Diurnal variations in activity of four pyridoxal enzymes in rat liver during metabolic transition from high carbohydrate to high protein diet.

The diurnal variations in enzyme activities including tyrosine aminotransferase (TAT), ornithine decarboxylase (ODC), ornithine aminotransferase (OAT) and serine dehydratase (SDH) have been studied in rats trained to a 2 hour meal feeding schedule (″2+22″) during metabolic transition from 12.5 to 60% protein diets over a period of 21 days. Although the maximal TAT activity on the first day was slightly lower compared with other days, both TAT and ODC activities adapted rapidly to the increased dietary protein from the first day. The responses of TAT and ODC to the food were so rapid that the maximal value was observed only 4 hrs after the onset of feeding. After each feeding ODC activity decreased rapidly after 4 hours, while TAT activity declined only after 6 hours had elapsed. No clear diurnal rhythm was observed in either OAT or SDH, though OAT activity tended to decrease from the beginning of the dark period and to resume a slow adaptation after about four hours. In contrast to ODC and TAT both OAT and SDH required about 7 days to fully adapt to the high protein diet. The activities of the four enzymes were also compared after 4 groups of rats had been adapted to the ″2+22″ feeding of 12.5, 30 and 60% protein diets and to 60% diet, $\text{ad}$$\text{libitum}$, respectively. The enzyme activities were not directly proportional to the protein content of the diets although higher activity was observed on the high protein diets. The diurnal variations in both TAT and ODC were observed in all ″2+22″ groups although the timing of the peak values were slightly different from each other. The maximal activities of TAT were found at earlier times in 12.5 and 30% protein groups than in the 60% protein group. The peak time for ODC activity was found at a later time in the 12.5% protein group than in rats fed 30% and 60% protein. $\text{Ad}$$\text{libitum}$ rats fed 60% protein maintained relatively high levels of TAT activity compared to the rats on the schedule. However, the maximal activity of ODC on the 60% ″2+22″ protein diet $\text{ad}$$\text{libitum}$ was so low that a diurnal rhythm was not clearly evident.     

Effects of the Brachyury (T) mutation on morphogenetic movement in the mouse embryo

$\text{T}\text{T}$ embryos have been first distinguishable at 8 days post coitum by their gross morphological abnormalities. By quantitative morphometry of histological sections, anomalies in the homozygotes were expressed numerically. At 8 days p.c., morphologically identifiable T-homozygotes had an increased number of ectodermal and a reduced number of mesodermal cells compared to the wild type. At 7 days p.c., embryos with a low mesoderm/ectoderm ratio were found only in litters of $\text{T}\text{+}\text{×}\text{T}\text{+}$ matings at the expected frequency. At 6 days p.c., one-fourth of the embryos in $\text{T}\text{+}\text{×}\text{T}\text{+}$ litters showed a delay in the transition from cuboidal to squamous endoderm. No such embryos were found in the +/+ × +/+ matings. In 6-, 7-, and 8-day mutant embryos, cells proliferated at statistically normal rates. Therefore, it may be said that advanced morphological irregularities of 8-day homozygotes cannot be accounted for by anomalies in cell proliferation. When the total cell number was 5 × 10⁴/embryo (8 days), a sudden change was observed in the regional distribution of mesodermal and ectodermal cells along the anteroposterior axis of $\text{T}\text{T}$ embryos. Since no regional difference in the cell cycle time was observed, these abnormalities may best be explained by anomalies in cell migration. These results strongly suggest abnormal morphology of $\text{T}\text{T}$ mutants resulting from defects in morphogenetic movement.     

Stimulation of leydig cell testoterone secretion in vitro and in vivo in hypophysectomized rats by an agonist of luteinizing hormone releasing hormone

Injection of a luteinizing hormone-releasing hormone (LHRH) agonist into 55-day-old male rats which had been hypophysectomized 3 days earlier resulted in a 10- to 30-fold increase in the levels of testosterone in serum and testicular interstitial fluid (IF) in the 4h following injection. The levels achieved were within or above the normal range for intact untreated rats of this age. In similar animals, injection of LHRH agonist also enhanced the serum testosterone response to injected hCG at $\text{1}\text{1}\text{2}\text{h}$, but not at later times after injection, and by 24h reduced IF levels of testosterone suggested that LHRH agonist had begun to inhibit stimulation by hCG. $\text{In vitro}$, dispersed Leydig cells from untreated hypophysectomized rats showed a 2-fold increase in testosterone responsiveness to LHRH agonist when compared to cells from intact rats, and this change was associated with an 80% increase in the number of Leydig cell LHRH-receptors.     

Saguinus geoffroyi as a host for Plasmodium vivax

A monkey-adapted strain of Plasmodium vivax (Achiote) was transferred by trophozoites through 11 serial passages in Saguinus geoffroyi (Titi marmoset). Patent infections developed in both normal (23 of 24) and splenectomized (8 of 9) marmosets. The infections in the altered animals were of greater severity than in the intact subjects as indicated by patent periods ($\text{x}\text{?}\text{= 87}\text{vs}\text{61}\text{days}$) and maximum parasitemias ($\text{x}\text{?}\text{= 35,018}\text{vs}\text{16,218}\text{per mm}{}^3$).Relapses were recorded in 13 of 14 unaltered and 4 of 4 splenectomized animals that survived the primary attack. As evidence for acquired immunity, the mean maximum parasitemias during relapse in the normal animals were $\text{1}\text{8}$ of the values during the primary attack; patent periods were shorter than those in the initial infection. There was also some indication of an acquired immunity in the splenectomized group of animals. However, one splenectomized marmoset experienced a patent period of 325 days during the first relapse.There was considerable variation of infection parameters among the animals in each group.     

Trypanosoma vivax: Courses of infection with three stabilates in inbred mouse strains

The courses of infection in inbred mouse strains were compared following infection with three Stabilates of high, intermediate, and low virulence of Trypanosoma vivax stock Zaria Y486. Mouse strains could only be shown to differ in their resistance to T. vivax infections as judged by the height of the initial parasitemia and survival times when a trypanosome population of low or intermediate virulence was used. A T. vivax population of high virulence was uniformly lethal. Comparison of lytic antibody titers between groups of resistant ($\text{C}\text{57}\text{B}\text{1}\text{6}$) and susceptible ($\text{Balb}\text{c}$) mice did not show any significant differences in titers of the surviving mice but the mice in either group which did not control the initial parasitemia had lower lytic antibody titers than those which did. A significantly larger number of $\text{Balb}\text{c}$ mice failed to control the initial infection as compared to the $\text{C}\text{57}\text{B}\text{1}\text{6}$. Treatment with cyclophosphamide did not ablate differences in susceptibility between the two strains. The use of congenic mice showed that these differences in susceptibility were not related to differences in the major histocompatibility complex between these strains.     

Trichinella spiralis: Characterization and strain distribution of rapid expulsion in inbred mice

Appropriately immunized mice display a response that is biologically equivalent to rat rapid expulsion. Only two inbred strains ($\text{NFR}\text{N}\text{and}\text{NFS}\text{N}$ derived from NIH Swiss mice) have been shown to respond in this manner. Mice of the $\text{Balb}\text{c}$, CBA, $\text{A}\text{He}$, C₃H, SJL, or C₅₇Bl strains are “nonresponders” which require approximately twice as much intestinal exposure (in days) to Trichinella spiralis to elicit a response half as effective. Genetically, the responder is dominant, autosomal, and does not appear to be linked to the MHC. The characteristics of mouse and rat rapid expulsion of T. spiralis are not identical but share these features: initial rejection within 24 hr of challenge; a rejection efficiency >90%, from 1 to 5 weeks after the primary; induction of response does not require exposure to the complete infection; rapid expulsion is immunologically specific for preadults; adult worms are resistant. While a genetic basis for responsiveness exists in mice there is, as yet, no evidence for genetic control in rats. In both mice and rats, rapid expulsion is distinguished from the intestinal hyperreactivity associated with rejection of the primary infection by the kinetics and amplitude of the rejection of transplanted adult worms.     

What determines the number of ovarioles in a fly ovary?

The relation between the size of a fly and the number of ovarioles in its ovary was investigated in Phormia regina and Sarcophaga bullata. Small flies of varying size were produced by taking larvae prematurely off the food. The smallest flies thus obtained were derived from larvae only $\text{1}\text{8}$ of the weight of a normal larva. The number of ovarioles in an ovary is directly proportional to the size of the fly and, in the extreme case, is about $\text{1}\text{5}$ the normal number in Sarcophaga and about $\text{1}\text{3}$ in Phormia. Larvae prematurely taken off the food, but fed again after starving for several days, grow to normal or almost normal size and develop ovaries with about the normal number of ovarioles. Small or re-fed Sarcophaga do not show any changes in the anatomy of individual ovarioles but in Phormia disorders in ovariole development and a consequent reduction of fertility are frequent. The number of ovarioles remains identical from the early pupal stage all through the development of the pharate fly and then through ovarian development in the adult fly: it is determined by the size of the larva when it was taken off the food. This shows that it is not lack of space in a small adult fly abdomen which determines the number nor the occurrence of degenerative processes during ovarian development.     

Trichomonas vaginalis: Dependence of resistance among different mouse strains upon the non-H-2 gene haplotype,sex, and age of recipient hosts

The genetic control of resistance or susceptibility to Trichomonas vaginalis infection has been studied in mice of various strains infected by different routes. $\text{BALB}\text{c}$ and $\text{DBA}\text{2}$ female mice appear to be highly susceptible to intraperitoneal, subcutaneous, or intravaginal infection by T. vaginalis. By contrast, female mice on A background are resistant to T. vaginalis infection via any route. $\text{C}\text{57}\text{BL}\text{6}$ and C3H female mice display intermediate levels of resistance following intraperitoneal or subcutaneous inoculum, whereas they display high levels of resistance to intravaginal infection. On the other hand, susceptibility or resistance to T. vaginalis infection appears to be influenced by the host sex, since males inoculated subcutaneously display much higher levels of resistance than females of the same strain. Lastly, the age of the host seems to play an important role in determining the course of infection. Susceptibility to T. vaginalis decreases with age, being maximal at 3–4 weeks and minimal at 40–42 weeks. All together these results suggest that resistance or susceptibility to T. vaginalis infection is regulated by genes mapping outside the major histocompatibility complex (H-2 in the mouse), whose activity is modulated by the anatomic site first coming into contact with the protozoon, the sex, and the age of the recipient host.     

Comparative studies between microbiological culture and uptake of uridine/uracil to detect mycoplasmal infection of cell cultures.

Controlled, prospective studies were performed to compare detection of cell culture mycoplasmas by ratio of uptake of tritiated uridine (UdR) to tritiated uracil (U) and by microbiological culture. Culture was by standard agar and broth inoculation with aerobic and anaerobic incubation; immunofluorescent staining of indicator cell cultures was used to detect M. hyorhinis. The ratio of uptake of UdR to U ($\text{UdR}\text{U}$) and interpretation of test results were by standard published methods and performed in triplicate. 115 cell cultures were simultaneously assayed by the two techniques. 84 cultures (73.1%) yielded agreement between the 2 methods; 2 cultures (1.7%) yielded conflicting results, and 29 cultures (25.2%) yielded $\text{UdR}\text{U}$ results in the questionable range. Conflicting results consisted of two negative $\text{UdR}\text{U}$ tests in mouse cell cultures infected with M. orale. In separate studies, 3T-6 cultures freshly infected with M. orale yielded negative $\text{UdR}\text{U}$ results 3 days after infection, questionable results after 10 days and a positive $\text{UdR}\text{U}$ 17 days after infection. $\text{UdR}\text{U}$ detected infection in fibroblast, epithelial, and lymphocyte cell cultures. Highest $\text{UdR}\text{U}$ ratios were detected in human skin fibroblasts at early population doubling levels (PDLs), 4064 in one culture at PDL4. $\text{UdR}\text{U}$ was determined for IMR-90, a human diploid fibroblast at 12 different PDLs using the same lot of media. $\text{UdR}\text{U}$ gradually decreased throughout the life of the culture, from 2 125 at PDL6 to 340 at PDL36. Cultures in phase III and others exhibiting poor growth frequently yielded questionable or false-positive $\text{UdR}\text{U}$ results and were not included in tabulations of these results. $\text{UdR}\text{U}$ determined in endothelial cell cultures decreased as population density increased. In a representative experiment performed over a 4-day period, the $\text{UdR}\text{U}$ values were 1 808, 955 and 356 when the number of endothelial cells in culture were 5.3 × 10⁵, 6.6 × 10⁵ and 1.1 × 10⁶, respectively.     

Babesia major in Britain: blood-induced infections in splenectomized and intact calves

A strain of Babesia major, originally isolated from field collections of Haemaphysalis punctata in Kent, England was maintained in splenectomized calves by the intravenous inoculation of infected blood. Rapid passage from carrier calves, that had recovered from a tick-induced infection, resulted in a marked increase in virulence; 4 out of 6 calves of the second passage underwent fatal infections and the others suffered severe reactions.Five splenectomized and 5 intact calves of the same breed and age were infected with the same number of infected erythrocytes (RBC). The intact calves reacted mildly with maximum parasite counts ranging from < $\text{1}\text{1000}$ RBC to $\text{5}\text{1000}$ RBC; haemoglobin levels and packed cell volume values, however, fell sharply but recovered swiftly. The group of splenectomized calves exhibited one fatal case, 2 severe reactions and 2 mild infections; maximum parasitaemias varied from $\text{7}\text{1000}$ RBC to $\text{322}\text{1000}$ RBC. Packed cell volumes and haemoglobin concentrations declined to low levels and took several weeks to return to normal.It is concluded that B. major should be regarded as a potential pathogen of British cattle.     

Effects of age and sex on the induction by triiodothyronine of cortisone delta4-5alpha-reductase and glucose 6-phosphate dehydrogenase of rat liver and adrenal

The effects of age and sex on the induction by 3,5,3′-triiodothyronine (T-3) of cortisone Δ⁴-5α-reductase and glucose 6-phosphate dehydrogenase (G 6-P D) in liver and the latter in adrenal have been investigated. Levels of cortisone Δ⁴-(5α, 5β)-reductase and G 6-P D were measured in homogenates of tissue from normal and T-3 injected male and female rats, $\text{1 1}\text{4}$ to 21 months of age. Increases in the levels of the reductase seen under T-3 stimulation were ascribed to induction of the 5α-reductase alone. T-3 caused induction of cortisone Δ⁴-5α-reductase only in the livers of male rats $\text{1}\text{3}\text{4}$ months of age. There was induction of total G 6-P D at most ages except in the livers of old male and young female rats and adrenals of young and old male rats. At all ages in normal animals of both sexes the maximum activity of glucose 6-phosphate dehydrogenase was much greater than that of cortisone Δ⁴-(5α, 5β)-reductase. It is concluded that the amount of G 6-P D in normal liver may be sufficient to handle an increase in cortisone reduction, and factors other than cortisone Δ⁴-reductase or G 6-P D levels alone must regulate increased reduction of the steroid.     

Hymenolepis nana: Immunogenicity of a lumen phase of the direct cycle and failure of autoinfection in BALBc mice

When $\text{BALB}\text{c}$ mice were given $\text{BALB}\text{c}$ mouse-derived cysticercoids (cysts) of Hymenolepis nana, only $\text{1}\text{43}$ mice became autoinfected, whereas most ($\text{31}\text{38}$) of dd mice given the same infection became massively autoinfected with mature worms. When $\text{BALB}\text{c}$ mice initially given cysts were challenged with eggs on Day 7, just before the patency of the primary infection, there was normal development into cysts, but almost none of them developed into adult worms. Thus, the failure of autoinfection of H. nana in $\text{BALB}\text{c}$ mice was not a result of failure of eggs to differentiate into cysts in the intestinal tissue, but a result of failure of these cysts to develop into adult worms in the lumen. The reasons why autoinfection does occur in dd and other strains of mice and not in the $\text{BALB}\text{c}$ strain are discussed in terms of the difference in onset of the late response in these strains of mice, ie., the response that is acquired after egg inoculation, and is directed against the lumen phase of cyst challenges. It is strongly suggested that (1) the lumen phase which follows cyst inoculation is highly immunogenic, but clearly differs from tissue phase which follows egg inoculation, (2) the autoinfection which occurs in some strains of mice is therefore not a result of no or poor immunogenicity of the lumen phase but is due to a delay of onset of the late response with the result that a secondary generation may mature, and (3) in other strains of mice, including $\text{BALB}\text{c}$, which acquire the late response within 15 days of initial egg inoculation, autoinfection normally does not occur after cyst infections.     

Embryonic development in repeat breeder and virgin heifers seven days after insemination

The aim of this study was to compare the development of embryos from repeat breeder heifers with that of embryos from virgin heifers at 7 days after standing heat. A total of 23 repeat breeder heifers (RBH) and 18 virgin heifers (VH) were utilized. The heifers were between 16 and 30 months of age and most of them were of the Swedish Red and White Breed. Two RBH were heterozygous for the $\text{1}\text{29}$ chromosome translocation, one RBH was a trisomy X and all the other heifers had normal karyotypes. All heifers were inseminated with frozen semen from the same bull and all inseminations were performed by the author. The fertility of the bull was above the average for the AI association to which it belonged. Embryos were collected by a non-surgical technique (89) or after slaughter (19). The morphology of the embryos was examined under a phase-contrast microscope and they were classified as being normal (N), morphologically deviating (MD) or degenerated (D). Thirteen embryos from RBH and 15 from VH were examined for total cell numbers after examination of their morphology.There was no significant difference in recovery rates of embryos between RBH (68%) and VH (76%) but independent of collection method the recovery rate of embryos from VH was numerically higher. The fertilization rate was high in both RBH (89%) and VH (97%). Seventyfour percent of the embryos collected from VH were normal ($\text{23}\text{31}$) while only 28% ($\text{11}\text{40}$) of the embryos collected from RBH had a normal morphology. The difference in number of normal embryos recovered from the two groups of heifers was highly significant (P < 0.005). Exclusion of the RBH heifers with deviating karyotype did not influence this difference. However, there was a tendency to a higher incidence of fertilization failure and morphologically deviating embryos in these heifers. The N embryos had significantly higher total cell numbers (P < 0.005) than the MD embryos but there was no significant difference in total cell numbers between N embryos from RBH or VH.The results of this study strongly indicate a higher incidence of abnormal embryos in RBH than in VH. It is likely that these deviations are followed by an increased incidence of early embryonic death.     

An ultrastructural examination of everted rat jejunum

Male, albino, Sprague-Dawley rats were sacrificed by cervical separation. Segments of jejunum were excised, everted and examined with the electron microscope. Examination of tissue fixed immediately after eversion revealed the following changes as compared to non-everted segments fixed $\text{in}$$\text{situ}$ and $\text{in}$$\text{vitro}$: 1) an increase in the length of microvilli from (mean ± S. E.) 0.991 ± 0.011μ for normal tissue to 1.389 ± 0.023μ for everted tissue, 2) an increase in width of microvilli from (mean ± S. E.) 0.089 ± 0.001μ for normal tissue to 0.097 ± 0.001μ for everted tissue, 3) an increase in length and number of lateral membrane interdigitations, and 4) the appearance of intercellular “lakes” in the lateral spaces. The above changes are in those structures hypothesized to be involved with salt and water transport across epithelia and may reflect altered transport rates $\text{in}$$\text{vitro}$ as compared to $\text{in}$$\text{vivo}$.     

Plasma progesterone concentration in Bos taurus and Bos indicus heifers

Progesterone concentrations were determined by radioimmunoassay in the plasma of heifers of German Brown Swiss, Holstein-Friesian and White Fulani cattle during two consecutive estrous cycles in the dry and wet seasons in a tropical climate. Seasonal differences in the levels were not significant but peak levels were significantly higher in the $\text{Bos}$$\text{taurus}$ than in the $\text{Bos}$$\text{indicus}$ heifers. The low levels at estrus and the gradual rise five days after estrus were similar among the heifers. The levels on the 1st and 2nd days preceding estrus were significantly higher in the $\text{Bos}$$\text{taurus}$ than in the $\text{Bos}$$\text{indicus}$ heifers, and suggest a possible tendency for the former to be more susceptible to infertility arising from high progesterone levels 1 and 2 days preceding estrus and insemination. The genital tract and ovaries at the mature luteal phase were generally smaller in the $\text{Bos}$$\text{indicus}$ than in the $\text{Bos}$$\text{taurus}$ heifers.     

Effect of sex hormones on the growth and multiplication of tetrathyridia of Mesocestoides corti (Cestoda: Cyclophyllidea) in mice

The number of tetrathyridia in the peritoneal cavities of mice increases exponentially with time. Thirty days post infection more larvae are in the cavities than in the livers. After that the increase of intraperitoneal populations continues, whereas the number of tetrathyridia in the livers remains more or less constant.Exogenous testosterone propionate, 10 $\text{μg}\text{g}$, twice a week, for 5 weeks, increases significantly the total volumes of tetrathyridial populations in the peritoneal cavities, whereas oestradiol benzoate, 5 $\text{μg}\text{g}$ or 10 $\text{μg}\text{g}$, also for 5 weeks, accelerates the rate of growth and multiplication of coelomic tetrathyridia to a much lesser extent, but increases significantly the infection of the livers.     

An organ culture system for study of fetal lung development

Fetal rat lungs placed in $\text{in}$$\text{vitro}$ organ culture at 15.5 days gestation grow significantly based on accumulation of DNA and protein. In the experimental system described, DNA accumulated rapidly during the first three days in culture and increased from 4.8 to 15.6 micrograms per lung culture. Protein content increased more slowly and reached a value more than double the initial value after six days in the culture system. Glycogen accumulated in the tissue during the first six days in culture and was depleted during the subsequent culture period, a pattern strikingly similar to that observed during lung development $\text{in}$$\text{vivo}$. Phospholipid accumulation was biphasic with respect to time with an inflection point at about the sixth day of culture. The phosphatidylcholine species synthesized in the culture system $\text{in}$$\text{vitro}$ were similar to those produced $\text{in}$$\text{vivo}$ in fetal lung at 21 days gestation.     

Increased synthesis of L-glycerol 3-phosphate dehydrogenase during in vitro differentiation of reaggregating cerebellar cells

Reaggregating cell cultures of neonatal mouse cerebellar cells express many of the differentiated properties of normal developing cerebellum, including the transition for the embryonic and adult isozymes of l-glycerol 3-phosphate dehydrogenase (EC 1.1.1.8). In order to determine the mechanism leading to increased levels of adult isozyme, aggregates in culture from 2 to 17 days were labeled with radioactive leucine and the relative rate of enzyme synthesis was measured after purification of the enzyme by affinity chromatography on Blue Sepharose 6B. During the course of in vitro differentiation, the relative rate of synthesis increased 100-fold, such that it represented 0.5% of the total protein synthesized in the cytoplasmic fraction of the cell. In vivo, $\text{BALB}\text{cBy}$ mice have twice the level of enzyme activity in the cerebellum as do $\text{C57BL}\text{6J}$ mice. Reaggregating cell cultures of cerebellar cells from these strains of mice also express a difference in the activity level, but only when the cerebellar cells are taken from mice 4 days of age or less. When the relative rates of synthesis of l-glycerol 3-phosphate dehydrogenase were measured in cultures expressing the strain-dependent difference in activity, these rates were found to be approximately twofold greater in cultures of $\text{BALB}\text{cBy}$ cells. In contrast, estimates of the relative rate of enzyme degradation by the double-isotope labeling technique indicate that neither specific enzyme degradation nor degradation of total protein is different in aggregates from the two strains of mice. The results suggest that the genetic mechanisms controlling the levels of l-glycerol 3-phosphate dehydrogenase in the cerebellum during development are intrinsic to the cells and, with the exception of serum factors, are independent of systemic influences.     

myo-Inositol metabolism in rat testis in response to streptozotocin-induced diabetes

The effects of streptozotocin-induced hyperglycemia on de novo myo-inositol biosynthesis in rat testis was examined. Testicular glucose and glucose 6-phosphate levels increased significantly 10 and 12 h after stretozotocin injection, respectively. However, testis myo-inositol content did not increase appreciably until 24 h following injection of the drug. Seventy-two hours after streptozotocin administration, testis myo-inositol levels were 2.7-fold higher in diabetic rats than in controls injected with citrate buffer. No changes were observed in the Specific activities of myo-inositol-1-phosphate synthase (EC 5.5.1.4) and 1-l-myo-inositol-1-phosphatase (EC 3.1.3.25). However, hyperglycemic rats displayed testicular glucose and glucose 6-phosphate levels approximately 4- and 2-fold in excess of control values, respectively. Insulin treatment of diabetic rats resulted in the lowering of plasma glucose, and testis glucose 6-phosphate to normal or below normal levels within hours. Inositol levels remained significantly elevated compared with control animals, although slightly lower than that observed for untreated diabetic rats. Streptozotocin diabetic rats had a significantly decreased testis cytosolic $\text{NAD}{}^{\mathrm{+}}\text{NADH}$ ratio compared with control animals 72 h after injection. The potential role of testis hexokinase distribution in the regulation of glucose 6-phosphate and myo-inositol biosynthesis in normal and diabetic rats was investigated. No significant differences in testis hexokinase distribution or in the kinetic characteristics of the soluble and particulate hexokinase activities were observed. Testicular sperm counts in streptozotocin diabetic rats were not significantly different from control values.     

Cytokinins in tobacco crown gall tumors

Bacteria-free tobacco ($\text{Nicotiana tabacum}$ cv. Wisconsin #38) crown gall strains incited by $\text{Agrobacterium tumefaciens}$ C58, 27, B6, CGIC, and AT4 have been analyzed for cytokinin content with the tobacco callus bioassay. All tumor strains contained high total levels of cytokinins ranging from 4–810 kinetin equivalents per kg fresh weight compared to 0.5 kinetin equivalents per kg for normal callus growing on medium with 0.1 μM N6-benzyladenine. Fractionation on a column of Sephadex LH-20 separated cytokinin activity from B6 tumors into a number of components among which ribosyl-$\text{trans}$-zeatin has been purified and characterized based on uv spectrum, biological activity and mass spectrum.