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Response to two-way selection for systolic blood pressure was immediate and continuous for about eight generations. In the twelfth generation, the High males differed from the Low males by 38 mmHG; the females differed by 39 mmHg. There was little overlap between the two lines and they were statistically significant from each other and from the Random control line. There appeared to be no more additive genetic variance in the eleventh and twelfth generations. Causes for the cessation of response are explored. This is probably due to a combination of natural selection acting to reduce litter sizes in the Low line, a higher incidence of sudden deaths in the High line, and loss of favorable alleles as both selection lines went through a population bottleneck in the ninth generation.—In the eleventh generation, the selected lines were used to produce F1, F2, and backcross generations. A genetic analysis yielded significant additive and dominance components in the inheritance of systolic blood pressure.

Based on multi-location tests with different edaphic and climatic conditions and process approaches to the cultivation of field crops (Oryol, Samara, Nizhny Novgorod, Voronezh), the article dwells on the algorithm of a systemic approach to studying the individual characteristics of 17 varieties and samples of winter wheat, and shows the principles of their selection to form a single system for the purpose of stabilising the production of high-quality grain. Ecological approaches to the assessment of individual characteristics of different wheat varieties allowed identifying bottleneck issues related to the implementation of their adaptive potential, behaviour in the single system of agrobiogeocenosis, specifying the influence of the genotype–environment interaction on the manifestation of individual characteristics. The understanding of these issues makes it possible to develop a process sequence beneficial for the formation of genotypes with high productivity. Following the analysis, the breeds Leonida, Grom and Nemchinovskaya 85 wheat varieties were identified as promising for production in Central Russia. They showed high productivity and proved to be close in terms of sensitivity to growing conditions. In addition, a new wheat variety, Nemchinovskaya 85, demonstrated high quality of grain product. Izumrud Dubovitskogo and DF2020 varieties were distinguished by a high level of adaptive properties, expressed as their superiority in severe conditions of the Volga region and regions with a low level of soil moisture during grain filling. The study also suggests high processability and narrow limits of ecosystem boundaries when using Stork and Sineva wheat varieties in production, which most fully implemented their potential only in the system of intensive cultivation technologies with moderate to increased soil-moisture regimen in the second half of the vegetation season.

Since sugarcane plants in Hawaii translocate sucrose at the rate of over one million tons per year, translocation studies have an immense economic potential. Studies with the infrared analyzer indicate that the accumulation of sucrose in leaves during the day may inhibit photosynthesis (unpublished data), so that translocation may form a bottleneck in production. Of more importance to the general plant physiologist, sugarcane studies may contribute to the theory of translocation. In 1947 investigations on translocation of C14 were begun at the Experiment Station of the Hawaiian Sugar Planters' Association (7, 12, 27), and the results of the ensuing 15 years of research are summarized here. The sugarcane plant possesses many advantages for studying translocation. The long symmetrical blade, with parallel venation and with no lobes or dissections, can be readily cut into uniform parts for studying velocities of movement. The large size of the plant makes it possible to take samples from uniform tissues for several types of analysis. Samples can be taken at specific positions because of the regular subdivision of the stalk into nodes and internodes. Thus, sugarcane is well constructed for determination of components moved and of rates and direction of movement. Sugarcane has a disadvantage for translocation tests because it is a monocotyledon with typical monocotyledonous structure of the stem. It is therefore difficult to separate xylem and phloem for studying tissues involved in transport; moreover, on sugarcane there is no stem-infesting aphis which could be used for sampling the phloem. Studies of translocation of radioactive photosynthate have been summarized recently (17, 48, 57). Even so, Crafts (17) has called attention to the need for collecting more data on this important subject. Translocation in sugarcane was studied by Hartt (23) who analyzed the sugars in sheaths during the day and the night and concluded that a temporary storage of polysaccharides in the sheath during the night facilitated trianslocation. Burr et al. (8) reviewed studies of translocation of C14 in sugarcane through October 1956, and also presented evidence of a circulatory system in the sugarcane plant (9). Yang (55) reported on studies in Taiwan on translocation of C14 in sugarcane. Brief presentations of some of the results reported herein are in press (24, 27). This paper describes the normal course of translocation in plants grown with adequate fertilization. Effects of varying climatic conditions, deficiencies of N, P, or K, and other factors will be presented in subsequent papers.

1. In the hypodermis and gill of the Crustacea fructose 1,6-diphosphatase (EC 3.1.3.11) functions at a primary branch point between glycogen and chitin synthesis. In these tissues of the Arctic king-crab, Paralithodes camtchatica, fructose diphosphatase occurs in two electrophoretically distinguishable forms. 2. Fructose diphosphatase I (pI7.2-7.5) accounts for 70 and 10% of total fructose diphosphatase activity in the hypodermis and gill respectively, whereas fructose diphosphatase II (pI5.3) accounts for 30 and 90% of the total activity in the two tissues. Both forms display a neutral pH optimum, have an absolute requirement for a bivalent cation, and are potently inhibited by high concentrations of AMP and substrate. 3. Fructose 1,6-diphosphate saturation follows Michaelis-Menten kinetics for both fructose diphosphatases; the K(m) (fructose diphosphate) for fructose diphosphatase I is somewhat higher than for fructose diphosphatase II. In the presence of 50-200mm-K(+), the K(m) (fructose diphosphate) increases and at high concentrations of K(+) fructose diphosphate saturation follows sigmoidal kinetics. 4. UDP-N-acetylglucosamine and UDP-glucose at high concentrations specifically and potently inhibit fructose diphosphatase II, but do not significantly affect fructose diphosphatase I activity. 5. Low concentrations of UDP-N-acetylglucosamine activate fructose diphosphatase II by a decrease in the apparent K(m) (fructose diphosphate), but fructose diphosphatase I is again refractory to UDP-N-acetylglucosamine under these conditions. 6. In the presence of K(+) and UDP-N-acetylglucosamine, fructose diphosphatase II is able to compete for limiting fructose diphosphate about three times more effectively than is fructose diphosphatase I. 7. AMP inhibition of both forms of the enzyme is subject to three independent variables: (a) alkaline pH increases the K(i) (AMP), (b) K(+) decreases the K(i), increases the sigmoidicity of inhibition kinetics, increases the maximum inhibition attained, and abolishes the effect of pH on AMP inhibition, and (c) Mg(2+) strongly de-inhibits AMP-inhibited fructose diphosphatase. 8. It is postulated that the presence of two forms of fructose diphosphatase aids controlled channelling of carbon through the fructose diphosphatase ;bottleneck' either towards glycogen synthesis or chitin synthesis, but not towards both simultaneously.

SUMMARYPrevious studies have shown that reciprocal recurrent selection (RRS) would be ineffective in the early cycles of selection if over-dominant loci were at equilibrium gene frequencies in both selected populations. It is shown in the present study that response to RRS may be reduced by this unstable equilibrium even when gene frequencies are as much as 30 % removed from the theoretical equilibrium frequency. Reducing one population to a bottleneck of two individuals for one generation or more before initiating RRS (RRSB) was very effective in overcoming the unstable equilibrium. RRS with recurrent inbreeding, then outcrossing in both populations each cycle of selection (RRSC) was not effective in overcoming the unstable equilibrium, but yielded greater response per cycle after selection response began. The effectiveness of RRSC was inversely proportional to the heritability of the trait. Use of these modifications to increase the effectiveness of RRS in poultry breeding is discussed.

Autumn grown potatoes harvested in December cannot be used for planting in February–March, as they are still dormant at that time. The lengthy dormant period ofUp-to-Date, the main variety cultivated in Israel, was found to be the bottleneck of the problem of supply of locally grown seed tubers. In order to find varieties with a shorter dormant period, 52 varieties from different sources were introduced. The seed material was propagated twice before it was used for the first screening test in spring 1956. The first test has shown that varieties with a short dormant period gave the best results and those with a long one the worst. The second screening in spring 1957, in which a limited number of the most promising varieties were tested, has shown that length of growing period is at least as important as length of dormant period, and that early and medium-early varieties are best. In spite of the results obtained we consider that it will be necessary to breed new varieties more adapted to the specific requirements of growing two crops a year.

Sternbergia fischeriana, a spring flowering bulbous annual, is the only species of the genus cultivated in Kashmir. Somatic complement of this species consists of 4 submedian and 18 subterminal chromosomes. The karyotype resembles that of S. lutea, an autumn flowering species worked out by Battaglia (1949).Though the species is heterozygous for three interchanges and a paracentric inversion, it has not as yet developed a balanced lethal system to maintain this heterozygosity. Vegetative reproduction, however, comes to its rescue and enables it not only to overcome the bottleneck of total sterility but also to conserve hybridity.

SUMMARYThe response to selection in any line depends on the size of the initial sample by which the line is founded. For a single locus with additive gene action the effects of number of founders on early rate of response and on final limits are studied in relation to selection intensity and number of parents in the selected line. The reduction in total response caused by a small number of founders is greatest for large populations under intense selection, especially when the desirable alleles are rare in the base population. If these alleles are at high frequencies it is possible that a line which has gone through a bottleneck may be more sensitive to a reduced population size during subsequent selection than a line which has not. Under some conditions replicate selection lines founded with small samples are likely to be less variable in response than lines founded with moderately large samples.

The references concerning acoustic tumor are divided into two groups composed of statical and analytical studies.From the latter standpoint, the cases with acoustic tumor experienced in the past five years were investigated and an attempt to establish the basis was made for a more complete clinical study of aco-ustic tumor which are to follow in the succeeding papers.The subjects are 25 cases with unilateral acous-tic tumor which came to the department of otolar yngology, Kyushu University, from 1958 to 1962 and were verified by operation.1. The appearance of initial symptom averaged two years and two months before admission, and the age incidence of 39 years was nearly in accord with the literature. Female subjects were predo-minant for the present series (1: 1.6).2. 80 per cent of initial symptoms and chief complaints were the symptoms of the eighth nerve. Of those, furthermore, complaint of cochlear symp-toms were much more frequent than vestibular symptoms and this tendency increased with the initial symptom.With regard to the character of vestibular symptom, the term vertigo was used to designate "hallucination concerning position or movement, either in the individual himself or in external objects, that involves a defect in the equilibrium of the body" in a narrow sense. From the patient's complaint of vestibular disturbances, however, it was difficult to differentiate peripheral labyrinthine lesion from acoustic tumor especially in the initial stages.3. In 7 cases the deafness was total and in 8 cases it was moderate. In the remaining 9 cases except in a case unexamined there were islet hear- ing losses.There is no similarity of pattern to be found among these pure-tone audiograms.The discrimination loss for speech was almost parallel to the hearing loss for pure tones except a case of the examined 9 cases.All of the cases with hearing loss for speech on the side opposite the tumor differed from the cases with contralateral pure-tone loss and showed evidence of increased intracranial pressure.It is, therefore, inferred that the auditory disturbance arising from increased intracranial pressure manifested the marked reduction of discrimi-nation when compared with pure-tone audiogram bottleneck principle (Jerger, 1960)-and that this was a diagnostic characteristic.

Triploid A. cepa var. viviparum has been earlier described as a genomic allotriploid with the genomic formula AAB. Studies conducted on the mode of chromosome pairing and used in conjecture with the nature of karyotype, however, favour segmental allotriploid status for the taxon with the genomic formula A A' A''. A. fistulosum and A. cepa are regarded as the progenitors of ‘Pran’ (3X A. cepa var. viviparum). The unreduced pollen grains of the F1 hybrid through backcrossing seem to have resulted in the formation of the triploid cultivar. Like many other polyploids, the latter has taken to vegetative mechanism of propagation to overcome the bottleneck of sterility.

1. 1. In the gill of the king crab, Paralithodes camtchatica , the activity of the pentose shunt is high relative to glycolysis, C-6/C-1 ratios (in CO 2 ) are about 1/100 and drop to nearly 1/1000 on addition of NADP. 2. 2. The shunt is inhibited by Na + , inorganic phosphate, Ca 2+ , Mg 2+ , citrate and high concentrations of ATP; it is activated by low concentrations of ATP and NADP. 3. 3. Glycolysis is only slightly affected by iodoacetate because phosphofructokinase acts as a bottleneck earlier in the pathway, keeping glycolytic rates low. 4. 4. The Krebs cycle, which accounts for about 90 per cent of total respiration, is activated by ADP, inorganic phosphate and Na + ; it is inhibited by high concentrations of K + , citrate and ATP.

Extracts of the plant pathogenic organism Xanthomonas phaseoli contain both TPN- and DPN-linked glucose-6-phosphate dehydrogenases as well as a DPN-specific glyceraldehyde phosphate dehydrogenase. DPNH oxidase is very active and sensitive to high concentrations of cyanide. No evidence could be found for the presence of pyridine nucleotide transhydrogenase.Ribose-5-phosphate is metabolized via the pentose cycle; sedoheptulose phosphate is an intermediate and other criteria of the functioning of the pentose cycle are met when ribose-5-phosphate is the substrate. The same system also functions with 6-phosphogluconate as substrate but at a level which suggests that this pathway is not of great significance.The Entner–Doudoroff 6-phosphogluconate-splitting pathway is the major avenue of hexosephosphate utilization in cell-free extracts. Pyruvate formation and utilization are discussed in relation to function and cofactor requirements.While phosphoglucose isomerase, aldolase, triosephosphate isomerase, and the enzymes converting phosphoglyceraldehyde to pyruvate are present and enzymatically active, phosphofructokinase appears to be the "bottleneck" to glycolysis. On the other hand fructose-1,6-diphosphate is oxidized by both DPN- and TPN-linked pathways, the latter through the efficient functioning of a specific phosphatase which forms fructose-6-phosphate readily. Glycolysis is considered to play only a very minor role in these extracts.A new "hexose cycle" for the metabolism of hexosephosphate is proposed. It consists of oxidation through "Zwischenferment", followed by the Entner–Doudoroff splitting system and resynthesis of hexosemonophosphate through reversal of the aldolase reaction followed by specific carbon-1 phosphate hydrolysis of fructose-1,6-diphosphate. The cycle is shown to be metabolically feasible and thermodynamically likely. It is considered to be the pathway by which cells which tend not to utilize the pentose cycle or classical glycolysis, but have an active 6-phosphogluconate-splitting system, metabolize hexosephosphate. Pyruvate produced as a result of the operation of this system is then oxidized via the tricarboxylic acid cycle in glucose-grown cells.

Publisher Summary The microbial flora of the rumen can synthesize all the protein amino acids. The weak labeling of some amino acids shows that their synthesis may form a bottleneck in protein synthesis. Thus, it seemed possible to develop in the rumen by adaptation a microbial flora that could synthesize essential amino acids and microbial protein from ammonia more effectively than the rumen microorganisms of cows on normal feeding. For the maintenance of a cow or for rearing, a heifer about 300 g of digestible crude protein per day is needed, whereas for each kilogram of milk produced, the feed must contain roughly 60 g of digestible crude protein. A cow producing 15 kg of milk per day has, thus, to receive about 1,200 g of digestible crude protein. Many problems regarding the adaptation of the microbial flora of the rumen to the most effective synthesis of protein from ammonium nitrogen, the biosynthesis of different milk components, and generally the capacity for synthesis of the mammary gland actually require the study of milk production on a purified feed, with urea and ammonium salts as the sole source of nitrogen.

The preceding paper has demonstrated that cell processes in white matter, including axons, are extremely susceptible to the damaging effects of cyanide (1). Axons are, after all, extensions of neuronal cytoplasm. It is well known that neurons are highly susceptible to anoxia. Therefore, the electron microscopic observations suggest a close analogy between histotoxic anoxia (cyanide) and other forms of anoxia. If this is valid, why does cyanide often attack white matter selectively? Most authors agree that the mechanism of histotoxic anoxia involves poisoning of the cytochrome oxidase system. This enzyme is particularly low in the white matter. Presumably, it constitutes a bottleneck for oxidative metabolism in white matter. According to this mechanism, cyanide should damage all white matter indiscriminately, inasmuch as regional differences in cytochrome oxidase content of white matter have not been reported. But this is not the case. There is a hierarchy of sensitivity to cyanide among white matter structures. The corpus callosum, other commissures, and the white matter of the corpus striatum are susceptible in varying degrees, while other fiber tracts escape. Even the susceptible structures cited are not affected in entirety. The present investigation is directed toward an explanation of the exact topographic distribution of cyanide lesions in the corpus callosum. The investigation was made possible by development of the hydrogen cyanide technic, inasmuch as no other method can produce lesions in many animals of exactly the same duration, in exactly the same structure, of any desired degree of severity. Our results give no reason to doubt present theories of cyanide action, but suggest that additional factors, specifically, blood supply, determine the details of lesion distribution.