Commercial raw materials from algaculture and natural stocks of Ulva spp.

Journal of Applied Phycology - Ulva species have potential uses in several industrial sectors as they are rich in proteins, vitamins, fibers, and minerals. They also produce the essential amino...     

Diet of the snake Philodryas nattereri (Steindachner, 1870) suggests a high plasticity of foraging in north-eastern Brazil

The knowledge about interactions between predators and prey is essential for understanding the natural history of animals, especially snakes, which are cryptic organisms that are difficult to visualize in the wild. This article reports on the predation of lizards, frogs, bats and venomous snakes by the snake Philodryas nattereri, evidencing its generalist feeding habits.     

Biosynthesis of Callose and Cellulose by Detergent Extracts of Tobacco Cell Membranes and Quantification of the Polymers Synthesized in vitro

The conditions that favor the in vitro synthesis of cellulose from tobacco BY-2 cell extracts were determined. The procedure leading to the highest yield of cellulose consisted of incubating digitonin extracts of membranes from 11-day-old tobacco BY-2 cells in the presence of 1 mM UDP-glucose, 8 mM Ca2+ and 8 mM Mg2+. Under these conditions, up to nearly 40% of the polysaccharides synthesized in vitro corresponded to cellulose, the other polymer synthesized being callose. Transmission electron microscopy an...     

Analysis of alloantisera against bovine lymphocytes. Joint report of the 1st International Bovine Lymphocyte Antigen (BoLA) Workshop

The results and agreements of the 1st international BoLA workshop, held in Edinburgh, Scotland in August 1978, are reported. Most of these concern the results from a comparison test of 249 alloantisera to bovine lymphocytes, the antisera being contributed by 9 laboratories. These sera were compared directly in Edinburgh on a panel of lymphocytes from 130 cattle of 21 breeds. In the micro-lymphocytotoxicity test used 75% of the sera reacted. Sixty eight of these sera were grouped into clusters according to their reaction patterns against the lymphocyte panel. Eleven of these clusters were clearly defined and were given workshop BoLA designations. In addition 22 sera were assigned to subgroups of the agreed clusters. There was no evidence that the method of production of the sera had any effect on their specificity.
Although genetic data was not available, the phenotypes of the test panel of lymphocytes are consistent with the clusters detecting antigens controlled by multiple alleles at a single autosomal locus. It was agreed to name the genetic region where this putative locus is located BoLA (bovine lymphocyte antigen).     

Ultrasound and aggressive behaviour in rats and other small mammals

Aggressive behaviour has been observed in rats, Rattus norvegicus, and fourteen other species of small mammals. Ultrasounds were detected during aggressive behaviour in at least seven of these species, and in rats two distinct types of signal were recorded. Short ultrasounds of 3 to 65 ms duration and at frequencies of about 50 kHz were produced in aggressive situations, while long pulses up to 3400 ms duration and at about 25 kHz appeared to be synchronous with the long exhalations of submissive rats. Aggressive behaviour was reduced in encounters where long pulses were emitted. The physical characteristics of the ultrasounds produced by the different species are described and the importance of these signals in the establishment and maintenance of social relationships in small mammals is discussed.     

Insect growth regulator cross-resistance studies in field- and laboratory-selected strains of the Australian sheep blowfly, Lucilia cuprina (Wiedemann) (Diptera: Calliphoridae)

Abstract Resistance to diflubenzuron in the Australian sheep blowfly, Lucilia cuprina , has rendered this insecticide incapable of preventing flystrike in sheep from a few districts in eastern Australia. Wool producers affected by this situation must find suitable alternatives to protect their flocks. Results of laboratory bioassays against one population demonstrated that, despite extremely high diflubenzuron resistance (Resistance Factor >791), it had only very low (2x) tolerance of cyromazine and dicyclanil. It is unlikely that this level of tolerance would have any practical impact on field control with either insecticide. Consequently, wool producers in districts where diflubenzuron-resistant flies are common can rotate insecticide treatment to either of these compounds to prevent flystrike in their flocks. However, unlike the highly diflubenzuron-resistant field strain, a laboratory strain selected for resistance to diflubenzuron (Resistance Factor = 617) was 10 times more resistant to dicyclanil than a susceptible strain but, like the field strain, was only two times more tolerant of cyromazine. Conversely, a field-derived strain selected in the laboratory for cyromazine resistance was 20 times more resistant to dicyclanil and 362 times more resistant to diflubenzuron than the reference susceptible strain.     

Effect of chemical ablation of myenteric neurones on intestinal cell proliferation

The duodenum or descending colon of male Wistar rats (average weight 60 g) was treated by a serosal application of a 0.2% solution of benzalkonium chloride (BAC) for 30 min. Control animals were treated with 0.9% (physiological) saline. The rats were allocated to four groups: Group DC (N = 8) in which the duodenum was treated with physiological saline; Group DB (N = 8) in which the duodenum was treated with BAC; Group CC (N = 7) in which the descending colon was treated with physiological saline and Group CB (N = 7) in which the descending colon was treated with BAC. After treatment, the animals were followed up for 5 months. At the end of the experiment, the animals were injected intraperitoneally with vincristine sulphate before sacrifice. Three segments were removed from the duodenum and descending colon for neuronal counting, catecholamine and serotonin measurements and morphokinetic studies of the epithelium. The following results were obtained: (1) there was a significant reduction in neurone number in the myenteric plexus of segments treated with BAC; (2) in the denervated intestinal segments, catecholamine levels were unchanged whereas serotonin levels were increased; (3) epithelial hyperplasia was observed in the denervated duodenum and descending colon; and (4) crypt cell production rate in the duodenum was similar in groups DC and DB but was significantly increased in the descending colon in group CB as compared with controls (CC). The present findings indicate that selective myenteric neuronal denervation caused by benzalkonium chloride plays a causative role in the hyperplasia and crypt cell production rate of the intestinal epithelium (duodenum and descending colon). These changes are probably induced by functional imbalance by the surviving neuronal elements in the gut, implicating neurotransmitters such as acetylcholine, noradrenaline, serotonin, somatostatin and vasoactive intestinal peptide.