The disappearing Dry Chaco,one of the last dry forest systems on earth     

de la Sancha  Noé U.  Boyle  Sarah A.  McIntyre  Nancy E.  Brooks  Daniel M.  Yanosky  Alberto  Cuellar Soto  Ericka  Mereles  Fatima  Camino  Micaela  Stevens  Richard D. 《Landscape Ecology》2021,36(10):2997-3012

Landscape Ecology - The Dry Chaco spans more than 87 million hectares across Argentina, Bolivia, and Paraguay. This unique forest system has experienced extensive loss and fragmentation due to...  相似文献   

Daily activity pattern of the marine shrimp Litopenaeus vannamei (Boone 1931) juveniles under laboratory conditions     

Cibele Soares Pontes  Maria de Fatima Arruda  Alexandre Augusto de Lara Menezes  & Patrícia Pereira de Lima 《Aquaculture Research》2006,37(10):1001-1006

Lack of information on the daily activity patterns of Litopenaeus vannamei (Boone 1931) might result in inadequate feed management strategies in shrimp farms. In order to provide information to improve feed management in shrimp farms, the daily activity of juvenile shrimp reared in glass aquaria was studied, using L. vannamei (7.57±1.01 g), equivalent to 33 shrimp m^?2. Thirty‐two shrimp were observed, half in light and half in dark phase, over 280 h in 15 min h^?1 windows. Feed was provided once a day, at 10% of tank biomass. Swimming, exploration of substrate, inactivity and cleaning were recorded through instantaneous focal sampling. During the dark phase, swimming was predominant and alternated with exploration. In the light phase, inactivity was predominant, and again alternated with exploration. Cleaning occurred evenly in both the light and the dark. Substrate exploration, which characterizes the search for food, occurred in both dark and light phases, with a most intense peak 7 h after light phase onset, indicating this as the optimal feed offer.  相似文献   

Molecular cytogenetics and flow cytometry reveal conserved genome organization in <Emphasis Type="Italic">Pinus mugo</Emphasis> and <Emphasis Type="Italic">P. uncinata</Emphasis>     

Faruk Bogunić  Sonja Siljak-Yakovlev  Edina Muratović  Fatima Pustahija  Safer Medjedović 《Annals of Forest Science》2011,68(1):179-187

• Introduction   

The most common representatives of the European mountain pine complex (Pinus mugo s.l.) are P. mugo s.s. and Pinus uncinata.  相似文献   

A 50-year record of quinolone and sulphonamide antimicrobial agents in Seine River sediments     

Fatima Tamtam  Barbara Le Bot  Tuc Dinh  Sophie Mompelat  Joelle Eurin  Marc Chevreuil  Philippe Bonté  Jean-Marie Mouchel  Sophie Ayrault 《Journal of Soils and Sediments》2011,11(5):852-859

Purpose  

Even though sediments may represent a reservoir for antimicrobial agents, little is known about the persistence of these molecules over time or their accumulation. In this study, six antimicrobial agents, oxolinic acid, flumequine, nalidixic acid, norfloxacin, sulphamethoxazole and trimethoprim, were investigated in a sediment core from the Seine River. This work aimed to (1) measure antimicrobial agent contamination levels in the sediment and identify their origins, (2) obtain information on the persistence of these compounds in sediment over long periods (>4 years) and (3) show the existence of a historical record in sediment of river contamination by antimicrobial agents.  相似文献   

A serological study of Babesia caballi and Theileria equi in Thoroughbreds in Trinidad     

Asgarali Z  Coombs DK  Mohammed F  Campbell MD  Caesar E 《Veterinary parasitology》2007,144(1-2):167-171

Ninety-three (93) horses were investigated for serum antibodies to Theileria equi (T. equi) and Babesia caballi (B. caballi) using the immunofluorescent antibody test (IFAT). Seventy-seven (82.8%) horses were seropositive; 31 (33.3%) were positive to T. equi compared to 64 (68.8%) to B. caballi while 18 (19.4%) horses were seropositive to both parasites. No significant differences in antibody frequencies among females and males for either T. equi or B. caballi were noted. Differences in seropositivity to B. caballi among age groups were not significant. Antibodies to T. equi were more frequent than to B.caballi in the age group 5 years and over than in the 1-2 and 2-4 years age groups (p<0.05). Unlike T. equi antibodies, B. caballi antibodies in horses in the county of Caroni were significantly less frequent when compared to other counties (p<0.05). Of 18 (19.4%) clinically ill horses, seven (42.9%) had clinicopathological evidence of anemia. Only one-third (6 of 18) horses were positive for the parasite on Wright-Giemsa stained blood smears and anemia was present in only 2. We report here that B. caballi and not T. equi may be the more common agent of piroplasmosis in Trinidad.  相似文献   

Symbiotic efficiency and identification of rhizobia that nodulate cowpea in a Rhodic Eutrudox     

Márcia Rufini  Michele Aparecida Pereira da Silva  Paulo Ademar Avelar Ferreira  Alice de Souza Cassetari  Bruno Lima Soares  Messias José Bastos de Andrade  Fatima Maria de Souza Moreira 《Biology and Fertility of Soils》2014,50(1):115-122

Cowpea (Vigna unguiculata (L.) Walp.) is one of the most important crops in the north and northeast regions of Brazil, where it is grown under the subsistence regime, mainly because of its adaptation to the local edaphoclimatic conditions. This species is an important legume in Brazil because of its significant nutritional value in the diet of low-income populations. Moreover, it is able to benefit from the process of biological nitrogen fixation, which leads to a significant reduction in production costs. The objective of this research was to evaluate the agronomic efficiency of bacterial strains approved by the Ministry of Agriculture, Livestock and Supply for commercial inoculant production when in symbiosis with cowpea in a Rhodic Eutrudox in Lavras, MG, as well as to identify and verify the efficiency of the native populations that nodulate cowpea. Agronomic efficiency of nitrogen-fixing nodulating bacterial strains (UFLA 03-84, INPA 03-11B, and BR 3267) in symbiosis with cowpea was evaluated in the field. Subsequently, the efficiency and diversity of isolates from the nodules obtained in the field were evaluated under greenhouse conditions. The genetic diversity of the efficient isolates was determined by partial sequencing of the 16S rRNA gene. Grain yields obtained by the inoculation of seeds in the field with the strains were similar to those of the controls without inoculation with and without mineral N addition indicating the existence of efficient native populations. In the native community, we identified isolates with similar or higher efficiency than the strains approved for cowpea inoculation and the control that received mineral N. The isolates subjected to partial sequencing of the 16S rRNA gene were phylogenetically related to the Bradyrhizobium genus.  相似文献   

Indirect effects of experimental warming on dissolved organic carbon content in subsurface peat     

Frédéric Delarue  Sébastien Gogo  Alexandre Buttler  Luca Bragazza  Vincent E. J. Jassey  Grégory Bernard  Fatima Laggoun-Défarge 《Journal of Soils and Sediments》2014,14(11):1800-1805

Purpose

The peatland carbon store is threatened by climate change and is expected to provide positive feedback on air temperature. Most studies indicate that enhanced temperature and microbial activities result in a rise of dissolved organic carbon (DOC) as a consequence of higher peat decomposition. Few of them, however, have investigated the impact of in situ experimental warming on DOC response.

Material and methods

We studied the response of DOC, dissolved organic nitrogen (DON), phenol oxidase, and fluorescein diacetate activities (FDA) to a 3-year in situ experimental warming using open-top chambers (OTCs) in a Sphagnum-dominated peatland.

Results and discussion

No significant warming of soil was recorded, implying that the simultaneous decrease in DOC and DON and the rise in FDA at the depths of 25 and 40 cm were not caused by the direct effect of OTCs on water temperature, but might instead have been mediated by plant root exudates. The water chemistry suggests that DOC production was compensated by in situ mineralization. We hypothesize that an increased hydrolysis of organic matter (OM) was counterbalanced by the mineralization of dissolved organic matter (DOM) and that microorganisms preferentially used labile compounds originating from increased root exudates.

Conclusions

This trade-off between production of DOC through hydrolysis and consumption in the process of mineralization shows (1) the limitation of using only DOC as an indicator of the sensitivity of peat decomposition to climate warming and (2) the need to improve our understanding of the indirect impact of root exudates.  相似文献   

Recent Insights into Signaling Responses to Cope Drought Stress in Rice   总被引：1，自引：0，他引：1  

Muhammad Mahran Aslam  Muhammad Abdul Rehman Rashid  Mohammad Aquil Siddiqui  Muhammad Tahir Khan  Fozia Farhat  Shafquat Yasmeen  Imtiaz Ahmad Khan  Shameem Raja  Fatima Rasool  Mahboob Ali Sial  Zhao Yan 《水稻科学》2022,29(2):105-117

  相似文献   

Influence of native endophytic bacteria on the growth and bacterial crown rot tolerance of papaya (Carica papaya)     

Rivarez  Mark Paul Selda  Parac  Elizabeth P.  Dimasingkil  Shajara Fatima M.  Magdalita  Pablito M. 《European journal of plant pathology / European Foundation for Plant Pathology》2021,161(3):593-606

The native plant microbiome is composed of diverse microbial communities that influence overall plant health, with some species known to promote plant growth and pathogen resistance. Here, we show the antibacterial and growth promoting activities of autoclaved culture metabolites (ACM) from native endophytic bacteria (NEB). These NEB were isolated from a papaya cultivar (var. Cariflora) that is tolerant to bacterial crown rot (BCR) caused by Erwinia mallotivora. In this cultivar, bacterial colonization in tissues recovering from the disease was observed before onset of tissue regeneration or ‘regrowth’. We further isolated and characterized these bacteria and were able to identify two culturable stem NEB related to plant endophytic genera Kosakonia sp. (ex. Enterobacter sp., isolate EBW), and to Sphingomonas sp. (isolate EBY). We also identified root NEB under genus Bacillus (isolates BN, BS, and BT). Inhibition assays indicated that ACM from these NEB promptly (within 18-30 h) and efficiently inhibited (60–65% reduction) E. mallotivora proliferation in vitro. When surface-sterilized papaya seeds were soaked in ACM from isolates EBY and EBW, germination was variably retarded (20–60% reduction) depending on plant genotype, but plant biomass accumulation was significantly stimulated, at around two-fold increase. Moreover, greenhouse experiments show that ACM from all isolates, especially isolate EBW, significantly reduced BCR incidence and severity in a susceptible genotype (var. Solo), at around two-fold. In general, our observations of pathogen antagonism and plant growth promotion leading to disease reduction, suggested the influence of native endophytic bacteria to increased fitness in plants, and tolerance against the re-emerging crown rot disease of papaya.

  相似文献   

Anti-oxidant enzyme responses during in vitro embryogenesis in Catharanthus roseus     

S. Fatima  J. Samaj 《The Journal of Horticultural Science and Biotechnology》2013,88(6):569-574

Summary

The present study was carried out to analyse the activities of several anti-oxidant enzymes at various stages of somatic embryogenesis in Catharanthus roseus. The hypothesis was that anti-oxidant enzymes accumulated as part of a cellular defence mechanism in response to stress. We therefore measured superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities in various in vitro-grown tissues such as embryogenic and non-embryogenic calli, and in embryos at various stages. SOD activity increased gradually from the early embryogenic stage to heart-shaped stage embryos, but declined in the later stages (i.e., torpedo-shaped and cotyledonary embryos). In contrast, APX activity was high in non-embryogenic callus and decreased rapidly during the stage of embryo initiation. This pattern was the same for CAT. The maximum CAT activity was observed in non-embryogenic callus, then it declined almost linearly at the embryonic and post-embryonic developmental stages. The effect of exogenous hydrogen peroxide (H₂O₂) on in vitro embryogenesis was also evaluated. Lower H₂O₂ levels (0.025 mM) promoted embryo formation, whereas higher levels (0.10 mM) inhibited embryogenesis in C. roseus. Finally, higher soluble protein, free amino acid, and proline contents were found in embryogenic calli compared to non-embryogenic calli.  相似文献