Deforestation and Cultivation with Maize (Zea mays L.) has a Profound Effect on the Bacterial Community Structure in Soil     

Elizabeth Selene Gmez‐Acata  Isaias Valencia‐Becerril  Cesar Valenzuela‐Encinas  Alma Socorro Velsquez‐Rodríguez  Yendi Ebenezer Navarro‐Noya  Nina Montoya‐Ciriaco  Mayra Cecilia Surez‐Arriaga  Aketsally Rojas‐Valdez  Basilio Gabriel Reyes‐Reyes  Marco Luna‐Guido  Luc Dendooven 《Land Degradation \u0026amp; Development》2016,27(4):1122-1130

In this study, the effect of deforestation and cultivation of maize (Zea mays L.) on the physicochemical characteristics and the bacterial community structure in soil were studied at the national park Área de Protección de Flora y Fauna Nevado de Toluca in Mexico. Soil was sampled from three forested areas in the national park, from three deforested areas grazed by animals and from three areas cultivated with maize. The soil was characterized chemically and biologically, whilst the bacterial community structure was investigated through 454 pyrosequencing of the 16S rRNA gene. The pH in the forest soil decreased from 6·1 to 5·3 in the maize‐cultivated soil, whilst the soil organic C content decreased 1·4 times in the arable soil compared with the forest soil. The microbial biomass C decreased 2·9 times in the arable soil compared with the forest soil, but the metabolic quotient qCO₂ (ratio basal respiration to microbial biomass C) nearly doubled. Deforestation and maize cultivation reduced the abundance of Proteobacteria, Actinobacteria and Bacteroidetes, whereas Acidobacteria, Chloroflexi, Gemmatimonadetes and Firmicutes were resistant to these changes. It was found that soil characteristics were affected negatively by deforestation and nearly half of the organic matter was lost, and on these sloped fields, erosion will be high, further decreasing soil fertility. Although the relative abundance of a number of bacterial groups was reduced by deforestation, others were not affected by land‐use change. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Exogenous expression of rat aquaporin-3 enhances permeability to water and cryoprotectants of immature oocytes in the zebrafish (Danio rerio)     

Seki S  Kouya T  Hara T  Valdez DM  Jin B  Kasai M  Edashige K 《The Journal of reproduction and development》2007,53(3):597-604

Movement of water and cryoprotectants through the plasma membrane needs to be accelerated for successful cryopreservation of zebrafish oocytes/embryos, which are much larger than their mammalian counterparts. Aquaporin-3 is a water/solute channel that can transport not only water but also various cryoprotectants. In this study, we attempted to increase the permeability of immature zebrafish oocytes at stage III to water and cryoprotectants by exogenous expression of rat aquaporin-3. Immature zebrafish oocytes were injected with rat aquaporin-3 cRNA and cultured for 5-12 h. Permeability to water and cryoprotectants was then determined based on changes in the volumes of the oocytes in a hypertonic sucrose solution and various cryoprotectant solutions at 25 C. The permeability to water of the aquaporin-3 cRNA-injected oocytes was three times higher than that of intact and water-injected oocytes. The permeability of the aquaporin-3 cRNA-injected oocytes to ethylene glycol, glycerol, propylene glycol, and DMSO was also 2-4 times higher than that of intact oocytes. Thus, the permeability of immature zebrafish oocytes to water and cryoprotectants was enhanced by exogenous expression of aquaporin-3. Cryopreservation of teleost oocytes may be realized through a further increase in permeability.  相似文献   

Experimental test of oyster restoration within eelgrass          下载免费PDF全文

Stephanie R. Valdez  Betsy Peabody  Brian Allen  Brady Blake  Jennifer L. Ruesink 《水产资源保护:海洋与淡水生态系统》2017,27(3):578-587

Biofilm consumption shapes the intestinal microbiota of shrimp (Penaeus vannamei)     

Estefanía Garibay‐Valdez  Luis R. Martínez‐Crdova  Francisco Vargas‐Albores  Teresa Gollas‐Galvn  Asuncin Lago‐Leston  Kadiya Caldern  Marcel Martínez‐Porchas 《Aquaculture Nutrition》2019,25(2):427-435

The effect using biofilm as complementary feed for shrimp (Penaeus vannamei) on the taxonomic and functional profile of its intestinal microbiota was evaluated. Shrimp were cultured for 30 days in two similar low‐water exchange systems, one using commercial feed and the other a combination of commercial feed with biofilm as complementary feed source. Six bacteria phyla were detected in the intestine of shrimp from both treatments (Actinobacteria, Bacteroidetes, Cyanobacteria, Firmicutes, Fusobacteria and Proteobacteria), being Proteobacteria the most abundant (81%–92%). However, this later phylum was significantly less dominant in shrimp fed with biofilm; this drop was associated with a decrease in Vibrio abundance. Differences in the taxonomic profile of bacteria between treatments were also observed through principal component analysis where the diet was the main influencing factor (PC1 72.4%). Regarding functional inference, similarities were detected between treatments. Carbohydrate and energy metabolism were the most abundant functions regardless of time or diet, followed by metabolism of cofactors and vitamins, translation processes, nucleotide metabolism and others. Results suggest that biofilm consumption influenced the taxonomic profile bacteria colonizing the shrimp intestine; however, a functional redundancy was observed despite the use of biofilm as complementary feed. Finally, shrimp fed with biofilm showed a better productive response.  相似文献   

Management of gastrointestinal nematode parasites on sheep farms in New Zealand     

KE Lawrence  DM Leathwick  AP Rhodes  R Jackson  C Heuer  WE Pomroy 《New Zealand veterinary journal》2013,61(5):228-234

AIM: To report current farmer opinions and farming practices relating to control of gastrointestinal nematodes and anthelmintic resistance on sheep farms in New Zealand.

METHODS: An interview-based cross-sectional study of grazing management and anthelmintic useage was conducted by veterinarians on 80 randomly selected sheep farms in New Zealand.

RESULTS: Useable data were returned by 74/80 (92%) farmers who participated in the study. However, despite contacting 400 farmers the target sample size of 100 farms was not reached. The results indicated that only 31% of farms had previously tested for drench resistance, that effective quarantine-drenching of imported stock was not always carried out, and that farmers were more likely to integrate cattle than ewes into their grazing management of lambs. Furthermore, the number of drenches given to lambs had changed little in 25 years. The use of faecal egg counting by farmers has increased.

CONCLUSIONS: Dependence on anthelmintics continues to be high on sheep farms in New Zealand. Whilst the number of drench treatments has changed little, there is more widespread use of persistent or long-acting treatments. Farmers need to be encouraged to monitor the resistance status of nematode populations on their farms and use this information to develop strategies aimed at maintaining susceptible alleles within the parasite populations and conserving the efficacy of existing drug families.  相似文献   

Control of facial muscle development by MyoR and capsulin   总被引：1，自引：0，他引：1  

Lu JR  Bassel-Duby R  Hawkins A  Chang P  Valdez R  Wu H  Gan L  Shelton JM  Richardson JA  Olson EN 《Science (New York, N.Y.)》2002,298(5602):2378-2381

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A comment on the influence of dingoes on the Australian sheep flock     

DM Forsyth  AP Woolnough  DG Nimmo  EG Ritchie  M Kennedy  A Pople  I Watson 《Australian veterinary journal》2014,92(12):461-462

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Simondsia paradoxa: newly recorded nematode parasite from feral pigs in Australia     

DM SPRATT  PM PAVLOV 《Australian veterinary journal》1996,74(5):394-395

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Unusual ovarian activity in a mare preceding the development of an ovarian granulosa cell tumour   总被引：1，自引：0，他引：1  

CHOPIN JB  CHOPIN LK  KNOTT LM  DE KRETSER DM  DOWSETT KF 《Australian veterinary journal》2002,80(1):32-36

An 8-year-old mare, with a foal at foot, was inseminated on foal heat with frozen semen, with the resultant pregnancy lost between days 34 and 41. The right ovary developed a large anovulatory follicle that was non-responsive to multiple doses of ovulating agents. The follicle eventually appeared to luteinise, although plasma progesterone concentrations did not reflect this. Another follicle developed, responded to GnRH and resulted in a pregnancy from frozen semen that went to term with a healthy foal. When the mare was examined after foaling, the structure on the right ovary appeared to be a granulosa cell tumour; the left ovary was smaller than normal and non-functional. Surgical removal of the right ovary before increasing photoperiod resulted in a return to function of the left ovary and a pregnancy to frozen semen on the second cycle following removal. Figures showing concentrations of inhibin, progesterone, androstenedione, oestradiol and testosterone are presented for this entire period. Unusual ovarian activity in the mare might be a prelude to the development of a granulosa cell tumour.  相似文献   

Superovulation response of upgraded indigenous Philippine goat (Capra hircus)     

M B Ocampo  R S Uenishi  C A Valdez  Z Muralla  M Hishinuma  H Kanagawa 《The Japanese journal of veterinary research》1988,36(3-4):249-255

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