A study of the pollen grains of Amaranthus spinosus Linné and A. Dubius Mart ex Thellung and their hybrids

A pollen-morphology study of Amaranthus spinosus, A. dubius, and their hybrids has been carried out. Three pollen types have been observed, namely (1) Type A: micrograins; (2) Type B: grains with smaller pores; and (3) Type C: grains with larger pores. Type B is characteristic of A. spinosus, Type C of A. dubius, and the micrograins of the hybrids. Pollen size range, and frequency of the various morphotypes serve to throw light on the biosystematics of the plants studied.     

Effect of ethrel and chloroethanol on pea diamine oxidase activity

The activity of cotyledon and embryo diamine oxidase was reduced by feeding ethrel and chloroethanol to the seedlings. The inhibitory effect of 2,4-D on the activity of enzyme in the cotyledon which may be mediated through ethylene was reversed by exposure of seeds to red light.     

Effect of some nitrogenous salts on nitrogen transfer and protease activity in germinatingZea mays L. seeds

Maize seeds were allowed to germinate in the presence of different nitrogenous salts for 72 h. Changes in the ethanol soluble and insoluble nitrogen were studied in the embryo and in the endosperm. Supply of Ca(NC₃)₂ enhanced germination and protease activity in the endosperm resulting in greater solubilisation of protein to soluble nitrogen in the seeds. NH₄NO₃ and (NH₄)₂SO₄ were less effective as compared to Ca(NO₃)₂. Cycloheximide inhibited germination and protease activity. Pretreatment also resulted in increase in growth, soluble and insoluble nitrogen, and nitrate reductase activity in the primary leaves. Ca(NO₃)₂ was more effective than NH₄NO₃ and (NH₄)₂SO₄.     

Modification of the rapidly reacting thiols of atrial and ventricular myosins. Evidence for structural variances around the SH-1 thiol of the two isozymes

Environmental variances were noted around the rapidly reacting SH-1 thiol of ventricular versus atrial myosin, based on electron paramagnetic resonance studies. Further studies, in which either SH-1 or SH-1 + SH-2 thiols were modified with N-ethylmaleimide, indicated the importance of the SH-2 moiety of both isozymes for generation of tension, when analyzed as synthetic actomyosin threads. Comparative EPR studies showed that the spin label was more strongly immobilized when complexed to ventricular SH-1 thiol as compared to when it was complexed to atrial myosin. Likewise, addition of PPi, ATP or ADP created a greater mobility in the spin label when added to ventricular spin-labeled myosin as compared to that of atrial myosin. comparative studies of spin-labeled actomyosin versus myosin analyzed at different EPR power settings also demonstrated disparaties surrounding the SH-1 thiol between the two myosin isozymes.     

Modulatory effects of metanil yellow on immunity in rodents.

Pathomorphological and immunological studies were carried out on rodents following oral administration of 0, 0.1, 0.25 and 0.5% (w/w) metanil yellow, mixed in diet, for 30 days. No significant change in hematologic parameters and histologic architecture of liver, kidney, mesenteric lymph node, thymus and urinary bladder was observed except for mild desquamation of intestinal villi and moderate changes in Peyer's patches of small intestine with higher doses. Among immunological parameters, significant enhancement in the primary humoral immune response (anti-SRBC IgM plaque forming cells of spleen) was observed with the lowest dose of metanil yellow while higher doses produced opposing effects. An elevated cutaneous delayed type hypersensitivity (DTH) reaction to SRBC was seen in 0.1% metanil yellow treated animals but higher doses did not influence the reaction. The treatment also caused changes in functional capabilities of macrophages. Although these immune alterations could hardly influence the local immunity of gut, as measured by the capacity of animals to cause rejection of Nippostrongylus brasiliensis parasite, the potential to modulate the immunity in general by metanil yellow however assumes considerable biological significance.     

Extractive lactic acid fermentation using ion-exchange resin

Lactic acid fermentation is an end-product-inhibited reaction. The restriction imposed by lactic acid on its fermentation can be avoided by extractive fermentation techniques. Studies were performed by attaching an ion-exchange resin packed column with a 2-L fermentor for separation of lactic acid. The fermentation, in a conventional batch mode, resulted in a lactic acid yield of 0.828 g . g(-1) and a lactic acid productivity of 0.313 g . L(-1) . h(-1). However, these could be further enhanced to 0.929 g . g(-1) and 1.665 g . L(-1) . h(-1) by extractive fermentation techniques. The effect of temperature on extractive fermentation was remarkable and has been included in this work.     

Differential actions of corticosterone on luteinizing hormone and follicle-stimulating hormone biosynthesis and release in cultured rat anterior pituitary cells: interactions with estradiol

Previous in vivo studies from our laboratory suggested that glucocorticoids antagonize estrogen-dependent actions on LH secretion. This study investigated whether corticosterone (B) may have similar actions on gonadotropin biosynthesis and secretion in vitro. Enzymatically dispersed anterior pituitary cells from adult female rats were cultured for 48 h in alpha-modified Eagle's medium containing 10% steroid-free horse serum with or without 0.5 nM estradiol (E2). The cells were then cultured for 24 h with or without B in the presence or absence of E2. To evaluate hormone release, 5 x 10(5) cells were incubated with varying doses of GnRH (0, 10(-11)-10(-7) M) or pulsatile GnRH (10(-9) M; 20 min/h) for 4 h. Cell and medium LH and FSH were measured by RIA. To evaluate LH biosynthesis, 5 x 10(6) cells were incubated for an additional 24 h with 10(-10) M GnRH, 60 microCi 3H-glucosamine (3H-Gln), 20 microCi 35S-methionine (35S-Met), and the appropriate steroid hormones. Radiolabeled precursor incorporation into LH subunits was determined by immunoprecipitation, followed by SDS-PAGE. Continuous exposure to GnRH stimulated LH release in a dose-dependent manner, and this response was enhanced by E2. B by itself had no effect on LH release, but inhibited LH secretion in E2-primed cells at low concentrations of GnRH (10(-10) M or less). Total LH content was not altered by GnRH or steroid treatment. Similar effects of B were observed in cells that were given a pulsatile GnRH stimulus. In contrast to LH, E2 or B enhanced GnRH-stimulated FSH release at the higher doses of GnRH, while the combination of E2 and B increased basal and further augmented GnRH-stimulated release. Total FSH content was also increased in the presence of B, but not E2 alone, and was further augmented in cells treated with both steroids. There were no effects of the steroids on the magnitude of FSH release in response to GnRH pulses, but the cumulative release of FSH was greater in the E2 + B group compared to controls, indicating an increased basal release. Independent of E2, B suppressed the incorporation of 3H-Gln into LH by more than 50% of control, with only subtle effects on the incorporation of 35S-Met.(ABSTRACT TRUNCATED AT 400 WORDS)     

In vitro propagation of Coleus forskohlii Briq., a threatened medicinal plant

In vitro clonai multip1ication of Coleus forskahlii Briq a threatened plant, has been achieved on MS medium supplemented with Kn (2.0 mg/l) and IAA (1.0 mg/l) using nodal segments as explants, Shoots multiplied at a rate of 12 — fold every six weeks. Rooting was achieved upon transfer of shoots onto MS medium containing IAA (1.0 mg/l). The micropropagated plants were successfully established under field conditions. Forskolin content in tubers of plants obtained by micropropagation was found to be 0.1%, the same as that found in wild plants. This micropropagation procedure should be useful for conservation as well as production of this important plantAbbreviations BAP 6-benzylaminopurine - IAA indole-3-acetic acid - IBA indole-3-butyric acid - Kn Kinetin - MS Murashige and Skoog (1962) basal medium - NAA -naphthalene acetic acid     

Cotugnia digonopora: Transport of leucine

The uptake of leucine through the tegument of Cotugnia digonopora, a cestode found in the fowl intestine, occurs by a process of active transport. The K_t of transport is 0.87 mM and the V_max is 0.223 μmol/min/g. Uptake of the amino acid is competitively inhibited by valine (K_t = 1.30 mM). Potassium cyanide and 2,4-dinitrophenol do not completely block the entry of leucine into the parasite.