The phylogeny of the ant tribe Formicini (Hymenoptera: Formicidae) with the description of a new genus

Abstract. The holarctic ant tribe Formicini is revised, the new genus Bajcaridris described, and possible phylogenetic relationships are discussed. The subgenus Iberoformica is synonymized with Formica. A synopsis, diagnosis and keys to the genera are provided.     

世居及移居高原青少年最大有氧能力的特征

本文报道海拔３４１７ｍ和４２８０ｍ地区世居藏族和移居汉族青少年运动状态下心肺功能的对比研究。结果显示：３４１７ｍ和４２８０ｍ世居藏族的最大氧耗量、无氧阈值及最大心输出量都明显大于汉族,血氧饱和度（Ｓａｏ２）随运动负荷的增加而降低。海拔３４１７ｍ藏、汉族的△Ｓａｏ２分别为７．４６％和１０．０３％,４２８０ｍ处为８．５７％和１３．７５％,最大心率随海拔升高而下降。研究提示,藏族青少年有较高的最大有氧能力,反映了他们对低氧环境的适应优势。     

Sex differences in the rate of fatigue development and recovery

Background

Many musculoskeltal injuries in the workplace have been attributed to the repetitive loading of muscle and soft tissues. It is not disputed that muscular fatigue is a risk factor for musculoskeltal injury, however the disparity between gender with respect to muscular fatigability and rate of recovery is not well understood. Current health and safety guidelines do not account for sex differences in fatiguability and may be predisposing one gender to greater risk. The purpose of this study was to quantify the sex differences in fatigue development and recovery rate of lower and upper body musculature after repeated bouts of sustained isometric contractions.

Methods

Twenty-seven healthy males (n = 12) and females (n = 15) underwent bilateral localized fatigue of either the knee extensors (male: n = 8; female: n = 8), elbow flexors (male: n = 8; female: n = 10), or both muscle groups. The fatigue protocol consisted of ten 30-second sub-maximal isometric contractions. The changes in maximum voluntary contraction (MVC), electrically evoked twitches, and motor unit activation (MUA) were assessed along with the ability to control the sustained contractions (SLP) during the fatigue protocol using a mixed four-factor repeated measures ANOVA (gender × side × muscle × time) design with significance set at p < 0.05.

Results

There was a significant loss of MVC, MUA, and evoked twitch amplitude from pre- to post-fatigue in both the arms and legs. Males had greater relative loss of isometric force, a higher rate of fatigue development, and were less capable of maintaining the fatiguing contractions in the legs when compared to the females.

Conclusion

The nature of the induced fatigue was a combination of central and peripheral fatigue that did not fully recover over a 45-minute period. The results appear to reflect sex differences that are peripheral, and partially support the muscle mass hypothesis for explaining differences in muscular fatigue.

     

Gap junctional intercellular communication of bovine luteal cells from several stages of the estrous cycle: Effects of prostaglandin F2α, protein kinase C and calcium

Cellular interactions mediated by both contact-dependent and contact-independent mechanisms are probably important to maintain luteal function. The present studies were performed to evaluate the effects of luteotropic and luteolytic hormones, and also intracellular regulators, on contact-dependent gap junctional intercellular communication (GJIC) of bovine luteal cells from several stages of luteal development. Bovine corpora lutea (CL) from the early, mid and late luteal phases of the estrous cycle were dispersed with collagenase and incubated with no treatment, LH, PGF or LH + PGF (Experiment 1), or with no treatment, or agonists or antagonists of protein kinase C (TPA or H-7) or calcium (A23187 or EGTA; Experiment 2). After incubation, media were collected for determination of progesterone concentrations. Then the rate of GJIC was evaluated for small luteal cells in contact with small luteal cells, and large luteal cells in contact with small luteal cells by using the fluorescence recovery after photobleaching technique and laser cytometry. Luteal cells from each stage of the estrous cycle exhibited GJIC, but the rate of GJIC was least (P<0.05) for luteal cells from the late luteal phase. LH increased (P<0.05) GJIC between small luteal cells from the mid and late but not the early luteal phase. PGF increased (P<0.05) GjIC between small luteal cells from the mid luteal phase and diminished (P<0.05) LH-stimulatory effects on GjIC between small luteal cells from the late luteal phase. Throughout the estrous cycle, TPA decreased (P<0.05) the rate of GjIC between large and small, and between small luteal cells, and A23187 decreased (P<0.05) the rate of GJIC between large and small luteal cells. LH and LH + PGF, but not PGF alone increased (P<0.05) progesterone secretion by luteal cells from the mid and late luteal phases. Agonists or antagonists of PKC or calcium did not affect progesterone secretion by luteal cells. These data demonstrate that both luteal cell types communicate with small luteal cells, and the rate of communication depends on the stage of luteal development. LH and PGF affect GjIC between small luteal cells during the fully differentiated (mid-luteal) and regressing (late luteal) stages of the estrous cycle. In contrast, at all stages of luteal development, activation of PKC decreases GjIC between small and between large and small luteal cells, whereas calcium ionophore decreases GjIC only between large and small luteal cells. Luteotropic and luteolytic hormones, and intracellular regulators, may be involved in regulation of cellular interactions within bovine CL which likely is an important mechanism for coordination of luteal function.     

Ovarian follicular development and oocyte quality in anestrous ewes treated with melatonin, a controlled internal drug release (CIDR) device and follicle stimulating hormone

The objective of the current study was to determine the effects of hormonal treatments on ovarian follicular development and oocyte quality in anestrous ewes. Multiparous crossbred (RambouilletxTarghee) ewes were given melatonin implants (MEL) and/or controlled internal drug release (CIDR) devices in conjunction with follicle stimulating hormone (FSH) during anestrus (March-May). In Experiment 1, ewes (n=25) were assigned randomly to four groups (n=4-7/group) in a 2x2 factorial arrangement [+/-MEL and +/-CIDR], resulting in Control (no treatment), CIDR, MEL, and MEL/CIDR groups, respectively. Ewes received an implant containing 18 mg of melatonin (Melovine) on Day 42 and/or a CIDR from Days 7 to 2 (Day 0: oocyte collection). In Experiment 2, ewes (n=12) were assigned randomly to two groups (n=6/group; 1CIDR or 2CIDR) and received the same type of melatonin implant on Day 60. All ewes received a CIDR device from Days -22 to -17 and 2CIDR ewes received an additional CIDR device from Days -10 to -2. In both experiments, ewes were given FSH im twice daily (morning and evening) on Days -2 and -1 (Day -2: 5 units/injection; Day -1: 4 units/injection). On the morning of Day 0, ovaries were removed, follicles>or=1 mm were counted, and oocytes were collected. Thereafter oocytes were matured and fertilized in vitro. In Experiment 1, the number of visible follicles and the rates of oocyte recovery and in vitro maturation were similar (P>0.10) for Control, CIDR, MEL and MEL/CIDR (overall 29.7+/-2.9%, 89.9+/-7.1% and 95.0+/-2.0%, respectively). The rates of in vitro fertilization (IVF) were lower (P<0.01) for CIDR and MEL/CIDR than for Control and MEL groups (10.3% and 10.1% versus 20.0% and 18.5%, respectively). In Experiment 2, the number of visible follicles, and the rates of oocyte recovery and in vitro maturation were similar (P>0.10) for 1CIDR and 2CIDR groups (overall 27.3+/-3.2%, 92.1+/-2.7% and 90.2+/-1.9%, respectively). However, the rates of IVF were lower (P<0.01) for 2CIDR than 1CIDR group (30.2% versus 58.0%, respectively). In summary, when treatment with P4 commenced only 2 d before oocyte collection, rates of IVF were reduced in both experiments. Therefore, progestin treatment protocols used in ovine IVF programs should be carefully designed to minimize adverse effects on fertilization rates. In addition, melatonin treatment did not affect follicular development and oocyte quality for anestrous ewes.     

Changes in cell proliferation,but not in vascularisation are characteristic for human endometrium in different reproductive failures - a pilot study

Background  

Reproductive failure, determined as recurrent spontaneous abortions (RSA) or recurrent implantation failure (RIF) in women is not well understood. Several factors, including embryo quality, and cellular and molecular changes in endometrium may contribute to the insufficient feto-maternal interaction resulting in reproductive failure. Prior clinical studies suggest an inadequate endometrial growth and development of the endometrium, leading to a lesser endometrial thickness.     

Differences in growth and water relations among Phaseolus vulgaris cultivars in response to induced drought stress

Relatively little ecophysiological research has been conducted to determine the responses to drought of Phaseolus vulgaris. Four bean cultivars (cvs.) from Brazil, A320, Carioca, Ouro Negro and Xodó were submitted to an imposed water deficit in order to evaluate the importance of some adaptive mechanisms of drought resistance through the analysis of growth parameters, water status, gas exchange and indicators of tolerance mechanisms at the cellular level. During the drought treatment, relative growth rates were more reduced for A320 and Xodó than Carioca and Ouro Negro. A320 closed its stomata very rapidly and complete stomatal closure was obtained at Psi(w)=-0.6 MPa, in contrast to the other cvs. where stomata were fully closed only at Psi(w)=-0.9 MPa. Net assimilation rates were closely related to stomatal conductances. Mechanisms at the cellular level appeared to be mostly important for higher tolerance. Carioca and Ouro Negro, when compared to A320 and Xodó, were characterized by having better drought tolerance mechanisms and higher tissue water retention capacity leading to a better growth under water deficits. The leaf dehydration rates of those cvs. were slow whereas those of the drought sensitive cvs. were rapid. The results were confirmed by the electrolyte leakage test and leaf osmotic potential measurements, which indicated higher membrane resistance and osmotic adjustment in the two tolerant cvs. Carioca and Ouro Negro. It appears from this study that despite being cultivated in the same geographical region, the four cvs. of P. vulgaris displayed somewhat different drought adaptive capacities for prolonged drought during the vegetative phase.     

Relationships in the Drosophila obscura species group, inferred from mitochondrial cytochrome oxidase II sequences

We compare the sequences for the mitochondrial cytochrome oxidase II gene of 13 species of the Drosophila obscura group. The survey includes six members of the D. affinis subgroup, four of the D. pseudoobscura subgroup, and three of the D. obscura subgroup. In all species, the gene is 688 nucleotides in length, encoding a protein of 229 amino acids plus the first position T of the stop codon. The sequences show the typical high-transition bias for closely related species, but that bias is essentially eliminated for species pairs of > 5% sequence divergence. The phylogenetic relationships in the species group are inferred using both neighbor-joining and maximum parsimony. The two procedures give comparable results, showing that the D. affinis and D. pseudoobscura subgroups are monophyletic groupings that appear to have closer affinities to one another than either has to the D. obscura subgroup. We use transversion distances to estimate times of divergence, on the basis of three different estimates of the time of separation of the D. obscura species group from the D. melanogaster group. If that event occurred 35 Mya, then we can estimate the origin of the nearctic forms at approximately 22 Mya and the separation of the D. affinis and D. pseudoobscura subgroups at approximately 17 Mya.