Mammalian Growth Hormone-Releasing Hormone Indirectly Stimulates Sex Steroid Production in Tilapia     

Anita M.  Kelly Christopher C.  Kohler 《Journal of the World Aquaculture Society》2000,31(3):416-425

Abstract.— Fish possess a growth hormone similar to mammalian growth hormone, and the presence of a growth hormone-releasing hormone-like material in the brain has been demonstrated in several teleost species. We investigated the effect of a mammalian growth hormone-releasing hormone on serum estradiol-17β and testosterone concentrations in tilapia Oreochromis mossambicus and a hybrid O. niloticus × O aureus because growth hormone has been implicated in the regulation of gonadal functions in teleosts. Three hours after injecting the releasing hormone, male and female serum testosterone concentrations significantly increased compared to controls, while serum estradiol-17β concentrations increased significantly only in females. These increases were commensurate with respective serum steroid concentrations in fish injected with gonadotropin releasing-hormone. Studies utilizing hypophysectomized fish resulted in non-detectable levels of serum sex steroids in fish treated with the growth hormone-releasing hormone; however, significant increases occurred in fish treated with human chorionic gonadotropin. Similarly, gonadal tissue incubated with growth hormone releasing hormone had non-detectable levels of sex steroids in the media, whereas gonads incubated with human chorionic gonadotropin had significant increases in sex steroid concentrations. These studies suggest that growth hormone-releasing hormone acts at the level of the pituitary. Although mammalian growth hormones have been shown to increase serum gonadotropic hormone concentrations, this study provides evidence that a mammalian growth hormone-releasing hormone has the ability to indirectly increase sex steroid levels in fish.  相似文献   

Editorial     

Anita M. Ezzo 《Journal Of Agricultural & Food Information》2017,18(2):73-74

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Effects of Yucca shidigera Extract on Growth, Nitrogen Retention, Ammonia Excretion, and Toxicity in Channel Catfish Ictalurus punctatus and Hybrid Tilapia Oreochromis mossambicus × O. niloticus     

Anita M.  Kelly Christopher C.  Kohler 《Journal of the World Aquaculture Society》2003,34(2):156-161

Nitrogenous waste control in aquaculture systems is necessary to maintain healthy animals and to meet effluent standards. Decreased ammonia production has been attained in traditional livestock production systems by adding extracts of Yucca shidigera to the feed or storage lagoon system. An extract of Yucca shidigera was fed to post yolk-sac and juvenile channel catfish Ictalurus punctatus and hybrid tilapia Oreochrornis mossambicus × O. niloticus to determine the effects on growth, nitrogen retention, ammonia excretion, and toxicity. Post yolk-sac channel catfish fry fed the 1.0-g yucca extract/kg as an agar coating were the only group of experimental organisms that had significantly greater weight gains compared to the control and 0.5-g yucca extract/kg diet groups after 12 wk. Significantly lower fecal nitrogen concentrations were obtained from catfish fed diets containing yucca extract compared to the control groups, although no differences between fecal nitrogen concentrations for catfish fed diets with either 0.5-g or 1.0-g yucca extract/kg diet occurred. Ammonia excretion rates were significantly lower for catfish fed diets containing yucca extract compared to the control group. Accordingly, fish fed diets containing the yucca extract had significantly greater whole-body protein composition, while lipid levels were significantly lower. No significant differences in proximate composition occurred for fish fed any of the diets containing yucca extract, though growth rates were significantly higher than the controls. This study demonstrated that a yucca extract can be used in the diet of channel catfish, and increased growth and decreased ammonia concentrations can be obtained in rearing systems.  相似文献   

Genetic basis of seedling-resistance to leaf rust in bread wheat 'Thatcher'   总被引：1，自引：0，他引：1  

A. N. Mishra    K. Kaushal    G. S. Shirsekar    S. R. Yadav    R. N. Brahma    H. N. Pandey 《Plant Breeding》2005,124(5):514-516

The bread wheat cultivar ‘Thatcher’ is documented to carry the gene Lr22b for adult‐plant resistance to leaf rust. Seedling‐resistance to leaf rust caused by Puccinia triticina in the bread wheat cultivar ‘Thatcher’, the background parent of the near‐isogenic lines for leaf rust resistance genes in wheat, is rare and no published information could be found on its genetic basis. The F₂ and F₃ analysis of the cross ‘Agra Local’ (susceptible) × ‘Thatcher’ showed that an apparently incompletely dominant gene conditioned seedling‐resistance in ‘Thatcher’ to the three ‘Thatcher’‐avirulent Indian leaf rust pathotypes – 0R8, 0R8‐1 and 0R9. Test of allelism revealed that this gene (temporarily designated LrKr1) was derived from ‘Kanred’, one of the parents of ‘Thatcher’. Absence of any susceptible F₂ segregants in a ‘Thatcher’ × ‘Marquis’ cross confirmed that an additional gene (temporarily designated LrMq1) derived from ‘Marquis’, another parent of ‘Thatcher’, was effective against pathotype 0R9 alone. These two genes as well as a second gene in ‘Kanred’ (temporarily designated LrKr2), which was effective against all the three pathotypes, but has not been inherited by ‘Thatcher’, seem to be novel, undocumented leaf rust resistance genes.  相似文献   

Identification of RAPD markers linked to the rust (<Emphasis Type="Italic">Uromyces fabae</Emphasis>) resistance gene in pea (<Emphasis Type="Italic">Pisum sativum</Emphasis>)     

S.?Vijayalakshmi  Kusum?Yadav  Chanda?Kushwaha  S.?B.?Sarode  C.?P.?Srivastava  Ramesh?Chand  B.?D.?SinghEmail author 《Euphytica》2005,144(3):265-274

Summary Two RAPD markers linked to gene for resistance (assayed as pustule number cm⁻² leaf area) to rust [Uromyces fabae (Pers.) de Bary] in pea (Pisum sativum L.) were identified using a mapping population of 31 BC₁F₁ [HUVP 1 (HUVP 1 × FC 1] plants, FC 1 being the resistant parent. The analysis of genetics of rust resistance was based on the parents, F₁, F₂, BC₁F₁ and BC₁F₂ generations. Rust resistance in pea is of non-hypersensitive type; it appeared to be governed by a single partially dominant gene for which symbol Ruf is proposed. Further, this trait seems to be affected by some polygenes in addition to the proposed oligogene Ruf. A total of 614 decamer primers were used to survey the parental polymorphism with regard to DNA amplification by polymerase chain reaction. The primers that amplified polymorphic bands present in the resistant parent (FC 1) were used for bulked segregant analysis. Those markers that amplified consistently and differentially in the resistant and susceptible bulks were separately tested with the 31 BC₁F₁ individuals. Two RAPD makers, viz., SC10-82₃₆₀ (primer, GCCGTGAAGT), and SCRI-71₁₀₀₀ (primer, GTGGCGTAGT), flanking the rust resistance gene (Ruf) with a distance of 10.8 cM (0.097 rF and LOD of 5.05) and 24.5 cM (0.194 rF and a LOD of 2.72), respectively, were identified. These RAPD markers were not close enough to Ruf to allow a dependable maker-assisted selection for rust resistance. However, if the two makers flanking Ruf were used together, the effectiveness of MAS would be improved considerably.  相似文献   

A leaf rust resistance gene, different from Lr34, associated with leaf tip necrosis in wheat     

A. N. Mishra    K. Kaushal    S. R. Yadav    G. S. Shirsekar    H. N. Pandey 《Plant Breeding》2005,124(5):517-519

The gene Lr34 has contributed to durable resistance to leaf rust caused by Puccinia triticina in wheat worldwide. The closely associated leaf tip necrosis is generally used as the gene's marker. Lr34 has been postulated in many Indian bread wheat cultivars including ‘C 306’, based on the associated leaf tip necrosis and a few other field and glasshouse observations. The present study showed monogenic control of adult‐plant resistance in ‘C 306’ to leaf rust pathotype 77‐5 (121R63‐1). The F₂ segregation in the crosses between ‘C 306’ and the two known carriers of Lr34, ‘Line 897’ and ‘Jupateco 73’‘R’ fitted a digenic ratio. The F₃ families derived from the susceptible F₂ segregants were true breeding for susceptibility, proving the absence of Lr34 in ‘C 306’. The cross between ‘Line 897’ and ‘Jupateco 73’‘R’ did not segregate for susceptibility. Resistance in the cross ‘Agra Local’ (susceptible) × ‘C 306’ was associated with leaf tip necrosis, showing that the leaf rust resistance gene in ‘C 306’ was associated with leaf tip necrosis, but was different from Lr34. This gene is being temporarily designated as Lr‘C 306’. Hence, leaf tip necrosis cannot be considered as an exclusive marker for selecting Lr34 in wheat improvement.  相似文献   

Performance of pearl millet isonuclear hybrids involving different cytoplasmic male-sterility systems     

O. P. Yadav 《Plant Breeding》1996,115(2):140-142

The performance of pearl millet hybrids involving four sources of cytoplasmic male sterility (CMS), including the most-exploited A₁ source, was compared to evaluate the effects of cytoplasm on grain yield. The mean grain yield of hybrids possessing A₂, A₃ and A₄ cytoplasms was either similar to or significantly higher than that of their counterpart hybrids with A₁ cytoplasm. Hybrids based on A₃ and A₄ cytoplasms produced, on average, 8% more grain compared with those based on A₁ cytoplasm. This suggested that these CMS sources could be used as alternatives to A₁ cytoplasm to widen the cytoplasmic base of hybrids. The results indicated that most of the variation in hybrids was accounted for by pollinator and cytoplasm × pollinator interactions, suggesting the use of genetically diverse pollinators in pearl millet hybrid breeding.  相似文献   

Influence of cyto‐sterility sources of female line on seed quality of Indian mustard (Brassica juncea L. Czern & Coss.) in relation to storage period          下载免费PDF全文

Shyamal Kumar Chakrabarty  Aniruddha Maity  Jung Bahadur Yadav 《Plant Breeding》2015,134(3):333-337

Effect of cyto‐sterility sources on morphology and yield attributes in F₁ has well been studied in different crops, but not on the seed quality of hybrid. Six cytoplasmic male sterile (CMS) lines, viz. Ogura, Siifolia, Erucoides, Moricandia, Tournefortii and Oxyrrhina, which represent six different sources of CMS, were pollinated by a single maintainer line (‘Pusa Bold’) to check whether CMS sources have any marked effect on seed quality. Seeds were collected in 2007–2008 (rabi season: October–April) from CMS maintenance plot and kept in ambient storage for next 3 years. The results indicated that CMS/cyto‐sterility sources influenced the seed quality parameters in fresh seed as well as after storage. Per cent germination (as means over the storage period) was recorded up to 89.00, 88.25 and 87.88 in Moricandia, Ogura and Oxyrrhina systems, respectively, and it was significantly different from Tournefortii and ‘Pusa Bold’ (70.13 and 74.38, respectively). The CMS sources also had pronounced effect on other seed quality traits, viz. root and shoot length and seedling dry matter, and Ogura and Moricandia (green) performed better.  相似文献   

Marker assisted accelerated introgression of null allele of kunitz trypsin inhibitor in soybean     

Vineet Kumar  Anita Rani  Reena Rawal  Vaishali Mourya 《Breeding Science》2015,65(5):447-452

Development of kunitz trypsin inhibitor (KTI)-free soybean is crucial for soy-food industry as the heat inactivation employed to inactivate the anti-nutritional factor in regular soybean incurs extra cost and affects protein solubility. In the presented work, a null allele of KTI from PI542044 was introgressed into cultivar ‘JS97-52’ (recurrent parent) through marker assisted backcrossing. Foreground selection in BC₁F₂, BC₂F₂ and BC₃F₂ was carried out using the null allele-specific marker in tandem with SSR marker Satt228, tightly linked with a trypsin inhibitor Ti locus. Background selection in null allele-carrying plants through 106 polymorphic SSR markers across the genome led to the identification of 9 KTI-free lines exhibiting 98.6% average recurrent parent genome content (RPGC) after three backcrosses, which otherwise had required 5–6 backcrosses through conventional method. Introgressed lines (ILs) were free from KTI and yielded at par with recurrent parent. Reduction of 68.8–83.5% in trypsin inhibitor content (TIC) in ILs compared to the recurrent parent (‘JS97-52’) was attributed to the elimination of KTI.  相似文献   

The linkage between the stem rust resistance gene Sr2 and pseudo-black chaff in wheat can be broken     

A. N. Mishra    K. Kaushal    S. R. Yadav    G. S. Shirsekar    H. N. Pandey 《Plant Breeding》2005,124(5):520-522

Recessively inherited gene Sr2 has provided the basis of durable resistance to stem rust (caused by Puccinia graminis tritici) in wheat (Triticum aestivum L.) worldwide. The associated earhead and stem melanism or ‘pseudo‐black chaff’ is generally used as a marker for this gene. Sr2 has been postulated in many wheat cultivars of India including ‘Lok 1’, based on associated pseudo‐black chaff in adult plants, and leaf chlorosis in seedlings. However, dominant inheritance of the resistance factor operating in ‘Lok 1’, and a 13 : 3 (resistant : susceptible) F₂ segregation in the ‘Sr2‐line’ (‘Chinese Spring’⁶ × ‘Hope’ 3B) × ‘Lok 1’ cross confirmed that Sr2 was absent in ‘Lok 1’. Susceptible plants with a pseudo‐black chaff phenotype were observed in F₂ populations of ‘Agra Local’ (susceptible) × ‘Lok 1’, and the ‘Sr2‐line’ × ‘Lok 1’ crosses. Most of the F₃ families derived from the susceptible F₂ segregants with pseudo‐black chaff phenotypes were true breeding for the expression of pseudo‐black chaff with susceptibility to stem rust. Thus, linkage of pseudo‐black chaff with Sr2 in wheat can be broken, and hence, caution may be exercised in using pseudo‐black chaff as a marker for selecting Sr2 in breeding programmes.  相似文献