Flood control,drainage and irrigation projects in Bangladesh and their impact on soils: an empirical study     

M. J. Alexander  M. S. Rashid  S. D. Shamsuddin  M. S. Alam 《Land Degradation \u0026amp; Development》1998,9(3):233-246

The combination of a rising population and increased food demand has placed tremendous pressure on the land resources of Bangladesh. These pressures are exacerbated by the annual wet-season floods which frequently devastate much of the agricultural land. Successive governments have therefore sought international aid to assist in the development of flood control measures. Of particular importance are 14 major schemes which aim to provide protection from 20–25 year return floods by the construction of earth-embanked enclosures. There is no doubt that these schemes have been very successful in protecting valuable agricultural areas from floods and hence increasing agricultural production. There is, however, growing evidence from a range of sources for long-term deterioration in soil fertility within the project areas. The study reported here is the first to systematically examine the changes taking place in soil properties following the establishment of a flood control, drainage and irrigation project. Comparison of two soil series, sampled from within and without the project area, demonstrate that within six years of project establishment, significant adverse changes have occurred in several soil properties; these include increasing acidity and a decline in available nutrients. The changes are attributable to a combination of poor management strategies and the absence of the annual flood input of silt. As Bangladesh cannot afford any decline in agricultural output, it is vital to establish whether adverse changes recorded here are occurring in other projects. This can be achieved by the establishment of a nationwide programme of soil fertility monitoring. © 1998 John Wiley & Sons, Ltd.  相似文献   

Prevalence of white spot syndrome virus infection detected by one-step and nested PCR in selected tiger shrimp (<Emphasis Type="Italic">Penaeus monodon</Emphasis>) hatcheries     

Farhana Ayub  Md. Yusuf Sarker  Md. Samsul Alam 《Aquaculture International》2008,16(5):405-415

White spot syndrome (WSS) is considered as a great threat to commercial farming of the tiger shrimp (Penaeus monodon). The causal agent of WSS is a DNA virus called white spot syndrome virus (WSSV). The prevalence of this dreadful virus infection has been studied in five randomly selected hatcheries located in the Cox’s Bazar district of Bangladesh. Both one-step and nested polymerase chain reaction (PCR) involving two pairs of primers, namely, 146F1/146R1 and 146F2/146R2, amplifying the 1447 bp and 941 bp fragments, respectively, were conducted to detect the WSSV. Out of 60 randomly collected shrimps, 12 (20%) were found to be positive by one-step PCR, while 18 (30%) were found to be positive by nested PCR. The nested PCR was found to be much more sensitive than the one-step PCR. The shrimp specimens showing clinical signs of WSS were positive for WSSV by both one-step and nested PCR. Some of the apparently healthy samples were also found to be positive for WSSV by nested PCR. Among the two primer-pairs, the inner pair amplifying the 941 bp fragment was more sensitive than the outer primer pair amplifying the 1447 bp fragment when used in one-step PCR.  相似文献   

Incidence, Endocrinology, Vascularity, and Morphology of Hemorrhagic Anovulatory Follicles in Mares   总被引：3，自引：2，他引：1  

O.J. Ginther VMD  PhD  E.L. Gastal DVM  PhD  M.O. Gastal DVM  PhD  M.A. Beg DVM  PhD 《Journal of Equine Veterinary Science》2007,27(3):130-139

The incidence of hemorrhagic anovulatory follicles (HAFs) is approximately 5% and 20% of estrous cycles during the early and late ovulatory season, respectively. The structures are more common in old mares (eg, >20 years), tend to occur repeatedly in individuals, and occur most frequently during the late follicular phase. In a recent study, the day of ovulation in controls and the first day of HAF formation, as indicated by cloudiness of follicular fluid, were defined as day 0. On day -1, future ovulating and HAF groups did not differ in follicle diameter or in the frequency of discrete gray-scale ultrasonic indicators of impending ovulation; however, in future HAFs, a greater percentage of the circumference of the follicle exhibited color-Doppler signals of blood flow. No differences were found between the two groups in systemic concentrations of progesterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) on days -4 to 2, but estradiol was elevated in the HAF group on day -3. The wall of the HAFs developed well-vascularized luteal tissue as indicated by echotexture and color Doppler signals and by the production of near normal levels of progesterone. In conclusion, HAFs formed from viable preovulatory follicles that did not differ from ovulatory follicles in diameter or gray-scale echotexture. Estradiol concentrations were elevated a few days before the failure of ovulation, and the wall of the follicle was more extensively vascularized on day -1.  相似文献   

Phytochemical study of Salvia moorcroftiana.     

V U Ahmad  Z Ali  M Zahid  N Alam  N Saba  T Khan  M Qaisar  M Nisar 《Fitoterapia》2000,71(1):84-85

Four known flavonoids were isolated from the aerial parts of Salvia moorcroftiana.  相似文献   

Application de la chromatographie en phase gazeuse au dosage du squalène dans les végétaux     

J. Brossard  S. Q. Alam  G. Mackinney 《Plant foods for human nutrition (Dordrecht, Netherlands)》1964,11(2-4):403-406

Résumé Découvert il y a plus de 50 ans, dans des huiles de foies de squaloides, le squalène C₃₀ H₅₀ a été ensuite identifié et dosé dans plusieurs huiles d'origine végétale.Les auteurs décrivent une nouvelle méthode de dosage, plus spécifique et plus sensible, par chromatographie en phase gazeuse et déshydrogenation de la fraction insaponifiable de végétaux.Les teneurs sont, en mg pour 100 g, d'environ 150 pour l'huile d'olive, 4 pour les feuilles d'olivier, 2 pour la luzerne, 0,1 pour les feuilles de sureau, acanthe, laitue et les feuilles et racines de carottes.

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Summary Discovered more than 50 years ago in liver oils of squaloids, squalene C₃₀ H₅₀ was later identified and determined in several oils of vegetable origin.The authors describe a new, more specific, and more sensitive, method of determination by gas chromatography and dehydrogenation of the unsaponiüable fraction of plants.The contents are, in mg per 100 g, about 150 for olive oil, 4 for olive-tree leaves, 2 for alfalfa, 0.1 for the leaves of elder, acanthus, lettuce, and leaves and roots of carrots.

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Zusammenfassung Vor mehr als 50 Jahren im Lebertran von Haifischen entdeckt, wurde das Squalen später in mehreren Ölen pflanzlichen Ursprungs identifiziert und bestimmt.Die Verfasser beschreiben eine neue mehr spezifische und empfindliche Bestimmungsmethode mittels Gaschromatographie und Dehydrogenierung der unverseifbaren Fraktion der Pflanzen.Die Gehalte sind, in mg/100 g, ungefähr 150 für Olivenöl, 4 für die Blätter des Ölbaumes, 2 für Klee, 0,1 für die Blätter des Hollunders, für Bärenklau, für Kopfsalat sowie für Blätter und Wurzeln der Möhren.

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avec 1 fig.  相似文献   

Nucleotide sequencing, whitefly transmission, and screening tomato for resistance against two newly described begomoviruses in bangladesh     

Maruthi MN  Alam SN  Kader KA  Rekha AR  Cork A  Colvin J 《Phytopathology》2005,95(12):1472-1481

ABSTRACT The molecular diversity of Tomato leaf curl viruses (ToLCVs), from the two main tomato growing areas of Jessore and Joydebpur, Bangladesh, was investigated. The viral DNA was amplified from tomato plants exhibiting mild and severe symptoms by polymerase chain reaction, and the complete genomes of the ToLCVs were sequenced. An isolate of the bipartite Tomato leaf curl New Delhi virus-Severe (ToLCNDV-Svr) was associated with the severe symptom phenotype from Jessore (ToLCNDV-Svr[Jes]). A previously undescribed monopartite virus, designated Tomato leaf curl Joydebpur virus-Mild (ToLCJV-Mld), was sequenced from plants showing mild symptoms. ToLCNDV-Svr[Jes] was most closely related to ToLCNDV-[Lucknow] at 95.7% nucleotide (nt) identity and Tomato leaf curl Gujarat virus-[Varanasi] at 90.6% nt identity, based on DNA-A and -B component sequences. ToLCJV-Mld was similar to Pepper leaf curl Bangladesh virus at 87.1% DNA-A nt identity. Identification of ToLCNDV-Svr[Jes] and ToLCJV-Mld was in addition to the previously described Tomato leaf curl Bangladesh virus, with which they shared 73.2 and 86.0% DNA-A nt identities, thus demonstrating the existence of at least three distinct viruses infecting tomato in Bangladesh. Nucleotide identities and placement in phylogenetic trees suggested that the three ToLCVs may have had different evolutionary pathways. The whitefly, Bemisia tabaci, transmitted the viruses of this study equally efficiently. Four tomato cultivars (TLB111, TLB130, TLB133, and TLB182) resistant/ tolerant to South Indian ToLCV were screened against the Bangladesh ToLCVs in 2003-04. Although challenged by diverse viruses and potentially mixed infections, disease incidence remained low (6 to 45%) in the resistant cultivars compared with local cultivars (68 to 100%).  相似文献   

Identification of Apoptotic Bodies in Equine Semen     

AB Caselles  A Miro‐Moran  A Morillo Rodriguez  JM Gallardo Bolaños  C Ortega‐Ferrusola  GM Salido  FJ Peña  JA Tapia  IM Aparicio 《Reproduction in domestic animals》2014,49(2):254-262

Apoptosis in the testis is required to ensure an efficient spermatogenesis. However, sometimes, defective germ cells that are marked for elimination during this process escape elimination in the testes, giving rise to ejaculates with increased percentages of abnormal and apoptotic spermatozoa and a high percentage of apoptotic bodies. Apoptosis markers in the ejaculate have been associated with low fertility, either in animals or humans. Therefore, the goal of this study was to investigate whether fresh equine semen contains apoptotic bodies [initially named Merocyanine 540 (M540) bodies] and to study the relationship between the quantity of these bodies and cell concentration, the volume of ejaculate, viability and motility. Moreover, we also studied whether the presence apoptotic bodies in fresh semen was related to the resistance of the stallion spermatozoa to being incubated at 37°C or being frozen and thawed. Fresh equine semen was stained with fluorescent dyes such as M540 and Annexin‐V. Active Caspase 3 was studied in fresh semen through Western blotting and immunofluorescence with a specific antibody. Sperm kinematics was assessed in fresh, incubated and thawed samples using computer‐assisted semen analysis, and viability was evaluated with the LIVE/DEAD Sperm Viability Kit. Overall, our results demonstrate for the first time the presence of apoptotic bodies in equine semen. The quantity of apoptotic bodies was highly variable among stallions and was positively correlated with Caspase 3 activity in fresh samples and negatively correlated with the viability and motility of stallion spermatozoa after the cryopreservation process.  相似文献   

Systemic Immunosuppression by Methylprednisolone and Pregnancy Rates in Goats Undergoing the Transfer of Cloned Embryos     

C Feltrin  CA Cooper  N Mohamad‐Fauzi  VHV Rodrigues  LH Aguiar  S Gaudencio‐Neto  LT Martins  CEM Calderón  AS Morais  IS Carneiro  TM Almeida  ING Silva  JL Rodrigues  EA Maga  JD Murray  AB Libório  LR Bertolini  M Bertolini 《Reproduction in domestic animals》2014,49(4):648-656

The presence of the zona pellucida has been perceived as a requirement for the oviductal transfer of cloned embryos at early stages of development while protecting the embryo from an immune system response. We hypothesized that steroid hormone therapy could reduce a potential cellular immune response after the transfer of zona‐free cloned embryos into the oviduct of recipient female goats. In Experiment 1, seven does were used to study the systemic immunosuppressant effect of the methylprednisolone administration (for 3 days) on blood cell counts. Whole blood was collected prior to treatment with methyprednisolone and then on Days 1, 2, 3, 4, 7, 14, 21 and 28 after the first dose of methylprednisolone for the analysis of haematological parameters. Methylprednisolone treatment significantly reduced circulating white blood cells and neutrophils in comparison with pre‐treatment levels, demonstrating a systemic immunosuppressant effect. In Experiment 2, a group of 58 does were used as recipient females to study the effect of administration of methylprednisolone for 3 days on the establishment of pregnancies after the transfer of zona‐free cloned embryos into the oviducts. No effects on pregnancy rates on Day 30 were observed regarding the distinct treatment groups (control vs. methylprednisolone), the source of oocytes (in vivo‐ vs in vitro‐matured) or the presence or absence of the zona pellucida in embryos. In summary, methylprednisolone was effective at inducing a systemic immunosuppressed state in goats, but the treatment prior to embryo transfer did not affect pregnancy rates. Moreover, pregnancy rates were similar between zona‐free and zona‐intact goat cloned embryos.  相似文献   

Synteny and collinearity in plant genomes   总被引：4，自引：0，他引：4  

Tang H  Bowers JE  Wang X  Ming R  Alam M  Paterson AH 《Science (New York, N.Y.)》2008,320(5875):486-488

Correlated gene arrangements among taxa provide a valuable framework for inference of shared ancestry of genes and for the utilization of findings from model organisms to study less-well-understood systems. In angiosperms, comparisons of gene arrangements are complicated by recurring polyploidy and extensive genome rearrangement. New genome sequences and improved analytical approaches are clarifying angiosperm evolution and revealing patterns of differential gene loss after genome duplication and differential gene retention associated with evolution of some morphological complexity. Because of variability in DNA substitution rates among taxa and genes, deviation from collinearity might be a more reliable phylogenetic character.  相似文献   

Arsenic chemistry in a groundwater aquifer from the Eastern Province of Saudi Arabia     

M. Sadiq  I. Alam 《Water, air, and soil pollution》1996,89(1-2):67-76

Groundwater samples were collected from shallow aquifers underneath an industrial complex in the Eastern Province of Saudi Arabia. Arsenic (As) concentrations in the groundwater samples varied between 10^?8.6 and 10^?6.8 M (0.18 and 11.14 µg L^?1), with an average of 10^?7.5 M (2.19 μ L^?1). The analysis of variance for the analytical data showed that sampling locations had significantly affected As concentrations in the groundwater samples. Analytical and thermodynamic calculations showed that H₂ASO₄ ^? was the most predominant As species in acidic groundwater samples, and HAsO₄ ^2? was the most abundant species in alkaline groundwater samples. Concentrations of H₃AsO₄° and AsO₄ ^3? were too low to be important in this study. Reduced As chemical forms were also expected to be very low. All the groundwater samples were undersaturated with respect to the thermodynamic solubility isotherms of Ca₃(AsO₄)₂(c), Fe₃(AsO₄)₂(c), and Mn₃(AsO₄)₂(c) minerals. Lack of reliable thermodynamic data for these arsenates could be responsible for differences between the theoretical and measured concentrations of As in the shallow groundwater samples. The general trend in the distribution of HAsO₄ ^2? activities in the groundwater samples was parallel to that of the Ca₃(AsO₄)₂ solubility isotherm but different from those of Fe₃(AsO₄)₂(c), and Mn₃(AsO₄)₂(c). These data suggest that As concentrations in the groundwater samples were probably controlled by the precipitation and dissolution of Ca₃(AsO₄)₂ type mineral. A three step hypothesis for As interactions in groundwater/soil system is proposed that combines both solid phase formation and adsorption of As onto the solid colloidal surfaces. This hypothesis is expected to better represent As behavior in groundwater/soil environment.  相似文献