Desynchronization of oral temperature, pulse and performance circadian rhythms in shift working Indian nurses.

Circadian time structure in shift working Indian nurses was studied. In shift workers desynchronization between circadian rhythms in different physiological variables was observed. Circadian amplitudes of oral temperature, pulse and random add speed rhythms decreased significantly in shift workers as compared to control subjects. Circadian mesors of performance rhythms increased significantly in shift workers indicating that the time taken by them was more for performing the tasks. It can be concluded that the subjects studied herein are intolerant to shift work and amplitude decrement may be considered as a chronobiologic index to determine the tolerance of individual workers to shift work.     

Towards domestication of giant kelp (<Emphasis Type="Italic">Macrocystis pyrifera</Emphasis>) in Chile: selection of haploid parent genotypes,outbreeding, and heterosis

Macrocystis is an important marine resource in Chile, with severe problems of over-exploitation. Our study describes genetic materials and techniques for a further improvement of laboratory-based mariculture. For a systematic hybridization program we have selected one pair (cultivar) of gametophytes with favorable somatic and reproductive characteristics from each of seven localities in southern Chile. Sporophytes from all 49 crosses were grown for 10 weeks to seedling size. We report here that sporophytes from sympatric parents (intra-cultivar matings) grow to different length, depending on the locality and, importantly, that sporophytes from several inter-cultivar crossings show superior growth, suggesting heterosis with symmetric or asymmetric reciprocity. The genetic materials and techniques described here, together with our newly developed standardized seedling production protocols now available, constitute a significant step towards domestication of Macrocystis in analogy to terrestrial agriculture.     

Isozymes of <Emphasis Type="Italic">α</Emphasis>-amylases from newly isolated <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> CKB19: Production from immobilized cells

The aim of this study was to produce two isozymes of α-amylase by immobilization of a newly isolated soil bacterium. The bacterium was identified as Bacillus thuringiensis CKB19 on the basis of its 16S rRNA profile. Enzyme production by free cells increased linearly with cell growth up to 34 h in starch containing enriched liquid media. The active bacterial cells were immobilized in Caalginate beads, and operational stability of the entrapped cell was optimized for amylase production. Enzyme production was optimal at an alginate concentration of 2 g% (w/v), calcium chloride concentration of 1 M, and with 300 beads (each bead contained 2 × 10⁷ cells)/250 mL flask. Amylase production by the immobilized cells was about 3 times higher than free cell fermentation after 34 h of incubation. It was observed that the immobilized bacterium secreted two different amylases (Am-I and Am-II) into the culture fluid. The molecular masses of Am-I and Am-II were 59.6 and 44.7 kd, respectively, and showed optimum activity at pH 5.0 and 9.0. Both amylases showed optimum activity at 40°C and were stable at the same temperature, with losses of only 10 and 20% (for Am I and Am II, respectively) of their original activities after 24 h of incubation. Further, both amylases were salt tolerant (up to 4 M NaCl) and hydrolyzed raw starchy foods into glucose. All these characteristics make this enzyme mixture suitable for use as a digestive aid and for the improvement of digestibility of animal feed ingredients.     

Mass spectrometry applied to the identification of Mycobacterium tuberculosis and biomarker discovery

An adequate and effective tuberculosis (TB) diagnosis system has been identified by the World Health Organization as a priority in the fight against this disease. Over the years, several methods have been developed to identify the bacillus, but bacterial culture remains one of the most affordable methods for most countries. For rapid and accurate identification, however, it is more feasible to implement molecular techniques, taking advantage of the availability of public databases containing protein sequences. Mass spectrometry (MS) has become an interesting technique for the identification of TB. Here, we review some of the most widely employed methods for identifying Mycobacterium tuberculosis and present an update on MS applied for the identification of mycobacterial species.     

Day length and evening temperature predict circannual variation in activity duration of the colony of the Indian cliff swallow,Hirundo fluvicola

In avian species, circannual rhythms, in a number of biological variables, including locomotor activity, have been studied under both laboratory and natural environmental conditions. However, information on circannual rhythm in daily activity duration of Indian cliff swallow (Hirundo fluvicola) is not available. It is a communal mud nesting, non-migratory species and inhabits low under arch bridges. Although it figures in the IUCN Red List under the least concerned category, it is important to study its behavioral ecology that may be of utmost importance from conservation stand point. In the present investigation, we examined the circannual rhythm in daily activity duration in this species at a communal roosting site under Kharoon river bridge on the Raipur–Bhilai highway (21°15′07.54′′N; 81°32′30.65′′E), Raipur, India, for eight consecutive days, every month from August 2009 to October 2011. On each study day, observations were made in two sessions, morning and evening. We monitored and recorded emergence time of the first bird from the nest in the morning and entry time of the last bird to the nest in the evening. We also recorded the ambient temperature and humidity of the study site simultaneously. Average daily activity duration (the time difference between the first bird’s emergence time and the last bird’s entry time from/to the nest, respectively) was computed for each month. A significant circannual rhythm in activity duration was validated. The peak of activity rhythm occurred on 22nd June with a spread between 19th June and 25th June. The activity duration was the shortest in winter and the longest in summer. The daily activity duration was positively correlated to the day length, sunset time, and morning and evening temperatures; whereas negatively correlated with the sunrise time, and morning and evening humidity. The multiple linear regression models suggest that day length alone explains 96% of the total variance in activity duration, whereas only 0.5% variance was attributable to evening temperature. We conclude that the day length is the strongest predictor of circannual variation in daily activity duration of the colony of Indian cliff swallow; whereas the evening temperature has very little effect. Further, we recommend that comparable studies under natural conditions might be very helpful to explore the effect of environmental cues on other intriguing behavioral decisions made by this and other avian species.     

Opercular Activity and Temporal Organization of Surfacing Behaviour in Indian Catfishes,Clarias batrachus and Heteropneustes fossilis

Opercular and surfacing activity were observed in the Indian catfish Clarias batrachus and Heteropneustes fossilis. In the series A experiments, the opercular activity was monitored under two experimental conditions, viz., (1) surfacing allowed and (2) surfacing prevented. A statistically significant elevation of the rate of opercular activity was observed when air breathing was prevented in both species. In addition, a significant prevention effect and a time of day dependence of that were noticed in both species. In the series B experiments, temporal patterns of surfacing and air-gulping activities were examined under an artificial LD 12:12 schedule at 2-h intervals over a period of 48 h. The inter air-gulping interval in minutes between two consecutive bouts was also recorded four times each day in both species. A significant 24-h rhythm was found for the rate of surfacing activity and length of the inter air-gulping interval in both species. However, the overall activity appears to be much higher in Heteropneustes fossilis as compared to Clarias batrachus.     

Astaxanthin production from the green alga Haematococcus pluvialis with different stress conditions

Summary Haematococcus pluvialis was induced to produce the astaxanthin pigment. A factorial design was carried out with three sodium acetate concentrations, 0.025, 0.05, 0.1 (g/l), and three NaCl concentrations (0.1, 0.2 and 0.4 %).The best conditions in algal culture for astaxanthin production were 0.2 % NaCl, 0.025 g/l sodium acetate and 0.05 g/l sodium acetate, each a 3.0, 1.83 and 1.78 % of astaxanthin, production in base to total dry weight, respectively. The higher astaxanthin production by bioreactor was 18.6 mg/l in the condition with 0.2 % NaCl.     

Assessment of Pulmonary Function in Young and Elderly Shift Workers of a Steel Plant

The present investigation was undertaken to examine the effects of shift work on pulmonary function. 217 subjects from a local steel plant, volunteered for this study. Of these, 65 were day workers (DWs) and 152 were shift workers (SWs). Pulmonary function, such as vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in 1 second (FEV₁), peak expiratory flow rate (PEFR) and percent deviation of PEFR from the expected PEFR in each subject was measured between 09:00 to 11:00. Both day workers (DWs) and shift workers (SWs) were divided into two groups, based on age, i.e., ≤ 40 y and ≥ 41 y. The results indicate that the average levels of VC, FVC, FEV₁ and PEFR were significantly lower in older age in both DWs and SWs when compared to their younger counterparts. Although elderly shift workers had higher levels of VC, FVC and FEV₁ than day workers of comparable age, the difference was not statistically significant for FVC and FEV₁. In contrast, average value of PEFR was lower in older shift workers. Further, mean percent deviation of observed PEFR from the expected value was conspicuously low in elderly shift workers. In summary, shift work appears to accelerate age-related decline in PEFR at least in elderly shift workers. Results of multiple regression analysis and correlation analysis compliment this finding.