Responses of two differentially sensitiveCicer arietinum L. cultivars to water stress: Protein content and drought resistance

Two cultivars ofCicer arietinum L. with contrasting sensitivities to water stress, cv. C 214 (relatively resistant) and cv. 130 (susceptible) were compared for their protein content and soluble nitrogen (sol-N) under water stress. During water stress shoots of the cv. C 214 showed an increase (over the control) in both protein and sol-N content. The total nitrogen (total-N) also increased in the cv. C 214 while remaining almost unaffected in the cv. G 130. Cultivar C 214 shoots recorded lower protein/sol-N ratios. The results have been discussed in relation to resistance to water stress.     

STUDIES ON LYMPHOCYTES

Continuous extracorporeal irradiation of the circulating blood (ECIB) of from 3 to 501/2 hr duration was used to study in the calf the differential depletion of lymphocytes from spleen, lymph nodes and thymus as compared to blood and thoracic duct lymph. The cell content of tissues was measured by planimetry and/or test point analysis. Lymphocyte depletion by ECIB from various lymphoreticular organs, and from different areas within a given organ, was less than in the circulating blood or the thoracic duct lymph and varied from one site of a lymphoreticular organ to another. The degree of depletion with time followed an exponential function with at least two components. The first component corresponded to a relatively rapid fall and the second to a very slow reduction in lymphocyte content. The former is related to the elimination of an easily mobilizable pool of lymphocytes while the latter corresponds to a more sessile mass of lymphocytes which exchange with blood lymphocytes very slowly. Elimination of the easily mobilizable pool of lymphocytes by ECIB from all tissues studied was observed within 10–15 hr, indicating that the rate of exchange with blood is similar for this group of cells in various lymphoreticular tissues. The size, however, of the easily mobilizable vs the more sessile pools of lymphocytes may vary considerably, the best estimates for the former being as follows (in per cent of total lymphocyte mass): lymph node medulla, less than 10%; lymph node cortex plus paracortical zone, 18% (depletion mainly paracortical); red pulp of the spleen, 37%; densely populated white pulp of the spleen, 55%; and loosely populated white pulp of the spleen, 60%. In comparison, the approximate fractions of lymphocytes originating fromthe easily mobilizable pools in various lymphoreticular tissues plus the cells already circulating a t the onset of EClB correspond to 64% for the thoracic duct lymph and 78% for the circulating blood respectively. These findings are discussed in relation to production, recirculation and life span of lymphocytes, and immune reactions.     

Umsatz von Lymphozyten in Blut und Lymphknoten der Ratte

Summary Mature spermatozoa from the seminal vesicles of adult Agriolimax reticulatus have been studied by means of phase contrast and electron microscopy; sperm were either live, or sectioned or mounted whole and shadowed with gold. The cell is of the typical pulmonate sperm type with a simple acrosome and a spiral nucleus comprising the head, and a tail which is ensheathed along its entire length by mitochondrion. The 9 peripheral fibrils of the axial complex show no indication of a double nature. Within the spermatheca or gametolytic gland breakdown of sperm occurs; the nucleus and axial fibre bundle of the flagellum survive the longest. The complexity of the flagellum and the relative simplicity of the acrosome are discussed in light of the ecology of the spermatozoa. Many problems concerning the functional physiology of the sperm organelles remain to be investigated.     

Amoeba-bacteria relationship: Factors in the bacterial lipids supporting the growth of axenicEntamoeba histolytica

Live bacteria in modifiedDiamond’s axenic medium did not support growth ofEntamoeba histolytica. Cysteine hydrochloride, required for the multiplication of amoeba, was broken down by live bacteria and toxic substances were produced which were lethal for amoebae. Monoxenic and xenic cultures ofaxenically grownE. histolytica could be established in Boeck and Drbohlav medium with bacteria and rice starch. Bacterial lipids prepared from 15 human intestinal bacteria supported growth and multiplication ofE. histolytica in axenic medium. In a pilot experiment using lipids ofStreptococcus faecalis, free fatty acids did stimulate the multiplication of amoebae. When total lipids of this bacteria were fractionated into neutral lipids and phospholipids by chromatography and used, neither fraction was found to stimulate growth. Free fatty acids prepared by chemical hydrolysis of the total lipids, neutral lipids and phospholipids stimulated growth ofE. histolytica, The sterols present in the bacterial lipids (neutral lipids or non-saponifiable fractions) stimulated growth of amoebae. It was found thatE. histolytica is incapable of liberating fatty acids from di- or triglyceridesof phospholipids and the multiplication of the organism is stimulated by the presence of free fatty acids and sterols (cholesterol).     

Histophysiology of the pituitary gland in correlation with the ovarian cycle in Tor (Barbus) tor (Ham.)

Summary The histophysiology of the pituitary gland has been studied in correlation with the phases of the ovarian cycle in Tor (Barbus) tor. The cyanophilic cells in the proximal pars distalis display changes related to stages in the maturation of the ovary. The cyanophils, which display hypertrophy and hyperplasia and undergo degranulation and vacuolation during maturation, prespawning, and spawning periods, are identified as gonadotrops. Apparently their glycoproteinaceous contents, gonadotropin(s), control the processes of vitellogenesis, ovarian maturation, and initiation of oviposition. Depletion of glycoproteinaceous contents in these cyanophils leads to atresia of oocytes at advanced stages, but it does not appear to interfere with oogonial proliferation. The neurosecretory materials are implicated in female reproduction.I am deeply indebted to Professor H. Swarup for suggesting and supervising this study and to Dr. Grace E. Pickford for her generosity in sending me xerox copies of some articles.     

Colony interactions and mycoparasitism betweenAcremonium furcatum andAspergillus spp.

Summary Colony interactions and mycoparasitism betweenAcremonium furcatum and ten species of Aspergillus were studied in dual cultures. It was observed thatA. furcatum overgrew the colonies of all the ten species of Aspergillus studied. During the mycoparasitic interactions frequent coiling, penetration and growth of hyphae ofA. furcatum inside the conidiophores of six species of Aspergillus were observed.     

Free proline accumulation and drought resistance inCicer arietinum L.

Two cultivara ofCicer arietinum L. with different sensitivity to drought in the early vegetative stage were compared for their capacity to accumulate proline when subjected to water stress. Both shoots and roots of the two selected cultivara accumulated proline under water stress and this effect increased with increase of water stress level. A high positive correlation between free proline and water saturation deficit (WSD) was recorded while these two factors were negatively correlated to the dry weight of the shoot. Also effects of duration of stress on proline accumulation patterns in relation to drought resistance have been shown.     

Growth characteristics and proline content in relation to water status in twoZea mays L. Cultivars during rehydration

Growth behaviour, proline changes and water saturation deficit (WSD) changes were studied in two maize cultivars, Agati-76, a drought resistant oultivar, and cv. Vijay, a susceptible one after stress conditions were removed. Plants of both the cultivars showed a tendency to recover during rehydration. Phenotypically the plants appeared just normal on 7th day of rehydration, although recovery was never complete. Significant positive correlation existed between free proline content and concomitant change in water saturation deficit. Significantly higher proline content in cv. Agati-76 was reoorded in cv. Vijay, immediately after the stress was released, thereafter continuous decline was observed up to 7th day of rehydration in both the cultivars. Proline changes in relation to recovery of plants from stress conditions are discussed.     

Purification and some properties of inducible N-acetylglucosamine kinase from Candida albicans

N-Acetylglucosamine kinase (ATP:2-acetamido-2-deoxy-D-glucose 6-phosphotransferase, EC 2.7.1.59) catalyzes the first reaction in the inducible N-acetylglucosamine catabolic pathway of Candida albicans, an obligatory aerobic yeast. As a part of continuing biochemical studies concerning the regulation of gene expression in a simple eukaryote, N-acetylglucosamine kinase has been purified and characterized biochemically. The enzyme has been purified about 300-fold from the crude extract and its molecular weight of 75 000 has been determined by Sephadex G-100 gel filtration. Isolation and analysis procedures are described. The kinase reaction is optimal within a pH range of 7--8. The enzyme is strictly specific for GlcNAc as phosphate acceptor; ATP is the phosphoryl group donor for the kinase reaction and to a lesser extent dATP and CTP. Km values for GlcNAc and ATP are 1.33 mM and 1.82 mM, respectively. The enzyme required Mg2+, which may be replaced by other bivalent metal ions such as Mn2+, Ca2+, Ba2+ and Co2+ for a lesser degree of effectiveness. The purified enzyme is extremely sensitive to thermal denaturation and becomes completely inactive by heating at 65% C for 2 min. The enzyme is also inactivated by sulphydryl reagents such as p-chloromercuribenzene sulfonic acid and N-ethylmaleimide.