Influence of Shading on the Gross Composition of Cuscuta Species on Medicago sativa

A study was made of the alterations in growth characteristics of Cuscuta Campestris, Cuscuta indecora and Cuscuta reflexa on Medicago sativa as a consequence of a limitation in light intensity. There was a decrease in the content of dry solids, protein and total phosphorus in the filament mass. A decrease in these parameters occurred also in the tissues of the host, but was less pronounced that in the parasite. The response by the host to parasite growth was not always the same in the shade as in light. Phosphorus showed a distinct tendency toward firm retention in the infection complex in the dark.     

EFFECTS OF LIGHT ON CYCLIC GMP METABOLISM IN RETINAL PHOTORECEPTORS

Abstract— Guanylate cyclase activity of dark-adapted bovine rod outer segments demonstrates a biphasic pattern upon exposure to light. By 10 s of illumination, activity is 20% lower than that observed in dark-adapted outer segments. Activity subsequently increases and then slowly declines to two-thirds of the original activity after 10 min of illumination. In the presence of GTP or ATP, hydrolysis of cyclic GMP is rapidly enhanced by exposure of outer segments to light; the magnitude of this effect is dependent on the amount of substrate present. The rapid effects of light on synthesis and degradation of cyclic GMP indicate that these reactions may be involved in the visual process. The concentration of guanosine 3':5'-cyclic monophosphate (cyclic GMP) is extraordinarily high in dark-adapted bovine rod outer segments and is at least 100-fold that of adenosine 3':5'-cyclic monophosphate (cyclic AMP). No significant decrease in the level of cyclic GMP or cyclic AMP was observed however upon exposure of dark-adapted outer segments to light.     

Phenol oxidase in the blood cells of millipedes

The nature and properties of the phenol oxidase present in the blood cells and plasma of three species of millipedes, Thyropygus poseidon, Polydesmus species, and Spirostreptus asthenus, have been investigated using a number of substrates as well as activators and inhibitors. The enzyme is located in the granular haemocytes. In the in situ condition it oxidizes diphenols, polyphenols, and also tyrosine. But when extracted from the homogenate of blood cells it showed only diphenolase activity. There is evidence of phenol oxidase activity in the plasma, but it did not act on tyrosine. The results obtained have been discussed in the light of previous work. It is suggested that the cell enzyme may have two sites of activity responsible for the oxidation of diphenol and also tyrosine. The observation that the monophenol oxidase activity is absent when the enzyme is extracted and isolated suggests that one of the sites of activity of the enzyme may be destroyed in the process of extraction.     

Transposon Tn5supF-based reverse genetic method for mutational analysis of Escherichia coli with DNAs cloned in lambda phage.

An efficient method for systematic mutational analysis of the Escherichia coli genome was developed. It entails Tn5supF transposition to lambda-E. coli hybrid phage clones (Kohara library) and then transduction of recipient cells to Sup+. Essential and nonessential genes are distinguished by the ability of insertion mutant phage to form haploid versus only heterozygous partial diploid bacterial recombinants.     

Thrombin cleavage analysis of a novel antihaemophilic factor variant, factor VIII delta II

Factor VIII delta II is a genetically engineered deletion variant of factor VIII expressed by recombinant Chinese hamster ovary cells, in which a major portion of the central (B) domain and a part of the light chain (Pro771-Asp1666) are missing. After immunoaffinity purification, the kinetics of thrombin cleavage of the novel molecule was analysed by SDS/PAGE, Western blotting and N-terminal amino acid sequencing. Thrombin first cleaves factor VIII delta II at Arg740-Ser741 to generate the 90-kDa heavy chain and an 80-kDa fusion polypeptide consisting of the remaining portion of the B domain and the 73-kDa light chain. The 90-kDa fragment is further cleaved, giving rise to 50-kDa and 40-kDa fragments while the 80-kDa fragment generates a 71/73-kDa doublet. The 71/73-kDa doublet, 50-kDa and 40-kDa fragments were further analysed by N-terminal amino acid sequencing and found to correspond to the predicted amino acid sequences. Our study shows that, in spite of the 900 amino acid deletion present in factor VIII delta II, the essential structural elements required for thrombin activation are conserved.     

Pharmacokinetics of growth hormone secretion in humans induced by growth hormone releasing hormone

This investigation compares the age- and sex-related changes in growth hormone (GH) response to growth hormone releasing hormone (GHRH) in normal subjects using an appropriate pharmacokinetic model. Twenty-five subjects (14 males and 11 females) aged 23-89 yr received a single intravenous bolus dose (1 microgram/kg) of GHRH-40 solution. Plasma GH concentration-time profiles are best characterized by a biexponential equation (or one-compartment model) with first-order release and disappearance rates and an equilibration lag time. The harmonic mean release rate half-life is similar for both sexes (males: 12.6 min vs. females; 11.4 min) but significantly different across age groups (23-35 yr: 7.2 min vs. 50-89 yr: 16.8 min). The mean disappearance rate half-life and GHRH-equilibration time lag for females (33.6 and 20.4 min, respectively) and the higher age group subjects (32.4 and 21.6 min, respectively) are significantly longer than those of males (22.8 and 9 min, respectively) and the lower age-group subjects (21.6 and 8.4 min, respectively). The mean metabolic clearance rate of GH is significantly lower (p less than 0.02) for females than for males (3.1 vs. 4.83 ml/hr.m2). However, the production rate and the amount of GH released by the pituitary for our subjects appear to be very similar for both males (8.7 micrograms/hr.m2 and 4.65 micrograms/m2) and females (9.33 micrograms/hr.m2 and 5.11 micrograms/m2).     

Measurement of the change in aerosol size distribution with bacterial growth in a pilot scale fermentor

A number of industrial processes require the addition of materials to the fermentation broth that are hazardous to health and environment. Agitation of broths inoculated with microorganisms can potentially release aerosols large enough to carry the microorganisms. The influence of agitation, air flow, and bacterial growth on aerosol size distribution, air flow, and bacterial growth on aerosol size distribution was investigated in an industrial pilot scale fermentor. A decrease in particle concentration was observed with increase in bacterial growth; this change was more pronounced in the size range above 2 mum. The aerosol size distribution was found to be practically independent of air flow rate and agitation rate for sizes less than 2 mum. However, for particles largar than 2 mum, the concentration was found to increase with an increase in air flow rate and agitation rate.     

Transcriptomic Profiling of Lathyrus sativus L. Metabolism of β-ODAP,a Neuroexcitatory Amino Acid Associated with Neurodegenerative Lower Limb Paralysis

Plant Molecular Biology Reporter - Grass pea (Lathyrus sativus L.) is a unique potential crop for marginal arid regions with untapped, exceptional biotic/abiotic stress tolerance, and high protein...     

Synaptic efficacy shapes resource limitations in working memory

Working memory (WM) is limited in its temporal length and capacity. Classic conceptions of WM capacity assume the system possesses a finite number of slots, but recent evidence suggests WM may be a continuous resource. Resource models typically assume there is no hard upper bound on the number of items that can be stored, but WM fidelity decreases with the number of items. We analyze a neural field model of multi-item WM that associates each item with the location of a bump in a finite spatial domain, considering items that span a one-dimensional continuous feature space. Our analysis relates the neural architecture of the network to accumulated errors and capacity limitations arising during the delay period of a multi-item WM task. Networks with stronger synapses support wider bumps that interact more, whereas networks with weaker synapses support narrower bumps that are more susceptible to noise perturbations. There is an optimal synaptic strength that both limits bump interaction events and the effects of noise perturbations. This optimum shifts to weaker synapses as the number of items stored in the network is increased. Our model not only provides a circuit-based explanation for WM capacity, but also speaks to how capacity relates to the arrangement of stored items in a feature space.