A comparative banding analysis of chromosomes in three species of lemurs (Primates,Lemuridae)

Banded karyotypes were compared in 3 species of lemurs,Lemur catta (2n=56),L. f. fulvus (2n=60) andL. mongoz (2n=60). The karyotypes of the latter 2 species were indistinguishable from each other in both Q-band and G-band patterns, except thatL. mongoz had an unusually large Y chromosome. The karyotypic differences betweenL. catta and the other 2 species were mainly explained by centric fusions (or fissions) and pericentric inversions. Contrary to the general similarity in Q-band and G-band patterns, the C-band patterns were highly variable among the 3 species. All chromosomes ofL. fulvus had a distinctive C-band in the centromeric region, whileL. mongoz had only a few chromosomes with an apparent C-band.L. catta was remarkable by showing interstitial and terminal C-bands in some elements, in addition to the centromeric band which was observed in about 20 pairs.     

Feeding behavior ofLemur catta andLemur fulvus

The feeding behavior of two sympatric species of lemurs, Lemur cattaand Lemur fulvus,was studied in an enclosure simulating a natural habitat at the Duke University Primate Center. L. fulvusspent less time feeding during the day than L. catta.But the former species ate more fruit and had longer feeding bouts on preferred food items than L. catta.They also had a shorter food passage time than L. cattaand their choice of resting places was more influenced by food distribution. Furthermore, the two lemur species ate parts of different plant species and showed different reactions to chemical plant components. According to these results, L. fulvusis a more conservative feeder than L. catta.These interspecific differences in feeding behavior may be one of a number of differences that allow the two species to coexist. In allopatry, however, L. fulvusmay also adopt feeding patterns similar to those of L. catta.But L. cattawas never found to change its feeding strategies in different areas. It may be this option of L. fulvusto adopt different feeding strategies in different situations that allows this species to have the widest range of all Malagasy lemurs. Duke University Primate Center Publication No. 259.     

The establishment of two parasites of the diamond-back mothPlutella xylostella [Lep.: Plutellidae] in Trinidad,W.I.

The diamond-back moth,Plutella xylostella (L.) is a major pest of cruciferous crops in Trinidad, West Indies. Pesticides are applied as a control measure but it is now resistant to several of them. Indigenous parasitesApanteles aciculatus (Ashm.),Apanteles sp. (glomeratus group),Spilochalcis hirtifemora (Ashm.) andTrichogramma brasiliensis (Ashm.) are unable to exert economic control.Apanteles plutellae (Kurdj.) andTetrastichus sokolowskii Kurdj. were introduced and are now well established. It is recommended to introduce additional parasitesMacromalon sp. andThyraeella collaris (Grav.) in order to obtain complete biological control.     

NaturalMycoplasma arthritidis infection in mice

B6C3F₁ mice from a hybrid production colony frequently were serologically positive by enzyme-linked immunosorbent assay (ELISA) and consistently negative by culture forMycoplasma pulmonis. Subsequently, 162 mice were obtained and intensively studied using an expanded group of cultural procedures, ELISA, and histopathology. Lesions attributable to mycoplasma infection were not found, butMycoplasma arthritidis was isolated from 20 mice. TheM. pulmonis ELISA was positive (IgM, IgG, or both) in 113 mice. Selected sera were tested simultaneously in both theM. pulmonis ELISA and in an ELISA usingM. arthritidis antigen, and were found to be positive in both the IgM and IgG classes in both ELISAs. Thus, cross-reacting antibody was produced in mice naturally infected withM. arthritidis, confirming previous observations based on experimental infections. To our knowledge, this is the first report of naturalM. arthritidis infection in laboratory mice.     

Disease-parasitoid relationships in natural populations ofLymantria dispar [Lep.: Lymantriidae] in the Northeastern United States

ImmatureLymantria dispar L. were collected from 6 geographically distinct populations over 2 years to determine correlations between parasitoid and disease incidences. Incidence of the nuclear polyhedrosis virus disease (NPV) was found to be positively correlated with incidences of the parasitoidsApanteles melanoscelus (Ratzeburg) andParasetigena silvestris (Robineau-Desvoidy).     

A component of the fraction of porcine light chains structurally related to heavy chains

In the previous paper (Rejneket al., 1967) we described the fractionation of light chains (L) by Zn ions resulting in an accumulation of antigenic determinants of the heavy chain (H) in the Zn precipitate. Peptide maps of the obtained fractions of the L chains differ considerably from each other. Peptides of the L chains, the position of which corresponds within the experimental error to peptides of the H chain may be detected by comparing them with the peptide map of the H chains. The number of such peptides increases with qualitatively assayed accumulation of the component precipitated with anti-H serum during fractionation. The concentration of N-terminal glutamic acid, characteristic for the H chains increases at the same time.     

Biological control of the weed,Chromolaena odorata [Asteraceae], byPareuchaetes pseudoinsulata [Lep.: Arctiidae] on Guam and the northern Mariana Islands

Chromolaena odorata L. is a major weed of tropical plantations and pasture lands.Pareuchaetes pseudoinsulata Rego Barros [Lep.: Arctiidae] was mass-reared and released to control the weed on the Mariana Islands of Guam, Rota, Tinian and Saipan in the western Pacific. One year following establishment ofP. pseudoinsulata on Guam, the weed was reduced 100% at 3 of 4 sites monitored with fixed quadrats. Seed production was prevented if defoliation occurred prior to the beginning of the flowering season. If defoliation occurred shortly after flowering began, the developing seeds were eaten byP. pseudoinsulata or there was a significant reduction in weight and germination of seeds that matured. Eighteen months after establishing on Guam,P. pseudoinsulata had defoliated approximately 25,000 hectares of the weed. This is the 1^st report on the quantitative impact of any control agent forC. odorata, and though the long term effect of the insect is still unknown, these results are encouraging.     

Synaptonemal complex analysis of heteromorphic trivalents in Lemur hybrids

Synaptonemal complexes (SCs) in surface spread pachytene spermatocytes of Lemur resemble those in other mammals and are of two types: metacentric (or submetacentric) and acrocentric, with a very short second arm. In autosomal SC and mitotic karyotypes of Lemur fulvus (2n=60) a 11 proportionality in relative length is observed as in other mammals. In an intraspecific lemur hybrid (2n=55) obtained by mating L. fulvus rufus (2n=60) x L. fulvus collaris (2n=51), G-band patterns show that 10 single acrocentric mitotic chromosomes correspond to the arms of 5 single metacentrics, implying homology. It is inferred that the metacentrics have evolved by centric (Robertsonian) fusion of the acrocentrics. In the SC karyotype of the hybrid all SCs are normal except for five which have the configurations expected of metacentric-acrocentric trivalents. Similarly, in L. f. collaris (2n= 51), with one unpaired metacentric and two unpaired acrocentrics, one such SC trivalent is present in the complement. In an SC trivalent, each of the acrocentric long axes is synapsed with an arm of the metacentric axis, confirming the homology predicted from banding similarities. At late zygotene, the acrocentric short arms, which are non-homologous, are the last to pair, demonstrating that synapsis of the homologous arms occurs first. At later pachytene the acrocentric short arms are fully synapsed, producing a short SC side arm. This subsequent non-homologous synapsis is taken to be an instance of the synaptic adjustment phenomenon which has been shown to lead to non-homologous synapsis in a duplication and several inversions in the mouse. The kinetochore of the metacentric is the same size as those of the acrocentrics, and thus is unlikely to have arisen by true centromeric fusion, but rather by a translocation. The kinetochores of the acrocentrics always lie together on the same side of the metacentric kinetochore (cis configuration), implying a single pairing face on the metacentric axis. The observed trivalent configuration may well constitute a prerequisite for proper meiotic disjunction in metacentric-acrocentric heterozygotes. Such a mechanism is consistent with fertility regularly observed in such hybrid lemurs.     

On the carrying behaviour of basic South American primates

InCallithrix, Saguinus, Aotus, andCallicebus other group members than the mother participate in infant care. Differences among these species are obvious in respect to the time of being off any caregiver, and in respect to the carrying position (Aotus andCallicebus). Alloparental care, a basic behaviour pattern in these species, has evolved from the parking behaviour of the prosimians. The infants are «parked» at other group members.     

MiR-199a is overexpressed in plasma of type 2 diabetes patients which contributes to type 2 diabetes by targeting GLUT4

Decreased GLUT4 expression and impaired GLUT4 cell membrane translocation are involved in type 2 diabetes mellitus (T2DM) pathogenesis so the factors impacting GLUT4 expression may be associated with T2DM. In this study, we identified four miRNAs: miR-31, miR-93, miR-146a, and miR-199a which suppress GLUT4 expression in HEK293T cells. Subsequently, we determined expression of these four miRNAs in plasma samples of T2DM patients, T2DM susceptible individuals, and healthy controls and found miR-199a was overexpressed in patients’ plasma compared with healthy control. Because the miR-199a binding site in GLUT4 3′UTR is highly conserved among vertebrates, we detected the glucose uptake in rat L6 myoblast cells through gain- and loss-of-function of miR-199a. We found that miR-199a can repress glucose uptake in L6 cells, which was rescued by GLUT4 overexpression. These results indicate that T2DM patients may have a high level miR-199a that reduce GLUT4 expression and contribute to the insulin resistance. Hence, miR-199a may be a novel biomarker for risk estimation and classification in T2DM patients.     

Biological control ofDiatraea saccharalis (F.) in Barbados byApanteles flavipes Cam. andLixophaga Diatraeae T. T.

Early biological control attempts ofDiatraea saccharalis in Barbados had failed. Subsequent intensive release campaigns of several parasite species from the Neotropics. Africa and India resulted in the temporary establishment ofMetagonistylum minense andTrichogramma japonicum and the permanent establishment ofLixophaga diatraeae andApanteles flavipes. The latter built up an extraordinarily high population level within a short period of time. From damage assessments it is evident that due to high parasitism crop damage was reduced considerably. The joint borer infestation which fluctuated around 15% until 1966 decreased to less than 6% in 1970.

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Résumé Des essais de lutte biologique contreDiatraea saccharalis ont été poursuivis à la Barbade pendant plus de 40 ans. Des libérations en masse deTrichogramma japonicum, faites jusqu’en 1958, se révélèrent infructueuses; la mouche de Cuba,Lixophaga diatraeae, fut introduite au début de l’année 1960, mais sa répartition demeura inégale et sa fréquence généralement faible jusqu’en 1968, date à laquelle elle se répandit soudain dans toute l’?le et augmenta en abondance (moyenne de parasitisme en 1968: 13,6%). Tout s’est passé comme si, durant les années précédentes, une race s’était développée qui est maintenant mieux adaptée aux conditions environnantes de la Barbade. En 1966 et 1967, plusieurs autres espèces de parasites furent introduites à la Barbade. Parmi elles,Metagonistylum minense etTrichogramma fasciatum s’établirent temporairement, tandis queApanteles flavipes, introduite des Indes, s’acclimata d’elle-même en permanence. A la suite d’une libération d’environ 2 000 individus en juillet et ao?t 1966, ce parasite fut retrouvé pour la première fois, plus d’un an après, en octobre 1967; à la fin de 1969, il avait colonisé toute l’?le avec un taux de parasitisme de 0,5 à 95,5% et en moyenne de 30,3%. Ces deux dernières années, la réduction des dégats a produit une augmentation de revenu estimée à 315 000 et 405 000 ￡, respectivement.

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Presented at the symposium OILB on borers of graminaceous plants. Paris, 24th sept. 1970.