Chimpanzee fetal G gamma and A gamma globin gene nucleotide sequences provide further evidence of gene conversions in hominine evolution

The fetal globin genes G gamma and A gamma from one chromosome of a chimpanzee (Pan troglodytes) were sequenced and found to be closely similar to the corresponding genes of man and the gorilla. These genes contain identical promoter and termination signals and have exons 1 and 2 separated by the conserved short intron 1 (122 bp) and exons 2 and 3 separated by the more rapidly evolving, larger intron 2 (893 bp and 887 bp in chimpanzee G gamma and A gamma, respectively). Each intron 2 has a stretch of simple sequence DNA (TG)n serving possibly as a "hot spot" for recombination. The two chimpanzee genes encode polypeptide chains that differ only at position 136 (glycine in G gamma and alanine in A gamma) and that are identical to the corresponding human chains, which have aspartic acid at position 73 and lysine at 104 in contrast to glycine and arginine at these respective positions of the gorilla A gamma chain. Phylogenetic analysis by the parsimony method revealed four silent (synonymous) base substitutions in evolutionary descent of the chimpanzee G gamma and A gamma codons and none in the human and gorilla codons. These Homininae (Pan, Homo, Gorilla) coding sequences evolved at one-tenth the average mammalian rate for nonsynonymous and one-fourth that for synonymous substitutions. Three sequence regions that were affected by gene conversions between chimpanzee G gamma and A gamma loci were identified: one extended 3' of the hot spot with G gamma replaced by the A gamma sequence, another extended 5' of the hot spot with A gamma replaced by G gamma, and the third conversion extended from the 5' flanking to the 5' end of intron 2, with G gamma replaced here by the A gamma sequence. A conversion similar to this third one has occurred independently in the descent of the gorilla genes. The four previously identified conversions, labeled C1-C4 (Scott et al. 1984), were substantiated with the addition of the chimpanzee genes to our analysis (C1 being shared by all three hominines and C2, C3, and C4 being found only in humans). Thus, the fetal genes from all three of these hominine species have been active in gene conversions during the descent of each species.      

Comparison of four modeling tools for the prediction of potential distribution for non-indigenous weeds in the United States

This study compares four models for predicting the potential distribution of non-indigenous weed species in the conterminous U.S. The comparison focused on evaluating modeling tools and protocols as currently used for weed risk assessment or for predicting the potential distribution of invasive weeds. We used six weed species (three highly invasive and three less invasive non-indigenous species) that have been established in the U.S. for more than 75 years. The experiment involved providing non-U. S. location data to users familiar with one of the four evaluated techniques, who then developed predictive models that were applied to the United States without knowing the identity of the species or its U.S. distribution. We compared a simple GIS climate matching technique known as Proto3, a simple climate matching tool CLIMEX Match Climates, the correlative model MaxEnt, and a process model known as the Thornley Transport Resistance (TTR) model. Two experienced users ran each modeling tool except TTR, which had one user. Models were trained with global species distribution data excluding any U.S. data, and then were evaluated using the current known U.S. distribution. The influence of weed species identity and modeling tool on prevalence and sensitivity effects was compared using a generalized linear mixed model. Each modeling tool itself had a low statistical significance, while weed species alone accounted for 69.1 and 48.5% of the variance for prevalence and sensitivity, respectively. These results suggest that simple modeling tools might perform as well as complex ones in the case of predicting potential distribution for a weed not yet present in the United States. Considerations of model accuracy should also be balanced with those of reproducibility and ease of use. More important than the choice of modeling tool is the construction of robust protocols and testing both new and experienced users under blind test conditions that approximate operational conditions.     

Transient expression of β-glucuronidase in plastids of various plant cells and tissues delivered by a pneumatic particle gun

Chloroplast expression plasmids pTRBCL-GUS (tobaccorbcL promoter-gusA-tobaccorbcL terminator) and pHHU3004 (spinach ‘x gene’ promoter-gusA-spinachrbcL terminator) and a control nuclear expression plasmid pBI221 (CaMV 35S promoter-gusA-NOS terminator) were introduced separately into cultured cells and tissues of tobacco andArabidopsis thaliana, as well as into cultured cells of the lower land plants liverwort and hornwort by a pneumatic particle gun. The pTRBCL-GUS and pHHU3004 plasmids produced many blue spots in the BY-2 cells and the roots ofArabidopsis thaliana, but not in any of the green cells or tissues. The results suggest that the pTRBCL-GUS and pHHU3004 plasmids are expressed more in proplastids and amyloplasts than in chloroplasts. GUS activities of the BY-2 cells bombarded with pTRBCL-GUS and pHHU3004 were insensitive to α-amanitin treatment (10 and 50 μg/ml), while that of the cells with pBI221 greatly decreased by the same treatment. Hence, it is likely that the pTRBCL-GUS and pHHU3004 plasmids were substantially expressed in the proplastids.     

A simple pressure filtration apparatus for field use

A simple apparatus for pressure-filtering water samples in the field is described. It is used in conjunction with the low pressure outlet of a standard regulator attached to an aqualung. The apparatus is useful in situations where electricity to run electric vacuum pumps is not available and is superior to conventional hand vacuum pumps.     

A molecular view of primate phylogeny and important systematic and evolutionary questions

Phylogenetic analysis of extensive nucleotide sequence data from primate beta-globin gene clusters elucidates the systematics and evolution of the order Primates and reveals that rates of accumulation of mutations vary by as much as a factor of seven among different primate lineages. The picture of primate phylogeny from DNA sequences clarifies many ambiguities of the morphological picture. In the molecular picture, dwarf and brown lemurs group together into superfamily Lemuroidea, Lemuroidea and Lorisoidea into suborder Strepsirhini, and Tarsius and Anthropoidea into suborder Haplorhini. The molecular picture also provides both significant evidence for a human-chimpanzee clade that narrowly excludes gorilla and overwhelming evidence for the gorilla-chimpanzee-human clade within Hominoidea. Rates of DNA sequence evolution appear to have been fastest in the early primates ancestral to Anthropoidea and next fastest on the lorisoid branch. Rates were slowest over the past 25 Myr of hominoid descent, suggesting that mechanisms lowering the mutation rate evolved in correlation with lengthened life spans.     

Evaluation of two methods for quantifying passeriform lice

Two methods commonly used to quantify ectoparasites on live birds are visual examination and dust‐ruffling. Visual examination provides an estimate of ectoparasite abundance based on an observer's timed inspection of various body regions on a bird. Dust‐ruffling involves application of insecticidal powder to feathers that are then ruffled to dislodge ectoparasites onto a collection surface where they can then be counted. Despite the common use of these methods in the field, the proportion of actual ectoparasites they account for has only been tested with Rock Pigeons (Columba livia), a relatively large‐bodied species (238–302 g) with dense plumage. We tested the accuracy of the two methods using European Starlings (Sturnus vulgaris; ～75 g). We first quantified the number of lice (Brueelia nebulosa) on starlings using visual examination, followed immediately by dust‐ruffling. Birds were then euthanized and the proportion of lice accounted for by each method was compared to the total number of lice on each bird as determined with a body‐washing method. Visual examination and dust‐ruffling each accounted for a relatively small proportion of total lice (14% and 16%, respectively), but both were still significant predictors of abundance. The number of lice observed by visual examination accounted for 68% of the variation in total abundance. Similarly, the number of lice recovered by dust‐ruffling accounted for 72% of the variation in total abundance. Our results show that both methods can be used to reliably quantify the abundance of lice on European Starlings and other similar‐sized passerines.     

Thin-alginate-layer technique for protoplast culture of tobacco leaf protoplasts: Shoot formation in less than two weeks

Summary Regeneration of plants from protoplasts is regarded a difficult and lengthy procedure which requires well developed skills on the side of the experimenter. Therefore, where alternative procedures for genetic engineering of plants are available, protoplast-based techniques are frequently avoided. Here, we demonstrate, that by our newly developed thin-alginate-layer technique it is possible to regenerate shoots from leaf protoplasts ofNicotiana tabacum L. at very high efficiency and very rapidly, with the first shoots appearing within less than two weeks. Root formation is induced on a third medium with first roots being found after only 10 more days of culture.     

TCR and CD3 antibody cross-reactivity in 44 species.

The production of monoclonal antibodies is very costly, and antibodies are only available for a limited number of species. Until a more cost effective method of antibody production is found, identification of cross-reactive antibodies is an alternative approach that can provide investigators studying immunity in minor species with valuable antibody reagents. Flow cytometry was used to test 21 monoclonal antibodies (mAb), raised against alphabeta and gammadelta T cell receptors and CD3 from human and five animal species, for cross-reactivity in 44 different species including 16 species of nonhuman primates, marsupials, carnivores, lagomorphs, rodents, ruminants, swine, cetacean, horse, birds, a reptile, and fish. Fifteen of the mAbs cross-reacted with orthologous molecules in one or more species. Two antibodies, anti-human TCR gammadelta (B1.1), and anti-human CD3 (SP34) were found to costain in 13 species of nonhuman primates. This study has identified valuable new reagents for studying T cell populations in different animal species and for the first time characterized antibodies useful for studying gammadelta T cell populations in many species of primates. These antibodies may be used for further immunity research in species with less well-characterized immune systems.     

重组hPRL-1的表达纯化及其理化和酶学性质研究

目的:表达纯化hPRL-1重组蛋白,分析其理化性质及酶学特性。方法:热激法将重组pET15b质粒转化入E.coli BL21中,IPTG诱导表达出His-tagged hPRL-1蛋白。使用Ni-NTA亲和层析法结合Mono Q离子交换层析法纯化。用SDS-PAGE法和Western Blot法进行表达情况的定性定量分析,并使用HPLC法鉴定蛋白纯度,计算出蛋白分子量,圆盘等电聚焦电泳分析重组蛋白等电点。比较分析以pNPP、4-MUP和DiFMUP为底物时的酶促反应动力学。同时以pNPP为底物测定酶的最适pH值;以4-MUP为底物测定酶的最适温度,分析探讨缓冲液离子强度与蛋白酪氨酸酶通用抑制剂钒酸钠对酶活力的影响。结果:以亲和层析和离子交换层析结合,可以纯化得到纯度约为95%的蛋白。测得蛋白分子量为24.54kD,等电点为9.11。以pNPP、4-MUP和DiFMUP为底物时Km分别为3720μmol/L,130μmol/L和50μmol/L。酶的最适pH值为7.6,最适温度为34℃。结论:纯化所得蛋白为目的蛋白hPRL-1;两步纯化相结合可以得到纯度较高的蛋白;三种底物特异性依次为DiFMUP>4-MUP>pNPP。