The relationship of the delta transfer factor and KColIb to the ColIb plasmid

The structures of the colicin Ib plasmid (ColIb), the delta transfer factor and a plasmid determining kanamycin resistance and colicin Ib production called KColIb, were compared. Radiolabelled mini-ColIb plasmids and isolated DNA fragments of ColIb were used as probes for nitrocellulose blots of digests of the other two large plasmids. The structure of delta was consistent with it having one large deletion of about 10 MDa in the SB fragment and two insertions of approximately 6 MDa and 12 MDa in the SB and SA fragments of the ColIb plasmid. It was hypothesized that KColIb had six small insertions in SA, SB, SE and near the junction of the SB and SD fragments. However, ColIb, KColIb and delta were homologous for at least 70% of their lengths. The highly conserved regions in the three plasmids were the regions that corresponded to fragments SA, SC and SD of ColIb. In addition, delta and KColIb differed from ColIb at similar sites. The possible evolution of these plasmids is discussed.     

Expression of a Lactose Transposon (Tn951) in Zymomonas mobilis

The potential utility of Zymomonas mobilis as an organism for the commercial production of ethanol would be greatly enhanced by the addition of foreign genes which expand its range of fermentable substrates. We tested various plasmids and mobilizing factors for their ability to act as vectors and introduce foreign genes into Z. mobilis CP4. Plasmid pGC91.14, a derivative of RP1, was found to be transferred from Escherichia coli to Z. mobilis at a higher frequency than previously reported for any other plasmids. Both tetracycline resistance and the lactose operon from this plasmid were expressed in Z. mobilis CP4. Plasmid pGC91.14 was stably maintained in Z. mobilis at 30°C but rapidly lost at 37°C.     

Identification and localization of 3-phenylcatechol dioxygenase and 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoate hydrolase genes of Pseudomonas putida and expression in Escherichia coli

The bphC and bphD genes of Pseudomonas putida involved in the catabolism of polychlorinated biphenyls or biphenyl were identified, localized, and studied for expression in Escherichia coli. This was achieved by cloning a 2.4-kilobase (kb) DNA fragment of recombinant cosmid pOH101 into HindIII site of pUC plasmids downstream of a lacZ promoter and measuring the enzyme activities of 3-phenylcatechol dioxygenase (3-PDase; a product of bphC) and the meta-cleavage product 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoate hydrolase (a product of bphD). The amount of 3-PDase produced in E. coli was about 20 times higher than that of the enzyme produced by the parent, P. putida. Determination of expression of the bphC and bphD genes through their own promoter sequences or by using the lacZ promoter of pUC plasmids was done by cloning the DNA that encodes bphC and bphD genes in a HindIII site of a promoter selection vector (pKK232-8) upstream of the gene for chloramphenicol acetyltransferase (CAT). The recombinant plasmid (pAW787) constructed by inserting the 2.4-kb DNA in pKK232-8 expressed both 3-PDase and CAT activities. Another hybrid construct (pAW786) in which the DNA insert was cloned in the opposite orientation lacked CAT activity but produced normal amounts of 3-PDase activity. On the basis of these results, we suggest that the bphC and bphD genes were expressed by using promoter sequences that are independent of the promoter that expresses CAT activity in E. coli. The locations of the bphC and bphD genes were determined by insertional inactivation of the open reading frames of structural genes bphC and bphD by Tn5 mutagenesis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Longitudinal growth of head circumference in Punjabi infants in Chandigarh (India)

One hundred and fifty four (86 male and 68 female) Punjabi infants residing in Chandigarh (India) were longitudinally measured for head circumference at monthly age intervals during first year of life. The general pattern of growth of head circumference was characterised by initial sharp rise followed by slow gain during second half of infancy. Beyond birth male infants, possessed higher and statistically significant mean values than their female counterparts. The pattern-wise similarity between growth curves plotted for Punjabi and Western infants, may be attributed to protective effects of breast feeding. Head circumference velocity showed rapid deceleration immediately after birth up to about 4 months, thereafter, it declined slowly. Sex differences in monthly growth rates were found to be statistically significant (p<0.05) at a few of the age intervals during first year of life.     

Self-transmissible plasmid in Zymomonas mobilis carrying antibiotic resistance.

The cryptic plasmid pRUT41 from Zymomonas mobilis was examined for its biological properties. This plasmid was found to be conjugally transferred from Z. mobilis CP4 to Escherichia coli BM21 and to carry genes for antibiotic resistance (gentamicin, kanamycin, and streptomycin). Covalently closed circular plasmid DNA was isolated from eight transconjugants of E. coli BM21. These plasmids were identical in mobility on agarose gels and exhibited the same restriction patterns as the native pRUT41 plasmid isolated from Z. mobilis. The plasmid location of the antibiotic resistance genes was further confirmed by transforming E. coli BM21 with isolated pRUT41 plasmid from strain CP4 and with plasmids from the transconjugants of BM21. Resistance to streptomycin, kanamycin, and gentamicin was tightly linked and transferred together in all cases.     

Restriction endonuclease mapping of the colicin Ib plasmid

Summary A cleavage site map of the colicin Ib plasmid (ColIb) has been determined for the enzymes Sall, XhoI, and HindIII by analysis of partial digests, double digests, DNA-DNA hybridization, and Tn5-induced insertion mutants. The site of the colicin gene has been determined by probing with cloned DNA coding for colicin production, as well as by analysis of a colicin negative ColIb:Tn5.     

Epigenetic Modulation in Parkinson’s Disease and Potential Treatment Therapies

In the recent past, huge emphasis has been given to the epigenetic alterations of the genes responsible for the cause of neurological disorders. Earlier, the scientists believed somatic changes and modifications in the genetic makeup of DNA to be the main cause of the neurodegenerative diseases. With the increase in understanding of the neural network and associated diseases, it was observed that alterations in the gene expression were not always originated by the change in the genetic sequence. For this reason, extensive research has been conducted to understand the role of epigenetics in the pathophysiology of several neurological disorders including Alzheimer’s disease, Parkinson’s disease and, Huntington’s disease. In a healthy person, the epigenetic modifications play a crucial role in maintaining the homeostasis of a cell by either up-regulating or down-regulating the genes. Therefore, improved understanding of these modifications may provide better insight about the diseases and may serve as potential therapeutic targets for their treatment. The present review describes various epigenetic modifications involved in the pathology of Parkinson’s Disease (PD) backed by multiple researches carried out to study the gene expression regulation related to the epigenetic alterations. Additionally, we will briefly go through the current scenario about the various treatment therapies including small molecules and multiple phytochemicals potent enough to reverse these alterations and the future directions for a better management of PD.