Novel combination of a biosurfactant with entomopathogenic fungi enhances efficacy against Bemisia whitefly     

Jaqueline do Nascimento Silva  Gabriel M Mascarin  Rui de Paula Vieira de Castro  Leda R Castilho  Denise MG Freire 《Pest management science》2019,75(11):2882-2891

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Influence of the Freezing Technique (Nitrogen Liquid vs Ultrafreezer of −152°C) and Male-to-Male Variation Over the Semen Quality in Canarian Mastiff Breed Dogs     

M Batista  D Alamo  F González  MG Cruz  A Gracia 《Reproduction in domestic animals》2006,41(5):423-428

This study was carried out to assess the in vitro quality of canine semen frozen in an ultrafreezer at -152 degrees C and to evaluate the male-to-male variation of frozen semen in five male dogs of the Canarian Mastiff breed. Four ejaculates of each dog were processed individually (5% glycerol and 0.5% Equex) to reach a final concentration of 100 x 10(6) spermatozoa/ml. Then, two freezing techniques were tested to assess the seminal quality (sperm motility, live spermatozoa and abnormal sperm cell percentages) at 1, 30, 60, 120 and 360 days after freezing: (i) semen was frozen and stored in liquid nitrogen; (ii) semen was frozen and stored in the ultrafreezer at -152 degrees C. After freezing-thawing, both freezing protocols showed no significant differences in sperm motility and the percentages of live and abnormal spermatozoa. On the other hand, the microscopic characteristics of spermatozoa in fresh semen were practically similar among males; however, after the semen processing and freezing, significant differences were observed (p < 0.05) among males, especially as regards sperm motility. This inter-individual variability was detected in both freezing protocols, showing that the male-to-male variation in the seminal quality post-freezing was independent of the freezing technique used. The in vitro results obtained in the Canarian Mastiff breed confirmed that the use of ultra-freezers at -152 degrees C is a potential alternative to liquid nitrogen for storing canine semen for long periods of time.  相似文献   

Luteal Characteristics and Progesterone Production on Day 5 of the Bovine Oestrous Cycle     

MP Green  GE Mann  MG Hunter 《Reproduction in domestic animals》2007,42(6):643-647

In this study we have examined luteal function in non-lactating and late lactation dairy cows on day 5 of the cycle, during the period of the post-ovulatory progesterone rise. Comparison of luteal progesterone content and in vitro synthetic capacity with circulating plasma progesterone demonstrated that circulating progesterone concentration is a function of total luteal activity rather than the activity of individual units of tissue. Incubation of luteal tissue in vitro demonstrated stimulatory activity of LH and IGF-I, and to a greater degree IGF-II, on luteal progesterone synthesis. Finally the study showed no effect of double ovulation on luteal function. Occurrence of double ovulation in 35% of animals was not associated with any difference in luteal function or plasma progesterone concentrations.  相似文献   

Insect midgut structures and molecules as targets of plant‐derived protease inhibitors and lectins     

Thiago H Napoleo  Lidiane P Albuquerque  Nataly DL Santos  Isabella CV Nova  Thmarah A Lima  Patrícia MG Paiva  Emmanuel V Pontual 《Pest management science》2019,75(5):1212-1222

The midgut of insects is involved in digestion, osmoregulation and immunity. Although several defensive strategies are present in this organ, its organization and function may be disturbed by some insecticidal agents, including bioactive proteins like lectins and protease inhibitors (PIs) from plants. PIs interfere with digestion, leading to poor nutrient absorption and decreasing amino acid bioavailability. Intake of PIs can delay development, cause deformities and reduce fertility. Ingestion of PIs may lead to changes in the set of proteases secreted in the insect gut, but this response is often insufficient and results in aggravation of the malnutrition status. Lectins are proteins that are able to interact with glycoconjugates, including those linked to cell surfaces. Their effects on the midgut include disruption of the peritrophic matrix, brush border and secretory cell layer; induction of apoptosis and oxidative stress; interference with nutrient absorption and transport proteins; and damaging effects on symbionts. In addition, lectins can cross the intestinal barrier and reach the hemolymph. The establishment of resistant insect populations due to selective pressure resulting from massive use of a bioactive protein is an actual possibility, but this can be minimized by the multiple mode‐of‐action of these proteins, mainly the lectins. © 2018 Society of Chemical Industry  相似文献   

Structure,dynamics and movement patterns of the Australian pig industry     

IJ East  J Davis  ESG Sergeant  MG Garner 《Australian veterinary journal》2014,92(3):52-57

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Husbandry Factors and the Resumption of Luteal Activity in Open and Zero‐Grazed Dairy Cows in Urban and Peri‐Urban Kampala,Uganda     

BM Kanyima  R Båge  DO Owiny  T Ntallaris  J Lindahl  U Magnusson  MG Nassuna‐Musoke 《Reproduction in domestic animals》2014,49(4):673-678

The study investigated the influence of selected husbandry factors on interval to resumption of post‐partum cyclicity among dairy cows in urban and peri‐urban Kampala. A prospective study of 85 day post‐partum period of 59 dairy cows in open (n = 38) and zero grazing (n = 21) systems was conducted on 24 farms. Cows of parity 1–6 were recruited starting 15–30 days post‐partum. Progesterone (P4) content in milk taken at 10–12 day intervals was analysed using ELISA. The cow P4 profiles were classified into ‘normal’ (< 56 days), ‘delayed’ (> 56 days), ‘ceased’ or ‘prolonged’ (if started < 56 days but with abnormal P4 displays) resumption of luteal activity and tested for association with husbandry and cow factors. Of the 59 cows, luteal activity in 81.4% resumed normally and in 18.6%, delayed. Only 23.7% maintained regular luteal activity, while the others had ceased (10.2%), prolonged (37.3%) or unclear luteal activity (20.3%). There were no differences between open and zero‐grazed cows. Milk production was higher (p < 0.05) in zero than open grazing, in urban than peri‐urban and in cows fed on brew waste (p < 0.001) compared with mill products and banana peels. Results suggest that luteal activity resumes normally in a majority of cows, although only a minority experienced continued normal cyclicity once ovulation had occurred, in the two farming systems irrespective of feed supplements or water, and that supplementing with brew waste is beneficial for milk production.  相似文献   

Potential Cuban agricultural export profile under open trade between the U. S. and Cuba     

Jose Alvarez  William A. Messina Jr. 《Agriculture and Human Values》1993,10(3):61-74

The sweeping changes that have taken place in the Eastern European countries and the former Soviet Union have detrimentally impacted an already weak Cuban economy. The establishment of the Special Period (1990-) embodies increasing austerity, especially in the inputs market. Recent economic liberalization policies in Cuba may lead to a more market-oriented economy, the lifting of the U. S. embargo, and commercial relations between the two countries. There is concern on the potential impact that resumption of trade may have on the U. S. and Florida's agricultural economy. This study implies potential costs for the citrus, sugar, horticultural, and seafood industries in Florida, while potential Florida exports unveil trade opportunities of a large magnitude. Further research is needed to quantify potential benefits and costs. Of special importance is the fate of Cuba's recent program on low-input sustainable agriculture once large amounts of inputs become available.  相似文献   

Adatom pairing structures for Ge on si(100): the initial stage of island formation     

XR Qin  MG Lagally 《Science (New York, N.Y.)》1997,278(5342):1444-1447

With the use of scanning tunneling microscopy, it is shown that germanium atoms adsorbed on the (100) surface of silicon near room temperature form chainlike structures that are tilted from the substrate dimer bond direction and that consist of two-atom units arranged in adjoining substrate troughs. These units are distinctly different from surface dimers. They may provide the link missing in our understanding of the elementary processes in epitaxial film growth: the step between monomer adsorption and the initial formation of two-dimensional growth islands.  相似文献   

Atomistic Processes in the Early Stages of Thin-Film Growth     

Z Zhang  MG Lagally 《Science (New York, N.Y.)》1997,276(5311):377-383

Growth of thin films from atoms deposited from the gas phase is intrinsically a nonequilibrium phenomenon governed by a competition between kinetics and thermodynamics. Precise control of the growth and thus of the properties of deposited films becomes possible only after an understanding of this competition is achieved. Here, the atomic nature of the most important kinetic mechanisms of film growth is explored. These mechanisms include adatom diffusion on terraces, along steps, and around island corners; nucleation and dynamics of the stable nucleus; atom attachment to and detachment from terraces and islands; and interlayer mass transport. Ways to manipulate the growth kinetics in order to select a desired growth mode are briefly addressed.  相似文献   

Inhibition of polyphenol oxidases activity by various dipeptides   总被引：1，自引：0，他引：1  

Girelli AM  Mattei E  Messina A  Tarola AM 《Journal of agricultural and food chemistry》2004,52(10):2741-2745

In an effort to develop natural and nontoxic inhibitors on the activity of mushroom polyphenol oxidase (PPO) the effect of various glycyl-dipeptides (GlyAsp, GlyGly, GlyHis, GlyLeu, GlyLys, GlyPhe, GlyPro, GlyTyr) was investigated. The inhibition study with dihydroxyphenylalanine (DOPA) as substrate is based on separation of the enzymatic reaction components by reversed phase HPLC and the UV detection of the dopachrome formed. The results have evidenced that several of tested dipeptides inhibited PPO activity in the range of 20-40% while GlyPro and GlyLeu had no effect. The study has also permitted the characterization of the following kinetic pattern: a linear-mixed-type mechanism for GlyAsp, GlyGly, GlyLys, and GlyPhe and a hyperbolic-mixed-type for GlyTyr. It was not possible to identify the inhibition mechanism for GlyHis, although it affects PPO activity. In addition the effects of GlyAsp, GlyLys and GlyHis were evaluated for lessening the browning of fresh Golden Delicious apple and Irish White Skinned potato. The effectiveness of such inhibitors was determined by the difference between the colors observed in the dipeptide-treated sample and the controls using the color space CIE-Lab system. The % browning inhibition on potato (20-50%) was greater than of apple (20-30%) by the all tested dipeptides. Only GlyLys presented the significant value of 50%.  相似文献