Effects of Neem Seed Derivatives on Brown Planthopper Symbiotes     

S. Raguraman  R. C. Saxena 《Phytoparasitica》1994,22(4):299-307

Populations of intracellular symbiotes declined significantly in brachypterous females of the brown planthopper,Nilaparvata lugens (Stål), which were stressed during nymphal development by caging them on IR20 rice plants treated with 3% neem oil, 5% neem seed kernel aqueous extract, or 10% neem cake aqueous extract. In addition, nymphs grew poorly and symbiote populations in prospective females declined, when reared on rice plants grown in soil treated with neem cake; this indicates systemic action of bioac-tive neem constituents. Addition of custard-apple oil to neem oil did not enhance the inhibitory effects. The effects of neem derivatives on the symbiotes may be either host-mediated — possibly through disturbed neuroendocrine homeostasis, or direct — leading to perturbations of host-symbiote equilibrium.  相似文献   

Studies on effects of certain quinones: III. Photosynthetic 14CO2 incorporation by Rhodospirillum rubrum     

J. Saxena  H.C. Sikka  G. Zweig 《Pesticide biochemistry and physiology》1975,5(2):189-195

Substituted naphthoquinones, 2,3,-dichloro-1,4-naphthoquinone, and 2-methyl-1,4-naphthoquinone produced marked changes in the pattern of ¹⁴C-distribution during ¹⁴CO₂-fixation by photosynthetic bacterium Rhodospirillum rubrum. The most obvious change in the labeling pattern during photoautotrophic ¹⁴CO₂-fixation was a several-fold increase in 3-phosphoglyceric acid accompanied with a decrease in the amount of glutamate. In photoheterotrophic cells, quinones caused an appreciable increase in ¹⁴C-glycolic acid and concomitant decrease, although not proportional, in the amount of ¹⁴C-sugar phosphate. The level of ¹⁴C-incorporated in poly-β-hydroxybutyrate and ether-extractable lipids was considerably decreased in photoautotrophic and photoheterotrophic cells treated with quinones. The ability of quinones to interfere with the synthesis of NADH and ATP, and their ability to interact with sulfhydryl enzymes and coenzymes appears to be responsible for the changes observed.  相似文献   

Characterisation of caecum and crop microbiota of Indian indigenous chicken targeting multiple hypervariable regions within 16S rRNA gene     

S. Saxena  S. Tomar  D. Sapcota  G. Gonmei 《British poultry science》2016,57(3):381-389

1. A comparative analysis of caecum and crop microbiota of chick, grower and adult stages of Indian indigenous chickens was conducted to investigate the role of the microbiota of the gastrointestinal tract, which play an important role in host performance, health and immunity.

2. High-throughput Illumina sequencing was performed for V3, V4 and V4-V6 hypervariable regions of the 16S rRNA gene. M5RNA and M5NR databases under MG-RAST were used for metagenomic datasets annotation.

3. In the crop, Firmicutes (~78%) and Proteobacteria (~16%) were the predominant phyla whereas in the caecum, Firmicutes (~50%), Bacteroidetes (~29%) and Actinobacteria (~10%) were predominant. The Shannon-Wiener diversity index suggested that sample richness and diversity increased as the chicken aged.

4. For the first time, the presence of Lactobacillus species such as L. frumenti, L. antri, L. mucosae in the chicken crop along with Kineococcus radiotolerans, Desulfohalobium retbaense and L. jensenii in the caecum are reported. Many of these bacterial species have been found to be involved in immune response modulation and disease prevention in pigs and humans. The gut microbiome of the indigenous chicken was enriched with microbes having probiotic potential which might be essential for their adaptability.

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Outbreaks of proliferative haemorrhagic enteropathy on two pig farms   总被引：2，自引：0，他引：2  

PK HOLYOAKE  RS CUTLER 《Australian veterinary journal》1995,72(7):253-256

SUMMARY Clinical signs of proliferative haemorrhagic enteropathy (PHE) including anaemia, dysentery and sudden death were observed in finisher pigs and young breeding stock on 2 farms. On farm A, PHE occurred 12 months after repopulation of the farm. Other outbreaks of PHE occurred after the withdrawal of therapeutic concentrations of in-feed antibacterial agents (farm A), or after monensin sodium (100 g/t) replaced olaquindox (100 g/t) in feed (farm B). The outbreaks, the possible sources of contamination and the role of antibacterial feed additives in the treatment and control of PHE are described.  相似文献   

Effect of certain substituted naphthoquinones on growth and respiration of Rhodospirillum rubrum     

J. Saxena  H.C. Sikka  G. Zweig 《Pesticide biochemistry and physiology》1973,3(1):66-72

The effect of dichlone (2,3-dichloro-1,4-naphthoquinone) on photoautotrophic, photoheterotrophic and heterotrophic growth, and respiration of Rhodospirillum rubrum (a nonsulfur purple bacterium) was studied to elucidate the mechanism of action of this toxicant on photosynthetic bacteria. The photosynthetic growth with malate or with hydrogen and CO₂ was inhibited by dichlone. Light respiration of photoheterotrophically grown cells, unlike their dark respiration, was found to be insensitive to dichlone. Although dichlone caused an inhibition of the respiration of dark-grown cells, such cells were able to grow in the presence of dichlone after a lag. Light-dependent ¹⁴C-substrate incorporation by photoheterotrophic or photoautotrophic cells was found to be relatively more sensitive to dichlone than oxidative substrate incorporation by heterotrophic cells. Short-term exposure of the light-grown cells to dichlone resulted in an irreparable loss of their ability to grow photosynthetically and photoassimilate ¹⁴C-substrates. Menadione (2-methyl-1,4-naphthoquinone), a synthetic vitamin K, failed to affect these reactions to a significant extent at comparable concentrations. The findings suggest that dichlone causes an irreversible damage to some primary photosynthetic reaction in chromatophores, whereas the damage caused to the dark heterotrophic metabolism of the cell is less severe and repairable. The inhibitory action of dichlone does not appear to be via the formation of semiquinone free radicals.  相似文献   

Excision arthropathy of the hip in buffalo calves. A preliminary report     

S Sahu  R Singh  O P Saxena  B N Bhargava 《The Indian veterinary journal》1970,47(5):426-429

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Path coefficient analysis of correlation between breeding cycles of the common myna Acridotheres tristis (Passeriformes: Sturnidae) and its phthirapteran ectoparasites     

Srivastava R  Kumar S  Gupta N  Singh SK  Saxena AK 《Folia parasitologica》2003,50(4):315-316

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Effect of immunization with bovine luteinizing hormone receptor on ovarian function in cats     

Saxena BB  Clavio A  Singh M  Rathnam P  Bukharovich EY  Reimers TJ  Saxena A  Perkins S 《American journal of veterinary research》2003,64(3):292-298

OBJECTIVE: To determine the effect of immunization with bovine luteinizing hormone receptor (LH-R) on ovarian function of cats. ANIMALS: 9 adult female domestic cats. PROCEDURE: 7 cats were immunized with 0.5 mg of LH-R encapsulated in a silastic subdermal implant (3 x 10 mm); 2 served as control cats. Receptors had 80% specific binding to 125I-human chorionic gonadotropin with a binding capacity of 2,682 pM/mg. Cats received booster injections of LH-R. Cats were induced to ovulate with luteinizing hormone (LH) releasing hormone on day 345. Samples of venous blood and vaginal cells were collected through day 395. Observation of estrus behavior continued until day 516. Serum concentrations of estradiol, progesterone, thyroid gland hormones, LH, and LH-R antibody were determined. RESULTS: LH-R antibody was detected in the sera of immunized cats within 21 days after implantation. Detection of LH-R antibody was associated with suppression of serum progesterone to < or = 0.5 ng/mL during the study period, compared with concentrations of 5 to 10 ng/mL in control cats. Immunized cats did not display signs of estrus. Release of LH after administration of LH-releasing hormone indicated an intact hypothalamic-pituitary axis but poor corpus luteum function. Serum estradiol concentrations remained between 30 to 40 pg/mL in immunized and control cats. With the decrease antibody titers, hormone concentrations returned to a pattern consistent with that during fertility. CONCLUSIONS AND CLINICAL RELEVANCE: Active immunization with LH-R suppressed corpus luteum function in cats. The effect was reversible. An LH-R-based antifertility vaccine may have clinical application in other vertebrates.  相似文献   

Chemical Manipulation of Reproductive Efficiency of Chickpea (Cicer arietinnum L.) by Triadimefon in Relation to Changes in Ethylene     

D. C. Saxena  S. Abbas  R. K. Sairam 《Journal of Agronomy and Crop Science》2000,185(1):27-32

Reproductive efficiency was successfully manipulated by the application of different concentrations of triadimefon at pre‐flowering, flowering and post‐flowering stages in chickpea (Cicer arietinum L.). Triadimefon improved the parameters determining reproductive efficiency. Yield was significantly improved due to reductions in flower and pod abscission by the application of triadimefon, which also lowered the ethylene levels in leaves, flowers and pods and delayed senescence. These findings suggest a relationship between ethylene level and reproductive efficiency in chickpea. Further, they indicate that triadimefon can be used for chemical manipulation of the reproductive efficiency of chickpea under field conditions.  相似文献   

Interactive Effects of Salinity and Biological Nitrogen Fixation on Chickpea (Cicer arietinum L.) Growth     

R. Zurayk  M. Adlan  R. Baalbaki  M. C. Saxena 《Journal of Agronomy and Crop Science》1998,180(4):249-258

The effect of salinity on the nodulation, N-fixation and plant growth of selected chickpea- Rhizobium symbionts was studied- Eighteen chickpea rhizobial strains were evaluated for their growth in a broth culture at salinity levels of 0 to 20 dS m⁻¹ of NaCl + Na₂SO₄. Variability in response was high. Salinity generally reduced the lag phase and/or slowed the log phase of multiplication of Rhizobium. Nine chickpea genotypes were also evaluated for salt tolerance during germination and early seedling growth in Petri dishes at five salinity levels (0–32 dS m⁻¹). Chickpea genotypes ILC-205 and ILC-1919 were the most salt-tolerant genotypes. The selected rhizobial strains and chickpea cultivars were combined in a pot experiment aimed at investigating the interactive effect of salinity (3, 6 and 9 dS m⁻¹) and N source (symbiosis vs. inorganic N) on plant growth. Symbiotic plants were more sensitive to salinity than plants fed mineral N. Significant reductions in nodule dry weight (59.8 %) and N fixation (63.5 %) were evident even at the lowest salinity level of 3 dS m-¹. Although nodules were observed in inoculated plants grown at 6 dS m-¹, N-fixation was completely inhibited. The findings indicate that symbiosis is more salt-sensitive than both Rhizobium and the host plant, probably due to a breakdown in one of the processes involved in symbiotic-N fixation. Improvement of salinity tolerance in field grown chickpea may be achieved by application of sufficient amounts of mineral nitrogen.  相似文献