Inconspicuous endophytic bacteria mimicking latex exudates in shoot-tip cultures of papaya

Shoot-tip cultures of papaya (Carica papaya L.) cv. Surya were initiated from field-grown plants after extensive surface sterilization for their use in micropropagation and to assess endophytic bacterial associations with apparently clean cultures. Out of 150 explants cultured, 40% of them displayed microbial contamination with obvious colony growth on tissue culture medium during the first in vitro passage of 1 month. Among the apparently clean 90 cultures, 12% showed cloudiness of medium at the base of the explant resembling latex exudates. These 11 cultures, upon indexing, i.e., testing the cultures for any covert bacteria by transferring traces of tissue culture medium to enriched bacteriological media, revealed inconspicuously associated endophytic bacteria in them, whereas the remaining cultures that had clear medium proved to be index-negative. Each of the above 11 cultures yielded a single organism, which included 10 Gram-negative isolates (5× Ralstonia mannitolilytica, 2× Paenibacillus sp., 2× Sphingomonas sp., 1× Pantoea sp.) and 1 Gram-positive isolate (Lysinibacillus fusiformis) as per 16S rRNA gene sequence homology analysis. Up on inoculation of index-negative papaya cultures with the above organisms on Murashige and Skoog based tissue culture medium at 25 °C, all the endophytes except Pantoea sp. remained inconspicuous or non-detectable in vitro, and they affected the survival and growth of papaya cultures as per visual assessment. The organisms tended to grow actively on tissue culture medium and become expressive with increase in incubating temperature (30–37 °C) or with the supply of host tissue extract. The study has brought out that the hazy exudates from the explant often encountered with plant tissue cultures at culture initiation could be resulting from inconspicuously growing endophytic bacteria, with possible threat to various tissue culture applications. Early identification of such cultures through indexing helps in containing the problem, prevent lateral spread of contaminants and offer more security to in vitro germplasm and culture exchange. Tissue culture system also helped in isolating some novel endophytic bacteria associated with papaya shoot-tips.     

Micropropagation of Cymbidium Sleeping Nymph through protocorm-like bodies production by thin cell layer culture

Transverse thin cell layers (tTCLs) of protocorm-like bodies of two stages of PLBs (30 d and 60 d old) of Cymbidium Sleeping Nymph were used as explants to induce PLBs by using coconut water (CW) as a natural additive. 5% (v/v) CW supplemented to KC medium induced an average of 5 PLBs per responding tTCL of 30 d old PLBs with 83% of responding tTCLs. A low percentage of responding tTCLs were observed in 60 d old PLBs’ tTCLs. Anatomical and confocal microscopic studies traced the origin of PLBs to subepidermal layers of the tTCL. A significantly high percentage of shoot regeneration was obtained from PLBs formed on 1–10% (v/v) CW from tTCLs of 30 d old PLBs in comparison to PLBs induced on control after first subculture on KC medium (without CW). The induced PLBs regenerated into plantlets with velamenous roots and these plantlets were transferred to greenhouse conditions on cocopeat:perlite (9:1) with nearly 100% survival. Post-transfer performance of the plantlets was monitored. The results suggest tTCLs as potential explants (with respect to economy of precious hybrid materials) which can overcome the slow growth of hybrid PLBs and coconut water as a single natural additive for the mass multiplication of commercially important orchids.     

Study of muscle glycogen content in both sexes of an Indian teleost <Emphasis Type="Italic">Clarias batrachus</Emphasis> (Linn.) exposed to different concentrations of Arsenic

The present investigation has been conducted to study the effect of different sublethal concentrations of arsenic (5, 10 and 15 mg/L) on the muscle glycogen content in an Indian teleost, Clarias batrachus, during their post-spawning period (October to January).The species were exposed to various arsenic concentrations for six consecutive days i.e.,144 h. Significant differences in average muscle glycogen content were found in the treated male and female C. batrachus specimens. However, significantly higher (P < 0.01) muscle glycogen content was observed in male fish when compared to females in the untreated specimens. Arsenic caused muscle glycogenolysis in both sexes of C. batrachus. The depletions were not always dose (arsenic concentration) and time dependent, although higher concentrations were more glycogenolytic than the lower concentrations. After 96 h of treatment with arsenic, less depletion of muscle glycogen content was recorded in both sexes of fish.     

Enzymatic treatment and use of starters for the nutrient enhancement in fermented flour of red and white varieties of finger millet (Eleusine coracana).

Two varieties of finger millet (Eleusine coracana)-a tannin-containing red variety, CO13, and nontannin white variety, CO9-processed by treatment with enzymes (cellulase and hemicellulase) and fermentation with starters (from previously fermented finger millet batter), achieved the desirable goals of reduced fermentation time (12 h), increased acidity (2.2 to 2.4%), enhanced in vitro protein digestibility (IVPD) (14 to 26%), and mineral availability compared to 48 h uncontrolled natural fermentation (Usha Antony and Chandra, 1998). Fermentation with starters alone increased titratable acidity (1.02 to 1.88%), IVPD (5. 5 to 22%) and mineral availability, and decreased phytate (23 to 26%) and tannin (10.8 to 40.5%) in the millets. Enzymatic treatment (3 h, 50 degrees C) did not significantly alter the pH, phytate, tannins, IVPD, or HCl-mineral extractability but enhanced fermentative changes. Overall, the changes were marked when the 48 h starter was used and the improvements in nutrient availability was greater in the CO13 variety.     

An efficient method for extraction of astaxanthin from green alga Haematococcus pluvialis

Haematococcus pluvialis is one of the potent organisms for production of astaxanthin, a high value ketocarotenoid. Astaxanthin is accumulated in thick-walled cyst cells of Haematococcus. The thick cell wall is made up of sporopollenin-like material, algaenan, which hinders solvent extraction of astaxanthin. In the present study, an improved method for extraction of astaxanthin without homogenization of cells is reported. Extractability of astaxanthin from cyst cells was evaluated by treating cells with various solvents and pretreating the cells with organic and mineral acids at 70 degrees C followed by acetone extraction. Hydrochloric acid treatment facilitated 86-94% extractability of astaxanthin. Treatment time, temperature, and concentration of the acid were found to be critical factors for maximum extractability. The treatment did not affect the astaxanthin ester profile and the treated cells can be preserved until further use.     

Influence of Variable Amounts of Irrigation Water and Nitrogen Fertilizer on Growth, Yield and Water Use of Grain Sorghum

Sorghum hybrid CSH-6 was grown in fields in Delhi, India between July–November 1986 in order to study the effect of nitrogen nutrition and irrigation on dry matter accumulation, grain yield and water use. The treatments included 40 Kg Nha⁻¹ combined with two irrigations (30 DAS, 60 DAS), one irrigation (60 DAS) and no irrigation respectively. Rainfall during the crop season was only 17 cm. The unirrigated plants were considerably water stressed and exhibited very low leaf water potential, less leaf area, delayed anthesis, longer crop duration but shorter grain filling duration. The ears showed sterility and yield was only 0.41 t ha⁻¹ without nitrogen fertilization. Addition of nitrogen fertilizer had no significant effect on yield in unirrigated plants. A single irrigation 60 DAS increased yield due to increase in both grain number and grain weight per ear in fertilized and unfertilized crop respectively. Two irrigations in the unfertilized crop increased the yield to 2.2 t ha⁻¹ while similar treatment in the fertilized crop did not increase the yield significantly. Irrigation increased the WUE for grain yield. The results indicate that nitrogen stress and water stress reduced grain yield primarily through grain number rather than grain weight. Irrigation relieved both water stress and nutrient stress. Nitrogen nutrition was not beneficial under severe water stress conditions but was considerably helpful under mild stress. Biomass, grain yield and harvest index show significant correlation with preanthesis water use.     

A note on the relationship between the production rates of volatile fatty acids and their concentration,digestible organic matter and total digestible nutrient intake in buffalo calves

Volatile fatty acid (VFA) production rates were measured by isotope dilution technique in the rumen of buffalo calves fed on wheat straw plus concentrate, green maize, cow pea and berseem. Correlations derived between the VFA production rates and their concentration and DOM were significant except in animals fed on cow pea. The VFA production rates were also significantly correlated with the TDN intake in all the four feeds tested.The regression equations obtained for the four feeds were different, which suggested that VFA production may vary with the quantity and quality of feed digested. These experiments suggest the use of different regression equations for different feeds.     

Morphometric and developmental consequences in Spodoptera litura due to feeding on three varieties of sweet potato plants (Ipomoea batata)

The tobacco caterpillar, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae), is a polyphagous pest defoliating sweet potato, Ipomoea batata (Lam) (Convolvulaceae), throughout Asia. The study of morphometric parameters of S. litura as a result of feeding on three varieties (RNSP1, KIRAN and RNSP3) of host plant revealed that a greater number of egg masses were laid on the KIRAN variety than on the others. I. batata varieties showed statistically significant effects on length, breadth and weight of different larval instars. KIRAN-fed larvae molted to bigger-sized pupae. S. litura larvae reared on KIRAN variety had the highest feeding index as well as growth index. The low concentrations of phenols and carbohydrates coupled with elevated levels of proteins and amino acids were found in KIRAN as compared with RNSP1 and RNSP3. Collectively, the results of this study revealed that KIRAN cultivar was the most suitable food plant for the development of S. litura. Concurrently, it is suggested that this cultivar is therefore least suitable for sweet potato cultivation.