Colonization of Serratia fonticola on phylloplane of tomato and its impact on leaf cytoplasmic protein profile

Aim: The aim of the present study was to understand the impact of human enteric pathogen (Serratia fonticola) colonization on cytoplasmic protein profile of tomato leaves. Methodology: Aseptically grown plants were inoculated with S. fonticola and sampled at different interval of time. Colonization pattern was studied by leaf impression technique. Changes in cytoplasmic protein profile were studied by protein-protein crosslinking method followed by separation through SDS PAGE. Results: The colonization pattern study revealed that maximum colonies were found at 24 hr post inoculation which gradually decreased with time, showing the survival of the pathogen on phylloplane. Electrophoretic separation of cytoplasmic proteins showed crosslinking of some proteins in treated samples at 48, 72 and 96 hr post inoculation. Interpretation: This study will help in understanding the molecular changes in cytoplasmic protein profile and survival of pathogen on phylloplane, thus limiting the growth of bacteria, Serratia fonticola on phyllosphere.

Effect of vitamin A excess on germ cell development in prepubertal rat testis.

Vitamin A in graded doses of 125, 250 and 375 U.S.P./kg body wt, po, for 10 days (d 21-30) drastically reduced the testicular weight by 25 to 62% and seminiferous tubular diameter by 14 to 35% in prepubertal rats in lowest and highest doses of the treatment. The treatment induced disproportionate enlargement of nuclei and cytoplasm of the germ cells; predominantly the preleptotene and pachytene spermatocytes. These abnormal germ cells, often with 2 or 3 nuclei displayed vacuolated cytoplasm surrounding pyknotic or granulated or dispersed chromatin granules within the nuclei in a dose proportionate manner. The round spermatids were the most sensitive cell types which completely disappeared in two higher doses of treatment. Vacuolation of Sertoli cell cytoplasm in about 25% of the tubules with associated increase in intertubular space was also observed in rats treated with the highest dose of the vitamin. Circulatory levels of FSH, LH and testosterone remained unaltered following the vitamin excess treatment. Therefore, it is suggested that excess vitamin A even for shorter duration like the present one is detrimental to developing cell types and prevents the progress of the spermatogenic process beyond the round spermatid stage.

Regulatory role of cortisone and dietary carbohydrate energy in prepubertal rat mammary gland growth and development.

Role of cortisone and regulated carbohydrate energy in mammary gland growth, based on studies of morphometric and certain growth and energy related biochemical parameters has been evaluated in the adrenalectomized prepubertal female rat. Results showed improvement or restoration of mammary features like fat pad weight, area, duct system and sprouting of end and lateral buds by cortisone treatment from adrenalectomy induced suppressed state. Similarly the hormone rectified the gland nucleic acids, glycogen and rate of tissue oxidation of glucose levels, reduced under adrenalectomy. Adrenalectomy caused loss of appetite (33.5% less than normal intake). This amount of diet restriction to normal intact did not affect the gland morphology but reduced nucleic acids, protein, glycogen and glucose oxidation rate. Provision of dextrose mixed diet to the adrenalectomized rats showed variable improvements of these biochemical parameters except the gland protein level in association with increase in appetite. However, cortisone therapy under provision of dextrose supply, restored gland protein level and increased further in nucleic acids, glycogen and glucose oxidation rate. The morphological growth parameters with dextrose and cortisone also showed further improvements. Results suggested that glucocorticoid was essential mammary growth factor during prepubertal ages. The hormone appeared to operate via tissue metabolism and stimulating energy intake through appetite stimulation.

Role of adrenal in establishment and development of conceptus in unilaterally ovariectomized mated rats.

The model of unilateral ovariectomy induced ovarian compensatory hypertrophy in mated bilaterally adrenalectomized rats was used to assess the role of adrenal in conceptus development. Replacement dose of dehydroepiandrosterone (DHA) or corticosterone (Comp. B) from day 2-14 post coitum was given with or without ip injections of estrogen (E, on day 2) and progesterone (P, on day 3 or 3-9). Replacement of adrenal hormones failed to support ipsilateral uterine horn (IP) pregnancy. But injections of E2 and P support IH pregnancy in variable percentages (about 38-75%) of rats depending on the type of adrenal steroids and single or multiple doses of P. Contralateral horn (CH) pregnancy developed under any of these conditions. Adrenalectomy induced reduction of fetal weight and pregnancy index (No. of fetus divided by No. of implantation sites), were not significantly improved by adrenal hormone replacement, except pregnancy index of those animals which received Comp. B and P. Adrenalectomy inhibited compensatory increase of contralateral corpus luteum (CL) volume and ovarian delta 5(3)beta-hydroxy steroid dehydrogenase (delta 5(3)beta-HSD) activity. Replacement of DHA or Comp. B induced these compensatory changes. Comp. B and P appears to be a better combination in establishment of IH pregnancy, pregnancy index maintenance and stimulation of ovarian compensatory changes. Results suggest that adrenocorticoids were not obligatory for conceptus development but were important for efficient action of ovarian steroids in establishment and maintenance of pregnancy. Relationship between nutrition or pituitary gonadotropins and adrenal steroids, having relevance to conceptus development has been discussed.

Need of dietary energy at critical implantation time when local ovarian hormones are obligatory for conceptus development.

Role of dietary energy and local ovarian hormones in conceptus development in the rat was evaluated by giving ip injections of estrogen and progesterone under diet restricted and/or dextrose supplemented conditions, using the experimental model of ovarian compensatory hypertrophy. Replacement of estrogen on day 2 and progesterone on day 3 was necessary for conceptus development in the ipsilateral uterine horn after unilateral ovariectomy on day 2. Continuation of progesterone injection up to day 9 improved the percentage of conceptus development. Conceptus development was normal when unilateral ovariectomy was performed after day 2 of pregnancy. Compensatory increases in corpus luteum (CL) volume and the activity of delta 5 3 beta-hydroxy steroid dehydrogenase (3 beta-HSD) in contralateral ovary were observed after unilateral ovariectomy on day 2-4 of pregnancy. However, 70% diet restriction reducing the energy intake (from 90 to 27 kcal/rat/day) abolished the single dose hormone therapy effects in ipsilateral horn conceptus development and also reduced the effects of continued progesterone, percentage of contralateral horn conceptus development, compensatory changes in the CL volume and delta 5 3 beta-HSD activity of the contralateral ovary. However, dietary dextrose supplementation (increasing calorie intake from 27 to 56 kcal/rat/day) significantly improved/restored hormone response for conceptus development, compensatory changes of the CL volume and enzyme activity in contralateral ovary. The results suggest that day 2-3 of pregnancy is the critical time when local ovarian supply of estrogen and progesterone are obligatory for establishment and conceptus development in the rat. During this period adequate mobilizable source of energy is necessary for execution of hormonal message.

Involvement of dietary glucose in adrenal steroidal regulation of spermatogenic and steroidogenic activities in prepubertal rat testis.

Effects of dietary and supplemented dextrose energy on the role of corticosterone (Comp. B) or dehydroepiandrosterone (DHA) in spermatogenic and steroidogenic activity in the bilaterally adrenalectomised prepubertal rat testis were studied. Adrenalectomy reduced the body and testis weight, numbers of the stage VII cell types [spermatogonia A (A), preleptotene (PL) and pachytene (P) spermatocytes and step 7 spermatid (7)], testicular delta 5-3 beta-hydroxysteroid dehydrogenase (delta 5-3 beta-OH-SDH) activity and serum testosterone. Adrenalectomy also caused reduction of energy intake due to loss of appetite which was stimulated by hormone replacement therapy. Treatment of adrenalectomised rats with DNA or corticosterone enhanced the spermatocyte population and the enzyme activity, especially after 30 days of age. Dextrose supplementation with hormone treatment however, did not produce significant additive effect on stage VII cell counts, but delta 5-3 beta-OH-SDH activity showed additive effect in this age group. Results suggest that adrenal steroids regulate testicular steroidogenesis and spermatogenesis during the prepubertal ages by modifying the supply of dietary glucose.

Cyclic peptides––Small and big and their conformational aspects.

Cyclic peptides form an interesting class of compounds for study by conformational analysis, by virtue of their unique conformational features and biological properties. The small cyclic peptides having 3–6 peptide units in their ring, show a variety of conformational characteristics such as occurrence of cis peptide units, flexibility of peptide dimension and variety in hydrogen bonding. The different possible conformations of cyclic triand hexa-peptides are given and certain specific conformational features are discussed for cyclic tetra and pentapeptides. For higher cyclic peptides, the hydrogen bonding requirement for stability of the backbone of the ring, is seen to be kept to a minimum. These various features and their significance are examined and discussed in the light of energy minimization studies and analysis of available experimental data.