Detection and Characterization of Pediocin PA-1/AcH like Bacteriocin Producing Lactic Acid Bacteria

Fifty-five bacteriocinogenic lactic acid bacteria (LAB) isolated from seven different sources. Eight isolates were found to produce pediocin PA-1 like bacteriocin as detected by pedB gene PCR and dot-blot hybridization. The culture filtrate (CF) activity of these isolates exhibited strong antilisterial, antibacterial activity against tested food-borne pathogens and LAB. The identification and genetic diversity among the selected LAB was performed by conventional morphological and molecular tools like RFLP, RAPD, and 16S rDNA gene sequencing. The isolates were identified as, 1 each of Pediococcus acidilactici Cb1, Lactobacillus plantarum Acr2, and Streptococcus equinus AC1, 2 were of P. pentosaceus Cb4 and R38, and other 3 were Enterococcus faecium Acr4, BL1, V3. Partial characterization of the bacteriocins revealed that the peptide was heat-stable, active at acidic to alkaline pH, inactivated by proteolytic enzymes, and had molecular weight around 4.6 kDa and shared the properties of class IIa pediocin-family. The bacteriocin production at different temperatures, pH, and salt concentrations was studied to investigate the optimal condition for application of these isolates as a starter culture or as a biopreservative in either acidic or non-acidic foods.     

Culture and regeneration of mesophyll-derived protoplasts of sorghum [Sorghum bicolor (L.) Moench]

 A protocol for plant regeneration from mesophyll/protoplasts of sorghum [Sorghum bicolor (L.) Moench] was developed. The yield of intact protoplasts, their subsequent divisions and regeneration were genotype-dependent. The genotype 296B was always more responsive than IS 32266. For 296B, the sixth leaf from 18-day-old plants kept in dark for 2 days before harvesting was found to be the most suitable source of viable protoplasts. The first division was observed 10–12 days after plating, and the second division after 12–14 days. The maximum plating efficiency was 4.8% in 296 B, followed by 2.48% in IS 32266. Microcolonies were visible after 25–30 days, and microcalli after 60–75 days. Whole plants were obtained after 6–8 weeks of culture of microcalli on MS medium containing 0.2 mg l^–1 kinetin and 2 mg l^–1 BAP. The frequency of regeneration in 296B and IS 32266 was 12.80% and 10.58%, respectively. Ten plants transferred to pots in the glasshouse established well. The seeds collected from glasshouse-grown plants were sown in the field where plants were grown to maturity. Received: 7 October 1998 / Revision received: 13 January 1999 / Accepted: 20 January 1999     

Swim exercise training and adaptations in the antioxidant defense system of myocardium of old rats: relationship to swim intensity and duration

We examined a suitable swim program of different intensities and durations that could evoke changes in the myocardial antioxidant capacity in 22-month-old rats. Male rats (Rattus norvegicus) were assigned to either a sedentary control (SE-C) group or one of six trainee groups. Animals were swim-exercised for 4 weeks with either 20 min or 40 min/day, and three intensities, low, moderate and high. Low-intensity at 20 min/day elicited maximum swim velocity (Sv) and endurance capacity (P<0.05). While serum total cholesterol, triglyceride and low-density lipoprotein (LDL-C) levels were significantly reduced, high-density lipoprotein (HDL-C) showed an increase (P<0.05) in low-intensity trained rats (20 min/day) over SE-C. Notable reduction in blood lactate was also evident. Exercise training significantly increased superoxide dismutase (Mn-SOD), decreased lipid peroxidation products, malondialdehyde and lipofuscin in the left and right ventricles. Increased Mn-SOD with concomitant decrease in lipofuscin in left ventricle was significantly greater than in right ventricle. Moderate- to high-intensity exercise was not effective in either reducing lipid peroxidation products or elevating Mn-SOD activity. These data suggest that swim training at low-intensity of 20 min/day is beneficial as a major protective adaptation against oxidative stress in old myocardium.     

Influence of DNA structures on the conversion of sanguinarine alkanolamine form to iminium form

Sanguinarine exhibits pH dependent structural equilibrium between iminium form (structure I) and alkanolamine form (structure II) with a pKa of 7.4 as revealed from spectrophotometric titration. The titration data show that the compound exists almost exclusively as structure I and structure II in the pH range 1 to 6 and 8.5 to 11, respectively. The interaction of structure I and structure II to several B-form natural and synthetic double and single stranded DNAs has been studied by spectrophotometric, spectrofluorimetric and circular dichroic measurements in buffers of pH 5.2 and pH 10.4 where the physicochemical properties of DNA remain in B-form structure. The results show that structure I bind strongly to all B-form DNA structures showing typical hypochromism and bathochromism of the alkaloid's absorption maximum, quenching of steady-state fluorescence intensity and perturbations in circular dichroic spectrum. The structure II does not bind to DNA, but in presence of large amount of DNA significant population of structure I is generated, which binds to DNA and forms a structure I-DNA intercalated complex. The nature and magnitude of the spectral pattern are very much dependent on the structure as well as base composition of each DNA. The generation of the structure I from structure II is significantly affected by increasing ionic strength of the medium. The conversion of structure II to structure I in presence of high concentration of DNA in solution is explained through formation of a binding equilibrium process between structure II and structure I-DNA intercalated complex.     

Effect of fish oil on mitochondrial respiration in isoproterenol induced myocardial infarction in rats

Following isoproterenol treatment mitochondrial lipid peroxidation, phosphoslipase activity, lactate and calcium increased significantly, while activities of tricarboxylic acid cycle enzymes, enzymes of respiratory chain and ATP production showed decline. Oxidative phosphorylation was also affected on isoproterenol treatment with significant reduction in all the variables. Fish oil pretreatment in isoproterenol treated rats showed improved mitochondrial energy metabolism. The results suggest cardioprotective effect of fish oil.     

Stable free radical scavenging and antiperoxidative properties of resveratrol compared in vitro with some other bioflavonoids

Stable free radical scavenging and antiperoxidative activities of resveratrol, a component of grapes and red wine, were evaluated and compared with some other known bioflavonoids (quercetin, catechin, kaempferol, myricetin, fisetin, ellagic acid and naringenin) widely present in the plant kingdom. Free radical scavenging activity was measured in an in vitro chemical system (DPPH assay), while for antiperoxidative activity, biological system comprising of hepatic and pulmonary homogenates was employed. Antiradical activity assay showed quercetin and myricetin to be stronger antiradical agents than resveratrol. Structure-activity study revealed that O-dihydroxy group on ring B of flavonoid plays a crucial role. A double bond at 2-3 position conjugated with a 4-oxo function and hydroxy groups at positions 3 and 5 also contribute towards antiradical activity of flavonoids. Resveratrol exhibited stronger antiradical activity than kaempferol and naringenin and was also more efficient than alpha-tocopherol, a known strong endogenous non-flavonoid antioxidant, used for comparison. In vitro antiperoxidative assay showed fisetin as the strongest and kaempferol as the weakest antioxidant. Resveratrol was found to be stronger antioxidant than catechin, myricetin, kaempferol and naringenin, but was weaker than quercetin, fisetin and alpha-tocopherol. Antiradical and antiperoxidative activities of resveratrol may explain its beneficial effects in disease states. Assays exhibited no direct correlation between antiradical and antiperoxidative activities of the phenolics.     

Effect of abana an ayurvedic formulation,on lipid peroxidation in experimental myocardial infarction in rats

The present study was conducted to elucidate the antioxidant role of an ayurvedic formulation Abana in isoproterenol induced myocardial infarction in rats. In myocardial necrosis induced by isoproterenol, a significant increase in serum iron content with a significant decrease in plasma iron binding capacity, ceruloplasmin activity and glutathione level were observed. There was also a significant increase in lipid peroxides levels on isoproterenol administration. Activities of antioxidant enzymes like superoxide dismutase, catalase, glutathione peroxidase, glutathione-s-transferase, glutathione reductase were decreased significantly in heart with isoproterenol-induced myocardial necrosis. Abana, produced a marked reversal of these metabolic changes related to myocardial infarction induced by isoproterenol. In conclusion ayurvedic formulation Abana exerts its effect by modulating lipid peroxidation and enhancing antioxidant and detoxifying enzyme systems.     

Alterations of the Characteristics of the Circadian Rest‐Activity Rhythm of Cancer In‐Patients

The aim of the present study was to evaluate the characteristics of the circadian rest‐activity rhythm of cancer patients. Thirty‐one in‐patients, consisting of 19 males and 12 females, were randomly selected from the Regional Cancer Center, Pandit Jawaharlal Nehru Medical College, Raipur, India. The rest‐activity rhythm was studied non‐invasively by wrist actigraphy, and compared with 35 age‐matched apparently healthy subjects (22 males and 13 females). All subjects wore an Actiwatch (AW64, Mini Mitter Co. Inc., USA) for at least 4–7 consecutive days. Fifteen‐second epoch length was selected for gathering actigraphy data. In addition, several sleep parameters, such as time in bed, assumed sleep, actual sleep time, actual wake time, sleep efficiency, sleep latency, sleep bouts, wake bouts, and fragmentation index, were also recorded. Data were analyzed using several statistical techniques, such as cosinor rhythmometry, spectral analysis, ANOVA, Duncan's multiple‐range test, and t‐test. Dichotomy index (I<O) and autocorrelation coefficient (r24) were also computed. The results validated a statistically significant circadian rhythm in rest‐activity with a prominent period of 24 h for most cancer patients and control subjects. Results of this study further revealed that cancer patients do experience a drastic alteration in the circadian rest‐activity rhythm parameters. Both the dichotomy index and r24 declined in the group of cancer patients. The occurrence of the peak (acrophase, Ø) of the rest‐activity rhythm was earlier (p<0.001) in cancer patients than age‐ and gender‐matched control subjects. Results of sleep parameters revealed that cancer patients spent longer time in bed, had longer assumed and actual sleep durations, and a greater number of sleep and wake bouts compared to control subjects. Further, nap frequency, total nap duration, average nap, and total nap duration per 1 h awake span were statistically significantly higher in cancer patients than control subjects. In conclusion, the results of the present study document the disruption of the circadian rhythm in rest‐activity of cancer in‐patients, with a dampening of amplitude, lowering of mean level of activity, and phase advancement. These alterations of the circadian rhythm characteristics could be attributed to disease, irrespective of variability due to gender, sites of cancer, and timings of therapies. These results might help in designing patient‐specific chronotherapeutic protocols.     

The Small GTPase RhoA Is Required for Proper Locomotor Circuit Assembly

The assembly of neuronal circuits during development requires the precise navigation of axons, which is controlled by attractive and repulsive guidance cues. In the developing spinal cord, ephrinB3 functions as a short-range repulsive cue that prevents EphA4 receptor-expressing corticospinal tract and spinal interneuron axons from crossing the midline, ensuring proper formation of locomotor circuits. Here we report that the small GTPase RhoA, a key regulator of cytoskeletal dynamics, is also required for ephrinB3/EphA4-dependent locomotor circuit formation. Deletion of RhoA from neural progenitor cells results in mice that exhibit a rabbit-like hopping gait, which phenocopies mice lacking ephrinB3 or EphA4. Consistent with this locomotor defect, we found that corticospinal tract axons and spinal interneuron projections from RhoA-deficient mice aberrantly cross the spinal cord midline. Furthermore, we determined that loss of RhoA blocks ephrinB3-induced growth cone collapse of cortical axons and disrupts ephrinB3 expression at the spinal cord midline. Collectively, our results demonstrate that RhoA is essential for the ephrinB3/EphA4-dependent assembly of cortical and spinal motor circuits that control normal locomotor behavior.     

Molecular characterization of reciprocal crosses of Aerides vandarum and Vanda stangeana (Orchidaceae) at the protocorm stage

Aerides vandarum and Vanda stangeana are two rare and endangered vandaceous orchids with immense floricultural traits. The intergeneric hybrids were synthesized by performing reciprocal crosses between them. In vitro germination response of the immature hybrid embryos was found to be best on half-strength Murashige and Skoog medium supplemented with 20% (v/v) coconut water/liquid endosperm from tender coconut. Determination of hybridity was made as early as the immature seeds or embryos germinated in vitro, using randomly amplified polymorphic DNA (RAPD) markers. Out of 15 arbitrarily chosen decamer RAPD primers, two were found to be useful in amplification of polymorphic bands specific to the parental species and their presence in the reciprocal crosses. However, a decisive profile that can identify the reciprocal crosses could not be provided by RAPD. Amplification of the trnL-F non-coding regions of chloroplast DNA of the parent species and hybrids aided easy identification of the reciprocal crosses from the fact that maternal inheritance of chloroplast DNA held true for these intergeneric hybrids. Subsequent restriction digestion of the polymerase chain reaction (PCR) amplified trnL-F non-coding regions of chloroplast DNA also consolidated the finding. Such PCR-based molecular markers could be used for early determination of hybridity and easy identification of the reciprocal crosses.