Diet of the Indochinese silvered langur (Trachypithecus germaini) in Kien Luong Karst area,Kien Giang Province

The Indochinese silvered langur (Trachypithecus germaini) is distributed to the west of Mekong River in Cambodia, Lao PDR, Thailand and Vietnam. During a two‐year study, from May 2014 to May 2016, we collected 320.44 hr of behavior, with 17,040 feeding bouts recorded (142 hr) for T. germaini on Chua Hang Karst Mountain, Kien Luong District, Kien Giang Province, Vietnam. Feeding accounted for 45% of the Indochinese silvered langurs’ activity budget. The plant diet of the Indochinese silvered langurs was principally composed of young leaves (58%), followed by mature leaves (9.5%), fruits (22.7%), flowers (4.7%), buds (3.3%), petioles (1.2%), and other (0.5%). A total of 58 plant species were fed on by the silvered langurs, and leaves of eight species (Phyllathus reticulatus, Ficus rumphii, Ficus tinctoria, Ficus microcarpa, Cayratia trifolia, Streblus ilicifolia, Combretum latifolium, and Streblus asper) were fed on throughout the year. P. reticulatus was most frequently eaten (13.9% feeding time, n = 1,733). Food selection differed significantly between months and seasons. The Indochinese silvered langurs ate 27 plant species in the wet season compared with 23 plant species in the dry season. Leaf chemical composition of two food categories, 16 eaten species (with 10 most frequently consumed species and six least consumed species), and four noneaten species, were analyzed. Feeding samples from eaten species in the Indochinese silvered langurs's diet contained lower amounts of condensed tannin, lignin, protein, ash, and lipids, but a higher amount of total sugar compared with samples from noneaten species. Furthermore, the most frequently consumed species contained lower amounts of lignin compared with the less frequently consumed species. Using a generalized linear model with five variables, including neutral detergent fiber (NDF), total sugar, lignin, lipid, and calcium (Ca) indicated that NDF positively correlated and lignin content negatively correlated with feeding records in the diet of these langur.     

Amino acid sequence of rat mast cell protease I (chymase)

The amino acid sequence has been determined for rat mast cell protease I (RMCP I), a product of peritoneal mast cells. The active enzyme contains 227 residues, including three corresponding to the catalytic triad characteristic of serine protease (His-57, Asp-102, and Ser-195 in chymotrypsin). A computer search for homology indicates 73% and 33% sequence identity of RMCP I with rat mast cell protease II from mucosal mast cells and bovine chymotrypsin A, respectively. When the structure of RMCP I is compared to those of cathepsin G from human neutrophils and two proteases expressed in activated lymphocytes, 48-49% of the sequences are identical in each case. RMCP I has six half-cystine residues at the same positions as in RMCP II, cathepsin G, and the two lymphocyte proteases, suggesting disulfide pairs identical with those reported for RMCP II. A disulfide bond near the active site seryl residue and substrate binding site, present in pancreatic and plasma serine proteases, is not found in RMCP I or in the other cellular proteases. These results indicate that RMCP I and other chymotrypsin-like proteases of granulocyte and lymphocyte origin are more closely related to each other than to the pancreatic or plasma serine proteases.     

Limited chloroplast gene transfer via recombination overcomes plastomegenome incompatibility between Nicotiana tabacum and Solanum tuberosum

Green cybrids with a new nucleus-chloroplast combination cannot be selected after protoplast fusion in the intersubfamilial Nicotiana-Solanum combination. As an approach to overcome the supposed plastomegenome incompatibility, a partial plastome transfer by genetic recombination has been considered. After fusions of protoplasts of a light-sensitive Nicotiana tabacum (tobacco) plastome mutant and lethally irradiated protoplasts of wild-type Solanum tuberosum (potato), a single green colony was recovered among 2.5×10⁴ colonies. The regenerated plants had tobacco-like (although abnormal) morphology, but were normally green, and sensitive to tentoxin, demonstrating chloroplast markers of the potato parent. Restriction enzyme analysis of the chloroplast DNA (cpDNA) revealed recombinant, nonparental patterns. A comparison with physical maps of the parental cpDNA demonstrated the presence of a considerable part of the potato plastome flanked by tobacco-specific regions. This potacco plastome proved to be stable in backcross and backfusion experiments, and normally functional in the presence solely of N. tabacum nucleus.     

Amino acid sequence of a mouse mucosal mast cell protease

The amino acid sequence has been determined of a mouse mucosal mast cell protease isolated from the small intestines of mice infected with Trichinella spiralis. The active protease contains 226 residues. Those corresponding to the catalytic triad of the active site of mammalian serine proteases (His-57, Asp-102, and Ser-195 in chymotrypsin) occur in identical positions. A computer search for homology indicates 74.3% and 74.1% sequence identity of the mouse mast cell protease compared to those of rat mast cell proteases I and II (RMCP I and II), respectively. The six half-cystine residues in the mouse mast cell protease are located in the same positions as in the rat mast cell proteases, cathepsin G, and the lymphocyte proteases, suggesting that they all have identical disulfide bond arrangements. At physiological pH, the mouse and rat mucosal mast cell proteases have net charges of +3 and +4, respectively, as compared to +18 for the protease (RMCP I) from rat connective tissue mast cells. This observation is consistent with the difference in solubility between the mucosal and connective tissue mast cell proteases when the enzymes are extracted from their granules under physiological conditions.     

Medicago truncatula,a model plant for studying the molecular genetics of theRhizobium-legume symbiosis

Medicago truncatula has all the characteristics required for a concerted analysis of nitrogen-fixing symbiosis withRhizobium using the tools of molecular biology, cellular biology and genetics.M. truncatula is a diploid and autogamous plant has a relatively small genome, and preliminary molecular analysis suggests that allelic heterozygosity is minimal compared with the cross-fertilising tetraploid alfalfa (Medicago sativa). TheM. truncatula cultivar Jemalong is nodulated by theRhizobium meliloti strain 2011, which has already served to define many of the bacterial genes involved in symbiosis with alfalfa. A genotype of Jemalong has been identified which can be regenerated after transformation byAgrobacterium, thus allowing the analysis ofin-vitro-modified genes in an homologous transgenic system. Finally, by virtue of the diploid, self-fertilising and genetically homogeneous character ofM. truncatula, it should be relatively straightforward to screen for recessive mutations in symbiotic genes, to carry out genetic analysis, and to construct an RFLP map for this plant.     

Measurements of genetic variability for symbiotic dinitrogen fixation in fieldgrwon fababean (Vicia faba L.) using a low level15N-tracer technique

Before starting a breeding program aimed at improving the nitrogen nutrition ofVicia faba, the authors tried an alternative technique to the acetylene reduction assay, to measure some genetic variability in the plant material. The quantity of dinitrogen fixed by several cultivars ofVicia faba was estimated using a low enrichment¹⁵N tracer method and high precision¹⁵N mass spectrometry. The fababeans were cultivated for two years in two different soils. The percentage of fixed dinitrogen in the seed varied between genotypes from 40 to 83% of the total nitrogen and was positively correlated with the total seed nitrogen (r=0.64 to 0.86). A highly significant positive correlation was also found between the total seed nitrogen and the quantity of fixed dinitrogen in the seed (r=0.95 to 0.99). The technique used to measure dinitrogen fixation proved to be useful and reliable enough to discriminate between various genotypes, grown over a period of two years in two different soils. However, several non-fixing control plants showed significant differences in their¹⁵N enrichment and the problem of choosing a good reference plant was raised and discussed.     

A stochastic model of mutant growth due to mutation in tumors,based on stem cell considerations

A stochastic model of the evolution of mutant subpopulations from stem cells in a human tumor system is derived. From the model, the growth of mutants (both stem cell mutants and overall mutants) due to mutation of tumor stem cells during growth is explored in detail. This allows one to relate the mutant stem cell and overall tumor mutant cell population sizes. The relation of these average sizes is derived for large tumor size and confirms the result of the model due to MacKillop et al. [4], which is based on three tumor cell subpopulations: stem, transitional, and end cells. Furthermore, the results of the stem cell statistics obtained are the same as those obtained from the filtered Poisson process approach [2].     

Effect of human T-cell leukemia virus type I tax protein on activation of the human vimentin gene.

We report that the expression of the vimentin gene, a cytoskeletal growth-regulated gene, is activated in trans by the Tax (p40x) transactivator protein encoded by the human T-cell leukemia virus type I. Expression of the Tax protein activates a number of cellular genes, such as those coding for the alpha chain of the high-affinity interleukin-2 receptor and interleukin-2. These findings indicate that the Tax protein is involved in the unregulated T-cell growth associated with human T-cell leukemia virus type I infection. Higher levels of vimentin mRNA were expressed in two human T-cell leukemia virus type I-transformed T cell lines, C91/PL and C81-66/45, when compared with that in Jurkat T cells. We demonstrate that this activation is conferred by the vimentin upstream flanking sequences. Indeed, enhanced activity was detected when constructs with the vimentin promoter linked to the chloramphenicol acetyltransferase gene were transfected in HeLa cells and in two cell lines of hematopoietic origin (Jurkat T lymphoblastoid cells and U937 promonocytic cells) together with a Tax expression plasmid. By introducing a series of deletions in the vimentin promoter, we further restrict these sequences to 30 base pairs, located between 241 and 210 base pairs upstream of the mRNA cap site. A 40-base-pair oligonucleotide containing this regulatory region proved sufficient to confer Tax inducibility upon a heterologous promoter linked to chloramphenicol acetyltransferase. Importantly, this segment includes an 11-base-pair promoter segment that has homology with the binding site for the NF-kappa B transactivating factor. Our findings indicate that constitutive expression of the vimentin gene under the control of the Tax protein may be relevant in understanding the progression of the lymphoproliferative process associated with human T-cell leukemia virus type I infection.     

Environmentally-Friendly Pesticidal Activities of Callicarpa and Karomia Essential Oils from Vietnam and Their Microemulsions

There is an ongoing interest to identify alternative pesticidal agents to avoid the chronic problems associated with synthetic pesticides. Essential oils have shown promise as botanical pest control agents. In the present study, the essential oils of four members of the Lamiaceae (Callicarpa candicans, C. erioclona, C. macrophylla, and Karomia fragrans; Vietnamese names: Nàng nàng, Tu châu lông mem, Tu châu lá to and Cà diện, respectively), obtained from wild populations in Vietnam, have been obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry. The essential oils were formulated into microemulsions and the essential oils and their microemulsions were screened for mosquito larvicidal activity against Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and for molluscicidal activity against Pomacea canaliculata. Atractylone and (E)-caryophyllene dominated the volatiles of C. candicans (CCEO) and C. erioclona (CEEO), while the major component in C. macrophylla (CMEO) and K. fragrans (KFEO) was (E)-caryophyllene. The essential oils and microemulsions of both C. candicans and C. erioclona exhibited excellent larvicidal activity against all three mosquito species (Ae. aegypti, Ae. albopictus, and Cx. quinquefasciatus) with LC₅₀ values <10 μg/mL. Additionally, the larvicidal activity of the microemulsions were significantly improved compared with their free essential oils, especially for C. candicans and C. erioclona. All four essential oils and their microemulsions showed excellent molluscicidal activity with LC₅₀ <10 μg/mL. In most cases, the essential oils and microemulsions showed greater pesticidal activity against target organisms than the non-target freshwater fish, Oreochromis niloticus. The in silico studies on physicochemical and ADMET properties of the major components in the studied essential oils were also investigated and most of the compounds possessed a favorable ADMET profile. Computational modeling studies of the studied compounds demonstrated a favorable binding interaction with the mosquito odorant-binding protein target and support atractylone, β-selinene, and caryophyllene oxide as potential inhibitors. Based on the observed pesticidal activities of the essential oils and their microemulsions, the Callicarpa species and K. fragrans should be considered for potential cultivation and further exploration as botanical pesticidal agents.     

Quaternary structure of pyruvate carboxylase from Pseudomonas citronellolis.

Physical-chemical studies of pyruvate carboxylase from Pseudomonas citronellolis demonstrate that the enzyme has an alpha 4 beta 4 structure. The individual polypeptides, alpha (Mr = 65,000) and beta (Mr = 54,000), were separated and isolated by preparative gel electrophoresis. Analysis of the relationship between Coomassie blue staining and protein quantity for each polypeptide indicated that the alpha and beta subunits are present in a 1:1 stoichiometry in the native enzyme. Determinations of the molecular weight of the protein by sedimentation equilibrium (Mr = 454,000), gel filtration analysis (Mr = 510,000), disc gel electrophoresis (Mr = 530,000), and mass measurement from the Scanning Transmission Electron Microscope (Mr = 530,000) are consistent with the proposed alpha 4 beta 4 structure. Disc gel electrophoresis studies revealed that under certain circumstances the enzyme may dissociate to a smaller molecular weight species (Mr = 228,000). This dissociation phenomenon could explain the earlier reported observation of Taylor et al. ((1972) J. Biol. Chem 22, 7388-8390) that the enzyme had a molecular weight of 265,000. Evidence from electron microscopic studies shows that the three-dimensional structure of this enzyme is quite distinct from other species of pyruvate carboxylase. The enzyme does not show the typical rhombic appearance which has been noted for chicken liver, sheep liver, and yeast pyruvate carboxylase.