Effect of Single Low Intensity Light Pulse Exposure and Melatonin Treatment on the Circadian Variation of Melatonin in Indian Palm Squirrel Funambulus pennanti

The endogenous circadian rhythm of melatonin in mammals provides information regarding the resetting response of the mammalian circadian timing system in response to the changes in light dark cycle. Photoperiodic changes are reported to have acute and chronic effect on melatonin rhythm. Our aim in present experiment was to study the effect of single light pulse of low intensity on the circadian variation of melatonin in Indian palm squirrel. A short pulse of 5min was given to the animals at 22:55 h on day 16th in natural photoperiodic condition of long day length (LD ~ 13.55:10.05) and melatonin levels were estimated at every 4-h interval on ZT scale on day 17th (DD). Observations suggest that the light pulse given on day 16th suppressed the melatonin level on day 17th (DD). Besides this, it was also found that there was phase delay in the peak value of melatonin. Further, we tested the ability of single melatonin injection on the light pulse induced phase shift of acrophase of melatonin in this species F. pennanti. We injected the single physiological dose of melatonin (25 microgram/100 g body wt.) just 5 min prior to the commencement of light pulse (22:50 h) on day 16 and melatonin levels were estimated on day 17th as above. Injection of melatonin prior to light pulse altered the suppressing and phase shifting effect of light in terms of peak concentration of melatonin in squirrels. Above data may lead us to conclude that the biological clock mechanism controlling circadian rhythm of melatonin in this rodent is in response to the phase shifting effect of light and acute melatonin treatment. Further, we may suggest that single melatonin injection has the capability to entrain melatonin rhythm but a dose dependent study is required to facilitate the suggestion.     

Ectopic expression of Atleafy in Brassica juncea cv. Geeta for early flowering

High temperature stress during pod filling severely affects the yield of Brassica juncea. Early flowering can evade the terminal heat stress and result in early maturity of the crop. In this study, a regeneration and transformation protocol has been standardized for B. juncea cv. Geeta. Hypocotyl from 5-day-old seedlings were used as explants. Of the various combinations of auxins and cytokinins tried along with Murashige and Skoog’s (Physiol Plant 15:473–497, 1962) medium, MS + IAA (0.2 mg/l) + BA (3 mg/l) proved best for shoot regeneration with 89.9 % regeneration efficiency. To induce early flowering Leafy gene from Arabidopsis thaliana was transformed using Agrobacterium mediated transformation method. After 12 weeks transgenic plants showed flowering in vitro whereas their untransformed counterpart did not flower even after 16 weeks. The maximum transformation frequency was 4 %.     

Medaka fish exhibits longevity gender gap,a natural drop in estrogen and telomere shortening during aging: a unique model for studying sex-dependent longevity

Introduction

Females having a longer telomere and lifespan than males have been documented in many animals. Such linkage however has never been reported in fish. Progressive shortening of telomere length is an important aging mechanism. Mounting in vitro evidence has shown that telomere shortening beyond a critical length triggered replicative senescence or cell death. Estrogen has been postulated as a key factor contributing to maintenance of telomere and sex-dependent longevity in animals. This postulation remains unproven due to the lack of a suitable animal system for testing. Here, we introduce a teleost model, the Japanese medaka Oryzias latipes, which shows promise for research into the molecular mechanism(s) controlling sex difference in aging.

Results

Using the medaka, we demonstrate for the first time in teleost that (i) sex differences (female?>?male) in telomere length and longevity also exist in fish, and (ii) a natural, ‘menopause’-like decline of plasma estrogen was evident in females during aging. Estrogen levels significantly correlated with telomerase activity as well as telomere length in female organs (not in males), suggesting estrogen could modulate telomere length via telomerase activation in a sex -specific manner. A hypothetical in vivo ‘critical’ terminal restriction fragment (TRF, representing telomere) length of approximately 4 kb was deduced in medaka liver for prediction of organismal mortality, which is highly comparable with that for human cells. An age conversion model was also established to enable age translation between medaka (in months) and human (in years). These novel tools are useful for future research on comparative biology of aging using medaka.

Conclusion

The striking similarity in estrogen profile between aging female O. latipes and women enables studying the influence of “postmenopausal” decline of estrogen on telomere and longevity without the need of invasive ovariectomy. Medaka fish is advantageous for studying the direct effect of increased estrogen on telomere length and longevity without the breast cancer complications reported in rodents. The findings strongly support the notion that O. latipes is a unique non-mammalian model for validation of estrogenic influence on telomere and longevity in vertebrates. This laboratory model fish is of potential significance for deciphering the ostensibly conserved mechanism(s) of sex-associated longevity in vertebrates.

     

Age-Related Behavioral Phenotype of an Astrocytic Monoamine Oxidase-B Transgenic Mouse Model of Parkinson’s Disease

We have previously shown that increases in astrocytic monoamine oxidase-B (MAO-B) expression, mimicking that which occurs with aging and in neurodegenerative disease, in a doxycycline (dox)-inducible transgenic mouse model evokes neuropathological similarities to what is observed in the human parkinsonian brain. Additional behavioral and neuropathological studies could provide further validation for its usage as a model for Parkinson’s disease (PD). In the present study, we utilized a battery of behavioral tests to evaluate age-related phenotype in this model. In the open field test, we found that dox-induction impaired motor ability with decreases in movement and ambulatory function as well as diminished stereotypical, repetitive movement episodes in both young and old mice. Older mice also showed decreased motor performance in the pole test when compared to younger mice. Furthermore, dox-induced older mice displayed severe hindlimb clasping and the most significant loss of dopamine (DA) in the striatum when compared to young and non-induced animals. Additionally, increased MAO-B activity significantly correlated with decreased expression of striatal DA. The results of our study further confirms that the dox-inducible astrocytic MAO-B transgenic mouse displays similar age-related behavioral and neuropathological features to other models of PD, and could serve as a useful tool to study PD pathophysiology and for the evaluation of therapeutic interventions.     

Detailed Molecular Epidemiologic Characterization of HIV-1 Infection in Bulgaria Reveals Broad Diversity and Evolving Phylodynamics

Limited information is available to describe the molecular epidemiology of HIV-1 in Bulgaria. To better understand the genetic diversity and the epidemiologic dynamics of HIV-1 we analyzed 125 new polymerase (pol) sequences from Bulgarians diagnosed through 2009 and 77 pol sequences available from our previous study from persons infected prior to 2007. Epidemiologic and demographic information was obtained from each participant and phylogenetic analysis was used to infer HIV-1 evolutionary histories. 120 (59.5%) persons were infected with one of five different HIV-1 subtypes (A1, B, C, F1 and H) and 63 (31.2%) persons were infected with one of six different circulating recombinant forms (CRFs; 01_AE, 02_AG, 04_cpx, 05_DF, 14_BG, and 36_cpx). We also for the first time identified infection with two different clusters of unique A-like and F-like sub-subtype variants in 12 persons (5.9%) and seven unique recombinant forms (3.5%), including a novel J/C recombinant. While subtype B was the major genotype identified and was more prevalent in MSM and increased between 2000–2005, most non-B subtypes were present in persons ≥45 years old. CRF01_AE was the most common non-B subtype and was higher in women and IDUs relative to other risk groups combined. Our results show that HIV-1 infection in Bulgaria reflects the shifting distribution of genotypes coincident with the changing epidemiology of the HIV-1 epidemic among different risk groups. Our data support increased public health interventions targeting IDUs and MSM. Furthermore, the substantial and increasing HIV-1 genetic heterogeneity, combined with fluctuating infection dynamics, highlights the importance of sustained and expanded surveillance to prevent and control HIV-1 infection in Bulgaria.     

Calmodulin-dependent cyclic nucleotide phosphodiesterase (PDE1) splice variants from bovine cardiac muscle

Calmodulin-dependent cyclic nucleotide phopshodiesterase (PDE1) has been extensively characterized and is a key enzyme involved in the complex interaction between cyclic nucleotide and Ca(2+) second-messenger systems. It is well established that PDE1 exists in different isozymes. For example, bovine brain tissue has two PDE1 isozymes (PDE1A2 and PDE1B1) whereas only one form (PDE1A1) is reported in bovine cardiac tissue. In this study, we report the cloning of two cDNA splice variants of PDE1: PDE1-small and PDE1-large, from bovine cardiac tissue. Their amino acid sequence similarity to PDE1 sequences from other mammalian species showed that all are very conserved, suggesting their importance in cellular functions. Interestingly, compared to other mammalian species, bovine PDE1A, PDE-small and PDE-large show a deletion at the C-terminal end of the catalytic domain of the gene. Although the significance of this deletion at this crucial location of the gene is not known, we have successfully over-expressed both PDE1-small and PDE1-large splice variants in E. coli and these splice variants are characterized in terms of Western blot, biotinylated calmodulin overlay and peptide mass fingerprinting. Results from these studies suggested that these two splice variants belong to the PDE1 superfamily. To our knowledge, this is the first report on cloning and characterization of these cDNA variants from bovine cardiac tissue. Since there are at least two isoforms of PDE1 in bovine heart tissue, this merits further in-depth study.     

HET0016, a Selective Inhibitor of 20-HETE Synthesis,Decreases Pro-Angiogenic Factors and Inhibits Growth of Triple Negative Breast Cancer in Mice

A selective inhibitor of 20-HETE synthesis, HET0016, has been reported to inhibit angiogenesis. 20-HETE has been known as a second mitogenic messenger of angiogenesis inducing growth factors. HET0016 effects were analyzed on MDA-MB-231 derived breast cancer in mouse and in vitro cell line. MDA-MB-231 tumor cells were implanted in animals’ right flank and randomly assigned to early (1 and 2), starting treatments on day 0, or delayed groups (3 and 4) on day 8 after implantation of tumor. Animals received HET0016 (10 mg/kg) treatment via intraperitoneal injection for 5 days/week for either 3 or 4 weeks. Control group received vehicle treatment. Tumor sizes were measured on days 7, 14, 21, and 28 and the animals were euthanized on day 22 and 29. Proteins were extracted from the whole tumor and from cells treated with 10 µM HET0016 for 4 and 24 hrs. Protein array kits of 20 different cytokines/factors were used. ELISA was performed to observe the HIF-1α and MMP-2 protein expression. Other markers were confirmed by IHC. HET0016 significantly inhibited tumor growth in all treatment groups at all-time points compared to control (p<0.05). Tumor growth was completely inhibited on three of ten animals on early treatment group. Treatment groups showed significantly lower expression of pro-angiogenic factors compared to control at 21 days; however, there was no significant difference in HIF-1α expression after treatments. Similar results were found in vitro at 24 hrs of HET0016 treatment. After 28 days, significant increase of angiogenin, angiopoietin-1/2, EGF-R and IGF-1 pro-angiogenic factors were found (p<0.05) compared to control, as well as an higher intensity of all factors were found when compared to that of 21 day’s data, suggesting a treatment resistance. HET0016 inhibited tumor growth by reducing expression of different set of pro-angiogenic factors; however, a resistance to treatment seemed to happen after 21 days.     

The Quantitative Imaging Network: NCI's Historical Perspective and Planned Goals

The purpose of this editorial is to provide a brief history of National Institutes of Health National Cancer Institute (NCI) workshops as related to quantitative imaging within the oncology setting. The editorial will then focus on the recently supported NCI initiatives, including the Quantitative Imaging Network (QIN) initiative and its organizational structure, including planned research goals and deliverables. The publications in this issue of Translational Oncology come from many of the current members of this QIN research network.