Effects of Fusarium nivale and F. culmorum on the establishment of four species of pasture grass

Cocksfoot cv. Aberystwyth S 26 and timothy cv. Scots were found to be significantly more susceptible to pre-emergence death caused by Fusarium nivale and F. culmorum than were either perennial ryegrass cv. Gremie, or Italian ryegrass cv. RvP. The extent to which each grass was affected by Fusarium at the pre-emergence stage was markedly influenced by both the air temperature and the level of inoculum present in the soil at the time the seeds were sown. Under all conditions, however, cocksfoot and timothy suffered greater reductions in emergence when sown in soil containing either species of Fusarium than did the ryegrasses.
Evidence is presented which suggests that the extreme susceptibility of cocksfoot and timothy to pre-emergence damage is related to the slow germination of the former and the small seed size of the latter.
In addition to their direct effects on seedling numbers both fungi reduced the vigour of those seedlings which did emerge, cocksfoot and timothy being particularly badly affected.     

Models of parent-offspring conflict. III. Intra-brood conflict

A genetic model of parent-offspring conflict is developed for the situation where conflictors cause the parent to redirect resources from contemporaneous siblings to themselves, by increased solicitation. It is shown that there is no restriction on the spread of genes causing such conflict if there is no direct cost associated with it. We examine the effect of imposing on the conflictors a cost of the extra solicitation when the cost is felt (a) by the individual conflictor only, and (b) by all members of the brood equally. It is shown that the Evolutionarily Stable Strategies for the two situations allow a greater degree of solicitation when its cost is borne by the whole brood. Multipaternity of broods also increases the degree of conflict.     

Dynamics of the change in sensitivity of shigellae to gentamycin and cephaloridine in vitro]

The dynamics of the changes in the Shigella sensitivity to gentamicin and cephaloridin was studied in vitro using liquid nutrient media with gradually increasing concentrations of the drugs. 50 passages were performed. It was found that Shigella flexner and sonnei decreased their sensitivity to gentamicin to a little extent and remained middle sensitive. Sensitivity of Shigella flexner to cephaloridin also changed to a little extent, while Shigella sonnei became moderately resistant.     

Bacteriocin properties of Lactobacillus fermenti, Lactobacillus brevis and Lactobacillus buchneri

Four bacteriocins of L. fermenti, 3 bacteriocins of L. brevis and 1 bacteriocin of L. buchneri were studied with respect to morphology of the inhibition growth zones of the indicator strains, capacity for diffusion through cellophane, sensitivity to high temperature, bacterial proteases, trypsin, chymotrypsin, pepsin, papain, nucleases and lysozyme. According to the differences in their properties the bacteriocins were classified as belonging to 8 types, including 4 types of L. fermenti bacteriocins and 3 types of L. brevis bacteriocins.     

Molecular adaptability of carp myosin: a study of some physico-chemical properties and their comparison with those of rabbit myosin.

During thermal inactivation, the addition of as low as M urea resulted in the reduction of delta G identical to barrier of the inactivation of carp myosin Ca2+-ATPase, whereas that of rabbit myosin remained unaffected. In the absence of urea, a four-hour incubation of carp myosin was accompanied by the release of light chains at 30 degrees C, a value 10 degrees C lower than that for rabbit myosin. Electron micrographs revealed that carp myosin forms artificial thick filaments, which were uniform in size and may differ in a few details from those of rabbit. Not only that helical content of carp myosin was about 4% less than those of rabbit myosin, but it showed more sensitivity to thermal and urea denaturation; and its reversibility upon subsequent cooling or removal of urea was rather poor. The loss in helicity of myosins by urea was a concentration- and temperature-dependent biphasic reaction, with the most obvious effect observed on carp myosin. That carp myosin has increased tendency of unfolding in urea solutions was confirmed by viscosity data and the exposure of thiols also. Even in the absence of urea more SH groups of carp myosin were incorporated by DTNB, and more epsilon-amino groups reacted with NQS. Carp myosin remained in solution till the modification of about 52 surface myosin remained in solution till the modification of about 52 surface amino groups, whereas no precipitation effect was noted in case of rabbit myosin. Neither amino-acid composition nor some parameters derived from it, such as average hydrophobicity polarity index and number of polar side chains, revealed any difference pertinent to the relative stability of the two myosins. On the contrary, the contractile efficiency of carp myosin in the near physiological range was high and thus inversely related with the thermostability. This relationship along with the above evidence has been regarded to demonstrate the adaptability of carp myosin through a loose molecular conformation, which has probably been achieved by the addition of weak interactions in the course of evolution.     

Interaction between External and Internal Conditions in the Development of Photosynthetic Features in a Grass Leaf: I. REGIONAL RESPONSES ALONG A LEAF DURING AND AFTER LOW-LIGHT OR HIGH-LIGHT ACCLIMATION

Morphological and functional features were compared along a developing third leaf and fully expanded leaf from high-light- and low-light-acclimated seedlings of Lolium multiflorum.     

Trends in malpractice litigation.

Physicians who make mistakes are not necessarily negligent, contrary to prevailing opinion in the medical community. The article discusses the legal concepts of "standard of care" and "proximate cause." The incidence of favorable jury verdicts in those cases in which malpractice suits are litigated is quite high. The effects of insurance company policies in decisions about settlements on the incidence of claims is discussed and alternatives are suggested. The prevailing belief that a consent form with a patient''s signature on it is sufficient to prevent a malpractice suit is also discussed.     

The amino acid sequence of elephant (Elephas maximus) myoglobin and the phylogeny of Proboscidea

The complete amino acid sequence of skeletal myoglobin from the Asian elephant (Elephas maximus) is reported. The functional significance of variations seen when this sequence is compared with that of sperm whale myoglobin is explored in the light of the crystallographic model available for the latter molecule. The phylogenetic implications of the elephant myoglobin amino acid sequence are evaluated by using the maximum parsimony technique. A similar analysis is also presented which incorporates all of the proteins sequenced from the elephant. These results are discussed with respect to current views on proboscidean phylogeny.     

Rat kappa-chain allotypes

The presence of rat kappa-chain allotype specificities (RI-1a and b) has been studied in 13 subspecies of the seven native Australian species ofRattus. RI-la reactivity was not detected among these rats. On the other hand, extensive cross-reactivity was seen with RI-1b, some sera cross-reacting totally (R. leucopus cooktownensis), some not at all (R. colletti), and the remainder showing at least two distinct levels ofpartial cross-reactivity, confirming the existence of multiple specificities for Rl-lb. Three subspecies show polymorphism with respect to Rl-lb cross-reactivity (R. sordidus, R. colletti, andR. l. leucopus) and in one case (leucopus) breeding studies have indicated that there is allelic inheritance of this trait. The segregation of RI-1b reactivity has been studied in crosses and backcrosses made between species differing in their RI-1b reactivity, and the results are consistent with the existance of codominant alleles at a single locus. The fact that these species differ extensively in their karyotype opens the door to possible chromosomal localization of this and other genetic traits.