Preference of dairy cows for ryegrass, white clover and red clover, and its effects on nutrient supply and milk quality

Two experiments were conducted with 30 dairy cows each, to study the preference for fresh (Experiment 1) and ensiled (Experiment 2) ryegrass, white and red clover. Both experiments consisted of three choice diets with white or red clover or both, offered with ryegrass, and two diets with ryegrass mixed with white or red clover (40% clover). Cows consumed diets with 37.7% fresh white and 45.9% red clover, and no preference was observed when the cows were offered all three forages. By contrast, cows preferred white and red clover silage (73.0 and 69.2%, respectively) over ryegrass silage (of lower nutritive quality). When offered three forages, cows preferred white (59.8%) over red clover (17.5%) and ryegrass (22.7%). Choice diets resulted in diets similar (fresh forages) or higher in nutrient content and digestibility (silages). Treatments did not affect feed intake and performance. Choices compared to mixed diets with red clover silage were preferable regarding the fatty acid composition of the milk fat. Obviously, only large differences in nutrient and energy concentration facilitate preferences for clovers over ryegrass, which could, depending on clover type, be beneficial in terms of the milk's fatty acid composition.

Age and gender-dependent alternative splicing of P/Q-type calcium channel EF-hand

Ca(v)2.1 Ca(2+) channels (P/Q-type), which participate in various key roles in the CNS by mediating calcium influx, are extensively spliced. One of its alternatively-spliced exons is 37, which forms part of the EF hand. The expression of exon 37a (EFa form), but not exon 37b (EFb form), confers the channel an activity-dependent enhancement of channel opening known as Ca(2+)-dependent facilitation (CDF). In this study, we analyzed the trend of EF hand splice variant distributions in mouse, rat and human brain tissues. We observed a developmental switch in rodents, as well as an age and gender bias in human brain tissues, suggestive of a possible role of these EF hand splice variants in neurophysiological specialization. A parallel study performed on rodent brains showed that the data drawn from human and rodent tissues may not necessarily correlate in the process of aging.

Molecular characterization of HOXA13 polyalanine expansion proteins in hand-foot-genital syndrome

We report on a father and daughter with hand-foot-genital syndrome (HFGS) with typical skeletal and genitourinary anomalies due to a 14-residue polyalanine expansion in HOXA13. This is the largest (32 residues) polyalanine tract so far described for any polyalanine mutant protein. Polyalanine expansion results in protein misfolding, cytoplasmic aggregation and degradation; however, HOXA13 polyalanine expansions appear to act as loss of function mutations in contrast to gain of function for HOXD13 polyalanine expansions. To address this paradox we examined the cellular consequences of polyalanine expansions on HOXA13 protein using COS cell transfection and immunocytochemistry. HOXA13 polyalanine expansion proteins form cytoplasmic aggregates, and distribution between cytoplasmic aggregates or the nucleus is polyalanine tract size-dependent. Geldanamycin, an Hsp90 inhibitor, reduces the steady-state abundance of all polyalanine-expanded proteins in transfected cells. We also found that wild-type HOXA13 or HOXD13 proteins are sequestered in HOXA13 polyalanine expansion cytoplasmic aggregates. Thus, the difference between HOXA13 polyalanine expansion loss-of-function and HOXD13 polyalanine expansion dominant-negative effect is not the ability to aggregate wild-type group 13 paralogs but perhaps to variation in activities associated with refolding, aggregation or degradation of the proteins.

Preference polymorphism for coloration but no speciation in a population of Lake Victoria cichlids

Female mating preference based on male nuptial coloration has been suggested to be an important source of diversifying selection in the radiation of Lake Victoria cichlid fish. Initial variation in female preference is a prerequisite for diversifying selection; however, it is rarely studied in natural populations. In clear water areas of Lake Victoria, the sibling species Pundamilia pundamilia with blue males and Pundamilia nyererei with red males coexist, intermediate phenotypes are rare, and most females have species-assortative mating preferences. Here, we study a population of Pundamilia that inhabits turbid water where male coloration is variable from reddish to blue with most males intermediate. We investigated male phenotype distribution and female mating preferences. Male phenotype was unimodally distributed with a mode on intermediate color in 1 year and more blue-shifted in 2 other years. In mate choice experiments with females of the turbid water population and males from a clearer water population, we found females with a significant and consistent preference for P. pundamilia (blue) males, females with such preferences for P. nyererei (red) males, and many females without a preference. Hence, female mating preferences in this population could cause disruptive selection on male coloration that is probably constrained by the low signal transduction of the turbid water environment. We suggest that if environmental signal transduction was improved and the preference/color polymorphism was stabilized by negative frequency-dependent selection, divergent sexual selection might separate the 2 morphs into reproductively isolated species resembling the clear water species P. pundamilia and P. nyererei.

Left parietal activation related to planning, executing and suppressing praxis hand movements

OBJECTIVE: We sought to investigate the activity of bilateral parietal and premotor areas during a Go/No Go paradigm involving praxis movements of the dominant hand. METHODS: A sentence was presented which instructed subjects on what movement to make (S1; for example, "Show me how to use a hammer."). After an 8-s delay, "Go" or "No Go" (S2) was presented. If Go, they were instructed to make the movement described in the S1 instruction sentence as quickly as possible, and continuously until the "Rest" cue was presented 3 s later. If No Go, subjects were to simply relax until the next instruction sentence. Event-related potentials (ERP) and event-related desynchronization (ERD) in the beta band (18-22 Hz) were evaluated for three time bins: after S1, after S2, and from -2.5 to -1.5 s before the S2 period. RESULTS: Bilateral premotor ERP was greater than bilateral parietal ERP after the S2 Go compared with the No Go. Additionally, left premotor ERP was greater than that from the right premotor area. There was predominant left parietal ERD immediately after S1 for both Go and No Go, which was sustained for the duration of the interval between S1 and S2. For both S2 stimuli, predominant left parietal ERD was again seen when compared to that from the left premotor or right parietal area. However, the left parietal ERD was greater for Go than No Go. CONCLUSION: The results suggest a dominant role in the left parietal cortex for planning, executing, and suppressing praxis movements. The ERP and ERD show different patterns of activation and may reflect distinct neural movement-related activities. SIGNIFICANCE: The data can guide further studies to determine the neurophysiological changes occurring in apraxia patients and help explain the unique error profiles seen in patients with left parietal damage.

Mapping Individual Variation in Male Mating Preference Space: Multiple Choice in a Color Polymorphic Cichlid Fish

Sexual selection theory largely rests on the assumption that populations contain individual variation in mating preferences and that individuals are consistent in their preferences. However, there are few empirical studies of within-population variation and even fewer have examined individual male mating preferences. Here, we studied a color polymorphic population of the Lake Victoria cichlid fish Neochromis omnicaeruleus, a species in which color morphs are associated with different sex-determining factors. Wild-caught males were tested in three-way choice trials with multiple combinations of different females belonging to the three color morphs. Compositional log-ratio techniques were applied to analyze individual male mating preferences. Large individual variation in consistency, strength, and direction of male mating preferences for female color morphs was found and hierarchical clustering of the compositional data revealed the presence of four distinct preference groups corresponding to the three color morphs in addition to a no-preference class. Consistency of individual male mating preferences was higher in males with strongest preferences. We discuss the implications of these findings for our understanding of the mechanisms underlying polymorphism in mating preferences.

Hotshots, hot spots, and female preference: exploring lek formation models with a bower-building cichlid fish

In many animals, males congregate in leks that females visit for the sole purpose of mating. We observed male and female behavior on 3 different-sized leks of the bower-building cichlid fish Nyassachromis cf. microcephalus to test predictions of 3 prominent lek models: the "hotshot," "hot spot," and "female preference" models. In this system, we were able to refine these predictions by distinguishing between indirect mate choice, by which females restrict their set of potential mates in the absence of individual male assessment, and direct mate choice, by which females assess males and their territories through dyadic behavioral interactions. On no lek were males holding central territories favored by indirect or direct mate choice, contrary to the prediction of the hotshot model that leks form because inferior males establish territories surrounding hotshot males preferred by females. Average female encounter rate of males increased with lek size, a pattern typically interpreted as evidence that leks form through female preference for lekking males, rather than because males congregate in hot spots of high female density. Female propensity to engage in premating behavior once courted did not increase with lek size, suggesting female preference for males on larger leks operated through indirect choice rather than direct choice based on individual assessment. The frequency of male-male competitive interactions increased with lek size, whereas their foraging rate decreased, implying a cost to males maintaining territories on larger leks. Together these data most strongly support the female preference model, where females may benefit through indirect mate choice for males able to meet the competitive cost of occupying larger leks.

Language attitudes and language shift among ethnic migrants in Khartoum

This paper investigates language attitudes among ethnic migrant groups in Khartoum, the capital city of Sudan. A questionnaire was used to collect data on language preference, language parents prefer their children to learn, and reasons for language preference. Results suggest that while positive attitude played a significant role in learning Arabic among some of the groups under investigation, it proved to be of no help in maintaining the groups’ ethnic languages. Arabic was reported as very important for education, religious activities, economic privileges and social interaction. Ethnic languages, on the other hand, were preferred for purely symbolic reasons (symbolizing groups’ ethnic identity).