Population Heterogeneity of Agrobacterium tumefaciens in Galls of Populus L. from a Single Nursery

This study focused on the natural crown gall infections occurring in a Leuce poplar nursery. Soil effects on crown gall frequency were detected, indicating that contamination was due to a resident Agrobacterium tumefaciens population, which was present before seedling plantation. The crown gall frequency on poplar progenies varied from 3 to 67%, indicating the feasibility of improvement in crown gall resistance. Of 129 tumor isolates, 128 were pathogenic. These isolates were of biotype 1 or 2. Biochemical, serological, and antibiotic resistance typing results concurred, indicating the presence of four biotype 1 and two biotype 2 resident subpopulations. No significant change was noticed in the relative proportions of subpopulations from one year to another. Pathogenic subpopulations both in vitro and in planta were susceptible to Kerr K84 (P. B. New and A. Kerr, J. Appl. Bacteriol. 90:172-179, 1972). In addition, no serological cross-reactions were found to occur between K84 and the pathogenic subpopulations.     

Pyridoxal 5'phosphate binding site of Escherichia coli beta cystathionase and cystathionine gamma synthase comparison of their sequences

The phosphopyridoxyl peptides of beta cystathionase and cystathionine gamma synthase of Escherichia Coli were identified after reduction, carboxymethylation and proteolysis of the holoenzymes. Their comparison with those obtained from rat liver gamma cystathionase (Fearon, C.W., Rodkey, J.A. and Abeles R.H. 1982. Biochemistry 21 3790-3794.) showed a high degree of homology between the three PLP binding sites with the presence of the tripeptide sequence: Thr-Lys(Pxy)-Tyr in their structure. This homology suggests that these enzymes of methionine metabolism have probably the same origin.     

In vivo 31P NMR in crustacean muscles: fatigue and recovery in the tail musculature from the prawn Palaemon elegans

31P NMR has been used to observe the in vivo phosphometabolite concentrations in the tail musculature from the prawn Palaemon elegans, at rest and after escape swimming and subsequent recovery. Muscular fatigue corresponds to a 60% breakdown of phosphoarginine, and a 45% increase of sugar phosphates. The pHi fell from 7.10 to 6.86. During recovery, the sugar phosphates and arginine phosphate are replenished after 20 minutes. The ATP concentration did not change throughout the experiment. The pHi was restored within 20 minutes.     

Biochemical indicators of water stress in sunflower seedlings

The free proline and chlorophyll contents, and the chlorophyllase, peroxidase and nitrate-reductase activities were determined in sunflower seedlings grown under controlled conditions and submitted to water stress induced by 14 % polyethyleneglycolj (M_r = 4000) or isotonic NaCl solution. Combined free proline content and peroxidase activity may be used for detection of the factor inducing water stress.     

Evidence for a type-IV-related collagen in Drosophila melanogaster. Evolutionary constancy of the carboxyl-terminal noncollagenous domain

Type IV collagen, a major structural component of basement membrane, has been characterized only in vertebrates. It is unique among the collagenous proteins in that it forms specific lattice networks by end-to-end interactions. In particular, in mammals the C-terminal noncollagenous domain (NCl) of collagen IV was shown to be one of the major cross-linking sites in the network assembly. Here, we give the first direct evidence of type-IV-related collagen in invertebrates by sequence analysis of cDNA and genomic DNA clones for the 3'-end of a previously characterized Drosophila collagen gene. The data describe the C-terminal 190 amino acid residues of the triple helix and the entire noncollagenous domain (231 amino acids) of the chain encoded for by this gene. Comparison with data reported for human and mouse alpha 1(IV) chains reveals that triple-helix regions are quite different, while NC1 structures are very similar. This suggests different constraints on triple-helix and NC1 domains during evolution. Present data support the assumption that the NC1 structure originated from duplication of an ancestral sequence; the extent of both interspecies and intramolecular homologies suggests the maintenance in vertebrates and invertebrates of an ancestral specific function.     

Patterns of spontaneous unit preoptic neurosecretory cell discharges in the rainbow trout, Salmo gairdneri

Extracellular antidromic potentials recorded from the neurosecretory cell body were characterized by the following criteria: constant latency, the ability to follow a high frequency rate of stimulation and the collision test. The latency of the antidromic potentials ranged from 12 to 24 ms (17.46 +/- 3.10 SD) which gave a mean conduction velocity of 0.19 m/s, typical of unmyelinated nerve fibers. Two components could be clearly distinguished in the antidromic potential. A small "A" spike which showed constant latency and a large "B" spike with a variable latency and amplitude. A delay of 6.5 ms between the two spikes could occur and sometimes the "B" spike was blocked leaving only the "A" spike. Four patterns of spontaneous activity seem to emerge: Type I (26% of units, M +/- SD = 0.77 +/- 0.32 sp/s) corresponds to a slow and irregular pattern of activity; Type II (28% of units, M = 1.58 +/- 0.47 sp/s) is hard to classify and may be related to an irregular bursting pattern of activity; Type III (28% of units, M = 2.59 +/- 1.19 sp/s) corresponds to a continuous pattern of activity; Type IV (18% of units) represents a rhythmic pattern of activity with an active phase of about 3 min (M = 2.42 +/- 0.90 min), a silent phase of about 4 min (M = 3.89 +/- 3.02 min) and a maximal frequency of unit discharge in the range 2-18 sp/s. No statistical differences exist for the mean dorsal aortic pressure (DAP) between the four types of neurosecretory cell activity.     

Intraventricular somatostatin-14, arginine vasopressin, and oxytocin: analgesic effect in a patient with intractable cancer pain

The analgesic effect of intraventricular somatostatin-14 (SOM-14), arginine vasopressin (AVP), and oxytocin (OT) were tested in one terminally ill cancer patient with a diffuse mesothelioma suffering intractable continuous and incapacitating thoracic pain. SOM-14 reduced pain by 90% for 48 min; AVP reduced pain by 95% for 75 min, and OT reduced pain by 88% for 77 min. The only notable side effects were seen after the administration of AVP, which induced anesthesia and flaccid paralysis of the lower limbs, from which the patient fully recovered after 20 h.     

Chemical structures of a galactose-rich glycoprotein of Leishmania tarentolae

1. Aqueous phenol treatment of water extracted disrupted cells of Leishmania tarentolae (LV-414) provided a glycoprotein mixture which was purified by gel filtration chromatography, and Concanavalin A-Sepharose column. 2. The bound fraction on Concanavalin A-Sepharose column (protein 74%, and carbohydrate, 26%) had [alpha]D + 9 degrees and contained mannose (18%), galactose (60%), and glucose (22%), and some of the galactose residues were resistant to periodate oxidation. 3. Treatment of the phenol extract with hot aqueous NaBH4 containing NaOH gave a preparation having mannose (12%), galactose (82%), and glucose (6%). 4. Methylation analysis showed the presence of a mainly linear structure with non-reducing end-units of mannopyranose (6%), 3-O-substituted galactopyranosyl (64%), 2-O- (11%), and 6-O- (5%) substituted mannopyranosyl, and 4-O- (9%), and 4,6-di-O- (3%) substituted glycopyranosyl units. 5. The specific rotation of the preparation, +20 degrees, indicated beta-linked galactopyranosyl units.     

Leishmaniasis in Bolivia. IV. The dog in the cycles of leishmaniasis in Bolivia

In Bolivia, the dog is involved in the cycle of visceral leishmaniasis (Leishmania (Le.) chagasi) in the Yungas (alt. 1,000-2,000 m), and also in the cycle of cutaneous leishmaniasis (Le. (V.) braziliensis) in the Alto Beni (alt. 400-600 m). But it plays a different role in the two cycles. In the Yungas focus, it is the main reservoir of Le. (Le.) chagasi and the source of contamination for man. In the Alto Beni focus, it is only a "victim-host", like man, of Le. (V.) braziliensis; the reservoir of which is unknown. Wild mammals are very likely to be involved.