in diverse populations of rice. Multivariate analysis by Mahalanobis's D(2) statistic and canonical (vector) analysis revealed that panicle weight, days to maturity, plant height and seed size were the important forces contributing towards divergence. One hundred rice strains were grouped into nine clusters with the help of D(2) and canonical analysis. The grouping pattern of the varieties were quite at random indicating that the geographical and genetic diversity were not related.

Tertiary trisomics of pearl millet (Pennisetum americanum (L.) K. Schum): its cytomorphology, fertility and transmission

Nineteen tertiary trisomics were isolated from some translocation heterozygotes and interchange trisomics of pearl millet. Cytological analysis of these trisomics indicates that chromosome association of trivalents, univalents and pentavalents were frequent in all the trisomics. But their ratio varied from one trisomic to the next. Other associations were relatively infrequent. The relative frequencies of 6 pentavalent configurations observed in different trisomics were studied and their probable association with mode of fertility and transmission rates have been discussed.

Assignment of configurations to adducts of 2-substituted anthracene with maleic anhydride by N.M.R. spectroscopy

Isomeric adducts of 2-methylanthracene and maleic anhydride and of 2-aminoanthracene and maleic anhydride were prepared and their configurations determined by N.M.R. spectroscopy. The adducts were transformed into their N-aminoimide derivatives. N'-Substituents on the amino group were chosen so as to permit, because of their restricted rotation and non-planarity about the N-N' bond, an investigation into the magnetic effects of the cage moiety. When both the dienyl parts of the Diels-Alder adducts are almost identical, the N'-acetyl-N'-phenyl group has been found to be a diagnostic probe for the configurational studies. In N-(N'-acetyl-N'-aroy1amino)imide derivatives, the N'-aroyl group has been found to prefer an anti conformation while in the N?-acetyl- N'-phenyl group the N'-phenyl prefers the syn conformation.

Role of carbon and nitrogen sources in bacterial growth and sporulation

A simple growth medium is reported, in which Bacillus megaterium forms heat-stable spores, heat-labile spores, or only vegetative cells by changing the carbon and nitrogen source. Studies carried out in such media could be very useful in elucidating biochemical events which lead to bacterial sporulation.