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Summary: Using specific substrates and inhibitors, the presence of acetylcholinesterase (AChE), carboxylesterase (B-esterase) and arylesterase (A-esterase) has been histochemically studied in the developing mouse retina. In the neural retina the perikarya of the Mller cells, ganglion cells and horizontal cells showed high B-esterase activity at the initial stages of their development. In the Mller cells, a second peak of B-esterase activity, coinciding with the time of formation of their lateral processes, was found. AChE first appeared in the ganglion cells at birth and increased thereafter. With the progress of synaptic development, AChE activity in the ganglion cell perikarya was reduced while the enzyme rapidly accumulated in the inner plexiform layer. AChE was also localized in the horizontal cells at the initial stage of their development and completely disappeared thereafter. AChE activity was localized in the outer plexiform layer at the time of weaning. A-esterase was detected in the ganglion cells only and appeared to be lysosomal.In the pigment epithelium only B-esterase was present. The enzyme first appeared in the late prenatal period and rapidly increased after birth.

4-Amino-4-carboxylthiapyran crystallizes in space groupP21/c witha = 10.61,b = 6.55,c= 10.97 Å, ß =96.3 °, andZ = 4. The structure was solved by the heavy-atom method, with 897 observed reflections, and refined to anR of 0.093. The packing of the structure is found to be very similar to that in the structure of 1-aminocyclohexane carboxylic acid. The conformation of the thiapyran ring exists in the “puckered chair” form.

4-Amino-4-carboxylthiapyran hydrobromide crystallizes in the monoclinic space groupP21/m, witha= 9.72 Å,b= 6.60 Å andc=7.10 Å,ß = 94.8 ° andZ= 2. The structure was solved by the heavy atom method with 786 observed reflections and refined to anR of 0.076. There is an interesting weak interaction which the hetero sulfur atom of the thiapyran ring makes with a symmetry related amino nitrogen (N...S distance 3.34 Å) which significantly affects the “puckered-chair” conformation of the thiapyran ring.

Abstract: Citrate synthase activity ofSaccharomyces cerevisiae was determined by a radioactive assay procedure and the reaction product,14C-citric acid, was identified by chromatographic techniques. ATP, d-ATP, GTP and NADPH were most inhibitory to the citrate synthasein vitro. The activity was inhibited to a lesser extent by ADP, UTP, and NADP whereas, AMP and CTP were much less inhibitory. NADH, like NAD, glutamic acid, glutamine, arginine, ornithine, proline, aspartic acid and α-ketoglutarate exhibited no inhibition. These results have been discussed in the light of the role of citrate synthase for the energy metabolism and glutamic acid biosynthesis.

Four chemical agents, EMSEMS: Ethyl methanesulfonate; MNNG: N-methyl-N\t'-nitro-N\t'-nitrosoguanidine; NA: Nitrous acid; ICR-170: 2-methoxy-6-chloro-9-[3-(ethyl-2-chloroethyl) aminopropylamino] acridine 2 HCl; UV: Ultra violet radiation., MNNG, NA, ICR-170, as well as UV were used to induce mutations in the wild-type haploid strain X2180-1B (a) of Saccharomyces. A total of 2053 (EMS, 427; MNNG, 444; NA, 469; ICR-170, 456; UV, 257) lysine-requiring mutant clones were isolated from many independent treatments and by nystatin enrichment technique. Mutants were classified into various functional groups on the basis of complementation analysis with 14 tester strains (lys 1 to lys 15 except lys 3). Of the clones analyzed, the number of isolates unable to complement with a given tester strain ranged from 2 for lys 5 to 918 for lys 4. Three of the mutually complementing lysine loci (lys 1, lys 2, and lys 4) accounted together for over 85% of the mutant clones whereas lys 6, lys 7, lys 8, and lys 14 had less than 10 noncomplementing isolates each. Mutants for lys 4 were most frequent with all of the mutagens tested except with NA in which case the mutants for lys 2 were most frequent. A total of 56 isolates failed to complement with lys 10, lys 11, and lys 12. Similarly, 47 isolates failed to complement with lys 9 and lys 13 simultaneously. Only 44 isolates complemented with all of the tester strains used.

The near ultraviolet and visible light (VL) impinging at an intensity of 2–5 × 10(2) J s-1 m-2 for 2–5 h kills the mitotic and the early S-phase (0- to 15-min-old) amoebae. At the mid- and late S-period only a fraction of cells are killed by VL and G2 phase cells are quite resistant. Amoebae of all cell cycle stages show a delay in the first mitotic division. DNA synthesis, as measured by [3H]thymidine incorporation, is depressed in the VL-exposed early-S amoebae. A concurrent but temporary inhibition in [3H]leucine incorporation also occurs in these cells. However, no significant change in [3H]uridine incorporation has been found. To localize the site of lethal damage, nuclear transplantation studies were undertaken between the control amoebae and the amoebae treated with VL. The nucleus of a VL-exposed early S-phase cell recovers when transplanted immediately after VL exposure into an enucleate G2 cytoplasm but dies if grafted into an enucleat S-phase cytoplasm. The therapeutic effect of the G2 cytoplasm, although at a lower level, is also evident even when the treated early S-phase nucleus is implanted 20 h later, but not after 48 h, into the G2 cytoplasm. The amoeba cytoplasm shows resistance to VL-irradiation, can accept a control nucleus from any cell cycle stage, and function normally. The G2 nucleus also remains apparently unaffected to VL exposure and can survive when it is transfered to the control cytoplasm of any cell-cycle phase. All these findings are discussed in the light of the possible existence of a repair system against VL-induced damage in the G2-phase amoeba.

Relationship of citrate synthase (EC 4.1.3.7) to the biosynthesis of glutamic acid was investigated by characterizing a new glutamic acid auxotroph FL100-D1 (glu 3) of Saccharomyces cerevisiae. Nutritional requirement of the mutant was satisfied by L-glutamic acid, L-glutamic acid peptide as well as several analogs of glutamic acid, but not by proline, ornithine, arginine, lysine or aspartic acid. The mutant was unable to utilize nonfermentable carbon sources, glycerol, acetate or lactate. Mutant glu 3 unlike aconitaseless glutamic acid auxotroph glu 1, failed to accumulate 14C-citric acid in vivo from 1-14C-sodium acetate or U-14C-glutamic acid. Both spectrophotometric and radioactive assay procedures demonstrated a lack of significant citrate synthase activity in the dialysed extract of the mutant compared to the wild type strain. Mutant glu 3 complemented with glu 1 and glu 2 individually in vivo and exhibited a significant aconitase (EC 4.2.1.3) activity in vitro.

Regeneration time of the hypostome increases progressively from the oral to the aboral direction. Converse is true for the basal disc. More time is required to form basal disc from aboral-oral direction.In absence of both terminal determinants, the time of regeneration of hypostome and basal disc in a longer piece is less than that of a smaller middle piece; regeneration time in the smaller fragment takes more time.Inhibitory effect of hypostome on the formation of a basal disc has been evidenced in which a slight faster rate of basal disc regeneration is possible in absence of the hypostome in the full length of hydra.In smaller pieces, slower rate of hypostome regeneration is noted in absence of basal disc at posterior regions of the oral end.Hypostome lengthens the time of formation of basal disc in its vicinity, whereas basal disc accelerates the formation of a hypostome in its nearby. Hypostome determining influence is stronger than its counterpart and can act from a greater distance.Determination on hydra has been explained on the basis of an interaction between the relative developmental potential of the participating cells at a given level and the strength of the diffusible communicating system originating from the regions of physiologically active area of hypostome.

Application of 100 pounds N per acre gave optimum yield of rice, provided plants did not lodge before heading. Pre‐heading lodging reduced level of nitrogen consumption and response and the yield. Lodging seemed to be a physiological phenomenon rather than a varietal character. It originated from structural weakness development in culm tissues and was caused primarily by deeper submergence of plants during vegetative growth aided by high nitrogen concentration in soil.

Several mannans from yeasts give proton magnetic resonance spectra with distinctive H-1 signals at higher field than τ 4.55. A number of these mannans were investigated polarimetrically and each has a specific rotation corresponding to a mixture of α- and β-D-linkages. Four were partially hydrolyzed and shown to have most of the α-linkages in the main chains and the β-linkages in the side chains. Detailed structural investigations showed that the Pichiapastorismannan probably has an α-(1→6)-D-manno-pyranosyl main-chain substituted in the 2-positions with a substantial proportion of O-α-D-mannopy-ranosyl-(1→2)-O-β-D-mannopyranosyl-(1→2)-O-β-D-mannopyranosyl-(1→2)-O-α-mannopyranosyl side-chains (1). The related mannan from Citeromycesmatritensishas a similar main-chain, which is substituted in the 2-positions by α-D-mannopyranosyl units and β-(1→2)-pyranose-linked D-mannotriosyl and perhaps mannobiosyl side-chains (2).

Some di-O- and tri-O-methylmannoses which are unknown or difficult to prepare have been synthesized. These and the other isomers, which can arise from methylation–fragmentation analyses of mannofuranose- and mannopyranose-containing polysaccharides can be used as gas–liquid chromatographic (g.l.c.) standards. A system has been devised in which methylation fragments are fractionated on a cellulose column into di-O-, tri-O-, and tetra-O-methylmannose fractions, which are then analyzed individually by g.l.c. following conversion to suitable derivatives.

The reduction of hexofuranose and hexopyranose acetals with LiAlH4–AlCl3(1:1, probably AlH2Cl) to the corresponding ethers proceeds in similar fashion as that of simple acetals and ketals (Scheme I) (refs. 1–7). Certain O-methyl and O-benzyl derivatives, not readily obtainable otherwise, are conveniently synthesized from appropriate acetals in this way. Cyclic orthoesters of glucofuranose may be selectively reduced to acetals; the steric course of such reduction has been shown unequivocally in the case of orthoformates (Scheme II). Of several cleavable groups, the ease of hydrogenolysis is (a) cyclic orthoester > isopropylidene ketal, cyclohexylidene ketal > benzylidene acetal > ethylidene acetal > formal and (b) 5,6-O-linked or 3,5-O-linked acetal or ketal > 1,2-O-linked acetal or ketal.

Abstract: Malwa plateau is composed mainly of basalt traps. The basalt flows are of uniform character and the total thickness varies from 50 m to 135 m. A number of flows have been identified, indicating breaks in the continuity of the eruptions. The breaks were of shorter nature as evidenced by the presence of thin discontinuous bands of intertrappean sediments. The trap maintains a uniform horizontal attitude with well developed joints and is sometimes scoriaceous. Petrographically, these basalts are divisible into porphyritic, massive and vesicular types. The rock types are composed essentially of plagioclase, pyroxene, iron ore and glass. Stray occurrences of olivine have been noted from the lower section of the flows. The plagioclase ranges in composition between An 59 and An 68 and the pyroxene is diopsidic augite. The rocks are fine grained, aphanitic showing porphyritic, glomeroporphyritic, intergranular, micro-ophitic and flow textures. It is concluded that the lava flowed out quietly, in some cases through fissures, and that the area is away from the main centres of differentiation.

AbstractA study of the geological history of a small dioritic mass near Gairloch has revealed the presence of rock types and structural elements not represented in most of the Lewisian of the district. Coarse grained diorite, showing intrusive relations to granulitic rocks of possible sedimentary derivation, has been foliated and subsequently intruded by microdiorite during pre-Laxfordian episodes. The Little Sand mass has subsequently been involved, probably as a thrust slice of basement, in the sequence of Laxfordian (about 1,500 m.y.) structural and metamorphic episodes which affected the more common Lewisian metasediments and metabasites.

A study is made of the effects of density-of-states tails associated with the subsidiary minima (L) of the conduction band on the ionized-impurity scattering of electrons in the degenerate principal minimum (Γ). Wo investigate the changes of mobility and lifetime of theΓ-electrons with uniaxial compression along the <111>, <110> and <100> directions. The Thomas-Fermi screening parameter is calculated in aself-consistentmanner. When the electron concentration is such that the Fermi level lies below theL-minima in the unperturbed band picture, the tailing of the density of states leads to a monotonic increase in screening and a resulting increase in electron mobility and lifetime with uniaxial compression. This result is consistent with the observed stress-induced changes of the Hall mobility and the Shubnikov-de Haas amplitude in Te-doped GaSb at 4.2 °K as reported by Sherwood and Becker. Si è effettuato uno studio degli effetti delle code della densità degli stati associate con i minimi sussidiari (L) della banda di conduzione sullo scattering degli elettroni sulle impurità ionizzate nel minimo principale degenere (Γ). Si studiano i canibiamenti della mobilità e della vita media degli elettroniΓa seguito di compressione uniassiale lungo le direzioni <111>, <110> e <100>. Si calcola in modo autoconsistente il parametro di schermatura di Thomas-Fermi. Quando la concentrazione elettronica è tale che il livello di Fermi sta al di sotto dei minimiLnel quadro della banda imperturbata, la coda della densità degli stati porta ad un incremento monotono nella schermatura e ad un risultante incremento nella mobilità e vita media degli elettroni a seguito di compressione uniassiale. Questo risultato è consistente con i cambiamenti osservati nella mobilità di Hall e nell’ampiezza di Shubnikov-de Haas indotti dallo sforzo nel GaSb drogato con Te a 4.2 °K, riportati da Sherwood e Becker. Исследуется влияние хвостов плотности состояний, связанных с вторичными минимум ами (L) зоны проводимост и, при рассеянии элект ронов на ионизо проводимости, при рас сеянии электронов на ионизованных примес ях в вырожденном глав ном минимуме (Г). Мы исс ледуем изменения под вижности и времен ионизованных примес ях в вырожденном глав ном минимуме (Г). Мы исс ледуем изменения под вижности и времени жи зни Г-электронов при н еаксиальном сжатии в доль направлений <111>, <110> и <100>. Самосогласованным образ (Г). Мы исследуем измене ния подвижности и вре мени жизни Г-электрон ов при неаксиальном с жатии вдоль направле ний <111>, <110> и <100>. Самосогласов анным образом вычисл яется параметр экран ирования Томаса-Ферм и. Когда концентрация электронов является такой, что урове Г-электронов при неак сиальном сжатии вдол ь направлений <111>, <110> и <100>. Са мосогласованным обр азом вычисляется пар аметр экранирования Томаса-Ферми. Когда ко нцентрация электрон ов является такой, что уровень Ферми лежит н иже L-минимумов в невоз мущенной зонной карт ине, то хвост плотност и состояний приво направлений <111>, <110> и <100>. Само согласованным образ ом вычисляется парам етр экранирования То маса-Ферми. Когда конц ентрация электронов является такой, что ур овень Ферми лежит ниж е L-минимумов в невозму щенной зонной картин е, то хвост плотности с остояний приводит к м онотонному увеличен ию экранирования и ре зультирующему увели чению подвижности и в рем вычисляется парамет р экранирования Тома са-Ферми. Когда концен трация электронов яв ляется такой, что уров ень Ферми лежит ниже L-м инимумов в невозмуще нной зонной картине, т о хвост плотности сос тояний приводит к мон отонному увеличению экранирования и резу льтирующему увеличе нию подвижности и вре мени жизни при неакси альном сжатии. Этот ре зультат согласуется с наблюденными измен ениями, индуцир Когда концентрация э лектронов является т акой, что уровень Ферм и лежит ниже L-минимумо в в невозмущенной зон ной картине, то хвост п лотности состояний п риводит к монотонном у увеличению экранир ования и результирую щему увеличению подв ижности и времени жиз ни при неаксиальном с жатии. Этот результат согласуется с наблюд енными изменениями, и ндуцированными напр яжением, подвижности Холла и амплитуды Шуб никова-де Гааза в GaSb с пр исадкой Те при 4.2 °К, кот уровень Ферми лежит н иже L-минимумов в невоз мущенной зонной карт ине, то хвост плотност и состояний приводит к монотонному увелич ению экранирования и результирующему уве личению подвижности и времени жизни при не аксиальном сжатии. Эт от результат согласу ется с наблюденными и зменениями, индуциро ванными напряжением, подвижности Холла и а мплитуды Шубникова-д е Гааза в GaSb с присадкой Те при 4.2 °К, которые был и получены Шервудом и Беккером. зонной картине, то хво ст плотности состоян ий приводит к монотон ному увеличению экра нирования и результи рующему увеличению п одвижности и времени жизни при неаксиальн ом сжатии. Этот резуль тат согласуется с наб люденными изменения ми, индуцированными н апряжением, подвижно сти Холла и амплитуды Шубникова-де Гааза в GaSb с присадкой Те при 4.2 °К, которые были получен ы Шервудом и Беккером. к монотонному увелич ению экранирования и результирующему уве личению подвижности и времени жизни при не аксиальном сжатии. Эт от результат согласу ется с наблюденными и зменениями, индуциро ванными напряжением, подвижности Холла и а мплитуды Шубникова-д е Гааза в GaSb с присадкой Те при 4.2 °К, которые был и получены Шервудом и Беккером. результирующему уве личению подвижности и времени жизни при не аксиальном сжатии. Эт от результат согласу ется с наблюденными и зменениями, индуциро ванными напряжением, подвижности Холла и а мплитуды Шубникова-д е Гааза в GaSb с присадкой Те при 4.2 °К, которые был и получены Шервудом и Беккером. жизни при неаксиальн ом сжатии. Этот резуль тат согласуется с наб люденными изменения ми, индуцированными н апряжением, подвижно сти Холла и амплитуды Шубникова-де Гааза в GaSb с присадкой Те при 4.2 °К, которые были получен ы Шервудом и Беккером. согласуется с наблюд енными изменениями, и ндуцированными напр яжением, подвижности Холла и амплитуды Шуб никова-де Гааза в GaSb с пр исадкой Те при 4.2 °К, кот орые были получены Ше рвудом и Беккером. индуцированными нап ряжением, подвижност и Холла и амплитуды Шу бникова-де Гааза в GaSb с п рисадкой Те при 4.2 °К, ко торые были получены Ш ервудом и Беккером. амплитуды Шубникова-де Гааза в GaSb с присадко й Те при 4.2 °К, которые бы ли получены Шервудом и Беккером. °К, которые были получ ены Шервудом и Беккер ом.

Carbon-13 Fourier transform n.m.r. spectra of the biopolymer, heparin, are described. The proton-decoupled spectrum corresponds to that of a molecular structure based on 12 carbon atoms, and the observed chemical shifts are shown to be consistent with a previously-proposed alternating sequence consisting of (1 → 4) linked residues of α-D-idopyranosyluronic acid 2-sulfate and 2-deoxy-2-sulfamino-α-D-glucopyranosyl 6-sulfate. Line-broadening of the C-6 signal of the latter residue indicates that spin–spin relaxation of the 13C nucleus of this sulfated primary carbinol group is more effective than for the 13C nuclei of the sugar rings. Among model compounds utilized for assignment of the signals from heparin is a disaccharide, 4-O-(α-L-idopyranosyluronic acid 2-sulfate)-2,5-anhydro-D-mannose 6-sulfate, prepared in 65% yield by deaminative degradation of heparin.

1.Regeneration time of the hypostome increases progressively from the oral to the aboral direction. Converse is true for the basal disc. More time is required to form basal disc from aboral-oral direction.2.In absence of both terminal determinants, the time of regeneration of hypostome and basal disc in a longer piece is less than that of a smaller middle piece; regeneration time in the smaller fragment takes more time.3.Inhibitory effect of hypostome on the formation of a basal disc has been evidenced in which a slight faster rate of basal disc regeneration is possible in absence of the hypostome in the full length of hydra.4.In smaller pieces, slower rate of hypostome regeneration is noted in absence of basal disc at posterior regions of the oral end.5.Hypostome lengthens the time of formation of basal disc in its vicinity, whereas basal disc accelerates the formation of a hypostome in its nearby. Hypostome determining influence is stronger than its counterpart and can act from a greater distance.6.Determination on hydra has been explained on the basis of an interaction between the relative developmental potential of the participating cells at a given level and the strength of the diffusible communicating system originating from the regions of physiologically active area of hypostome.

Thymine starvation of E. coli B/r resulted in a decrease in single-strand molecular weight of DNA, as determined by sedimentation in alkaline sucrose gradient. This decrease could not be compensated by 60 min incubation in growth medium after thymine starvation. The strand breaks in DNA induced by x-irradiation could not be repaired in growth medium in 60 min when the cells were prestarved of thymine. Thymine-starved cells also showed more strand breaks in DNA, at the same levels of survival, due to x-irradiation than the cells that were not so starved.

A description with drawings and photomicrographs is given of a new variety ofThielavia sepedonium Emmons named var.minor which differed from the species (six strains studied) in having much smaller cleistothecia under a large variety of nutritional conditions.

The reduction of α-aminoadipate to α-aminoadipic δ-semialdehyde by a cell-free extract of Saccharomyces is shown to be a three-step process. First the amino acid reacts with ATP to form an adenylyl derivative. Then the adenylyl derivative of α-aminoadipate is reduced in the presence of NADPH. In the third step the reduced adenylyl derivative of the amino acid is cleaved to form α-aminoadipic δ-semialdehyde. The presence of Mg2+is necessary for the first and second steps. The third step does not need any cofactors. The product of the first step was isolated by chromatography after incubating the cell-free extract of Saccharomyces with α-aminoadipate, ATP and Mg2+. The isolated product was identified as an adenylyl derivative of α-aminoadipate and could be converted into α-aminoadipic δ-semialdehyde under the stated experimental conditions. The product of the second step was too unstable to be identified.

Genetic lesions of 10 of the lysine loci in Saccharomyces have been provisionally correlated with the various enzymatic steps of the homocitric acid pathway for the biosynthesis of lysine. The characterization of mutational blocks in different mutants was made on the basis of the accumulation of appropriate intermediates, lack of enzymatic activity, and feeding experiments. Genetic lesions in mutants lys4, lys7, lys8, and lys12 correspond to the biochemical steps between homocitric acid and a-amino-adipic acid. Similarly the genetic lesions in lys1, lys2, lys5, lys9, lys13, and lys14 correspond to the intermediate steps between a-aminoadipic acid and lysine. Lysine-genes are not clustered, instead are mapped on different chromosomes of Saccharomyces. Some of the intermediate steps in the biosynthesis of lysine correspond to two or more unlinked genes.

The effect of treatment of purified cholera enterotoxin with acid at pH 2.0 for 1 h followed by neutralization of the acid on the biological activity of the toxin has been studied. It was found that the material loses 85 to 96% of its skin permeability activity and this loss is neither reversed nor increased after 28 days of storage at 5 to 10 C. Other biological properties such as diarrheagenic activity, lipolysis-stimulating activity, and the lethal dose for mice remain unaffected by acid treatment. These observations indicate that the skin permeability activity is more sensitive to relatively minor changes in molecular structure than are the diarrheal, lipolytic, and mouse lethality activities.

A pectic material has been isolated from the bark of Abiesamabilis(Dougl.) Forbes in a yield of 2%. On hydrolysis it yielded D-galacturonic acid, D-galactose, and L-arabinose in a ratio of 85:4:11, and also traces of rhamnose. The product, when submitted to several conventional fractionation methods, appeared homogeneous. Further resolution could be effected by acidification of an aqueous solution of the pectin, followed by ultracentrifugation. The insoluble portion (50%) was an electrophoretically homogeneous galacturonanwith [α]D + 246°. The material remaining in solution (30%), here referred to as a pecticacid, had [α]D + 225° and on hydrolysis gave D-galacturonic acid, D-galactose, and L-arbabinose in a ratio of 74:7:19, as well as traces of rhamnose.The structure of the galacturonan was established by partial hydrolysis and methylation. It consisted of α-D-galacturonic acid residues linked together by (1 → 4)-glycosidic bonds to a linear macromolecule. The same techniques were applied to the pectic acid. While a unique structural formula could not be assigned in this case, one probable alternative involved a framework of (1 → 4)-linked α-D-galacturonic acid residues together with a few residues of 1,2,4-linked L-rhamnose. Some of the galacturonic acid units carried at C-2 and C-3 side chains which were terminated by D-galactopyranose and L-arabinofuranose residues. A few of the latter also occurred as inner units, probably in the side chains. This appears to be the first time a pectic material has been resolved into a galacturonan and a pectic acid containing the four sugar residues usually found in pectins. It is probable that the pectin occurring to a limited extent in wood has a similar composition.

Hydroxylysine acts as a growth inhibitor of Saccharomycesfor a certain period of time. The inhibition is concentration-dependent and is reversed by a small amount of lysine in the medium. After the growth-inhibitory period, the wild-type cells are able to grow rapidly even in the presence of hydroxylysine. Both lysine auxotrophs and wild-type cells are unable to utilize hydroxylysine in place of lysine. Hydroxylysine, mimicking lysine, controls the biosynthesis of lysine and thereby limits the availability of biosynthetic lysine to the cells. Hydroxylysine affects the biosynthesis of lysine at a number of enzymatic steps. Accumulation of homocitric acid, the first intermediate of lysine biosynthesis, in the mutant strains 19B and A B9 is reduced significantly in the presence of hydroxylysine. Hydroxylysine, like lysine, exerts a significant inhibition in vitro on the homocitric acid-synthesizing activity. Enzymes following the α-aminoadipic acid step respond in a noncoordinate fashion to hydroxylysine. Level of the enzyme saccharopine reductase, but not of α-aminoadipic acid reductase or saccharopine dehydrogenase, is reduced significantly. These regulatory effects of hydroxylysine are similar to those observed for lysine.

Aconitaseless glutamic acid auxotroph MO-1-9B of Saccharomycesgrew in glutamic acid-supplemented minimal medium, but failed to grow when glutamic acid was substituted by proline, arginine, ornithine, or glutamine. This mutant was also unable to utilize lactate or glycerol as a carbon source. Under a glutamic acid-limiting condition, by using acetate-1-14Cas tracer, the mutant accumulated rather large amounts of 14C-citric acid and 14C-succinic acid when compared with the wild-type strain. Under excess glutamic acid supplementation, accumulation of citric acid and succinic acid was considerably reduced. When 14C-glutamic acid-(U) was used as tracer, 14C-α-ketoglutaric acid, 14C-citric acid, and 14C-succinic acid were accumulated in the mutant. The citric acid peak was the largest, followed by α-ketoglutaric acid and succinic acid. In the wild-type strain under similar conditions, only small amounts of 14C-citric acid and 14C-succinic acid and no 14C-α-ketoglutaric acid were accumulated.

The absorption of amorphous and polymorph A forms of chloramphenicol palmitate suspensions made with polysorbate 80 was investigated in children, rhesus monkeys, and cats. In children, both forms were absorbed. While polymorph A was absorbed at a slower rate, maintaining the blood level of chloramphenicol for 6 hr., the amorphous form was absorbed maximally at 2 hr. followed by a profound fall in the blood level. Although the absorption of the amorphous form was definitely superior, the polymorph A form in suspension with a surface-active agent was also absorbed to a considerable extent in children, maintaining blood levels of chloramphenicol for a prolonged period. In experiments with cats, polysorbate 80 increased the absorption of both forms of chloramphenicol palmitate, with the amorphous variety having superior absorption. In rhesus monkeys, there was little absorption of the polymorph A form of chloramphenicol palmitate in suspension, possibly indicating the absorption as species specific.

Fresh young root tips or free-hand cross sections thereof were placed in 0.002 M 8-oxyquinoline (aq.) at 10-14oC. for 3 hours. After rinsing in water 1-2 minutes, they were soaked in N HC1 at 55oC. for 25 minutes, rinsed again and squashed under a cover glass on a dry slide. Slide and cover glass were separated by placing in 70% alcohol and allowed to remain therein at least 0.5 hour after separation. Both slide and cover glass were passed through 50% and 30% alcohol to water and stained by the Feulgen procedure (without further hydrolysis) or with crystal violet after mordanting in 1% chromic acid overnight and washing in running water 3-4 hours. Dehydration and mounting in balsam completed the process. The smear on the slide was covered with a clean cover glass and the cover glass, bearing stained material, mounted separately.

Abstract: Phytochemical survey results of 27 plant species from Mysore State (India) have been reported.

THE greater sensitivity of biological material to irradiation in the wet condition is due to the formation of radicals in the water surrounding the vital molecule. However, all the volume is not effective, since these radicals have a definite life-time and can diffuse only to a distance allowed by that time. This diffusion distance has variously been estimated from different types of inactivation studies in the wet and in the dry state of the molecules. Recently, the dependence of this distance on the shape of the molecule has been reported, and it has been shown that as the asymmetry of the target increases, the diffusion distance decreases1. In the present report this idea has been applied to the calculation of diffusion distance for the inhibition of colony-formation by E. coli exposed to β-rays from strontium-90.

Evidence indicated an accumulation of l-malic acid in the synthetic growth medium of both lysine auxotrophs and wild-type yeast. Malic acid was isolated from growth experiments and was identified by paper and column chromatography, by comparison of infrared spectra with authentic l-malic acid, as well as enzymatically, as a substrate of malic dehydrogenase. Malic acid was accumulated when glucose was used as a carbon source. This did not occur when sodium lactate was the carbon source. Malic, succinic, and citric acids, and a few other as yet unidentified organic acids, were accumulated in the culture supernatant fluid when yeast was grown in a chemically defined medium. The accumulation of these acids had no obvious relation to the pathway for lysine biosynthesis.

RIBONUCLEASE has been reported to influence the action of X-rays on E. coli1. This communication shows that the presence of ribonuclease during irradiation did not influence the percentage of survivors, but presence of ribonuclease after irradiation and during incubation at 37° C increased the survivor ratio to a very high value.

THE British Ministry of Health in 1941 made an appeal1for the cultivation within the Commonwealth of ergot, supplies of which had come hitherto from Central Europe, Spain and Portugal, where it occurs naturally. Wales and certain west coast places in England, and New South Wales, have taken up trial cultivation with a certain degree of success. English results are not definitely known; but the Australian ergot has an “alkaloid content well above the minimum standard provided in B.P., i.e. 0.05 per cent”2. In India, the Madras Agricultural Department3has taken up its experimental cultivation in the Nilgiri Hills and the produce has a similar alkaloid content.

THE demonstration of the property of hot trichloracetic acid in bringing about the dissociation of nucleic acid from nucleoproteins by Schneider1has led many authors in recent years to use it in different cytochemical experiments2–4. The protein framework of the chromosomes thus liberated provides a useful substrate for several biochemical procedures. Both ribo- and deoxyribo-nucleoproteins have been found to be affected by such treatments.

Culture filtrates of Escherichia coli from patients with diarrhea were tested for the ability to cause accumulation of fluid in intestinal loops of rabbits and dogs. Strains that caused fluid accumulation in rabbits also caused it in dogs. The time course of the enterotoxic effect in dogs was determined by measurement of serial fluxes of water and sodium in jejunal loops. These studies differentiated the effects of two enterotoxins, one rapid in onset, rinsable, and thermostable, the other late in onset, nonrinsable, and thermolabile. The thermolabile E. coli toxin resembled cholera toxin and was neutralized by cholera antitoxin.

Summary form only. An abstract of the above-titled article, taken from the 1963 IEEE International Convention (held March 25-28, New York, NY, USA), is presented.

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