Impact of Supplementing a Backgrounding Diet with Nonprotein Nitrogen on In Vitro Methane Production, Nutrient Digestibility, and Steer Performance.

Two experiments were conducted to evaluate the effect of nonprotein nitrogen (NPN) supplementation on in vitro fermentation and animal performance using a backgrounding diet. In experiment 1, incubations were conducted on three separate days (replicates). Treatments were control (CTL, without NPN), urea (U), urea-biuret (UB), and urea-biuret-nitrate (UBN) mixtures. Except for control, treatments were isonitrogenous using 1% U inclusion as a reference. Ruminal fluid was collected from two Angus-crossbred steers fed a backgrounding diet plus 100 g of a UBN mixture for at least 35 d. The concentration of volatile fatty acids (VFA) and ammonia nitrogen (NH3-N), in vitro organic matter digestibility (IVOMD), and total gas and methane (CH4) production were determined at 24 h of incubation. In experiment 2, 72 Angus-crossbred yearling steers (303 ±â€…29 kg of body weight [BW]) were stratified by BW and randomly allocated in nine pens (eight animals/pen and three pens/treatment). Steers consumed a backgrounding diet formulated to match the diet used in the in vitro fermentation experiment. Treatments were U, UB, and UBN and were isonitrogenous using 1% U inclusion as a reference. Steers were adapted to the NPN supplementation for 17 d. Then, digestibility evaluation was performed after 13 d of full NPN supplementation for 4 d using 36 steers (12 steers/treatment). After that, steer performance was evaluated for 56 d (24 steers/treatment). In experiment 1, NPN supplementation increased the concentration of NH3-N and VFA (P < 0.01) without affecting the IVOMD (P = 0.48), total gas (P = 0.51), and CH4 production (P = 0.57). Additionally, in vitro fermentation parameters did not differ (P > 0.05) among NPN sources. In experiment 2, NPN supplementation did not change dry matter and nutrient intake (P > 0.05). However, UB and UBN showed lower (P < 0.05) nutrient digestibility than U, except for starch (P = 0.20). Dry matter intake (P = 0.28), average daily gain (P = 0.88), and gain:feed (P = 0.63) did not differ among steers receiving NPN mixtures. In conclusion, tested NPN mixtures have the potential to be included in the backgrounding diets without any apparent negative effects on animal performance and warrant further studies to evaluate other variables to fully assess the response of feeding these novel NPN mixtures.

Nonprotein nitrogen (NPN) supplements can be used as a nitrogen source for ruminants fed low-protein diets. The most common NPN source is urea, included typically at a range between 0.5% and 1% of the diet dry matter in growing beef cattle. Although other NPN sources and mixtures are available, there is scarce information regarding their use in ruminant production. Two experiments were conducted to evaluate the effect of NPN sources on in vitro fermentation and animal performance using a backgrounding diet. In experiment 1, three different incubations were performed for 24 h. Treatments were control (without NPN), urea (U), urea­biuret (UB), and urea­biuret­nitrate (UBN) mixtures. In experiment 2, 72 crossbred yearling steers were randomly assigned to one of the following treatments: U, UB, and UBN mixtures. Diets were formulated to contain the same nitrogen concentration in both experiments. In experiment 1, supplementation of NPN increased the in vitro fermentation, but there were no differences among NPN sources. In experiment 2, steers performed similarly among NPN sources. These findings suggest that NPN mixtures have the potential to be included in the backgrounding diets without detrimental effects. Further studies should evaluate other variables (e.g., fermentation dynamic and microbial protein supply) when using these novel mixtures.

In silico and in vitro comparative activity of novel experimental derivatives against Leishmania major and Leishmania infantum promastigotes.

This in silico and in vitro comparative study was designed to evaluate the effectiveness of some biurets (K1 to K8) and glucantime against Leishmania major and Leishmania infantum promastigotes. Overall, eight experimental ligands and glucantime were docked using AutoDock 4.3 program into the active sites of Leishmania major and Leishmania infantum pteridine reductase 1, which were modeled using homology modeling programs. The colorimetric MTT assay was used to find L. major and L. infantum promastigotes viability at different concentrations of biuret derivatives in a concentration and time-dependent manner and the obtained results were expressed as 50% and 90% of inhibitory concentration (IC50 and IC90). In silico method showed that out of eight experimental ligands, four compounds were more active on pteridine reductase 1. K3 was the most active against L. major promastigotes with an IC50 of 6.8 µM and an IC90 of 40.2 µM, whereas for L. infantum promastigotes was K8 with IC50 of 7.8 µM. The phenylethyl derivative (K7) showed less toxicity (IC50s>60 µM) in both Leishmania strains. Glucantime displayed less growth inhibition in concentration of about 20 µM. In silico and especially docking results in a recent study were in accordance with the in vitro activity of these compounds in presented study and compound K3, K2 and K8 showed reasonable levels of selectivity for the Leishmania pteridine reductase 1.

Synthesis, antibacterial and cytotoxic activity evaluation of hydroxyurea derivatives.

5 Synthesis and biological evaluation of a series (N = 16) of cyclic and acyclic hydroxyurea derivatives, including benzotriazole-, isocyanuric acid- and biuret-containing compounds, are disclosed. 1-N-(benzyloxycarbamoyl)benzotriazole was used as a benzyloxyisocyanate donor, a useful intermediate in the preparation of substituted hydroxyurea. Antibacterial activities of synthesized hydroxyurea derivatives were tested on three E. coli strains, i.e., a strain susceptible to antibiotics, a strain resistant to macrolide antibiotics and a strain resistant to aminoglycoside antibiotics. Six compounds (three acyclic and three cyclic hydroxyureas) showed growth inhibition of the tested E. coli strains, with different specificity toward each strain. Results of the cytotoxic activity evaluation revealed that twelve out of sixteen test compounds were cytotoxic to human acute monocytic leukemia THP-1 and/or human acute T cell leukemia Jurkat cell line. 1-(N-hydroxycarbamoyl) benzotriazole () increased the metabolic activity of both cell lines. Two compounds, 1-(N-hydroxycarbamoyl) benzotriazole (5) and N,N',N''-trihydroxybiuret (15), were identified as potential NO donors.

Synthesis of new glycosyl biuret and urea derivatives as potential glycoenzyme inhibitors.

O-peracetylated 1-(beta-D-glucopyranosyl)-5-phenylbiuret was prepared in the reaction of O-peracetylated beta-D-glucopyranosylisocyanate and phenylurea. The reaction of O-peracetylated N-beta-D-glucopyranosylurea with phenylisocyanate furnished the corresponding 1-(beta-D-glucopyranosyl)-3,5-diphenyl- as well as 3-(beta-D-glucopyranosyl)-1,5-diphenyl biurets besides 1-(beta-D-glucopyranosyl)-3-phenylurea. O-Peracetylated 1-(beta-D-glucopyranosyl)-5-(beta-D-glycopyranosyl)biurets were obtained in one-pot reactions of O-peracetylated beta-D-glucopyranosylamine with OCNCOCl followed by a second glycopyranosylamine of beta-D-gluco, beta-D-galacto and beta-D-xylo configurations. O-Acyl protected 1-(beta-D-glucopyranosyl)-3-(beta-D-glycopyranosylcarbonyl)ureas were obtained from the reaction of beta-D-glucopyranosylisocyanate with C-(glycopyranosyl)formamides of beta-D-gluco and beta-D-galacto configurations. The O-acyl protecting groups were removed under acid- or base-catalyzed transesterification conditions, except for the N-acylurea derivatives where the cleavage of the N-acyl groups was faster than deprotection. Some of the new compounds exhibited moderate inhibition against rabbit muscle glycogen phosphorylase b and human salivary alpha-amylase.

Perfil eletroforético das proteínas e concentraçäo das imunoglobulinas plasmáticas em pacientes assintomáticos e sintomáticos portadores de HIV / Proteins electrophoretic profile and immunoglobulins plasmatics concentration in asymptomatics and symptomatics patients infected by HIV

Estudos têm demonstrado que 81 por cento dos pacientes infectados pelo HIV apresentam um padräo proteico anormal devido ao estado hipermetabólico. Os achados laboratoriais revelam que as anormalidades da imunidade humoral precedem a imunidade mediada pelas células e portanto, o diagnóstico da infecçäo pelo HIV depende do estabelecimento da infecçäo definindo o estado imunológico e o quadro clínico do paciente que ocorre secundário à infecçä e à perda da funçäo imune. No presente trabalho, realizamos um estudo comparativo do perfil eletroforético das proteínas, bem como a determinaçäo da concentraçäo das imunoglobulinas plasmáticas em pacientes portadores de HIV (assintomáticos e sintomáticos) com o objetivo de investigarmos alteraçöes específicas das fraçöes protéicas (albumina e globulina) durante os diferentes estágios da doença. Foram analisadas 30 amostras de sangue coletado de pacientes HIV positivos divididos em dois grupos (assintomáticos e sintomáticos). As proteínas totais foram determinadas pelo método do Biureto, sendo observada uma hipoproteinemia em 60 por cento dos pacientes sintomáticos e valores normais em todos os assintomáticos. A eletroforese das proteínas foi realizada em gel de agarose mostrando hipoalbuminemia em 70 por cento dos pacientes assintomáticos e 90 por cento sintomáticos. A hipergamaglobulinemia predominou em 100 por cento dos sintomáticos e 90 por cento dos assintomáticos. As fraçöes alfa e beta globulinas apresentaram-se normais nos dois grupos. As imunoglobulinas foram avaliadas por turbidimetria e uma elevaçäo significativa foi verificada na concentraçäo de IgG em todos os pacientes sintomáticos. Por outro lado, os valores de IgA e IgM apresentaram-se dentro dos valores de referência. Os resultados estäo de acordo com vários trabalhos citados na literatura, comprovando que a AIDS é uma gamopatia monoclonal, caracterizada por hipoalbuminemia e hipergamaglobulinemia. O trabalho mostra portanto, que, a avaliaçäo de parâmetros laboratoriais mais simples säo úteis no monitoramento da síndrome em estudo, como também fortes indicadores do estágio da doença.

Syntheses, antiinflammatory, and analgesic activities of arylbiurets.

A number of arylbiurets were prepared and evaluated as antiinflammatory and analgesic agents by using the carrageenan paw edema and acetic acid stretching tests. Among them, the antiinflammatory activity of 1,3-dimethyl-5-phenylbiuret (7), 1-ethyl-3-methyl-5-phenylbiuret (11), and 1,1,3-trimethyl-5-phenylbiuret (13) were found to be more potent than phenylbutazone. The analgesic activity of 7 and of 5-(4-chlorophenyl)-1,1,3-trimethylphenylbiuret (16) is higher than that of aminopyrine.

Synthesis and biological activity of isodithiobiurets, dithiobiurets, and dithiazoles.

A series of isodithiobiurets, dithiobiurets, and dithiazoles was synthesized and tested for biological activity. Generally, the compounds potentiated the hypnosis induced by pentobarbitone (50 mg/kg ip) in albino mice and exhibited antifungal and insecticidal activity against Fusarium oxysporum and Periplanata americana, respectively. Some compounds showed anticonvulsant and analgesic activity in albino rats.

[Penicillin formation by biochemical mutants of Penicillium chrysogenum and their spontaneous revertants]. / Obazovanie penitsillina biokhimicheskimi mutantami Penicillium chrysogenum i ikh spontannymi revertantami.

The capacity for the antibiotic production in the auxotrophs of Penicillium chrysogenum with various deficiency and their revertants was studied. It was found that the capacity for penicillin synthesis was impaired to various degrees in the majority of the auxotrophs. Variants with the penicillin production levels by 13--20 per cent higher than those in the initial prototrophic strain were isolated for the first time in selection of the eukaryotes with the method of obtaining highly active revertants from auxotrophs according to the scheme "prototroph-auxotroph-prototroph".

[Ratio of the mutation spectrum to the physiological state of the Penicillium chrysogenum cell. Auxotrophic mutations induced by N-nitroso-N-methylbiuret in exposure at different stages of DNA replication]. / Zavisimost' spektra mutatsii ot fiziologicheskogo sostoianiia kletki Penicillium chrysogenum. Auksotrofnye mutatsii, indutsirovannye N-nitrozo-N-metilbiuretom pri vozdeistvii na raznye stadii replikatsii DNK.

The effect of UV light on activated conidia of Penicillium chrysogenum, strain 39 was studied. It was found that the spectrum of the auxotrophic mutations induced by UV light during replication of DNA changed with the dose of the mutagen and was specific to every dose. The schemes of predominating mutation induction during DNA replication under the effect of 2 doses of UV light were developed.

[Exclusion of propyl alcohol from the medium for culturing the erythromycin producer]. / Iskliuchenie propilovogo spirta iz sredy dlia kul'tivirovaniia produtsenta éritromitsina.

Propyl alcohol is a precursor of erythromycin. It is one of the components of the medium for production of the antibiotic. Still, this raw material has an unfavorable effect on employees and is fire hazardous. The results of the development of the erythromycin-producing organism are presented. A strain requiring no propyl alcohol as a precursor in the medium and producing the same amounts of the antibiotic was obtained by means of step-wise selection with the use of a mutagen.

[Variability of a Cephalosporium acremonium culture for 2 quantitative traits: antibiotic formation and proteolytic activity]. / Izmenchivost' kul'tury Cephalosporium acremonium po dvum kolichestvennym priznakam--antibiotikoobrazovaniiu i proteoliticheskoi aktivnosti.

Exposure of Cephalosporium acremonium, strain 1435, to N-nitrozo-N-methylbiuret resulted in a changed variation coefficient with respect to two quantitative features--the antibiotic production and proteolytic activity. Correlation between the variation coefficient and mutagen exposure time was different for every feature. Positive correlation was found in variation with respect to the antibiotic production and proteolytic activity in populations of various Cephalosporium acremonium strains chosen with regard to one or two of the above features. The level and form of the correlation in variation of the above features in populations changed during selection. Selection according to the two quantitative features resulted in an increased correlation coefficient.

[Selection of Trichoderma viride, a producer of cellulase]. / Selektsiia Trichoderma viride--produtsenta tselliulazy.

A mutant strain of Trichoderma viride producing cellulase has been obtained as a result of three-stage selection using chemical and physical factors. New variants with modified characteristics appeared after the action of nitroso compounds on a suspension of conidia at the first stage of selection and the action of temperature at the second stage. The new characteristics were intensified and became stable at the third stage of selection. The experimental mutagenesis yielded an active an active mutant of Trichoderma viride 44 which synthesized cellulase (up to 22 units/ml) four times better than the parent culture Trichoderma viride F-57.

[Biosynthesis of the antibiotic, grizin, by prototrophic revertants of Streptomyces griseus biochemical mutants]. / Biosintez antibiotika grizina prototrofnymi revertantami biokhimicheskikh mutantov Streptomyces griseus.

Spontaneous and nitrosomethylbiuret-induced prototrophic revertants of various biochemical mutants of Str. griseus producing grisin, a streptothricin antibiotic, were isolated. The antibiotic production level of the revertants was studied. It was found that most of the prototrophic revertants synthesized much higher amounts of grisin than the initial biochemical mutants. It was also shown that a number of the prototrophic revertants of the methionine- and arginine-dependent mutants synthesized 20-23% higher amounts of grisin as compared to the control.

[Lethal and mutagenic action of N-nitroso-N-methylbiuret on the producers of levorin, amphotericin and mycoheptin]. / Letal'noe i mutagennoe deistvie N-nitrozo-N-metilbiureta na produtsenty levorina, amfoteritsina i mikogeptina.

The lethal and mutagenic effect of N-nitrozo-N-methylbiuret (NMB) on the organisms producing levorin, amphotericin B and mycoheptin was studied. The mutagen effect depended on the dose, culture and physiological state of the spores. NMB had a low mutagenic effect on the levorin-producing organism characterized by high activity and genetic homogenicity with respect to the colony morphology and antibiotic production. As for the organisms producing amphotericin B and mycoheptin characterized by high genetic heterogenicity, significant variation of all the features studied was observed on their exposure to the mutagen. Inspite of diverse reaction of the organisms producing levorin, amphotericin B and mycoheptin to the effect of NMB mutants with increased antibiotic production were obtained from the three cultures. The lethal and mutagenic effect of NMB on the mycoheptin-producing organism depended on the process of the spore DNA replication. The spores during the DNA replication period were least sensitive to the lethal effect of the mutagen and most mutable with the respect to the colony morphology. For selection of highly active and stable strains exposure to NMB of the spores of the mycoheptin-producing organism during replication of DNA proved to be more effective than that of the spores during the lag-phase.

[Actinomyces streptomycini mutants blocked in the biosynthesis of the streptobiosamine portion of the streptomycin molecule]. / Mutanty Actinomyces streptomycini, blokirovannye po biosintezu streptobiozaminovoi chasti molekuly streptomitsina.

Four low active mutants of Act. streptomycini were obtained under the effect of nitrozo-methylbiuret. The mutants increased their antibiotic production level, when streptobiosamine was present in the formentation medium. It was shown that in 3 out of the 4 mutants the highest antibiotic yield was in the medium containing streptobiosamine in an amount of 1 mg/ml and in 1 strain the highest yield was in the medium with 0.5 mg/ml of streptobiosamine. When the mutants were grown in a medium containing N-methyl-L-glucosamine no increase in streptomycin production was registered.

[Lethal and mutagenic action of nitrosomethylbiuret on a culture of the mycophilic fungus, Didymocladium ternatum]. / Letal'noe i mutagennoe deistvie nitrozometilbiureta na kul'turu mikofil'nogo griba Didymocladium ternatum

The effect of N-nitrozo-N-methylbiuret (NMB) on various features of Didymocladium ternatum, an organism producing termatin was studied. It was found that the lethal effect of NMB depended on the exposure time, prolongation of which resulted in increased numbers of the plus variants, morphological mutations and reverses into the populations. Variants possessing 8 times higher activity as compared to the initial culture were obtained as a result of selection of active variants.

[Dependence of the mutagenic effect of N-nitroso-N-methylbiuret on the pH index]. / Zavisimost' mutagennogo éffekta N-nitrozo-N-metilbiureta ot pokazatelia pH

The mutagenic effect of nitrosocompounds is known to be dependent on pH. The effect of N-nitrozo-N-methylbiuret on the conidia of Penicillium chrysogenum was studied within the ranges of pH from 5.0 to 7.0, the role of the buffer and distilled water being also considered. It was found that survival, morphological variation and induction of biochemical mutants depended on the value of pH. The optimal conditions for the culture treatment at the exposures tested were provided at pH 6.0 with the use of a phosphate buffer mixture as a substrate.

[Variability in Act. circulatus var. monomycini induced by N-5-nitroso-N-methylbiuret]. / Izmenchivost' Act. circulatus var. monomycini, indutsirovannaia N-5-nitrozo-N-metilbiuretom.

The effect of N-5-nitrozo-N-methylbiuret (NMB) on various features of Act. circulatus var. monomycini, an organism producing monomycin was studied. It was found that the lethal effect of NMB depended on the exposure time, prolongation of which resulted in increased numbers of the plus variants, morphological and auxotrophic mutations and reverses into the populations of the monomycin-producing organism. An increase in the temperature of the treatment had an effect on the frequency of morphological and auxotrophic mutations inducing an increase in the number of the first and some decrease in the number of the second. The fact of specificity in formation of the vitamin B6-deficient auxotrophic mutants of the same type was of special interest. This was probably associated with genetic peculiar properties of the culture. It was supposed that the genes controlling biosynthesis of vitamin B6 were localized on the actinomycete plasmids, elimination of which under the effect of NMB resulted in blocking of vitamin B6 synthesis which in its turn impaired the reactions of transaminations participating in formation of monomycin.

[Isolation and characteristics of UV-resistant revertants of recA-strains of Escherichia coli K-12]. / Vydelenie i kharakteristika UF-rezistentnykh revertantov recA-shtammov Escherichia coli K-12

The paper presents the results of a study of UV-resistant revertants of some recA strains induced by different mutagens. It is shown that some of produced revertants differ from original recA strains in some properties. It is established that all UV-resistant revertant fall into three phenotypic groups on their recombination proficiency in crosses with different donor strains (Hfr C, Hfr 3.0SO, F' W1655) and in their sensitivity to UV and gamma-rays. It is concluded that all UVr revertants are rec A+ and carried mutations either in the same recA gene (true reversion or intragenic suppression) or in genes closely linked with recA.