High yield and high quality DNA from vegetative and sexual tissues of Mexican white pine (Pinus ayacahuite)

Pines are considered to be difficult for DNA extraction. However, from one species to the other there is variation in phenolic profiles and seed size that might affect final DNA yields and quality. Two DNA extraction protocols (CTAB and SDS based) were compared for their ability to produce DNA on leaves, gametophyte and embryo from Pinus ayacahuite, a pine species with a large seed (8 - 18 mm). The DNA obtained from both procedures was quantified and tested by PCR. The CTAB protocol provided higher DNA yields from vegetative tissue and embryo than the SDS method. Embryos (2n) and gametophytes (n) proved to be very good sources of DNA and the DNA isolated was suitable for PCR-RAPD and SSRmarkers. This paper reports the results and describes the modified CTAB protocol

Number of deaths in the first and last weeks of the month, in the municipality of Acatic, Jalisco, México in the twentieth century

We studied the corn stunt spiroplasma (CSS), Spiroplasma kunkelii (Mycoplasmatales: Spiroplasmataceae) and its vector the corn leafhopper Dalbulus maidis (Hemiptera: Cicadellidae) under field conditions in Mexico. We surveyed for the presence of CSS in D. maidis by using PCR on samples of adults collected during the 2000-01 and 2003-04 winter (dry) seasons from irrigated low-elevation sites and un-irrigated high-elevation sites. Also, we determined the body size and number of mature eggs of D. maidis females collected during the dry season in 2004 and in females collected on maize seedlings in the first months (June and July) of the wet (summer) season in 2005. Our PCR results showed that CSS was present in leafhopper adults collected during the 2000-01 and 2003-04 dry seasons in irrigated low-elevation sites. However, in un-irrigated high-elevation sites, CSS was present in corn leafhopper adults caught before, but not during, the dry seasons. In these un-irrigated high-elevation sites, adult leafhoppers without CSS were recovered during the first 2 months (November and December) of the dry season from the foliage of wild perennial grasses. Females collected on wild perennial grasses in December 2004 showed similar head width and wing length to females caught on maize seedlings in June 2005. However, females collected on maize seedlings in July 2005 had the widest heads, longest wings and highest number of mature eggs. The largest body size of these females that arrived in July 2005 indicates that they are immigrants and support the Roff's hypothesis that insect migrants should be larger than nonmigrants. " 2007 Association of Applied Biologists.",,,,,,"10.1111/j.1744-7348.2007.00185.x",,,"http://hdl.handle.net/20.500.12104/41500","http://www.scopus.com/inward/record.url?eid=2-s2.0-36549042573&partnerID=40&md5=2540707205ba1d6a2226c84c8e2bef31",,,,,,"3",,"Annals of Applied Biology",,"37

High yield and high quality DNA from vegetative and sexual tissues of Mexican white pine (Pinus ayacahuite)

Pines are considered to be difficult for DNA extraction. However, from one species to the other there is variation in phenolic profiles and seed size that might affect final DNA yields and quality. Two DNA extraction protocols (CTAB and SDS based) were compared for their ability to produce DNA on leaves, gametophyte and embryo from Pinus ayacahuite, a pine species with a large seed (8 - 18 mm). The DNA obtained from both procedures was quantified and tested by PCR. The CTAB protocol provided higher DNA yields from vegetative tissue and embryo than the SDS method. Embryos (2n) and gametophytes (n) proved to be very good sources of DNA and the DNA isolated was suitable for PCR-RAPD and SSR markers. This paper reports the results and describes the modified CTAB protocol. © 2008 Academic Journals

High yield and high quality DNA from vegetative and sexual tissues of Mexican white pine (Pinus ayacahuite)

Pines are considered to be difficult for DNA extraction. However, from one species to the other there is variation in phenolic profiles and seed size that might affect final DNA yields and quality. Two DNA extraction protocols (CTAB and SDS based) were compared for their ability to produce DNA on leaves, gametophyte and embryo from Pinus ayacahuite, a pine species with a large seed (8 - 18 mm). The DNA obtained from both procedures was quantified and tested by PCR. The CTAB protocol provided higher DNA yields from vegetative tissue and embryo than the SDS method. Embryos (2n) and gametophytes (n) proved to be very good sources of DNA and the DNA isolated was suitable for PCR-RAPD and SSR markers. This paper reports the results and describes the modified CTAB protocol. � 2008 Academic Journals

Modelling of optical absorption of silver NP's produced by UV radiation embedded in mesostructured silica films

A detailed protocol is described to induce chronic stress in BALB/c mice, which affects the hypothalamic-pituitary-adrenal (HPA) axis. The protocol is based on a combination of two mild physical stressors: restraint stress and forced swimming. Physical stressors were applied on an alternative schedule: one day restraint, next day swimming, during a 28-day period. Mice were sacrificed at days 7, 14, 21 and 28 and plasma was obtained. Optimized chromatographic system with electrochemical detection and a commercially available enzyme immunoassay kit were used to measure catecholamines [representative of the activation of the autonomic nervous system (ANS)] and corticosterone (representative of the activation of the HPA axis). Corticosterone levels increased in mice under stress and remained significantly higher in stressed mice compared to control animals throughout the experimental procedure, indicating that mice did not show habituation to the combined stress. In our experimental conditions, catecholamine levels were not useful as an index of stress. The stress model applied here provoked a steady activation of the HPA axis resulting in the constant secretion of corticosterone from the adrenal gland, which may prevent the activation of the ANS axis. The simple and economic stress model presented here affected the HPA axis but not the ANS of BALB/c mice and is useful for the study of metabolic stress-related gastric pathology and stress hormone secretion in mice. " 2012 Elsevier B.V.",,,,,,"10.1016/j.jneumeth.2012.10.015",,,"http://hdl.handle.net/20.500.12104/38931","http://www.scopus.com/inward/record.url?eid=2-s2.0-84871956946&partnerID=40&md5=32c80de8779c420abf941e955b887ae

A chronic combinatory stress model that activates the HPA axis and avoids habituation in BALB/C mice

A detailed protocol is described to induce chronic stress in BALB/c mice, which affects the hypothalamic-pituitary-adrenal (HPA) axis. The protocol is based on a combination of two mild physical stressors: restraint stress and forced swimming. Physical stressors were applied on an alternative schedule: one day restraint, next day swimming, during a 28-day period. Mice were sacrificed at days 7, 14, 21 and 28 and plasma was obtained. Optimized chromatographic system with electrochemical detection and a commercially available enzyme immunoassay kit were used to measure catecholamines [representative of the activation of the autonomic nervous system (ANS)] and corticosterone (representative of the activation of the HPA axis). Corticosterone levels increased in mice under stress and remained significantly higher in stressed mice compared to control animals throughout the experimental procedure, indicating that mice did not show habituation to the combined stress. In our experimental conditions, catecholamine levels were not useful as an index of stress. The stress model applied here provoked a steady activation of the HPA axis resulting in the constant secretion of corticosterone from the adrenal gland, which may prevent the activation of the ANS axis. The simple and economic stress model presented here affected the HPA axis but not the ANS of BALB/c mice and is useful for the study of metabolic stress-related gastric pathology and stress hormone secretion in mice. © 2012 Elsevier B.V

The inner galactic structure traced by molecular clouds associated with ultra-compact hii regions

Homopteran vectors (e.g., leafhoppers) of plant pathogens are vessels for reproduction of cell wall-free bacteria. These vectors also serve as hosts for larval parasitoid dipterans, hymenopterans, and strepsipterans. However, no study has explored the relationship among these wall-free bacteria and parasitoid larvae within the insect host. We studied the corn stunt spiroplasma (CSS), Spiroplasma kunkelii Whitcomb (Mycoplasmatales: Spiroplasmataceae), a bacterium that originated from secondary symbionts that cause corn stunt disease in maize, Zea mays L., and its reproduction in the haemolymph of the corn leafhopper, Dalbulus maidis (Delong and Wolcott) (Homoptera: Cicadellidae). We also studied the dryinid parasitoid Gonatopus bartletti Olmi (Hymenoptera: Dryinidae), the larva of which feeds in the corn leafhopper haemolymph. Our results showed that when CSS and the wasp coexisted in D. maidis, the development of the parasitoid was not affected by S. kunkelii. Parasitoid development was successfully completed when leafhoppers acquired S. kunkelii before or after parasitism and when CSS had median (10 days) and long (20 days) incubation periods in the leafhopper before parasitization. The presence of S. kunkelii did not affect parasitoid development to the adult stage. However, polymerase chain reaction showed that the presence (survival) of S. kunkelii in the leafhopper was negatively affected by the parasitoid larva. Fewer leafhoppers had CSS before and after parasitization compared with leafhoppers that only acquired the CSS. This negative effect helps to explain the high parasitism rate by G. bartletti in D. maidis and the low presence of S. kunkelii in the corn leafhopper when CSS and the wasp parasitoid overlap throughout their geographic distribution. The parasitoid larva may negatively affect S. kunkelii by (1) producing antibacterial peptides that are toxic to CSS; (2) producing teratocytes that take nutrients from the host for larval development, but these nutrients are required by CSS; (3) affecting, indirectly, CSS through other symbiotic microorganisms; and (4) producing proteins with antibacterial activity that are present in the venom of the wasp parasitoid. " 2006 The Netherlands Entomological Society.",,,,,,"10.1111/j.1570-7458.2006.00409.x",,,"http://hdl.handle.net/20.500.12104/45232","http://www.scopus.com/inward/record.url?eid=2-s2.0-33646698846&partnerID=40&md5=8e64e1a1ce3836fa5763a2b432801548",,,,,,"3",,"Entomologia Experimentalis et Applicata",,"18