Protein and enzymes regulations towards salt tolerance of some Indian mangroves in relation to adaptation

Elevated substrate salinity and anthropogenic impulse are the major threat to the mangrove ecosystem. In the Indian subcontinent, Sundarbans have the richest mangrove species diversity. Due to geomorphic characteristics and unplanned management, the elevated salinity prevails in the western part and that has direct impact on vegetation. Seven mangrove taxa were examined, of which four (Aegialitis rotundifolia, Heritiera fomes, Xylocarpus granatum, and X. mekongensis) were considered as degrading and three (Bruguiera gymnorrhiza, Excoecaria agallocha, and Phoenix paludosa) were considered as natural control. The targeted taxa were collected from five different islands and were selected on the basis of increasing salinity gradient. As salinity increased from site I to V (11.76–15.2 ppt), the amount of total leaf proteins decreased in all the targeted species and ranged between 5.67 and 25.23%. The percentage of protein depletion was less in Aegialitis, Heritiera, and Xylocarpus than the other three taxa in higher salinity that pointed out their less adaptability, as degradation of protein may be essential for efficient stress management. Two antioxidative (peroxidase and superoxide dismutase) and two hydrolyzing (acid phosphatase and esterase) enzymes showed a positive correlation with salinity. In four degrading taxa, the percentage of enzyme increment was less than those of their natural control taxa. Salinity imposed increment of antioxidant enzymes facilitate ROS scavenging, which is an inevitable elevated byproduct during photo-inhibition. Lower amount and number of isoforms in higher salinity indicated towards less suitability of Aegialitis rotundifolia, Heritiera fomes, Xylocarpus granatum, and X. mekongensis in increased salinity level of western Sundarbans.     

Developmental changes in the distribution of rat brain pyroglutamate aminopeptidase,a possible determinant of endogenous cyclo(His-Pro) concentrations

The distribution of cyclo(His-Pro), thyrotropin-releasing hormone (TRH) and Pyroglutamate aminopeptidase activity in adult and developing rat brains were studied. A comparison of the subcellular distribution of Pyroglutamate aminopeptidase activity in hypothalamic and cerebral cortical extracts from adult rats exhibited remarkable differences. In hypothalamus, the enzyme activity was mainly associated with the soluble fraction whereas in cortex it was predominantly associated with the particulate fractions. During postnatal development, the brain concentrations of cyclo(His-Pro) and Pyroglutamate aminopeptidase activities declined with age. These data suggest that Pyroglutamate aminopeptidase activity, but not TRH, plays an active role in determining the levels of endogenous cyclo(His-Pro) concentrations in brain.     

Distribution and characterization of cyclo (His-Pro)-like immunoreactivity in anuran (frog) skins

The distribution of cyclo (His-Pro)-like immunoreactivity in frog skins from seven frog species was examined. The chromatographic elution profile of cyclo (His-Pro)-like immunoreactivity in amphibian skins measured by radioimmunoassay corresponded precisely to that of [³H-Pro]-cyclo (His-Pro) after DEAE-Cellulose, Sephadex G-25 and high-pressure liquid chromatography. The concentrations of cyclo (His-Pro) in frog skins were much higher than the concentrations of TRH previously observed in skin and the concentrations of cyclo (His-Pro) in both brain and gastrointestinal tract.     

Tryptophan catabolism during sporulation in Bacillus cereus

1. Two intermediates of tryptophan catabolism were isolated from a sporulating culture of Bacillus cereus and identified as anthranilic acid and kynurenine by their spectral properties. 2. During sporulation the rate of formation of anthranilic acid and kynurenine by whole cells increased and reached a maximum at the pre-spore stage. 3. The specific activities of tryptophan pyrrolase and formylase also increased during sporulation and exhibited a maximal activity at the pre-spore stage. 4. Kynureninase activity reached a maximum during early stages of sporulation and then started to decline. 5. There was a net increase in the activity of tryptophan pyrrolase when cells were grown in the presence of l-tryptophan or dl-kynurenine. 6. The cultures exhibited the maximal activity of kynureninase 2h earlier in the presence of dl-kynurenine whereas l-tryptophan delayed the appearance of the maximal activity by 2h. 7. The omission of glucose from the medium had no effect on the pattern of development of tryptophan pyrrolase during growth and sporulation. 8. On the addition of tryptophan to a chemically defined medium no significant change in the pattern of development of tryptophan pyrrolase was observed.     

Is all cyclo(His-Pro) derived from thyrotropin-releasing hormone?

Cyclo(His-Pro), or histidyl-proline diketopiperazine, is an endogenous cyclic dipeptide that is ubiquitously distributed in tissues and body fluids of both man and animals. This cyclic dipeptide is not only structurally related to thyrotropin-releasing hormone (TRH, pGlu-His-ProNH₂), but it can also arise from TRH by the action of the enzyme pyroglutamate amino-peptidase (pGlu-peptidase). The data on the distribution of TRH, cyclo(His-Pro), and pGlu-peptidase under normal and abnormal conditions are summarized and potential relationships analyzed. We conclude that all of the cyclo(His-Pro) cannot be derived from TRH. Two additional sources of cyclo(His-Pro) are suggested. It is proposed that 29,247 molecular weight TRH prohormone, prepro TRH, which contains 5 copies of TRH sequence, can be processed to yield cyclo(His-Pro). Thus, both TRH and cyclo(His-Pro) share a common precursor, prepro[TRH/Cyclo(His-Pro)].     

Linearization of excitatory synaptic integration at no extra cost

In many theories of neural computation, linearly summed synaptic activation is a pervasive assumption for the computations performed by individual neurons. Indeed, for certain nominally optimal models, linear summation is required. However, the biophysical mechanisms needed to produce linear summation may add to the energy-cost of neural processing. Thus, the benefits provided by linear summation may be outweighed by the energy-costs. Using voltage-gated conductances in a relatively simple neuron model, this paper quantifies the cost of linearizing dendritically localized synaptic activation. Different combinations of voltage-gated conductances were examined, and many are found to produce linearization; here, four of these models are presented. Comparing the energy-costs to a purely passive model, reveals minimal or even no additional costs in some cases.     

Understanding ageing effects using complexity analysis of foot–ground clearance during walking

Ageing influences gait patterns which in turn can affect the balance control of human locomotion. Entropy-based regularity and complexity measures have been highly effective in analysing a broad range of physiological signals. Minimum toe clearance (MTC) is an event during the swing phase of the gait cycle and is highly sensitive to the spatial balance control properties of the locomotor system. The aim of this research was to investigate the regularity and complexity of the MTC time series due to healthy ageing and locomotors' disorders. MTC data from 30 healthy young (HY), 27 healthy elderly (HE) and 10 falls risk (FR) elderly subjects with balance problems were analysed. Continuous MTC data were collected and using the first 500 data points, MTC mean, standard deviation (SD) and entropy-based complexity analysis were performed using sample entropy (SampEn) for different window lengths (m) and filtering levels (r). The MTC SampEn values were lower in the FR group compared to the HY and HE groups for all m and r. The HY group had a greater mean SampEn value than both HE and FR reflecting higher complexity in their MTC series. The mean SampEn values of HY and FR groups were found significantly different for m = 2, 4, 5 and r = (0.1–0.9) × SD, (0.3–0.9) × SD and (0.3–0.9) × SD, respectively. They were also significant difference between HE and FR groups for m = 4–5 and r = (0.3–0.7) × SD, but no significant differences were seen between HY and HE groups for any m and r. A significant correlation of SampEn with SD of MTC was revealed for the HY and HE groups only, suggesting that locomotor disorders could significantly change the regularity or the complexity of the MTC series while healthy ageing does not. These results can be usefully applied to the early diagnosis of common gait pathologies.     

Standardization and validation of a simple,sensitive, second antibody format enzyme immunoassay for growth hormone determination in mithun (Bos frontalis) plasma

To facilitate research into the action of growth hormone (GH) in mithun (Bos frontalis), we standardized and validated a simple and highly sensitive enzyme immunoassay (EIA) for GH determination in mithun blood plasma on microtiter plates using biotin‐streptavidin amplification system and the second antibody coating technique. Biotin was coupled to GH and used to bridge between streptavidin‐peroxidase and immobilized antiserum in competitive assay. The EIA was carried out directly in 25 µl mithun plasma. The GH standards ranging from 0.25 ng/well/25 µl to 128 ng/well/25 µl were prepared in charcoal‐treated plasma collected from an aged (>10 years) senile mithun. The sensitivity of EIA procedure was 1.0 ng/ml plasma; the 50% relative binding sensitivity was seen at 36 ng/ml plasma. Plasma volumes for the EIA, namely 12.5 and 25 µl, did not influence the shape of standard curve even though a drop in the optical density (OD)₄₅₀ observed with higher plasma volumes was due to higher inherent GH content in mithun plasma collected from an aged (>10 years) senile mithun. For the biological validation of assay, two mithuns were administered with synthetic bovine GH‐releasing factor (GRF; 10 µg/100 kg body weight; intravenous) and another two were administered sterile normal saline (controls). Jugular blood samples were collected at ?60, ?45, ?30, ?15, ?10, ?5, 0, 5, 10, 15, 30 min and thereafter at 15‐min intervals beginning 1 hour before GRF injection up to 8‐hr post treatment, and samples were assayed for plasma GH. In two animals, a peak of GH was recorded at 15 min of GRF administration, which confirms the biological validation of the EIA. Plasma GH estimated in blood samples collected for 6 consecutive weeks from two different age groups of mithun (Group I, age 0–3 months; Group II, age 3–4 yr) showed higher (P < 0.0001) mean plasma GH in younger than in adult mithuns and consequently higher growth rates in the younger group. A parallelism test conducted between a buffer standard curve of bovine GH and GH measured from serial dilution of mithun plasma containing high concentration of endogenous GH showed good parallelism with a standard curve. In conclusion, the EIA developed for GH determination in mithun blood plasma is sufficiently reliable, economic, and sensitive enough to estimate mithun GH in all physiologic variations. Zoo Biol 0:1–11, 2005. © 2005 Wiley‐Liss, Inc.     

Comparative Chemical Composition and Acetylcholinesterase (AChE) Inhibitory Potential of Cinnamomum camphora and Cinnamomum tamala

Cinnamomum species have applications in the pharmaceutical and fragrance industry for wide biological and pharmaceutical activities. The present study investigates the chemical composition of the essential oils extracted from two species of Cinnamomum namely C. tamala and C. camphora. Chemical analysis showed E-cinnamyl acetate (56.14 %), E-cinnamaldehyde (20.15 %), and linalool (11.77 %) contributed as the major compounds of the 95.22 % of C. tamala leaves essential oil found rich in phenylpropanoids (76.96 %). C. camphora essential oil accounting for 93.57 % of the total oil composition was rich in 1,8-cineole (55.84 %), sabinene (14.37 %), and α-terpineol (10.49 %) making the oil abundant in oxygenated monoterpenes (70.63 %). Furthermore, the acetylcholinesterase inhibitory activity for both the essential oils was carried out using Ellman's colorimetric method. The acetylcholinesterase inhibitory potential at highest studied concentration of 1 mg/mL was observed to be 46.12±1.52 % for C. tamala and 53.61±2.66 % for C. camphora compared to the standard drug physostigmine (97.53±0.63 %) at 100 ng/ml. These multiple natural aromatic and fragrant characteristics with distinct chemical compositions offered by Cinnamon species provide varied benefits in the development of formulations that could be advantageous for the flavor and fragrance industry.