Polymorphic microsatellite primers developed from DNA of the endangered Mekong giant catfish,Pangasianodon gigas (Chevey) and cross‐species amplification in three species of Pangasius

The critically endangered Pangasianodon gigas is endemic to the Mekong River. Despite its importance, little is known about its genetic diversity and conservation efforts are hampered. Ten polymorphic dinucleotide microsatellite primer pairs were developed from DNA of P. gigas. The analysis of 20 individuals from hatchery stocks using these primers resulted in two to six alleles/locus; H_O = 0.05–0.95; H_E = 0.05–0.81. All but one locus (Pg‐3) conformed to Hardy–Weinberg expectation. Eight, six and seven primer pairs were amplified with the DNA from Pangasianodon hypophthalmus, Pangasius larnaudii and Pangasius sanitwongsei, respectively. These markers will be useful for genetic monitoring of wild and hatchery stocks of these pangasiids.     

Adenosine as a sleep factor

What puts us to sleep? This question has bothered the mankind for thousands of years, but we still have no definite answer. After abandoning philosophical and religious explanations, science has adopted this question and started to examine it with experimental methods. Two early pioneers in this field, Dr. Ishimori from Japan and Drs. Pieron and Legendre from France developed the concept of hypnotoxin — a factor that accumulates during waking and puts animals and humans to sleep. They were able to show that, indeed, during deprivation of sleep, something accumulates in body — something that can be removed and will induce sleep in another individual. Later research has identified many substances that affect sleep. One of them is adenosine, which fulfils the criteria of a physiologic sleep factor.

     

The peroxisome proliferator activated receptor δ is required for the differentiation of THP-1 monocytic cells by phorbol ester

BACKGROUND: PPARdelta (NR1C2) promotes lipid accumulation in human macrophages in vitro and has been implicated in the response of macrophages to vLDL. We have investigated the role of PPARdelta in PMA-stimulated macrophage differentiation.The THP-1 monocytic cell line which displays macrophage like differentiation in response to phorbol esters was used as a model system. We manipulated the response to PMA using a potent synthetic agonist of PPARdelta, compound F. THP-1 sub-lines that either over-expressed PPARdelta protein, or expressed PPARdelta anti-sense RNA were generated. We then explored the effects of these genetic modulations on the differentiation process. RESULTS: The PPARdelta agonist, compound F, stimulated differentiation in the presence of sub-nanomolar concentrations of phorbol ester. Several markers of differentiation were induced by compound F in a synergistic fashion with phorbol ester, including CD68 and IL8. Over-expression of PPARdelta also sensitised THP-1 cells to phorbol ester and correspondingly, inhibition of PPARdelta by anti-sense RNA completely abolished this response. CONCLUSIONS: These data collectively demonstrate that PPARdelta plays a fundamental role in mediating a subset of cellular effects of phorbol ester and supports observations from mouse knockout models that PPARdelta is involved in macrophage-mediated inflammatory responses.     

1H-NMR spin-spin relaxation time assessment of the reflection coefficient of the Triticale seed cell wall–plasmalemma barrier to mannitol

The ¹H-NMR spin-spin relaxation time (T₂) in Triticale seeds swelling in external osmotica, polyethylene glycol 8000 or mannitol can identify both bound and free water. At the same water content, the free water spin-spin relaxation time increases for seeds imbibed with the mannitol solution, demonstrating inadequate water potential adjustment. The exchange rate of free/bound water molecules is apparently influenced by the driving force for water flow. The reciprocal lifetime of free water molecules, as a measure of water flow through the main cell barrier, was obtained. From a model of the seed as a resistance–capacitor network for water flow, a method was derived for calculating the reflection coefficient σ as a lifetime ratio of the free water molecules in seeds imbibed with two different osmotica (one penetrating across the main cell barrier and one not penetrating) at the same water potential. The ¹H-NMR method and the classical method based on volume rate changes yielded reflection coefficients for mannitol for the cell wall–plasmalemma barrier of 0.78 ± 0.08 and 0.68 ± 0.06, respectively.     

猪蛔虫生长发育与繁殖力的研究

经对猪蛔虫雌虫体长,体重,子宫瞬间怀卵总量,相对毓力测定,发现怀卵总量与体长,体重有密切关系,呈正相关,还发现相对繁殖力,以体重１．０１－３．００ｇ,范围最佳,繁殖能力最强。     

The pssA gene encodes UDP-glucose: polyprenyl phosphate-glucosyl phosphotransferase initiating biosynthesis of Rhizobium leguminosarum exopolysaccharide

Symbiotic nitrogen-fixing bacteria Rhizobium leguminosarum by. viciae VF39 secrete an acidic heteropolysaccharide, the biosynthesis of which involves the stage of polyprenyl diphosphate octasaccharide formation, with its carbohydrate fragment corresponding to the repeating polymer unit. The amino acid analysis of the product of the pssA gene, we have earlier identified, showed its homology to bacterial polyisoprenyl phosphate hexose 1-phosphate transferases catalyzing the formation of phosphodiester bonds between polyprenyl phosphates and hexose 1-phosphates, whose donors are nucleotide sugars. The immunoblotting demonstrated that Rhizobium cells synthesize a protein with a molecular mass of 25 kDa, which implies the translation of the open reading frame occurring from the second initiating codon followed by the protein processing. It was shown that PssA is an integral membrane-bound protein involved in glucose 1-phosphate transfer from UDP-glucose to polyprenyl phosphate to form polyprenyl diphosphate glucose. These results suggest that the pssA gene encodes UDP-glucose:polyprenyl phosphate-glucosyl phosphotransferase.     

小叶臭黄皮叶挥发油化学成分的研究

采用水蒸气蒸馏法提取小叶臭黄皮叶挥发油,运用毛细管气相色谱-质谱联用法对挥发油成分进行了分析,共分离出84个峰,鉴定了其中的66种成分,所鉴定成分占挥发油总量的94.52%.其主要化学成分为α-芹子烯(15.76%)、石竹烯(15.05%)、β-芹子烯(9.54%)、α-蒎烯(6.43%)和α-石竹烯(5.39%)等.     

珍稀濒危植物蒙古扁桃花生物学特性

蒙古扁桃的植株可分为长花丝植株、短花丝植株和中花丝植株。群落花期约50d,单花花期约8d,分为露粉、微开、盛开、凋谢4个时期。过氧化物法测定4个时期花粉均具活力,可保持30d左右,联苯胺-过氧化氢测定柱头可授性,花粉活力与柱头可授性重叠,长花丝植株为8d左右,而中花丝约为5d。蒙古扁桃花一般在9:00开始泌蜜,11:00分泌量达到高峰,之后产蜜量减少直至停止,日泌蜜和散粉集中在10:00～14:00。蒙古扁桃开花受环境的影响。