Transfer of Ogu cytoplasmic male sterility to Brassica juncea and improvement of the male sterile line through somatic cell fusion

Male sterility conferred by ogu cytoplasm of Raphanus sativus has been transferred to Brassica juncea cv 'RLM 198' from male-sterile B. napus through repeated backcrossing and selection. The male-sterile B. juncea is, however, highly chlorotic and late. It has low female (seed) fertility and small contorted pods. To rectify these defects, protoplasts of the male sterile were fused with normal 'RLM 198' (green, self fertile). Four dark green, completely male-sterile plants were obtained and identified as putative cybrids. All the plants were backcrossed three times with 'RLM 198'. Mitochondrial and chloroplast DNA analysis of backcross progeny confirmed hybridity of the cytoplasm. The restriction pattern of the chloroplast DNA of progeny plants of three cybrids (Og 1, Og 2, Og 3) was similar to that of the green self-fertile 'RLM 198' and indicated that the correction of chlorosis resulted from chloroplast substitution. The chloroplast DNA of the lone progeny plant of the fourth cybrid (Og 10) could not be analyzed because the plant was stunted and had only a few leaves. When total cellular DNA was probed with mitochondrial probes coxI and atpA it was found that the cybrids had recombinant mitochondria. The chlorosis-corrected plants were early flowering and had vastly improved seed fertility.

Lethality in yeast of trichothiodystrophy (TTD) mutations in the human xeroderma pigmentosum group D gene. Implications for transcriptional defect in TTD

Mutations in the human XPD gene result in a defect in nucleotide excision repair of ultraviolet damaged DNA and cause the cancer-prone syndrome xeroderma pigmentosum (XP). Besides XP, mutations in XPD can cause another seemingly unrelated syndrome, trichothiodystrophy (TTD), characterized by sulfur-deficient brittle hair, ichthyosis, and physical and mental retardation. To ascertain the underlying defect responsible for TTD, we have expressed the TTD mutant proteins in the yeast Saccharomyces cerevisiae and determined if these mutations can rescue the inviability of a rad3 null mutation. RAD3, the S. cerevisiae counterpart of XPD, is required for nucleotide excision repair and also has an essential role in RNA polymerase II transcription. Expression of the wild type XPD protein or the XPD Arg-48 protein carrying a mutation in the DNA helicase domain restores viability to the rad3 null mutation. Interestingly, the XPD variants containing TTD mutations fail to complement the lethality of the rad3 null mutation, strongly suggesting that TTD mutations impair the ability of XPD protein to function normally in RNA polymerase II transcription. From our studies, we conclude that XPD DNA helicase activity is not essential for transcription and infer that TTD mutations in XPD result in a defect in transcription.

Requirement of the yeast RTH1 5' to 3' exonuclease for the stability of simple repetitive DNA

Simple repetitive DNA sequences are unstable in human colorectal cancers and a variety of other cancers. Mutations in the DNA mismatch repair genes MSH2, MLH1, and PMS1 result in elevated rates of spontaneous mutation and cause a marked increase in the instability of simple repeats. Compared with the wild type, a null mutation in the yeast RTH1 gene, which encodes a 5' to 3' exonuclease, was shown to increase the rate of instability of simple repetitive DNA by as much as 280 times and to increase the spontaneous mutation rate by 30 times. Epistasis analyses were consistent with the hypothesis that this RTH1-encoded nuclease has a role in the MSH2-MLH-1-PMS1 mismatch repair pathway.

Comparative activity of three repellents against bedbugs Cimex hemipterus (Fabr.)

Comparative activity of three repellents viz., diethyl-m-toluamide (DEET), diethyl phenyl-acetamide (DEPA) and dimethylphthalate (DMP) against bedbugs Cimex hemipterus (Fabr) was studied by applying repellent solution on the shaven skin of rabbits. DEET (Tech. grade) 20mgai/cm2 exhibited 93 and 83 per cent repellency after 2 and 8 h respectively, while DEPA (Tech. grade) at this concentration exhibited 90 and 71 per cent repellency. DEET and DEPA at 75 per cent concentration (15mgai/cm2) showed 85 and 78 per cent repellency up to 2 h and 52 and 42 per cent repellency 6 h after treatment respectively. The repellent activity was also found to be concentration and time of treatment dependent in respect of DEET and DEPA. DMP (Tech. grade) did not show any appreciable repellent activity at any concentration tested. Further, the blood intake by C. hemipterus following treatment with various concentrations of repellents was found to decrease with increase in the concentration of repellents.

Reconstitution of yeast nucleotide excision repair with purified Rad proteins, replication protein A, and transcription factor TFIIH

Nucleotide excision repair (NER) functions to remove DNA damage caused by ultraviolet light and by other agents that distort the DNA helix. The NER machinery has been conserved in structure and function from yeast to humans, and in humans, defective NER is the underlying cause of the cancer-prone disease xeroderma pigmentosum. Here, we reconstitute the incision reaction of NER in Saccharomyces cerevisiae using purified protein factors. The Rad14 protein, the Rad4-Rad23 complex, the Rad2 nuclease, the Rad1-Rad10 nuclease, replication protein A, and the RNA polymerase II transcription factor TFIIH were purified to near homogeneity from yeast. We show that these protein factors are both necessary and sufficient for dual incision of DNA damaged by either ultraviolet light or N-acetoxy-2-aminoacetylfluorene. Incision in the reconstituted system requires ATP, which cannot be substituted by adenosine 5'-O-(3-thiotriphosphate), suggesting that the hydrolysis of ATP is indispensable for the incision reaction. The excision DNA fragments formed as a result of dual incision are in the 24-27-nucleotide range.

Diplotaxis catholica + Brassica juncea somatic hybrids: molecular and cytogenetic characterization

Intergeneric somatic hybrids Diplotaxis catholica (2n=18) + Brassica juncea (2n=36) were produced by fusing mesophyll protoplasts of the former and hypocotyl protoplasts of the latter using polyethylene glycol. Out of 52 somatic embryos, 24 produced plants of intermediate morphology. Cytological analysis of 16 plants indicated that 15 were symmetric hybrids carrying 54 chromosomes, the sum of the parental chromosome numbers. One hybrid was asymmetric with 45 chromosomes. Nuclear hybridity of five putative hybrids was confirmed by the Southern hybridization pattern of full length 18s-25s wheat nuclear rDNA probe which revealed the presence of Hind III fragments characteristic of both the parental species. The hybridization pattern of mitochondria specific gene probe cox I indicated that three of the hybrids carried B. juncea mitochondria and one carried mitochondria of D. catholica. Presence of novel 3.5 kb Hind III and 4.8 kb Bgl II fragments suggested the occurrence of mtDNA recombination in one of the hybrids. The hybrids were pollen sterile. However, seeds were obtained from most of the hybrids by back crossing with B. juncea.

Plant uptake of fluoride in irrigation water by ladyfinger (Abelmorchus esculentus)

Because of suggestions that food is a rich source of fluoride to humans and the absence of permissible and upper limits of fluoride for irrigation water, plant uptake studies were conducted using fluoride-rich irrigation water. Ladyfinger was grown in sand and soil cultures for 18 wk and the accumulation of fluoride in various plant parts was studied. The potential for ingestion of fluoride by humans through this route was also considered. The percentage uptake was greater in sand-cultured plants than in soil-cultured plants. The root accumulates most of the fluoride supplied through irrigation water and the fruit accumulates the least. Up to 120 mg fluoride/litre of irrigation water did not harm the plants. The ingestion of fluoride by humans from plants irrigated with water containing 10 mg fluoride/litre would be 0.20 mg per 100 g ladyfinger.

Studies on uptake of trivalent and hexavalent chromium by maize (Zea mays)

Pot culture experiments were carried out to study the uptake and translocation of chromium from irrigation water when supplied in its trivalent and hexavalent states to maize plants grown in soil and sand culture. The uptake of chromium was observed to increase with increase in the concentration for both oxidation states of chromium. For the root, the observed order of uptake was CrIII sand > CrVI sand > CrIII soil > CrVI soil, whereas in the lower shoot, upper shoot and fruit the order was CrVI sand > CrVI soil > CrIII sand > CrIII soil. Significantly high uptake of chromium by roots in the sand culture (CrIII treatment) is attributed to the effect of root exudates and degradation products on the mobilization of CrIII. In aerial parts of the plants a higher uptake was observed when the initial supply was CrVI. The trends observed are explained on the basis of the redox behaviour of chromium.

Yeast DNA repair protein RAD23 promotes complex formation between transcription factor TFIIH and DNA damage recognition factor RAD14

In Saccharomyces cerevisiae, the multisubunit RNA polymerase II general transcription factor TFIIH is indispensable for transcription initiation and some of its subunits are known to be required for nucleotide excision repair (NER) of DNA damaged by ultraviolet light. RAD3, a subunit of TFIIH, binds UV-damaged DNA in an ATP-dependent manner. It has, however, remained unclear how TFIIH is assembled with the other damage recognition component RAD14. Here, we demonstrate a higher order complex consisting of TFIIH, RAD14, and another NER protein RAD23, and complex formation between TFIIH and RAD14 is facilitated by the RAD23 protein.

Ultrasound guided percutaneous fine needle aspiration cytology of pancreas: a review of 61 cases

The study includes 61 cases which were subjected to ultrasound (US) guided fine needle aspiration cytology (FNAC) to find out the utility of this technique in the diagnosis of pancreatic lesions. Age of the patients ranged from 23 to 85 years with a median of 50 years. Male to female ratio was 36:25. One or more clinical diagnoses were offered in 16 and in 9 of these, the disease was related to pancreas. Subsequent to US, the lesions were localized to pancreas in 57 and the nature of pathology in the pancreatic lesion could be diagnosed in 31. By FNAC, 31 cases (50.8%) were diagnosed to have pancreatic malignancy which included adenocarcinoma (23 cases), papillary cystic tumour (1), muco-epidermoid carcinoma (1), acinic cell carcinoma (1), islet cell tumor (1), and non Hodgkin lymphoma (4). FNAC of liver in 2 cases and retroperitoneal lymph node in a case of pancreatic adenocarcinoma revealed metastasis. During follow up, 1 case of non Hodgkin's lymphoma showed CSF involvement. Three cases (4.9%) were suspected to have epithelial malignancy of which one was confirmed as an adenocarcinoma following surgery and histology. Four (6.6%) were benign lesions which included nonspecific inflammation (2 cases), tuberculous pancreatitis (1) and pseudopancreatic cyst (1). The remaining 23 cases (37.7%) had normal or inadequate cytology. Of these, FNAC of liver showed metastasis in 2 cases and one case each were diagnosed as adenocarcinoma and pseudopancreatic cyst respectively following surgery. None of the patients had any complication following FNAC. We recommend US guided FNAC to be routinely used for diagnosis of pancreatic lesion.

Cloning and analysis of murine cDNA that encodes a fibrogenic lymphokine, fibrosin

Tissue fibrosis that complicates chronic inflammation can be a cause of serious morbidity. The molecular links between inflammation and fibrosis appear to be a variety of proteins produced by activated chronic inflammatory cells. Collectively, these fibrogenic cytokines promote the growth of fibroblasts and the production of extracellular matrix that are the characteristic features of fibrotic tissue. In an attempt to clone cDNA for a fibrogenic lymphokine that we had isolated, we transfected COS-7 cells with a cDNA library derived from concanavalin A-stimulated lymphocyte line CDC25. Conditioned medium from the transfected COS-7 cells but not from sham-transfected cells stimulates fibroblast proliferation in vitro. We used heterologous expression in COS-7 cells of pools of CDC25 cDNA and screening for biological activity in conditioned medium to enrich for the cDNA clone(s) that encodes this activity. With this strategy of sib selection we isolated clone 2B3. The culture supernatants of 2B3-transfected COS-7 cells exert maximum growth-stimulating effects on fibroblasts at a dilution of 1:20,000. The isolated cDNA has one open reading frame (216 nucleotides) that has no significant homology with nucleotide sequences that encode other proteins. A synthetic peptide constructed from the deduced amino acid sequence is biologically active in picomolar concentrations, even though it may represent only a portion of the native fibrosin. This lymphokine, which we designate fibrosin, may play a role in regulating fibrogenesis in certain chronic inflammatory diseases.

Conditional lethality of null mutations in RTH1 that encodes the yeast counterpart of a mammalian 5'- to 3'-exonuclease required for lagging strand DNA synthesis in reconstituted systems

A 5'- to 3'-exonuclease of about 45 kDa has been purified from various mammalian sources and shown to be required for the completion of lagging strand synthesis in reconstituted DNA replication systems. RTH1 encodes the yeast Saccharomyces cerevisiae counterpart of the mammalian enzyme. To determine the in vivo biological role of RTH1-encoded 5'- to 3'-exonuclease, we have examined the effects of an rth1 delta mutation on various cellular processes. rth1 delta mutants grow poorly at 30 degrees C, and a cessation in growth occurs upon transfer of the mutant to 37 degrees C. At the restrictive temperature, the rth1 delta mutant exhibits a terminal cell cycle morphology similar to that of mutants defective in DNA replication, and levels of spontaneous mitotic recombination are elevated in the rth1 delta mutant even at the permissive temperature. The rth1 delta mutation does not affect UV or gamma-ray sensitivity but enhances sensitivity to the alkylating agent methyl methanesulfonate. The role of RTH1 in DNA replication and in repair of alkylation damage is discussed.

Production of wide hybrids and backcross progenies between Diplotaxis erucoides and crop brassicas

Intergeneric hybrids were produced between D. erucoides (♀), a wild species, and four cultivated species of Brassica, B. campestris, B. juncea, B. napus and B. oleracea, through embryo rescue. The hybrid nature of these plants was confirmed through morphological and cytological studies. Backcross pollinations with the pollen of the respective cultivars yielded BC progenies in the hybrids D. erucoides x B. juncea and D. erucoides x B. napus but not in D. erucoides x B. campestris and D. erucoides x B. oleracea. The hybrid D. erucoides x B. campestris was also used as a bridge species and crossed with B. juncea to raise the hybrid and backcross progenies. F2 progenies were more amenable than f1 hybrids for raising backcross progenies. Although D. erucoides is considered to be a close relative of B. campestris and B. oleracea, incompatibility barriers of this species with different cultivars do not reflect this relationship.

A role for nongovernmental organizations in monitoring the iodine content of salt in northern India

The feasibility of using nongovernmental organizations (NGOs) to monitor the iodine content of salt was studied in Uttar Pradesh, northern India, where iodine-deficiency disorders (IDDs) are endemic. Three NGOs already involved in health and development activities in the Gorakhpur, Varanasi, and Dehradun regions collected salt samples monthly from households and shops in selected villages over a 6-month period. A total of 4001 samples were analysed at regional laboratories by trained personnel using a standard protocol; 10% of the samples were sent to a central laboratory for external quality control. The iodine content lay in the range 0-95 mg/kg of salt; it was particularly low in the Gorakhpur and Varanasi regions, where over 80% of samples contained less than the minimum recommended level of 15 mg/kg; 37% of samples were in this category in the Dehradun region. Regular monitoring of the iodine content of salt at the consumer level is essential for the elimination of IDDs, and there is a need to improve awareness of this at all levels. NGOs can play a valuable role in both of these respects.

A conserved 5' to 3' exonuclease activity in the yeast and human nucleotide excision repair proteins RAD2 and XPG

Saccharomyces cerevisiae RAD2 protein and its human homolog xeroderma pigmentosum group G (XPG) protein function in the incision step of nucleotide excision repair of DNA damaged by ultraviolet light. Both RAD2 and XPG proteins have been shown previously to possess an endonuclease activity. Using DNA substrates labeled at either the 5' end or 3' end, we now demonstrate that RAD2 protein also digests both single-stranded and double-stranded DNAs exonucleolytically with a 5' to 3' directionality. A 5' to 3' exonuclease activity is also present in the XPG protein, indicating evolutionary conservation of this activity. The possible role of RAD2 and XPG 5' to 3' exonuclease activity in nucleotide excision repair is discussed.

Yeast DNA repair protein RAD5 that promotes instability of simple repetitive sequences is a DNA-dependent ATPase

The RAD5 gene of Saccharomyces cerevisiae functions in postreplication repair of ultraviolet damaged DNA, and interestingly, it also has a role in increasing the instability of simple repetitive sequences in the genome. In contrast to DNA mismatch repair genes which function in maintaining constant length of repeat sequences, RAD5 promotes alterations in the length of repeat sequences. In this work, we purify the RAD5 protein to near homogeneity from yeast cells and show that it is a single-stranded DNA-dependent ATPase. The possible roles of RAD5 ATPase in postreplication gap filling and in increasing the incidence of length alterations of repeat sequences are discussed.

Holliday junction cleavage by yeast Rad1 protein

In Saccharomyces cerevisiae, of the many genes required for excision repair of ultraviolet-damaged DNA, only RAD1 and RAD10 also function in genetic recombination. Complex formation between the RAD1 and RAD10 gene products activates an endonucleolytic function that nicks single-stranded DNA and negatively supercoiled double-stranded DNA. To characterize the recombination role of the proteins Rad1 and Rad10, we have investigated their interaction with the Holliday junction, a four-stranded structure that results from single-stranded crossover between two duplex DNA molecules and whose resolution is obligatory for the generation of mature recombinants. We show that Rad1 binds specifically to a Holliday junction and, in the presence of magnesium, catalyses the endonucleolytic cleavage of the junction. Junction cleavage by Rad1 proceeds sufficiently without Rad10, thus identifying Rad1 as the catalytic subunit of Rad1/Rad10 endonuclease.

Human xeroderma pigmentosum group G gene encodes a DNA endonuclease

Because of defective nucleotide excision repair of ultraviolet damaged DNA, xeroderma pigmentosum (XP) patients suffer from a high incidence of skin cancers. Cell fusion studies have identified seven XP complementation groups, A to G. Previous studies have implicated the products of these seven XP genes in the recognition of ultraviolet-induced DNA damage and in incision of the damage-containing DNA strand. Here, we express the XPG-encoded protein in Sf9 insect cells and purify it to homogeneity. We demonstrate that XPG is a single-strand specific DNA endonuclease, thus identifying the catalytic role of the protein in nucleotide excision repair. We suggest that XPG nuclease acts on the single-stranded region created as a result of the combined action of the XPB helicase and XPD helicase at the DNA damage site.

Intergeneric protoplast fusion between Brassica carinata and Camelina sativa

Camelina sativa is a wild crucifer that is reported to be resistant to Alternaria blight. Polyethylene glycol mediated fusion was attempted between protoplasts from etiolated hypocotyls of Brassica carinata and mesophyll protoplasts of Camelina sativa. The mean frequency of heterokaryons was 6.8%. Three hybrid shoots were regenerated, each from a single fusionderived callus. These shoots failed to produce roots capable of withstanding transplantation. Confirmation of hybridity was obtained from the morphology of in vitro produced leaves, somatic chromosome number in leaf tips, and restriction fragment length polymorphism for a nuclear rDNA probe. Analysis for organelle constitution using RFLPs indicated that the hybrid contained chrloroplasts derived from the wild species and mitochondria from the cultivated Brassica species.

Growth of sitting height, subischial leg length and weight in well-off northwestern Indian children

This paper reports attained means and tempo unconditional 1-year velocities of sitting height, subischial leg length and weight of well-off northwestern Indians based on two time measurements taken by the same measurer. A 3-year difference is observed in reaching the peak sitting height velocity between girls (11 years) and boys (14 years) as in their peak height velocity. While in girls the peak subischial leg length velocity is reached a year earlier, at 10 years, than that of their peak sitting height velocity, in boys it is reached at the same time as in sitting height (14 years). Comparisons of the attained means with the British standards show that while sitting height is shorter throughout in the Indians, the subischial leg length is longer until 12 years in girls and 14 years in boys, after which it becomes equal to that of the British. This differential growth of the two segments comprising stature produces shorter adult height. Though the weight velocities are not dissimilar, the Indian children are lighter throughout. This body shape and size, with relatively longer legs, is a useful adaptation to the northwestern Indian climate.

RAD25 is a DNA helicase required for DNA repair and RNA polymerase II transcription

The RAD25 gene of Saccharomyces cerevisiae functions in nucleotide excision repair of ultraviolet-damaged DNA and is also required for cell viability. The RAD25 protein shows remarkable homology to the protein encoded by the human nucleotide-excision-repair gene XPB (ERCC3), mutations in which cause the cancer-prone disease xeroderma pigmentosum and also Cockayne's syndrome. Here we purify RAD25 protein from S. cerevisiae and show that it contains single-stranded DNA-dependent ATPase and DNA helicase activities. Extract from the conditional lethal mutant rad25-ts24 exhibits a thermolabile transcriptional defect which can be corrected by the addition of RAD25 protein, indicating a direct and essential role of RAD25 in RNA polymerase II transcription. The protein encoded by the rad25799am allele is defective in DNA repair but is proficient in RNA polymerase II transcription, indicating that RAD25 DNA-repair activity is separable from its transcription function. The rad25 Arg-392 encoded product, which contains a mutation in the ATP-binding motif, is defective in RNA polymerase II transcription, suggesting that the RAD25-encoded DNA helicase functions in DNA duplex opening during transcription initiation.

A cross-sectional study of subcutaneous fat in well-off north west Indian children

Attained means and standard deviations of the skinfold thicknesses at triceps, biceps, subscapular and suprailiac sites are presented for 6-16 yr old 589 boys and 566 girls belonging to well-off families residing in Chandigarh, north west India. Girls had larger means throughout the growing period. Limb skinfolds in boys showed a pre-adolescent fatwave followed by a marked decrease in the means. Compared to the British standards, well-off north west Indians had larger triceps and subscapular skinfold thicknesses being closer/above the 75th centile. This agreed well with the observations of earlier workers. Among the possible influencing factors for the fatness of these children, lack of physical activity appeared to be a major one.